Datasets:

sitloboi2012

/

semiconductor_scirepeval_v1

like 0

[ { "abstract": "Abstract Colloidal semiconductor nanocrystals (SCNCs) or, more broadly, colloidal quantum nanostructures constitute outstanding model systems for investigating size and dimensionality effects. Their nanoscale dimensions lead to quantum confinement effects that enable tuning of their optical and electronic properties. Thus, emission color control with narrow photoluminescence spectra, wide absorbance spectra, and outstanding photostability, combined with their chemical processability through control of their surface chemistry leads to the emergence of SCNCs as outstanding materials for present and next generation displays. In this Review, we present the fundamental chemical and physical properties of SCNCs, followed by a description of the advantages of different colloidal quantum nanostructures for display applications. The open challenges with respect to their optical activity are addressed. Both photoluminescent and electroluminescent display scenarios utilizing SCNCs are described.", "author_names": [ "Yossef E Panfil", "Meirav Oded", "Uri Banin" ], "corpus_id": 4754818, "doc_id": "4754818", "n_citations": 85, "n_key_citations": 0, "score": 1, "title": "Colloidal Quantum Nanostructures: Emerging Materials for Display Applications", "venue": "Angewandte Chemie", "year": 2018 }, { "abstract": "Professor Uri Banin holds the Alfred Erica Larisch Memorial Chair at the Institute of Chemistry and the Center for Nanoscience and Nanotechnology at the Hebrew University of Jerusalem (HU) Banin obtained his PhD in Physical Chemistry (Magna Cum Laude, 1995) from the Hebrew University of Jerusalem and performed his postdoctoral research at the University of California at Berkeley (1994 97) He was the founding director of the HU Center for Nanoscience and Nanotechnology (2001 2010) and is a founder of Qlight Nanotech that developed colloidal quantum materials for display applications, and was acquired by Merck KGaA, Darmstadt, Germany. His research focuses on the chemistry and physics of nanocrystals including synthesis of nanoparticles, sizeand shape dependent properties, and emerging applications in displays, lighting, solar energy harvesting, 3D printing, electronics, and biology. Meirav Oded", "author_names": [ "Yossef E Panfil", "Meirav Oded", "Nir Waiskopf", "Uri Banin" ], "corpus_id": 229371282, "doc_id": "229371282", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Material Challenges for Colloidal Quantum Nanostructures in Next Generation Displays", "venue": "", "year": 2020 }, { "abstract": "Colloidal quantum materials are nanocrystals containing hundreds to thousands of atoms that exhibit unique properties resulting from their small finite dimensions. The extraordinary flexibility in tuning their properties via composition, size and dimensionality related quantum confinement effects and surface engineering combined with their scalable bottom up manufacturing has already led to their commercialization in different light emitting applications, such as materials for displays and as fluorescent agents for imaging and sensing. Beyond light emission, harnessing absorbed light energy to perform useful chemical work is an important new avenue for diverse applications of the colloidal quantum materials. Here, we introduce the colloidal quantum materials and their virtues, focusing on the \"all in one system\" concept for semiconductor metal hybrid nanoparticles acting as photocatalysts. Next, their emerging photocatalytic functionalities are highlighted, including their action as photocatalysts for solar to fuel conversion and as photoinitiators for photo curing and biomedical applications, such as phototherapy, sterilization, and diagnostics.", "author_names": [ "Nir Waiskopf", "Uri Banin" ], "corpus_id": 202208987, "doc_id": "202208987", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Colloidal Quantum Materials for Photocatalytic Applications", "venue": "", "year": 2019 }, { "abstract": "Abstract Metal halide perovskites have affirmed their pedigree as extraordinary semiconducting materials, exhibiting properties rivalling those observed in single crystal compound semiconductors. Perovskites show tremendous versatilities in both structure and composition tuning, and therefore applications ranging from optoelectronics to X ray imaging and spintronics, neuromorphic electronics are emerging. Moreover, when their dimensions become comparable to the exciton Bohr radius, perovskite nanostructures and layered systems display remarkable properties because of quantum confinement. Nanostructured and lower dimensional layered perovskites exhibit properties that are yet to be fully exploited such as extraordinarily high luminescence, narrow emissions, high exciton binding energies, strong non linear phenomena, and carrier cascade characteristics. This review, while highlighting the frontier phenomena that continue to be unravelled, outlines how confined structures of these materials have demonstrated properties that promise to unlock exceptional quantum phenomena to challenge the optoelectronic limits.", "author_names": [ "Sneha Avinash Kulkarni", "Natalia Yantara", "Kim Seng Tan", "Nripan Mathews", "Subodh Gautam Mhaisalkar" ], "corpus_id": 214300586, "doc_id": "214300586", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Perovskite nanostructures: Leveraging quantum effects to challenge optoelectronic limits", "venue": "", "year": 2020 }, { "abstract": "Semiconductor quantum nanostructures, such as 0D quantum dots (QDs) 1D nanorods and 2D nanoplatelets (NPLs) quantum rings (QRs) and quantum wells (QWs) exhibit unique quantum mechanical and optoelectronic properties due to spatial confinement of excitons in one or more dimensions ~10 9 m) They have received increasing research interest in recent years owing to their intriguing fundamental properties that can be leveraged for potential applications in optoelectronic and display devices as cost effective and quantum efficient luminophores. They have been successfully used to implement and design light emitting diodes (LEDs) lasers, photodetectors, solar cells, biomedical imagers, etc. This is owing to their morphological bandgap tunability, fast fluorescence lifetime and unique optical characteristics supporting tunable pure color or wide spectral emission. Among the wide range of available and newly studied semiconductor quantum nanostructures, firstly (i) NPLs and QRs of II VI materials and alloys thereof, and secondly (ii) QDs and QWs of III V dilute nitride/bismide alloy materials are two families of nanostructures that have emerged as very promising candidates for novel semiconductor device and optoelectronic applications. In this thesis, we report studies on the aforementioned two families of semiconductor quantum nanostructures. The first part of the thesis focuses on the study of II VI (CdSe and CdS) NPLs and optoelectronic properties thereof under varying physical conditions such as geometrical dimensions, temperature, material composition, topology and optical polarization. NPLs are a unique class of atomically flat quasi 2D quantum confined nanocrystals, often synthesized using wide bandgap II VI materials, having well defined thicknesses of several monolayers (MLs) Their sizes enable them to be colloidally suspended in solution. Recent advancements in colloidal chemistry has led to the efficient synthesis of high quality single crystal NPL samples having reduced nonradiative recombination paths and enhanced optical properties. They exhibit strong 1D confinement as their thickness is very", "author_names": [ "Sumanta Bose" ], "corpus_id": 139176055, "doc_id": "139176055", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Semiconductor quantum nanostructures for optoelectronic applications", "venue": "", "year": 2018 }, { "abstract": "In recent years, lead halide perovskites have not only proven to be a promising material for solar cell applications, but they have also shown a huge potential for light emitting devices and other optoelectronic applications. Most of the initial studies focused on bulk perovskite materials. However, emerging colloidal perovskite nanocrystals have been shown to exhibit superior qualities relating to their efficiency and functionality. On the nanoscale, size dependent effects can be exploited to tune the nanocrystals' properties. In the present work, two dimensional perovskite nanoplatelets and quasi two dimensional layered hybrid perovskites are investigated. A new and systematic variation of the ligand concentration during the nanocrystal synthesis is presented. This enables the fabrication of colloidal two dimensional methylammonium lead bromide perovskite nanoplatelets of varying thicknesses down to only a single unit cell. Photoluminescence and absorption spectra show the appearance of clear excitonic features in the thinnest structures and a blue shift in the emission wavelength of more than 90 nm in comparison to the bulk counterpart. Additionally, in the thinnest structures the exciton binding energy increases up to several hundreds of meV due to a reduced excitonic screening. For the first time the quantum size effect in these nanoplatelets is quantitatively described through model calculations. Miniband formation in the multilayer structures lowers the emission energy with respect to the isolated nanoplatelet. Thickness dependent photoluminescence lifetime measurements are performed. The recorded lifetimes decrease with thinner nanoplatelets as the exciton binding energy increases. Temperature dependent photoluminescence measurements on cesium lead bromide perovskite nanoplatelets are carried out. A theoretical model considering acoustic and optical phonons as the main sources for scattering of excitons, shows that the former dominate at temperatures below 90 K and the latter above this temperature. Interestingly, temperature dependent time resolved photoluminescence measurements display contributions of bright and dark excitons to the decay curves below 60 K. At higher temperatures an antiquenching behavior of the luminescence is observed, indicating that ligands play an important role in these structures with a high surface to volume ratio. The interlayer distance in layered hybrid perovskites is systematically varied to investigate its impact on structure function relationships and electronic coupling between the perovskite layers. It is found that the optical bandgap is determined mainly by two parameters. First, the length of the organic ligands separating the inorganic perovskite sheets influences the tilt angle of the perovskite octahedra. An increase of the optical bandgap with larger tilt angles is observed. Secondly, electronic coupling between the perovskite sheets constituting the multilayer structures is found to have an impact on the bandgap, albeit significantly smaller than the effect induced by the change in tilt angles. Importantly, the electronic coupling only occurs for perovskite multilayers with an interlayer distance below 1.5 nm. This thesis contributes to a fundamental understanding of optical properties of two dimensional perovskites. It focuses on thickness dependent quantum size effects, exciton phonon interactions, and structure function relationships.", "author_names": [ "Jasmina A Sichert" ], "corpus_id": 200088729, "doc_id": "200088729", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Quantum size effects and carrier dynamics in two dimensional lead halide perovskite nanostructures", "venue": "", "year": 2019 }, { "abstract": "Metal lead halide perovskite nanocrystals have emerged as promising candidates for optoelectronic applications. However, the inclusion of toxic lead is a major concern for the commercial viability of these materials. Herein, we introduce a new family of non toxic reduced dimension Rb2CuX3 (X Br, Cl) colloidal nanocrystals with one dimensional crystal structure consisting [CuX4]3 ribbons isolated by Rb+ cations. These nanocrystals were synthesised using a room temperature method under ambient conditions, which makes them cost effective and scalable. Phase purity quantification was confirmed by Rietveld refinement of powder X ray diffraction and corroborated by 87Rb MAS NMR technique. Both samples also exhibited high thermal stability up to 500 degC, which is essential for optoelectronic applications. Rb2CuBr3 and Rb2CuCl3 display PL emission peaks at 387 nm and 400 nm with high PLQYs of ~100% and ~49% respectively. Lastly, the first colloidal synthesis of quantum confined rubidium copper halide based nanocrystals opens up a new avenue to exploit their optical properties in lighting technology as well as water sterilisation and air purification.", "author_names": [ "Parth Vashishtha", "Thomas J N Hooper", "Yanan Fang", "Deviana Kathleen", "David Giovanni", "Maciej Klein", "Tze Chien Sum", "Subodh Gautam Mhaisalkar", "Nripan Mathews", "Tim White" ], "corpus_id": 229341369, "doc_id": "229341369", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Room temperature synthesis of low dimensional rubidium copper halide colloidal nanocrystals with near unity photoluminescence quantum yield.", "venue": "Nanoscale", "year": 2020 }, { "abstract": "Tunable, narrow linewidth photoluminescence with nearly ideal quantum yields and solution processability make colloidal quantum dots (QDs) a unique class of emitters for a variety of applications including light emitting diodes (LEDs) Wide color gamut and high color saturation that can be achieved with QDs along with recent advances in QD LEDs motivate their use as large area, patternable electroluminescent materials especially in displays. In this review, critical issues in performance and long term stability of QD LEDs, Cd free compositions necessary for practical applications, lower symmetry heterostructures that impart new capabilities, and unconventional fabrication approaches are discussed. As the current CdSe based QD LEDs approach their performance limits, emerging nanorod heterostructures, as exemplified by the double heterojunction nanorods (DHNRs) can extend efficiencies beyond these limits. Furthermore, enhancements in device lifetime and light detection/photovoltaic capabilities using the same high performance DHNR LEDs can allow exciting prospects for novel emissive displays. Such multifunctional LEDs that can be solution processed into large area, mulitcolor pixel arrays may fundamentally alter how we perceive, interact with and utilize display devices.", "author_names": [ "Yiran Jiang", "Seong-Yong Cho", "Moonsub Shim" ], "corpus_id": 139802747, "doc_id": "139802747", "n_citations": 48, "n_key_citations": 0, "score": 0, "title": "Light emitting diodes of colloidal quantum dots and nanorod heterostructures for future emissive displays", "venue": "", "year": 2018 }, { "abstract": "Investigation of carrier transport and electronic properties of highly crosslinked ligand exchanged colloidal quantum dot (QD) assemblies (Fig. 1a b) is vital for the utilization of these class of materials in diverse emerging practical applications. So far, their tunability of energy bandgap and the discrete energy levels formation have attracted great interest in their applications in many devices where optical properties are primarily important (e.g. photovoltaics, displays [QLEDs] and even laser) On the other hand, QD assemblies are prospective for thermoelectric applications, since low dimensionality leads to enhanced Seebeck effect and suppressed thermal conductivity. 3 4 For those applications, some certain doping levels are required; thus knowledge on how many electrons can sit for each QD discrete energy levels is vital. To understand electronic state degeneracy in QD system is challenging since it will be strongly influenced by the energetic landscape of the quantum confinement, in addition to the compound type. So far, it is still too difficult to elucidate degeneracy information only from the optical characterization of the QD assemblies. Here we demonstrate the probing of the electronic state degeneracy of QD assemblies via measurement of electronic transport. High carrier density accumulation in electric double layer transistor (EDLT) of PbS QD, which was gated using ionic liquid, enables us to attain sheet carrier density in the order of 10 cm. In addition to be able to fill almost all of the charge carrier traps in the quantum dot film and make it highly conducting, the high carrier density accumulation is virtually sufficient to greatly control the Fermi level beyond quantum dots` HOMO LUMO, thus accessing the discrete energy levels to fill them. The observation of negative transconductance and conductivity peaks of the EDLT at some certain carrier density value is attributed to the half filling of the discrete energy band of the QDs. From the correlation of the carrier density and QD density in the assembly, the number of accumulated electrons per individual QD can be counted to obtain the numbers of electronic state degeneracy for each discrete energy levels. For PbS QD, as (Fig. 1d) the number of the degeneracy can be approached by both the number of the degeneracy of its bulk material at the conduction minima and the quasi hydrogen model that is used to describe the energetic landscape of a QD. Through this probing, we can know how much dopant is necessary to dope the QDs up to some certain levels required for many applications and to formulate various doping strategies. Refs: [1] M. Kovalenko, ACS Nano 9, 1012 (2015) [2] A. Nurmikko,Nature Nano. 10, 1001 (2015) [3] J. Urban, Nature Nano. 10, 997 (2015) [4] Jpn. Pat. Appl. JP2016 137453; [5] S.Z. Bisri, et al. Adv. Mater. 25, 4309 (2013) Adv. Mater. 26, 5639 (2014) Figure 1 (a) Schematic diagram on the assembly of PbS QD to form superlattice assembly by crosslinking them with shorter ligands and (b) its HAADF scanning TEM (inset: TEM of individual QD in atomic detail) (c) Application of ionic liquid gating is able to accumulate very high carrier density and tune QD assembly Fermi energy, (d) the ID VG transfer characteristics of PbS QDs shows negative transconductance that indicates the filling of the discrete energy levels. Di 65Hui Ying Yong Wu Li Xue Hui Chun Ji Xue Shu Jiang Yan Hui Jiang Yan Yu Gao Ji (2018 Zao Dao Tian Da Xue Xi Zao Dao Tian kiyanpasu) 17p F210 3", "author_names": [ "Satria Zulkarnaen Bisri", "Maria Ibanez", "Maksym V Kovalenko", "Yoshihiro Iwasa" ], "corpus_id": 125529847, "doc_id": "125529847", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Probing Degeneracy of Discrete Electronic States of Colloidal Quantum Dots", "venue": "", "year": 2018 }, { "abstract": "Colloidal semiconductor nanocrystals, also known as \"quantum dots\" (QDs) represent an example of a disruptive technology for display and lighting applications. Their high luminescence efficiency and tunable, narrow emission are nearly ideal for achieving saturated colors and enriching the display or TV color gamut. Our contribution will discuss the next generation of inorganic nanostructures with electronic structure optimized for achieving emission characteristics beyond traditional near spherical QDs. For example, nano heterostructures with spherical CdSe QDs epitaxially integrated into CdS quantum rods combine high luminescence efficiency with giant extinction coefficients, large Stokes shifts, and linearly polarized emission. Such a set of characteristics can be ideal for LCD backlighting. The other class of emitters includes colloidal quantum wells (QWs) whose ensemble luminescence is significantly narrower than emission spectra of the best QD samples. Moreover, we show that colloidal QWs produce amplified spontaneous emission (ASE) with pump fluence thresholds as low as 6 mJ/cm2 and gain as high as 600 cm 1, on par with the best values for any solution processed material.", "author_names": [ "Chunxing She", "Igor Fedin", "Michael A Boles", "Dmitriy S Dolzhnikov", "Richard D Schaller", "Matthew Pelton", "Dmitri V Talapin" ], "corpus_id": 135544336, "doc_id": "135544336", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "12.2: Invited Paper: Colloidal Quantum Rods and Wells for Lighting and Lasing Applications", "venue": "", "year": 2014 } ]

[ { "abstract": "Over the last 2 decades, power semiconductor technology has made impressive progress by increasing the power density of monolithic and system modules (Trends of power packaging and modeling, 2008; Trends in analog and power packaging, 2009; Challenges of power electronic packaging and modeling, 2011; Short course: analog and power packaging, 2011) This is the primary driving force behind power system in package (SiP) stack die, and 3D power packages with heterogeneous functional integration. For low power ultraportable applications such as mobile phones and the iPad(r) tablet, the most critical requirement for the point of load buck converter is its size. There are several ways to build the buck converter power module. The typical approach is to design the product with die side by side placement in a single level module using a QFN or other standard package, but this method cannot get the benefit of smaller package size. Another way is to build the buck converter with stack die or 3D concept, which may significantly reduce the package size to satisfy the power management for portable application. For high power with hybrid integration, side by side die placement power module is the primary design method for motion control such as automotive, railway, wind energy, and so on.", "author_names": [ "Yong Liu" ], "corpus_id": 59923928, "doc_id": "59923928", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Power Module/SiP/3D/Stack/Embedded Packaging Design and Considerations", "venue": "", "year": 2012 }, { "abstract": "A miniature LTCC system in package (SiP) module has been presented for millimeter wave applications. A typical heterodyne 61 GHz transmitter (Tx) has been designed and fabricated in a type of the SiP module as small as 36 x 12 x 0.9 mm3. Five active chips including a mixer, driver amplifier, power amplifier, and two frequency multipliers were mounted on the single LTCC package substrate, in which all passive circuits such as a stripline (SL) BPF, 2 x 2 array patch antenna, surface mount technology (SMT) pads, and intermediate frequency (IF) feeding lines have been monolithically embedded by using vertical and planar transitions. The embedded SL BPF shows the center frequency of 60.8 GHz, BW of 4.1% and insertion loss of 3.74 dB. The gain and 3 dB beam width of the fabricated 2 x 2 array patch antenna are 7 dBi and 36 degrees, respectively. The assembled LTCC 61 GHz Tx SiP module achieves an output power of 10.2 dBm and an up conversion gain of 7.3 dB. Because of the integrated BPF, an isolation level between a local oscillation (LO) and RF signal is below 26.4 dBc and the spurious level is suppressed by lower than 22.4 dBc. By using a 61 GHz receiver (Rx) consisting of off the shelf modules, wireless communication test was demonstrated by comparing measured IF spectrums at the Tx and Rx part.", "author_names": [ "Young Chul Lee", "Chul Soon Park" ], "corpus_id": 113752825, "doc_id": "113752825", "n_citations": 10, "n_key_citations": 0, "score": 1, "title": "LTCC based monolithic system in package (SiP) module for millimeter wave applications", "venue": "", "year": 2016 }, { "abstract": "Silicon interposers are providing interesting alternatives to organic packages for the fabrication of complex system in package (SIP) modules in particular for RF application. Among the advantages of this technology are the capability to fabricate fine pitch redistribution layers and to embed inside the interposer some high quality passive elements very close to the active chips resulting in a highly integrated solution. To keep the technology at a reasonable cost these last add on features need to be fabricated with no or minor additional process steps that the ones needed for the fabrication of the interposer itself. In this work we present the design and the fabrication of a high resistive silicon interposer conceived for hosting a functional RF SIP transceiver including a Front End Module (FEM) a Dual Band Dual Mode Power Amplifier working at 400 and 900 MHz and some embedded planar and 3D inductors. The interposer consists in symmetrical stack with one thick level of copper RDL on each side of the 200 um thin HR silicon substrate and connected with through silicon via last (TSV last) The inductors are built with no additional metallization level. For the inductors development, a dedicated test vehicle was first designed to study different designs including planar spirals and 3D solenoids and torus. Simulation work was first carried out for dimensioning the structures to target inductance values in the range of 0.5 to 10 nH and high quality factor greater than 20. We present the process used for the fabrication, in particular the realization of the thick copper RDL layers on both sides of the interposer and the of the TSV last module. Physical characterization are presented showing the integrity and the good control of the technology. DC and RF electrical measurements assess the performances achieved for the different inductor variants exhibiting low resistance, constant inductance up to 5 GHz and factor of quality higher than 30. The functional RF transceiver SIP module will be then presented. The architecture is an extremely compact multi chip module composed of four actives CMOS chips (VGA, VCO, modulator and the PA) stacked by flip chip with Cu/SnAg ubumps on the HR silicon interposer and surrounded by a hundred of passive SMD components. With this technology the footprint of the module is reduced by a factor of 2 in comparison with the same module made on a uPCB substrate. The signals and ground are fed through the thick copper RDL lines and the TSVs from LGA pads present on the backside of the interposer for assembly on a test board. Different design configurations are made on the same wafer that include some version using only SMD inductors and some using 2.5 and 3D inductors in order to compare the corresponding performances. Other test structures are also present like filters and individual inductors for DC and RF characterization. We will finally present the resulting performances obtained from this SIP integration.", "author_names": [ "Gabriel Pares", "Michel Jean-Philippe", "Deschaseaux Edouard", "Ferris Pierre", "Serhan Ayssar", "Giry Alexandre" ], "corpus_id": 201741368, "doc_id": "201741368", "n_citations": 4, "n_key_citations": 1, "score": 1, "title": "Highly Compact RF Transceiver Module Using High Resistive Silicon Interposer with Embedded Inductors and Heterogeneous Dies Integration", "venue": "2019 IEEE 69th Electronic Components and Technology Conference (ECTC)", "year": 2019 }, { "abstract": "In this paper, a new structure of power electronic package is addressed. The package structure has high process integration including package assembly and substrate process. Hence, good capability for heterogeneous process integration is very important. To apply the new structure on power SiP module, an integration design of power SiP module that involved an embedded low side MOS (LMOS) an embedded high side MOS (HMOS) and an embedded CMOS controller is demonstrated. The performance of thermal dissipation and power efficiency is better than using power QFN (PQFN) solution. For overall package size, the new structure is also smaller than conventional power package such as PQFN.", "author_names": [ "Hung-Chun Kuo", "P Chen", "C T Chiu", "C C Wang", "Kay S Essig" ], "corpus_id": 40269744, "doc_id": "40269744", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "High efficiency power electronic module with embedded die", "venue": "2016 IEEE CPMT Symposium Japan (ICSJ)", "year": 2016 }, { "abstract": "This paper presents a cost effective area IO DRAM (aDRAM)/logic integration implemented with CLC (chip laminate chip) based system in a package (SiP) technology. By inserting 512 area IOs into the area IO DRAM, the bandwidth of the area IO DRAM can achieve 10GB/s when working under 166MHz. An interface module with configurable IO width was also developed to make this implementation platform able to be adapted by various applications. A performance analysis, including bandwidth and power is also presented in this paper. It is demonstrated that area IO DRAM/logic integration with SiP technology provides significant cost effective implementation methodology compared with embedded DRAM and off chip DRAM.", "author_names": [ "Anru Wang", "Wayne Wei-Ming Dai" ], "corpus_id": 15345580, "doc_id": "15345580", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Area IO DRAM/logic integration with system in a package (SiP)", "venue": "Proceedings of the ASP DAC 2005. Asia and South Pacific Design Automation Conference, 2005.", "year": 2005 }, { "abstract": "The paper presents a cost effective area IO DRAM (aDRAM)/logic integration implemented with CLC (chip laminate chip) based system in a package (SiP) technology. By inserting 512 area IOs into the aDRAM, the bandwidth of the area IO DRAM can achieve 10 GB/s when working under 166 MHz. An interface module with configurable IO width was also developed to make this implementation platform adoptable by various applications. A performance analysis, including bandwidth and power, is also presented. It is demonstrated that area IO DRAM/logic integration with SiP technology provides a significant cost effective implementation methodology compared with embedded DRAM and off chip DRAM.", "author_names": [ "A Wang", "Wayne Wei-Ming Dai" ], "corpus_id": 62059752, "doc_id": "62059752", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and Analysis of Area IO DRAM/Logic Integration with System in a Package(SiP)", "venue": "ISQED", "year": 2005 }, { "abstract": "The paper presents a cost effective area IO DRAM (aDRAM)/logic integration implemented with CLC (chip laminate chip) based system in a package (SiP) technology. By inserting 512 area IOs into the aDRAM, the bandwidth of the area IO DRAM can achieve 10 GB/s when working under 166 MHz. An interface module with configurable IO width was also developed to make this implementation platform adoptable by various applications. A performance analysis, including bandwidth and power, is also presented. It is demonstrated that area IO DRAM/logic integration with SiP technology provides a significant cost effective implementation methodology compared with embedded DRAM and off chip DRAM.", "author_names": [ "Anru Wang", "Wayne Wei-Ming Dai" ], "corpus_id": 2492939, "doc_id": "2492939", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Design and analysis of area IO DRAM/logic integration with system in a package (SiP)", "venue": "Sixth international symposium on quality electronic design (isqed'05)", "year": 2005 }, { "abstract": "This paper presents a compact multi channel receiver front end using system in package (SiP) integration technology. In the circuit linking design, a power divider network is introduced to keep the amplitude consistency of the local oscillator (LO) signal for each channel. The embedded low temperature co fired ceramic (LTCC) RF filter equipped with two transmission zeros is developed by using substrate integrated waveguide (SIW) technology and its design and tuning techniques are discussed. Based on a viable LTCC SiP structure and micro packaging technology, the receiver front end module is fabricated and all the functional devices are integrated on a single substrate. The measured results indicate that the module has high selectivity as well as the great conversion gain and low noise figure of 50 dB and 2.8 dB respectively. The overall size of the three channel module is about 36 mm x23 mm x 3 mm.", "author_names": [ "Yujin Zhou", "Anfeng Sun", "Jun Zhou", "Ya Shen" ], "corpus_id": 18561598, "doc_id": "18561598", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "A compact multi channel receiver front end using SiP integration technology on LTCC substrate for wireless communications", "venue": "2015 International Conference on Wireless Communications Signal Processing (WCSP)", "year": 2015 }, { "abstract": "In this paper, using low temperature co fired ceramic(LTCC) based system in package(SiP) technology, a very compact power amplifier LTCC module was designed, fabricated, and then characterized for 60 GHz wireless transmitter applications. In order to reduce the interconnection loss between a LTCC board and power amplifier monolithic microwave integrated circuits(MMIC) bond wire transitions were optimized and high isolated module structure was proposed to integrate the power amplifier MMIC into LTCC board. In the case of wire bonding transition, a matching circuit was designed on the LTCC substrate and interconnection space between wires was optimized in terms of their angle. In addition, the wire bonding structure of coplanar waveguide type was used to reduce radiation of EM fields due to interconnection discontinuity. For high isolated module structure, DC bias lines were fully embedded into the LTCC substrate and shielded with vias. Using 5 layer LTCC dielectrics, the power amplifier LTCC module was fabricated and its size is The fabricated module shows the gain of 10 dB and the output power of 11 dBm at P1dB compression point from 60 to 65 GHz.", "author_names": [ "Young-Chul Lee" ], "corpus_id": 107392155, "doc_id": "107392155", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Very Compact 60 GHz LTCC Power Amplifier Module", "venue": "", "year": 2006 }, { "abstract": "This paper brings into light the first prototype miniaturized system in package (SiP) Microsystems built for wireless body area network medical devices which mandate low power consumption and extreme packaging miniaturization. Specifically, this paper focuses on the scenario for a 3D SiP module for wearable demonstrators, namely hearing aids and insulin pups, with an active antenna integrated on top of the individual 2D SiPs. The whole 3D SiP is assembled on the end user device PCB. The presented paper describes in detail all manufacturing steps for the realization of the 3D SiP and all technology developments achieved to reach this goal. Firstly, a 2 layer SiP substrate has been successfully produced with 35 mm ultra fine line copper structuring in conjunction with 100 mm blind vias using semi additive technology. Subsequently, assembly technologies for heterogeneous BAN components were further developed in order to achieve the placement of the tiny IF SAW filters and BAW resonators on the substrate and to implement mixed assembly of soldered passives with fluxed chip packages. Finally, the paper highlights the embedding technology employed in the project for the manufacturing of 3D SiP modules on 9\"x12\" large panels, as well as the stacking technology for the realization of the 3D SiP microsystems. The whole 3D SiP module has a very small size of 3.48 mm x 3.48 mm x 1.5 mm.", "author_names": [ "Dionysios Manessis", "A Podlasly", "Andreas Ostmann", "Rolf Aschenbrenner", "Klaus-D Lang" ], "corpus_id": 11780434, "doc_id": "11780434", "n_citations": 4, "n_key_citations": 2, "score": 1, "title": "Large scale manufacturing of embedded subsystems in substrates and a 3D stacking approach for a miniaturised medical system integration", "venue": "2013 Eurpoean Microelectronics Packaging Conference (EMPC)", "year": 2013 } ]

[ { "abstract": "Semiconductors in all dimensionalities ranging from 0D quantum dots and molecules to 3D bulk crystals support bound electron hole pair quasiparticles termed excitons. Over the past two decades, the emergence of a variety of low dimensional semiconductors that support excitons combined with advances in nano optics and photonics has burgeoned an advanced area of research that focuses on engineering, imaging, and modulating the coupling between excitons and photons, resulting in the formation of hybrid quasiparticles termed exciton polaritons. This advanced area has the potential to bring about a paradigm shift in quantum optics, as well as classical optoelectronic devices. Here, we present a review on the coupling of light in excitonic semiconductors and previous investigations of the optical properties of these hybrid quasiparticles via both far field and near field imaging and spectroscopy techniques. Special emphasis is given to recent advances with critical evaluation of the bottlenecks that plague various materials toward practical device implementations including quantum light sources. Our review highlights a growing need for excitonic material development together with optical engineering and imaging techniques to harness the utility of excitons and their host materials for a variety of applications.", "author_names": [ "S B Anantharaman", "Kiyoung Jo", "Deep Jariwala" ], "corpus_id": 232046017, "doc_id": "232046017", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Exciton Photonics: From Fundamental Science to Applications.", "venue": "ACS nano", "year": 2021 }, { "abstract": "Cette these etudie le faconnage de champs electromagnetiques micro ondes dans des cavites presentant des conditions aux limites reconfigurables. Le dispositif experimental s'appuie sur une metasurface electroniquement reconfigurable qui couvre partialement les parois d'une cavite et qui permet ainsi de controler la facon dont les ondes y sont reflechies. Le premier chapitre explore des aspects fondamentaux. D'abord, une etude parametrique du faconnage d'un champ d'ondes electromagnetiques monochromatique et stationnaire en cavite est proposee en fonction d'un degre de controle introduit. Selon la valeur de ce parametre, il est possible de concentrer de l'energie en un endroit donne de la cavite de facon predictible, de reconfigurer totalement cette cavite, ou bien de decider d'obtenir une resonance a une frequence qui n'en supportait pas auparavant. Ensuite, l'imposition d'un comportement chaotique a une cavite de geometrie reguliere est demontree et une application au brassage des modes en chambre reverberante est donnee. Dans la suite, la possibilite d'ajuster le couplage antenne cavite est abordee, et une adaptation parfaite et dynamiquement configurable de l'impedance est proposee. Le reste du premier chapitre considere des champs transitoires. Dans un premier temps, la focalisation spatio temporelle d'une impulsion fortement reverberee dans une cavite en utilisant uniquement le controle spatial des ondes offert par la metasurface est demontree, puis le lien avec le couplage entre les degrees de liberte spatiaux et temporels du milieu de propagation est fait. Enfin, un dispositif permettant la reconfiguration repetee des conditions aux limites d'une cavite en un laps de temps inferieur au temps de vie des photons est realise, et des resultats preliminaires sont montres. Dans le deuxieme chapitre, des applications aux systemes de communication sans fil multi utilisateurs sont proposees. D'abord, dans la limite d'un bas facteur de qualite de la cavite, il est montre qu'un formalisme matriciel permet de decrire l'impact de la metasurface sur le champ. Cette matrice, mesuree sans information de phase, permet alors de focaliser le champ sur une ou plusieurs positions simultanement. Ensuite, la possibilite d'obtenir une diversite de canaux optimale (orthogonalite des canaux) en faconnant idealement le desordre d'un milieu de propagation a l'aide de metasurfaces est etablie. Finalement, le formalisme matriciel est utilise afin d'introduire un concept de calcul analogique realise par le milieu desordonne en faconnant le front d'onde incident. Il est des lors conclu qu'avec une infrastructure standard de Wi Fi dans une maison, en combinaison avec une metasurface simple, cette idee peut etre implementee. Le concept est enfin transpose au domaine optique avec une fibre multimode. Au cours du troisieme chapitre, quelques applications du faconnage d'ondes en milieux reverberants aux capteurs des environnements connectes sont etudiees. D'abord, la possibilite de concentrer des champs electromagnetiques ambients sur des circuits redresseurs afin d'obtenir des tensions de sortie utiles est demontree. De plus, grace aux non linearites intrinseques du redresseur, ceci est possible meme sans avoir un retour direct du redresseur sur l'intensite du champ incident. Ensuite, un detecteur de mouvement hors ligne de vue et intelligent est propose, qui profite d'un co design de sa couche physique et du traitement de donnees. Enfin, il est demontre que meme des objets non cooperatifs dans un environnement complexe peuvent etre localises grace a leur contribution a la diffusion des ondes dans ledit milieu. L'equivalence d'utiliser la diversite frequentielle ou bien le faconnage d'ondes dans ce contexte est etablie.", "author_names": [ "del Hougne", "Marc Philipp" ], "corpus_id": 126150139, "doc_id": "126150139", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Shaping Green's Functions in Cavities with Tunable Boundary Conditions From Fundamental Science to Applications", "venue": "", "year": 2018 }, { "abstract": "", "author_names": [], "corpus_id": 199492584, "doc_id": "199492584", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Nanoscale Zerovalent Iron Particles for Environmental Restoration: From Fundamental Science to Field Scale Engineering Applications", "venue": "", "year": 2019 }, { "abstract": "Academia and industry alike are faced with an ever growing demand for energy efficiency and reduced mass", "author_names": [ "Martin F -X Wagner" ], "corpus_id": 139191755, "doc_id": "139191755", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Light Weight Aluminum Based Alloys From Fundamental Science to Engineering Applications", "venue": "", "year": 2018 }, { "abstract": "Moore's law predicts the exponential development of computing systems based on silicon materials and binary algorithms. This imposes high pressure on further component miniaturization and the speed of operation, a trend that challenges the limits of the current technological advance. Conceptually novel ideas and thinking outside the box are needed to overcome these limitations. In this context, the creativity of researchers working at the intersection of chemistry, biology, and physics has opened up several exciting paths in the general area of unconventional computing, including quantum computing and biologically inspired molecular computing. Molecular computing systems, even though they are often motivated by information processing in nature, are not necessarily based on biomolecules and can be equally integrated in tailor made synthetic molecules with stimuli controlled switchable properties. Synthetic molecular systems and nanoscale supramolecular materials have been designed to mimic the operation of Boolean logic gates and demonstrate basic arithmetic and memory functions using light, chemicals, or electrochemistry to address and read them. However, despite the unquestionable progress that has been made in the last fifteen years regarding several practical aspects such as recycled operation, long term stability, and concatenation, the further increase of their complexity is very challenging. Interesting advances in the development of molecular information processing have been achieved with the use of biomolecules, such as DNA/ RNA, proteins/enzymes, and even whole biological cells, conjugating the field with ideas from systems biology. An advantage of the biomolecular computing systems is their ability to be integrated in artificially designed complex chemical processes mimicking multi step information processing networks. These systems are still far away from the efficient and robust information processing in cells, but constitute certainly a viable strategy towards higher complexity. In fact, biochemical reactions are at the core of the mechanism of life itself, and therefore one could set rather ambitious expectations for how far (bio)chemical systems can be scaled up in complexity, if not speed, for information processing.", "author_names": [ "Engin U Akkaya", "Evgeny Katz", "Uwe Pischel" ], "corpus_id": 3442312, "doc_id": "3442312", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Molecular Logic: From Single Logic Gates to Sophisticated Logic Circuits, from Fundamental Science to Practical Applications.", "venue": "Chemphyschem a European journal of chemical physics and physical chemistry", "year": 2017 }, { "abstract": "1. Regulation and delivery of neurotrophins 28 1.1. Regulation of BDNF expression 28 1.2. Regulation of BDNF release/delivery 28 2. Neurotrophins in development and growth. .29 3. Neurotrophins in synaptic transmission and plasticity 29 3.1. Pre synaptic modulation 29 3.2. Synaptic plasticity and learning .30 4. Neurotrophins in disease 31 4.1. Autism spectrum disorders 31 4.2. Obesity. .31 4.3. OCD 31 4.4. Addiction 32 4.5. Neurodegenerative disorders 32 5. Translational advances. .32 6. Closing remarks 33 Acknowledgements .33 References 33", "author_names": [ "Joshua L Plotkin", "Chengbiao Wu" ], "corpus_id": 40897142, "doc_id": "40897142", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Neurotrophin biology at NGF 2016: From fundamental science to clinical applications", "venue": "International Journal of Developmental Neuroscience", "year": 2017 }, { "abstract": "This reference book originates from the interdisciplinary research cooperation between academia and industry. In three distinct parts, latest results from basic research on stable enzymes are explained and brought into context with possible industrial applications. Downstream processing technology as well as biocatalytic and biotechnological production processes from global players display the enormous potential of biocatalysts. Application of \"extreme\" reaction conditions (i.e. unconventional, such as high temperature, pressure, and pH value) biocatalysts are normally used within a well defined process window leads to novel synthetic effects. Both novel enzyme systems and the synthetic routes in which they can be applied are made accessible to the reader. In addition, the complementary innovative process technology under unconventional conditions is highlighted by latest examples from biotech industry.", "author_names": [ "Lutz Hilterhaus", "Andreas Liese", "Ulrich Kettling", "Garabed Antranikian" ], "corpus_id": 114697299, "doc_id": "114697299", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Applied Biocatalysis: From Fundamental Science to Industrial Applications: From Fundamental Science to Industrial Applications", "venue": "", "year": 2016 }, { "abstract": "Resonance energy transfer (RET) the transport of electronic energy from one atom or molecule to another, has significant importance to a number of diverse areas of science. Since the pioneering experiments on RET by Cario and Franck in 1922, the theoretical understanding of the process has been continually refined. This review presents a historical account of the post Forster outlook on RET, based on quantum electrodynamics, up to the present day viewpoint. It is through this quantum framework that the short range, R 6 distance dependence of Forster theory was unified with the long range, radiative transfer governed by the inverse square law. Crucial to the theoretical knowledge of RET is the electric dipole electric dipole coupling tensor; we outline its mathematical derivation with a view to explaining some key physical concepts of RET. The higher order interactions that involve magnetic dipoles and electric quadrupoles are also discussed. To conclude, a survey is provided on the latest research, which includes transfer between nanomaterials, enhancement due to surface plasmons, possibilities outside the usual ultraviolet or visible range and RET within a cavity.", "author_names": [ "Garth A Jones", "David S Bradshaw" ], "corpus_id": 195877350, "doc_id": "195877350", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "Resonance Energy Transfer: From Fundamental Theory to Recent Applications", "venue": "Front. Phys.", "year": 2019 }, { "abstract": "Metallo oxide (MO) based bioinorganic nanocomposites promise unique structures, physicochemical properties, and novel biochemical functionalities, and within the past decade, investment in research on materials such as ZnO, TiO2, SiO2, and GeO2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning, and postprocessing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science. Practically, we need an effective defragmentation of the research area. From our perspective, the superficial accounting of material properties, chemistry of the surfaces, and the behavior of biomolecules next to such surfaces is a problem. This is particularly of concern when we wish to bridge between technologies in vitro and biotechnologies in vivo. Further, besides the potential practical technological efficiency and advantages such materials might exhibit, we have to consider the wider long term implications of material stability and toxicity. In this contribution, we present a critical review of recent advances in the chemistry and engineering of MO based biocomposites, highlighting the role of interactions at the interface and the techniques by which these can be studied. At the end of the article, we outline the challenges which hamper progress in research and extrapolate to developing and promising directions including additive manufacturing and synthetic biology that could benefit from molecular level understanding of interactions occurring between inanimate (abiotic) and living (biotic) materials.", "author_names": [ "Marion J Limo", "Anna Sola-Rabada", "Estefania Boix", "Veeranjaneyulu Thota", "Zayd C Westcott", "Valeria Puddu", "Carole C Perry" ], "corpus_id": 206541649, "doc_id": "206541649", "n_citations": 68, "n_key_citations": 0, "score": 0, "title": "Interactions between Metal Oxides and Biomolecules: from Fundamental Understanding to Applications.", "venue": "Chemical reviews", "year": 2018 }, { "abstract": "Optical forces, generally arising from changes of field gradients or linear momentum carried by photons, form the basis for optical trapping and manipulation. Advances in optical forces help to reveal the nature of light matter interactions, giving answers to a wide range of questions and solving problems across various disciplines, and are still yielding new insights in many exciting sciences, particularly in the fields of biological technology, material applications, and quantum sciences. This review focuses on recent advances in optical forces, ranging from fundamentals to applications for biological exploration. First, the basics of different types of optical forces with new light matter interaction mechanisms and near field techniques for optical force generation beyond the diffraction limit with nanometer accuracy are described. Optical forces for biological applications from in vitro to in vivo are then reviewed. Applications from individual manipulation to multiple assembly into functional biophotonic probes and soft matter superstructures are discussed. At the end future directions for application of optical forces for biological exploration are provided.", "author_names": [ "Hongbao Xin", "Yuchao Li", "Yong-Chun Liu", "Yao Zhang", "Yun-Feng Xiao", "Baojun Li" ], "corpus_id": 220796325, "doc_id": "220796325", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Optical Forces: From Fundamental to Biological Applications.", "venue": "Advanced materials", "year": 2020 } ]

[ { "abstract": "An improved charger for electric vehicle with bridgeless PFC (Power Factor Correction) SEPIC (Single Ended Primary Inductor) converter topology is designed and discussed in this paper, which cascades a flyback converter to control the charging. The main disadvantage of PFC SEPIC converter is the high current stress across the output capacitor as a diode is present at the output. Therefore, these converters are restricted to the low power applications. The proposed converter overcomes the above limitation as the gain of proposed converter is doubled which results into reduced stress across the output capacitors. The voltage stress across the semiconductor device is considerably reduced for the same output voltage level due to high converter gain and lower duty cycle required for proposed converter as compared to conventional converter. The flyback converter controls the charging in constant current (CC) and constant voltage charging (CV) modes. Both the converters are designed to operate in discontinuous mode (DCM) which eliminates the need for input current sensor and inherent zero current switching for the converters is achieved. A prototype is developed and tested to verify the effectiveness of charger to conform the PQ regulations such as IEC 61000 3 2, at steady state and at wide varying source rms voltages.", "author_names": [ "Radha Kushwaha", "Bhim Singh" ], "corpus_id": 216043927, "doc_id": "216043927", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "An Improved PFC Bridgeless SEPIC Converter for Electric Vehicle Charger", "venue": "2020 IEEE International Conference on Power Electronics, Smart Grid and Renewable Energy (PESGRE2020)", "year": 2020 }, { "abstract": "In this paper, a systematic review of bridgeless power factor correction (PFC) boost rectifiers, also called dual boost PFC rectifiers, is presented. Performance comparison between the conventional PFC boost rectifier and a representative member of the bridgeless PFC boost rectifier family is performed. Loss analysis and experimental efficiency evaluation for both CCM and DCM/CCM boundary operations are provided.", "author_names": [ "Laszlo Huber", "Yungtaek Jang", "Milan M Jovanovic" ], "corpus_id": 7017824, "doc_id": "7017824", "n_citations": 665, "n_key_citations": 34, "score": 0, "title": "Performance Evaluation of Bridgeless PFC Boost Rectifiers", "venue": "IEEE Transactions on Power Electronics", "year": 2008 }, { "abstract": "The goal of this paper is to study the possibility of minimizing common mode (CM) noise emission in bridgeless power factor correction (PFC) converters. Two approaches are proposed. In the first approach, the bridgeless PFC is modified to achieve symmetry. A CM noise model for symmetric topology is derived and the conditions for symmetry are summarized. Parasitics critical to the symmetrical condition are studied and carefully controlled. As a result, CM noise can be minimized with good cancellation. The second approach is to introduce a balance technique to bridgeless PFC converters. The topology is modified so that the balance technique can be applied so as to minimize CM noise. Experimental results validate that both approaches can greatly reduce CM noise up to 30 dBmuV. The two approaches are compared in terms of both its effects on CM noise and their implementations.", "author_names": [ "Pengju Kong", "Shuo Wang", "Fred C Lee" ], "corpus_id": 12859216, "doc_id": "12859216", "n_citations": 195, "n_key_citations": 11, "score": 0, "title": "Common Mode EMI Noise Suppression for Bridgeless PFC Converters", "venue": "IEEE Transactions on Power Electronics", "year": 2008 }, { "abstract": "Hybrid electric vehicle (HEV) technology provides an effective solution for achieving higher fuel economy, better performance, and lower emissions, compared with conventional vehicles. Plug in HEVs (PHEVs) are HEVs with plug in capabilities and provide a more all electric range; hence, PHEVs improve fuel economy and reduce emissions even more. PHEVs have a battery pack of high energy density and can run solely on electric power for a given range. The battery pack can be recharged by a neighborhood outlet. In this paper, a novel integrated bidirectional AC/DC charger and DC/DC converter (henceforth, the integrated converter) for PHEVs and hybrid/plug in hybrid conversions is proposed. The integrated converter is able to function as an AC/DC battery charger and to transfer electrical energy between the battery pack and the high voltage bus of the electric traction system. It is shown that the integrated converter has a reduced number of high current inductors and current transducers and has provided fault current tolerance in PHEV conversion.", "author_names": [ "Young-Joo Lee", "Alireza Khaligh", "Ali Emadi" ], "corpus_id": 29078144, "doc_id": "29078144", "n_citations": 394, "n_key_citations": 18, "score": 0, "title": "Advanced Integrated Bidirectional AC/DC and DC/DC Converter for Plug In Hybrid Electric Vehicles", "venue": "IEEE Transactions on Vehicular Technology", "year": 2009 }, { "abstract": "Solid state switch mode rectification converters have reached a matured level for improving power quality in terms of power factor correction (PFC) reduced total harmonic distortion at input ac mains and precisely regulated dc output in buck, boost, buck boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched mode ac dc converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.", "author_names": [ "Bhim Singh", "Brij N Singh", "Ambrish Chandra", "Kamal Al-Haddad", "Ashish Pandey", "Dwarkadas Pralhaddas Kothari" ], "corpus_id": 8289994, "doc_id": "8289994", "n_citations": 1016, "n_key_citations": 34, "score": 0, "title": "A review of single phase improved power quality AC DC converters", "venue": "IEEE Trans. Ind. Electron.", "year": 2003 }, { "abstract": "In this paper, a new front end ac dc bridgeless interleaved power factor correction topology is proposed for level II plug in hybrid electric vehicle (PHEV) battery charging. The topology can achieve high efficiency, which is critical for minimizing the charger size, PHEV charging time and the amount and cost of electricity drawn from the utility. In addition, a detailed analytical model for this topology is presented, enabling the calculation of the converter power losses and efficiency. Experimental and simulation results are included for a prototype boost converter converting universal ac input voltage (85 265 V) to 400 V dc output at up to 3.4 kW load. The experimental results demonstrate a power factor greater than 0.99 from 750 W to 3.4 kW, THD less than 5% from half load to full load and a peak efficiency of 98.9% at 70 kHz switching frequency, 265 V input and 1.2 kW load.", "author_names": [ "Fariborz Musavi", "Wilson Eberle", "William G Dunford" ], "corpus_id": 8737494, "doc_id": "8737494", "n_citations": 294, "n_key_citations": 9, "score": 0, "title": "A High Performance Single Phase Bridgeless Interleaved PFC Converter for Plug in Hybrid Electric Vehicle Battery Chargers", "venue": "IEEE Transactions on Industry Applications", "year": 2011 }, { "abstract": "This article presents an improved power quality Cuk converter fed isolated LLC resonant converter for an electric vehicle battery charger (EVBC) intended typically to charge a small two or three wheel driven electric vehicle (EV) using up to 20 Ah battery. The proposed topology consists of two converters, comprising of the first stage for power factor correction (PFC) and the second stage for effective charging of the EV battery using a constant voltage and constant current mode control algorithm. In the first stage, the Cuk converter performs PFC by operating in the continuous conduction mode of the primary inductor, while the LLC resonant converter converts the dc link voltage to the isolated dc voltage required for the EVBC. The proposed converter uses a frequency control algorithm to actively vary the intermediate dc link voltage based on the state of charge of the battery leading to reduced turn off losses in the LLC converter switching devices. The proposed converter is designed and simulated in MATLAB. Simulated results are analyzed and discussed in detail. Finally, a 580 W 10 A experimental prototype of the EVBC is developed, and test results are presented to demonstrate the effectiveness of the proposed topology. The proposed converter exhibits excellent power quality indices adhering to the IEC 61000 3 2 international standard.", "author_names": [ "Rahul Pandey", "Bhim Singh" ], "corpus_id": 202100549, "doc_id": "202100549", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "A Power Factor Corrected LLC Resonant Converter for Electric Vehicle Charger Using Cuk Converter", "venue": "IEEE Transactions on Industry Applications", "year": 2019 }, { "abstract": "This paper presents a power factor corrected (PFC) bridgeless (BL) buck boost converter fed brushless direct current (BLDC) motor drive as a cost effective solution for low power applications. An approach of speed control of the BLDC motor by controlling the dc link voltage of the voltage source inverter (VSI) is used with a single voltage sensor. This facilitates the operation of VSI at fundamental frequency switching by using the electronic commutation of the BLDC motor which offers reduced switching losses. A BL configuration of the buck boost converter is proposed which offers the elimination of the diode bridge rectifier, thus reducing the conduction losses associated with it. A PFC BL buck boost converter is designed to operate in discontinuous inductor current mode (DICM) to provide an inherent PFC at ac mains. The performance of the proposed drive is evaluated over a wide range of speed control and varying supply voltages (universal ac mains at 90 265 V) with improved power quality at ac mains. The obtained power quality indices are within the acceptable limits of international power quality standards such as the IEC 61000 3 2. The performance of the proposed drive is simulated in MATLAB/Simulink environment, and the obtained results are validated experimentally on a developed prototype of the drive.", "author_names": [ "Vashist Bist", "Bhim Singh" ], "corpus_id": 22292282, "doc_id": "22292282", "n_citations": 177, "n_key_citations": 15, "score": 0, "title": "An Adjustable Speed PFC Bridgeless Buck Boost Converter Fed BLDC Motor Drive", "venue": "IEEE Transactions on Industrial Electronics", "year": 2014 }, { "abstract": "Batteries of Electric Vehicles (EVs) and Plug in Hybrid Electric Vehicles (PHEVs) have a large potential not only to provide energy for the locomotion of these vehicles, but also to interact, in dynamic way, with the power grid. Thereby, through the energy stored in the batteries, these vehicles can be used to regulate the active and the reactive power, as local Energy Storage Systems. This way, EVs can contribute to help the power grid to regulate the active and reactive power flow in order to stabilize the production and consumption of energy. For this propose should be defined usage profiles, controlled by a collaborative broker, taking into account the requirements of the power grid and the conveniences of the vehicle user. Besides, the interface between the power grid and the EVs, instead of using typical power converters that only work on unidirectional mode, need to use bidirectional power converters to charge the batteries (G2V Grid to Vehicle mode) and to deliver part of the stored energy in the batteries back to the power grid (V2G Vehicle to Grid mode) With the bidirectional power converter topology presented in this paper, the consumed current is sinusoidal and it is possible to regulate the power factor to control the reactive power, aiming to contribute to mitigate power quality problems in the power grid. To assess the behavior of the presented bidirectional power converter under different scenarios, are presented some computer simulations and experimental results obtained with a prototype that was developed to be integrated in an Electric Vehicle.", "author_names": [ "Vitor Monteiro", "Jose Gabriel Pinto", "Bruno Exposto", "Henrique Goncalves", "Joao C Ferreira", "Carlos Couto", "Joao Luiz Afonso" ], "corpus_id": 19593060, "doc_id": "19593060", "n_citations": 67, "n_key_citations": 1, "score": 0, "title": "Assessment of a battery charger for Electric Vehicles with reactive power control", "venue": "IECON 2012 38th Annual Conference on IEEE Industrial Electronics Society", "year": 2012 }, { "abstract": "A new modulated carrier control (MCC) method is proposed in this paper for a power factor correction (PFC) boost converter, which provides high power factor (PF) and low total harmonic distortion (THD) in wide input voltage and load range. The proposed MCC method employs a zero current duration (ZCD) demodulator that detects ZCD in each switching cycle to estimate current conduction duration of the boost inductor. Using the estimated signal of the ZCD demodulator, the proposed controller generates a compensated duty signal with a PFC converter to properly operate in continuous conduction mode (CCM) or discontinuous conduction mode (DCM) Unlike the conventional MCC PFC converter where the line current is distorted in DCM resulting in poor PF and high THD, the proposed MCC method can provide higher PFC performance regardless of CCM and DCM while maintaining the simple control loop of conventional MCC control method that does not require inner current loop and using relatively small inductance. In this paper, the operational principle of the proposed method has been discussed. To verify the proposed method, it has been tested on a 400 W PFC boost converter.", "author_names": [ "Jintae Kim", "Hang-Seok Choi", "Chung-Yuen Won" ], "corpus_id": 3481684, "doc_id": "3481684", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "New Modulated Carrier Controlled PFC Boost Converter", "venue": "IEEE Transactions on Power Electronics", "year": 2018 } ]

[ { "abstract": "We investigate photoluminescence from individual \"giant\" CdSe/CdS core/thick shell quantum dots (gQDs) placed near an epitaxial Ag film with an atomically smooth surface. The key observation is that the lifetimes of the gQDs are drastically reduced and exhibit a remarkably narrow distribution compared to the gQDs deposited on a thermally deposited Ag film. The larger variations in gQDs' lifetimes on the thermally deposited Ag film arise from excitonic coupling to localized surface plasmons associated with nanoscale surface corrugations of different heights. A calculation is performed based on a simple model system of a QD coupled to a metallic nanosphere. The calculation shows that the QD lifetime initially shortens and reaches a saturated value with increasing radius of the metal nanoparticle (MNP) Because the epitaxial film can be treated as a sphere with an infinitely large radius, the calculation confirms and explains the different QD dynamics near the two types of Ag films as observed experimentally.", "author_names": [ "Thomas Hartsfield", "Michael Gegg", "Ping-Hsiang Su", "Matthew R G Buck", "Jennifer Ann Hollingsworth", "Chih-Kang Shih", "Marten Richter", "Han Htoon", "Xiaoqin Li" ], "corpus_id": 34113455, "doc_id": "34113455", "n_citations": 11, "n_key_citations": 0, "score": 1, "title": "Semiconductor Quantum Dot Lifetime Near an Atomically Smooth Ag Film Exhibits a Narrow Distribution", "venue": "", "year": 2016 }, { "abstract": "All solution processed inverted quantum dot light emitting diodes (QLEDs) are promising candidates for lighting and display applications. While the external quantum efficiency of inverted devices is comparable to that of devices with normal structure, achieving both high efficiency and long lifetime in such inverted devices remains challenging. Herein, we report an all solution processed inverted green QLED capable of achieving a 96.42 cd A 1 current efficiency, a 25.04% external quantum efficiency, and a 4943.6 h half lifetime. This external quantum efficiency exceeds reported literature values, and the lifetime is over 19 times greater than those of previously reported all solution processed inverted QLEDs. Such excellent performance is attributed to the precisely controlled double ZnS shells of CdSeZnS/ZnS/ZnS quantum dots, which can effectively suppress Auger recombination and Forster resonance energy transfer, as well as decrease efficiency roll off at high driving currents. Overall, this study suggests that shell engineering of quantum dots may provide an effective means of accelerating the inverted QLEDs to meet requirements for practical display and lighting applications.", "author_names": [ "Zhiwen Yang", "Qianqian Wu", "Gongli Lin", "Xiaochuan Zhou", "Weijie Wu", "Xuyong Yang", "Jianhua Zhang", "Li Wanwan" ], "corpus_id": 202215197, "doc_id": "202215197", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "All solution processed inverted green quantum dot light emitting diodes with concurrent high efficiency and long lifetime", "venue": "", "year": 2019 }, { "abstract": "We investigate the impact of threading dislocation density on the reliability of 1.3 mm InAs quantum dot lasers epitaxially grown on Si. A reduction in the threading dislocation density from 2.8 x 108 cm 2 to 7.3 x 106 cm 2 has improved the laser lifetime by about five orders of magnitude when aged continuous wave near room temperature (35 degC) We have achieved extrapolated lifetimes (time to double initial threshold) more than 10 x 106 h. An accelerated laser aging test at an elevated temperature (60 degC) reveals that p modulation doped quantum dot lasers on Si retain superior reliability over unintentionally doped ones. These results suggest that epitaxially grown quantum dot lasers could be a viable approach to realize a reliable, scalable, and efficient light source on Si.", "author_names": [ "Daehwan Jung", "Robert Herrick", "Justin C Norman", "Katherine Turnlund", "Catherine Jan", "Kaiyin Feng", "Arthur C Gossard", "John E Bowers" ], "corpus_id": 44098323, "doc_id": "44098323", "n_citations": 82, "n_key_citations": 4, "score": 0, "title": "Impact of threading dislocation density on the lifetime of InAs quantum dot lasers on Si", "venue": "", "year": 2018 }, { "abstract": "Establishing a highly efficient photon emitter interface where the intrinsic linewidth broadening is limited solely by spontaneous emission is a key step in quantum optics. It opens a pathway to coherent light matter interaction for, e.g. the generation of highly indistinguishable photons, few photon optical nonlinearities, and photon emitter quantum gates. However, residual broadening mechanisms are ubiquitous and need to be combated. For solid state emitters charge and nuclear spin noise are of importance, and the influence of photonic nanostructures on the broadening has not been clarified. We present near lifetime limited linewidths for quantum dots embedded in nanophotonic waveguides through a resonant transmission experiment. It is found that the scattering of single photons from the quantum dot can be obtained with an extinction of 66 4% which is limited by the coupling of the quantum dot to the nanostructure rather than the linewidth broadening. This is obtained by embedding the quantum dot in an electrically contacted nanophotonic membrane. A clear pathway to obtaining even larger single photon extinction is laid out; i.e. the approach enables a fully deterministic and coherent photon emitter interface in the solid state that is operated at optical frequencies.", "author_names": [ "Henri Thyrrestrup", "Gabija Kirsanske", "Hanna Le Jeannic", "Tommaso Pregnolato", "Liang-Jun Zhai", "Laust Raahauge", "Leonardo Midolo", "Nir Rotenberg", "Alisa Javadi", "Rudiger Schott", "Andreas Dirk Wieck", "Arne Ludwig", "Matthias Christian Lobl", "Immo Sollner", "Richard John Warburton", "Peter Lodahl" ], "corpus_id": 3845499, "doc_id": "3845499", "n_citations": 40, "n_key_citations": 1, "score": 0, "title": "Quantum Optics with Near Lifetime Limited Quantum Dot Transitions in a Nanophotonic Waveguide.", "venue": "Nano letters", "year": 2018 }, { "abstract": "We investigate the magnetic field and temperature dependence of the single electron spin lifetime in silicon quantum dots and find a lifetime of 2.8 ms at a temperature of 1.1 K. We develop a model based on spin valley mixing and find that Johnson noise and two phonon processes limit relaxation at low and high temperature, respectively. We also investigate the effect of temperature on charge noise and find a linear dependence up to 4 K. These results contribute to the understanding of relaxation in silicon quantum dots and are promising for qubit operation at elevated temperatures.", "author_names": [ "L Petit", "J M Boter", "H G J Eenink", "Gabriel Droulers", "Marco Lorenzo Valerio Tagliaferri", "R Li", "David P Franke", "K J Singh", "James S Clarke", "R N Schouten", "Viatcheslav V Dobrovitski", "Lieven M K Vandersypen", "Menno Veldhorst" ], "corpus_id": 52141686, "doc_id": "52141686", "n_citations": 58, "n_key_citations": 3, "score": 0, "title": "Spin Lifetime and Charge Noise in Hot Silicon Quantum Dot Qubits.", "venue": "Physical review letters", "year": 2018 }, { "abstract": "High performance III V quantum dot lasers monolithically grown on Si substrates have been demonstrated as a promising solution to realize Si based laser sources with very low threshold current density, high output power, and long lifetime, even with relatively high density of defects due to the material dissimilarities between III Vs and Si. On the other hand, although conventional III V quantum well lasers grown on Si have been demonstrated after great efforts worldwide for more than 40 years, their practicality is still a great challenge because of their very high threshold current density and very short lifetime. However, the physical mechanisms behind the superior performance of silicon based III V quantum dot lasers remain unclear. In this paper, we directly compare the performance of a quantum well and a quantum dot laser monolithically grown on on axis Si (001) substrates, both experimentally and theoretically, under the impact of the same density of threading dislocations. A quantum dot laser grown on a Si substrate with a high operating temperature (105 degC) has been demonstrated with a low threshold current density of 173 A/cm2 and a high single facet output power >100 mW at room temperature, while there is no lasing operation for the quantum well device at room temperature even at high injection levels. By using a rate equation travelling wave model, the quantum dot laser's superior performance compared with its quantum well based counterpart on Si is theoretically explained in terms of the unique properties of quantum dots, i.e. efficient carrier capture and high thermal energy barriers preventing the carriers from migrating into defect states.", "author_names": [ "Zizhuo Liu", "Mickael Martin", "Thierry Baron", "Siming Chen", "Alwyn J Seeds", "Richard Vincent Penty", "Ian H White", "Huiyun Liu", "Constanze Hantschmann", "Mingchu Tang", "Ying Lu", "Jae-Seong Park", "Mengya Liao", "Shujie Pan", "Ana M Sanchez", "Richard Beanland" ], "corpus_id": 198472444, "doc_id": "198472444", "n_citations": 22, "n_key_citations": 2, "score": 0, "title": "Origin of Defect Tolerance in InAs/GaAs Quantum Dot Lasers Grown on Silicon", "venue": "Journal of Lightwave Technology", "year": 2020 }, { "abstract": "Quantum dots are increasingly used in displays to achieve high color gamut at high efficiency. This paper describes the impact of quantum dot lifetime on long term display performance and the methods used for predicting in device lifetime from accelerated aging results. Test methods are described which give confidence in aging predictions.", "author_names": [ "James Thielen", "Dave Lamb", "Abby Lemon", "Josh Tibbits", "John F Van Derlofske", "Eric W Nelson" ], "corpus_id": 137907648, "doc_id": "137907648", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "27 2: Invited Paper: Correlation of Accelerated Aging to In Device Lifetime of Quantum Dot Enhancement Film", "venue": "", "year": 2016 }, { "abstract": "Semiconductor nanocrystals or quantum dots (QDs) should act as excellent Forster resonance energy transfer (FRET) acceptors due to their large absorption cross section, tunable emission, and high quantum yields. Engaging this type of FRET can be complicated due to direct excitation of the QD acceptor along with its longer excited state lifetime. Many cases of QDs acting as energy transfer acceptors are within time gated FRET from long lifetime lanthanides, which allow the QDs to decay before observing FRET. Efficient QD sensitization requires the lanthanide to be in close proximity to the QD. To overcome the lifetime mismatch issues and limited transfer range, we utilized a Cy3 dye to bridge the energy transfer from an extremely long lived terbium emitter to the QD. We demonstrated that short lifetime dyes can be used as energy transfer relays between extended lifetime components and in this way increased the distance of terbium QD FRET to ~14 nm.", "author_names": [ "Sebastian A Diaz", "Guillermo Lasarte Aragones", "Susan Buckhout-White", "Xue Qiu", "Eunkeu Oh", "Kimihiro Susumu", "Joseph S Melinger", "Alan L Huston", "Niko Hildebrandt", "Igor L Medintz" ], "corpus_id": 46875529, "doc_id": "46875529", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "Bridging Lanthanide to Quantum Dot Energy Transfer with a Short Lifetime Organic Dye.", "venue": "The journal of physical chemistry letters", "year": 2017 }, { "abstract": "To make quantum dot sensitized solar cells (QDSSCs) competitive, we investigated the effect of Ni(2+ ion incorporation into a CdS layer to create long lived charge carriers and reduce the electron hole recombination. The Ni(2+ doped CdS (simplified as CdNiS) QD layer was introduced to a TiO2 surface via the simple successive ionic layer adsorption and reaction (SILAR) method in order to introduce intermediate energy levels in the QDs. The effects of different Ni(2+ concentrations (5, 10, 15, and 20 mM) on the physical, chemical, and photovoltaic properties of the QDSSCs were investigated. The Ni(2+ dopant improves the light absorption of the device, accelerates the electron injection kinetics, and reduces the charge recombination, which results in improved charge transfer and collection. The 15% CdNiS cell exhibits the best photovoltaic performance with a power conversion efficiency (e) of 3.11% (JSC 8.91 mA cm( 2) VOC 0.643 V, FF 0.543) under one full sun illumination (AM 1.5 G) These results are among the best achieved for CdS based QDSSCs. Electrochemical impedance spectroscopy (EIS) and open circuit voltage decay (OCVD) measurements confirm that the Ni(2+ dopant can suppress charge recombination, prolong the electron lifetime, and improve the power conversion efficiency of the cells.", "author_names": [ "Chandu V V Muralee Gopi", "Mallineni Venkata-Haritha", "Hyunwoong Seo", "Saurabh Singh", "Soo-Kyoung Kim", "Masaharu Shiratani", "Hee-Jee Kim" ], "corpus_id": 206024978, "doc_id": "206024978", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Improving the performance of quantum dot sensitized solar cells through CdNiS quantum dots with reduced recombination and enhanced electron lifetime.", "venue": "Dalton transactions", "year": 2016 }, { "abstract": "The low efficiency and fast degradation of devices from ink jet printing process hinders the application of quantum dot light emitting diodes on next generation displays. Passivating the trap states caused by both anion and cation under coordinated sites on the quantum dot surface with proper ligands for ink jet printing processing reminds a problem. Here we show, by adapting the idea of dual ionic passivation of quantum dots, ink jet printed quantum dot light emitting diodes with an external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours were reported for the first time. The liquid phase exchange of ligands fulfills the requirements of ink jet printing processing for possible mass production. And the performance from ink jet printed quantum dot light emitting diodes truly opens the gate of quantum dot light emitting diode application for industry. Designing efficient and scalable quantum dot LEDs meeting industrial requirements remains a challenge. Here, the authors, by leveraging the liquid phase exchange of d MX 2 ligands, present printed quantum dot LEDs with external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours.", "author_names": [ "Chaoyu Xiang", "Longjia Wu", "Zizhe Lu", "Menglin Li", "Yanwei Wen", "Yixing Yang", "Wenyong Liu", "Tong-Yi Zhang", "Weiran Cao", "Sai-Wing Tsang", "Bin Shan", "Xiaolin Yan", "Lei Qian" ], "corpus_id": 214749901, "doc_id": "214749901", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "High efficiency and stability of ink jet printed quantum dot light emitting diodes", "venue": "Nature Communications", "year": 2020 } ]

[ { "abstract": "Stencil Printing Technology is currently a high throughput process for solder or adhesive materials deposition used in SMT and bumping process. With growth of heterogenous integration in the advanced semiconductor packaging is driving more stringent fine pitch application requirements. Disadvantages of Stencil Printing Technology for ultrafine pitch application, i.e. MicroLED Chip Attach, is restricted by stencil design (opening size) which resulted in frequent clogging of stencil and thus increase cost. Hence a \"stencil less\" technology for solder paste deposition via novel tape or film transfer process will be studied in this work. The paste transfer under development will require the use of low temperature profile to enable paste to deposit onto the substrate (receiver) and maintain structural integrity, probably in a semi state of paste form which can be subjected for Si die or microchip attach for reflow soldering to complete good solder interconnection during mass assemblies process.", "author_names": [ "Yam Lip Huei", "Lo Yee Ting", "Chong Kim Hui", "B Senthil Kumar", "Chan Li-san", "" ], "corpus_id": 231616077, "doc_id": "231616077", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solder Paste Transfer Via Pattern Tape Technology", "venue": "2020 IEEE 22nd Electronics Packaging Technology Conference (EPTC)", "year": 2020 }, { "abstract": "This paper presents a brief review on smart grids. Environmental destruction that is marked by high CO2 level or green house gas emissions due to excessive use of fossil fuels is a serious challenge that must be minimized immediately. One of the most prominent impact is the destruction of natural ecosystems such as forest fires due to very high temperature, rising sea level, flash flood, melting of iceberg in the north and south poles and uncertain natural climates. From the energy sec tor that contribute most to global warming is the power generation sector. Currently there are still many power plants that use fossil fuels such as petroleum and coal as the main source of turbine drive in generating electrical energy. Renewable energy is capable of generating electrical energy without generating and increasing greenhouse gases. Current renewable energy utilization trends continue to increase which contributes to the birth of the smart grid concept. Current electricity transmission and distribution networks can be categorized as conventional electricity networks because they have not been able to provide excellent service and present real time data. This network has not been able to provide reliability, safety and efficiency in supplying electrical energy even not yet have the flexibility to be integrated with the generation of renewable energy or microgrid. So the introduction of smart grid technology is a necessity to reduce the impact of global warming while encouraging efficiency, reliability and effective governance in the supply of electrical energy.", "author_names": [ "Alicia Tang Yee Chong", "Moamin A Mahmoud", "Fung-Cheng Lim", "Hairoladenan Kasim" ], "corpus_id": 226852402, "doc_id": "226852402", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A review of Smart Grid Technology, Components, and Implementation", "venue": "2020 8th International Conference on Information Technology and Multimedia (ICIMU)", "year": 2020 }, { "abstract": "3D NAND flash memory has become a state of the art technology of non volatile memory. Different from planar 2D NAND flash memory, polysilicon channel is adopted by 3D NAND flash memory. Because of grain boundaries, device suffers from significant performance variation. This work investigates the effect of grain boundary on MONOS structured NAND flash memory performance by TCAD simulation. The variability of electrical performance was demonstrated under random grain boundary structure. To further understand the grain boundary effect on device performance, grain size, grain boundary position and grain boundary angle was investigated. When grain size is smaller than gate length, it shows a larger threshold voltage variation. When grain size is big enough, the position of grain boundary matters. When grain boundary locates right below the middle of the gate, threshold voltage shifts the most. Moreover, comparing to vertical grain boundaries, the threshold voltage shifts up for grain boundaries in parallel to channel. This work includes a comprehensive study about the effect of grain boundary on 3D NAND flash memory performance. It could be used for the optimization of polysilicon process technology.", "author_names": [ "Sinan Yang", "Xuan Tian", "Jinghan Zhang", "Zhe Song", "Liang Li", "Ming Li", "Liming Gao" ], "corpus_id": 221912349, "doc_id": "221912349", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Investigation of Grain Boundaries Effect on 3D NAND Flash by TCAD Simulation", "venue": "2020 21st International Conference on Electronic Packaging Technology (ICEPT)", "year": 2020 }, { "abstract": "Scaling prospects and challenges of the embedded split gate SuperFlash(r)(ESF) memory technology to 28 nm and smaller process nodes are presented. We further propose a novel process integration scheme to build SuperFlash(r) memory with a 14nm process node. On going scaling and optimization of ESF memory technology continues to enable new applications such as machine learning in which an ESF memory array is used to implement vector matrix multiplications for neural networks. To demonstrate this use case, the capability and performance of 40 and 28 nm split gate SuperFlash(r) cells in low power sub threshold region is presented.", "author_names": [ "Nhan Do", "Steven Lemke", "Hieu Van Tran", "Vipin Tiwari", "Mark Reiten" ], "corpus_id": 221913618, "doc_id": "221913618", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Scaling of Split Gate Flash Memory for Embedded Controllers and Machine Learning Applications", "venue": "2020 International Symposium on VLSI Technology, Systems and Applications (VLSI TSA)", "year": 2020 }, { "abstract": "Hardware based neural networks are expected to be a new computing breakthrough beyond conventional von Neumann architecture because of their low power operations. In this work, we introduce operation scheme of neural networks using NAND flash memory cell as analogue and binary state synaptic devices. We report that NAND flash memory has excellent density and low error rate when compared to the results of RRAM.", "author_names": [ "Sungtae Lee", "Jongho Lee" ], "corpus_id": 229374003, "doc_id": "229374003", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Neuromorphic Technology Utilizing Nand Flash Memory Cells", "venue": "2020 China Semiconductor Technology International Conference (CSTIC)", "year": 2020 }, { "abstract": "NOR Flash has stopped scaling for many years. However, recently there are increasingly new demands of NOR Flash in various 5G and IoT applications or wearable devices that strongly require new technology advancement of NOR. In this work, we developed a new vertical 2T (V2T) NOR Flash architecture that provides not only scaling capability but also low power solutions. We leveraged the process of standard 3D NAND to develop a vertical 2T NOR that produces even smaller cell size than conventional planar 1T NOR. Advanced high K metal gate (HK/MG) integration is developed to provide high performance BE MANOS charge trapping device with excellent 1M endurance and retention reliability. The 2T NOR architecture provides low voltage read ~1V) that is compatible with advanced CMOS circuits without charge pumping to save power. We also suggest future technology extensions of the V2T NOR by adopting the ferroelectric memory devices (FeFET) and the 3DIC chiplets integration to broaden the applications fields of NOR technology in embedded Flash and computing in memory (CIM)", "author_names": [ "Hang-Ting Lue", "Tzu-Hsuan Hsu", "Teng-hao Yeh", "Wei-Chen Chen", "Chieh Roger Lo", "Chiatze Huang", "Guan-Ru Lee", "Chia-Jung Chiu", "Keh-Chung Wang", "Chih-Yuan Lu" ], "corpus_id": 227277131, "doc_id": "227277131", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "A Vertical 2T NOR (V2T) Architecture to Enable Scaling and Low Power Solutions for NOR Flash Technology", "venue": "2020 IEEE Symposium on VLSI Technology", "year": 2020 }, { "abstract": "The flash industry has continuously produced game changing innovations in density, latency, and form factors resulting in large cost performance benefits. To address the wide spectrum of storage demands coming from phone/IoT devices, mobile compute, up to data centers, new flash architectures are essential to handle these next generation applications. Future technology must include not only new architectures and more layers in flash chip designs, but also a roadmap for QLC flash and beyond, new memories, new classes of SSDs, and new software technologies. They must all come together to enable and accelerate the next wave of applications including the real time analytics, AI (Artificial Intelligence)/ML (Machine Learning) high performance computing, IoT, and virtual and augmented reality.", "author_names": [ "Shigeo Ohshima" ], "corpus_id": 227278675, "doc_id": "227278675", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Empowering Next Generation Applications through FLASH Innovation", "venue": "2020 IEEE Symposium on VLSI Technology", "year": 2020 }, { "abstract": "2.5D multichip module packaging technology for higher end devices like CPU, GPU, 3D NAND flash memory and High Bandwidth Memory (HBM) require two major molding process solutions: higher thermal performance and narrow gap underfill. Apic Yamada Corporation of Japan, as a semiconductor back end total solution provider, proposes technology solutions utilizing advanced molding technologies which enable chip surface exposure and Mold Underfill (MUF) for narrow gaps.With conventional molding technology, the mold resin on the top surface of the chip is removed by a grinding process after the molding process in order to improve thermal resistance thja. However, the latest transfer molding technology enables chip exposure without a grinding process. This technology can be applied to a wide range of higher end advanced packaging technologies such as 2.5D, 3D and others. The conventional chip exposure molding method using elastic release film, which covers the inside of the mold cavity, can absorb chip height variations. In addition, the most advanced available chip exposure molding system applies reduced pressure and lower mechanical stress to the chip. This low stress molding process comprises several new system technologies including chip height measurement using a laser displacement sensor, which is self calculating to provide the optimum cavity level for chip exposure, by adjusting the cavity block position each cycle.In this study, solutions for chip height variation such as 20um and height control range within 300um with low stress will be presented. In addition, we propose newly developed vacuum molding technology and movable air vent technology for MUF with void less filling of narrow gap spaces under the chips. Proper mold resin material selection to achieve high filling, optimal heat shrinkage and minimized warpage is one of the key factors. The new technology also provides economic advantages due to reduced process steps and shorter process time compared to the Capillary Underfill (CUF) process which is widely used in the marketplace.In order to achieve a reliable MUF process targeting less than 8um gaps and less than 15um pitch, Apic Yamada's molding system has tighter control for discharging internal air and generated gas to the outside. This is accomplished while also controlling vacuum conditions, using chip volume measurement by laser displacement sensor and 3D image measurement which calculates the resin flow front on each shot.", "author_names": [ "Takashi Saito", "Tokuyuki Kitajima", "Makoto Kawaguchi", "Shinya Tajima", "Masashi Okamoto" ], "corpus_id": 225849645, "doc_id": "225849645", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "New Molding Technology Enabling Advanced Packaging Technology", "venue": "2020 IEEE 70th Electronic Components and Technology Conference (ECTC)", "year": 2020 }, { "abstract": "In this paper, mobility model for poly Si based macaroni structure in 3 D NAND Flash memory is presented. String current was calibrated with technology computer aided design (TCAD) simulation at room temperature (25degC) with U shaped trap distribution. Then, unit word line (WL) I V curve was extracted, and effective mobility was extracted from these data using analytical equation. Mobility model is based on Meyer Neldel Rule (MNR) We extracted grain boundary barrier height \\varphi_{\\mathrm{b} and fitted with our model. Finally, we fitted effective mobility \\mu_{\\mathrm{eff} with our model and fitted string current with SPICE simulation.", "author_names": [ "Hyungjun Jo", "Juhyun Kim", "Minsoo Kim", "Hyungcheol Shin" ], "corpus_id": 219858012, "doc_id": "219858012", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Extraction of Mobility in 3 D NAND Flash Memory with Poly Si Based Macaroni Structure", "venue": "2020 4th IEEE Electron Devices Technology Manufacturing Conference (EDTM)", "year": 2020 }, { "abstract": "We investigated process variation effect of 3D NAND flash memory cell, especially about geometric variation using a machine learning (ML) model. Geometric variability sources impact on variation of device's electrical parameters such as threshold voltage \\mathbf{V}_{\\mathbf{t} subthreshold swing (SS) transconductance \\mathbf{g}_{\\mathbf{m} and on current \\mathbf{I}_{\\mathbf{on} All these data were analyzed with 3D stochastic Technology Computer Aided Design (TCAD) simulation and trained through ML model, which is composed of artificial neural network (ANN) The model has multi input and multi output (MIMO) structure and deep hidden layers to train and predict complex data of process variation. In order to make ML model more accurate, simulation for constructing training data set was carried out with a large number of random unit cells, which are cut from various strings. The completed ML model was tested with random test data set which had not been used for training to prove its accuracy. Through the test process, ML model showed the error of up to 5% and proved the accuracy of prediction.", "author_names": [ "Jang Kyu Lee", "Kyul Ko", "Hyungcheol Shin" ], "corpus_id": 219854695, "doc_id": "219854695", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Analysis on Process Variation Effect of 3D NAND Flash Memory Cell through Machine Learning Model", "venue": "2020 4th IEEE Electron Devices Technology Manufacturing Conference (EDTM)", "year": 2020 } ]

[ { "abstract": "Laser spectroscopy outperforms electrochemical and semiconductor gas sensors in selectivity and environmental survivability. However, the performance of the state of the art laser sensors is still insufficient for many high precision applications. Here, we report mode phase difference photothermal spectroscopy with a dual mode anti resonant hollow core optical fiber and demonstrate all fiber gas (acetylene) detection down to ppt (parts per trillion) and <1% instability over a period of 3 hours. An anti resonant hollow core fiber could be designed to transmit light signals over a broad wavelength range from visible to infrared, covering molecular absorption lines of many important gases. This would enable multi component gas detection with a single sensing element and pave the way for ultra precision gas sensing for medical, environmental and industrial applications. Typically, the performance of the state of the art laser sensors is insufficient for many high precision applications. Here, the authors report mode phase difference photothermal spectroscopy with a dual mode anti resonant hollow core optical fiber and demonstrate acetylene detection with ultra high sensitivity.", "author_names": [ "Pengcheng Zhao", "Yan Zhao", "Haihong Bao", "Hoi Lut Ho", "Wei Jin", "Shangchun Fan", "Shoufei Gao", "Yingying Wang", "Pu Wang" ], "corpus_id": 211081263, "doc_id": "211081263", "n_citations": 25, "n_key_citations": 0, "score": 1, "title": "Mode phase difference photothermal spectroscopy for gas detection with an anti resonant hollow core optical fiber", "venue": "Nature Communications", "year": 2020 }, { "abstract": "We report the fabrication and characterization of the first double clad tubular anti resonant hollow core fiber. It allows to deliver ultrashort pulses without temporal nor spectral distortions in the 700 1000 nm wavelength range and to efficiently collect scattered light in a high numerical aperture double clad. The output fiber mode is shaped with a silica microsphere generating a photonic nanojet, making it well suitable for nonlinear microendoscopy application. Additionally, we provide an open access software allowing to find optimal drawing parameters for the fabrication of tubular hollow core fibers.", "author_names": [ "Alexandre Kudlinski", "Andy Cassez", "Olivier Vanvincq", "D Septier", "A Pastre", "Remi Habert", "Karen Baudelle", "Marc Douay", "Vasyl Mytskaniuk", "Victor Tsvirkun", "Herve Rigneault", "Geraud Bouwmans" ], "corpus_id": 218635594, "doc_id": "218635594", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Double clad tubular anti resonant hollow core fiber for nonlinear microendoscopy.", "venue": "Optics express", "year": 2020 }, { "abstract": "This dataset contains data supporting the results presented in the paper \"Birefringent Anti resonant Hollow core Fiber\" and the supplementary material. It includes the data used to plot each figure (in .xlsx format) together with simulated data obtained using COMSOL. Hollow core fibres have demonstrated record performance in applications such as high power pulse delivery, quantum computing, and sensing. However, their routine use is yet to become reality. A major obstacle is the ability to maintain the polarisation state of light over a broad range of wavelengths, while also ensuring single mode guidance and attenuation that is low enough for practical applications that require only a few meters of fibre length <1 dB/m) Here we simulated, fabricated and characterized a single mode birefringent anti resonant hollow core fibre. The birefringence was achieved by introducing capillary tubes of different thicknesses, thereby creating reduced symmetry in the structure. The measured group birefringence is in good agreement with the calculated group birefringence from simulations across the fibre guidance band within the telecommunications C band. At 1550 nm, we measured a group birefringence of 4.4E 5, which corresponds to a phase birefringence of 2.5E 5. The measured loss of the fibre was 0.46 dB/m at 1550 nm. The measured polarisation extinction ratio of the fibre at 1550 nm was 23.1 dB (25.7 dB) along the x (y polarisation axis, relating to an h parameter of 9.8E 4 (5.3E 4)", "author_names": [ "Stephanos Yerolatsitis", "Riley Shurvinton", "Peng Song", "Ya-ping Zhang", "Robert J A Francis-Jones", "Kristina R Rusimova" ], "corpus_id": 214343891, "doc_id": "214343891", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Dataset for \"Birefringent Anti resonant Hollow core Fiber\"", "venue": "", "year": 2020 }, { "abstract": "Optimizing period of tooth spacing could improve the sensitivity in a microbend sensor based on multimode fiber. A new design of anti resonant hollow core fiber has experimentally further improved the microbending sensitivity. (c) 2020 The Author(s)", "author_names": [ "Donglai An", "Xu Chen", "Ying-ying Wang", "Shoufei Gao", "Xia Yu" ], "corpus_id": 232152103, "doc_id": "232152103", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "High sensitivity microbend sensor based on anti resonant hollow core fiber", "venue": "2020 Asia Communications and Photonics Conference (ACP) and International Conference on Information Photonics and Optical Communications (IPOC)", "year": 2020 }, { "abstract": "We demonstrate frequency down conversions of femtosecond pulses through dispersive wave generation and degenerate four wave mixing in a gas filled anti resonant hollow core fiber. These are achieved by exploiting the rapid variation of the dispersion in the fiber's transmission band edge. In this approach, the wavelength of the down shifted radiation is governed solely by the thickness of the dielectric wall at the core cladding interface, while other system parameters are accountable only for inducing sufficient nonlinear phase shifts. With the right choice of cladding wall thickness, the concept can be applied directly for generating high power mid infrared femtosecond pulses.", "author_names": [ "Trivikramarao Gavara", "Md Imran Hasan", "Muhammad Rosdi Abu Hassan", "Ang Deng", "Wonkeun Chang" ], "corpus_id": 229281402, "doc_id": "229281402", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Band edge mediated frequency down conversion in a gas filled anti resonant hollow core fiber.", "venue": "Optics letters", "year": 2020 }, { "abstract": "We report the generation of phase matched long wavelength radiation at a transmission band edge of an anti resonant hollow core fiber filled with gas. This is achieved with the aid of the resonance induced dispersion change at the band edge.", "author_names": [ "Trivikramarao Gavara", "Muhammad Rosdi Abu Hassan", "Ang Deng", "Wonkeun Chang" ], "corpus_id": 229530285, "doc_id": "229530285", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Generation of Long Wavelength Radiation in Gas Filled Anti Resonant Hollow Core Fiber", "venue": "", "year": 2020 }, { "abstract": "Hollow core fibers have demonstrated record performance in applications such as high power pulse delivery, quantum computing, and sensing. However, their routine use is yet to become reality. A major obstacle is the ability to maintain the polarization state of light over a broad range of wavelengths, while also ensuring single mode guidance and attenuation that is low enough for practical applications that require only a few meters of fiber length <1 dB/m) Here we simulated, fabricated, and characterized a single mode birefringent anti resonant hollow core fiber. The birefringence was achieved by introducing capillary tubes of different thicknesses, thereby creating reduced symmetry in the structure. The measured group birefringence is in good agreement with the calculated group birefringence from simulations across the fiber guidance band within the telecommunications C band. At 1550 nm, we measured a group birefringence of 4.4 x 10 5, which corresponds to a phase birefringence of 2.5 x 10 5. The measured loss of the fiber was 0.46 dB/m at 1550 nm. The measured polarization extinction ratio of the fiber at 1550 nm was 23.1 dB (25.7 dB) along the x (y polarization axis, relating to an h parameter of 9.8 x 10 4 (5.3 x 10 4)", "author_names": [ "Stephanos Yerolatsitis", "Riley Shurvinton", "Peng Song", "Ya-ping Zhang", "Robert J A Francis-Jones", "Kristina R Rusimova" ], "corpus_id": 221006680, "doc_id": "221006680", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Birefringent Anti Resonant Hollow Core Fiber", "venue": "Journal of Lightwave Technology", "year": 2020 }, { "abstract": "Transmission of dark hollow beams is crucial for blue detuned guiding of cold atoms, and it is fundamental for cold atom interferometers. We proposed four anti resonant hollow core fiber structures for transporting dark hollow beam, and then comparing their confinement loss. We chose the fiber structure with simpler structure and lower confinement loss to get fiber samples. Besides we built a fiber coupled system to test the fiber properties. The experimental results show that the fiber can better maintain the light intensity of the hollow beam, which are crucial for guiding atoms.", "author_names": [ "Xiaobin Xu", "Di Zhao", "Fuyu Gao", "Yitong Song", "He Xu" ], "corpus_id": 218778993, "doc_id": "218778993", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Transmission of a dark hollow beam by anti resonant hollow core fiber", "venue": "", "year": 2020 }, { "abstract": "In this paper we report a mid infrared sensor based on an anti resonant hollow core fiber. A quantum cascade laser operating around 4.53 um is used to target one of the strongest transition of nitrous oxide near 2203.7 cm 1. The system provides 1 second minimum detection limit at single parts per billion level using 3.2 m long fiber with the response time of less than 30 seconds. Presented sensing approach shows a good perspective for compact and sensitive mid infrared fiber based spectrometers.", "author_names": [ "Michal Nikodem", "Grzegorz Gomolka", "Mariusz Klimczak", "Dariusz Pysz", "Ryszard Buczynski" ], "corpus_id": 209463110, "doc_id": "209463110", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Demonstration of mid infrared gas sensing using an anti resonant hollow core fiber and a quantum cascade laser.", "venue": "Optics express", "year": 2019 }, { "abstract": "In this paper, we present a laser based sensing inside anti resonant hollow core fiber. A distributed feedback laser diode operating near 2004 nm and a 1.35 m long silica based fiber are used to demonstrate carbon dioxide detection with sensitivity down to ~5 ppmv. Gas exchange time as low as 5 seconds is obtained. This performance was achieved in a very simple optical configuration, without any mirrors or lenses in the setup.", "author_names": [ "Michal Nikodem", "Grzegorz Gomolka", "Mariusz Klimczak", "Dariusz Pysz", "Ryszard Buczynski" ], "corpus_id": 165121769, "doc_id": "165121769", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Laser absorption spectroscopy at 2 um inside revolver type anti resonant hollow core fiber.", "venue": "Optics express", "year": 2019 } ]

[ { "abstract": "Stacking different two dimensional crystals into van der Waals heterostructures provides an exciting approach to designing quantum materials that can harness and extend the already fascinating properties of the constituents. Heterobilayers of transition metal dichalcogenides are particularly attractive for low dimensional semiconductor optics because they host interlayer excitons with electrons and holes localized in different layers which inherit valley contrasting physics from the monolayers and thereby possess various novel and appealing properties compared to other solid state nanostructures. This Review presents the contemporary experimental and theoretical understanding of these interlayer excitons. We discuss their unique optical properties arising from the underlying valley physics, the strong many body interactions and electrical control resulting from the electric dipole moment, and the unique effects of a moire superlattice on the interlayer exciton potential landscape and optical properties.This Review discusses the contemporary experimental and theoretical understanding of interlayer excitons in heterobilayers of transition metal dichalcogenides.", "author_names": [ "Pasqual Rivera", "Hongyi Yu", "Kyle L Seyler", "N P Wilson", "Wang Yao", "Xiaodong Xu" ], "corpus_id": 51977961, "doc_id": "51977961", "n_citations": 188, "n_key_citations": 2, "score": 1, "title": "Interlayer valley excitons in heterobilayers of transition metal dichalcogenides", "venue": "Nature Nanotechnology", "year": 2018 }, { "abstract": "Van der Waals (vdW) heterobilayers formed by two dimensional (2D) transition metal dichalcogenides (TMDCs) created a promising platform for various electronic and optical properties. ab initio band results indicate that the band offset of type II band alignment in TMDCs vdW heterobilayer could be tuned by introducing Janus WSSe monolayer, instead of an external electric field. On the basis of symmetry analysis, the allowed interlayer hopping channels of TMDCs vdW heterobilayer were determined, and a four level kp model was developed to obtain the interlayer hopping. Results indicate that the interlayer coupling strength could be tuned by interlayer electric polarization featured by various band offsets. Moreover, the difference in the formation mechanism of interlayer valley excitons in different TMDCs vdW heterobilayers with various interlayer hopping strength was also clarified.", "author_names": [ "Fengping Li", "Wei Wei", "Baibiao Huang", "Ying Dai" ], "corpus_id": 222140058, "doc_id": "222140058", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Interlayer coupling effect in van der Waals heterostructures of transition metal dichalcogenides", "venue": "Frontiers of Physics", "year": 2020 }, { "abstract": "We present a theory of optical absorption by interlayer excitons in a heterobilayer formed from transition metal dichalcogenides. The theory accounts for the presence of small relative rotations that produce a momentum shift between electron and hole bands located in different layers, and a moir\\'e pattern in real space. Because of the momentum shift, the optically active interlayer excitons are located at the moir\\'e Brillouin zone's corners, instead of at its center, and would have elliptical optical selection rules if the individual layers were translationally invariant. We show that the exciton moir\\'e potential energy restores circular optical selection rules by coupling excitons with different center of mass momenta. A variety of interlayer excitons with both senses of circular optical activity, and energies that are tunable by twist angle, are present at each valley. The lowest energy exciton states are generally localized near the exciton potential energy minima. We discuss the possibility of using the moir\\'e pattern to achieve scalable two dimensional arrays of nearly identical quantum dots.", "author_names": [ "Fengcheng Wu", "Timothy Lovorn", "Allan H MacDonald" ], "corpus_id": 53624454, "doc_id": "53624454", "n_citations": 109, "n_key_citations": 3, "score": 0, "title": "Theory of optical absorption by interlayer excitons in transition metal dichalcogenide heterobilayers", "venue": "", "year": 2017 }, { "abstract": "We show that, because of the inevitable twist and lattice mismatch in heterobilayers of transition metal dichalcogenides, interlayer excitons have sixfold degenerate light cones anomalously located at finite velocities on the parabolic energy dispersion. The photon emissions at each light cone are elliptically polarized, with the major axis locked to the direction of exciton velocity, and helicity specified by the valley indices of the electron and the hole. These finite velocity light cones allow unprecedented possibilities for optically injecting valley polarization and valley current, and the observation of both direct and inverse valley Hall effects, by exciting interlayer excitons. Our findings suggest potential excitonic circuits with valley functionalities, and unique opportunities to study exciton dynamics and condensation phenomena in semiconducting 2D heterostructures.", "author_names": [ "Hongyi Yu", "Yong Wang", "Qingjun Tong", "Xiaodong Xu", "Wang Yao" ], "corpus_id": 22312840, "doc_id": "22312840", "n_citations": 130, "n_key_citations": 1, "score": 0, "title": "Anomalous Light Cones and Valley Optical Selection Rules of Interlayer Excitons in Twisted Heterobilayers.", "venue": "Physical review letters", "year": 2015 }, { "abstract": "Van der Waals heterostructures offer attractive opportunities to design quantum materials. For instance, transition metal dichalcogenides (TMDs) possess three quantum degrees of freedom: spin, valley index and layer index. Furthermore, twisted TMD heterobilayers can form moire patterns that modulate the electronic band structure according to the atomic registry, leading to spatial confinement of interlayer excitons (IXs) Here we report the observation of spin layer locking of IXs trapped in moire potentials formed in a heterostructure of bilayer 2H MoSe 2 and monolayer WSe 2 The phenomenon of locked electron spin and layer index leads to two quantum confined IX species with distinct spin layer valley configurations. Furthermore, we observe that the atomic registries of the moire trapping sites in the three layers are intrinsically locked together due to the 2H type stacking characteristic of bilayer TMDs. These results identify the layer index as a useful degree of freedom to engineer tunable few level quantum systems in two dimensional heterostructures. The optical properties of two species of localized interlayer excitons in a van der Waals heterostructure are shown to depend on their spin valley layer configuration, enabling the identification of the moire atomic registry and offering insights for engineering quantum states in two dimensional materials.", "author_names": [ "Mauro Brotons-Gisbert", "Hyeonjun Baek", "Alejandro Molina-Sanchez", "Aidan Campbell", "Eleanor Scerri", "Daniel White", "Kenji Watanabe", "Takashi Taniguchi", "Cristian Bonato", "Brian D Gerardot" ], "corpus_id": 199543870, "doc_id": "199543870", "n_citations": 37, "n_key_citations": 1, "score": 0, "title": "Spin layer locking of interlayer excitons trapped in moire potentials", "venue": "Nature Materials", "year": 2020 }, { "abstract": "Layered two dimensional materials exhibit rich transport and optical phenomena in twisted or lattice incommensurate heterostructures with spatial variations of interlayer hybridization arising from moire interference effects. Here, we report experimental and theoretical studies of excitons in twisted heterobilayers and heterotrilayers of transition metal dichalcogenides. Using MoSe2 WSe2 stacks as representative realizations of twisted van der Waals bilayer and trilayer heterostructures, we observe contrasting optical signatures and interpret them in the theoretical framework of interlayer moire excitons in different spin and valley configurations. We conclude that the photoluminescence of MoSe2 WSe2 heterobilayer is consistent with joint contributions from radiatively decaying valley direct interlayer excitons and phonon assisted emission from momentum indirect reservoirs that reside in spatially distinct regions of moire supercells, whereas the heterotrilayer emission is entirely due to momentum dark interlayer excitons of hybrid layer valleys. Our results highlight the profound role of interlayer hybridization for transition metal dichalcogenide heterostacks and other realizations of multi layered semiconductor van der Waals heterostructures.", "author_names": [ "Michael Forg", "Anvar S Baimuratov", "Stanislav Yu Kruchinin", "Ilia A Vovk", "Johannes Scherzer", "J Forste", "Victor Funk", "Kenji Watanabe", "Takashi Taniguchi", "Alexander Hogele" ], "corpus_id": 219708889, "doc_id": "219708889", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Moire excitons in MoSe2 WSe2 heterobilayers and heterotrilayers", "venue": "Nature communications", "year": 2021 }, { "abstract": "Van der Waals heterobilayers of transition metal dichalcogenides with spin valley coupling of carriers in different layers have emerged as a new platform for exploring spin/valleytronic applications. The interlayer coupling was predicted to exhibit subtle changes with the interlayer atomic registry. Manually stacked heterobilayers, however, are incommensurate with the inevitable interlayer twist and/or lattice mismatch, where the properties associated with atomic registry are difficult to access by optical means. Here, we unveil the distinct polarization properties of valley specific interlayer excitons using epitaxially grown, commensurate WSe2/MoSe2 heterobilayers with well defined (AA and AB) atomic registry. We observe circularly polarized photoluminescence from interlayer excitons, but with a helicity opposite to the optical excitation. The negative circular polarization arises from the quantum interference imposed by interlayer atomic registry, giving rise to distinct polarization selection rules for interlayer excitons. Using selective excitation schemes, we demonstrate the optical addressability for interlayer excitons with different valley configurations and polarization helicities.The interlayer coupling in van der Waals heterostructures is sensitive to the interlayer atomic registry. Here, the authors investigate the polarisation properties of epitaxially grown, commensurate WSe2/MoSe2 heterobilayers with well defined atomic registry, and observe negative, circularly polarized photoluminescence from interlayer excitons.", "author_names": [ "Wei-Ting Hsu", "Li-Syuan Lu", "Po-Hsun Wu", "Ming-Hao Lee", "Peng-Jen Chen", "Pei-Ying Wu", "Yi-Chia Chou", "Horng-Tay Jeng", "Lain-Jong Li", "M W Chu", "Wen-Hao Chang" ], "corpus_id": 4749237, "doc_id": "4749237", "n_citations": 59, "n_key_citations": 0, "score": 0, "title": "Negative circular polarization emissions from WSe2/MoSe2 commensurate heterobilayers", "venue": "Nature Communications", "year": 2018 }, { "abstract": "van der Waals heterostructures formed by stacking two dimensional atomic crystals are a unique platform for exploring new phenomena and functionalities. Interlayer excitons, bound states of spatially separated electron hole pairs in van der Waals heterostructures, have demonstrated potential for rich valley physics and optoelectronics applications and been proposed to facilitate high temperature superfluidity. Here, we demonstrate highly tunable interlayer excitons by an out of plane electric field in homobilayers of transition metal dichalcogenides. Continuous tuning of the exciton dipole from negative to positive orientation has been achieved, which is not possible in heterobilayers due to the presence of large built in interfacial electric fields. A large linear field induced redshift up to ~100 meV has been observed in the exciton resonance energy. The Stark effect is accompanied by an enhancement of the exciton recombination lifetime by more than two orders of magnitude to >20 ns. The long recombination lifetime has allowed the creation of an interlayer exciton gas with density as large as 1.2 x 1011 cm 2 by moderate continuous wave optical pumping. Our results have paved the way for the realization of degenerate exciton gases in atomically thin semiconductors.", "author_names": [ "Zefang Wang", "Yi-Hsin Chiu", "Kevin Honz", "Kin Fai Mak", "Jie Shan" ], "corpus_id": 206744137, "doc_id": "206744137", "n_citations": 68, "n_key_citations": 3, "score": 0, "title": "Electrical Tuning of Interlayer Exciton Gases in WSe2 Bilayers.", "venue": "Nano letters", "year": 2018 }, { "abstract": "Transition metal dichalcogenides (TMDs) constitute a versatile platform for atomically thin optoelectronics devices and spin valley memory applications. In monolayer TMDs the optical absorption is strong, but the transition energy cannot be tuned as the neutral exciton has essentially no out of plane static electric dipole 1 2 In contrast, interlayer exciton transitions in heterobilayers are widely tunable in applied electric fields, but their coupling to light is substantially reduced. In this work, we show tuning over 120 meV of interlayer excitons with a high oscillator strength in bilayer MoS 2 due to the quantum confined Stark effect 3 We optically probed the interaction between intra and interlayer excitons as they were energetically tuned into resonance. Interlayer excitons interact strongly with intralayer B excitons, as demonstrated by a clear avoided crossing, whereas the interaction with intralayer A excitons is substantially weaker. Our observations are supported by density functional theory (DFT) calculations, which include excitonic effects. In MoS 2 trilayers, our experiments uncovered two types of interlayer excitons with and without in built electric dipoles. Highly tunable excitonic transitions with large in built dipoles and oscillator strengths will result in strong exciton exciton interactions and therefore hold great promise for non linear optics with polaritons. Interlayer excitons in bilayer MoS 2 exhibit both a high oscillator strength and highly tunable energies in an applied electric field.", "author_names": [ "Nadine Leisgang", "Shivangi Shree", "Ioannis Paradisanos", "Lukas Sponfeldner", "Cedric Robert", "D Lagarde", "Andrea Balocchi", "Kenji Watanabe", "Takashi Taniguchi", "Xavier Marie", "Richard John Warburton", "Iann C Gerber", "Bernhard Urbaszek" ], "corpus_id": 211066293, "doc_id": "211066293", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Giant Stark splitting of an exciton in bilayer MoS2", "venue": "Nature Nanotechnology", "year": 2020 }, { "abstract": "Geometrical moire patterns, generic for almost aligned bilayers of two dimensional (2D) crystals with similar lattice structure but slightly different lattice constants, lead to zone folding and miniband formation for electronic states. Here, we show that moire superlattice (mSL) effects in MoSe$}_2$/WS$}_2$ and MoTe$}_2$/MoSe$}_2$ heterobilayers that feature alignment of the band edges are enhanced by resonant interlayer hybridization. Such hybridization determines the optical activity of interlayer excitons in transition metal dichalcogenide (TMD) heterostructures, as well as energy shifts in the exciton spectrum. We show that the resonantly hybridized exciton (hX) energy should display a sharp modulation as a function of the interlayer twist angle, accompanied by additional spectral features caused by umklapp electron photon interactions. We analyze the appearance of resonantly enhanced mSL features in absorption and emission of light by the interlayer exciton hybridization with both intralayer A and B excitons in MoSe$}_2$/WS$}_2$ MoTe$}_2$/MoSe$}_2$ MoSe$}_2$/MoS$}_2$ and WSe$}_2$/MoS$}_2$ and anticipate similar features in twisted homobilayers of TMDs.", "author_names": [ "David A Ruiz-Tijerina", "Vladimir I Fal'ko" ], "corpus_id": 85517534, "doc_id": "85517534", "n_citations": 50, "n_key_citations": 2, "score": 0, "title": "Interlayer hybridization and moire superlattice minibands for electrons and excitons in heterobilayers of transition metal dichalcogenides", "venue": "Physical Review B", "year": 2019 } ]

[ { "abstract": "Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon (Si) germanium (Ge) and SiGe alloys are all indirect bandgap semiconductors that cannot emit light efficiently. The goal 1 of achieving efficient light emission from group IV materials in silicon technology has been elusive for decades 2 6 Here we demonstrate efficient light emission from direct bandgap hexagonal Ge and SiGe alloys. We measure a sub nanosecond, temperature insensitive radiative recombination lifetime and observe an emission yield similar to that of direct bandgap group III V semiconductors. Moreover, we demonstrate that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously tuned over a broad range, while preserving the direct bandgap. Our experimental findings are in excellent quantitative agreement with ab initio theory. Hexagonal SiGe embodies an ideal material system in which to combine electronic and optoelectronic functionalities on a single chip, opening the way towards integrated device concepts and information processing technologies. A hexagonal (rather than cubic) alloy of silicon and germanium that has a direct (rather than indirect) bandgap emits light efficiently across a range of wavelengths, enabling electronic and optoelectronic functionalities to be combined on a single chip.", "author_names": [ "Elham M T Fadaly", "Alain Dijkstra", "Jens Rene Suckert", "Dorian Ziss", "Marvin A J van Tilburg", "Chenyang Mao", "Yizhen Ren", "Victor T van Lange", "Ksenia Korzun", "Sebastian Kolling", "Marcel A Verheijen", "David Busse", "Claudia Rodl", "Jurgen Furthmuller", "Friedhelm Bechstedt", "J Stangl", "Jonathan J Finley", "Silvana Botti", "Jos E M Haverkort", "Erik P A M Bakkers" ], "corpus_id": 207870211, "doc_id": "207870211", "n_citations": 79, "n_key_citations": 1, "score": 1, "title": "Direct bandgap emission from hexagonal Ge and SiGe alloys", "venue": "Nature", "year": 2020 }, { "abstract": "Novel group IV nanostructures were fabricated and the optical properties of such nanostructures were investigated for monolithic integration of optically active materials with silicon. The SnxGe1 x alloy system was studied due to the previous demonstration of an indirect to direct energy bandgap transition for strain relieved SnxGe1 x films on Si(001) In addition, quantum confined structures of Sn were fabricated and the optical properties were investigated. Due to the small electron effective mass of a Sn, quantum confinement effects are expected at relatively large radii. Coherently strained, epitaxial SnxGe1 x films on Ge(001) substrates were synthesized with film thickness exceeding 100 nm for the first time. The demonstration of dislocation free SnxGe1 x films is a step toward the fabrication of silicon based integrated infrared optoelectronic devices. The optical properties of coherently strained SnxGe1 x/Ge(001) alloys were investigated both theoretically and experimentally. Deformation potential theory calculations were performed to predict the effect of coherency strain on the extrema points of the conduction band and the valence band. The energy bandgap of SnxGe1 x/Ge(001) alloys was measured via Fourier transform infrared spectroscopy. Coherency strain did not change the SnxGe1 x energy bandgap when the strain axis was along [001] but deformation potential theory predicted the absence of an indirect to direct energy bandgap transition when the strain axis was along [111] In addition to being the only group IV alloy exhibiting a direct energy bandgap, when grown beyond a critical thickness, SnxGe1 x/Ge(001) exhibits an interesting phenomenon during MBE growth. Sn segregates via surface diffusion to the crest of a surface undulation during growth and forms ordered Sn enriched SnxGe1 x rods oriented along [001] The SnxGe1 x alloy system was used as a model system to gain insight to the physical mechanisms governing self assembly and ordering during molecular beam epitaxy. Sn nanowires were fabricated in anodic alumina templates with lengths exceeding 1 mm and diameters on the order of 40 nm. Anodic alumina templates can be fabricated non lithographically with ordered domains of hexagonally packed pores greater than 1 mm and pore densities on the order of 1011 cm 2. The achievement of single crystal Sn nanowires fabricated using pressure injection in porous alumina templates was demonstrated. The fabrication of a Sn quantum dots embedded in Ge was achieved by annealing 1 mm thick SnxGe1 x films at 750degC. The measured diameter of the quantum dots was 32 nm and a 10% size variation was observed. Quantum size effects were observed in a Sn quantum dots. Optical transmittance measurements yield a value of 0.45 eV for the direct energy bandgap as a result of quantum confinement. A high degree of tunability of the bandgap energy with the quantum dot radius is expected for a Sn. Thus quantum confined structures of a Sn are promising for optoelectronic device applications.", "author_names": [ "Regina Ragan" ], "corpus_id": 135541931, "doc_id": "135541931", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Direct Energy Bandgap Group IV Alloys and Nanostructures", "venue": "", "year": 2002 }, { "abstract": "In this paper we investigate the influence of n type doping in Ge light emitting diodes on Si substrates on the room temperature emission spectrum. The layer structures are grown with a special low temperature molecular beam epitaxy process resulting in a slight tensile strain of 0.13% The Ge LED's show a dominant direct bandgap emission with shrinking bandgap at the G point in dependence of n type doping level. The emission shift (38 meV at 1020cm 3) is mainly assigned to bandgap narrowing at high doping. The electroluminescence intensity increases with doping concentrations up to 3x1019cm 3 and decreases sharply at higher doping levels. The integrated direct gap emission intensity increases superlinear with electrical current density. Power exponents vary from about 2 at low doping densities up to 3.6 at 1020cm 3 doping density.", "author_names": [ "Michael Oehme", "Martin Gollhofer", "Daniel Widmann", "Marc Schmid", "Mathias Kaschel", "Erich Kasper", "Jorg Schulze" ], "corpus_id": 2712907, "doc_id": "2712907", "n_citations": 65, "n_key_citations": 2, "score": 0, "title": "Direct bandgap narrowing in Ge LED's on Si substrates.", "venue": "Optics express", "year": 2013 }, { "abstract": "Recent advances in the synthetic growth of nanowires have given access to crystal phases that in bulk are only observed under extreme pressure conditions. Here, we use first principles methods based on density functional theory and many body perturbation theory to show that a suitable mixing of hexagonal Si and hexagonal Ge yields a direct bandgap with an optically permitted transition. Comparison of the calculated radiative lifetimes with typical values of nonradiative recombination mechanisms indicates that optical emission will be the dominant recombination mechanism. These findings pave the way to the development of silicon based optoelectronic devices, thus far hindered by the poor light emission efficiency of cubic Si.", "author_names": [ "Xavier Cartoixa", "Maurizia Palummo", "Hakon Ikaros T Hauge", "Erik P A M Bakkers", "Riccardo Rurali" ], "corpus_id": 206741070, "doc_id": "206741070", "n_citations": 39, "n_key_citations": 1, "score": 0, "title": "Optical Emission in Hexagonal SiGe Nanowires.", "venue": "Nano letters", "year": 2017 }, { "abstract": "We present a comprehensive, up to date compilation of band parameters for the technologically important III V zinc blende and wurtzite compound semiconductors: GaAs, GaSb, GaP, GaN, AlAs, AlSb, AlP, AlN, InAs, InSb, InP, and InN, along with their ternary and quaternary alloys. Based on a review of the existing literature, complete and consistent parameter sets are given for all materials. Emphasizing the quantities required for band structure calculations, we tabulate the direct and indirect energy gaps, spin orbit, and crystal field splittings, alloy bowing parameters, effective masses for electrons, heavy, light, and split off holes, Luttinger parameters, interband momentum matrix elements, and deformation potentials, including temperature and alloy composition dependences where available. Heterostructure band offsets are also given, on an absolute scale that allows any material to be aligned relative to any other.", "author_names": [ "Igor Vurgaftman", "Jerry R Meyer", "L R Ram-Mohan" ], "corpus_id": 121056857, "doc_id": "121056857", "n_citations": 5522, "n_key_citations": 105, "score": 0, "title": "Band parameters for III V compound semiconductors and their alloys", "venue": "", "year": 2001 }, { "abstract": "Contributors. Preface. Gallium Nitride (GaN) (V. Bougrov, et al. Aluminum Nitride (AIN) (Y. Goldberg) Indium Nitride (InN) (A. Zubrilov) Boron Nitride (BN) (S. Rumyantsev, et al. Silicon Carbide (SiC) (Y. Goldberg, et al. Silicon Germanium (Si 1 xGe x) (F. Schaffler) Appendix 1: Basic Physical Constants. Appendix 2: Periodic Table of the Elements. Appendix 3: Rectangular Coordinates for Hexagonal Crystal. Appendix 4: The First Brillouin Zone for Wurtzite Crystal. Appendix 5: Zinc Blende Structure. Appendix 6: The First Brillouin Zone for Zinc Blende Crystal. Additional References.", "author_names": [ "M E Levinshtein", "Sergey Rumyantsev", "Michael S Shur" ], "corpus_id": 136897631, "doc_id": "136897631", "n_citations": 1416, "n_key_citations": 52, "score": 0, "title": "Properties of advanced semiconductor materials GaN, AlN, InN, BN, SiC, SiGe", "venue": "", "year": 2001 }, { "abstract": "Silicon, germanium, and related alloys, which provide the leading materials platform of electronics, are extremely inefficient light emitters because of the indirect nature of their fundamental energy bandgap. This basic materials property has so far hindered the development of group IV photonic active devices, including diode lasers, thereby significantly limiting our ability to integrate electronic and photonic functionalities at the chip level. Here we show that Ge nanomembranes (i.e. single crystal sheets no more than a few tens of nanometers thick) can be used to overcome this materials limitation. Theoretical studies have predicted that tensile strain in Ge lowers the direct energy bandgap relative to the indirect one. We demonstrate that mechanically stressed nanomembranes allow for the introduction of sufficient biaxial tensile strain to transform Ge into a direct bandgap material with strongly enhanced light emission efficiency, capable of supporting population inversion as required for providing optical gain.", "author_names": [ "Jose R Sanchez-Perez", "Cicek Boztug", "Feng Chen", "Faisal F Sudradjat", "Deborah M Paskiewicz", "R B Jacobson", "Max G Lagally", "Roberto Paiella" ], "corpus_id": 25311288, "doc_id": "25311288", "n_citations": 193, "n_key_citations": 3, "score": 0, "title": "Direct bandgap light emitting germanium in tensilely strained nanomembranes", "venue": "Proceedings of the National Academy of Sciences", "year": 2011 }, { "abstract": "Semiconductor alloy nanowires with spatially graded compositions (and bandgaps) provide a new material platform for many new multifunctional optoelectronic devices, such as broadly tunable lasers, multispectral photodetectors, broad band light emitting diodes (LEDs) and high efficiency solar cells. In this review, we will summarize the recent progress on composition graded semiconductor alloy nanowires with bandgaps graded in a wide range. Depending on different growth methods and material systems, two typical nanowire composition grading approaches will be presented in detail, including composition graded alloy nanowires along a single substrate and those along single nanowires. Furthermore, selected examples of applications of these composition graded semiconductor nanowires will be presented and discussed, including tunable nanolasers, multi terminal on nanowire photodetectors, full spectrum solar cells, and white light LEDs. Finally, we will make some concluding remarks with future perspectives including opportunities and challenges in this research area.", "author_names": [ "Xiujuan Zhuang", "Cun-Zheng Ning", "Anlian Pan" ], "corpus_id": 205242437, "doc_id": "205242437", "n_citations": 86, "n_key_citations": 0, "score": 0, "title": "Composition and bandgap graded semiconductor alloy nanowires.", "venue": "Advanced materials", "year": 2012 }, { "abstract": "Abstract This paper presents simple but accurate closed form equations for Band Gap Narrowing (BGN) for n and p type, Si, Ge, GaAs and GexSi1 x alloys and strained layers. The equations are derived by identifying the four components of BGN: exchange energy shift of the majority band edge, correlation energy shift of the minority band edge and impurity interaction shifts of the two band edges. In the simple parabolic band approximation, the BGN is determined by the effective masses of the carriers and the relative permittivity of the semiconductor. For real semiconductors, known corrections due to anisotropy of the bands, due to multi valleys in a band and due to interactions between sub bands are used. The values of BGN for n Si, n Ge and n and p GaAs calculated using this simple formulation agree closely with the theoretical values calculated by other authors using advanced but complex many body methods and the Random Phase Approximation for screening effects. For p Si and p Ge ours appear to be the first calculations taking all interactions into account. Experimental values of BGN for all semiconductors except for p Ge for which no data could be found, are also in very good agreement with our theory. The Fermi level for n and p Si and p GaAs is determined using the published luminescence data. In heavily doped p type semiconductors, the values are found to be considerably smaller than those calculated using the known values of the effective density of states. The values of apparent BGN for n and p Si and p GaAs calculated using experimentally determined Fermi levels are in remarkably good agreement with the experimental values derived from device measurements. All results are presented in a form which lends itself to numerical computer simulation studies.", "author_names": [ "S C Jain", "David J Roulston" ], "corpus_id": 94170758, "doc_id": "94170758", "n_citations": 353, "n_key_citations": 9, "score": 0, "title": "A simple expression for band gap narrowing (BGN) in heavily doped Si, Ge, GaAs and GexSi1 x strained layers", "venue": "", "year": 1991 }, { "abstract": "In recent years, quantum dots have been successfully grown by self assembling processes. For optoelectronic device applications, the quantum dot structures have advantages such as reduced phonon scattering, longer carrier lifetime, and lower detector noise due to low dimensional confinement effect. Comparing to traditional optoelectronic III V and other materials, self assembled Ge quantum dots grown on Si substrates have a potential to be monolithically integrated with advanced Si based technology. In this paper, we describe the growth of self assembled, guided Ge quantum dots, and Ge quantum dot superlattices on Si. For dot growth, issues such as growth conditions and their effects on the dot morphology are reviewed. Then vertical correlation and dot morphology evolution are addressed in relation to the critical thickness of Ge quantum dot superlattices. In addition, we also discuss the quantum dot p i p photodetectors (QDIPs) and n i n photodetectors for mid infrared applications, and the quantum dot p i n photodetectors for 1.3 1.55 mum for communications applications. The wavelength of SiGe p i p QDIP can be tuned by the size as grown by various patterning methods. Photoresponse is demonstrated for an n i n structure in both the mid infrared and far infrared wavelength ranges. The p i n diodes exhibit low dark current and high quantum efficiency. The characteristics of fabricated light emitting diode (LED) devices are also discussed, and room temperature electroluminescence is observed for Ge quantum dot LED. The results indicate that Ge dot materials are potentially applicable for mid infrared (8 12 mum) detectors as well as fiber optic (1.3 1.55 mum) communications.", "author_names": [ "Kang L Wang", "Dongho Cha", "Jianlin Liu", "Christopher Chen" ], "corpus_id": 1526128, "doc_id": "1526128", "n_citations": 136, "n_key_citations": 0, "score": 0, "title": "Ge/Si Self Assembled Quantum Dots and Their Optoelectronic Device Applications", "venue": "Proceedings of the IEEE", "year": 2007 } ]

[ { "abstract": "This paper presents a brief review on job shop scheduling techniques in semiconductor manufacturing. The manufacturing environment in a semiconductor industry is considered a highly complex job shop, involving multiple types of work centers, large and changing varieties of products, sequence dependent setup times, reentrant process flow, etc. in a dynamic scheduling environment. Due to the stubborn nature of the deterministic job shop scheduling problem itself, many of the solutions proposed are of hybrid construction cutting across the traditional disciplines. The problem has been investigated from a variety of perspectives resulting in several analytical techniques combining generic as well as problem specific strategies. In this paper, we seek to provide a brief overview of the problem, the techniques used and the researchers involved in solving this problem.", "author_names": [ "Amit Kumar Gupta", "Appa Iyer Sivakumar" ], "corpus_id": 110831669, "doc_id": "110831669", "n_citations": 126, "n_key_citations": 5, "score": 0, "title": "Job shop scheduling techniques in semiconductor manufacturing", "venue": "", "year": 2006 }, { "abstract": "Abstract Simulation Optimization (SO) techniques refer to a set of methods that have been applied to stochastic optimization problems, structured so that the optimizer(s) are integrated with simulation experiments. Although SO techniques provide promising solutions for large and complex stochastic problems, the simulation model execution is potentially expensive in terms of computation time. Thus, the overall purpose of this research is to advance the evolutionary SO methods literature by researching the use of metamodeling within these techniques. Accordingly, we present a new Evolutionary Learning Based Simulation Optimization (ELBSO) method embedded within Ordinal Optimization. In ELBSO a Machine Learning (ML) based simulation metamodel is created using Genetic Programming (GP) to replace simulation experiments aimed at reducing computation. ELBSO is evaluated on a Stochastic Job Shop Scheduling Problem (SJSSP) which is a well known complex production planning problem in most industries such as semiconductor manufacturing. To build the metamodel from SJSSP instances that replace simulation replications, we employ a novel training vector to train GP. This then is integrated into an evolutionary two phased Ordinal Optimization approach to optimize an SJSSP which forms the ELBSO method. Using a variety of experimental SJSSP instances, ELBSO is compared with evolutionary optimization methods from the literature and typical dispatching rules. Our findings include the superiority of ELBSO over all other algorithms in terms of the quality of solutions and computation time. Furthermore, the integrated procedures and results provided within this article establish a basis for future SO applications to large and complex stochastic problems.", "author_names": [ "Amirreza Ghasemi", "Amir Ashoori", "Cathal Heavey" ], "corpus_id": 233544746, "doc_id": "233544746", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Evolutionary Learning Based Simulation Optimization for Stochastic Job Shop Scheduling Problems", "venue": "Appl. Soft Comput.", "year": 2021 }, { "abstract": "In this paper, we discuss scheduling problems in semiconductor manufacturing. Starting from describing the manufacturing process, we identify typical scheduling problems found in semiconductor manufacturing systems. We describe batch scheduling problems, parallel machine scheduling problems, job shop scheduling problems, scheduling problems with auxiliary resources, multiple orders per job scheduling problems, and scheduling problems related to cluster tools. We also present important solution techniques that are used to solve these scheduling problems by means of specific examples, and report on known implementations. Finally, we summarize some of the challenges in scheduling semiconductor manufacturing operations.", "author_names": [ "Lars Monch", "John W Fowler", "Stephane Dauzere-Peres", "Scott J Mason", "Oliver Rose" ], "corpus_id": 207202887, "doc_id": "207202887", "n_citations": 276, "n_key_citations": 16, "score": 1, "title": "A survey of problems, solution techniques, and future challenges in scheduling semiconductor manufacturing operations", "venue": "J. Sched.", "year": 2011 }, { "abstract": "In this paper, we discuss scheduling problems in semiconductor manufacturing. Starting from describing the manufacturing process, we identify typical scheduling problems that can be found in semiconductor manufacturing systems. We describe batch scheduling problems, job shop scheduling problems, scheduling problems with secondary resources, multiple orders per job scheduling problems, and scheduling problems related to cluster tools. We also present important solution techniques that are used to solve these scheduling problems by means of specific examples, and report on known implementations. Finally, we summarize some challenges in scheduling semiconductor manufacturing operations.", "author_names": [ "Lars Monch", "John W Fowler", "Stephane Dauzere-Peres", "Scott J Mason", "Oliver Rose" ], "corpus_id": 18962021, "doc_id": "18962021", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Scheduling Semiconductor Manufacturing Operations Problems Solution Techniques and Future Challenges", "venue": "", "year": 2009 }, { "abstract": "Lars MonchJohn W. FowlerStephane Dauzere PeresScott J. MasonOliver Rose Abstract In this paper, we discuss scheduling problems in semiconductor manufacturing. Starting from describing the manufacturing process, we identify typical scheduling problems that can be found in semiconductor manufacturing systems. We describe batch scheduling problems, job shop scheduling problems, scheduling problems with secondary resources, multiple orders per job scheduling problems, and scheduling problems related to cluster tools. We also present important solution techniques that are used to solve these scheduling problems by means of specific examples, and report on known implementations. Finally, we summarize some challenges in scheduling semiconductor manufacturing operations.", "author_names": [ "Lars Monch", "John W Fowler", "Stephane Dauzere-Peres", "Scott J Mason", "Oliver Rose" ], "corpus_id": 106416406, "doc_id": "106416406", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Scheduling Semiconductor Manufacturing Operations: Problems, Solution Techniques, and Future Challenges", "venue": "", "year": 2009 }, { "abstract": "In semiconductor manufacturing, it requires more than one objective such as cycle time, machine utilization and due date accuracy to be kept in focus simultaneously, while developing an effective scheduling. In this paper, a near optimal solution, which is not inferior to any other feasible solutions in terms of all objectives, is generated with a combination of the analytically optimal and simulation based scheduling approach. First, the job shop scheduling problem is modeled using the discrete event simulation approach and the problem is divided in to simulation clock based lot selection sub problems. Then, at each decision instant in simulated time, a Pareto optimal lot is selected using the various techniques to deal with multiobjective optimization such as weighted aggregation approach, global criterion method, minimum deviation method, and compromise programming. An illustration shows how these techniques work effectively in solving the multiobjective scheduling problem using discrete event simulation.", "author_names": [ "Amit Kumar Gupta", "Appa Iyer Sivakumar" ], "corpus_id": 13472979, "doc_id": "13472979", "n_citations": 42, "n_key_citations": 1, "score": 0, "title": "Simulation based multiobjective schedule optimization in semiconductor manufacturing", "venue": "Proceedings of the Winter Simulation Conference", "year": 2002 }, { "abstract": "In the current literature dealing with job shop scheduling, most of the approaches have developed models based on the assumption that the problem domain does not contain any imprecision. However, this hypothesis is strongly challenged in the implementation phase of such models imprecision is inherent to production systems involving human intervention. The aim of this paper is to demonstrate the advantages of possibilistic production data modeling in a real world application, i.e. semiconductor manufacturing. In this work, a discrete event simulation model (MELISSA) for performance evaluation of a batch manufacturing facility previously developed in our laboratory has been extended to treat uncertainties modeled by fuzzy numbers. Due to the confidential nature of industrial data, an illustrative example, presenting the same typical features as a real problem, is treated and analyzed using fuzzy concepts. Inclusion of fuzzy techniques provides the decision maker with a range of possible values for completion times, average storage times, and operator workload instead of a unique value (which has little significance due to the variety of human operators) In addition, the negative portion of average waiting times yields useful information for the manager to detect deficient resources in the production system.", "author_names": [ "Catherine Azzaro-Pantel", "Pascal Floquet", "Luc Pibouleau", "Serge Domenech" ], "corpus_id": 29143193, "doc_id": "29143193", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "A fuzzy approach for performance modeling in a batch plant: application to semiconductor manufacturing", "venue": "IEEE Trans. Fuzzy Syst.", "year": 1997 }, { "abstract": "This paper investigates a difficult scheduling problem on a specialized two stage hybrid flow shop with multiple processors that appears in semiconductor manufacturing industry, where the first and second stages process serial jobs and parallel batches, respectively. The objective is to seek job machine, job batch, and batch machine assignments such that makespan is minimized, while considering parallel batch, release time, and machine eligibility constraints. We first propose a mixed integer programming (MIP) formulation for this problem, then gives a heuristic approach for solving larger problems. In order to handle real world large scale scheduling problems, we propose an efficient dispatching rule called BFIFO that assigns jobs or batches to machines based on first in first out principle, and then give several reoptimization techniques using MIP and local search heuristics involving interchange, translocation and transposition among assigned jobs. Computational experiments indicate our proposed re optimization techniques are efficient. In particular, our approaches can produce good solutions for scheduling up to 160 jobs on 40 machines at both stages within 10 min.", "author_names": [ "I-Lin Wang", "Taho Yang", "Yu-Bang Chang" ], "corpus_id": 19164383, "doc_id": "19164383", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Scheduling two stage hybrid flow shops with parallel batch, release time, and machine eligibility constraints", "venue": "J. Intell. Manuf.", "year": 2012 }, { "abstract": "The authors present a strategy for shop level scheduling in a semiconductor wafer fabrication facility, which reduces WIP (work in process) and improves on time ship performance. Algorithms for lot release and lot dispatch are defined on the basis of dynamic programming techniques. The strategy is called flow rate control because it treats the production rates according to certain rules. The most important rule is the two boundary rule that consists of a simple inventory control policy and a simple surplus control policy. Development of the strategy was motivated by three features of the wafer manufacturing process: job re entry, the large number of machines and products, and random events such as machine failures and yield fluctuations. Two boundary control works by first forming a virtual job shop corresponding to the manufacturing process flow. Inventory and surplus levels are calculated for each job step and compared with predetermined values. These predetermined values are calculated from the failure rates and yield fluctuations of wafer fabrication. The loading rate at each job step in the wafer fabrication process is determined by the result of the comparison. An event driven simulator designed for job shop production simulation was used to compare the flow rate control strategy with other scheduling strategies. The results showed marked improvement in WIP levels and ship performance over these other approaches.<ETX>", "author_names": [ "Patrick Kager", "Sheldon X C Lou" ], "corpus_id": 111299198, "doc_id": "111299198", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Wafer fabrication scheduling using flow rate control strategy", "venue": "IEEE/SEMI International Semiconductor Manufacturing Science Symposium", "year": 1989 }, { "abstract": "Semiconductor manufacturing is a complicated flexible job shop scheduling problem (FJSP) of combinatorial complexity. Because of the adoption of advanced process control and advanced equipment control, the processing time in advanced wafer fabs become uncertain. Existing approaches considering constant processing time may not be appropriate to address the present problem in a real setting. In practice, processing times can be represented as intervals with the most probable completion time somewhere near the middle of the interval. A fuzzy number that is a generalized interval can represent this processing time interval exactly and naturally. This paper developed a hybrid approach integrating a particle swarm optimization algorithm with a Cauchy distribution and genetic operators (HPSO+GA) for solving an FJSP by finding a job sequence that minimizes the makespan with uncertain processing time. In particular, the proposed hybridized HPSO+GA approach employs PSO for creating operation sequences and assigning the time and resources for each operation, and then uses genetic operators to update the particles for improving the solution. To estimate the validity of the proposed approaches, experiments were conducted to compare the proposed approach with conventional approaches. The results show the practical viability of this approach. This paper concludes with discussions of contributions and recommends directions for future research.", "author_names": [ "Thitipong Jamrus", "Chen-Fu Chien", "Mitsuo Gen", "Kanchana Sethanan" ], "corpus_id": 10524353, "doc_id": "10524353", "n_citations": 62, "n_key_citations": 0, "score": 0, "title": "Hybrid Particle Swarm Optimization Combined With Genetic Operators for Flexible Job Shop Scheduling Under Uncertain Processing Time for Semiconductor Manufacturing", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2018 } ]

[ { "abstract": "As the primary prerequisite of capacity planning, inventory control and order management, demand forecast is a critical issue in semiconductor supply chain. A great quantity of stock keeping units (SKUs) with intermittent demand patterns and distinctive lead times need specific prediction respectively. It is difficult for companies in semiconductor supply chain to manage intricate inventory systems with the changeable nature of intermittent (lumpy) demand. This study aims to propose an integrated forecasting approach with recurrent neural network and parametric method for intermittent demand problems to support flexible decisions in inventory management, as a critical role in intelligent supply chain. An empirical study was conducted with product time series in a semiconductor company in Taiwan to validate the practicality of proposed model. The results suggest that the proposed hybrid model can improve forecast accuracy in demand management of semiconductor supply chain.", "author_names": [ "Wenhan Fu", "Chen-Fu Chien", "Zih-Hao Lin" ], "corpus_id": 52098864, "doc_id": "52098864", "n_citations": 9, "n_key_citations": 1, "score": 0, "title": "A Hybrid Forecasting Framework with Neural Network and Time Series Method for Intermittent Demand in Semiconductor Supply Chain", "venue": "APMS", "year": 2018 }, { "abstract": "Forecasts of product demand are essential for short and long term optimization of logistics and production. Thus, the most accurate prediction possible is desirable. In order to optimally train predictive models, the deviation of the forecast compared to the actual demand needs to be assessed by a proper metric. However, if a metric does not represent the actual prediction error, predictive models are insufficiently optimized and, consequently, will yield inaccurate predictions. The most common metrics such as MAPE or RMSE, however, are not suitable for the evaluation of forecasting errors, especially for lumpy and intermittent demand patterns, as they do not sufficiently account for, e.g. temporal shifts (prediction before or after actual demand) or cost related aspects. Therefore, we propose a novel metric that, in addition to statistical considerations, also addresses business aspects. Additionally, we evaluate the metric based on simulated and real demand time series from the automotive aftermarket.", "author_names": [ "Dominik Martin", "Phil Spitzer", "Niklas Kuhl" ], "corpus_id": 213694706, "doc_id": "213694706", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "A New Metric for Lumpy and Intermittent Demand Forecasts: Stock keeping oriented Prediction Error Costs", "venue": "HICSS", "year": 2020 }, { "abstract": "A number of time series methods 13 month simple moving average (SMA13) single exponential smoothing (SES) Croston's method, and the SyntetosBoylan approximation (SBA) are well referenced methods in the literature on intermittent or lumpy demand forecasting. We apply these four methods to an industrial dataset involving more than 1000 stockkeeping units (SKUs) in the central warehouse of a firm operating in the professional electronics sector. Earlier studies have argued that the negative binomial distribution (NBD) satisfies both theoretical and empirical criteria for modeling intermittent demand. We have found that the NBD often does not provide a good fit. We apply an alternative approach, using a two stage distribution involving the uniform and negative binomial distributions, in modeling actual demand. We use modeling and simulation to evaluate the four methods in terms of statistical forecast accuracy and, more importantly, inventory system efficiency.", "author_names": [ "Adriano O Solis", "Francesco Longo", "Letizia Nicoletti", "Aliaksandra Yemialyanava" ], "corpus_id": 68119817, "doc_id": "68119817", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Applying modeling and simulation to evaluate statistical accuracy and inventory control perfomance of lumpy demand forecasting methods", "venue": "", "year": 2013 }, { "abstract": "Advanced technical systems are complex machines that consist of several components. For these systems, it is important to forecasts defects and failure, which generate the demand for spare parts. Recently, Wang and Syntetos (2011) introduced a maintenance based model to forecast the intermittent and lumpy demand for spare parts. In this paper, we tested how well this model performs with aperiodic inspection intervals. We introduce a simple policy to create those aperiodic intervals. It turns out that the maintenance based model with aperiodic intervals performs as well as with periodic intervals. In most of the cases it outperforms the time series based benchmark.", "author_names": [ "T J J Bos" ], "corpus_id": 70301220, "doc_id": "70301220", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Forecasting spare parts demand for aperiodic inspection intervals", "venue": "", "year": 2018 }, { "abstract": "This study evaluates a number of methods in forecasting lumpy demand single exponential smoothing, Croston's method, the Syntetos Boylan approximation, an optimally weighted moving average, and neural networks (NN) The first three techniques are well referenced in the intermittent demand forecasting literature, while the last two are not traditionally used. We applied the methods on a time series dataset of lumpy demand. We found a simple NN model to be superior overall based on several scalefree forecast accuracy measures. Various studies have observed that demand forecasting performance with respect to standard accuracy measures may not translate into inventory systems efficiency. We simulate on the same dataset a periodic review inventory control system with forecast based order up to levels. We analyze resulting levels of on hand inventory, shortages, and fill rates, and discuss our findings and insights.", "author_names": [ "Adriano O Solis", "Somnath Mukhopadhyay", "Rafael S Gutierrez" ], "corpus_id": 157510271, "doc_id": "157510271", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Inventory control performance of various forecasting methods when demand is lumpy", "venue": "", "year": 2010 }, { "abstract": "In this paper we focus on forecasting for intermittent demand data. We propose a new aggregation framework for intermittent demand forecasting that performs aggregation over the demand volumes, in contrast to the standard framework that employs temporal (over time) aggregation. To achieve this we construct a transformed time series, the inverse intermittent demand series. The new algorithm is expected to work best on erratic and lumpy demand, as a result of the variance reduction of the non zero demands. The improvement in forecasting performance is empirically demonstrated through an extensive evaluation in more than 8000time series of two well researched spare parts data sets from the automotive and defence sectors. Furthermore, a simulation is performed so as to provide a stock control evaluation. The proposed framework could find popularity among practitioners given its suitability when dealing with clump sizes. As such it could be used in conjunction with existing popular forecasting methods for intermittent demand as an exception handling mechanism when certain types of demand are observed.", "author_names": [ "Fotios Petropoulos", "Nikolaos Kourentzes", "Konstantinos Nikolopoulos" ], "corpus_id": 31702465, "doc_id": "31702465", "n_citations": 27, "n_key_citations": 1, "score": 0, "title": "Another look at estimators for intermittent demand", "venue": "", "year": 2016 }, { "abstract": "Aircraft maintenance can be divided into routine and non routine activities. Material demand associated with non routine maintenance is typically intermittent or lumpy: it has a large variance in frequency and quantity. Consequently, this type of demand is hard to predict. This paper introduces a method to collect time series datasets for aircraft non routine maintenance material demand. Non routine material consumption is linked to scheduled maintenance tasks to gain insight in demand patterns. A structural part selection of the Boeing 737NG fleet of an aviation partner has been sampled to generate various test cases. Subsequently, various forecasting methods are applied to these test cases and evaluated using various accuracy metrics. For the small time series datasets associated with non routine maintenance, exponentially weighted moving average (EMA) outperformed smoothing methods such as Croston's method (CR) and the Syntetos Boylan approximation (SBA) To validate the practical applicability of EMA for non routine maintenance material demand, the method has been applied and verified in the prediction of actual demand for a separate maintenance C check.", "author_names": [ "M Zorgdrager", "Wim J C Verhagen", "Richard Curran" ], "corpus_id": 110019946, "doc_id": "110019946", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "An evaluation of forecasting methods for aircraft non routine maintenance material demand", "venue": "", "year": 2014 }, { "abstract": "Abstract Time series forecasting (TSF) is the task of predicting future values of a given sequence using historical data. Recently, this task has attracted the attention of researchers in the area of machine learning to address the limitations of traditional forecasting methods, which are time consuming and full of complexity. With the increasing availability of extensive amounts of historical data along with the need of performing accurate production forecasting, particularly a powerful forecasting technique infers the stochastic dependency between past and future values is highly needed. In this paper, we propose a deep learning approach capable to address the limitations of traditional forecasting approaches and show accurate predictions. The proposed approach is a deep long short term memory (DLSTM) architecture, as an extension of the traditional recurrent neural network. Genetic algorithm is applied in order to optimally configure DLSTM's optimum architecture. For evaluation purpose, two case studies from the petroleum industry domain are carried out using the production data of two actual oilfields. Toward a fair evaluation, the performance of the proposed approach is compared with several standard methods, either statistical or soft computing. Using different measurement criteria, the empirical results show that the proposed DLSTM model outperforms other standard approaches.", "author_names": [ "Alaa El Sagheer", "Mostafa Kotb" ], "corpus_id": 53237601, "doc_id": "53237601", "n_citations": 183, "n_key_citations": 8, "score": 1, "title": "Time series forecasting of petroleum production using deep LSTM recurrent networks", "venue": "Neurocomputing", "year": 2019 }, { "abstract": "Intermittent and fluctuating wind forces are detrimental to the grid. A multivariate model was proposed to improve the accuracy of wind power generation prediction in order to induce system operators to reduce risks. The model consists of three steps. First, the meteorological data such as wind speed are predicted by LSTM networks on the basis of traditional time series approaches. Then a method of similar time series matching with hierarchical search is proposed to highlight the main factors and save computing time. We use similar disparity as a criterion to select similar meteorological series and power data as training sets. Finally, similar data are inputted into LightGBM for modeling, training, and prediction. Industrial data of the wind power plant is examined case. The results are clearly display that the proposed method can effectively predict wind power in the next 6 hours and achieve high precision, which has certain engineering practical value.", "author_names": [ "Yukun Cao", "Liai Gui" ], "corpus_id": 57376417, "doc_id": "57376417", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Multi Step wind power forecasting model Using LSTM networks, Similar Time Series and LightGBM", "venue": "2018 5th International Conference on Systems and Informatics (ICSAI)", "year": 2018 }, { "abstract": "We present a novel approach to probabilistic time series forecasting that combines state space models with deep learning. By parametrizing a per time series linear state space model with a jointly learned recurrent neural network, our method retains desired properties of state space models such as data efficiency and interpretability, while making use of the ability to learn complex patterns from raw data offered by deep learning approaches. Our method scales gracefully from regimes where little training data is available to regimes where data from millions of time series can be leveraged to learn accurate models. We provide qualitative as well as quantitative results with the proposed method, showing that it compares favorably to the state of the art.", "author_names": [ "Syama Sundar Rangapuram", "Matthias W Seeger", "Jan Gasthaus", "Lorenzo Stella", "Bernie Wang", "Tim Januschowski" ], "corpus_id": 53991169, "doc_id": "53991169", "n_citations": 183, "n_key_citations": 23, "score": 0, "title": "Deep State Space Models for Time Series Forecasting", "venue": "NeurIPS", "year": 2018 } ]

[ { "abstract": "Energy and charge transfer processes in interacting donor acceptor systems are the bedrock of many fundamental studies and technological applications ranging from biosensing to energy storage and quantum optoelectronics. Central to the understanding and utilization of these transfer processes is having full control over the donor acceptor distance. With their atomic thickness and ease of integrability, two dimensional materials are naturally emerging as an ideal platform for the task. Here, we review how van der Waals semiconductors are shaping the field. We present a selection of some of the most significant demonstrations involving transfer processes in layered materials that deepen our understanding of transfer dynamics and are leading to intriguing practical realizations. Alongside current achievements, we discuss outstanding challenges and future opportunities.", "author_names": [ "Carlo Bradac", "Zai-Quan Xu", "Igor Aharonovich" ], "corpus_id": 231710433, "doc_id": "231710433", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Quantum Energy and Charge Transfer at Two Dimensional Interfaces.", "venue": "Nano letters", "year": 2021 }, { "abstract": "Increasing interest in using two dimensional transition metal dichalcogenides (2D TMDCs) in optical energy conversion technologies creates a demand for improving the yields and lifetimes of photogenerated charge carriers. Despite inherently fast photocarrier decay in neat 2D TMDCs, the unique photophysics in these quantum confined systems motivates continued effort to control the evolution of photoexcited states and create functional devices. An intriguing strategy to accomplish this goal is to employ TMDCs in heterojunctions with appropriate semiconductors, where energy level offsets drive photoinduced charge transfer (PCT) across material interfaces. PCT in TMDC based systems can be optimized for many different applications, such as driving free carriers to photocatalytic sites for redox reactions like water splitting, extracting charge to perform work in photovoltaics or photodetectors, and manipulating the spin and momentum valley electronic degrees of freedom for quantum computing systems. Here, we review recent strides in optimizing PCT for such applications through greater fundamental understanding of the photophysics that occurs at TMDC/semiconductor interfaces. After giving an overview of isolated TMDC properties, synthetic methods, and the basics of PCT, we discuss TMDCs in heterojunctions with several classes of materials, including other TMDCs, small molecule semiconductors, polymers, single walled carbon nanotubes, quantum dots, perovskites, and electrolytes. In addition to highlighting the unique benefits of each materials category, we also identify parallels across common themes, such as the roles of charge transfer states, spin, electronic coupling, delocalization, interfacial atomic morphology, and the precise design of energy landscapes to direct charge and energy motion. We hope to capture a broad range of the valuable work in this fast paced field to inspire new research directions for employing PCT in targeted TMDC based systems.", "author_names": [ "Dana B Sulas-Kern", "Elisa M Miller", "Jeffrey L Blackburn" ], "corpus_id": 225260308, "doc_id": "225260308", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Photoinduced charge transfer in transition metal dichalcogenide heterojunctions towards next generation energy technologies", "venue": "", "year": 2020 }, { "abstract": "Two dimensional transition metal dichalcogenide (2D TMD) semiconductors are new class of functional materials with a great promise for optoelectronics. Despite their atomic thickness, they strongly interact with light. This allows 2D TMDs to become suitable converters of photons into useful electric charges in heterostructures involving 2D TMDs and metallic nano plasmonics or semiconductor quantum dots (QDs) In this talk, I will illustrate how femtosecond pump probe spectroscopy can reveal a sub 45 fs charge transfer at a 2D/QDs heterostructure composed of tungsten disulfide monolayers (2D WS2) and a single layer of cadmium selenide (CdSe)/zinc sulfide (ZnS) core/shell 0D QDs. In another heterostructure involving 2D TMDs and plasmonics, I will describe how plasmons of an array of aluminum (Al) nanoantennas are excited indirectly via energy transfer from photoexcited exciton of 2D WS2 semiconductor. In particular, femtosecond spectroscopy measurements indicated that the lifetime of the resulting plasmon induced hot electrons in the Al array continue as long as that of the 2D WS2 excitons. Conversely, the presence of these excited plasmons almost triples the lifetime of the 2D WS2 excitons from ~15 to ~44 ps. This exciton plasmon coupling enabled by such hybrid nanostructures may open new opportunities for optoelectronic applications. This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. Synthesis of the two dimensional materials was supported by the Materials Science and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy.", "author_names": [ "Abdelaziz Boulesbaa", "Kai Wang", "Viktoriia E Babicheva", "Ivan I Kravchenko", "Ming-Wei Lin", "Masoud Mahjouri-Samani", "Mengkun Tian", "Alexander A Puretzky", "Ilia N Ivanov", "Christopher M Rouleau", "Bobby G Sumpter", "David B Geohegan" ], "corpus_id": 125125053, "doc_id": "125125053", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Ultrafast charge and energy exchanges at hybrid interfaces involving 2D semiconductors (Conference Presentation)", "venue": "LASE", "year": 2017 }, { "abstract": "In plane heterostructures of two dimensional transition metal dichalcogenides (TMDs) demonstrate the formation of one dimensional interfaces (or interlines) leading to new exciting properties and device functionalities. In this work, the interfacing effects have been studied in MoS2/WS2 quantum well and superlattice in plane heterostructures on the basis of first principles electronic calculations. In light of the orbital projected band structures, MoS2/WS2 in plane heterostructures illustrate type II band alignments with rather a small band offset for the valence band maximum and a relatively large band offset for the conduction band minimum. Upon increasing the width of TMD constituents, the band gap varies within a small range. In MoS2 and WS2, the surline energy and work function of zigzag edges with S terminations are obviously higher than those of metal terminations, and charge transfer from MoS2 to WS2 could be addressed due to the difference in the Fermi level. In gap levels induced by S vacancies in MoS2/WS2 in plane heterostructures are discrete and, interestingly, change to consecutive bands due to the built in electric field.", "author_names": [ "Wei Wei", "Ying Dai", "Baibiao Huang" ], "corpus_id": 31744613, "doc_id": "31744613", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "In plane interfacing effects of two dimensional transition metal dichalcogenide heterostructures.", "venue": "Physical chemistry chemical physics PCCP", "year": 2016 }, { "abstract": "Abstract Polar discontinuities occurring at interfaces between two materials constitute both a challenge and an opportunity in the study and application of a variety of devices. In order to cure the large electric field occurring in such structures, a reconfiguration of the charge landscape sets in at the interface via chemical modifications, adsorbates, or charge transfer. In the latter case, one may expect a local electronic doping of one material: one example is the two dimensional electron liquid (2DEL) appearing in SrTiO3 once covered by a polar LaAlO3 layer. Here, it is shown that tuning the formal polarization of a (La,Al)1 x(Sr,Ti)xO3 (LASTO:x) overlayer modifies the quantum confinement of the 2DEL in SrTiO3 and its electronic band structure. The analysis of the behavior in magnetic field of superconducting field effect devices reveals, in agreement with ab initio calculations and self consistent Poisson Schrodinger modeling, that quantum confinement and energy splitting between electronic bands of different symmetries strongly depend on the interface total charge densities. These results strongly support the polar discontinuity mechanisms with a full charge transfer to explain the origin of the 2DEL at the celebrated LaAlO3/SrTiO3 interface and demonstrate an effective tool for tailoring the electronic structure at oxide interfaces.", "author_names": [ "Danfeng Li", "S'ebastien Lemal", "Stefano Gariglio", "Zhenping Wu", "Alexandre Fete", "Margherita Boselli", "Philippe Ghosez", "J-M Triscone" ], "corpus_id": 52047108, "doc_id": "52047108", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "Probing Quantum Confinement and Electronic Structure at Polar Oxide Interfaces", "venue": "Advanced science", "year": 2018 }, { "abstract": "Solar fuel generation mediated by semiconductor heterostructures represents a promising strategy for sustainable energy conversion and storage. The design of semiconductor heterostructures for photocatalytic energy conversion requires the separation of photogenerated charge carriers in real space and their delivery to active catalytic sites at the appropriate overpotentials to initiate redox reactions. Operation of the desired sequence of light harvesting, charge separation, and charge transport events within heterostructures is governed by the thermodynamic energy offsets of the two components and their photoexcited charge transfer reactivity, which determine the extent to which desirable processes can outcompete unproductive recombination channels. Here, we map energetic offsets and track the dynamics of electron transfer in MoS2/CdS architectures, prepared by interfacing two dimensional MoS2 nanosheets with CdS quantum dots (QDs) and correlate the observed charge separation to photocatalytic activity in the hydrogen evolution reaction. The energetic offsets between MoS2 and CdS have been determined using hard and soft X ray photoemission spectroscopy (XPS) in conjunction with density functional theory. A staggered type II interface is observed, which facilitates electron and hole separation across the interface. Transient absorption spectroscopy measurements demonstrate ultrafast electron injection occurring within sub 5 ps from CdS QDs to MoS2, allowing for creation of a long lived charge separated state. The increase of electron concentration in MoS2 is evidenced with the aid of spectroelectrochemical measurements and by identifying the distinctive signatures of electron phonon scattering in picosecond resolution transient absorption spectra. Ultrafast charge separation across the type II interface of MoS2/CdS heterostructures enables a high Faradaic efficiency of ca. 99.4 1.2% to be achieved in the hydrogen evolution reaction (HER) and provides a 40 fold increase in the photocatalytic activity of dispersed photocatalysts for H2 generation. The accurate mapping of thermodynamic driving forces and dynamics of charge transfer in these heterostructures suggests a means of engineering ultrafast electron transfer and effective charge separation in order to design viable photocatalytic architectures.", "author_names": [ "Junsang Cho", "Nuwanthi Suwandaratne", "Sara Abdel Razek", "Yun-Hyuk Choi", "Louis F J Piper", "David F Watson", "Sarbajit Banerjee" ], "corpus_id": 221404465, "doc_id": "221404465", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Elucidating the Mechanistic Origins of Photocatalytic Hydrogen Evolution Mediated by MoS2/CdS Quantum Dot Heterostructures.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "The problem of a bound state of two particles confined to parallel two dimensional layers and interacting via dipole dipole or dipole charge laws arises in connection with the study of bound states of charge transfer excitons at parallel interfaces or biexcitons and charged exciton complexes in double quantum wells. Binding energies of the dipole charge and the dipole dipole complexes are calculated as functions of the corresponding coupling constants. It is shown that for the dipole charge interaction the bound state exists at an arbitrary small coupling constant, though the binding energy decreases dramatically when the coupling constant falls below some critical value. On the contrary, it is shown for the dipole dipole interaction that the bound state exists only when the coupling constant exceeds a critical value. @S0163 1829~97!05408 8#", "author_names": [ "Vladimir I Yudson", "M G Rozman", "P Reineker" ], "corpus_id": 56224198, "doc_id": "56224198", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Bound states of two particles confined to parallel two dimensional layers and interacting via dipole dipole or dipole charge laws", "venue": "", "year": 1997 }, { "abstract": "Interfacial electron transfer (ET) constitutes the key step in conversion of solar energy into electricity and fuels. Required for fast and efficient charge separation, strong donor acceptor interaction is typically achieved through covalent chemical bonding and leads to fast, adiabatic ET. Focusing on interfaces of pyrene, coronene, and a graphene quantum dot (GQD) with TiO2, we demonstrate the opposite situation: covalent bonding leads to weak coupling and nonadiabatic (NA) ET, while through space p electron interaction produces adiabatic ET. Using real time time dependent density functional theory combined with NA molecular dynamics, we simulate photoinduced ET into TiO2 from flat and vertically placed molecules and GQD containing commonly used carboxylic acid linkers. Both arrangements can be achieved experimentally with GQDs and other two dimensional materials, such as MoS2. The weak through bond donor acceptor coupling is attributed to the p electron withdrawing properties of the carboxylic acid group. The calculated ET time scales are in excellent agreement with pump probe optical experiments. The simulations show that the ET proceeds faster than energy relaxation. The electron couples to a broad spectrum of vibrational modes, ranging from 100 cm 1 large scale motions to 1600 cm 1 C C stretches. Compared to graphene/TiO2 heterojunctions, the molecule/TiO2 and GQD/TiO2 systems exhibit energy gaps, allowing for longer lived excited states and hot electron injection, facilitating charge separation and higher voltage. The reported state of the art simulations generate a detailed time domain, atomistic description of the interfacial charge and energy transfer and relaxation processes, and demonstrate that the fundamental principles leading to efficient charge separation in nanoscale materials depend strongly and often unexpectedly on the type of donor acceptor interaction. Understanding these principles is critical to the development of highly efficient photovoltaic and photocatalytic cells.", "author_names": [ "Run Long", "David Casanova", "Wei-Hai Fang", "Oleg V Prezhdo" ], "corpus_id": 207171226, "doc_id": "207171226", "n_citations": 71, "n_key_citations": 1, "score": 0, "title": "Donor Acceptor Interaction Determines the Mechanism of Photoinduced Electron Injection from Graphene Quantum Dots into TiO2: p Stacking Supersedes Covalent Bonding.", "venue": "Journal of the American Chemical Society", "year": 2017 }, { "abstract": "Design and characterization of molecular adsorbates for solar energy conversion Charge and exciton dynamics in semiconductor quantum dots: a time domain, ab initio view Multiscale modelling of interfacial electron transfer Plasmon enhanced solar chemistry: electrodynamics and quantum mechanics Charge carrier generation, separation, recombination and transport in nanostructured materials Two dimensional photon echo spectroscopy and energy transfer Ultrafast imaging and microscopy of energy conversion materials Ultrafast multiphoton photoemission microscopy of solid surfaces in the real and reciprocal space Light at the tip: hybrid scanning tunnelling/optical spectroscopy microscopy Time resolved IR spectroscopy of metal oxides and interfaces Carrier dynamics in photovoltaic structures and materials studied with time resolved terahertz spectroscopy Time resolved x ray absorption spectroscopy for solar energy research.", "author_names": [ "Piotr Piotrowiak" ], "corpus_id": 100238332, "doc_id": "100238332", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Solar energy conversion dynamics of interfacial electron and excitation transfer", "venue": "", "year": 2013 }, { "abstract": "During the last decade our expertise in nanotechnology has advanced considerably. The possibility of incorporating in the same nanostructure different organic and inorganic materials has opened up a promising field of research, and has greatly increased the interest in the study of properties of excitations in organic materials. In this book not only the fundamentals of Frenkel exciton and polariton theory are described, but also the electronic excitations and electronic energy transfers in quantum wells, quantum wires and quantum dots, at surfaces, at interfaces, in thin films, in multilayers, and in microcavities. Among the new topics in the book are those devoted to the optics of hybrid Frenkel Wannier Mott excitons in nanostructures, polaritons in organic microcavities including hybrid organic inorganic microcavities, new concepts for organic light emitting devices, the mixing of Frenkel and charge transfer excitons in organic quasi one dimensional crystals, excitons and polaritons in one and two dimensional crystals, surface electronic excitations, optical biphonons, and Fermi resonances by polaritons. All new phenomena described in the book are illustrated by available experimental observations. The book will be useful for scientists working in the field of photophysics and photochemistry of organic solids (for example, organic light emitting devices and solar cells) and for students who are entering this field. It is partly based on a book by the author written in 1968 \"Theory of Excitons\" in Russian. However the new book includes only 5 chapters from this version, all of which have been updated. The 10 new chapters contain discussions of new phenomena, their theory and their experimental observations.", "author_names": [ "Vladimir M Agranovich" ], "corpus_id": 135711561, "doc_id": "135711561", "n_citations": 142, "n_key_citations": 11, "score": 0, "title": "Excitations in organic solids", "venue": "", "year": 2008 } ]

[ { "abstract": "Concentrator photovoltaics (CPV) is a special high efficiency system technology in the world of PV technologies. The idea of CPV is to use optical light concentrators to increase the incident power on solar cells. The solar cell area is comparatively tiny, thus saving expensive semiconductor materials and allowing the use of more sophisticated and more costly multi junction solar cells. The highest CPV module efficiency achieved is 38.9% This CPV module uses four junction III V based solar cells. Moreover, mini modules have already achieved an efficiency of 43.4% The interaction between optics, cells, and layout of the module and tracker determines the overall field performance. Today, some utility scale CPV plants are installed. The CPV technology allows for many technical solutions for system designs and for optimizing performance while maintaining the economics. This paper will review the achievements and discuss the challenges for the CPV module technology and its components. We discuss the different components and the most important effects regarding the module design. Furthermore, we present the module designs that have shown the highest efficiencies.Concentrator photovoltaics (CPV) is a special high efficiency system technology in the world of PV technologies. The idea of CPV is to use optical light concentrators to increase the incident power on solar cells. The solar cell area is comparatively tiny, thus saving expensive semiconductor materials and allowing the use of more sophisticated and more costly multi junction solar cells. The highest CPV module efficiency achieved is 38.9% This CPV module uses four junction III V based solar cells. Moreover, mini modules have already achieved an efficiency of 43.4% The interaction between optics, cells, and layout of the module and tracker determines the overall field performance. Today, some utility scale CPV plants are installed. The CPV technology allows for many technical solutions for system designs and for optimizing performance while maintaining the economics. This paper will review the achievements and discuss the challenges for the CPV module technology and its components. We discuss the differen.", "author_names": [ "Maike Wiesenfarth", "Ignacio Anton", "Andreas W Bett" ], "corpus_id": 117148466, "doc_id": "117148466", "n_citations": 35, "n_key_citations": 0, "score": 1, "title": "Challenges in the design of concentrator photovoltaic (CPV) modules to achieve highest efficiencies", "venue": "", "year": 2018 }, { "abstract": "The world's oldest, and still functional, Concentrator Photovoltaic (CPV) power plant originally rated at 350 kW, and is situated 50 km from Riyadh, Saudi Arabia. There are ongoing efforts to retrofit the modules with new secondary optics and triple junction cell devices. The paper characterizes the initial optical train, whose design is non conventional in its use of a two area primary Fresnel lens. The first generation of a retrofit receiver package is described. Challenges beyond the optical design are encountered, including tracking and structural mechanics.The world's oldest, and still functional, Concentrator Photovoltaic (CPV) power plant originally rated at 350 kW, and is situated 50 km from Riyadh, Saudi Arabia. There are ongoing efforts to retrofit the modules with new secondary optics and triple junction cell devices. The paper characterizes the initial optical train, whose design is non conventional in its use of a two area primary Fresnel lens. The first generation of a retrofit receiver package is described. Challenges beyond the optical design are encountered, including tracking and structural mechanics.", "author_names": [ "Hussameldin I Khonkar", "Fahad Radhi Alharbi", "Abdulaziz Alyahyah", "David C Miller", "R K Leutz" ], "corpus_id": 202918817, "doc_id": "202918817", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Optical element design for the retrofit of the world's first concentrator photovoltaic (CPV) power plant", "venue": "", "year": 2019 }, { "abstract": "Abstract A new configuration of a photovoltaic module and a solar thermoelectric generator in a hybrid system integrated with a microchannel heat sink has been developed. The photovoltaic module and the solar thermoelectric generator sandwich the microchannel heat sink, as they are exposed to concentrated solar radiation. This newly developed hybrid system is compared to that with a conventional configuration in which an ordinary thermoelectric generator is attached directly to the rear surface of the concentrator photovoltaic module. To evaluate the performance of the new system in comparison to the conventional one, an all inclusive three dimensional thermo fluid thermoelectric model has been developed. This model is numerically simulated and is validated with both experimental and numerical results. The findings of this study show that the new system generates more output power and can be operated at higher concentration ratios with even lower average solar cell temperatures than the conventional system. In the new configuration, the average solar cell temperature is approximately 77 degC and the total electrical output power is approximately 3.2 kW/m2 at a solar concentration ratio of 20 suns. However, the maximum possible working concentration ratio for the conventional design is 10 suns, where the solar cell temperature approaches the highest tolerable temperature of approximately 90 degC. Moreover, the total electrical output power is approximately 1.2 kW/m2. Furthermore, it is found that at CR_PV 20, the rate of the produced thermal energy is approximately 12 kW/m2, for the conventional design while the new design achieves 15, 22, and 30 kW/m2 for CR_STEG of 1, 10, and 20, respectively. These findings have greatly aided in identifying a new design that achieves the highest performance under concentrated solar irradiance.", "author_names": [ "Ahmed Abdo", "Shinichi Ookawara" ], "corpus_id": 196889128, "doc_id": "196889128", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Performance evaluation of a new design of concentrator photovoltaic and solar thermoelectric generator hybrid system", "venue": "Energy Conversion and Management", "year": 2019 }, { "abstract": "Abstract Dense array concentrator photovoltaic (DA CPV) system is facing large mismatch losses due to the highly concentrated non uniform radiation. In this paper, a novel rotational symmetry (RS) connection approach with two examples is proposed to reduce mismatch losses. The output performances of the two RS connections are compared with that of four conventional connections by using a two stage simulation method. The results indicate that under different illumination distributions and CPV cell's series resistances, the RS connection approach can dramatically reduce power losses. The proposed dichotomic rotational symmetry (DRS) and quartered rotational symmetry (QRS) connections can significantly improve the output characteristics of DA CPV modules. Compared with the conventional series parallel (SP) connections, the DRS and QRS connections can improve the conversion efficiency by at most 48% and 64.3% respectively. Meanwhile, the QRS connection exhibits smoother I V and P V curves, reducing the difficulty of system's maximum power point tracking (MPPT) and improving the stability of output performance with varying Gaussian illuminations. When considering the Joule heat losses generated from the series resistance of CPV cells, the RS connections can also achieve much higher conversion efficiencies than other conventional configurations.", "author_names": [ "Xinyu Pan", "Xing Ju", "Chao Chen Xu", "Xiaoze Du", "Yongping Yang" ], "corpus_id": 104306802, "doc_id": "104306802", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "A novel rotational symmetry (RS) connection approach for dense array concentrator photovoltaic (DA CPV) modules", "venue": "Energy Conversion and Management", "year": 2019 }, { "abstract": "In this paper, we present a design and optical simulation of a novel linear Fresnel lens. The lens can be applied to a concentrator photovoltaic (CPV) system as a primary optical element (POE) to increase the concentration ratio and improve the uniformity of irradiance distribution over the receiver. In addition, the CPV system can use the proposed lens as a concentrator without involving a secondary optical element (SOE) The designed lens, which is a combination of two linear Fresnel lenses placed perpendicular to each other, can collect and distribute the direct sunlight on two dimensions. The lens is first designed in the MATLAB program, based on the edge ray theorem, Snell's law, and the conservation of the optical path length, and then drawn in three dimensions (3D) by using LightToolsTM. Furthermore, in order to optimize the structure and investigate the performance of the lens, the ray tracing and the simulation are also performed in LightToolsTM. The results show that the newly designed lens can achieve a high concentration ratio of 576 times, a high optical efficiency of 82.4% an acceptable tolerance of 0.84deg, and high uniform irradiance of around 77% for both horizontal and vertical investigation lines over the receiver.", "author_names": [ "Thanh Tuan Pham", "Ngoc Hai Vu", "Seoyong Shin" ], "corpus_id": 117686711, "doc_id": "117686711", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Novel Design of Primary Optical Elements Based on a Linear Fresnel Lens for Concentrator Photovoltaic Technology", "venue": "Energies", "year": 2019 }, { "abstract": "Concentration photovoltaic (CPV) modules promise a more efficient, higher power output than traditional photovoltaic modules. This is achieved by concentrating sunlight onto a small 1 cm2 concentrator triple junction (CTJ) InGaP/InGaAs/Ge cell by using high quality precision optics. In order to achieve high energy performance and reliability, well thought out design decisions must be made in the development of a CPV module. This paper investigates the design of two CPV modules (Module I and II) which are based on the Sandia III Baseline Fresnel module. The investigation concentrated on the effect of the optimization of the optical design on the electrical performance characteristics of CTJ cells with good thermal dissipation. The best performance achieved by Module I was at 336 times operational concentration (Xo) which produced a Pmax of 10.29 W per cell, with cell and module efficiencies of 39% and 24% respectively. In the development of the second module (Module II) pre deployment criteria such as the CTJ cell and system components characteristics was used to eliminate faulty components from the system what was observed in Module I. Cell units that were optimized in Module II showed no form of degradation in their Current Voltage (I V) characteristics. The cell unit operating under optical misalignment showed a progressive degradation with long term operation in the field.", "author_names": [ "R D Schultz", "E Ernest van Dyk", "F J Vorster" ], "corpus_id": 59247716, "doc_id": "59247716", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "The optical design and performance of a concentrator photovoltaic module", "venue": "", "year": 2017 }, { "abstract": "Despite its highest efficiency, concentrated photovoltaic (CPV) technology is still finding its way into the current photovoltaic market which is saturated with conventional flat plate photovoltaic systems. CPV systems have a great performance potential as they utilize third generation multi junction solar cells. In the CPV system, the main aspect is its concentrating assembly design which affects not only its overall performance but also its operation and fabrication. Conventional CPV design targets to use individual solar concentrator for each solar cell. The main motivation of this chapter is to propose a novel concentrating assembly design for CPV that is able to handle multiple solar cells, without affecting their size, using single solar concentrator. Such proposed design, named as multicell concentrating assembly (MCA) will not only reduce the assembly efforts during CPV module fabrication, but it will also lower the overall system cost with simplified design. In this chapter, a detailed design methodology of multicell concentrating assembly (MCA) for CPV module is presented and developed with complete verification through ray tracing simulation and field experimentation.", "author_names": [ "Muhammad Burhan", "Muhammad Wakil Shahzad", "Kim ChoonNg" ], "corpus_id": 73683308, "doc_id": "73683308", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Multicell Design for Concentrated Photovoltaic (CPV) Module", "venue": "", "year": 2018 }, { "abstract": "This paper presents the project Concentrating Photovoltaic modules using advanced technologies and cells for highest efficiencies (CPVMatch) which is funded from the European Union's Horizon 2020 research and innovation programme. V multi junction solar cells and CPV modules. Concerning cells, novel wafer bonded four junction solar cells made of GaInP/GaAs//GaInAs/Ge are optimized with the target of reaching 48% efficiency under concentration at the end of the project. Moreover, multi junction solar cell technologies with advanced materials like ternary IV element mixtures (i.e. SiGeSn) and nanostructured anti reflective coatings are investigated. Concerning CPV modules the project focuses on both Fresnel based and mirror based technologies with a target efficiency of 40% under high concentrations beyond 800x. Achromatic Fresnel lenses for improved light management without secondary optics are investigated. In addition, smart, mirror based HCPV modules are developed, which include a new mirror based design, the integration of high efficiency, low cost DC/DC converters and an intelligent tracking sensor (PSD sensor) at module level. A profound life cycle and environmental assessment and the development of adapted characterization methods of new multi junction cells and HCPV modules complete the work plan of CPVMatch.This paper presents the project Concentrating Photovoltaic modules using advanced technologies and cells for highest efficiencies (CPVMatch) which is funded from the European Union's Horizon 2020 research and innovation programme. V multi junction solar cells and CPV modules. Concerning cells, novel wafer bonded four junction solar cells made of GaInP/GaAs//GaInAs/Ge are optimized with the target of reaching 48% efficiency under concentration at the end of the project. Moreover, multi junction solar cell technologies with advanced materials like ternary IV element mixtures (i.e. SiGeSn) and nanostructured anti reflective coatings are investigated. Concerning CPV modules the project focuses on both Fresnel based and mirror based technologies with a target efficiency of 40% under high concentrations beyond 800x. Achromatic Fresnel lenses for improved light management without secondary optics are investigated. In addition, smart, mirror based HCPV modules are developed, which include a new mirror based", "author_names": [ "Simon P Philipps", "Mathieu Baudrit", "Karla Hillerich", "Valentine Moreau", "Rolando Parmesani", "Eduardo Roman", "Gabriel Sala", "Bernd Schineller", "Gianluca Timo", "Andreas W Bett" ], "corpus_id": 208817145, "doc_id": "208817145", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "CPVMatch Concentrating photovoltaic modules using advanced technologies and cells for highest efficiencies", "venue": "", "year": 2016 }, { "abstract": "Concentrator Photovoltaic Thermoelectric (CPV TE) hybrid devices have the potential to address areas of limitation within concentrator photovoltaic devices, using the inherent flexibility and controllability of thermoelectrics. In this work, a full CPV TE module was designed and fabricated using commercial Primary and Secondary Optical Elements (POEs and SOEs respectively) The SOE CPV TE hybrid receivers were characterized prior to integration within the module, and connected into a string of three receivers. The acceptance angle of the POE SOE CPV TE hybrid module was experimentally characterized, and outdoor on tracker data was obtained at the University of Jaen. For the first time, the performance of CPV TE hybrid devices was evaluated within a 3 receiver string, and the efficiency of on sun TE cooling was investigated.A preliminary break even point was found at 0.3A, for active cooling verses non cooling for the CPV TE hybrid receivers. This highlights the future on sun performance increases possible with further optimised CPV TE module designs, including a low power regime for optimised TE operation.", "author_names": [ "Matthew Rolley", "Tracy K N Sweet", "Luka Eerens", "Juan P Ferrer-Rodriguez", "Eduardo F Fernandez" ], "corpus_id": 116241542, "doc_id": "116241542", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Experimental comparison of a III:V triple junction concentrator photovoltaic thermoelectric (CPV TE) hybrid module with commercial CPV and flat plate silicon modules", "venue": "", "year": 2018 }, { "abstract": "The current photovoltaic market is completely dominated by the conventional single junction PV panels, despite the fact that the highest energy efficiency of multi junction solar cells is in the form of concentrated photovoltaic (CPV) system. CPV technology has faced many challenges of reliability and performance since its conception. However, despite much improvement in design and reliability, CPV technology is still unable to gain the attention of customers and energy planners with its high performance potential. Due to its response to only solar beam radiations, CPV systems are believed to be only suitable to operate in clear sky weather conditions. That's why the current gigantic CPV systems are only designed to be installed in open desert regions. It is still lacking the same application scope which the conventional PV is experiencing. With the aim to boost its market potential, in this chapter, a compact CPV design is discussed with low cost but highly accurate performance, to be targeted to install at the rooftop of commercial and residential building in the urban region. In addition, the performance of CPV system is also evaluated and compared with the different conventional PV system in the tropical weather condition with low beam radiation availability.", "author_names": [ "Muhammad Burhan", "Muhammad Wakil Shahzad", "Kim Choon Ng" ], "corpus_id": 134999669, "doc_id": "134999669", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Concentrated Photovoltaic (CPV) From Deserts to Rooftops", "venue": "", "year": 2019 } ]

[ { "abstract": "Abstract Auger recombination (AR) is usually assumed to depend on the electron density n and the hole density p like n2p (or np2) But, there are deviations from these rules, mainly in degenerate semiconductors. Studying this case the following results were obtained: 1. Normal AR which is only possible in narrow gap semiconductors goes approximately as np. 2. Phonon assisted AR which predominates in \"normal\" gap semiconductors (Eg 1 eV) has the \"usual\" density dependence n2p. 3. Second order AR with two Auger electrons goes with n 7 3 p (instead of an expected dependence n3p) Moreover, the density dependence may be influenced by the screening of the Coulomb interaction and by the strength of the excitation.", "author_names": [ "Albert Haug" ], "corpus_id": 94512146, "doc_id": "94512146", "n_citations": 96, "n_key_citations": 0, "score": 1, "title": "Carrier density dependence of Auger recombination", "venue": "", "year": 1978 }, { "abstract": "We report on the temperature and carrier density dependence of non radiative recombination processes in an InAs/GaSb/InAs type II W laser emitting at 3.4 mm. The measurements were performed with a sub picosecond photoluminescence upconversion set up in a temperature range between 10 K and 300 K and with initial excited carrier densities in the range between 2.96 x 1018 cm 3 and 4.44 x 1019 cm 3. The excellent growth quality of the device is indicated by a Shockley Read Hall coefficient of 2.2 x 108 s 1 at 10 K and 1.1 x 108 s 1 at 300 K. The cubic Auger recombination (AR) coefficient decreases in a characteristic manner with increasing initial excited carrier density. From a convergence equation, we obtained a cubic AR coefficient C03 of 1.2 x 10 28 cm6 s 1 for low carrier densities at 200 K. For low temperatures, due to degenerate carrier population of valence and conduction bands, a sublinear increase of the reciprocal lifetime versus carrier density is measured. With rising temperature the sublinear increase becomes linear and at 300 K a quadratic AR coefficient C02 of 1.73 x 10 11 cm3 s 1 was determined.", "author_names": [ "Jan Oliver Drumm", "Birgit Vogelgesang", "G Hoffmann", "C Schwender", "N Herhammer", "Henning Fouckhardt" ], "corpus_id": 96074128, "doc_id": "96074128", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Temperature and carrier density dependence of Auger recombination in a 3.4 um InAs/GaSb/AlSb type II laser device", "venue": "", "year": 2002 }, { "abstract": "Nitride light emitting diodes are a promising solution for efficient solid state lighting, but their performance at high power is affected by the efficiency droop problem. Previous experimental and theoretical work has identified Auger recombination, a three particle nonradiative carrier recombination mechanism, as the likely cause of the droop. In this work, we use first principles calculations to elucidate the dependence of the radiative and Auger recombination rates on temperature, carrier density and quantum well confinement. Our calculated data for the temperature dependence of the recombination coefficients are in good agreement with experiment and provide further validation on the role of Auger recombination in the efficiency reduction. Polarization fields and phase space filling negatively impact device efficiency because they increase the operating carrier density at a given current density and increase the fraction of carriers lost to Auger recombination.", "author_names": [ "Emmanouil Kioupakis", "Qimin Yan", "Daniel Steiauf", "Chris G van de Walle" ], "corpus_id": 5039244, "doc_id": "5039244", "n_citations": 91, "n_key_citations": 1, "score": 0, "title": "Temperature and carrier density dependence of Auger and radiative recombination in nitride optoelectronic devices", "venue": "", "year": 2013 }, { "abstract": "The usual quadratic dependence of the reciprocal Auger lifetime on the carrier density holds only if either the doping density or the excitation density is strongly dominant. If neither quantity dominates, exponents smaller than 2 in the carrier density dependence are possible; there are observed in some experiments.", "author_names": [ "Albert Haug" ], "corpus_id": 119585721, "doc_id": "119585721", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Remarks on the carrier density dependence of Auger recombination", "venue": "", "year": 1988 }, { "abstract": "This study investigated the temperature dependence of the Auger recombination coefficient (C) in an InGaN/GaN blue multiple quantum well (MQW) light emitting diode structure at temperatures between 20 and 100degC. The temperature dependence of C was determined by fitting the measured external quantum efficiency (EQE) data using an analytical model or numerical simulation. In the analytical model, the carrier density in InGaN MQWs was assumed to be constant and independent of temperature. In contrast, the inhomogeneous carrier distribution in MQWs and its temperature dependent redistribution were included in the numerical simulation. When the analytical model was employed to fit the EQE curve, C decreased with increasing temperature. On the other hand, when the numerical simulation was employed, C increased steadily by ~31% as the temperature was increased from 20 to 100degC. We found that the temperature dependent carrier distribution is important to consider when determining the temperature dependence of the Auger recombination coefficient in InGaN MQW structures.", "author_names": [ "Han-Youl Ryu", "Geun-Hwan Ryu", "Chibuzo Onwukaeme", "Byongjin Ma" ], "corpus_id": 222169803, "doc_id": "222169803", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Temperature dependence of the Auger recombination coefficient in InGaN/GaN multiple quantum well light emitting diodes.", "venue": "Optics express", "year": 2020 }, { "abstract": "SUMMARY AND CONCLUSIONS In summary, we have measured and calculated Augerrates for a 4 mm band gap type II superlattice designed forsuppression of Auger recombination and intersubband ab sorption at room temperature. The calculated Auger rates,which include superlattice Umklapp processes, were ob tained using Fermi's golden rule for the transition rates andthe full temperature dependent, nonparabolic band structure.Umklapp processes, which provide roughly half of the totalAuger rate, are found to be necessary to describe the experi mental results. The experimental Auger rates were deter mined from time resolved PL upconversion as a function ofoptically injected carrier density and lattice temperature. Wefind excellent agreement between measured and calculatedrates for direct Auger transitions at all temperatures and car rier densities, which suggests that phonon assisted Augerprocesses do not contribute significantly to the overall non radiative recombination rate.As discussed in more detail in Ref. 12, the 300 K Augercoefficient of 2.9310", "author_names": [ "D J Jang", "Michael E Flatte", "C H Grein", "Jonathon T Olesberg", "Thomas C Hasenberg", "Thomas F Boggess" ], "corpus_id": 120412486, "doc_id": "120412486", "n_citations": 44, "n_key_citations": 0, "score": 0, "title": "TEMPERATURE DEPENDENCE OF AUGER RECOMBINATION IN A MULTILAYER NARROW BAND GAP SUPERLATTICE", "venue": "", "year": 1998 }, { "abstract": "This work reports on measurements of the Auger recombination coefficients in silicon wafers with pump probe thermoreflectance techniques operating at two different excitation rates: 250 kHz (low repetition rate) and 80 MHz (high repetition rate) The different excitation frequencies give rise to different thermoreflectance signals in the Si samples, which is ascribed to the excited number density in the conduction band. In the low repetition rate case, the excited carriers recombine via Auger processes before the next pump excitation is absorbed. However, in the high repetition rate case, the rate in which the pump excitations are absorbed at the sample surface is higher than the Auger recombination rate, indicating that the excited carrier densities in the high repetition rate experiments are much higher than in the low repetition rate measurements even though the pump fluences are comparable. This is ascribed to pulse accumulation in the high repetition rate measurements, and is quantified with rate equ.", "author_names": [ "Patrick E Hopkins", "Edward V Barnat", "Jose Luis Cruz-Campa", "Robert K Grubbs", "Murat Okandan", "Gregory Nolan Nielson" ], "corpus_id": 121746426, "doc_id": "121746426", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Excitation rate dependence of Auger recombination in silicon", "venue": "", "year": 2010 }, { "abstract": "From a systematic study of the threshold current density as a function of temperature and hydrostatic pressure, in conjunction with theoretical analysis of the gain and threshold carrier density, we have determined the wavelength dependence of the Auger recombination coefficients in InGaAsSb/GaSb quantum well lasers emitting in the 1.7 3.2 \\mu$m wavelength range. From hydrostatic pressure measurements, the non radiative component of threshold currents for individual lasers was determined continuously as a function of wavelength. The results are analysed to determine the Auger coefficients quantitatively. This procedure involves calculating the threshold carrier density based on device properties, optical losses, and estimated Auger contribution to the total threshold current density. We observe a minimum in the Auger rate around 2.1 \\mu$m. A strong increase with decreasing mid infrared wavelength 2 \\mu$m) indicates the prominent role of inter valence Auger transitions to the split off hole band (CHSH process) Above 2 \\mu$m, the increase with wavelength is approximately exponential due to CHCC or CHLH Auger recombination, limiting long wavelength operation. The observed dependence is consistent with that derived by analysing literature values of lasing thresholds for type I InGaAsSb quantum well diodes. Over the wavelength range considered, the Auger coefficient varies from a minimum of \\leq$ 1x10$ {16}$cm${4}$s$ 1} at 2.1 \\mu$m to ~8x10${16}$cm${4}$s$ 1} at 3.2 \\mu$m.", "author_names": [ "Timothy D Eales", "Igor P Marko", "Alfred Rodney Adams", "Jerry R Meyer", "Igor Vurgaftman", "Stephen J Sweeney" ], "corpus_id": 220250410, "doc_id": "220250410", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Quantifying Auger recombination coefficients in type I mid infrared InGaAsSb quantum well lasers", "venue": "", "year": 2020 }, { "abstract": "Superatom solids are promising for optoelectronic applications, owing to their tunable structural and electronic properties; yet, the electronic transport properties of these materials have been largely unexplored. Here, we report the Auger recombination dynamics of free carriers in two representative two dimensional superatomic semiconductors, Re6Se8Cl2 and Mo6S3Br6, studied using ultrafast terahertz photoconductivity measurements. The fast Auger recombination dynamics are characterized by a cubic dependence of the Auger rate on carrier density in Re6Se8Cl2 and a quadratic dependence in Mo6S3Br6. The effective lifetimes of Mo6S3Br6 0.5 ps) are over an order of magnitude shorter than those 20 ps) of Re6Se8Cl2. These results highlight the variability of the optoelectronic properties of different superatom solids.", "author_names": [ "Heejae Kim", "Kihong Lee", "Avalon H Dismukes", "Bonnie Choi", "Xavier Roy", "Xiaoyang Zhu", "Mischa Bonn" ], "corpus_id": 219431582, "doc_id": "219431582", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Charge carrier scattering and ultrafast Auger dynamics in two dimensional superatomic semiconductors", "venue": "", "year": 2020 }, { "abstract": "Carrier lifetime has been measured by the luminescence decay of a 1.3 mm InGaAsP layer excited by a mode locked YAG laser at 1.06 mm. The measurements have been done as a function of excitation intensity for nearly three orders of magnitude of carrier concentration (4x1016 2x1019 cm 3) and for different temperatures (between 32 and 346 K) At low and moderate carrier density, the lifetime t follows the variation with excitation of the theoretical radiative lifetime. At high carrier density (above 1018 cm 3) the carrier decay rate increases more rapidly than the radiative one and around room temperature this can be accounted for by an additional recombination mechanism whose variation with excitation is typical of an Auger process. The Auger coefficient (Ca=2.6x10 29 cm6 s 1) does not vary with temperature within experimental uncertainty. This suggests that though Auger recombination is for a large part responsible for the low T0 value of 1.3 mm InGaAsP lasers, the temperature dependence of the Auger coeff.", "author_names": [ "Bernard Sermage", "Niloy K Dutta" ], "corpus_id": 121283651, "doc_id": "121283651", "n_citations": 51, "n_key_citations": 0, "score": 0, "title": "Temperature dependence of carrier lifetime and Auger recombination in 1.3 mm InGaAsP", "venue": "", "year": 1985 } ]

[ { "abstract": "The heat dissipation has been rarely investigated in solar cells although it has a significant impact on their performance and reliability. For the first time, an extended three dimensional (3 D) simulation of heat distribution in perovskite solar cells is presented here. We use COMSOL Multiphysics to investigate the temperature distribution in conventional perovskite solar cells through a coupled optical electrical thermal modules. Wave optics module, semiconductor module, and heat transfer in solid module are coupled in COMSOL Multiphysics package to perform the simulation in 3 D wizard. The electrical behavior, optical absorption, and heat conduction or convection are considered to gain insight into heat dissipation across the cell. The simulation results suggest that the heat produced in the cell is best dissipated from the metallic contact where the PbI$_2$ defect forms because of oxidation or decomposition of the perovskite layer at moisture exposure. The generated heat varies significantly from the front FTO contact to bottom metallic electrode. The more heat dissipation and accumulation is observed at the junction and electrode sides too. In our simulations, we consider the Joule heating, nonradiative recombination heating, and heat flux in every layer of the cell and calculate the carrier's concentration, electric field distribution, Joule heating, Shockley Read Hall heating, total heat flux, and temperature distribution across the solar cell structure. The simulations reveal that the metallic contact must be selected as a highly heat conductive material in order to accelerate the heat dissipation on the bottom of the cell and to enhance the cell reliability against temperature increase under normal operation.", "author_names": [ "P Saxena", "Nima E Gorji" ], "corpus_id": 204190861, "doc_id": "204190861", "n_citations": 25, "n_key_citations": 0, "score": 1, "title": "COMSOL Simulation of Heat Distribution in Perovskite Solar Cells: Coupled Optical Electrical Thermal 3 D Analysis", "venue": "IEEE Journal of Photovoltaics", "year": 2019 }, { "abstract": "Summary Heat is crucial to the long term stability of perovskite solar cells (PVSCs) Herein, thermal stability of PVSCs based on metal oxide (MO) and polymer (P) was investigated. Firstly, chemical decomposition behavior of perovskite films was characterized and analyzed, revealing that chemically active MO would accelerate the decomposition of methylamine lead iodide (MAPbI3) Secondly, thermal induced stress, resulting from the mismatched thermal expansion coefficients of different layers of PVSCs, and its effect on the mechanical stability of perovskite films were studied. Combining experiment and simulation, we conclude that \"soft\" (low modulus) and thick >20 nm) interfacial layers offer better relaxation of thermal induced stress. As a result, PVSCs employing thick polymer interfacial layer offer a remarkably improved thermal stability. This work offers not only the degradation insight of perovskite films on different substrates but also the path toward highly thermal stable PVSCs by rational design of interfacial layers.", "author_names": [ "Weitao Yang", "Danming Zhong", "Minmin Shi", "Shaoxing Qu", "Hongzheng Chen" ], "corpus_id": 209388815, "doc_id": "209388815", "n_citations": 15, "n_key_citations": 0, "score": 1, "title": "Toward Highly Thermal Stable Perovskite Solar Cells by Rational Design of Interfacial Layer", "venue": "iScience", "year": 2019 }, { "abstract": "We have developed a model to calculate the temperature of an illuminated perovskite solar cell (PSC) under the forward bias and that of a shaded one under the reverse bias at different ambient conditions. The results show that the dissipated power due to the reverse bias P R B should be more than around 6 W to have a higher temperature in the shaded solar cell than that in the illuminated solar cell at the solar irradiance of 1000 W m 2, and this result is almost ambient temperature and wind velocity independent. It is also found that the generated thermal power due to the nonradiative recombination P R e c becomes significant at the open circuit voltage V o c condition, leading to illuminated solar cell temperature T c r higher than that at the short circuit current J s c condition by about 12.7 K, 13.3 K, and 13.9 K at the ambient temperatures of 270 K, 300 K, and 330 K, respectively. In addition, the influence of the thickness of the illuminated solar cell on its temperature at the V o c condition is investigated, which reveals that, by increasing the thickness from 100 nm to 300 nm, the solar cell temperature can increase by 20 K.We have developed a model to calculate the temperature of an illuminated perovskite solar cell (PSC) under the forward bias and that of a shaded one under the reverse bias at different ambient conditions. The results show that the dissipated power due to the reverse bias P R B should be more than around 6 W to have a higher temperature in the shaded solar cell than that in the illuminated solar cell at the solar irradiance of 1000 W m 2, and this result is almost ambient temperature and wind velocity independent. It is also found that the generated thermal power due to the nonradiative recombination P R e c becomes significant at the open circuit voltage V o c condition, leading to illuminated solar cell temperature T c r higher than that at the short circuit current J s c condition by about 12.7 K, 13.3 K, and 13.9 K at the ambient temperatures of 270 K, 300 K, and 330 K, respectively. In addition, the influence of the thickness of the illuminated solar cel.", "author_names": [ "Hooman Mehdizadeh-Rad", "Jai Singh" ], "corpus_id": 209980992, "doc_id": "209980992", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Simulation of perovskite solar cell temperature under reverse and forward bias conditions", "venue": "Journal of Applied Physics", "year": 2019 }, { "abstract": "Abstract A 3D simulation of optical photogenreation, electrical characteristics, and thermal/heat distribution across the structure of a perovskite solar cell with a reduced graphene oxide (RGO) contact is presented. COMSOL Multiphysics package has been used to solve the coupled optical electrical thermal modules for this hybrid cell where the RGO added as the bottom electrode instead of a conventional metallic contact to enhance the heat dissipation towards a higher device stability. The Wave Optic module, Semiconductor module, and Heat Transfer in Solid module were coupled and solved for the proper input parameter values taken from relevant literature. The optical photogeneration, current voltage characteristics, electric field and the thermal maps of the cell are presented. The RGO contact doesn't significantly impact on the optical and electrical output of the cell, but it accelerates the heat dissipation. The heat is mainly generated across the cell from the light absorption, Shockley Read Hall non radiative recombination, and Joule heating. Compared to the cell with the Au electrode, the RGO contacted cell is showing a minimized heat accumulation and gradient at the bottom junction of the RGO/Spiro interface which promises a thermal stability of the cell. The nan radiative and joule heat distribution also show a moderated density for the RGO contacted cell which are assigned to the high heat conductivity of the RGO layer compared to traditional metallic electrodes. Our simulations results are of the rarely presented thermal simulations for such devices and prove the superiority of graphene over plane metallic contacts for heat dissipation and thermodynamic aspect of a solar cell.", "author_names": [ "Soma Zandi", "P Saxena", "Nima E Gorji" ], "corpus_id": 213873605, "doc_id": "213873605", "n_citations": 26, "n_key_citations": 0, "score": 1, "title": "Numerical simulation of heat distribution in RGO contacted perovskite solar cells using COMSOL", "venue": "", "year": 2020 }, { "abstract": "Abstract A planar device structure Glass/FTO/TiO2/CH3NH3Pb(I1 xClx)3/Cu2O/Carbon with Chloride (Cl) doped CH3NH3PbI3 i.e. CH3NH3Pb(I1 xClx)3 as a light harvester (attributed to its enhanced thermal stability and film quality) was modeled and investigated using SCAPS 1D simulation software. The simulation results state that the device parameters are much influenced by absorber thickness and the defect in absorber and their optimum values were obtained to be 500 nm and 1 x 1015 cm 3 respectively. It was also observed that the defect at interface TiO2/CH3NH3Pb(I1 xClx)3 affects the photovoltaic performance more than the defect at Cu2O/CH3NH3Pb(I1 xClx)3 interface. Among the two defects i.e. substitution defect (NtMA) and oxygen vacancy (NtO) at TiO2/perovskite interface, NtMA has slightly greater impact than NtO. Therefore, a large attention should be given to TiO2/perovskite interface engineering to maintain the defect density less than or equal to 1 x 1011 cm 2 to get better device performance. Further, to get good results the acceptor concentration of Cu2O should be 1 x 1019 cm 3. Materials with work function 5eV for back contact and =4.4eV for front contact were found appropriate for the device. The optimum power conversion efficiency (PCE) of 18.97% has been obtained using 1D SCAPS simulation software. These results will provide a path leading towards development of low cost and highly efficient solar cell.", "author_names": [ "Shambhavi Rai", "B K Pandey", "D K Dwivedi" ], "corpus_id": 214347767, "doc_id": "214347767", "n_citations": 22, "n_key_citations": 0, "score": 1, "title": "Modeling of highly efficient and low cost CH3NH3Pb(I1 xClx)3 based perovskite solar cell by numerical simulation", "venue": "", "year": 2020 }, { "abstract": "Monte Carlo simulation (MCS) combined with the Metropolis algorithm has been performed to study the magnetocaloric effect (MCE) in the promising double perovskite (DP) Sr2CrIrO6 that has not so far been synthetized. This paper presents the global magneto thermodynamic behavior of Sr2CrIrO6 compound in term of MCE and discusses the behavior in comparison to other DPs. Thermal dependence of the magnetization has been investigated for different values of reduced external magnetic field. Thermal magnetic entropy and its change have been obtained. The adiabatic temperature change and the relative cooling power have been established. Through the obtained results, Sr2CrIrO6 DP could have some potential applications for magnetic refrigeration over a wide temperature range above room temperature and at large magnetic fields.", "author_names": [ "Omar El Rhazouani", "Amine Slassi", "Younes Ziat", "Abdelilah Benyoussef" ], "corpus_id": 99158120, "doc_id": "99158120", "n_citations": 13, "n_key_citations": 0, "score": 1, "title": "Magnetocaloric effect in Sr2CrIrO6 double perovskite: Monte Carlo simulation", "venue": "", "year": 2017 }, { "abstract": "Abstract Magnetocaloric effect (MCE) in double perovskite (DP) Sr2CrMoO6 has been investigated for low magnetic field change by using a Monte Carlo Simulation (MCS) in the framework of Ising model. Total magnetization and thermal derivative of the magnetization have been investigated. Magnetic entropy change has shown a significant extension around the transition temperature which is primordial for magnetic refrigeration. At transition temperature (TC) equal to 458 K the maximum of magnetic entropy change, the adiabatic temperature change and the Relative Cooling Power (RCP) have shown an increase from 1.427 to 2.582 J K g 1 K 1 from 5.43 to 8.71 K and from 18.33 to 28.62 J k g 1 respectively, for magnetic field changes 100 O e and 700 O e which is large for low magnetic field compared to other magnetocaloric materials. The Large MCE at low field makes Sr2CrMoO6 a very promising candidate for magnetic refrigeration above room temperature.", "author_names": [ "Omar El Rhazouani", "Amine Slassi" ], "corpus_id": 126303870, "doc_id": "126303870", "n_citations": 10, "n_key_citations": 0, "score": 2, "title": "Low field magnetocaloric effect in the double perovskite Sr2CrMoO6: Monte Carlo simulation", "venue": "", "year": 2017 }, { "abstract": "Molecular dynamics simulation has been performed on strontium titanate and barium zirconate ceramic materials to investigate their thermal physical and thermal transport properties. The intricate interatomic potentials can be reduced to pairwise interactions, which consist of Ionic interaction, short range repulsion, Van der Waals attraction and Morse covalent bonding. The potential parameters were parameterized to explain the thermal properties. Using these empirical potential parameters, the thermal expansion and thermal conductivity of the perovskite ceramic materials have been evaluated in the temperature range of 298 K 2000 K. Comparison between the two ceramic materials suggests that strontium titanate is slightly more expansible and possess a higher thermal conductivity than barium zirconate. The simulation results show good agreement with the experimental findings. Keyword: molecular dynamics simulation; strontium titanate; barium zirconate; thermal conductivity; thermal expansion;", "author_names": [ "Wen Fong Goha", "Sohail Aziz Khana", "T Yoona" ], "corpus_id": 195184308, "doc_id": "195184308", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "A STUDY OF THERMAL PROPERTIES OF PEROVSKITE CERAMIC MATERIALS VIA MOLECULAR DYNAMICS SIMULATION", "venue": "", "year": 2013 }, { "abstract": "Abstract The magnetocaloric effect in NdMnO3 perovskite is investigated by using the Monte Carlo simulations. The Curie temperature TC of NdMnO3 compound is deduced from the variation of the magnetization vs. the temperature with different values of external magnetic field. The variation of magnetization with the external magnetic field H is given. The specific heat with the temperature is established for different external magnetic field. The thermal magnetic entropy for different external magnetic field and different exchange interactions in NdMnO3 compound is obtained. The adiabatic temperature change is obtained. The relative cooling power with different external magnetic field is established. The magnetocaloric effect has been investigated from magnetization.", "author_names": [ "Rachid Masrour", "A Jabar", "Abdelilah Benyoussef", "Mohamed Hamedoun", "El Kebir Hlil" ], "corpus_id": 124412690, "doc_id": "124412690", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "Monte Carlo simulation study of magnetocaloric effect in NdMnO 3 perovskite", "venue": "", "year": 2016 }, { "abstract": "Hybrid organic inorganic perovskites are semiconductors with disordered structures and remarkable properties for photovoltaic applications. Many theoretical investigations have attempted to obtain structural models of the high temperature phases, but most of them are focused on the mobility of organic components and their implications in material properties. Herein we propose a set of geometric variables to evaluate the conformation of the inorganic framework at each phase of methylammonium lead iodide perovskite. We show that the analysis of these variables is required to ensure consistent structural models of the tetragonal phase. We explore the theoretical ingredients needed to achieve good models of this phase. Ab initio molecular dynamic simulation, under canonical ensemble at the experimental unit cell volume, leads to representative states of the phase. Under this scheme, PBE and van der Waals density functional approaches provide similar models of the tetragonal phase. We find that this perovskite.", "author_names": [ "Ana Lilian Montero-Alejo", "Eduardo Menendez-Proupin", "D Hidalgo-Rojas", "Pablo Palacios", "Perla Wahnon", "Jose C Conesa" ], "corpus_id": 53402567, "doc_id": "53402567", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Modeling of thermal effect on the electronic properties of photovoltaic perovskite CH3NH3PbI3: the case of tetragonal phase", "venue": "", "year": 2016 } ]

[ { "abstract": "A digital closed loop system design of a microelectromechanical systems (MEMS) disk resonator gyroscope (DRG) is proposed in this paper. Vibration models with non ideal factors are provided based on the structure characteristics and operation mode of the sensing element. The DRG operates in force balance mode with four control loops. A closed self excited loop realizes stable vibration amplitude on the basis of peak detection technology and phase control loop. Force to rebalance technology is employed for the closed sense loop. A high frequency carrier loaded on an anchor weakens the effect of parasitic capacitances coupling. The signal detected by the charge amplifier is demodulated and converted into a digital output for subsequent processing. Considering compatibility with digital circuits and output precision demands, a low passband sigma delta (SD) analog to digital converter (ADC) is implemented with a 111.8dB signal to noise ratio (SNR) The analog front end and digital closed self excited loop is manufactured with a standard 0.35 um complementary metal oxide semiconductor (CMOS) technology. The experimental results show a bias instability of 2.1 deg/h and a nonlinearity of 0.035% over the 400deg full scale range.", "author_names": [ "Yihang Wang", "Q Fu", "Yufeng Zhang", "Wenbo Zhang", "Dongliang Chen", "Liang Yin", "Xiao-wei Liu" ], "corpus_id": 211022309, "doc_id": "211022309", "n_citations": 14, "n_key_citations": 0, "score": 1, "title": "A Digital Closed Loop Sense MEMS Disk Resonator Gyroscope Circuit Design Based on Integrated Analog Front end", "venue": "Sensors", "year": 2020 }, { "abstract": "The EM SD (electromechanical sigma delta) approach is a concise and efficient way to realize the digital interface for micro electromechanical systems (MEMS) accelerometers. However, including a fixed MEMS element makes the synthesizing of the EM SD loop an intricate problem. The loop parameters of EM SD can not be directly mapped from existing electrical SD modulator, and the synthesizing problem relies an experience dependent trail and error procedure. In this paper, we provide a new point of view to consider the EM SD loop. The EM SD loop is analyzed in detail from aspects of the signal loop, displacement modulation path and digital quantization loop. By taking a separate consideration of the signal loop and quantization noise loop, the design strategy is made clear and straightforward. On this basis, a discrete time PID (proportional integral differential) loop compensator is introduced which enhances the in band loop gain and suppresses the displacement modulation path, and hence, achieves better performance in system linearity and stability. A fifth order EM SD accelerometer system was designed and fabricated using 0.35 mm CMOS BCD technology. Based on proposed architecture and synthesizing procedure, the design effort was saved, and the in band performance, linearity and stability were improved. A noise floor of 1 mg/Hz, with a bandwidth 1 kHz and a dynamic range of 140 dB was achieved.", "author_names": [ "Dongliang Chen", "Liang Yin", "Q Fu", "Wenbo Zhang", "Yihang Wang", "Guorui Zhang", "Yufeng Zhang", "Xiao-wei Liu" ], "corpus_id": 209490148, "doc_id": "209490148", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "A Straightforward Approach for Synthesizing Electromechanical Sigma Delta MEMS Accelerometers", "venue": "Sensors", "year": 2020 }, { "abstract": "A digital output Disk Resonator Gyroscope (DRG) on chip temperature compensation method based on virtual sensor is proposed in this paper. DRG is a combination of solid wave gyroscope and MEMS gyro.", "author_names": [ "Yihang Wang", "Xiao-wei Liu", "Yufeng Zhang", "Q Fu" ], "corpus_id": 225264866, "doc_id": "225264866", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "A digital output MEMS DRG on chip temperature compensation method based on virtual sensor", "venue": "", "year": 2020 }, { "abstract": "Abstract The pandemic outbreak of coronavirus disease 2019 (COVID 19) is rapidly spreading all over the world. Reports from China showed that about 20% of patients developed severe disease, resulting in a fatality of 4% In the past two months, we clinical immunologists participated in multi rounds of MDT (multidiscipline team) discussion on the anti inflammation management of critical COVID 19 patients, with our colleagues dispatched from Chinese leading PUMC Hospital to Wuhan to admit and treat the most severe patients. Here, from the perspective of clinical immunologists, we will discuss the clinical and immunological characteristics of severe patients, and summarize the current evidence and share our experience in anti inflammation treatment, including glucocorticoids, IL 6 antagonist, JAK inhibitors and choloroquine/hydrocholoroquine, of patients with severe COVID 19 that may have an impaired immune system.", "author_names": [ "Wen Zhang", "Yan Zhao", "Feng-chun Zhang", "Qian Wang", "Taisheng Li", "Zheng-yin Liu", "Jinglan Wang", "Yan Qin", "Xuan Zhang", "Xiaowei Yan", "Xiaofeng Zeng", "Shuyang Zhang" ], "corpus_id": 214716402, "doc_id": "214716402", "n_citations": 796, "n_key_citations": 33, "score": 1, "title": "The use of anti inflammatory drugs in the treatment of people with severe coronavirus disease 2019 (COVID 19) The Perspectives of clinical immunologists from China", "venue": "Clinical Immunology", "year": 2020 }, { "abstract": "Coagulopathy in Critical Illness with Covid 19 The authors describe a 69 year old man with Covid 19 diagnosed in January 2020 in Wuhan, China, along with two other critically ill patients with Covid 19 who were also seen in the same intensive care unit. Coagulopathy and antiphospholipid antibodies were seen in all three patients.", "author_names": [ "Meng Xiao", "Shulan Zhang", "Peng Xia", "Wei Cao", "Xin Ding", "Hongmin Zhang", "Chun-yao Wang", "Xuefeng Sun", "Ran Tian", "Wei Wu", "Dong Wu", "Jie Ma", "Dong Zhang", "Xiaowei Yan", "Xiang Zhou", "Jinglan Wang", "Bin Du", "Yan Qin", "Peng Gao", "Xuzhen Qin", "Yingchun Xu", "Wen Zhang", "Yongzhe Li", "Shuyang Zhang" ], "corpus_id": 215619906, "doc_id": "215619906", "n_citations": 1379, "n_key_citations": 25, "score": 0, "title": "Coagulopathy and Antiphospholipid Antibodies in Patients with Covid 19", "venue": "The New England journal of medicine", "year": 2020 }, { "abstract": "We perform a large scale RNA sequencing study to experimentally identify genes that are downregulated by 25 miRNAs. This RNA seq dataset is combined with public miRNA target binding data to systematically identify miRNA targeting features that are characteristic of both miRNA binding and target downregulation. By integrating these common features in a machine learning framework, we develop and validate an improved computational model for genome wide miRNA target prediction. All prediction data can be accessed at miRDB (http:/mirdb.org)", "author_names": [ "Weijun Liu", "Xiaowei Wang" ], "corpus_id": 58947893, "doc_id": "58947893", "n_citations": 249, "n_key_citations": 6, "score": 0, "title": "Prediction of functional microRNA targets by integrative modeling of microRNA binding and target expression data", "venue": "Genome Biology", "year": 2019 }, { "abstract": "Electrochemical nitrogen reduction reaction (NRR) over nonprecious metal and single atom catalysts has received increasing attention as a sustainable strategy to synthesize ammonia. However, the atomic scale regulation of such active sites for NRR catalysis remains challenging because of the large distance between them, which significantly weakens their cooperation. Herein, the utilization of regular surface cavities with unique microenvironment on graphitic carbon nitride as \"subnano reactors\" to precisely confine multiple Fe and Cu atoms for NRR electrocatalysis is reported. The synergy of Fe and Cu atoms in such confined subnano space provides significantly enhanced NRR performance, with nearly doubles ammonia yield and 54% increased Faradic efficiency up to 34% comparing with the single metal counterparts. First principle simulation reveals this synergistic effect originates from the unique Fe Cu coordination, which effectively modifies the N2 absorption, improves electron transfer, and offers extra redox couples for NRR. This work thus provides new strategies of manipulating catalysts active centers at the sub nanometer scale.", "author_names": [ "Xiaowei Wang", "Siyao Qiu", "Jianmin Feng", "Yueyu Tong", "Feng Zhou", "Qinye Li", "Li Song", "Shuangming Chen", "Kuang-Hsu Wu", "Panpan Su", "Sheng Ye", "Feng Hou", "Shi Xue Dou", "Hua Kun Liu", "Gao Qing Max Lu", "Chenghua Sun", "Jian Liu", "Ji Liang" ], "corpus_id": 221466781, "doc_id": "221466781", "n_citations": 36, "n_key_citations": 0, "score": 0, "title": "Confined Fe Cu Clusters as Sub Nanometer Reactors for Efficiently Regulating the Electrochemical Nitrogen Reduction Reaction.", "venue": "Advanced materials", "year": 2020 }, { "abstract": "The COVID 19 outbreak continues to threaten the health and life of people worldwide. It is an immediate priority to develop and test a computer aided detection (CAD) scheme based on deep learning (DL) to automatically localize and differentiate COVID 19 from community acquired pneumonia (CAP) on chest X rays. Therefore, this study aims to develop and test an efficient and accurate deep learning scheme that assists radiologists in automatically recognizing and localizing COVID 19. A retrospective chest X ray image dataset was collected from open image data and the Xiangya Hospital, which was divided into a training group and a testing group. The proposed CAD framework is composed of two steps with DLs: the Discrimination DL and the Localization DL. The first DL was developed to extract lung features from chest X ray radiographs for COVID 19 discrimination and trained using 3,548 chest X ray radiographs. The second DL was trained with 406 pixel patches and applied to the recognized X ray radiographs to localize and assign them into the left lung, right lung or bipulmonary. X ray radiographs of CAP and healthy controls were enrolled to evaluate the robustness of the model. Compared to the radiologists' discrimination and localization results, the accuracy of COVID 19 discrimination using the Discrimination DL yielded 98.71% while the accuracy of localization using the Localization DL was 93.03% This work represents the feasibility of using a novel deep learning based CAD scheme to efficiently and accurately distinguish COVID 19 from CAP and detect localization with high accuracy and agreement with radiologists.", "author_names": [ "Zheng Wang", "Ying Xiao", "Yong Li", "Jie Zhang", "Fanggen Lu", "Muzhou Hou", "Xiaowei Liu" ], "corpus_id": 221324073, "doc_id": "221324073", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "Automatically discriminating and localizing COVID 19 from community acquired pneumonia on chest X rays", "venue": "Pattern Recognition", "year": 2020 }, { "abstract": "A reconfigurable neural network vision sensor is proposed by using gate tunable photoresponse of van der Waals heterostructures. Early processing of visual information takes place in the human retina. Mimicking neurobiological structures and functionalities of the retina provides a promising pathway to achieving vision sensor with highly efficient image processing. Here, we demonstrate a prototype vision sensor that operates via the gate tunable positive and negative photoresponses of the van der Waals (vdW) vertical heterostructures. The sensor emulates not only the neurobiological functionalities of bipolar cells and photoreceptors but also the unique connectivity between bipolar cells and photoreceptors. By tuning gate voltage for each pixel, we achieve reconfigurable vision sensor for simultaneous image sensing and processing. Furthermore, our prototype vision sensor itself can be trained to classify the input images by updating the gate voltages applied individually to each pixel in the sensor. Our work indicates that vdW vertical heterostructures offer a promising platform for the development of neural network vision sensor.", "author_names": [ "Chen-Yu Wang", "Shi-Jun Liang", "Shuang Wang", "Pengfei Wang", "Zhu'an Li", "Zhongrui Wang", "Anyuan Gao", "Chen Pan", "Chuan Liu", "Jiaokun Liu", "Huafeng Yang", "Xiaowei Liu", "Wenhao Song", "Cong Wang", "Bin Cheng", "Xiaomu Wang", "Kunji Chen", "Zhenlin Wang", "Kenji Watanabe", "Takashi Taniguchi", "J Joshua Yang", "Feng Miao" ], "corpus_id": 212414734, "doc_id": "212414734", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Gate tunable van der Waals heterostructure for reconfigurable neural network vision sensor", "venue": "Science Advances", "year": 2020 }, { "abstract": "Significance Viruses pose a great threat to animal and plant health worldwide. Whereas most plant viruses only replicate in plant hosts, some also replicate in their animal (insect) vector. A detailed knowledge of host expansion will give a better understanding of virus evolution, and identification of virus and host components involved in this process can lead to new strategies to combat virus spread. Here, we reveal that a plant DNA virus has evolved to induce and recruit insect DNA synthesis machinery to support its replication in vector salivary glands. Our study sheds light on the understanding of TYLCV whitefly interactions and provides insights into how a plant virus may evolve to infect and replicate in an insect vector. Whereas most of the arthropod borne animal viruses replicate in their vectors, this is less common for plant viruses. So far, only some plant RNA viruses have been demonstrated to replicate in insect vectors and plant hosts. How plant viruses evolved to replicate in the animal kingdom remains largely unknown. Geminiviruses comprise a large family of plant infecting, single stranded DNA viruses that cause serious crop losses worldwide. Here, we report evidence and insight into the replication of the geminivirus tomato yellow leaf curl virus (TYLCV) in the whitefly (Bemisia tabaci) vector and that replication is mainly in the salivary glands. We found that TYLCV induces DNA synthesis machinery, proliferating cell nuclear antigen (PCNA) and DNA polymerase d (Pold) to establish a replication competent environment in whiteflies. TYLCV replication associated protein (Rep) interacts with whitefly PCNA, which recruits DNA Pold for virus replication. In contrast, another geminivirus, papaya leaf curl China virus (PaLCuCNV) does not replicate in the whitefly vector. PaLCuCNV does not induce DNA synthesis machinery, and the Rep does not interact with whitefly PCNA. Our findings reveal important mechanisms by which a plant DNA virus replicates across the kingdom barrier in an insect and may help to explain the global spread of this devastating pathogen.", "author_names": [ "Ya-Zhou He", "Yu-Meng Wang", "Tian-Yan Yin", "Elvira Fiallo-Olive", "Yinquan Liu", "Linda Hanley-Bowdoin", "Xiaowei Wang" ], "corpus_id": 220416895, "doc_id": "220416895", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "A plant DNA virus replicates in the salivary glands of its insect vector via recruitment of host DNA synthesis machinery", "venue": "Proceedings of the National Academy of Sciences", "year": 2020 } ]

[ { "abstract": "In this paper we report successful synthesis and magnetic properties of (Ca,Na)(Zn,Mn)2Sb2 as a new ferromagnetic dilute magnetic semiconductor (DMS) In this DMS material the concentration of magnetic moments can be controlled independently from the concentration of electric charge carriers that are required for mediating magnetic interactions between these moments. This feature allows us to separately investigate the effect of carriers and of spins on the ferromagnetic properties of this new DMS alloy, and particularly of the critical ferromagnetic behavior. We use modified Arrott plot technique to establish critical exponents b, g, and d of this alloy. We find that at low Mn concentrations 10 at. it is governed by short range 3D Ising behavior, with experimental values of b, g, and d very close to theoretical 3D Ising values of 0.325, 1.24, and 4.815. However, as the Mn concentration increases, this DMS material exhibits a mixed phase behavior, with g retaining its 3D Ising characteristics, but b crossing over to longer range mean field behavior.", "author_names": [ "Shuang-jiang Yu", "Xinyu Liu", "Guoqiang Zhao", "Yi Peng", "Xiancheng Wang", "Jianfa Zhao", "Wenmin Li", "Zheng Deng", "Jacek K Furdyna", "Yasutomo J Uemura", "Changqing Jin" ], "corpus_id": 212736896, "doc_id": "212736896", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Anomalous critical point behavior in dilute magnetic semiconductor (Ca,Na)(Zn,Mn)2Sb2", "venue": "Physical Review Materials", "year": 2020 }, { "abstract": "We study InSb:Mn polycrystals with different values of the Mn content. In these samples, two ferromagnetic phases have been found: MnSb nanoinclusions with TC 600 K and an InMnSb magnetic host with TC below 10 K. The magnetic field dependence obtained for the measured Hall resistance exhibits a nonlinear behavior within a wide temperature range. At high temperatures, such a behavior can be attributed to the existence of two types of charge carriers, namely, light and heavy holes. At temperatures below the Curie point of the InMnSb host, the anomalous Hall effect contributing to the nonlinearity of the Hall resistance has been observed. Ferromagnetic MnSb inclusions do not contribute to the anomalous Hall effect. They do not lead to any spin polarization of charge carriers owing to the Schottky barrier, which surrounds these inclusions and prevents their interaction with charge carriers. A method has been proposed for distinguishing the anomalous Hall component in the case where the Hall resistance includes a nonlinear contribution of a different nature.", "author_names": [ "E I Yakovleva", "L N Oveshnikov", "Alexey V Kochura", "Konstantin G Lisunov", "Erkki Lahderanta", "Boris A Aronzon" ], "corpus_id": 123538558, "doc_id": "123538558", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Anomalous hall effect in the In1 xMnxSb dilute magnetic semiconductor with MnSb inclusions", "venue": "", "year": 2015 }, { "abstract": "Within a Monte Carlo technique we examine critical properties of diluted bulk magnetic semiconductor (Ga,Mn)As modeled by a strongly diluted ferromagnetic Heisenberg spin \\frac{5}{2} system on a face centered cubic lattice. We assumed that 5\\ of Ga atoms is substituted by Mn atoms and the interaction between them is of the RKKY type. The considered system is randomly quenched and a double average was performed: firstly, over the Boltzmann probability distribution and secondly over 2048 configurations related to the quenched disorder. We estimated the critical temperature: $T_c=97\\pm6$ K, which is in agreement with the experiment. The calculated high value of critical exponent \\nu$ seems to point to a possibility of non universal critical behavior.", "author_names": [ "Piotr Tomczak", "Hung T Diep", "P Jablo'nski", "Henryk Puszkarski" ], "corpus_id": 119067905, "doc_id": "119067905", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Monte Carlo study of critical properties of strongly diluted magnetic semiconductor (Ga,Mn)As", "venue": "", "year": 2017 }, { "abstract": "Abstract We have investigated magnetic phase transitions for the dilute semiconductors Zn 1 x Mn 2+ x As 2 x =0, 0.23, 0.33) by estimating the spin spin relaxation times T 2 in the temperature range 113 360 K. From ZnMn 2 As 2 a critical anomaly in T 2 was found around T AF =175 K, consistent with anomalous behavior in magnetization observed previously. In Zn 1 x Mn 2+ x As 2 with x =0, 0.23 and 0.33, such an anomaly in T 2 was found at 225 and 235 K, respectively.", "author_names": [ "Sang Woon Ahn", "Seong Gi Min", "Hee-jae Kang", "Suhk Kun Oh" ], "corpus_id": 119597331, "doc_id": "119597331", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Electron spin spin relaxation in dilute magnetic semiconductor Zn1 xMn2+xAs2", "venue": "", "year": 2004 }, { "abstract": "", "author_names": [ "Zheng Deng", "Shuang-jiang Yu", "Xiancheng Wang", "Yasutomo J Uemura", "Changqing Jin" ], "corpus_id": 225277975, "doc_id": "225277975", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chemical pressure effect and anomalous critical behaviors of new type of diluted magnetic semiconductors with independently charge and spin doping", "venue": "", "year": 2020 }, { "abstract": "Based on local density functional calculations, we study the exchange interactions between magnetic dopants Cr, Mn, and Fe in the III V compounds GaAs, GaN, and AlN. We show the magnetic exchange interactions deviate strongly in behavior expected from simple models, and may explain the observed maximum in critical temperature with impurity concentration. Additionally the magnetism is responsible for a strong, short range attraction between the magnetic dopants, thus creating an anomalous effective alloy hamiltonian. This suggests that the impurities may aggregate into small nanoclusters of a few magnetic atoms.", "author_names": [ "Mark van Schilfgaarde", "Oleg N Mryasov" ], "corpus_id": 122630313, "doc_id": "122630313", "n_citations": 281, "n_key_citations": 0, "score": 0, "title": "Anomalous exchange interactions in III V dilute magnetic semiconductors", "venue": "", "year": 2001 }, { "abstract": "Abstract The critical magnetic behavior of a weakly ferromagnetic NiRh alloy is found found to resemble the anomalous behavior recently reported for dilute Fe in Pd. From the critical coefficient values, it is shown that in NiRh ,as in PdFe, the elementary moments involved in the Curie point transition are those of giant polarization clouds rather than of individual atoms.", "author_names": [ "W C Muellner", "James S Kouvel" ], "corpus_id": 98340527, "doc_id": "98340527", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Critical magnetic behavior of giant moments in NiRh", "venue": "", "year": 1974 }, { "abstract": "This focus issue of New Journal of Physics is devoted to the materials science of dilute magnetic semiconductors (DMS) A DMS is traditionally defined as a diamagnetic semiconductor doped with a few to several atomic per cent of some transition metal with unpaired d electrons. Several kinds of dopant dopant interactions can in principle couple the dopant spins leading to a ferromagnetic ground state in a dilute magnetic system. These include superexchange, which occurs principally in oxides and only between dopants with one intervening oxygen, and double exchange, in which dopants of different formal charges exchange an electron. In both of these mechanisms, the ferromagnetic alignment is not critically dependent on free carriers in the host semiconductor because exchange occurs via bonds. A third mechanism, discovered in the last few years, involves electrons associated with lattice defects that can apparently couple dopant spins. This mechanism is not well understood. Finally, the most desirable mechanism is carrier mediated exchange interaction in which the dopant spins are coupled by itinerant electrons or holes in the host semiconductor. This mechanism introduces a fundamental link between magnetic and electrical transport properties and offers the possibility of new spintronic functionalities. In particular electrical gate control of ferromagnetism and the use of spin polarized currents to carry signals for analog and digital applications. The spin light emitting diode is a prototypical device of this kind that has been extensively used to characterize the extent of spin polarization in the active light emitting semiconductor heterostructure. The prototypical carrier mediated ferromagnetic DMS is Mn doped GaAs. This and closely related narrow gap III V materials have been very extensively studied. Their properties are generally quite well understood and they have led to important insights into fundamental properties of ferromagnetic systems with strong spin orbit coupling. They have also led to the demonstration of a wide range of novel phenomena including some, like tunneling anisotropic magnetoresistance, which have subsequently been achieved in metal ferromagnetic systems. However despite considerable effort over many years the maximum Curie point achieved in (Ga,Mn)As is still less than 200 K. So unless some major new breakthrough is achieved these materials are unlikely to be of use for practical spin electronics technologies. In 2000, Dietl et al [1] published a seminal paper in which mean field theory was used to predict which of the common diamagnetic semiconductors would exhibit a Curie point above ambient if doped with 5 at. Mn and a hole concentration of 3.5 x 1020 cm 3. Of the many host semiconductors simulated, only ZnO and GaN were predicted to exhibit a critical temperature in excess of 300 K. Since 2000, high Tc DMS research has proliferated in both experimental and theoretical arenas. Many papers have been published containing claims of new DMS materials based largely on limited film growth, powder diffraction, and magnetometry. In these papers, a film which exhibits a hysteretic SQUID or VSM loop at 300 K and phase purity with only the host semiconductor detected by XRD are often claimed to be true ferromagnetic DMSs. Many of these papers are flawed because the criteria for a well defined DMS are much more extensive. These include: (i) a random dopant distribution, (ii) a well known and preferably unique charge state and preferentially a unique local structural environment for the dopant, (iii) a demonstrated coupling of the dopant spin to the host band structure, leading to spin polarization of the majority carriers, and (iv) a rational dependence of the saturation magnetization and Curie point on the magnetic dopant and carrier concentrations. Implicit in this list is that trivial causes of ferromagnetism, such as magnetic contamination and magnetic secondary phase formation, are eliminated. Yet, in many papers, the authors have not carried out the necessary control experiments and materials characterization to convincingly eliminate these possibilities. The former includes the growth of films without the magnetic dopant and the associated demonstration of the absence of ferromagnetism. Magnetic secondary phase formation is particularly problematic because in order to inject enough magnetic dopant to generate appreciable magnetization and spin polarization, one must often exceed the solid solubility of the dopant in the host. If the dopant is itself ferromagnetic in its elemental state, or if unintended magnetic products nucleate, spurious ferromagnetism will occur. Moreover, it is often a major analysis challenge to detect secondary phases when they consist of only a few per cent of the dopant; element specific spectroscopies such as x ray absorption have been invaluable in this task. Powder diffraction is not sufficiently sensitive for this level of analysis. Against this backdrop, this focus issue of New Journal of Physics now appears. The editors' principal goal in soliciting papers has been to encourage investigators to submit work in which the necessary experiments have been done to allow the material to be adequately characterized. This collection contains a mix of experimental and theoretical papers, and many different types of materials are covered. This focus issue thus constitutes a snapshot in time of a fast moving and fascinating field of materials physics. Reference [1] Dietl T, Ohno H, Matsukura F, Cibert J and Ferrand D 2000 Science 287 1019 Focus on Dilute Magnetic Semiconductors Contents The structural, optical and magnetic properties and anomalous Hall effect of InMnP:Zn epilayers Yoon Shon, Sejoon Lee, D Y Kim, T W Kang, Chong S Yoon, Eun Kyu Kim and Jeong Ju Lee Magnetic reversal under external field and current driven domain wall motion in (Ga,Mn)As: influence of extrinsic pinning K Y Wang, A C Irvine, J Wunderlich, K W Edmonds, A W Rushforth, R P Campion, C T Foxon, D A Williams and B L Gallagher Huge tunnelling anisotropic magnetoresistance in (Ga,Mn)As nanoconstrictions A D Giddings, O N Makarovsky, M N Khalid, S Yasin, K W Edmonds, R P Campion, J Wunderlich, T Jungwirth, D A Williams, B L Gallagher and C T Foxon Lithographically and electrically controlled strain effects on anisotropic magnetoresistance in (Ga,Mn)As E De Ranieri, A W Rushforth, K Vyborny, U Rana, E Ahmad, R P Campion, C T Foxon, B L Gallagher, A C Irvine, J Wunderlich and T Jungwirth Structure and magnetism of cobalt doped ZnO thin films M Ivill, S J Pearton, S Rawal, L Leu, P Sadik, R Das, A F Hebard, M Chisholm, J D Budai and D P Norton Role of charge carriers for ferromagnetism in cobalt doped rutile TiO2 T Fukumura, H Toyosaki, K Ueno, M Nakano and M Kawasaki Ab initio study of exchange constants and electronic structure in diluted magnetic group IV semiconductors Silvia Picozzi and Marjana Lezaic Phase coherent transport in (Ga,Mn)As D Neumaier, K Wagner, U Wurstbauer, M Reinwald, W Wegscheider and D Weiss Hydrogen interstitials mediated ferromagnetism in MnxGe1 x magnetic semiconductors Xin Xin Yao, Shi Shen Yan, Shu Jun Hu, Xue Ling Lin, Chong Han, Yan Xue Chen, Guo Lei Liu and Liang Mo Mei Electronic structures of magnetic semiconductors FeCr2Se4 and Fe0.5Cu0.5Cr2Se4 B I Min, Seung Su Baik, H C Choi, S K Kwon and J S Kang Investigation of pure and Co2+ doped ZnO quantum dot electronic structures using the density functional theory: choosing the right functional Ekaterina Badaeva, Yong Feng, Daniel R Gamelin and Xiaosong Li Magnetic properties of sol gel derived doped ZnO as a potential ferromagnetic semiconductor: a synchrotron based study N R S Farley, K W Edmonds, A A Freeman, G van der Laan, C R Staddon, D H Gregory and B L Gallagher Local electronic structure of Cr in the II VI diluted ferromagnetic semiconductor Zn1 xCrxTe M Kobayashi, Y Ishida, J I Hwang, G S Song, A Fujimori, C S Yang, L Lee, H J Lin, D J Huang, C T Chen, Y Takeda, K Terai, S I Fujimori, T Okane, Y Saitoh, H Yamagami, K Kobayashi, A Tanaka, H Saito and K Ando Lack of ferromagnetism in n type cobalt doped ZnO epitaxial thin films T C Kaspar, T Droubay, S M Heald, P Nachimuthu, C M Wang, V Shutthanandan, C A Johnson, D R Gamelin and S A Chambers XMCD studies on Co and Li doped ZnO magnetic semiconductors Thomas Tietze, Milan Gacic, Gisela Schutz, Gerhard Jakob, Sebastian Bruck and Eberhard Goering Ferromagnetic semiconductors and the role of disorder B W Wessels An extensive comparison of anisotropies in MBE grown (Ga,Mn)As material C Gould, S Mark, K Pappert, R G Dengel, J Wenisch, R P Campion, A W Rushforth, D Chiba, Z Li, X Liu, W Van Roy, H Ohno, J K Furdyna, B Gallagher, K Brunner, G Schmidt and L W Molenkamp Local structural, magnetic and magneto optical properties of Mn doped SiC films prepared on a 3C SiC(001) wafer Wenhong Wang, Fumiyoshi Takano, Hironori Ofuchi and Hiro Akinaga Effects of proton irradiation on the magnetic properties of GaGdN and GaCrN J K Hite, K K Allums, G T Thaler, C R Abernathy, S J Pearton, R M Frazier, R Dwivedi, R Wilkins and J M Zavada", "author_names": [ "Scott A Chambers", "B L Gallagher" ], "corpus_id": 119528702, "doc_id": "119528702", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Focus on Dilute Magnetic Semiconductors", "venue": "", "year": 2008 }, { "abstract": "for an Invited Paper for the MAR05 Meeting of The American Physical Society Nanometer Scale Structure and Properties of Dilute Semiconductor Alloys RACHEL S. GOLDMAN, University of Michigan For many compound semiconductors, the addition of dilute concentrations of impurities leads to dramatic changes in the electronic, optical, and magnetic properties. For example, the introduction of a few percent nitrogen into GaAs leads to a band gap reduction of 100s of meV. Furthermore, the incorporation of a few percent manganese into GaAs enables a combination of semiconducting and ferromagnetic behavior. The resulting dilute semiconductor alloys are promising for several applications ranging from long wavelength light emitters and high efficiency solar cells to spin electronics and spin optoelectronics. In both cases, the nanometer scale details of impurity incorporation are critical to understanding and controlling the observed properties. In this talk, I will discuss our recent investigations of the growth, nanometer scale structure, and properties of dilute GaAsN and GaMnAs alloys, using nuclear reaction analysis and scanning tunneling microscopy, in conjunction with several other measurements. In GaAsN, we examine the role of surface reconstruction on the incorporation of nitrogen into substitutional vs. interstitial lattice sites, as well as the effect of nitrogen incorporation mechanisms on electronic and optical properties [1] In the case of GaMnAs, we quantify clustering of MnGa and AsGa point defects, and its effect on electronic and magnetic properties [2] [1] M. Reason, H. McKay, W. Ye, S. Hanson, V. Rotberg, and R.S. Goldman, \"Mechanisms of Nitrogen Incorporation in GaAsN Alloys,\" Appl. Phys. Lett. 85, 1692 (2004) [2] J.N. Gleason, M. Hjelmstad, V.D. Dasika, R.S. Goldman, S. Fathpour, S. Charkrabarti, and P.K. Bhattacharya, \"Nanometer scale Studies of Point Defect Distributions in GaMnAs Alloys,\" Appl. Phys. Lett. in press (January 3, 2005)", "author_names": [ "Michael Hjelmstad" ], "corpus_id": 4686806, "doc_id": "4686806", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nanometer Scale Structure and Properties of Dilute Semiconductor Alloys", "venue": "", "year": 2005 }, { "abstract": "The purpose of this study was to investigate the magnetotransport properties of the Ge0.743Pb0.183Mn0.074Te mixed crystal. The results of magnetization measurements indicated that the compound is a spin glass like diluted magnetic semiconductor with critical temperature TSG 97.5 K. Nanoclusters in the sample are observed. Both, matrix and clusters are magnetically active. Resistivity as a function of temperature has a minimum at 30 K. Below the minimum a variable range hopping is observed, while above the minimum a metallic like behavior occurs. The crystal has high hole concentration, p 6.6x 10 cm 3, temperature independent. Magnetoresistance amplitude changes from 0.78 to 1.18% with increase of temperature. In the magnetotransport measurements we observed the anomalous Hall e ect with hysteresis loops. Calculated anomalous Hall e ect coe cient, RS 2.0x 10 m/C, is temperature independent. The analysis indicates the extrinsic skew scattering mechanism to be the main physical mechanism responsible for anomalous Hall e ect in Ge0.743Pb0.183Mn0.074Te alloy.", "author_names": [ "A Podgorni", "L Kilanski", "Witold Dobrowolski", "Malgorzata Gorska", "Viktor Domukhovski", "B Brodowska", "Anna Reszka", "Bogdan J Kowalski", "V E Slynko", "E I Slynko" ], "corpus_id": 124835732, "doc_id": "124835732", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Anomalous Hall Effect in Ge1 x yPbxMnyTe Composite System", "venue": "", "year": 2014 } ]

[ { "abstract": "Multi level inverters are becoming very popular nowadays due to the usage of low rating devices for high rating applications, which overcome the limitation imposed by the rating of the semiconductor switches. In this paper, a comparative study of three different SPWM techniques for five level cascaded inverter is presented. Simulink is used for simulation. Simulation results; waveforms and THD graphs are obtained. Harmonics of three SPWM techniques are tabulated for comparison.", "author_names": [ "K Savyasachi G", "Avinash R", "P Rakshith", "K Apoorva G" ], "corpus_id": 113089606, "doc_id": "113089606", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Comparison of Three Sinusoidal Pulse Width Modulation Techniques for Five Level Cascaded Inverter using Simulink", "venue": "", "year": 2015 }, { "abstract": "This work presents the comparison of hybrid carrier Pulse Width Modulation (PWM) techniques for the chosen three phase Cascaded Multi Level Inverter (CMLI) In this paper, a CMLI is controlled with Sinusoidal PWM technique with Alternative Phase Opposition and Disposition and Carrier Overlapping (APOD CO) Alternative Phase Opposition and Disposition and Phase Shift (APOD PS) Alternative Phase Opposition and Disposition and Variable Frequency (APOD VF) CO VF, CO PS, Phase Disposition and Variable Frequency (PD VF) PS PD, PS VF APOD PD and CO PD and the variation of Total Harmonic Distortion (THD) in the outputs is observed for various modulation indices ma. Simulation is performed using MATLAB SIMULINK. It is seen that sinusoidal reference with PS+PD provides output with relatively low distortion. CO+VF PWM strategy is found to perform better since it provides relatively higher fundamental RMS output voltage and relatively lower stress on the devices.", "author_names": [ "Chinnapettai Ramalingam Balamurugan", "Sirukarumbur Pandurangan Natarajan", "R Bensraj" ], "corpus_id": 17566689, "doc_id": "17566689", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Comparative study on various bipolar hybrid carrier PWM strategies for three phase five level cascaded inverter", "venue": "2013 International Conference on Circuits, Power and Computing Technologies (ICCPCT)", "year": 2013 }, { "abstract": "This work presents the comparison of Inverted Sine Carrier Pulse Width Modulation (ISCPWM) techniques for a Cascaded Multi Level Inverter (CMLI) In this paper, the chosen three phase CMLI is controlled by Sinusoidal PWM (SPWM) reference and Third Harmonic Injection PWM (THI PWM) reference with Inverted Sine Carrier (ISC) and the variation of Total Harmonic Distortion (THD) in the output voltage is observed for various modulation indices. Simulation is performed using MATLAB SIMULINK. It is observed that sinusoidal reference with ISCPDPWM provides output with relatively low distortion. It is also seen that SPWM strategy with ISCCOPWM is found to perform better since it provides relatively higher fundamental RMS output voltage and relatively lower stress on the devices. From hardware results it is seen that ISCPDPWM provides output with relatively low distortion. It is also observed that ISCCOPWM is found to perform better since it provides relatively higher fundamental RMS output voltage.", "author_names": [ "C Murugan", "Sirukarumbur Pandurangan Natarajan", "R Bensraj" ], "corpus_id": 195749942, "doc_id": "195749942", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "dSPACE BASED IMPLEMENTATION OF VARIOUS INVERTED SINE CARRIER PWM STRATEGIES FOR THREE PHASE FIVE LEVEL H BRIDGE INVERTER", "venue": "", "year": 2016 }, { "abstract": "This paper presents the comparison of various Carrier Overlapping Pulse Width Modulation (COPWM) Strategies for the chosen three phase Cascaded Multi Level Inverter (CMLI) Various new schemes adopting the constant switching frequency and also variable switching frequency multicarrier control freedom degree combination concepts are developed and simulated for the chosen three phase CMLI. The three phase CMLI, is controlled in this paper with Sinusoidal PWM (SPWM) reference along with Carrier Overlapping (CO) techniques and simulation is performed using MATLAB SIMULINK. The variation of fundamental RMS output voltage and total harmonic distortion is observed for various carrier overlapping techniques. Among the various equal amplitude carrier overlapping techniques such as COPWM 1, COPWM 2, COPWM 3, and COPWM 4, it is observed that COPWM 3 provides less Total Harmonic Distortion (THD) and COPWM 4 provides relatively higher RMS voltage. Among the various Variable Amplitude COPWM (VACOPWM) techniques such as VACOPWM 1, VACOPWM 2, VACOPWM 3, and VACOPWM 4, it is inferred that VACOPWM 3 provides less THD and VACOPWM 2 and VACOPWM 3 provide higher RMS voltage. It also found that VACOPWM strategies perform better than corresponding COPWM strategies.", "author_names": [ "Chinnapettai Ramalingam Balamurugan", "Sirukarumbur Pandurangan Natarajan", "M Arumugam" ], "corpus_id": 14180636, "doc_id": "14180636", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "NEW VARIABLE AMPLITUDE CARRIER OVERLAPPING PWM METHODS FOR THREE PHASE FIVE LEVEL CASCADED INVERTER", "venue": "", "year": 2013 }, { "abstract": "paper presents the comparison of Carrier Overlapping Pulse Width Modulation (COPWM) techniques for the Cascaded Multi Level Inverter (CMLI) A CMLI is controlled in this paper with Sinusoidal PWM (SPWM) reference, Third Harmonic Injection PWM (THI PWM) reference, Sixty degree PWM reference and Stepped wave reference with Carrier Overlapping (CO) techniques. The variation of Total Harmonic Distortion (THD) in the inverter output voltage is observed when the chosen inverter is controlled by SPWM for various modulation indices. Simulation is performed using MATLAB SIMULINK. It is observed that COPWM C provides output with relatively low distortion for all strategies. It is also seen that COPWM A is found to perform better for all strategies since it provides relatively higher fundamental RMS output voltage and in particular highest output is obtained for 60 degree PWM reference. KeywordsCMLI, Stepped, THIPWM, 60 degree PWM, COPWM.", "author_names": [ "Chinnapettai Ramalingam Balamurugan", "Sirukarumbur Pandurangan Natarajan", "R Bensraj" ], "corpus_id": 14844489, "doc_id": "14844489", "n_citations": 4, "n_key_citations": 2, "score": 0, "title": "Comparative Study on Carrier Overlapping PWM Strategies for Three Phase Five Level Cascaded Inverter", "venue": "", "year": 2012 }, { "abstract": "The hysteresis current controller provides excellent dynamic performance, whereas the Proportional Integral controller provides instantaneous current control and wave shaping, fixed inverter switching frequency resulting in only known harmonics. A comparative study between Hysteresis current control and Proportional Integral (PI) current control using sinusoidal pulse width modulation (SPWM) techniques for a five level cascaded H bridge multilevel inverter is presented in this paper. A comparison has been made in terms of total harmonic distortion (THD) level at the three phase load current. The simulation study has been carried out with the help of MATLAB Simulink software and the performance of such controllers has been observed during load variations.", "author_names": [ "K Sundararajan", "Alamelu Nachiappan" ], "corpus_id": 2599099, "doc_id": "2599099", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Comparison of Current Controllers for a Five level Cascaded H Bridge Multilevel Inverter", "venue": "", "year": 2012 }, { "abstract": "This paper presents the comparison of Carrier Overlapping Pulse Width Modulation (COPWM) techniques for the Cascaded Multi Level Inverter (CMLI) A CMLI is controlled in this paper with Sinusoidal PWM (SPWM) reference, Third Harmonic Injection PWM (THI PWM) reference, Sixty degree PWM reference and Stepped wave reference with Carrier Overlapping (CO) techniques. The variation of Total Harmonic Distortion (THD) in the inverter output voltage is observed when the chosen inverter is controlled by SPWM for various modulation indices. Simulation is performed using MATLAB SIMULINK. It is observed that COPWM C provides output with relatively low distortion for all strategies. It is also seen that COPWM A is found to perform better for all strategies since it provides relatively higher fundamental RMS output voltage and in particular highest output is obtained for 60 degree PWM reference.", "author_names": [ "Ivo Barbi", "Y Srinivasa Kishore Babu", "L Navinkumar Rao" ], "corpus_id": 12388235, "doc_id": "12388235", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Comparative Study on Carrier Overlapping PWM Strategies for Three Phase Five Level Cascaded Inverter", "venue": "", "year": 2012 }, { "abstract": "This work presents the comparison of various multicarrier based Pulse Width Modulation (PWM) techniques for the chosen Hbridge type Flying Capacitor Multi Level Inverter (FCMLI) In this paper, a H bridge type FCMLI is controlled with Sinusoidal PWM (SPWM) technique with Phase Disposition (PD) Phase Opposition and Disposition (POD) Alternative Opposition and Disposition (APOD) Carrier Overlapping (CO) Phase Shift (PS) and Variable Frequency (VF) PWM techniques and the variation of Total Harmonic Distortion (THD) in the output is observed by varying the modulation index. Simulation is performed using MATLAB SIMULINK. It is observed that sinusoidal reference with PSPWM provides output with relatively low distortion and relatively lower stress on the devices. It is also seen that COPWM strategy is found to perform better since it provides relatively higher fundamental RMS output voltage and relatively lower stress on the devices.", "author_names": [ "Chinnapettai Ramalingam Balamurugan", "Sirukarumbur Pandurangan Natarajan", "R Bensraj" ], "corpus_id": 59473366, "doc_id": "59473366", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Investigations on Three Phase Five Level Cascaded type FCMLI", "venue": "", "year": 2012 }, { "abstract": "This work proposes a comparison study of cascaded H bridge multilevel inverter (CHBMLI) in which symmetrical and asymmetrical arrangement of five level and seven level H bridge inverters are compared in order to find an optimized output voltage quality with lower harmonic distortion. Several studies have been conducted on the three phase cascaded symmetrical multilevel inverter (MLI).However, there are few studies that actually discuss or evaluate the performance of three phase H bridge asymmetrical MLI. Here, three multicarrier pulse width modulation (PWM) techniques such as constant switching frequency, variable switching frequency and phase shifted PWM are proposed. MATLAB/SIMULINK software is used for simulation. The carried out simulation studies shows that an asymmetrical configuration provides high output voltage with very low total harmonic distortion (THD) using less switching devices.", "author_names": [ "Venkatasubramaniam Bhuvaneswari", "Mayuri Harikumar", "A ShakilAhmed", "R Vinoth", "Ajith B Singh" ], "corpus_id": 212513279, "doc_id": "212513279", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Multicarrier Sinusoidal PWM Technique Based Analysis of Asymmetrical and Symmetrical 3F Cascaded MLI", "venue": "", "year": 2014 }, { "abstract": "This paper presents the comparative study of three phase twenty five level diode clamped and cascaded H bridge multilevel inverters. The comparison is made in respect of requirement of devices, quality of output voltage and reduction of total harmonic distortion at the multilevel inverter terminals. In this work multicarrier sinusoidal pulse modulation control methods of Phase disposition (PD PWM) phase opposition disposition (PODPWM) and Alternative Phase Opposition Disposition (APOD PWM) pulse width modulation control strategies are applied for both diode clamped and cascaded H bridge multilevel inverters and compared its total harmonic distortion. The performance of both diode and cascaded H bridge multilevel inverters is investigated and compared. Based on simulation results it is observed that the output voltage of the cascaded H bridge multilevel inverters is better as compared to the diode clamped multilevel inverter. The proposed multilevel inverters are simulated using MATLAB/Simulink software.", "author_names": [ "Sangeetha Sadu", "P Venkata Vara Prasad", "G N Srinivas" ], "corpus_id": 55077757, "doc_id": "55077757", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Simulation and Comparison of Twenty Five Level Diode Clamped Cascaded H Bridge Multilevel Inverter", "venue": "", "year": 2018 } ]

[ { "abstract": "Semiconductor etching can now be monitored in real time at nanoscale resolution using a non destructive optical imaging technique that combines a conventional microscope with a compact Mach Zehnder interferometer. Developed by Chris Edwards, Amir Arbabi, Gabriel Popescu, and Lynford Goddard at the University of Illinois at Urbana Champaign in the United States, epi diffraction phase microscopy makes it possible to collect three dimensional videos of semiconductor fabrication processes using a CCD camera. The approach is able to measure etch rates at each location across the sample with a resolution of 0.085 nm s 1 per pixel. Such an in situ monitoring capability could be useful for improving the manufacturing quality of a wide variety of semiconductor devices.", "author_names": [ "Chris Edwards", "Amir Arbabi", "Gabriel Popescu", "Lynford L Goddard" ], "corpus_id": 53665642, "doc_id": "53665642", "n_citations": 102, "n_key_citations": 2, "score": 1, "title": "Optically monitoring and controlling nanoscale topography during semiconductor etching", "venue": "", "year": 2012 }, { "abstract": "", "author_names": [ "Christopher J Edwards", "Amir Arbabi", "Gabriel Popescu", "Lynford L Goddard" ], "corpus_id": 125760636, "doc_id": "125760636", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Erratum: Optically monitoring and controlling nanoscale topography during semiconductor etching (Light: Science Applications (2012) 1(e30) doi:10.1038/lsa.2012.30)", "venue": "", "year": 2012 }, { "abstract": "Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The promise of improved thermoelectric materials and problems of thermal management of optoelectronic devices have stimulated extensive studies of semiconductor superlattices; agreement between experiment and theory is generally poor. Advances in measurement methods, e.g. the 3o method, time domain thermoreflectance, sources of coherent phonons, microfabricated test structures, and the scanning thermal microscope, are enabling new capabilities for nanoscale thermal metrology.", "author_names": [ "David G Cahill", "W Ford", "Kenneth E Goodson", "Gerald Dennis Mahan", "A Majumdar", "Humphrey J Maris", "Roberto Merlin", "Simon R Phillpot" ], "corpus_id": 15327316, "doc_id": "15327316", "n_citations": 2460, "n_key_citations": 42, "score": 0, "title": "Nanoscale thermal transport", "venue": "", "year": 2003 }, { "abstract": "Preface to Third Edition. 1 Resistivity. 1.1 Introduction. 1.2 Two Point Versus Four Point Probe. 1.3 Wafer Mapping. 1.4 Resistivity Profiling. 1.5 Contactless Methods. 1.6 Conductivity Type. 1.7 Strengths and Weaknesses. Appendix 1.1 Resistivity as a Function of Doping Density. Appendix 1.2 Intrinsic Carrier Density. References. Problems. Review Questions. 2 Carrier and Doping Density. 2.1 Introduction. 2.2 Capacitance Voltage (C V) 2.3 Current Voltage (I V) 2.4 Measurement Errors and Precautions. 2.5 Hall Effect. 2.6 Optical Techniques. 2.7 Secondary Ion Mass Spectrometry (SIMS) 2.8 Rutherford Backscattering (RBS) 2.9 Lateral Profiling. 2.10 Strengths and Weaknesses. Appendix 2.1 Parallel or Series Connection? Appendix 2.2 Circuit Conversion. References. Problems. Review Questions. 3 Contact Resistance and Schottky Barriers. 3.1 Introduction. 3.2 Metal Semiconductor Contacts. 3.3 Contact Resistance. 3.4 Measurement Techniques. 3.5 Schottky Barrier Height. 3.6 Comparison of Methods. 3.7 Strengths and Weaknesses. Appendix 3.1 Effect of Parasitic Resistance. Appendix 3.2 Alloys for Contacts to Semiconductors. References. Problems. Review Questions. 4 Series Resistance, Channel Length and Width, and Threshold Voltage. 4.1 Introduction. 4.2 PN Junction Diodes. 4.3 Schottky Barrier Diodes. 4.4 Solar Cells. 4.5 Bipolar Junction Transistors. 4.6 MOSFETS. 4.7 MESFETS and MODFETS. 4.8 Threshold Voltage. 4.9 Pseudo MOSFET. 4.10 Strengths and Weaknesses. Appendix 4.1 Schottky Diode Current Voltage Equation. References. Problems. Review Questions. 5 Defects. 5.1 Introduction. 5.2 Generation Recombination Statistics. 5.3 Capacitance Measurements. 5.4 Current Measurements. 5.5 Charge Measurements. 5.6 Deep Level Transient Spectroscopy (DLTS) 5.7 Thermally Stimulated Capacitance and Current. 5.8 Positron Annihilation Spectroscopy (PAS) 5.9 Strengths and Weaknesses. Appendix 5.1 Activation Energy and Capture Cross Section. Appendix 5.2 Time Constant Extraction. Appendix 5.3 Si and GaAs Data. References. Problems. Review Questions. 6 Oxide and Interface Trapped Charges, Oxide Thickness. 6.1 Introduction. 6.2 Fixed, Oxide Trapped, and Mobile Oxide Charge. 6.3 Interface Trapped Charge. 6.4 Oxide Thickness. 6.5 Strengths and Weaknesses. Appendix 6.1 Capacitance Measurement Techniques. Appendix 6.2 Effect of Chuck Capacitance and Leakage Current. References. Problems. Review Questions. 7 Carrier Lifetimes. 7.1 Introduction. 7.2 Recombination Lifetime/Surface Recombination Velocity. 7.3 Generation Lifetime/Surface Generation Velocity. 7.4 Recombination Lifetime Optical Measurements. 7.5 Recombination Lifetime Electrical Measurements. 7.6 Generation Lifetime Electrical Measurements. 7.7 Strengths and Weaknesses. Appendix 7.1 Optical Excitation. Appendix 7.2 Electrical Excitation. References. Problems. Review Questions. 8 Mobility. 8.1 Introduction. 8.2 Conductivity Mobility. 8.3 Hall Effect and Mobility. 8.4 Magnetoresistance Mobility. 8.5 Time of Flight Drift Mobility. 8.6 MOSFET Mobility. 8.7 Contactless Mobility. 8.8 Strengths and Weaknesses. Appendix 8.1 Semiconductor Bulk Mobilities. Appendix 8.2 Semiconductor Surface Mobilities. Appendix 8.3 Effect of Channel Frequency Response. Appendix 8.4 Effect of Interface Trapped Charge. References. Problems. Review Questions. 9 Charge based and Probe Characterization. 9.1 Introduction. 9.2 Background. 9.3 Surface Charging. 9.4 The Kelvin Probe. 9.5 Applications. 9.6 Scanning Probe Microscopy (SPM) 9.7 Strengths and Weaknesses. References. Problems. Review Questions. 10 Optical Characterization. 10.1 Introduction. 10.2 Optical Microscopy. 10.3 Ellipsometry. 10.4 Transmission. 10.5 Reflection. 10.6 Light Scattering. 10.7 Modulation Spectroscopy. 10.8 Line Width. 10.9 Photoluminescence (PL) 10.10 Raman Spectroscopy. 10.11 Strengths and Weaknesses. Appendix 10.1 Transmission Equations. Appendix 10.2 Absorption Coefficients and Refractive Indices for Selected Semiconductors. References. Problems. Review Questions. 11 Chemical and Physical Characterization. 11.1 Introduction. 11.2 Electron Beam Techniques. 11.3 Ion Beam Techniques. 11.4 X Ray and Gamma Ray Techniques. 11.5 Strengths and Weaknesses. Appendix 11.1 Selected Features of Some Analytical Techniques. References. Problems. Review Questions. 12 Reliability and Failure Analysis. 12.1 Introduction. 12.2 Failure Times and Acceleration Factors. 12.3 Distribution Functions. 12.4 Reliability Concerns. 12.5 Failure Analysis Characterization Techniques. 12.6 Strengths and Weaknesses. Appendix 12.1 Gate Currents. References. Problems. Review Questions. Appendix 1 List of Symbols. Appendix 2 Abbreviations and Acronyms. Index.", "author_names": [ "Dieter K Schroder" ], "corpus_id": 110493874, "doc_id": "110493874", "n_citations": 6120, "n_key_citations": 383, "score": 0, "title": "Semiconductor Material and Device Characterization", "venue": "", "year": 1990 }, { "abstract": "A formation process for semiconductor quantum dots based on a surface instability induced by ion sputtering under normal incidence is presented. Crystalline dots 35 nanometers in diameter and arranged in a regular hexagonal lattice were produced on gallium antimonide surfaces. The formation mechanism relies on a natural self organization mechanism that occurs during the erosion of surfaces, which is based on the interplay between roughening induced by ion sputtering and smoothing due to surface diffusion.", "author_names": [ "" ], "corpus_id": 14886850, "doc_id": "14886850", "n_citations": 649, "n_key_citations": 4, "score": 0, "title": "Formation of Ordered Nanoscale Semiconductor Dots by Ion Sputtering.", "venue": "Science", "year": 1999 }, { "abstract": "This protocol provides an introduction to soft lithography a collection of techniques based on printing, molding and embossing with an elastomeric stamp. Soft lithography provides access to three dimensional and curved structures, tolerates a wide variety of materials, generates well defined and controllable surface chemistries, and is generally compatible with biological applications. It is also low in cost, experimentally convenient and has emerged as a technology useful for a number of applications that include cell biology, microfluidics, lab on a chip, microelectromechanical systems and flexible electronics/photonics. As examples, here we focus on three of the commonly used soft lithographic techniques: (i) microcontact printing of alkanethiols and proteins on gold coated and glass substrates; (ii) replica molding for fabrication of microfluidic devices in poly(dimethyl siloxane) and of nanostructures in polyurethane or epoxy; and (iii) solvent assisted micromolding of nanostructures in poly(methyl methacrylate)", "author_names": [ "Dong Qin", "Younan Xia", "George M Whitesides" ], "corpus_id": 3355464, "doc_id": "3355464", "n_citations": 1530, "n_key_citations": 22, "score": 0, "title": "Soft lithography for micro and nanoscale patterning", "venue": "Nature Protocols", "year": 2010 }, { "abstract": "An aluminum coated tapered optical fiber is rigidly attached to one of the prongs of a high Q piezoelectric tuning fork. The fork is mechanically dithered at its resonance frequency (33 kHz) so that the tip amplitude does not exceed 0.4 nm. A corresponding piezoelectric signal is measured on electrodes appropriately placed on the prongs. As the tip approaches within 20 nm above the sample surface a 0.1 nN drag force acting on the tip causes the signal to reduce. This signal is used to position the optical fiber tip to about 0 to 25 nm above the sample. Shear forces resulting from the tip sample interaction can be quantitatively deduced.", "author_names": [ "Khaled Karrai", "Robert D Grober" ], "corpus_id": 123268538, "doc_id": "123268538", "n_citations": 877, "n_key_citations": 13, "score": 0, "title": "Piezoelectric tip sample distance control for near field optical microscopes", "venue": "", "year": 1995 }, { "abstract": "Over the last 2 decades, scanning electrochemical microscopy (SECM) has been extensively employed for topographic imaging and mapping surface reactivity on the micrometer scale. We used flat, polished nanoelectrodes as SECM tips to carry out feedback mode imaging of various substrates with nanoscale resolution. Constant height and constant current images of plastic and Au compact disc surfaces and more complicated objects (computer chips and wafers) were obtained. The possibility of simultaneous imaging of surface topography and electrochemical reactivity was demonstrated. Very fast mass transfer at nanoelectrodes allowed us to obtain high quality electrochemical images in viscous media under steady state conditions, e.g. in 1 methyl 3 octylimidazolium bis(tetrafluoromethylsulfonyl)imide (C(8)mimC(1)C(1)N) ionic liquid. Ion transfer based imaging was also performed using nanopipets as SECM tips.", "author_names": [ "Francois O Laforge", "Jeyavel Velmurugan", "Yixian Wang", "Michael V Mirkin" ], "corpus_id": 8035845, "doc_id": "8035845", "n_citations": 80, "n_key_citations": 0, "score": 0, "title": "Nanoscale imaging of surface topography and reactivity with the scanning electrochemical microscope.", "venue": "Analytical chemistry", "year": 2009 }, { "abstract": "As multistep, multilayer processing in semiconductor industry becomes more complex, the role of cleaning solutions and etching chemistries are becoming important in enhancing yield and in reducing defects. This thesis demonstrates successful formulations that exhibit copper and tungsten compatibility, and are capable of Inter Layer Dielectric (ILD) cleaning and selective Ti etching. The corrosion behavior of electrochemically deposited copper thin films in deareated and non dearated cleaning solution containing hydrofluoric acid (HF) has been investigated. Potentiodynamic polarization experiments were carried out to determine active, active passive, passive, and transpassive regions. Corrosion rates were calculated from tafel slopes. ICP MS and potentiodynamic methods yielded comparable Cu dissolution rates. Interestingly, the presence of hydrogen peroxide in the cleaning solution led to more than an order of magnitude suppression of copper dissolution rate. We ascribe this phenomenon to the formation of interfacial CuO which dissolves at slower rate in dilute HF. A kinetic scheme involving cathodic reduction of oxygen and anodic oxidation of Cu0 and Cu+1 is proposed. It was determined that the reaction order kinetics is first order with respect to both HF and oxygen concentrations. The learnings from copper corrosion studies were leveraged to develop a wet etch/clean formulation for selective titanium etching. The introduction of titanium hard mask (HM) for dual damascene patterning of copper interconnects created a unique application in selective wet etch chemistry. A formulation that addresses the selectivity requirements was not available and was developed during the course of this dissertation. This chemical formulation selectively strips Ti HM film and removes post plasma etch polymer/residue while suppressing the etch rate of tungsten, copper, silicon oxide, silicon carbide, silicon nitride, and carbon doped silicon oxide. Ti etching selectivity exceeding three orders of magnitude was realized. Surprisingly, it exploits the use of HF, a chemical well known for its SiO2 etching ability, along with a silicon precursor to protect SiO2. The ability to selectively etch the Ti HM without impacting key transistor/interconnect components has enabled advanced process technology nodes of today and beyond. This environmentally friendly formulation is now employed in production of advanced high performance microprocessors and produced in a 3000 gallon reactor.", "author_names": [ "Nabil George Mistkawi" ], "corpus_id": 92048486, "doc_id": "92048486", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Fundamental Studies in Selective Wet Etching and Corrosion Processes for High Performance Semiconductor Devices", "venue": "", "year": 2010 }, { "abstract": "Specular mode spectroscopic ellipsometry (SE) or reflectometry (SR) from periodic gratings have been successfully demonstrated as accurate methods for extracting detailed topography of integrated circuit structures. However, as critical dimensions become very much less than the current minimum measurement wavelengths and as film thicknesses are simultaneously reduced, there are significant questions regarding the long term usefulness of this method. In this paper, I will attempt to address some major aspects of this problem.", "author_names": [ "Fred Lewis Terry" ], "corpus_id": 109501016, "doc_id": "109501016", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Accuracy limitations in specular mode optical topography extraction", "venue": "SPIE Advanced Lithography", "year": 2003 } ]

[ { "abstract": "SUMMARY This paper reviews recent important results in the development of neuromorphic network architectures 'CrossNets' for future hybrid semiconductor=nanodevice integrated circuits. In particular, we have shown that despite the hardware imposed limitations, a simple weight import procedure allows the CrossNets using simple two terminal nanodevices to perform functions (such as image recognition and pattern classication) that had been earlier demonstrated in neural networks with continuous, determin istic synaptic weights. Moreover, CrossNets can also be trained to work as classiers by the faster error backpropagation method, despite the absence of a layered structure typical for the usual neural networks. Finally, one more method, 'global reinforcement' may be suitable for training CrossNets to perform not only the pattern classication, but also more intellectual tasks. A demonstration of such training would open a way towards articial cerebral cortex scale networks capable of advanced infor mation processing (and possibly self development) at a speed several orders of magnitude higher than that of their biological prototypes. Copyright 2004 John Wiley Sons, Ltd.", "author_names": [ "Ozgur Turel", "Jung Hoon Lee", "Xiaolong Ma", "Konstantin K Likharev" ], "corpus_id": 15815752, "doc_id": "15815752", "n_citations": 120, "n_key_citations": 15, "score": 1, "title": "Neuromorphic architectures for nanoelectronic circuits", "venue": "Int. J. Circuit Theory Appl.", "year": 2004 }, { "abstract": "This paper reviews recent important results in the development of neuromorphic network architectures 'CrossNets' for future hybrid semiconductor/nanodevice integrated circuits. In particular, we have shown that despite the hardware imposed limitations, a simple weight import procedure allows the CrossNets using simple two terminal nanodevices to perform functions (such as image recognition and pattern classification) that had been earlier demonstrated in neural networks with continuous, deterministic synaptic weights. Moreover, CrossNets can also be trained to work as classifiers by the faster error backpropagation method, despite the absence of a layered structure typical for the usual neural networks. Finally, one more method, 'global reinforcement' may be suitable for training CrossNets to perform not only the pattern classification, but also more intellectual tasks. A demonstration of such training would open a way towards artificial cerebral cortex scale networks capable of advanced information processing (and possibly self development) at a speed several orders of magnitude higher than that of their biological prototypes. Copyright (c) 2004 John Wiley Sons, Ltd.", "author_names": [ "Ozgur Turel", "Jung Hoon Lee", "Xiaolong Ma", "Konstantin K Likharev" ], "corpus_id": 116751512, "doc_id": "116751512", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Neuromorphic architectures for nanoelectronic circuits: Research Articles", "venue": "", "year": 2004 }, { "abstract": "Memristive and nanoionic devices have recently emerged as leading candidates for neuromorphic computing architectures. While top down fabrication based on conventional bulk materials has enabled many early neuromorphic devices and circuits, bottom up approaches based on low dimensional nanomaterials have shown novel device functionality that often better mimics a biological neuron. In addition, the chemical, structural and compositional tunability of low dimensional nanomaterials coupled with the permutational flexibility enabled by van der Waals heterostructures offers significant opportunities for artificial neural networks. In this Review, we present a critical survey of emerging neuromorphic devices and architectures enabled by quantum dots, metal nanoparticles, polymers, nanotubes, nanowires, two dimensional layered materials and van der Waals heterojunctions with a particular emphasis on bio inspired device responses that are uniquely enabled by low dimensional topology, quantum confinement and interfaces. We also provide a forward looking perspective on the opportunities and challenges of neuromorphic nanoelectronic materials in comparison with more mature technologies based on traditional bulk electronic materials. This Review highlights the progress made towards the development of neuromorphic devices and architectures enabled by low dimensional nanomaterials", "author_names": [ "Vinod K Sangwan", "Mark C Hersam" ], "corpus_id": 211729789, "doc_id": "211729789", "n_citations": 103, "n_key_citations": 0, "score": 0, "title": "Neuromorphic nanoelectronic materials", "venue": "Nature Nanotechnology", "year": 2020 }, { "abstract": "Hybrid \"CMOL\" integrated circuits, combining CMOS subsystem with nanowire crossbars and simple two terminal nanodevices, promise to extend the exponential Moore Law development of microelectronics into the sub 10 nm range. We are developing neuromorphic network \"CrossNet\" architectures for this future technology, in which neural cell bodies are implemented in CMOS, nanowires are used as axons and dendrites, while nanodevices (bistable latching switches) are used as elementary synapses. We have shown how CrossNets may be trained to perform pattern recovery and classification despite the limitations imposed by the CMOL hardware. Preliminary estimates have shown that CMOL CrossNets may be extremely dense ~107 cells per cm2) and operate approximately a million times faster than biological neural networks, at manageable power consumption. In Conclusion, we discuss in brief possible short term and long term applications of the emerging technology.", "author_names": [ "Jung Hoon Lee", "Xiaolong Ma", "Konstantin K Likharev" ], "corpus_id": 15108825, "doc_id": "15108825", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "CMOL CrossNets: Possible Neuromorphic Nanoelectronic Circuits", "venue": "NIPS", "year": 2005 }, { "abstract": "This is a concise review of the recent work on devices, circuits and architectures for possible hybrid semiconductor/nanodevice integrated circuits based on nanowire crossbars, with similar, simple, two terminal devices formed at each crosspoint. Special attention is given to the so called \"CMOL' variety of the hybrids, in which the crossbar is connected to the underlying CMOS circuit, using an area distributed, pin based interface. Recent detailed studies have shown that digital hybrid circuits may extend the Moore's Law progress of integrated circuits for 10 to 15 years. Even more impressive, mixed signal neuromorphic networks \"CrossNets\" may provide unparalleled performance for some important information processing tasks, and in future may become the first hardware basis for challenging the mammal cerebral cortex in density, far exceeding it in speed, at manageable power consumption. Recently, the hybrid circuit concept received a strong boost from the experimental demonstrations of reproducible crosspoint devices (latching switches) based on amorphous silicon and metal oxides, and of nanowire crossbars with 15 nm scale half pitch. However, CMOL technology still faces several significant challenges, briefly discussed in the last section.", "author_names": [ "Konstantin K Likharev" ], "corpus_id": 100842614, "doc_id": "100842614", "n_citations": 120, "n_key_citations": 4, "score": 0, "title": "Hybrid CMOS/Nanoelectronic Circuits: Opportunities and Challenges", "venue": "", "year": 2008 }, { "abstract": "Hybrid \"CMOL\" integrated circuits, incorporating advanced CMOS devices for neural cell bodies, nanowires as axons and dendrites, and single molecule latching switches as synapses, may be used for the hardware implementation of extremely dense ~107 cells and ~1012 synapses per cm2) neuromorphic networks, operating up to 106 times faster than their biological prototypes. We are exploring several \"CrossNet\" architectures that accommodate the limitations imposed by CMOL hardware and should allow effective training of the networks without a direct external access to individual synapses. CrossNet training in the Hopfield mode have been confirmed on a software model of the network.", "author_names": [ "Ozgur Turel", "Konstantin K Likharev" ], "corpus_id": 5416346, "doc_id": "5416346", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "CrossNets: Neuromorphic Networks for Nanoelectronic Implementation", "venue": "ICANN", "year": 2003 }, { "abstract": "Our group is developing neuromorphic network architectures for future hybrid semiconductor/nanowire/molecular \"CMOL\" circuits. Estimates show that such networks \"CrossNets\" may eventually overcome the cerebral cortex in areal density, operating at much higher speed, at acceptable power consumption. In this report, we demonstrate that CrossNets based on simple (two terminal) molecular devices can be configured to reproduce the behavior of any known neural network, either feedforward or recurrent, using a synaptic weight import procedure. Two other training methods including the global reinforcement (that may enable CrossNets to perform more intelligent tasks) are also described in brief.", "author_names": [ "Ozgur Turel", "Jung Hoon Lee", "Xiaolong Ma", "Konstantin K Likharev" ], "corpus_id": 18659237, "doc_id": "18659237", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Nanoelectronic neuromorphic networks (CrossNets) new results", "venue": "2004 IEEE International Joint Conference on Neural Networks (IEEE Cat. No.04CH37541)", "year": 2004 }, { "abstract": "Memristors are novel non volatile devices that manage to combine storing and processing capabilities in the same physical place. Their nanoscale dimensions and low power consumption enable the further design of various nanoelectronic processing circuits and corresponding computing architectures, like neuromorphic, in memory, unconventional, etc. One of the possible ways to exploit the memristor's advantages is by combining them with Cellular Automata (CA) CA constitute a well known non von Neumann computing architecture that is based on the local interconnection of simple identical cells forming N dimensional grids. These local interconnections allow the emergence of global and complex phenomena. In this paper, we propose a hybridization of the CA original definition coupled with memristor based implementation, and, more specifically, we focus on Memristive Learning Cellular Automata (MLCA) which have the ability of learning using also simple identical interconnected cells and taking advantage of the memristor devices inherent variability. The proposed MLCA circuit level implementation is applied on optimal detection of edges in image processing through a series of SPICE simulations, proving its robustness and efficacy.", "author_names": [ "Rafailia-Eleni Karamani", "Iosif-Angelos Fyrigos", "Vasileios G Ntinas", "Orestis Liolis", "Giorgos Dimitrakopoulos", "Mustafa Altun", "Andrew Adamatzky", "Mircea R Stan", "Georgios Ch Sirakoulis" ], "corpus_id": 212725049, "doc_id": "212725049", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Memristive Learning Cellular Automata: Theory and Applications", "venue": "2020 9th International Conference on Modern Circuits and Systems Technologies (MOCAST)", "year": 2020 }, { "abstract": "Non Boolean computing based on emerging postCMOS technologies can potentially pave the way for low power neural computing platforms. However, existing work on such emerging neuromorphic architectures have either focused on solely mimicking the neuron, or the synapse functionality. While memristive devices have been proposed to emulate biological synapses, spintronic devices have proved to be efficient at performing the thresholding operation of the neuron at ultra low currents. In this work, we propose an All Spin Artificial Neural Network where a single spintronic device acts as the basic building block of the system. The device offers a direct mapping to synapse and neuron functionalities in the brain while inter layer network communication is accomplished via CMOS transistors. To the best of our knowledge, this is the first demonstration of a neural architecture where a single nanoelectronic device is able to mimic both neurons and synapses. The ultra low voltage operation of low resistance magneto metallic neurons enables the low voltage operation of the array of spintronic synapses, thereby leading to ultra low power neural architectures. Device level simulations, calibrated to experimental results, was used to drive the circuit and system level simulations of the neural network for a standard pattern recognition problem. Simulation studies indicate energy savings by ~400x in comparison to a corresponding digital/ analog CMOS neuron implementation.", "author_names": [ "Abhronil Sengupta", "Yong Shim", "Kaushik Roy" ], "corpus_id": 14284227, "doc_id": "14284227", "n_citations": 113, "n_key_citations": 10, "score": 0, "title": "Proposal for an All Spin Artificial Neural Network: Emulating Neural and Synaptic Functionalities Through Domain Wall Motion in Ferromagnets", "venue": "IEEE Transactions on Biomedical Circuits and Systems", "year": 2016 }, { "abstract": "Since CMOS technology approaches its physical limits, the spotlight of computing technologies and architectures shifts to unconventional computing approaches. In this area, novel computing systems, inspired by natural and mostly nonelectronic approaches, provide also new ways of performing a wide range of computations, from simple logic gates to solving computationally hard problems. Reaction diffusion processes constitute an information processing method, occurs in nature and are capable of massive parallel and low power computing, such as chemical computing through Belousov Zhabotinsky reaction. In this paper, inspired by these chemical processes and based on the wave propagation information processing taking place in the reaction diffusion media, the novel characteristics of the nanoelectronic element memristor are utilized to design innovative circuits of electronic excitable medium to perform both classical (Boolean) calculations and to model neuromorphic computations in the same Memristor RLC (M RLC) reconfigurable network.", "author_names": [ "Iosif-Angelos Fyrigos", "Vasileios G Ntinas", "Georgios Ch Sirakoulis", "Andrew Adamatzky", "Victor V Erokhin", "Antonio Rubio" ], "corpus_id": 155693259, "doc_id": "155693259", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Wave Computing with Passive Memristive Networks", "venue": "2019 IEEE International Symposium on Circuits and Systems (ISCAS)", "year": 2019 } ]

[ { "abstract": "The classical hydrodynamic equations can be extended to include quantum effects by incorporating the first quantum corrections. These quantum corrections are $O( \\hbar ^2 The full three dimensional quantum hydrodynamic (QHD) model is derived for the first time by a moment expansion of the Wigner Boltzmann equation. The QHD conservation laws have the same form as the classical hydrodynamic equations, but the energy density and stress tensor have additional quantum terms. These quantum terms allow particles to tunnel through potential barriers and to build up in potential wells.The three dimensional QHD transport equations are mathematically classified as having two Schrodinger modes, two hyperbolic modes, and one parabolic mode. The one dimensional steady state QHD equations are discretized in conservation form using the second upwind method.Simulations of a resonant tunneling diode are presented that show charge buildup in the quantum well and negative differential resistance (NDR) in the current v.", "author_names": [ "Carl L Gardner" ], "corpus_id": 35294903, "doc_id": "35294903", "n_citations": 487, "n_key_citations": 26, "score": 1, "title": "The Quantum Hydrodynamic Model for Semiconductor Devices", "venue": "SIAM J. Appl. Math.", "year": 1994 }, { "abstract": "A \"smooth\" quantum hydrodynamic (QHD) model for semiconductor devices is derived by a Chapman Enskog expansion of the Wigner Boltzmann equation which can handle in a mathematically rigorous way the discontinuities in the classical potential energy which occur at heterojunction barriers in quantum semiconductor devices. A dispersive quantum contribution to the heat flux term in the QHD model is introduced.", "author_names": [ "Carl L Gardner", "Christian A Ringhofer" ], "corpus_id": 51957447, "doc_id": "51957447", "n_citations": 48, "n_key_citations": 4, "score": 0, "title": "The Chapman Enskog Expansion and the Quantum Hydrodynamic Model for Semiconductor Devices", "venue": "VLSI Design", "year": 2000 }, { "abstract": "Abstract A finite element method for numerical simulation of the transient quantum hydrodynamic model for semiconductor devices is presented. This model treats electron flow in a semiconductor device in the same manner as the classical hydrodynamic model, but the energy density and stress tensor include additional quantum terms, which allow particles to tunnel through potential barriers and to build up in potential wells. The finite element method under consideration is based on use of a mixed method for the approximation of the electric field and a shock capturing Runge Kutta discontinuous Galerkin method for the quantum hydrodynamic conservation laws. Numerical simulations of a resonant tunneling diode are presented, which show charge buildup in the quantum well and negative differential resistance and a hysteresis in the current voltage curve. A comparison between the present method and a finite difference method is given.", "author_names": [ "Zhangxin Chen" ], "corpus_id": 120302867, "doc_id": "120302867", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "A finite element method for the quantum hydrodynamic model for semiconductor devices", "venue": "", "year": 1996 }, { "abstract": "Abstract In this article, fifth order finite volume multi resolution weighted essentially non oscillatory (MR WENO) scheme is developed for solving one dimensional non linear viscous quantum hydrodynamical model for semiconductor devices with constant temperature. This non linear model consists of three equations, two equations for the current density and electron density, and third equation is the Poisson equation. The first two equations include the viscous and quantum correction terms. Further, numerical technique is used to obtain the solution due to high non linearity of considered model. The multi resolution technique is used to reduce the computational cost of high resolution numerical scheme. In the procedure of derivation of the MR WENO scheme unequal central spatial stencils are used and linear weights can be chosen any positive numbers with only restriction that their total sum is one. Various numerical test problems are considered to check the validity and accuracy of the derived numerical scheme. Further, the results obtained from considered numerical scheme are compared with those of kinetic flux vector splitting numerical scheme.", "author_names": [ "Tauqeer Ahmed", "Asad Rehman", "Ashiq Ali", "Shamsul Qamar" ], "corpus_id": 233594471, "doc_id": "233594471", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A high order multi resolution WENO numerical scheme for solving viscous quantum hydrodynamic model for semiconductor devices", "venue": "", "year": 2021 }, { "abstract": "Abstract Quantum transport effects including electron or hole tunneling through potential barriers and buildup in quantum wells are important in predicting the performance of ultra small semiconductor devices. These effects can be incorporated into the hydrodynamic description of charge propagation in the semiconductor device. A new extension of the classical hydrodynamic model to include quantum transport effects was derived. This \"smooth\" quantum hydrodynamic (QHD) model is derived specifically to handle in a mathematically rigorous way the discontinuities in the classical potential energy which occur at heterojunction barriers in quantum semiconductor devices. The smooth QHD model makes the barriers partially transparent to the particle flow and provides the mechanism for particle tunneling in the QHD model. Smooth quantum hydrodynamic model simulations of the resonant tunneling diode were presented which exhibit enhanced negative differential resistance (NDR) when compared to simulations using the original QHD model. At both 300 K and 77 K, the smooth QHD simulations predict significant NDR even when the original QHD model simulations predict no NDR.", "author_names": [ "Carl L Gardner" ], "corpus_id": 115951417, "doc_id": "115951417", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "The Quantum Hydrodynamic Model for Semiconductor Devices: Theory and Computations", "venue": "", "year": 1998 }, { "abstract": "Abstract An extension of the classical hydrodynamic model for semiconductor devices to include quantum transport effects is reviewed. This \"smooth\" quantum hydrodynamic (QHD) model is derived specifically to handle in a mathematically rigorous way the discontinuities in the classical potential energy which occur at heterojunction barriers in quantum semiconductor devices. A conservative upwind discretization of the one dimensional (1D) steady state smooth QHD equations is outlined. Smooth QHD model simulations of the resonant tunneling diode are presented which exhibit enhanced negative differential resistance when compared with simulations using the original O( 2 QHD model.", "author_names": [ "Carl L Gardner", "Christian A Ringhofer" ], "corpus_id": 15698139, "doc_id": "15698139", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Numerical simulation of the smooth quantum hydrodynamic model for semiconductor devices", "venue": "", "year": 2000 }, { "abstract": "Abstract The \"smooth\" quantum hydrodynamic (QHD) model is an extension of the classical hydrodynamic model for semiconductor devices which can handle in a mathematically rigorous way the discontinuities in the classical potential energy which occur at heterojunction barriers in quantum semiconductor devices. Smooth QHD model simulations of the resonant tunneling diode exhibit negative differential resistance the experimental signal for quantum resonance effects. Resonant tunneling is analyzed in fluid dynamical terms from the point of view of the smooth QHD transport equations.", "author_names": [ "Carl L Gardner", "Christain Ringhofer" ], "corpus_id": 120583962, "doc_id": "120583962", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Resonant tunneling in the smooth quantum hydrodynamic model for semiconductor devices", "venue": "", "year": 2000 }, { "abstract": "Abstract We study a hybrid model linking the quantum hydrodynamics equation with classical hydrodynamics deriving the transmission conditions between the two PDE systems modeling the quantum and the classical dynamics. These conditions are derived under the assumption of constant scaled temperature and assuming a current jump across the interface between the classical and the quantum region. In Section 2.2 we shall give a heuristic and physically plausible explanation of this assumption. Because of this fact we produce not a weak solution on the whole device domain, but a piecewise smooth solution.", "author_names": [ "Federica Di Michele", "Pierangelo Marcati", "Bruno Rubino" ], "corpus_id": 121085901, "doc_id": "121085901", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Steady states and interface transmission conditions for heterogeneous quantum classical 1 D hydrodynamic model of semiconductor devices", "venue": "", "year": 2013 }, { "abstract": "Abstract In this article, one dimensional viscous quantum hydrodynamical model of semiconductor devices is numerically investigated. The model treats the propagation of electrons in a semiconductor device as the flow of a charged compressible fluid. It plays an important role in predicting the behavior of electron flow in semiconductor devices. The nonlinear viscous quantum hydrodynamic models contain Euler type equations for density and current, viscous and quantum correction terms, and a Poisson equation for electrostatic potential. Due to high nonlinearity of model equations, numerical solution techniques are applied to obtain their solutions. The proposed numerical scheme is a splitting scheme based on the kinetic flux vector splitting (KFVS) method for the hyperbolic step, and a semi implicit Runge Kutta method for the relaxation step. The KFVS method is based on the direct splitting of macroscopic flux functions of the system on the cell interfaces. The second order accuracy of the scheme is achieved by using MUSCL type initial reconstruction and Runge Kutta time stepping method. Several case studies are considered. For validation, the results of current scheme are compared with those obtained from the splitting scheme based on the NT central scheme. The effects of various parameters such as device length, viscosities, different doping and voltage are analyzed. The accuracy, efficiency and simplicity of the proposed KFVS scheme validates its generic applicability to the given model equations.", "author_names": [ "Ubaid Ahmed Nisar", "Waqas Ashraf", "Shamsul Qamar" ], "corpus_id": 55275347, "doc_id": "55275347", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Application of kinetic flux vector splitting scheme for solving viscous quantum hydrodynamical model of semiconductor devices", "venue": "", "year": 2018 }, { "abstract": "In this article, one dimensional viscous quantum hydro dynamical model of semiconductor devices is numerically investigated. The model treats the propagation of electrons in a semiconductor device as the flow of a charged compressible fluid. It plays an important role in predicting the behaviour of electron flow in semiconductor devices. The nonlinear viscous quantum hydrodynamic models contain Euler type equations for density and current, viscous and quantum correction terms, and a Poisson equation for electrostatic potential. Due to high nonlinearity of model equations, numerical solution techniques are applied to obtain their solutions. The proposed numerical scheme is a splitting scheme based on the kinetic flux vector splitting (KFVS) method for the hyperbolic step, and a semi implicit Runge Kutta method for the relaxation step. The KFVS method is based on the direct splitting of macroscopic flux functions of the system on the cell interfaces. The second order accuracy of the scheme is achieved by using MUSCL type initial reconstruction and Runge Kutta time stepping method. Several case studies are considered. For validation, the results of current scheme are compared with those obtained from the splitting scheme based on the NT central scheme. The effects of various parameters such as device length, viscosities, different doping and voltage are analyzed. The accuracy, efficiency and simplicity of the proposed KFVS scheme validates its generic applicability to the given model equation", "author_names": [ "Waqas Ashrafb", "Shamsul Qamarc", "Ubaid Ahmed Nisara" ], "corpus_id": 126260029, "doc_id": "126260029", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Application of Kinetic Flux Vector Splitting Scheme for Solving Viscous Quantum Hydrodynamical Model of Semiconductor Devices", "venue": "", "year": 2018 } ]

[ { "abstract": "We demonstrated coherent control of a quantum two level system based on two electron spin states in a double quantum dot, allowing state preparation, coherent manipulation, and projective readout. These techniques are based on rapid electrical control of the exchange interaction. Separating and later recombining a singlet spin state provided a measurement of the spin dephasing time, T2* of ~10 nanoseconds, limited by hyperfine interactions with the gallium arsenide host nuclei. Rabi oscillations of two electron spin states were demonstrated, and spin echo pulse sequences were used to suppress hyperfine induced dephasing. Using these quantum control techniques, a coherence time for two electron spin states exceeding 1 microsecond was observed.", "author_names": [ "Jason R Petta", "A C Johnson", "J M Taylor", "E A Laird", "Amir Yacoby", "Mikhail D Lukin", "Charles M Marcus", "Micah P Hanson", "Arthur C Gossard" ], "corpus_id": 9107033, "doc_id": "9107033", "n_citations": 2048, "n_key_citations": 67, "score": 0, "title": "Coherent Manipulation of Coupled Electron Spins in Semiconductor Quantum Dots", "venue": "Science", "year": 2005 }, { "abstract": "We propose an implementation of a universal set of one and two quantum bit gates for quantum computation using the spin states of coupled single electron quantum dots. Desired operations are effected by the gating of the tunneling barrier between neighboring dots. Several measures of the gate quality are computed within a recently derived spin master equation incorporating decoherence caused by a prototypical magnetic environment. Dot array experiments that would provide an initial demonstration of the desired nonequilibrium spin dynamics are proposed.", "author_names": [ "Daniel Loss", "David P DiVincenzo" ], "corpus_id": 13152124, "doc_id": "13152124", "n_citations": 4621, "n_key_citations": 99, "score": 0, "title": "Quantum computation with quantum dots", "venue": "", "year": 1998 }, { "abstract": "The ability to control the quantum state of a single electron spin in a quantum dot is at the heart of recent developments towards a scalable spin based quantum computer. In combination with the recently demonstrated controlled exchange gate between two neighbouring spins, driven coherent single spin rotations would permit universal quantum operations. Here, we report the experimental realization of single electron spin rotations in a double quantum dot. First, we apply a continuous wave oscillating magnetic field, generated on chip, and observe electron spin resonance in spin dependent transport measurements through the two dots. Next, we coherently control the quantum state of the electron spin by applying short bursts of the oscillating magnetic field and observe about eight oscillations of the spin state (so called Rabi oscillations) during a microsecond burst. These results demonstrate the feasibility of operating single electron spins in a quantum dot as quantum bits.", "author_names": [ "Frank H L Koppens", "Christo Buizert", "Klaas-Jan Tielrooij", "I T Vink", "Katja C Nowack", "Tristan Meunier", "L P Kouwenhoven", "Lieven M K Vandersypen" ], "corpus_id": 4351827, "doc_id": "4351827", "n_citations": 942, "n_key_citations": 23, "score": 0, "title": "Driven coherent oscillations of a single electron spin in a quantum dot", "venue": "Nature", "year": 2006 }, { "abstract": "We investigate the effects of the orientation of the magnetic field and the orientation of a quantum dot, with respect to crystallographic coordinates, on the quality of an electrically controlled qubit realized in a gated semiconductor quantum dot. We find that, due to the anisotropy of the spin orbit interactions, by varying the two orientations it is possible to tune the qubit in the sense of optimizing the ratio of its couplings to phonons and to a control electric field. We find conditions under which such optimal setup can be reached by solely reorienting the magnetic field, and when a specific positioning of the dot is required. We also find that the knowledge of the relative sign of the spin orbit interaction strengths allows to choose a robust optimal dot geometry, with the dot main axis along [110] or [110] where the qubit can be always optimized by reorienting the magnetic field. (c) 2016 American Physical Society. (Less)", "author_names": [ "Ognjen Malkoc", "Peter Stano", "Daniel Loss" ], "corpus_id": 54043726, "doc_id": "54043726", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Optimal geometry of lateral GaAs and Si/SiGe quantum dots for electrical control of spin qubits", "venue": "", "year": 2016 }, { "abstract": "The canonical example of a quantum mechanical two level system is spin. The simplest picture of spin is a magnetic moment pointing up or down. The full quantum properties of spin become apparent in phenomena such as superpositions of spin states, entanglement among spins, and quantum measurements. Many of these phenomena have been observed in experiments performed on ensembles of particles with spin. Only in recent years have systems been realized in which individual electrons can be trapped and their quantum properties can be studied, thus avoiding unnecessary ensemble averaging. This review describes experiments performed with quantum dots, which are nanometer scale boxes defined in a semiconductor host material. Quantum dots can hold a precise but tunable number of electron spins starting with 0, 1, 2, etc. Electrical contacts can be made for charge transport measurements and electrostatic gates can be used for controlling the dot potential. This system provides virtually full control over individual electrons. This new, enabling technology is stimulating research on individual spins. This review describes the physics of spins in quantum dots containing one or two electrons, from an experimentalist's viewpoint. Various methods for extracting spin properties from experiment are presented, restricted exclusively to electrical measurements. Furthermore, experimental techniques are discussed that allow for 1 the rotation of an electron spin into a superposition of up and down, 2 the measurement of the quantum state of an individual spin, and 3 the control of the interaction between two neighboring spins by the Heisenberg exchange interaction. Finally, the physics of the relevant relaxation and dephasing mechanisms is reviewed and experimental results are compared with theories for spin orbit and hyperfine interactions. All these subjects are directly relevant for the fields of quantum information processing and spintronics with single spins i.e. single spintronics.", "author_names": [ "Ronald Hanson", "L P Kouwenhoven", "Jason R Petta", "Seigo Tarucha", "Lieven M K Vandersypen" ], "corpus_id": 9107975, "doc_id": "9107975", "n_citations": 1700, "n_key_citations": 53, "score": 0, "title": "Spins in few electron quantum dots", "venue": "", "year": 2007 }, { "abstract": "Nanofabricated quantum bits permit large scale integration but usually suffer from short coherence times due to interactions with their solid state environment. The outstanding challenge is to engineer the environment so that it minimally affects the qubit, but still allows qubit control and scalability. Here, we demonstrate a long lived single electron spin qubit in a Si/SiGe quantum dot with all electrical two axis control. The spin is driven by resonant microwave electric fields in a transverse magnetic field gradient from a local micromagnet, and the spin state is read out in the single shot mode. Electron spin resonance occurs at two closely spaced frequencies, which we attribute to two valley states. Thanks to the weak hyperfine coupling in silicon, a Ramsey decay timescale of 1 ms is observed, almost two orders of magnitude longer than the intrinsic timescales in GaAs quantum dots, whereas gate operation times are comparable to those reported in GaAs. The spin echo decay time is ~40 ms, both with one and four echo pulses, possibly limited by intervalley scattering. These advances strongly improve the prospects for quantum information processing based on quantum dots.", "author_names": [ "Erika Kawakami", "P Scarlino", "Daniel R Ward", "Floris R Braakman", "Donald E Savage", "Max G Lagally", "Mark Friesen", "Susan N Coppersmith", "M A Eriksson", "Lieven M K Vandersypen" ], "corpus_id": 20106750, "doc_id": "20106750", "n_citations": 302, "n_key_citations": 4, "score": 0, "title": "Electrical control of a long lived spin qubit in a Si/SiGe quantum dot.", "venue": "Nature nanotechnology", "year": 2014 }, { "abstract": "Recent theory predicted that the quantum spin Hall effect, a fundamentally new quantum state of matter that exists at zero external magnetic field, may be realized in HgTe/(Hg,Cd)Te quantum wells. We fabricated such sample structures with low density and high mobility in which we could tune, through an external gate voltage, the carrier conduction from n type to p type, passing through an insulating regime. For thin quantum wells with well width d 6.3 nanometers, the insulating regime showed the conventional behavior of vanishingly small conductance at low temperature. However, for thicker quantum wells (d 6.3 nanometers) the nominally insulating regime showed a plateau of residual conductance close to 2e2/h, where e is the electron charge and h is Planck's constant. The residual conductance was independent of the sample width, indicating that it is caused by edge states. Furthermore, the residual conductance was destroyed by a small external magnetic field. The quantum phase transition at the critical thickness, d 6.3 nanometers, was also independently determined from the magnetic field induced insulator to metal transition. These observations provide experimental evidence of the quantum spin Hall effect.", "author_names": [ "Markus Konig", "Steffen Wiedmann", "Christoph Brune", "Andreas Roth", "Hartmut Buhmann", "Laurens W Molenkamp", "Xiao-liang Qi", "Shou-Cheng Zhang" ], "corpus_id": 8836690, "doc_id": "8836690", "n_citations": 3349, "n_key_citations": 41, "score": 0, "title": "Quantum Spin Hall Insulator State in HgTe Quantum Wells", "venue": "Science", "year": 2007 }, { "abstract": "Quantum computers promise to exceed the computational efficiency of ordinary classical machines because quantum algorithms allow the execution of certain tasks in fewer steps. But practical implementation of these machines poses a formidable challenge. Here I present a scheme for implementing a quantum mechanical computer. Information is encoded onto the nuclear spins of donor atoms in doped silicon electronic devices. Logical operations on individual spins are performed using externally applied electric fields, and spin measurements are made using currents of spin polarized electrons. The realization of such a computer is dependent on future refinements of conventional silicon electronics.", "author_names": [ "Bruce E Kane" ], "corpus_id": 8470520, "doc_id": "8470520", "n_citations": 2709, "n_key_citations": 69, "score": 0, "title": "A silicon based nuclear spin quantum computer", "venue": "Nature", "year": 1998 }, { "abstract": "We demonstrate coherent driving of a single electron spin using second harmonic excitation in a Si/SiGe quantum dot. Our estimates suggest that the anharmonic dot confining potential combined with a gradient in the transverse magnetic field dominates the second harmonic response. As expected, the Rabi frequency depends quadratically on the driving amplitude, and the periodicity with respect to the phase of the drive is twice that of the fundamental harmonic. The maximum Rabi frequency observed for the second harmonic is just a factor of 2 lower than that achieved for the first harmonic when driving at the same power. Combined with the lower demands on microwave circuitry when operating at half the qubit frequency, these observations indicate that second harmonic driving can be a useful technique for future quantum computation architectures.", "author_names": [ "P Scarlino", "Erika Kawakami", "Daniel R Ward", "Donald E Savage", "Max G Lagally", "Mark Friesen", "Susan N Coppersmith", "Mark A Eriksson", "Lieven M K Vandersypen" ], "corpus_id": 15509975, "doc_id": "15509975", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Second Harmonic Coherent Driving of a Spin Qubit in a Si/SiGe Quantum Dot.", "venue": "Physical review letters", "year": 2015 }, { "abstract": "We implement a technique for measuring the singlet triplet energy splitting responsible for spin to charge conversion in semiconductor quantum dots. This method, which requires fast, single shot charge measurement, reliably extracts an energy in the limits of both large and small splittings. We perform this technique on an undoped, accumulation mode Si/SiGe triple quantum dot and find that the measured splitting varies smoothly as a function of confinement gate biases. Not only does this demonstration prove the value of having an $in~situ$ excited state measurement technique as part of a standard tune up procedure, it also suggests that in typical Si/SiGe quantum dot devices, spin blockade can be limited by lateral orbital excitation energy rather than valley splitting.", "author_names": [ "Emily J Pritchett", "Tyler E Keating", "R W Andrews", "Jacob Z Blumoff", "L A De Lorenzo", "K Eng", "Andrey A Kiselev", "Se'an M Meenehan", "Seth T Merkel", "L F Edge", "Matthew T Rakher", "M G Borselli", "Andrew T Hunter" ], "corpus_id": 119394444, "doc_id": "119394444", "n_citations": 13, "n_key_citations": 2, "score": 1, "title": "Spin Blockade Spectroscopy of Si Si Ge Quantum Dots", "venue": "Physical Review Applied", "year": 2019 } ]

[ { "abstract": "Semiconductor quantum dots of few nanometers have demonstrated a great potential for bioimaging. The size determines the emitted color, but it is also expected to play an important role in the image brightness. In this work, the size dependence of the fluorescence quantum yield of the highly thermal sensitive CdTe quantum dots has been systematically investigated by thermal lens spectroscopy. It has been found that an optimum quantum yield is reached for 3.8 nm quantum dots. The presence of this optimum size has been corroborated in both one photon excited fluorescence experiments and two photon fluorescence microscopy of dot incubated cancer cells. Combination of quantum yield and fluorescence decay time measurements supports that the existence of this optimum size emerges from the interplay between the frequency dependent radiative emission rate and the size dependent coupling strength between bulk excitons and surface trapping states.", "author_names": [ "Laura Martinez Maestro", "Carlos Jacinto", "Ueslen Rocha", "M Carmen Iglesias-de la Cruz", "Francisco Sanz-Rodriguez", "Angeles Juarranz", "Jose Garcia Sole", "Daniel Jaque" ], "corpus_id": 73547777, "doc_id": "73547777", "n_citations": 30, "n_key_citations": 0, "score": 1, "title": "Optimum quantum dot size for highly efficient fluorescence bioimaging", "venue": "", "year": 2012 }, { "abstract": "Carbon dots (CDs) are a new class of photoluminescent (PL) biocompatible, environment friendly, and low cost carbon nanomaterials. Synthesis of highly efficient red emitting carbon dots (R CDs) on a gram scale is a great challenge at present, which heavily restricts the wide applications of CDs in the bioimaging field. Herein, R CDs with a high quantum yield (QY) of 53% are produced on a gram scale by heating a formamide solution of citric acid and ethylenediamine. The as prepared R CDs have an average size of 4.1 nm and a nitrogen content of about 30% with an excitation independent emission at 627 nm. After detailed characterizations, such strong red fluorescence is ascribed to the contribution from the nitrogen and oxygen related surface states and the nitrogen derived structures in the R CD cores. Our R CDs show good photostability and low cytotoxicity, and thus they are excellent red fluorescence probes for bioimaging both in vitro and in vivo.", "author_names": [ "Hui Ding", "Ji-Shi Wei", "Ning Zhong", "Q Y Gao", "Huan-Ming Xiong" ], "corpus_id": 39420119, "doc_id": "39420119", "n_citations": 114, "n_key_citations": 3, "score": 0, "title": "Highly Efficient Red Emitting Carbon Dots with Gram Scale Yield for Bioimaging.", "venue": "Langmuir the ACS journal of surfaces and colloids", "year": 2017 }, { "abstract": "Abstract Herein, highly blue graphitic carbon nitride quantum dots (g CNQDs) were synthesized by one step microwave assisted evaporation condensation strategy using bulk g C 3 N 4 as the precursor within 5 min. In contrast with conventional chemical routes, the as synthesized g CNQDs exhibited a high crystalline quality, excellent fluorescence characteristics, and a narrow size distribution with an average diameter of 3.5 0.5 nm. More importantly, by using a household microwave oven, this method has the advantages of wide accessibility, environmental friendliness, a high yield of ~40% and can be facilely synthesized in a large scale (scaled up to a gram scale) Notably, owing to the absence of any organic reagents, the blueas prepared g CNQDs show the excitation wavelength independent photoluminescence (PL) behavior. Moreover, benefiting from the stable PL emission, good water solubility, and extraordinary biocompatibility with a high quantum yield of ~17% the fluorescent g CNQDs can serve as a potential sensitive and selective probe for Fe 3+ detection with a super low detection limit of 2 nM and an effective labeling agent for live cell imaging. This work provides a unique opportunity to obtain g CNQDs in large scale via a facile route, which may pave the way for the further design of g CNQDs with other applications.", "author_names": [ "Ying Yin", "Yumin Zhang", "Tangling Gao", "Tai Yao", "Jiecai Han", "Zhengbin Han", "Zhihua Zhang", "Qiong Wu", "Bo Song" ], "corpus_id": 99902193, "doc_id": "99902193", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "One pot evaporation condensation strategy for green synthesis of carbon nitride quantum dots: An efficient fluorescent probe for ion detection and bioimaging", "venue": "", "year": 2017 }, { "abstract": "In this work, uniform molybdenum disulfide (MoS2)/tungsten disulfide (WS2) quantum dots are synthesized by the combination of sonication and solvothermal treatment of bulk MoS2/WS2 at a mild temperature. The resulting products possess monolayer thickness with an average size about 3 nm. The highly exfoliated and defect rich structure renders these quantum dots plentiful active sites for the catalysis of hydrogen evolution reaction (HER) The MoS2 quantum dots exhibit a small HER overpotential of 120 mV and long term durability. Moreover, the strong fluorescence, good cell permeability, and low cytotoxicity make them promising and biocompatible probes for in vitro imaging. In addition, this work may provide an alternative facile approach to synthesize the quantum dots of transition metal dichalcogenides or other layered materials on a large scale.", "author_names": [ "Shengjie Xu", "Dian Yi Li", "Peiyi Wu" ], "corpus_id": 95587625, "doc_id": "95587625", "n_citations": 546, "n_key_citations": 1, "score": 0, "title": "One Pot, Facile, and Versatile Synthesis of Monolayer MoS 2 /WS 2 Quantum Dots as Bioimaging Probes and Efficient Electrocatalysts for Hydrogen Evolution Reaction", "venue": "", "year": 2015 }, { "abstract": "This paper presents the synthesis of aqueous cadmium sulfide (CdS) quantum dots (QDs) and silica encapsulated CdS QDs by reverse microemulsion method and utilized as targeted bio optical probes. We report the role of CdS as an efficient cell tag with fluorescence on par with previously documented cadmium telluride and cadmium selenide QDs, which have been considered to impart high levels of toxicity. In this study, the toxicity of bare QDs was efficiently quenched by encapsulating them in a biocompatible coat of silica. The toxicity profile and uptake of bare CdS QDs and silica coated QDs, along with the CD31 labeled, silica coated CdS QDs on human umbilical vein endothelial cells and glioma cells, were investigated. The effect of size, along with the time dependent cellular uptake of the nanomaterials, has also been emphasized. Enhanced, high specificity imaging toward endothelial cell lines in comparison with glioma cells was achieved with CD31 antibody conjugated nanoparticles. The silica coated nanomaterials exhibited excellent biocompatibility and greater photostability inside live cells, in addition to possessing an extended shelf life. In vivo biocompatibility and localization study of silica coated CdS QDs in medaka fish embryos, following direct nanoparticle exposure for 24 hours, authenticated the nanomaterials' high potential for in vivo imaging, augmented with superior biocompatibility. As expected, CdS QD treated embryos showed 100% mortality, whereas the silica coated QD treated embryos stayed viable and healthy throughout and after the experiments, devoid of any deformities. We provide highly cogent and convincing evidence for such silica coated QDs as a model nanoparticle in practice, to achieve in vitro and in vivo precision targeted imaging.", "author_names": [ "Srivani Veeranarayanan", "Aby Cheruvathoor Poulose", "Mohamed Sheikh Mohamed", "Yutaka Nagaoka", "Seiki Iwai", "Yuya Nakagame", "Shosaku Kashiwada", "Yasuhiko Yoshida", "Toru Maekawa", "D Sakthi Kumar" ], "corpus_id": 15177729, "doc_id": "15177729", "n_citations": 35, "n_key_citations": 1, "score": 0, "title": "Synthesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging", "venue": "International journal of nanomedicine", "year": 2012 }, { "abstract": "Recently, carbon dots (CDs) have been playing an increasingly important role in industrial production and biomedical field because of their excellent properties. As such, finding an efficient method to quickly synthesize a large scale of relatively high purity CDs is of great interest. Herein, a facile and novel microwave method has been applied to prepare nitrogen doped CDs (N doped CDs) within 8 min using L glutamic acid as the sole reaction precursor in the solid phase condition. The as prepared N doped CDs with an average size of 1.64 nm are well dispersed in aqueous solution. The photoluminescence of N doped CDs is pH sensitive and excitation dependent. The N doped CDs show a strong blue fluorescence with relatively high fluorescent quantum yield of 41.2% which remains stable even under high ionic strength. Since the surface is rich in oxygen containing functional groups, N doped CDs can be applied to selectively detect Fe(3+ with the limit of detection of 10( 5) M. In addition, they are also used for cellular bioimaging because of their high fluorescent intensity and nearly zero cytotoxicity. The solid phase microwave method seems to be an effective strategy to rapidly obtain high quality N doped CDs and expands their applications in ion detection and cellular bioimaging.", "author_names": [ "Guili He", "Minghan Xu", "Mengjun Shu", "Xiaolin Li", "Zhi Yang", "Lilin Zhang", "Yanjie Su", "Nantao Hu", "Yafei Zhang" ], "corpus_id": 10178593, "doc_id": "10178593", "n_citations": 42, "n_key_citations": 1, "score": 0, "title": "Rapid solid phase microwave synthesis of highly photoluminescent nitrogen doped carbon dots for Fe(3+ detection and cellular bioimaging.", "venue": "Nanotechnology", "year": 2016 }, { "abstract": "Near infrared emissive organic dots with a high fluorescence quantum efficiency (AEE dots) are prepared by using an amphiphilic polymer poly(styrene co maleic anhydride) (PSMA) as the co encapsulation matrix and a novel small molecule fluorogen (DPPBPA) with high near infrared emission as the core. The PSMA dots show small particle size of about 20 nm, a large Stokes shift of 304 nm and really high fluorescence quantum efficiency of 20% The streptavidin dots are obtained by conjugating streptavidin to carboxyl groups on the surface of PSMA dots. These streptavidin dots can effectively and specifically label the target cell without any nonspecific binding, such as MCF 7 cells. Together with the negligible cytotoxicity, the near infrared emissive AEE dots are promising red fluorescent probes for future bioimaging applications.", "author_names": [ "Yan Zhang", "Kaiwen Chang", "Bin Xu", "Jinlong Chen", "Lulin Yan", "Suqian Ma", "Changfeng Wu", "Wenjing Tian" ], "corpus_id": 95325905, "doc_id": "95325905", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Highly efficient near infrared organic dots based on novel AEE fluorogen for specific cancer cell imaging", "venue": "", "year": 2015 }, { "abstract": "Abstract Halophenols (HPs) inflict adverse impacts on human and environment due to their toxic, carcinogenic as well as teratogenic properties. Additionally, it is of great importance and urgency for the development of simple, efficient and inexpensive approaches to minimize the harm of HPs. Here we report an innovatively making poison profitable method to prepare carbon dots (C dots) using 3 bromophenol residual as a precursor. The effects of solvent and carbonization temperature on the preparation of insecticide based C dots were investigated. The results indicate that higher organic solvent content in solution and higher carbonization temperature are in favor of the formation of C dots with smaller size and higher quantum yields. Meanwhile, all C dots displayed excellent water solubility and high photostability against ionic strengths and light illumination. The possible mechanisms of polymerization and carbonization of C dots were rationally proposed, and the incompact framework structure of C dots was reasonably inferred by room temperature phosphorescence measurement. Also, a kind of low toxicity, good biocompatibility and photostability C dots, which were synthesized via a lab leveled mimetic insecticide residuals approach, were utilized as colorless inks for printing patterns and as fluorescence probe for bioimaging. This proposed approach opened up a potential prospect to efficiently utilize pesticide residuals and other hazardous chemicals for biolabeling and bioimaging.", "author_names": [ "Wen-sheng Zou", "Yazhou Ji", "Xiufang Wang", "Qingyue Zhao", "Junxiang Zhang", "Qun Shao", "Jin Liu", "Feng Wang", "Ya-qin Wang" ], "corpus_id": 101251011, "doc_id": "101251011", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Insecticide as a precursor to prepare highly bright carbon dots for patterns printing and bioimaging: A new pathway for making poison profitable", "venue": "", "year": 2016 }, { "abstract": "In this study, a new imaging mesoporous nanoparticle is reported with exceptionally efficient and stable fluorescence emission, which was constructed by embedding and stabilizing quantum dots (QDs) of different sizes into porous nanobeads, following a lipid PEG2000 COOH coating which was further encoded with cRGD targeting peptide through biotin streptavidin bridges. The mesopores had ~10 nm diameter, were chemically modified, and facilitated internalization and stabilization of the QDs within the nanobeads upon the preparation protocol. Their outstanding optical contrasts render the highly fluorescent QDs as ideal fluorophores for wavelength and intensity multiplex color coding. The QDs tagged nanobeads showed optically strong and chemically stable imaging capability, both in vitro and in vivo, indicating powerful contrast modality among other alternatives. The cRGD encoded lipid coated QDs tagged nanobeads (cRGD encoded LQNBs) exhibited significantly increased avb3 expressing cell targeting toward MCF 7 breast cancer cells over the avb3 low expressing in HeLa cervix cancer cells, as confirmed by confocal laser scanning microscopy and flow cytometry. In MCF 7 xenograft nude mice, the cRGD encoded LQNBs revealed prolonged accumulation time at the tumor site. In addition, the QNBs also demonstrated relatively high cell viability as compared to 3 mercaptopropionic acid (MPA) functionalized QDs, indicating a successful design of highly cytocompatible nanoparticulate platform capable of providing cell specific targeting and nano imaging modalities for biomedical applications.", "author_names": [ "Po-Jung Chen", "Shang-Hsiu Hu", "Wen-Ting Hung", "San-Yuan Chen", "Dean-Mo Liu" ], "corpus_id": 54590407, "doc_id": "54590407", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Geometrical confinement of quantum dots in porous nanobeads with ultraefficient fluorescence for cell specific targeting and bioimaging", "venue": "", "year": 2012 }, { "abstract": "Carbon dots with long wavelength emissions, high quantum yield (QY) and good biocompatibility are highly desirable for biomedical applications. Herein, a green, facile hydrothermal synthesis of highly efficient red emissive nitrogen doped carbonized polymer dots (CPDs) with optimal emission at around 630 nm are reported. The red emissive CPDs possess a variety of superior properties including excellent water dispersibility, good biocompatibility, narrow bandwidth emission, an excitation independent emission, and high QY (10.83% (in water) and 31.54% (in ethanol) Further studies prove that such strong red fluorescence is ascribed to the efficient conjugated aromatic p systems and hydrogen bonds of CPDs. And the fluorescence properties of CPDs can be regulated by adjusting the dosage of HNO3 before the reaction. Additionally, the as prepared CPDs are successfully used as a fluorescent probe for bioimaging, both in vitro and in vivo. More importantly, biodistribution results demonstrate that most CPDs and their metabolites are not only excreted in urine but also excreted by hepatobiliary system in a rapid manner. Besides, the CPDs could easily cross the blood brain barrier, which may provide a valuable strategy for the theranostics of some brain diseases through real time tracking.", "author_names": [ "Junjun Liu", "Daowei Li", "Kai Zhang", "Mingxi Yang", "Hongchen Sun", "Bai Yang" ], "corpus_id": 3664843, "doc_id": "3664843", "n_citations": 163, "n_key_citations": 0, "score": 0, "title": "One Step Hydrothermal Synthesis of Nitrogen Doped Conjugated Carbonized Polymer Dots with 31% Efficient Red Emission for In Vivo Imaging.", "venue": "Small", "year": 2018 } ]

[ { "abstract": "This paper deals with increasing the reliability of electric drives of exhausters of the oxygen converter process. The dependences of the reliability parameters in the electrical converter electric motor system on the power reserve were obtained. The costs for the installed equipment were taken as an optimization criterion. It is noted that improving the reliability of an electric drive is possible both by increasing the overall power of the power unit and by changing the number of phases. It is shown that the reliability of the system can be improved in a synchronous electric drive with pulse vector control at the reservation of a semiconductor converter. A mathematical model of the electrical converter reluctance motor with a field regulated machine complex is proposed. The results of the mathematical modeling of the synchronous electric drive with pulse vector control are considered. The dependence of the specific electric parameters on the number of phases is determined.", "author_names": [ "M A Grigor'ev", "Dmitry Sychev", "Artyom M Zhuravlev", "Evgeny S Khayatov", "Nikita V Savosteenko" ], "corpus_id": 113213051, "doc_id": "113213051", "n_citations": 45, "n_key_citations": 1, "score": 1, "title": "Improving the reliability of electric drives of exhausters of the oxygen converter process", "venue": "", "year": 2015 }, { "abstract": "With the requirements for reducing emissions and improving fuel economy, automotive companies are developing electric, hybrid electric, and plug in hybrid electric vehicles. Power electronics is an enabling technology for the development of these environmentally friendlier vehicles and implementing the advanced electrical architectures to meet the demands for increased electric loads. In this paper, a brief review of the current trends and future vehicle strategies and the function of power electronic subsystems are described. The requirements of power electronic components and electric motor drives for the successful development of these vehicles are also presented.", "author_names": [ "Ali Emadi", "Young-Joo Lee", "Kaushik Rajashekara" ], "corpus_id": 20821804, "doc_id": "20821804", "n_citations": 1082, "n_key_citations": 32, "score": 0, "title": "Power Electronics and Motor Drives in Electric, Hybrid Electric, and Plug In Hybrid Electric Vehicles", "venue": "IEEE Transactions on Industrial Electronics", "year": 2008 }, { "abstract": "Electric traction is one of the most promising technologies that can lead to significant improvements in vehicle performance, energy utilization efficiency, and polluting emissions. Among several technologies, hybrid electric vehicle (HEV) traction is the most promising technology that has the advantages of high performance, high fuel efficiency, low emissions, and long operating range. Moreover, the technologies of all the component hardware are technically and markedly available. At present, almost all the major automotive manufacturers are developing hybrid electric vehicles, and some of them have marketed their productions, such as Toyota and Honda. This paper reviews the present technologies of HEVs in the range of drivetrain configuration, electric motor drives, and energy storages", "author_names": [ "Mehrdad Ehsani", "Yimin Gao", "JohnM Miller" ], "corpus_id": 29964502, "doc_id": "29964502", "n_citations": 416, "n_key_citations": 21, "score": 0, "title": "Hybrid Electric Vehicles: Architecture and Motor Drives", "venue": "Proceedings of the IEEE", "year": 2007 }, { "abstract": "The fuel economy and all electric range (AER) of hybrid electric vehicles (HEVs) are highly dependent on the onboard energy storage system (ESS) of the vehicle. Energy storage devices charge during low power demands and discharge during high power demands, acting as catalysts to provide energy boost. Batteries are the primary energy storage devices in ground vehicles. Increasing the AER of vehicles by 15% almost doubles the incremental cost of the ESS. This is due to the fact that the ESS of HEVs requires higher peak power while preserving high energy density. Ultracapacitors (UCs) are the options with higher power densities in comparison with batteries. A hybrid ESS composed of batteries, UCs, and/or fuel cells (FCs) could be a more appropriate option for advanced hybrid vehicular ESSs. This paper presents state of the art energy storage topologies for HEVs and plug in HEVs (PHEVs) Battery, UC, and FC technologies are discussed and compared in this paper. In addition, various hybrid ESSs that combine two or more storage devices are addressed.", "author_names": [ "Alireza Khaligh", "Zhihao Li" ], "corpus_id": 271538, "doc_id": "271538", "n_citations": 1258, "n_key_citations": 42, "score": 0, "title": "Battery, Ultracapacitor, Fuel Cell, and Hybrid Energy Storage Systems for Electric, Hybrid Electric, Fuel Cell, and Plug In Hybrid Electric Vehicles: State of the Art", "venue": "IEEE Transactions on Vehicular Technology", "year": 2010 }, { "abstract": "Environmental Impact and History of Modern Transportation Air Pollution Global Warming Petroleum Resources Induced Costs Importance of Different Transportation Development Strategies to Future Oil Supply History of EVs History of HEVs History of Fuel Cell Vehicles Fundamentals of Vehicle Propulsion and Brake General Description of Vehicle Movement Vehicle Resistance Dynamic Equation Tire Ground Adhesion and Maximum Tractive Effort Power Train Tractive Effort and Vehicle Speed Vehicle Power Plant and Transmission Characteristics Vehicle Performance Operating Fuel Economy Brake Performance Internal Combustion Engines 4S, Spark Ignited IC Engines 4S, Compression Ignition IC Engines 2S Engines Wankel Rotary Engines Stirling Engines Gas Turbine Engines Quasi Isothermal Brayton Cycle Engines Electric Vehicles Configurations of EVs Performance of EVs Tractive Effort in Normal Driving Energy Consumption Hybrid Electric Vehicles Concept of Hybrid Electric Drive Trains Architectures of Hybrid Electric Drive Trains Electric Propulsion Systems DC Motor Drives Induction Motor Drives Permanent Magnetic BLDC Motor Drives SRM Drives Design Principle of Series (Electrical Coupling) Hybrid Electric Drive Train Operation Patterns Control Strategies Design Principles of a Series (Electrical Coupling) Hybrid Drive Train Design Example Parallel (Mechanically Coupled) Hybrid Electric Drive Train Design Drive Train Configuration and Design Objectives Control Strategies Parametric Design of a Drive Train Simulations Design and Control Methodology of Series Parallel (Torque and Speed Coupling) Hybrid Drive Train Drive Train Configuration Drive Train Control Methodology Drive Train Parameters Design Simulation of an Example Vehicle Design and Control Principles of Plug In Hybrid Electric Vehicles Statistics of Daily Driving Distance Energy Management Strategy Energy Storage Design Mild Hybrid Electric Drive Train Design Energy Consumed in Braking and Transmission Parallel Mild Hybrid Electric Drive Train Series Parallel Mild Hybrid Electric Drive Train Peaking Power Sources and Energy Storages Electrochemical Batteries Ultracapacitors Ultra High Speed Flywheels Hybridization of Energy Storages Fundamentals of Regenerative Breaking Braking Energy Consumed in Urban Driving Braking Energy versus Vehicle Speed Braking Energy versus Braking Power Braking Power versus Vehicle Speed Braking Energy versus Vehicle Deceleration Rate Braking Energy on Front and Rear Axles Brake System of EV, HEV, and FCV Fuel Cells Operating Principles of Fuel Cells Electrode Potential and Current Voltage Curve Fuel and Oxidant Consumption Fuel Cell System Characteristics Fuel Cell Technologies Fuel Supply Non Hydrogen Fuel Cells Fuel Cell Hybrid Electric Drive Train Design Configuration Control Strategy Parametric Design Design Example Design of Series Hybrid Drive Train for Off Road Vehicles Motion Resistance Tracked Series Hybrid Vehicle Drive Train Architecture Parametric Design of the Drive Train Engine/Generator Power Design Power and Energy Design of Energy Storage Appendices Index", "author_names": [ "Mehrdad Ehsani", "Yimin Gao", "Ali Emadi" ], "corpus_id": 197405646, "doc_id": "197405646", "n_citations": 1652, "n_key_citations": 125, "score": 0, "title": "Modern electric, hybrid electric, and fuel cell vehicles fundamentals, theory, and design", "venue": "", "year": 2009 }, { "abstract": "s of the 59th Meeting (Spring Meeting) March 26 30, 1 984, Dortmund Springer International", "author_names": [ "Deutsche Physiologische Gesellschaft Abstracts of the 54 M Organizers" ], "corpus_id": 3594836, "doc_id": "3594836", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Deutsche Physiologische Gesellschaft Abstracts of the 59th Meeting (Spring Meeting) March 26 30, 1984, Dortmund", "venue": "Pflugers Archiv", "year": 2004 }, { "abstract": "Note from the Series Editor. Foreword. Preface. Acknowledgments. Chapter 1: Introduction. 1.1 Electric Propulsion Background. 1.2 Electric Thruster Types. 1.3 Ion Thruster Geometry. 1.4 Hall Thruster Geometry. 1.5 Beam/Plume Characteristics. References. Chapter 2: Thruster Principles. 2.1 The Rocket Equation. 2.2 Force Transfer in Ion and Hall Thrusters. 2.3 Thrust. 2.4 Specific Impulse. 2.5 Thruster Efficiency. 2.6 Power Dissipation. 2.7 Neutral Densities and Ingestion in Electric Thrusters. References. Problems. Chapter 3: Basic Plasma Physics. 3.1 Introduction. 3.2 Maxwell's Equations. 3.3 Single Particle Motions. 3.4 particle Energies and Velocities. 3.5 Plasma as a Fluid. 3.6 Diffusion in Partially Ionized Gases. 3.7 Sheaths at the Boundaries of Plasmas. References. Problems. Chapter 4: Ion Thruster Plasma Generators. 4.1 Introduction. 4.2 Idealized Ion Thruster Plasma Generator. 4.3 DC Discharge Ion Thruster. 4.4 Kaufman Ion Thrusters. 4.5 rf Ion Thrusters. 4.6 Microwave Ion Thrusters. 4.7 2 D Computer Models of the Ion Thruster Discharge Chamber. References. Problems. Chapter 5: Ion Thruster Accelerator Grids. 5.1 Grid Configurations. 5.2 Ion Accelerator Basics. 5.3 Ion Optics. 5.4 Electron Backstreaming. 5.5 High Voltage Considerations. 5.6 Ion Accelerator Grid Life. References. Problems. Chapter 6: Hollow Cathodes. 6.1 Introduction. 6.2 Cathode Configurations. 6.3 Thermionic Electron Emitter Characteristics. 6.4 Insert Region Plasma. 6.5 Orifice Region Plasma. 6.6 Hollow cathode Thermal Models. 6.7 Cathode Plume Region Plasma. 6.8 Hollow Cathode Life. 6.9 Keeper Wear and Life. 6.10 Hollow Cathode Operation. References. Problems. Chapter 7: Hall Thrusters. 7.1 Introduction. 7.2 Thruster Operating Principles and Scaling. 7.3 Hall Thruster Performance Models. 7.4 Channel Physics and Numerical Modeling. 7.5 Hall Thruster Life. References. Problems. Chapter 8: Ion and Hall Thruster Plumes. 8.1 Introduction. 8.2 Plume Physics. 8.3 Plume Models. 8.4 Spacecraft Interactions. 8.5 Interactions with Payloads. References. Problems. Chapter 9: Flight Ion and Hall Thrusters. 9.1 Introduction. 9.2 Ion Thrusters. 9.3 Hall Thrusters. References. Appendices. A: Nomenclature. B: Gas Flow Unit Conversions and Cathode Pressure Estimates. C: Energy Loss by Electrons. D: Ionization and Excitation Cross Sections for Xenon. E: Ionization and Excitation Reaction Rates for Xenon in Maxwellian Plasmas. F: Electron Relaxation and Thermalization Times. G: Clausing Factor Monte Carlo Calculation. Index.", "author_names": [ "Dan M Goebel", "Ira Katz" ], "corpus_id": 92746133, "doc_id": "92746133", "n_citations": 893, "n_key_citations": 137, "score": 0, "title": "Fundamentals of Electric Propulsion: Ion and Hall Thrusters", "venue": "", "year": 2008 }, { "abstract": "With the more stringent regulations on emissions and fuel economy, global warming, and constraints on energy resources, the electric, hybrid, and fuel cell vehicles have attracted more and more attention by automakers, governments, and customers. Research and development efforts have been focused on developing novel concepts, low cost systems, and reliable hybrid electric powertrain. This paper reviews the state of the art of electric, hybrid, and fuel cell vehicles. The topologies for each category and the enabling technologies are discussed", "author_names": [ "C C Chan" ], "corpus_id": 11487264, "doc_id": "11487264", "n_citations": 1609, "n_key_citations": 94, "score": 0, "title": "The State of the Art of Electric, Hybrid, and Fuel Cell Vehicles", "venue": "Proceedings of the IEEE", "year": 2007 }, { "abstract": "ing Department of General Electric Company at the Hanford Atomic Products Operation, where he is involved primarily with long range process development and/or improvements. He is a graduate of Brigham Young University, where he obtained a B.E.S. in chemical engineering. Prior to joining General Electric, Mr. Godfrey worked for American Potash and Chemical Corporation's Research Department as a research engineer concerned with pilot scale process development.", "author_names": [ "W L Godfrey", "R D Benham" ], "corpus_id": 208872604, "doc_id": "208872604", "n_citations": 2996, "n_key_citations": 129, "score": 0, "title": "Process", "venue": "", "year": 1965 }, { "abstract": "The increasing interest in energy storage for the grid can be attributed to multiple factors, including the capital costs of managing peak demands, the investments needed for grid reliability, and the integration of renewable energy sources. Although existing energy storage is dominated by pumped hydroelectric, there is the recognition that battery systems can offer a number of high value opportunities, provided that lower costs can be obtained. The battery systems reviewed here include sodium sulfur batteries that are commercially available for grid applications, redox flow batteries that offer low cost, and lithium ion batteries whose development for commercial electronics and electric vehicles is being applied to grid storage.", "author_names": [ "Bruce S Dunn", "Haresh Kamath", "Jean Marie Tarascon" ], "corpus_id": 206536979, "doc_id": "206536979", "n_citations": 8232, "n_key_citations": 56, "score": 0, "title": "Electrical Energy Storage for the Grid: A Battery of Choices", "venue": "Science", "year": 2011 } ]

[ { "abstract": "The scaling of complementary metal oxide semiconductor (CMOS) technology is increasingly challenging, but demand for low power data storage and processing continues to grow. The ability to generate, transport and manipulate spin signals in two dimensional (2D) materials suggests that they could provide a suitable platform to build beyond CMOS spintronic devices. Here we review the development of 2D spintronics and explore its potential to deliver devices and circuits for low power electronic applications. We examine the elementary spintronic functionalities and how they can be used to build electronic devices and circuits. We also consider the challenges that must be addressed to deliver practical memory and logic devices.This Review Article examines the development of two dimensional spintronics for low power electronics, exploring potential devices and circuits, as well the challenges that exist in delivering practical applications.", "author_names": [ "Xiaoyang Lin", "Wei Yang", "Kang L Wang", "Weisheng Zhao" ], "corpus_id": 197401960, "doc_id": "197401960", "n_citations": 103, "n_key_citations": 0, "score": 1, "title": "Two dimensional spintronics for low power electronics", "venue": "Nature Electronics", "year": 2019 }, { "abstract": "The successful isolation of graphene in 2004 has attracted great interest to search for potential applications of this unique material and other newborn members of the two dimensional (2D) family in electronics, optoelectronics, spintronics and other fields. Compared to graphene, the 2D transition metal dichalcogenides (TMDs) have the advantage of being semiconductors, which would allow their use for logic devices. In the past ten years, significant developments have been made in this area, where opportunities and challenges co exist.This thesis presents the results of quantum transport simulations of novel 2D material based tunnel field effect transistors for ultra low power digital applications. Due to their size, such devices are intrinsically dominated by quantum effects. This requires the adoption of a fairly general theory of transport, such as the nonequilibrium Green's functions (NEGF) formalism, which is a method extensively used for the simulation of electron transport in nanostructures.In the first part of this thesis, a brief introduction about the 2D materials, their synthesis and applications is presented. Then, the NEGF formalism is concisely reviewed. This approach is applied to the simulation of two different models of vertical tunnel field effect transistors based on 2D TMD van der Waal heterojunctions (MoS2 and WTe2) To properly describe the system, a coupled effective mass Hamiltonian has been implemented and carefully calibrated to experimental measurements and density functional theory to reproduce the band structure in the energy range of interest for the simulations.This thesis not only demonstrates the ultra steep subthreshold slope potentially expected for these devices, but also provides a physical insight into the impact of the transistor geometry on its performances. In the last and more exploratory part of the manuscript, the effect of rotational misalignment within the two layers of the heterostructure is investigated. Experimentally, such a disorder is difficult to avoid, and it can substantially affect the device performances.Through accurate quantum simulations and deep physical analysis, this study sheds light on the design challenges to be addressed for the development of efficient tunnel field effect transistors based on 2D materials.", "author_names": [ "Jiang Cao" ], "corpus_id": 67276338, "doc_id": "67276338", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Tunnel Field Effect Transistors Based on Two Dimensional Materials", "venue": "", "year": 2017 }, { "abstract": "Abstract A multi terminal hybrid system named memtransistor has recently been proposed by combining the concepts of both memristor and field effect transistor (FET) with two dimensional (2D) layered materials as the active semiconductor layer. In the memtransistors, the gate voltages are capable of modulating not only the transport properties of the fabricated FET, but also the resistive switching (RS) behaviors of the memristor. Herein, we employ mechanically exfoliated 2D layered GaSe nanosheets to prepare GaSe based three terminal memtransistors. By using Ag as the electrodes, the memristor exhibits non volatile bipolar RS characteristics. More importantly, under exposure to air for one week, the RS behaviors are dramatically enhanced with the ON/OFF ratio reaching up to 5.3 x 105 and ultralow threshold electric field of ~3.3 x 102 V cm 1. The ultralow threshold electric field of GaSe based memristor could be related to the low migration energy of the intrinsic Ga vacancy in p type GaSe. Moreover, the GaSe based memristor shows long term retention ~104 s) and high cycling endurance ~5000 cycles) simultaneously. Hence, the fabricated three terminal 2D GaSe memtransistors possess high performance with large switching ratios, ultralow threshold electric field, good endurance and long term retention. Furthermore, the device demonstrates gate tunability in RS characteristics, suggesting the promising applications in multi terminal electronic devices with low power consumption and complex functionalities, ranging from non volatile memory, logic device to neuromorphic computing.", "author_names": [ "Yang Yang", "Huiying Du", "Qiang Xue", "Xian-hua Wei", "Zhibin Yang", "Chenggang Xu", "Dunmin Lin", "Wenjing Jie", "Jianhua Hao" ], "corpus_id": 139797743, "doc_id": "139797743", "n_citations": 43, "n_key_citations": 1, "score": 0, "title": "Three terminal memtransistors based on two dimensional layered gallium selenide nanosheets for potential low power electronics applications", "venue": "Nano Energy", "year": 2019 }, { "abstract": "Magnetic orderings, i.e. the spontaneous alignment of electron spins below a critical temperature, have been playing key roles in modern science and technologies for both the wide applications of magnetic recording for information storage and the vibrant potential of solid state electronic spin devices (also known as spintronics) for logic operations. In the past decades, thanks to the development of thin film technologies, magnetic thin films via sputtering or epitaxial growth have made the spintronic devices possible at the industrial scale. Yet thinner materials at lower costs with more versatile functionalities are highly desirable for advancing future spintronics. Recently, van der Waals magnetic materials, a family of magnets that can in principle be exfoliated down to the monolayer limit, seem to have brought tremendous opportunities: new generation van der Waals spintronic devices can be seamlessly assembled with possible applications such as optoelectronics, flexible electronics, and etc. Moreover, those exfoliated spintronic devices can potentially be compatible with the famed metal oxide field effect transistor architectures, allowing the harness of spin performances through the knob of an electrostatic field.", "author_names": [ "Xiaoxi Li", "Baojuan Dong", "Xing Sun", "Hanwen Wang", "Teng Yang", "Guoqiang Yu", "Zheng Vitto Han" ], "corpus_id": 201287540, "doc_id": "201287540", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Perspectives on exfoliated two dimensional spintronics", "venue": "Journal of Semiconductors", "year": 2019 }, { "abstract": "Two dimensional materials can be exploited to make a new kind of electronic device that researchers have dubbed an atomristor. In early stage studies, the researchers have demonstrated a possible application for atomristors in low power communications circuits (Nano Lett. 2017, DOI: 10.1021/acs.nanolett.7b04342) The device's name comes from \"atomically thin memristor.\" Memristors are the odd cousin of the electronics family, capable of acting in ways similar to memory cells and transistors. They're particularly promising for use in computer memory because they are nonvolatile: Even when the power is turned off, they hold onto their data. Scientists are also exploring memristors for brainlike computing applications because the devices can both process and store information, like neurons do. And like real neurons, they can exist in a variety of states, not just as a 1 or a 0, because their electrical resistance can be varied along a continuum. Researchers believed that memristors could not", "author_names": [ "Katherine Bourzac" ], "corpus_id": 116538845, "doc_id": "116538845", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Two dimensional materials could enable low power telecommunications", "venue": "", "year": 2018 }, { "abstract": "To develop low power, high speed and area efficient design for portable electronics devices and signal processing applications is a very challenging task. Multiplier has an important role in digita.", "author_names": [ "Pankaj Kumar", "Rajender Kumar Sharma" ], "corpus_id": 21486311, "doc_id": "21486311", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Low Power and Area Efficient Parallel Multiplier Design Using Two Dimensional Bypassing", "venue": "J. Circuits Syst. Comput.", "year": 2017 }, { "abstract": "There has been an exponential growth in the microelectronics industry over the last 70 years with a consistent miniaturization of transistors' size and increase in the speed and on chip transistors density with reasonable power consumption, as seen in Figure 1 [1] This trend will saturate soon especially due to the unintended thermal noise that is dissipated, as the density of transistors on the chips increase and as the corresponding electronics approach their physical limits. There is a need to implement new processing and computing techniques [2] with more compact size, lower power consumption and enhanced performance. Neuromorphic computing mimics the parallel processing of the mammalian brain and the quantum decoherence within the neurons, and seems to be promising for future applications and needs high speed electronics [3] Quantum computing could enhance the functionalities, storage capabilities, and data manipulation and transmission, for the next generation of devices. Spintronics is an enabling technology to meet the speed, power, and scalability requirements for quantum information and neuromorphic computing [4 5] The non volatile nature of spintronic memory could help to tackle power efficiency challenges of microelectronics. Spin of a material is directly related with magnetic, electrical, and optical properties. It is necessary to investigate materials and understand their properties to control and manipulate their spin and use for spintronic applications. However, most materials show conducive properties for spintronics at cryogenic temperatures, which limits their practical applications. There is a need to investigate spintronic materials for quantum applications at room temperature (RT)", "author_names": [ "Vishal Saravade", "Amirhossein Ghods", "Andrew Woode", "Chuanle Zhou", "Ian T Ferguson" ], "corpus_id": 208211629, "doc_id": "208211629", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "GaN based Room Temperature Spintronics for Next Generation Low Power Consumption Electronic Devices", "venue": "2019 IEEE 16th International Conference on Smart Cities: Improving Quality of Life Using ICT IoT and AI (HONET ICT)", "year": 2019 }, { "abstract": "Abstract Synapses in biology provide a variety of functions for the neural system. Artificial synaptic electronics that mimic the biological neuron functions are basic building blocks and developing novel artificial synapses is essential for neuromorphic computation. Inspired by the unique features of biological synapses that the basic connection components of the nervous system and the parallelism, low power consumption, fault tolerance, self learning and robustness of biological neural systems, artificial synaptic electronics and neuromorphic systems have the potential to overcome the traditional von Neumann bottleneck and create a new paradigm for dealing with complex problems such as pattern recognition, image classification, decision making and associative learning. Nowadays, two dimensional (2D) materials have drawn great attention in simulating synaptic dynamic plasticity and neuromorphic computing with their unique properties. Here we describe the basic concepts of bio synaptic plasticity and learning, the 2D materials library and its preparation. We review recent advances in synaptic electronics and artificial neuromorphic systems based on 2D materials and provide our perspective in utilizing 2D materials to implement synaptic electronics and neuromorphic systems in hardware.", "author_names": [ "Shuiyuan Wang", "David-Wei Zhang", "Peng Zhou" ], "corpus_id": 91615768, "doc_id": "91615768", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Two dimensional materials for synaptic electronics and neuromorphic systems", "venue": "Science Bulletin", "year": 2019 }, { "abstract": "Schrodingerand Poisson equations are solved self consistently in order to obtain the potential and charge density distribution in n type GaN nanowalls tapered along c axis by different angles. The", "author_names": [ "Swarup Deb", "Subhabrata Dhar" ], "corpus_id": 139210798, "doc_id": "139210798", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Wedge Shaped GaN Nanowalls: A Potential Candidate for Two Dimensional Electronics and Spintronics", "venue": "", "year": 2018 }, { "abstract": "Gas sensors based on metal oxide semiconductor transistor with the polysilicon gate replaced by a gas sensitive thin film have been around for over 50 years. These are not suitable for the emerging mobile and wearable sensor platforms due to operating voltages and powers far exceeding the supply capability of batteries. Here we present a novel approach to decouple the chemically sensitive region from the conducting channel for reducing the drive voltage and increasing reliability. This chemically gated field effect transistor uses silicon nanowire for the current conduction channel with a tin oxide film on top of the nanowire serving as the gas sensitive medium. The potential change induced by the molecular adsorption and desorption allows the electrically floating tin oxide film to gate the silicon channel. As the device is designed to be normally off, the power is consumed only during the gas sensing event. This feature is attractive for the battery operated sensor and wearable electronics. In addition, the decoupling of the chemical reaction and the current conduction regions allows the gas sensitive material to be free from electrical stress, thus increasing reliability. The device shows excellent gas sensitivity to the tested analytes relative to conventional metal oxide transistors and resistive sensors.", "author_names": [ "Jin-Woo Han", "Taiuk Rim", "Chang-Ki Baek", "Meyya Meyyappan" ], "corpus_id": 23296016, "doc_id": "23296016", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Chemical Gated Field Effect Transistor by Hybrid Integration of One Dimensional Silicon Nanowire and Two Dimensional Tin Oxide Thin Film for Low Power Gas Sensor.", "venue": "ACS applied materials interfaces", "year": 2015 } ]

[ { "abstract": "Compares the organization of regional economies, focusing on Silicon Valley's thriving regional network based system and Route 128's declining independent firm based system. The history of California's Silicon Valley and Massachusetts' Route 128 as centers of innovation in the electronics indistry is traced since the 1970s to show how their network organization contributed to their ability to adapt to international competition. Both regions faced crises in the 1980s, when the minicomputers produced in Route 128 were replaced by personal computers, and Japanese competitors took over Silicon Valley's market for semiconductor memory. However, while corporations in the Route 128 region operated by internalization, using policies of secrecy and company loyalty to guard innovation, Silicon Valley fully utilized horizontal communication and open labor markets in addition to policies of fierce competition among firms. As a result, and despite mounting competition, Silicon Valley generated triple the number of new jobs between 1975 and 1990, and the market value of its firms increased $25 billion from 1986 to 1990 while Route 128 firms increased only $1 billion for the same time period. From analysis of these regions, it is clear that innovation should be a collective process, most successful when institutional and social boundaries dividing firms are broken down. A thriving regional economy depends not just on the initiative of individual entrepreneurs, but on an embedded network of social, technical, and commercial relationships between firms and external organizations. With increasingly fragmented markets, regional interdependencies rely on consistently renewed formal and informal relationships, as well as public funding for education, research, and training. Local industrial systems built on regional networks tend to be more flexible and technologically dynamic than do hierarchical, independent firm based systems in which innovation is isolated within the boundaries of corporations. (CJC)", "author_names": [ "Alfred Dupont Chandler", "AnnaLee Saxenian" ], "corpus_id": 147510409, "doc_id": "147510409", "n_citations": 6766, "n_key_citations": 489, "score": 1, "title": "Regional Advantage: Culture and Competition in Silicon Valley and Route 128", "venue": "", "year": 1994 }, { "abstract": "", "author_names": [ "Kevin John Morgan" ], "corpus_id": 152625238, "doc_id": "152625238", "n_citations": 315, "n_key_citations": 28, "score": 0, "title": "Regional advantage: Culture and competition in Silicon Valley and route 128: AnnaLee Saxenian, (Harvard University Press, Cambridge, MA, 1994) 226 pp; Price [UK pound]19.95, ISBN 0 674 75339 9", "venue": "", "year": 1996 }, { "abstract": "", "author_names": [ "Meric S Gertler", "Paivi Oinas", "Michael Storper", "Philip Scranton" ], "corpus_id": 156281509, "doc_id": "156281509", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "Discussion of Regional Advantage: Culture and Competition in Silicon Valley and Route 128 by AnnaLee Saxenian", "venue": "", "year": 1995 }, { "abstract": "", "author_names": [ "AnnaLee Saxenian" ], "corpus_id": 197825742, "doc_id": "197825742", "n_citations": 81, "n_key_citations": 4, "score": 0, "title": "Regional Advantage: Culture and Competition in Silicon Valley and Route 128, With a New Preface by the Author", "venue": "", "year": 1996 }, { "abstract": "", "author_names": [ "Linda Harris Dobkins" ], "corpus_id": 152591370, "doc_id": "152591370", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Regional advantage: Culture and competition in silicon valley and route 128: AnnaLee Saxenian, (Harvard University Press, Cambridge, 1994) pp. 226, $24.95", "venue": "", "year": 1997 }, { "abstract": "", "author_names": [ "Craig Wollner" ], "corpus_id": 155419492, "doc_id": "155419492", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Regional Advantage: Culture and Competition in Silicon Valley and Route 128. By Annalee Saxenian Cambridge, Mass. Harvard University Press, 1994. xi 226 pp. Figures, tables, notes, and index. $24.95. ISBN 0 674 75339 9.", "venue": "", "year": 1994 }, { "abstract": "", "author_names": [ "Joshua S Gans" ], "corpus_id": 154146731, "doc_id": "154146731", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Regional Advantage: Culture and Competition in Silicon Valley and Route 128 by Annalee Saxenian (Harvard University Press, Cambridge, 1994) xi 226 pp. US$24.95, ISBN 0 674 75339 9", "venue": "", "year": 1995 }, { "abstract": "From classical temples to twentieth century towers, engineers have learned more about design from failure than from success. The concept of error, according to the author of Design Paradigms, is central to the design process. As a way of explaining the enduring aspects of engineering design, Henry Petroski relates stories of some of the greatest engineering successes and failures of all time. These case studies, drawn from a wide range of times and places, from Ancient Greece and Rome to modem America, serve as paradigms of error and judgment in engineering design.", "author_names": [ "Martin Nov Goldstein", "Inge F Goldstein" ], "corpus_id": 220736192, "doc_id": "220736192", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Regional Advantage: Culture and Competition in Silicon Valley and Route 128, AnnaLee Saxenian. 1994. Harvard University Press, Cambridge, MA. 240 pages. ISBN: 0 674 75339 9. $24.95", "venue": "", "year": 1996 }, { "abstract": "", "author_names": [ "Paul Lester Robertson" ], "corpus_id": 154160932, "doc_id": "154160932", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Regional Advantage: Culture and Competition in Silicon Valley and Route 128 By Annalee Saxenian. Cambridge, MA: Harvard University Press, 1994. Pp. xiv, 226. $24.95.", "venue": "", "year": 1995 }, { "abstract": "Dix ans apres son livre remarque Regional advantage culture and competition in Silicon Valley and route 128 dans lequel elle comparait les cultures entrepreneuriales de ces deux regions, Annalee Saxenian, professeure d'economie regionale a Berkeley, corrige ce qui lui etait rapidement apparu comme une faiblesse de son ouvrage de 1996, c'est a dire une vision trop exclusivement americaine des districts de haute technologie. Apres une serie d'enquetes aupres d'entrepreneurs et ingenieurs.", "author_names": [ "Yves Boquet" ], "corpus_id": 160898311, "doc_id": "160898311", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Annalee Saxenian The New Argonauts, regional advantage in a global economy. Harvard University Press, 2006, 424 pages", "venue": "", "year": 2007 } ]

[ { "abstract": "De nos jours, l'architecture du reseau mobile est en pleine evolution pour assurer la montee en debit entre les Centraux (CO) (reseaux coeurs) et differents terminaux comme les mobiles, ordinateurs, tablettes afin de satisfaire les utilisateurs. Pour faire face a ces defis du futur, le reseau C RAN (Cloud ou Centralized RAN) est connu comme une solution de la 5G. Dans le contexte C RAN, toutes les BBUs (Base Band Units) sont centralisees dans le CO, seules les RRH (Remote Radio Head) restent situees a la tete de la station de base (BS) Un nouveau segment entre les BBUs et RRHs apparait nomme fronthaul Il est base sur des transmissions D ROF (digital radio overfiber) et transporte le signal radio numerique a un debit binaire eleve en utilisant le protocole CPRI (Common Public Radio Interface) En prenant en compte le CAPEX et l'OPEX, le projet ANR LAMPION a propose la technologie RSOA (Reflective Semiconductor Optical Amplifier) auto alimente afin de rendre la solution plus flexible et s'affranchir d'emetteurs/recepteurs colores dans le cadre de transmission WDM PON (Wavelength Division Multiplexing Passive Optical Network) Neanmoins, il est necessaire d'ajouter un FEC (forward error corrector) dans la transmission pour assurer la qualite de service. Donc l'objectif de cette these est de trouver le FEC le plus adequat a appliquer dans le contexte C RAN. Nos travaux se sont focalises sur l'utilisation de codes LDPC, choisis apres comparaisons des performances avec les autres types de codes. Nous avons precise les parametres (rendement du code, taille de la matrice, cycle, etc. necessaires pour les codes LDPC afin d'obtenir les meilleures performances. Les algorithmes LDPC a decisions dures ont ete choisis apres consideration du compromis entre complexites de circuit et performance. Parmi ces algorithmes a decision dures, le GDBF (gradient descent bit flipping) etait la meilleure solution. La prise en compte d'un CAN 2 Bit dans le canal nous a amene a proposer une variante le BWGDBF (Balanced weighted GDBF) Des optimisations ont egalement ete faites en regard de la convergence de l'algorithme et de la latence. Enfin, nous avons reussi a implementer notre propre algorithme sur le FPGA Spartan 6 xc6slx16. Plusieurs methodes ont ete proposees pour atteindre une latence de 5 ms souhaitee dans le contexte C RAN. Cette these a ete soutenue par le projet ANR LAMPION (Lambada based Access and Metropolitan Passive Optical networks)", "author_names": [ "Ao Li" ], "corpus_id": 171986130, "doc_id": "171986130", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Performances des codes correcteurs d'erreur LDPC appliques au lien Fronthaul optique haut debit pour l'architecture C RAN du reseau 5G conception et implantation sur FPGA", "venue": "", "year": 2017 }, { "abstract": "RESUME La livraison de marchandises est en enjeu important dans le developpement des economies actuelles (Transport Canada, 2019) La demande pour le transport de marchandises ne cesse d'augmenter et le transport routier reste le moyen de transport le plus flexible afin de satisfaire cette demande. Neanmoins, le transport routier est responsable de 20,3% des emissions de gaz a effet de serre (GES) (Statistiques Canada, 2017) et les entreprises doivent s'adapter pour maintenir leur competitivite tout en prenant en compte les externalites negatives liees a leurs operations. Ce memoire se concentre sur la planification du transport pour une societe dont une partie des operations consiste en la distribution de produits au Quebec. Le reseau de distribution de l'entreprise est compose de succursales et de clients prives. La planification proposee se base sur l'etude de scenarios operationnels bases sur differents parametres (seuil de commande des clients, quantites commandees et frequence de livraison notamment) L'ensemble de ce memoire est divise en plusieurs aspects. Le premier aspect couvert est la preparation de la base de donnees et des fichiers de traitement pour la creation des tournees. Deuxiemement, un plan d'experience complet sur 216 experiences est mis en place et les resultats obtenus sont presentes. Le plan d'experience prend en compte des parametres environnementaux (nombre de clients prives ou de succursales a livrer) et operationnels (seuil de demande, quantite a livrer ainsi que la frequence de livraison) Afin de pouvoir comparer les differents jeux de parametres, des mesures de performance sont mises en place (marge de profit liee a la livraison, quantite de GES et distance totale parcourue) Les resultats obtenus par l'analyse des resultats du plan d'experience demontrent que l'importance relative des parametres operationnels varie selon l'objectif poursuivi. Dans le cas ou le planificateur cherche a minimiser la distance parcourue par la flotte de camions, aucun des parametres operationnels etudie ne demontre d'importance significative. Cependant l'etude de la composition des instances pour lesquelles la distance est minimisee retourne un profil de client distinct (seuil de commande compris entre 1400 et 1800 notamment compose d'un equilibre en succursales et clients prives, avec des tournees de vehicules marquees par un faible kilometrage (inferieures a 200 km) mais une haute densite de livraison. Dans le cas ou l'objectif est de maximiser la marge de profit liee a la livraison, le parametre preponderant obtenu est la frequence de livraison. On retire aussi de cette analyse que les clients qui maximisent la marge de profit de l'entreprise sont majoritairement situes dans des centres urbains et qu'il est preferable que ceux ci presentent une frequence de livraison moyenne plutot que haute. En conclusion, plusieurs scenarios operationnels sont developpes afin d'aider a la prise de decisions. Le memoire se conclut sur les limitations rencontrees par les outils mis en place et la methodologie appliquee au long de cette etude. ABSTRACT Freight transportation has an important role to play in the growth of the economy (Transports Canada, 2019) Demand for freight transport continues to increase and freight transport by road remains the most flexible to satisfy this demand. Nevertheless, road transportation accounts for 20.3% of greenhouse gas (GHG) emissions (Statistics Canada, 2017) and companies must adapt to maintain their competitiveness while considering the negative externalities associated with their operations. This study focuses on transportation planning for a company whose operations include the distribution of products in the province of Quebec. The company's distribution network is composed of branches and private customers. The proposed planning is based on the study of operational scenarios based on different parameters (in particular: customer order threshold, order quantities and delivery frequency) The first aspect covered in the preparation of the database and processing files for the creation of tours. Then, a comprehensive design of experiment covering 216 experiments is implemented. The design of experiment takes into account parameters linked to the environment of the study (number of private and branch customers to deserve for example) and operational parameters (demand threshold, quantity to be delivered and delivery frequency) In order to be able to compare the different sets of parameters, some performance measures are considered, such as the total distance travelled, GHG emissions and the delivery profit margin. The results obtained by analysing the design of experiment show that the relative importance of the operational parameters varies according to the objective pursued. Where the planner seeks to minimize the distance travelled by the fleet, none of the operational parameters studied demonstrate a significant importance. However, the study of the composition of instances for which the distance is minimized yields a distinct customer profile. Branches and private clients are balanced inside the tour and those are marked a low mileage but a high delivery density. In the case for which the objective is to maximise the profit margin related to delivery, the overriding parameter obtained is the delivery frequency. This analysis also shows that customers who maximise the company's profit margin are mostly located in urban centers and that those with a medium frequency are preferable to those with a high delivery frequency. In conclusion, several operational scenarios are developed to help the decision makers. This study concludes with the limitations encountered by the different tools implemented and the methodologies applied.", "author_names": [ "Suzanne Pirie" ], "corpus_id": 226097014, "doc_id": "226097014", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Planification du transport dans un reseau hybride clients succursales", "venue": "", "year": 2020 }, { "abstract": "The energy consumption is increasing year by year due to the growth of population and the economic conditions. In order to meet the need of population and society to use electricity, the Cambodian government has established the policy to promote and encourage the development of electrification; all the villages will have electricity by the year 2020, and at least 70% of households will have access to grid quality by the year 2030. To achieve these goals, the study and development of methodology on the Low Voltage (LV) distribution system are investigated. This thesis studies the planning of LV distribution system with integration of Photovoltaic (PV) and Battery Energy Storage (BES) The first part is developed the long term planning method to tackle the challenge of load demand uncertainty in urban area; the novel algorithm was developed to search for the optimal architecture of minimizing the capital expenditure (CAPEX) and the operation expenditure (OPEX) which respects to the set of topology and electrical (current and voltage) thank to mixed integer quadratically constrained programming (MIQCP) shortest path, first fit bin packing, and Monte Carlo method. The second part is dealt with the extension of electricity coverage area with two possible solutions which are grid reinforcement and integration of PV BES for rural village; the Genetic algorithm (GA) and iterative technique were coded to search for location and sizing. The last part is concentrated on the planning of residential low voltage distribution system in both rural and urban for non electrified area thanks to the optimal architecture and PV BES integration over the planning horizon.", "author_names": [ "Vannak Vai" ], "corpus_id": 196050381, "doc_id": "196050381", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Planification du reseau de distribution basse tension avec integration de sources photovoltaiques et stockage cas du reseau du Cambodge", "venue": "", "year": 2017 }, { "abstract": "L'article aborde la notion de progression par une description de la maniere dont une enseignante planifie et met en oeuvre une sequence d'apprentissage dont les supports sont constitues de quatre albums de Geoffroy de Pennart mis en reseau. Comment envisage t elle la progression dans le choix des albums, dans les taches proposees et l'etayage apporte Comment les capacites interpretatives des eleves progressent elles Quels en sont les indicateurs, les traces visibles dans leurs discours a l'oral et a l'ecrit", "author_names": [ "Graziella Deleuze" ], "corpus_id": 214484163, "doc_id": "214484163", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Questionner la progression a travers la planification et la pratique d'une mise en reseau autour du personnage du loup", "venue": "Reperes", "year": 2019 }, { "abstract": "Cet article examine les determinants du choix du trace du reseau initial de metro de Montreal. Nous demontrons que l'integration du metro au territoire montrealais, planifiee sous la gouverne de l'administration municipale, repondit en grande partie a une volonte de faire du metro un levier de redeveloppement urbain et de proteger certaines arteres des desagrements causes par sa construction. Les tensions suscitees par cette administration intransigeante envers les municipalites voisines, de meme que les choix technologiques qu'elle effectua, contribuerent egalement a faire en sorte que le reseau initial fut presque exclusivement limite au territoire montrealais.", "author_names": [ "D Gilbert" ], "corpus_id": 145735830, "doc_id": "145735830", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Penser la mobilite, penser Montreal. La planification du trace du reseau initial de metro, 1960 1966", "venue": "", "year": 2015 }, { "abstract": "Dans le contexte de la transition energetique, il existe des inconnues liees a la fonctionnalite du reseau electrique futur avec l'augmentation de la consommation et l'introduction de nouvelles formes de production. L'adaptation du systeme actuel est inevitable, neanmoins, les solutions efficaces sont difficiles a definir. Les strategies actuelles de la planification du reseau de distribution ne repondent pas precisement aux problematiques des nouvelles productions decentralisees, le changement du profil de la consommation, l'automation du reseau de distribution avec de nouvelles strategies de gestion du reseau ainsi que la dereglementation du marche de l'electricite. De plus, la visibilite et la controlabilite du reseau de distribution est limite, l'implementation d'une gestion active optimale n'est pas a present une realite. L'evaluation du reseau intelligent est critique pour comparer aux solutions traditionnelles.L'objectif principal de cette these est d'explorer les barrieres technico economiques pour l'integration massive des energies renouvelables sur le reseau de distribution. Cette these explore plusieurs solutions au travers d'algorithmes d'optimisation de type flux de puissance qui utilisent des relaxations convexes. Pour le cas du reseau electrique basse tension, des systemes triphases desequilibres sont consideres. Pour analyser les incertitudes associees avec la generation et la demande, des algorithmes stochastiques sont abordes. Ces outils sont utilises pour i) l'optimisation de l'emplacement et le dimensionnement des batteries, ii) l'optimisation des strategies de gestion de la demande, iii) l'evaluation des strategies d'operation de flexibilite du reseau centralise et aussi decentralise et iv) etudier l'impact de differents scenarios de penetration des energies renouvelables sur les reseaux existants.", "author_names": [ "Etta Grover silva" ], "corpus_id": 149337854, "doc_id": "149337854", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optimisation de la planification et l'operation du reseau de distribution dans le contexte d'une forte penetration des energies renouvelables", "venue": "", "year": 2017 }, { "abstract": "La concurrence dans le marche des telecommunications mobiles devient de plus en plus agressive et les operateurs doivent faire face a cette rivalite en reduisant au maximum le cout a deployer dans le reseau tout en assurant les demandes en trafic et en couverture des utilisateurs qui ne cessent d'augmenter. Au debut de la vie d'un reseau mobile, la partie radio coute trop chere comparee a la partie reseau, mais au fur et a mesure que le reseau s'elargie, la partie reseau devient aussi couteuse et donc elle doit faire sujet a une planification des le depart. Ce projet de fin d'etude s'interesse a la planification de la partie fixe du reseau GSM (Le NSS) et suggere la resolution du probleme de localisation des sites d'installation des BSCs et MSCs. Apres une formulation de ce probleme, il s'avere qu'il ne peut pas etre resolu avec des methodes exactes, ce qui oblige l'utilisation de l'une des methodes qui donne des solutions proches de l'optimale, la methode choisie est Recherche Tabou qui est simple a mettre en oeuvre et permet essentiellement d'echapper du probleme des minimums locaux. Ce probleme est implante dans une application Java qui permet d'afficher graphiquement une architecture globale du reseau apres la saisie des donnees d'entrees qui sont collectees lors de la planification de la partie radio. Pour introduire le sujet, le lecteur trouvera dans le premier chapitre une breve description de l'architecture du reseau GSM et de ces composants. Le deuxieme chapitre discutera les etapes de planification d'un reseau cellulaire parmi lesquelles on trouve celle du reseau fixe. Le troisieme chapitre sera consacre a la description et a la formulation des differentes problematiques qui se posent lors de la planification du reseau fixe. Et avant de se lancer dans le chapitre cinq qui explique les differents modules utilises dans l'application, le chapitre quatre explique le principe de quelques methodes heuristiques utilisees pour la resolution des problemes tel que celui etudie dans ce travail.", "author_names": [ "Mohamed Raafat Omri" ], "corpus_id": 161545172, "doc_id": "161545172", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Developpement d'un Outil d'Aide A la Planification du Reseau Coeur GSM", "venue": "", "year": 2011 }, { "abstract": "Nous traitons du probleme de planification du pompage dans un reseau d'eau branche, muni d'une station de pompage a la source permettant d'elever l'eau a des chateaux d'eau geographiquement distribues. Cette topologie est caracteristique, en particulier mais pas exclusivement, des reseaux de distribution d'eau potable en zone rurale.Le stockage (de l'eau et de l'energie) au niveau des chateaux d'eau permet de decoupler dans le temps l'activation des pompes (pour remplir les chateaux d'eau) de la consommation d'eau (acheminee ensuite par des reseaux gravitaires jusqu'aux clients) Ce decouplage permet de degager un gain operationnel financier important en decalant le pompage quand le tarif de l'electricite est au plus bas, typiquement durant les heures creuses. Le Pump Scheduling Problem consiste a determiner un plan journalier d'allumage des pompes a moindre cout etant donnes des profils variables de demande en eau et du tarif electrique. Il est generalement formule comme un programme non convexe en nombres entiers [2] Nous proposons d'exploiter les specificites du type de reseaux considere (pompes centralisees, graphe sans circuit et sans flot sortant aux jonctions internes, valve de reduction de debit a chaque chateau d'eau) pour deriver une relaxation quadratique convexe et une heuristique de reconstruction de solutions realisables, optimales sous conditions, a partir des solutions relachees.", "author_names": [ "Gratien Bonvin", "Sophie Demassey" ], "corpus_id": 171765010, "doc_id": "171765010", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Relaxation convexe pour la planification du pompage dans un reseau branche de distribution d'eau", "venue": "", "year": 2016 }, { "abstract": "Le developpement massif des energies renouvelables intermittentes dans les systemes de puissance affecte le fonctionnement des systemes electriques. En raison des techniques limitees et des investissements necessaires pour maintenir le niveau de securite electrique actuel, les questions liees a l'envoi, a la stabilite statique et dynamique pourraient arreter le developpement de ces sources. Le sujet de la these est de developper un outil pour mesurer l'incertitude sur la disponibilite de la puissance produite par les generateurs photovoltaiques dans un reseau urbain. Premierement, l'incertitude est modelisee par l'etude de la nature incertaine de la PV energie production et de la charge. Avec les methodes stochastiques, on calcule la reserve de puissance (OR) un jour d'avance en tenant compte d'un indice de risque de fiabilite associe. Ensuite, l'OR est distribue en differents generateurs (generateurs photovoltaiques actifs et micro turbines a gaz) Afin de minimiser le cout operationnel total et/ou les emissions equivalentes de CO2, une planification optimale et une repartition quotidienne de l'OR dans differents generateurs d'energie sont mises en oeuvre. Enfin, un logiciel libre <Un systeme de gestion de l'energie convivial et un superviseur de la planification operationnelle> est developpe a partir de l'interface utilisateur graphique de Matlab pour conceptualiser le fonctionnement global du systeme.", "author_names": [ "Xingyu Yan" ], "corpus_id": 116374030, "doc_id": "116374030", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Gestion energetique sous incertitude Application a la planification et a l'allocation de reserve dans un micro reseau electrique urbain comportant des generateurs photovoltaiques actifs et du stockage", "venue": "", "year": 2017 }, { "abstract": "Le deploiement des femto cellules dans les systemes de cinquieme generation (5G) s'avere necessaire grace a leurs avantages en termes du nombre d'utilisateurs supporte, et de la reduction de la consommation d'energie, permettant ainsi de repondre aux exigences des reseaux 5G. Or que l'allocation des ressources et la gestion du traffic, tout en maintenant la qualite de service (QoS) constituent un defi majeur en terme d'equite et de debit percu au niveau du terminal. Dans ce papier, un certain nombre d'algorithmes d'ordonnancement prevus d'etre utilises en 5G, a savoir l'algorithme Proportional Fair (PF) l'algorithme Exponential Proportional Fair (EXP/PF) et l'algorithme Maximum Largest Weighted Delay First (MLWDF) sont etudies et compares en matiere d'equite (Fairness Index) de debit utile (Goodput) et d'efficacite spectrale, au niveau des femto cellules en sens descendant", "author_names": [ "Asmae Mamane", "Mohamed Elghazi", "Said Mazer", "Mohammed Fattah" ], "corpus_id": 164256778, "doc_id": "164256778", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Etude de l'impact de differents algorithmes d'ordonnancement pour les femto cellules pour des trafics temps reel dans le reseau 5G", "venue": "", "year": 2018 } ]

[ { "abstract": "One of the major developments in high density electronic packaging assembly processes is the capability of handling very thin semiconductor devices. In order to achieve high production yield in the assembly processes and high reliability for the final packages, careful study on the handling method of very thin dice is therefore needed. In this article, we focus on the die detachment process of very thin dice in the die bonding process. Both 2D and 3D finite element models are built to simulate the die detachment process of a thin die, which is adhered to a plastic adhesive film. We report the stress distribution of the die when it is subjected to a displacement load by multiple push up pins.", "author_names": [ "Arthur C M Chong", "Y M Cheung" ], "corpus_id": 6102383, "doc_id": "6102383", "n_citations": 14, "n_key_citations": 1, "score": 1, "title": "Finite element stress analysis of thin die detachment process", "venue": "Fifth International Conference onElectronic Packaging Technology Proceedings, 2003. ICEPT2003.", "year": 2003 }, { "abstract": "Abstract The presented work focuses on numerical modelling and analysis of the forming process of a thin circular disc of negligible thickness, that is later subjected to vibration induced loading and unloading cycles (fatigue) during application. During the forming process, the material of the pre form (Mild Carbon Steel, AISI 1075) is shaped into the required profile of the disc, using a fast moving punch that impacts on a die underneath. The profile consists of a hole at the center of the disc and predefined surface gradations along the periphery. This punching process is followed by heat treatment to relax the residual stresses developed. This paper discusses the development of a detailed thermo mechanical coupled model using the finite element method, to simulate the different stages of the forming process; namely, the punching process, the instantaneous punch release and structural creep, and the subsequent heat treatment to induce stress relaxation. The numerical model is intended to predict the amount of residual stress and equivalent plastic strain that are developed in the disc at the end of each stage of the forming process. The stress concentration in the disc has serious implications on the subsequent cyclic loading and unloading application. The results obtained from standard tests indicate initiation and propagation of cracks in the disc during application. The intensity and occurrence of crack initiation have a direct connection to the maximum residual stress developed in the disc during the forming process. In addition, the heat treatment model is also intended to investigate the temperature distribution in the disc, during the heating and the subsequent cooling operations. The results of the finite element model are then validated with experimental measurements for each of the stages of the forming process. The finite element packages, Abaqus/Explicit and Abaqus/Standard, are used in conjunction for the aforesaid modeling", "author_names": [ "", "Rojin Mathews", "Anoop Pillai A", "Unnikrishnan Divakaran" ], "corpus_id": 218926768, "doc_id": "218926768", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Finite Element Modeling of a Thin Circular Disc Manufactured by Forming Process used in Cyclic Loading and Unloading Applications", "venue": "", "year": 2020 }, { "abstract": "The finite element model of thin wall taper workpiece in spining was established by software ANSYS10.0,its forming process on the base of explicit dynamics optimizer LS DYNA,the deformation and stress feature in the forming process was analyzed,the influence factors of stress and strain on the work piece forming quality were studied.The results show that the stress and strain nephogram indicates the respective features in the forming process,and provides the foundation for solving the problems in the forming process.The simulation can easily find the faults and reasons of break,flanging,fold and unstability etc in the spinning.The spinning stress surging and the excessive reducing rate of wall are the most important factors that result in break.By optimizing the process parameters such as reducing rate of wall,rotating speed and load,the taper work piece forming quality can be effectively controlled.The analyzing results can provide reliable theoretical basis for the spinning die's design and parameters' choice.", "author_names": [ "Wu Zhenting" ], "corpus_id": 113239765, "doc_id": "113239765", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Finite Element Analysis of Stress and Strain Field in Thin wall Taper Workpiece During Spinning Forming", "venue": "", "year": 2011 }, { "abstract": "Ti 6Al 4V is widely utilized to manufacture airframe component structures with curvature, because of its excellent strength to weight ratio, outstanding resistance to corrosion, and inherent thermal and electrical compatibility with carbon fiber composite. Hot stretch bending (HSB) is an effective technology to manufacture these kinds of structures. When comparing the thin walled extrusion with the thick walled one, however, it is more difficult to form. The reason is that the local temperature of extrusion decreases more because of the heat transfer between extrusion and die. In this study, the material properties of Ti 6Al 4V were measured experimentally, such as the tensile property within the temperatures from 873 to 1023 K and the strain rates from 0.0005 to 0.005 s 1, the stress relaxation behavior in a wide range of temperatures (773 973 K) and prestrains (0.7 10% as well as the heat transfer rule between Ti 6Al 4V (extrusion material) and asbestos cement (die material) under different pressures (8 25 MPa) The heat transfer coefficients (HTCs) were determined by an inverse analysis procedure, which was based on the comparison between measured and calculated temperature. Then, the coupled thermomechanical finite element (FE) model considering the effect of heat transfer was established. The influence of preheating temperature of die, initial temperature of extrusion, and dwell time on spring back was researched based on orthogonal array testing strategy (OATS) The optimized parameters were verified by process test. It was showed that the established FE model could be used to predict spring back within a relative deviation of 8.05%", "author_names": [ "Gui-qiang Guo", "Dongsheng Li", "Xiao-qiang Li", "Tongsheng Deng", "Shuo Wang" ], "corpus_id": 114458457, "doc_id": "114458457", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Finite element simulation and process optimization for hot stretch bending of Ti 6Al 4V thin walled extrusion", "venue": "", "year": 2017 }, { "abstract": "Wafers warp. It is important to minimize warpage in order to achieve optimal die yield and potentially prevent future device failure. Although the word warpage is widely used in the literature to represent wafer bow (convex or concave shape) in the real world wafers are often seen into warp into saddle shapes. This complicates the characterization of both the sources of and solutions to warpage, because (as will be discussed) Stoney's formula (relating intrinsic stress and curvature) does not apply for structures warped with compound curvature, and standard wafer warpage measurements are not designed to measure compound curvature. During thin film deposition, wafer warpage occurs due to the intrinsic stresses and the coefficient of thermal expansion (CTE) mismatch of the different thin films and the substrate. Unfortunately, whereas the introduction of the thermal stresses due to CTE mismatch into a finite element model is easily understood, the introduction of intrinsic stress is not. Further, although", "author_names": [ "Aditi Mallik", "Roger Stout" ], "corpus_id": 15724575, "doc_id": "15724575", "n_citations": 10, "n_key_citations": 1, "score": 0, "title": "Simulation of Process Stress Induced Warpage of Silicon Wafers Using ANSYS(r) Finite Element Analysis", "venue": "", "year": 2010 }, { "abstract": "Incremental sheet metal forming process is a new procedure that forms three dimensional parts of metal in a thin sheet. In particular, single point incremental forming of sheet metal is considered as a process that forms products without using complex dies and specific forming tool. Through this process, a cylindrical rotating punch with hemispherical end shape follows a predefined continuous or discontinuous trajectory to deform the sheet plastically. This fabrication method is known for its flexibility and the adaptation to complex geometrical shapes [6] In the present work, the single point incremental forming process (SPIF) has been investigated experimentally and numerically using 3D finite element analysis (FEA) Regarding concerns of the material, the sheets were produced from aluminum alloy. This study focuses on using numerical simulations as a tool to predict and control some mechanical and geometrical responses. In order to understand the effect choice of model constitutive laws, we intend to compare between two relationships of stress strain hardening behavior, implemented on ABAQUS software, with the experimental results. Based on the obtained findings, a comparison study was presented in this paper between experimental and numerical results. Different outputs responses were extracted such as global geometry (springback error, shape and final achieved section profiles) and thickness distribution. Therefore, the results obtained from the simulation were validated experimentally and good correlations are found, also the process strategies show good agreement with the experiments. Simultaneously, we conclude the most efficient hardening behavior of the material that insures the obtaining of results that are as close as possible to the experimental ones.", "author_names": [ "Asma Ben Khalfallah", "Slim Ben Elechi", "Riadh Bahloul" ], "corpus_id": 214548487, "doc_id": "214548487", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Experimental Investigation and Finite Element Modeling on Incremental Forming Process of Aluminum Sheet Alloys", "venue": "", "year": 2019 }, { "abstract": "In this study, a design guideline for the die cavity and die bearing length distribution is proposed during an extrusion process of an asymmetrical thin sheet, such as clips of cell phones. The plastic flow pattern of the billet inside the die cavity is analyzed using a commercial finite element package \"DEFORM 3D\" The Module of Die Stress Analysis in the finite element software \"DEFORM 3D\" is also used to simulate the stress, strain, and the displacement distributions of the die during extrusion of clips of cell phones. The extrusion load, the stress and strain distributions of the die, the temperature distribution, and thickness distribution of the extruded product are investigated. Furthermore, hot extrusion experiments using A6061 as the specimen are executed. The experimental results of temperature, thickness distribution of the product, extrusion force, etc, are compared with the analytical values to verify the validity of the proposed die design guideline.", "author_names": [ "Y M Hwang" ], "corpus_id": 55241714, "doc_id": "55241714", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Finite Element Analysis of Hot Aluminum Extrusion of Asymmetric Parts", "venue": "", "year": 2015 }, { "abstract": "Slacked multi chip package (MCP) has been an increasingly important approach for realizing high density 3D packaging. To accommodate multiple chips within a standard package height with adequate integrity and reliability puts stringent demands on wafer thinning technology, as well as on assembly process technology. In this work, internal stress distribution and package warpage in MCP originated from process thermal load have been systematically investigated as functions of all structure parameters by finite element analysis (FEA) and Taguchi design of experiments (DOE) It is found that top die is the easiest to crack under thermal stress. The maximum stress in this die can be effectively relieved by increasing its thickness and/or by decreasing the thickness of die attach underneath. Shear stress at each interface depends negatively on the corresponding die attach thickness, while top surface warpage can be controlled by mould compound thickness above top die.", "author_names": [ "Biao Liu", "Mingxiang Wang", "Tim Fai Lam" ], "corpus_id": 23920260, "doc_id": "23920260", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Finite element stress analysis of an multi chip package by Taguchi design of experiments for package component thicknesses", "venue": "Proceedings. 7th International Conference on Solid State and Integrated Circuits Technology, 2004.", "year": 2004 }, { "abstract": "The cold expanding diameter process was simulated by the software of DEFORM. The finite element model of tube and dies were built. The object position definition, the inter object setting, movement definition and simulation step were correctly set. The deformation, total velocity distribution and equivalent stress distribution were predicted. The numerical simulation results showed that the finite element analysis could exactly describe the plastic deformation and stress distribution during the forming process.", "author_names": [ "Wei Hua Kuang" ], "corpus_id": 136635391, "doc_id": "136635391", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Finite Element Analysis of Cold Expanding of Hollow Thin Wall Tube", "venue": "", "year": 2011 }, { "abstract": "In molding process, there is a step to release molded package blocks from the moulds by ejection pins. Silicon die crack failures might occur in some kind of thin small outline package (TSOP) in this mould release step. In this work, mould release process for a TSOP product is simulated by finite element method to clarify the mechanism of silicon die crack failures. Our analysis demonstrates that some adhesion area by organic contamination on mould inner surface, during mould release step, may impede package block to be released smoothly from the mould, leading to locally built internal stress within silicon and causing die crack failures. Die crack risks with adhesion area in different size, shape and position are compared and high risk conditions are defined. Die crack failure can be reduced in packages using high elastic molding compound (MC)", "author_names": [ "Zhenyu Yang", "Mingxiang Wang", "Huaping Xu" ], "corpus_id": 35781592, "doc_id": "35781592", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Finite Element Analysis of TSOP Silicon Die Crack Issue during Molding Process", "venue": "2006 7th International Conference on Electronic Packaging Technology", "year": 2006 } ]

[ { "abstract": "The development of a high performance semiconductor oxide sensor for the accurate detection of trace disease biomarkers in exhaled breath is still a challenge that urgently needs to be addressed. Here, we proposed a self assembly strategy and spin coating process to create a graphene quantum dot (GQD) functionalized three dimensional ordered macroporous (3DOM) ZnO structure. The strong synergistic effect and the p n heterojunction between the p type GQDs and n type ZnO effectively enlarged the resistance variation due to the change in oxygen adsorption. The specific 3DOM structure induced a hierarchical pore size (286 nm in macroscale and 26 nm in mesoscale) and 3D interconnection, which guaranteed high gas accessibility and fast carrier transportation. As a result, the GQD modified 3DOM ZnO sensor exhibited a remarkably high response (Rair/Rgas 15.2 for 1 ppm acetone) rapid response/recovery time (9/16 s) extremely low theoretical detection limit (8.7 ppb) and good selectivity towards acetone against other interfering gases. In particular, the proposed sensor could accurately distinguish trace acetone in the simulated breath of diabetic patients. These results demonstrate a high potential for the feasibility of the GQD modified 3DOM SMO structure as a new sensing material for the possibility of noninvasive real time diagnosis of diabetes.", "author_names": [ "Wei-li Liu", "Xiangyu Zhou", "Lin Xu", "Shidong Zhu", "Shuo-Wang Yang", "Xinfu Chen", "Biao Dong", "Xue Bai", "Geyu Lu", "Hongwei Song" ], "corpus_id": 206143857, "doc_id": "206143857", "n_citations": 34, "n_key_citations": 0, "score": 1, "title": "Graphene quantum dot functionalized three dimensional ordered mesoporous ZnO for acetone detection toward diagnosis of diabetes.", "venue": "Nanoscale", "year": 2019 }, { "abstract": "Abstract Three dimensional (3D) long range well ordered macroporous SiCN ceramics were prepared by infiltrating sacrificial colloidal silica templates with the low molecular weight preceramic polymer, polysilazane. This was followed by a thermal curing step, pyrolysis at 1250 degC in a N2 atmosphere, and finally the removal of the templates by etching with dilute HF. The produced macroporous SiCN ceramics showed high BET surface areas (pore volume) in the range 455 m2/g (0.31 cm3/g) 250 m2/g (0.16 cm3/g) with the pore sizes of 98 578 nm, which could be tailored by controlling the sizes of the sacrificial silica spheres in the range 112 650 nm. The sphere inversed macropores were interconnected by 50 30 nm windows and 3 5 nm mesopores embedded in the porous SiCN ceramic frameworks, which resulted in a trimodal pore size distribution. The surface of the achieved porous SiCN ceramic was then modified by Pt Ru nanoparticle depositing under mild chemical conditions.", "author_names": [ "Hao Wang", "Shuang-yang Zheng", "Xiaodong Li", "Dong-Pyo Kim" ], "corpus_id": 97724347, "doc_id": "97724347", "n_citations": 33, "n_key_citations": 0, "score": 1, "title": "Preparation of three dimensional ordered macroporous SiCN ceramic using sacrificing template method", "venue": "", "year": 2005 }, { "abstract": "Abstract A series of phosphotungstic acid (HPW)/TiO2 materials with three dimensional continuous and ordered macroporous structure, ranging from 130 nm to 300 nm in size, are synthesized by colloidal crystal templates and used as catalysts for oxidative desulfurization (ODS) of model oil. The structure and properties of 3DOM HPW/TiO2 catalysts are characterized by powder X ray diffraction (XRD) scanning electron microscope (SEM) transmission electron microscopy (TEM) N2 adsorption desorption isotherms, inductively coupled plasma optical emission spectrophotometer (ICP) and fourier transform infrared spectra (FT IR) Characterization results demonstrate that all the HPW/TiO2 samples possess a large BET surface area and three dimensional ordered macroporous structure with Keggin type HPW dispersed homogeneously in TiO2 framework. 3DOM HPW/TiO2 with an average pore diameter around 250 nm presents the highest catalytic activity for dibenzothiophene (DBT) which can be attributed to the combination of its large enough macropores allowing for efficient mass transport and its high surface area enabling sufficient exposure of catalytic active sites. Furthermore, the catalyst is recovered and reused for seven runs with no obviously decrease in catalytic activity.", "author_names": [ "Du Yue", "Jiaheng Lei", "Yang Peng", "Junsheng Li", "Xiaodi Du" ], "corpus_id": 102954992, "doc_id": "102954992", "n_citations": 32, "n_key_citations": 0, "score": 1, "title": "Three dimensional ordered phosphotungstic acid/TiO2 with superior catalytic activity for oxidative desulfurization", "venue": "", "year": 2018 }, { "abstract": "Ordered 3D interconnected macroporous Prussian blue (PB) films were electrochemically fabricated by using colloidal crystals of polystyrene beads as sacrificial templates. The prepared PB film electrodes have excellent catalytic activity towards the reduction of hydrogen peroxide. The PB structure was further used as functional interface for fabricating an enzyme based glucose sensor by using surface modification technique based on the electrostatic interactions. The resulted sensor has higher functional density, and larger surface area. The interconnected macroporous structure allows enhanced mass transport. These characteristics of the sensor enable us to detect glucose with high sensitivity. Therefore, the present 3D ordered macroporous film sensor exhibits wide linear detection range towards glucose, acceptable reproducibility and operational and storage stability. The present approach is promising for the generation of high enzyme content thin films with tailored bioactivity.", "author_names": [ "Jian-Ding Qiu", "Hongzhen Peng", "Ruping Liang", "Meng Xiong" ], "corpus_id": 97793737, "doc_id": "97793737", "n_citations": 26, "n_key_citations": 1, "score": 1, "title": "Preparation of Three Dimensional Ordered Macroporous Prussian Blue Film Electrode for Glucose Biosensor Application", "venue": "", "year": 2007 }, { "abstract": "Abstract Three dimensionally ordered macroporous (3DOM) perovskite materials have attracted the interest from researchers worldwide due to their unique macroporous structure, flexible composition, tailorable physicochemical property, high stability and biocompatibility. In particular, they were widely used in environmental field, such as photocatalysis, catalytic combustion, catalytic oxidation and sensors. In this review, the recent progresses in the synthesis of 3DOM perovskite materials and their environmental applications are summarized. The advantages and the promoting mechanisms of 3DOM perovskite materials for different applications are discussed in detail. Subsequently, the challenges and perspectives on the topic are proposed.", "author_names": [ "Chenxi Zhang" ], "corpus_id": 201229080, "doc_id": "201229080", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Three dimensionally ordered macroporous perovskite materials for environmental applications", "venue": "Chinese Journal of Catalysis", "year": 2019 }, { "abstract": "Abstract Binary metal oxides are considered as promising electrode materials due to the higher electrochemical activity than mono metal oxides. However, the poor conductivity and aggregation of binary metal oxides impede ion and electron transport kinetics, which deteriorates their electrochemical performances. Herein, we design and fabricate three dimensional ordered macroporous NiFe 2 O 4 on carbon yarn, in which a core of carbon yarn is covered with the sheath of three dimensional ordered macroporous NiFe 2 O 4 The three dimensional ordered macroporous structure is feature with abundant transportation shortcuts for electrolyte ions and excellent structural stability, thus offering great advantages for efficient fibriform supercapacitor. The fibriform supercapacitor is further assembled using two intertwined three dimensional ordered macroporous NiFe 2 O 4 carbon yarn electrodes, both of which are solidified in the KOH polyvinyl alcohol gel electrolyte. The assembled fibriform supercapacitor exhibits high specific capacitance (247 mF cm 1 at scan rate of 10 mV s 1 and robust cycling stability (96% capacitance retention after 8000 cycles) Furthermore, the fibriform supercapacitor shows substantial mechanical flexibility with minor capacitance decrease upon continuous bending cycles, and the knitted fibriform supercapacitor exhibits the excellent wearability and integration. Thus, the as prepared fibriform supercapacitor shows great promise as the energy storage unit for wearable electronics.", "author_names": [ "Peng Zhao", "Xingke Ye", "Yucan Zhu", "Hedong Jiang", "Lingling Wang", "Ziyu Yue", "Zhongquan Wan", "Chunyang Jia" ], "corpus_id": 103906032, "doc_id": "103906032", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Three dimensional ordered macroporous NiFe2O4 coated carbon yarn for knittable fibriform supercapacitor", "venue": "", "year": 2018 }, { "abstract": "Nanosized 58S bioactive glass (BG) particles were synthesized by using a three dimensional ordered macroporous carbon template (OMC) with a pore size of 400nm. The obtained 58S BG particles possessed a diameter of 300nm, narrow size distribution and uniform spherical morphology. 58S/gelatin composites were prepared and showed much better mechanical properties than pure gelatin. The narrow size distribution of the 58S particles replicated from OMC was confirmed crucial to the mechanical properties of the 58S/gelatin composite, comparing to the contrast sample prepared with polydispersed particles. The outstanding bioactivity of the 58S BG particles was confirmed by inducing the formation of carbonated hydroxyapatite on the 58S/gelatin composite surface. This work showed a successful example that OMC template could be used to synthesize particles requiring a robust reaction condition, and a particle synthesis method that could well control particle size distribution was important for preparing materials with outstanding mechanical properties.", "author_names": [ "Lijun Ji", "Wei Qiao", "Kai-Wei Huang", "Yuheng Zhang", "Huayu Wu", "Shiyong Miao", "Hongfei Liu", "Yixiang Dong", "Aiping Zhu", "Dong Qiu" ], "corpus_id": 25600793, "doc_id": "25600793", "n_citations": 21, "n_key_citations": 1, "score": 0, "title": "Synthesis of nanosized 58S bioactive glass particles by a three dimensional ordered macroporous carbon template.", "venue": "Materials science engineering. C, Materials for biological applications", "year": 2017 }, { "abstract": "Abstract Three dimensional ordered macroporous (3DOM) Er 3+ Yb 3+ co doped CeO 2 and powder samples were prepared. The phase of the 3DOM sample was confirmed by XRD, and upconversion (UC) luminescence property was investigated. The results showed that green (527 nm, 548 nm) and red (659 nm) emission bands were observed in the 3DOM and powder samples under a 980 nm excitation at room temperature. It is interesting that the relative intensity of the red to green emission in the 3DOM sample increased in comparison with that of powder sample due to the increased non radiative relaxation from 4 I 11/2 to 4 I 13/2 state in the 3DOM materials.", "author_names": [ "Hangjun Wu", "Zhengwen Yang", "Jiayan Liao", "Shenfeng Lai", "Jianbei Qiu", "Zhi-guo Song", "Yong Yang", "Dacheng Zhou", "Zhaoyi Yin" ], "corpus_id": 136849828, "doc_id": "136849828", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Upconversion luminescence properties of three dimensional ordered macroporous CeO2: Er3+ Yb3+", "venue": "", "year": 2014 }, { "abstract": "Abstract A novel three dimensional ordered macroporous (3DOM) Cu/Fe 3 O 4 composite film was prepared by electrodepositing ferroferric oxide (Fe 3 O 4 on the 3DOM Cu current collector. Characterizations via electron microscopies and X ray diffractions confirmed that achieved 3DOM Cu/Fe 3 O 4 composite inherited originally ordered porous structure, but has a layer of nanosized Fe 3 O 4 on the surface of the 3DOM Cu framework. The obtained 3DOM Cu/Fe 3 O 4 composite films were directly used as anodes of lithium ion batteries in the absence of conducting additives or binders. Results from electrochemical evaluations exhibited that the 3DOM Cu/Fe 3 O 4 anode could deliver a stable capacity of 800 mAh g 1 up to 400 cycles, while fast capacity degradation with 200 mAh g 1 retained after 100 cycles was observed on Fe 3 O 4 deposited on plane Cu substrate. The superior behavior of the 3DOM Cu/Fe 3 O 4 composite anode is ascribed to its unique porous structure, which provides sufficient space for large volume change of Fe 3 O 4 and greatly reduces the diffusion distance for Li ion in the active material.", "author_names": [ "Yi-Ping Tang", "Huang Zhang", "Jiquan Li", "Guangya Hou", "Hua-zhen Cao", "Lian-Kui Wu", "Guo-qu Zheng", "Qingliu Wu" ], "corpus_id": 136161548, "doc_id": "136161548", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Three dimensional ordered macroporous Cu/Fe3O4 composite as binder free anode for lithium ion batteries", "venue": "", "year": 2017 }, { "abstract": "Abstract Three dimensionally ordered macroporous (3DOM) CeO2, 3DOM Cr2O3, 3DOM xCr2O3 CeO2 (x (the weight percentage of Cr2O3) 3.5, 5.5, and 8.0 wt% and 5.5 wt% Cr2O3/3DOM CeO2 samples were prepared using the polymethyl methacrylate (PMMA) templating and incipient wetness impregnation methods, respectively. A number of techniques were used to characterize physicochemical properties of the materials, and their catalytic activities were evaluated for the oxidation of trichloroethylene (TCE) These samples possessed a good quality 3DOM structure and a surface area of 35 47 m2/g. The 3DOM 5.5Cr2O3 CeO2 sample performed the best (the temperature at TCE conversion 90% 255 degC at a space velocity of 20,000 mL/(g h) Effects of water vapor and carbon dioxide on activity of the 5.5Cr2O3 CeO2 sample were also examined. It is observed that partial deactivation induced by H2O introduction of the 5.5Cr2O3 CeO2 sample was reversible, while that induced by CO2 addition was irreversible. Based on the activity data and characterization results, it is concluded that the good catalytic activity and thermal stability of 3DOM 5.5Cr2O3 CeO2 was associated with its high adsorbed oxygen species concentration, good low temperature reducibility, and strong interaction between Cr2O3 and CeO2. We believe that the 3DOM 5.5Cr2O3 CeO2 catalyst is promising in the application for oxidative removal of chlorinated volatile organic compounds.", "author_names": [ "Xing Zhang", "Yuxi Liu", "Jiguang Deng", "Xingtian Zhao", "Kunfeng Zhang", "Jun Yang", "Zhuo Han", "Xiyun Jiang", "Hongxing Dai" ], "corpus_id": 104456323, "doc_id": "104456323", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Three dimensionally ordered macroporous Cr2O3 CeO2: High performance catalysts for the oxidative removal of trichloroethylene", "venue": "", "year": 2020 } ]

[ { "abstract": "Series connection of individual semiconductors is an effective way to achieve higher voltage switches. However, the inherent unequal dynamic voltage sharing problem needs to be solved, even when well matched gate drivers and semiconductors are used. A majority of the existing voltage balancing schemes are developed for slow switching silicon (Si) based semiconductors, and are also associated with a significant amount of additional losses in the control circuit or on the switches. In this paper, a novel method is proposed for balancing the dynamic voltages among series connected silicon carbide (SiC) MOSFETs with high dv/dt rates. The method takes advantage of a small capacitor to provide additional current to the gate of the MOSFETs at turn off, meaning the switching speed (and thus, the device voltage after turn off) is controlled. The proposed method generates negligible losses in the control circuit, and also does not significantly increase the switching losses of the semiconductors. Experimental results are provided to prove the effectiveness of the proposed voltage balancing scheme on two SiC MOSFETs inside a module connected in series. In order to do so, an active gate driver is designed embedding the active dv/dt control scheme as well as other essential functionalities needed for operation of SiC MOSFETs.", "author_names": [ "Alinaghi Marzoughi", "Rolando Burgos", "Dushan Boroyevich" ], "corpus_id": 54449015, "doc_id": "54449015", "n_citations": 49, "n_key_citations": 6, "score": 0, "title": "Active Gate Driver With dv/dt Controller for Dynamic Voltage Balancing in Series Connected SiC MOSFETs", "venue": "IEEE Transactions on Industrial Electronics", "year": 2019 }, { "abstract": "Using high voltage (HV) silicon carbide (SiC) power semiconductors in a modular multilevel converter (MMC) is promising because it results in fewer submodules and lower switching loss compared to conventional Si based solutions. The nearest level pulsewidth modulation (NL PWM) is commonly used in the MMC for medium voltage applications. However, with the NL PWM and existing voltage balancing control, there are many submodules that switch their modes in a control cycle, resulting in a high dv/dt during the deadtime of the power semiconductor, which could be multiple times of the dv/dt of the single device. This poses great challenges on the noise immunity and insulation design in the MMC using HV SiC devices, which have very fast switching speed. A novel voltage balancing control, which ensures only two submodules switch their modes in a control cycle, is proposed in this article, limiting the maximum dv/dt to the dv/dt of a single power semiconductor and also maintaining the voltage balance performance. The proposed voltage balancing control is experimentally validated in a 10 kV SiC mosfet based MMC with four submodules per arm.", "author_names": [ "Shiqi Ji", "Li Zhang", "Xingxuan Huang", "James Palmer", "Fred Wang", "Leon M Tolbert" ], "corpus_id": 218777111, "doc_id": "218777111", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "A Novel Voltage Balancing Control With dv/dt Reduction for 10 kV SiC MOSFET Based Medium Voltage Modular Multilevel Converter", "venue": "IEEE Transactions on Power Electronics", "year": 2020 }, { "abstract": "Advanced high voltage (3.3 15kV) SiC MOSFETs have been developed for future medium voltage converters over the past decade due to their superior performance. In order to better understand the operation limits and potential of these devices, this paper evaluates the Imax fsw dv/dt trade off (maximal current handling capability at a specific switching frequency and at a defined switching speed) for high voltage SiC MOSFETs based on a proposed linearized analytical switching loss model. There, high voltage SiC MOSFETs manufactured by Cree combined with data from literature for scaling are used as reference.", "author_names": [ "Anliang Hu", "Jurgen Biela" ], "corpus_id": 222219476, "doc_id": "222219476", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Evaluation of the Imax fsw dv/dt Trade off of High Voltage SiC MOSFETs Based on an Analytical Switching Loss Model", "venue": "2020 22nd European Conference on Power Electronics and Applications (EPE'20 ECCE Europe)", "year": 2020 }, { "abstract": "The high frequency operation of the WBG devices such as SiC emphasizes the effect of parasitics, generating the reflected wave phenomenon and transient overvoltage on motor terminals, reducing the life time and the reliability of electric drives. In this paper the efficiency comparison of two topologies has been considered, a SiC MOSFET based two level and Si IGBT based three level T NPC inverter. The goal was to have the fair comparison, having the same output voltage capabilities and same output current THD. T NPC inverter is considered without an output filter, meeting the standard on voltage stress, while the dv/dt filter of 2L SiC based inverter is designed to meet the same specification as that of the T NPC inverter. The two inverters are considered with fastest switching and minimal losses. The efficiency comparison indicated the convenience of using SiC MOSFET based 2L inverter with an dv/dt filter for lower output power, while Si IGBT T NPC inverter shows higher efficiency for higher output power. The T NPC inverter shows the lowest cost and total volume as well. The goal was to ease the decision process and to have the clearest picture possible when comes to the judicious choice of the practitioners in the motor drive industry. Simulations were carried out by realistic dynamic models of power devices obtained from the manufacturer's experimental tests and verified both in the LTspice and PLECS simulation packages.", "author_names": [ "Jelena Loncarski", "Vito Giuseppe Monopoli", "Riccardo Leuzzi", "Pericle Zanchetta", "Francesco Cupertino" ], "corpus_id": 226293583, "doc_id": "226293583", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Efficiency, Cost and Volume Comparison of Si IGBT Based T NPC and 2 Level SiC MOSFET Based Topology With dv/dt Filter for High Speed Drives", "venue": "2020 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2020 }, { "abstract": "Medium voltage (MV) power converters using high voltage (HV) Silicon Carbide (SiC) power semiconductors result in great benefits in weight, size, efficiency and control bandwidth. However, HV SiC MOSFET based converters suffer from high dv/dt >100 V/ns) Under high dv/dt environment, sensors are easily interfered due to the power electronic device's fast switching. In this paper, the noise coupling mechanism in a submodule (SM) voltage sensor is analyzed, and the impact of SM voltage sensor noise on MMC phase leg operation is discussed. A simulation model and a 10 kV SiC MOSFET based MMC prototype with 25 kV dc link are built to validate the analysis of the impact.", "author_names": [ "Shiqi Ji", "James Palmer", "Xingxuan Huang", "Dingrui Li", "Bill Giewont", "Leon M Tolbert", "Fred Wang" ], "corpus_id": 220258617, "doc_id": "220258617", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Impact of Submodule Voltage Sensor Noise in 10 kV SiC MOSFET Modular Multilevel Converters (MMCs) under High dv/dt Environment", "venue": "2020 IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2020 }, { "abstract": "Silicon carbide (SiC) power devices are fundamentally capable of operating at a higher switching speed than their silicon (Si) counterparts. However, the ultra high voltage slew rate (dv/dt) aggravates the coupling effect between the two devices of the same phase leg, leading to significant cross talk issues. This paper reveals the driver parameters design method to suppress induced gate voltage spike and oscillation, without the penalty of increasing complexity and cost. The second order dynamic system analysis derives the mechanism of the induced voltage spike and oscillation. Experimental results captured from a double pulse platform justified the second order dynamic system analysis and spike and oscillation mechanism. Finally, the mechanism is used to guide the gate driver design of a 30kW commercial all SiC PWM rectifier.", "author_names": [ "Tiancong Shao", "Zhijun Li", "Zuoxing Wang", "Trillion Q Zheng", "Bo Huang", "Zhipeng Zhang" ], "corpus_id": 232235303, "doc_id": "232235303", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Induced Gate Source Voltage Mechanism and Gate Driver Design in All SiC PWM Rectifier with Ultra High Voltage Slew Rate (dv/dt)", "venue": "2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020 ECCE Asia)", "year": 2020 }, { "abstract": "The dV/dt values for 4H SiC Schottky type diodes with different type packages have been determined experimentally. It is determined that experimental dV/dt values for 4H SiC Schottky type diodes in metal polymeric packages (SOT 89, QFN, PQFN, TO 220) are varying in interval of 645,1103 V/ns. It is established that the dV/dt dependence on maximal amplitude of reverse voltage demonstrate nonlinear character (close to parabolic dependence) for all studied SiC Schottky type diodes in different type packages.", "author_names": [ "D A Knyginin", "S B Rybalka", "E A Kulchenkov", "Alexander A Demidov", "N A Zhemoedov", "Alexandr Y Drakin" ], "corpus_id": 234517237, "doc_id": "234517237", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "dV/dt testing of high voltage 4H SiC Schottky diodes with different types of metal polymeric packages", "venue": "", "year": 2020 }, { "abstract": "In this paper, a dv/dt filter is designed for the modular multilevel converters (MMCs) based variable frequency motor drives. This concept utilizes the inherent arm inductors of the MMC as a part of the output low pass filter, thus eliminating the need for an add on inductor. Particularly, a mathematical model is proposed to optimize the filter loss and volume for a given dv/dt requirements. It turns out that with SiC MOSFET based high switching frequency operation, the dv/dt filter improves the output power quality and alleviates the voltage stress in motor drive applications. For applications with various requirements on filter volume and loss, weighted sum optimal solutions are presented. Simulation results based on a seven level MMC are provided to validate the theoretical analysis.", "author_names": [ "Xiao Li", "Jianyu Pan", "Ziwei Ke", "Rui Ying Liu", "Junchong Fan", "Ya-li Zhang", "Boxue Hu", "Risha Na", "Longya Xu", "Jin Wang" ], "corpus_id": 226293957, "doc_id": "226293957", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optimized Dv/dt Filter Design for SiC based Modular Multilevel Converters", "venue": "2020 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2020 }, { "abstract": "A SiC JFET/GaN HEMT cascode device is recently proposed, incorporating a low voltage (LV) GaN HEMT providing normally off operation and a high voltage (HV) delivering the HV blocking capability. This cascode device exhibits superior thermal stability and switching speed compared to SiC MOSFETs, but also inevitably presents challenge in dv/dt control as the JFET's gate cannot be directly controlled by the gate drive. Since dv/dt control is of great importance to the management and suppression of electromagnetic interference (EMI) in power electronics systems, methods of controlling the dv/dt rates of SiC/GaN cascode devices need to be developed. In this work, we demonstrated a SiC/GaN cascode device in a highly compact package using flip chip co package (FCCP) structure, aiming at minimizing the parasitic influences on its performance evaluation. The dv/dt control method based on RCD control (i.e. resistor capacitor diode control) is proposed and verified through experimental results using the demonstrated FCCP cascode device. The RCD control method is verified to be more effective compared to other more conventional methods regarding to the transient behavior and gate driver losses, owing to its balanced control of the turn on/off dv/dt rates.", "author_names": [ "Gang Lyu", "Yuru Wang", "Jin Wei", "Zheyang Zheng", "Jiahui Sun", "Kevin J Chen" ], "corpus_id": 221282968, "doc_id": "221282968", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Dv/Dt control of 1200 V Co packaged SiC JFET/GaN HEMT Cascode Device", "venue": "2020 32nd International Symposium on Power Semiconductor Devices and ICs (ISPSD)", "year": 2020 }, { "abstract": "A test scheme is designed to qualify MMC submodules based on 10 kV SiC MOSFETs comprehensively, including thermal design, insulation design, and operation under high dv/dt. In the test scheme, the essential step is the continuous test realized with the proposed ac dc continuous test circuit with two MMC submodules in series. With the designed modulation scheme, two cascaded submodules are leveraged to generate high dv/dt. The submodule under test has to continuously withstand 2X normal dv/dt of 10 kV SiC MOSFETs, which could occur during the MMC converter operation. Higher dv/dt can also be generated to fully test the submodule. An open loop voltage balancing method is adopted to simplify the continuous test setup. Simulation and experimental results are provided to validate the proposed test scheme.", "author_names": [ "Xingxuan Huang", "Shiqi Ji", "Dingrui Li", "Cheng Nie", "William Giewont", "Leon M Tolbert", "Fred Wang" ], "corpus_id": 222223091, "doc_id": "222223091", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Test Scheme for the Comprehensive Qualification of MMC Submodule Based on 10 kV SiC MOSFETs under High dv/dt", "venue": "2020 22nd European Conference on Power Electronics and Applications (EPE'20 ECCE Europe)", "year": 2020 } ]

[ { "abstract": "Significance Charge transfer through organic molecules is extensively studied theoretically and experimentally owing to its importance in basic biological processes. Long distance electron transport through such molecules, which are typically insulating, is commonly attributed to thermally activated hopping. We introduce an additional mechanism that supports electron transfer across appreciable distances, even at zero temperature. It originates from the electric potential that is either internally created or externally applied before charge flows. The electronic wavefunctions are dramatically changed by this potential, allowing them to efficiently mediate current. This mechanism can explain recent experiments where electron transfer shows only a weak temperature dependence. Our result is an important contribution to the long standing challenge of developing a comprehensive theory for charge transfer through organic molecules. Biological structures rely on kinetically tuned charge transfer reactions for energy conversion, biocatalysis, and signaling as well as for oxidative damage repair. Unlike man made electrical circuitry, which uses metals and semiconductors to direct current flow, charge transfer in living systems proceeds via biomolecules that are nominally insulating. Long distance charge transport, which is observed routinely in nucleic acids, peptides, and proteins, is believed to arise from a sequence of thermally activated hopping steps. However, a growing number of experiments find limited temperature dependence for electron transfer over tens of nanometers. To account for these observations, we propose a temperature independent mechanism based on the electric potential difference that builds up along the molecule as a precursor of electron transfer. Specifically, the voltage changes the nature of the electronic states away from being sharply localized so that efficient resonant tunneling across long distances becomes possible without thermal assistance. This mechanism is general and is expected to be operative in molecules where the electronic states densely fill a wide energy window (on the scale of electronvolts) above or below the gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) We show that this effect can explain the temperature independent charge transport through DNA and the strongly voltage dependent currents that are measured through organic semiconductors and peptides.", "author_names": [ "Karen Michaeli", "David N Beratan", "David H Waldeck", "Ron Naaman" ], "corpus_id": 73507671, "doc_id": "73507671", "n_citations": 21, "n_key_citations": 1, "score": 1, "title": "Voltage induced long range coherent electron transfer through organic molecules", "venue": "Proceedings of the National Academy of Sciences", "year": 2019 }, { "abstract": "The recently discovered chiral induced spin selectivity (CISS) effect gives rise to a spin selective electron transmission through biomolecules. Here we review the mechanism behind the CISS effect and its implication for processes in Biology. Specifically, three processes are discussed: long range electron transfer, spin effects on the oxidation of water, and enantioselectivity in bio recognition events. These phenomena imply that chirality and spin may play several important roles in biology, which have not been considered so far.", "author_names": [ "Karen Michaeli", "Nirit Kantor-Uriel", "Ron Naaman", "David H Waldeck" ], "corpus_id": 10361878, "doc_id": "10361878", "n_citations": 84, "n_key_citations": 0, "score": 0, "title": "The electron's spin and molecular chirality how are they related and how do they affect life processes?", "venue": "Chemical Society reviews", "year": 2016 }, { "abstract": "Laccase from Phoma sp. UHH 5 1 03 was cross linked to polyvinylidene fluoride membranes by electron beam irradiation. Immobilised laccase displayed a higher stability than the non immobilised enzyme with respect to typical wastewater temperatures, and pH at a range of 5 to 9. Batch tests addressed the removal of pharmaceutically active compounds (PhACs; applied as a mixture of acetaminophen, bezafibrate, indometacin, ketoprofen, mefenamic acid, and naproxen) by both immobilised and non immobilised laccase in municipal wastewater. High removal rates >85% of the most efficiently oxidised PhACs (acetaminophen and mefenamic acid) indicated a high efficiency of the immobilised laccase in wastewater. Continuous elimination of the aforementioned PhACs by the immobilised enzyme in a continuously operated diffusion basket reactor yielded a PhAC removal pattern qualitatively similar to those observed in batch tests. Clearly higher apparent Vmax values and catalytic efficiencies (in terms of both Vmax/S0.5 as well as Vmax/Km values obtained from data fitting according to the Hill and the Michaelis Menten model, respectively) observed for acetaminophen oxidation by the immobilised compared to the non immobilised enzyme are in support of a considerably higher functional stability of the immobilised laccase especially in wastewater. The potential influence of acetaminophen on the removal of comparatively less laccase oxidisable water pollutants such as the antimicrobial triclosan (TCS) was investigated. TCS was increasingly removed upon increasing the initial acetaminophen concentration in immobilised as well as non immobilised laccase reaction systems until saturation became evident. Acetaminophen was consumed and not recycled during laccase reactions, which was accompanied by the formation of various acetaminophen TCS cross coupling products. Nevertheless, the simultaneous presence of acetaminophen (and potentially even more pollutant removal enhancing laccase substrates) and more recalcitrant pollutants in wastewater represents an interesting option for the efficiency enhancement of enzyme based wastewater treatment approaches.", "author_names": [ "Elham Jahangiri", "Isabell Thomas", "Agnes Schulze", "Bettina Seiwert", "Hubert Cabana", "Dietmar Schlosser" ], "corpus_id": 3428648, "doc_id": "3428648", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Characterisation of electron beam irradiation immobilised laccase for application in wastewater treatment.", "venue": "The Science of the total environment", "year": 2018 }, { "abstract": "Carbon nanotubes (CNTs) are excellent supports for electrocatalysts because of their large surface area, excellent electronic conductivity, and high chemical and structural stability. In the present study, the activity of CNTs on direct electron transfer (DET) and on immobilized glucose oxidase (GOX) is studied as a function of number of walls of CNTs. The results indicate that the GOX immobilized by the CNTs maintains its electrocatalytic activity toward glucose; however, the DET and electrocatalytic activity of GOX depend strongly on the number of inner tubes of CNTs. The GOX immobilized on triple walled CNTs (TWNTs) has the highest electron transfer rate constant, 1.22 s 1, for DET, the highest sensitivity toward glucose detection, 66.11 5.06 mA mM 1 cm 2, and the lowest apparent Michaelis Menten constant, 6.53 0.58 mM, as compared to GOX immobilized on single walled and multiwalled CNTs. The promotion effect of CNTs on the GOX electrocatalytic activity and DET is most likely due to the electron tunneling effect between the outer wall and inner tubes of TWNTs. The results of this study have general implications for the fundamental understanding of the role of CNT supports in DET processes and can be used for the better design of more effective electrocatalysts for biological processes including biofuel cells and biosensors.", "author_names": [ "Yuxiang Liu", "Jin Zhang", "Yi Cheng", "San Ping Jiang" ], "corpus_id": 49867645, "doc_id": "49867645", "n_citations": 36, "n_key_citations": 0, "score": 0, "title": "Effect of Carbon Nanotubes on Direct Electron Transfer and Electrocatalytic Activity of Immobilized Glucose Oxidase", "venue": "ACS omega", "year": 2018 }, { "abstract": "The DLR Institute of Planetary Exploration has proposed a novel design of a space instrument accommodated on a small satellite bus (SSB) that is dedicated to the detection of inner earth objects (IEOs) from a low earth orbit (LEO) The instrument design is based on a focal plane consisting of electron multiplied CCDs (EMCCD) operating at high frame rates for compensation of the spacecraft's pointing jitter at very low effective readout noise. The CCD detectors operate at a nominal operating temperature of 80degC and at a frame rate of 5fps. It is well known, that CCD detectors are prone to space radiation. However, EMCCD, designed to detect very low light levels of a few electrons, have not yet been used in space. Therefore, investigations have been initiated and performed by DLR for evaluation of the performance of EMCCDs before and after radiation. The main scope of the investigations was the characterization of the charge transfer efficiency (CTE) at low light levels because of its key impact on the detection performance. The non ionizing dose effects of space high energy particle radiation on the detector were simulated by 60MeV protons at two different fluence levels. The low light CTE was measured with point light sources without and with background light.", "author_names": [ "Harald Michaelis", "Thomas Behnke", "Stefano Mottola", "Anja Krimlowski", "Belinda Borgs", "Andrew D Holland", "Markus Schmid" ], "corpus_id": 112726530, "doc_id": "112726530", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Investigations on performance of Electron Multiplied CCD detectors (EMCCDs) after radiation for observation of low light star like objects in scientific space missions", "venue": "Remote Sensing", "year": 2013 }, { "abstract": "The response of low density polyethylene (LDPE) to high energy electron beam irradiation in air (10 MeV) between 25 and 400 kGy was examined and compared to non irradiated polyethylene in terms of the mechanical and structural properties. To quantify the degree of crosslinking, swelling studies were performed and from this it was observed that the crosslink density increased as the irradiation dose increased. Furthermore, a reduction was observed in the numerical data for molar mass between adjacent crosslinks and the number of monomeric units between adjacent crosslinks as the irradiation dose was conducted incrementally. Accelerated aging provided evidence that radicals became trapped in the polymer matrix of LDPE and this in turn initiated further reactions to transpire as time elapsed, leading to additional alteration in the structural properties. Fourier transform infrared spectroscopy (FTIR) was implemented to provide insight into this. This technique established that the aging process had increased the oxidative degradation products due to oxygen permeation into the polymer and double bonds within the material. Mechanical testing revealed an increase in the tensile strength and a decrease in the elongation at break. Accelerated aging caused additional modifications to occur in the mechanical properties which are further elucidated throughout this study. Dynamic frequency sweeps investigated the effects of irradiation on the structural properties of LDPE. The effect of varying the irradiation dose concentration was apparent as this controlled the level of crosslinking within the material. Maxwell and Kelvin or Voigt models were employed in this analytical technique to define the reaction procedure of the frequency sweep test with regards to non crosslinked and crosslinked LDPE.", "author_names": [ "Kieran A Murray", "James E Kennedy", "Brian McEvoy", "Olivier Vrain", "Damien Ryan", "Richard Cowman", "Clement L Higginbotham" ], "corpus_id": 94821737, "doc_id": "94821737", "n_citations": 44, "n_key_citations": 2, "score": 0, "title": "The effects of high energy electron beam irradiation in air on accelerated aging and on the structure property relationships of low density polyethylene", "venue": "", "year": 2013 }, { "abstract": "Thick GEM like (THGEM) gaseous electron multipliers are made of standard printed circuit board perforated with sub millimeter diameter holes, etched at their rims. Effective gas multiplication factors of 10 5 and 10 7 and fast pulses in the few nanosecond rise time scale were reached in single and cascaded double THGEM elements, in atmospheric pressure standard gas mixtures with single photoelectrons. High single electron detection efficiency is obtained in photon detectors combining THGEMs and semitransparent UVsensitive CsI photocathodes or reflective ones deposited on the top THGEM face; the latter benefits of a reduced sensitivity to ionizing background radiation. Stable operation was recorded with photoelectron fluxes exceeding MHz/mm 2 The properties and some potential applications of these simple and robust multipliers are discussed.", "author_names": [ "C Shalem", "Rachel Chechik", "Amos Breskin", "Karen Michaeli" ], "corpus_id": 19919585, "doc_id": "19919585", "n_citations": 148, "n_key_citations": 13, "score": 0, "title": "Advances in Thick GEM like gaseous electron multipliers Part I: atmospheric pressure operation", "venue": "", "year": 2006 }, { "abstract": "Abstract Radiation is currently being exploited to modify polyethylene in order to improve properties for various applications such as hip replacements. This paper thoroughly examines the effects of high energy electron beam irradiation (10 MeV) on low density polyethylene (LDPE) material. ASTM (American Society for Testing and Materials) testing specimens were manufactured from LDPE and subjected to a broad range of doses ranging between 25 and 400 kGy at room temperature in an air atmosphere. Extensive characterisation techniques such as modulated differential scanning calorimetry (MDSC) and the Fourier transform infrared spectroscopy (FTIR) were conducted on the non irradiated and irradiated samples. While considering the semicrystalline nature of LDPE during the MDSC experiment, the melting temperature T m and the temperature crystallinity T c were calculated. This revealed that the T m and the T c decreased in temperature as the irradiation dose increased. The FTIR analysis was implemented to evaluate the presence of polar species such as carbonyl groups and trans vinylene double bond groups. The IR spectra illustrated that the concentration of characteristic bands for trans vinylene bonds increased with increasing radiation dose indicating the formation of carbonyl bond groups. Furthermore, the results demonstrated an occurrence of oxidative degradation due to the formation of carbonyl groups at 1718 cm 1", "author_names": [ "Kieran A Murray", "James E Kennedy", "Brian McEvoy", "Olivier Vrain", "Damien Ryan", "Clement L Higginbotham" ], "corpus_id": 97299159, "doc_id": "97299159", "n_citations": 42, "n_key_citations": 2, "score": 0, "title": "The effects of high energy electron beam irradiation on the thermal and structural properties of low density polyethylene", "venue": "", "year": 2012 }, { "abstract": "It is well known that polyurethane (PU) provides good irradiation resistance; however, extremely high irradiation doses can alter the structure and/or function of macromolecules, resulting in oxidation, chain scission and crosslinking. In this present study, modifications to the material characteristics resulting from irradiation were extensively examined through a broad array of analytical techniques. Fourier transform infrared spectroscopy (FTIR) revealed that there were a number of changes to the chemical structure after electron beam irradiation while dynamic frequency sweeps identified an occurrence of crosslinking particularly in the higher irradiation doses. The degree of crosslinking was further analysed by implementing the crosslink density experiment, which illustrated a high level of crosslinking at 200 kGy only. X ray diffraction (XRD) and differential scanning calorimetry (DSC) identified an increase in phase segregation and as a consequence it could lead to soft segment mobility. This increase in mobility could be responsible for an increase in the degree of chain orientation. Surface morphology of the electron beam irradiated material was determined using scanning electron microscope (SEM) imagery and this provided evidence that the surface of the material had clearly transformed with the development of additional ridges. The influence of such modifications initiated a significant reduction in the contact angle at the upper irradiation dose regime. Overall, this study demonstrated that the medical grade PU was highly affected by radiation exposure, particularly at high irradiation doses.", "author_names": [ "Kieran A Murray", "James E Kennedy", "Brian McEvoy", "Olivier Vrain", "Damien Ryan", "Richard Cowman", "Clement L Higginbotham" ], "corpus_id": 135753692, "doc_id": "135753692", "n_citations": 30, "n_key_citations": 1, "score": 0, "title": "The influence of electron beam irradiation conducted in air on the thermal, chemical, structural and surface properties of medical grade polyurethane", "venue": "", "year": 2013 }, { "abstract": "The spin transfer mechanisms of three B site ordered double perovskites, Ba2YMO6 (M Mo, Re, and Ru) were determined using variable temperature 89Y and 137Ba magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. On the basis of symmetry compatible overlap and trends observed in the MAS NMR, spin polarization was determined to be the dominant mechanism at the Y sites and spin delocalization to be the operative mechanism at the Ba sites. The MAS NMR spectra display 89Y and 137Ba chemical shifts that far exceed those of other paramagnetic solids, appearing at up to 6402 and +12 200 ppm, respectively. Detection of additional resonances in 89Y MAS NMR indicates a small degree of cation site mixing in two cases.", "author_names": [ "Vladimir K Michaelis", "Brandon J Greer", "Tomoko Aharen", "John E Greedan", "Scott Kroeker" ], "corpus_id": 100637704, "doc_id": "100637704", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Determining Electron Spin Transfer Mechanisms in Paramagnetic Ba2YMO6 (M Mo, Re, Ru) Double Perovskites by 89Y and 137Ba MAS NMR Spectroscopy", "venue": "", "year": 2012 } ]

[ { "abstract": "We describe the University of Florida Sparse Matrix Collection, a large and actively growing set of sparse matrices that arise in real applications. The Collection is widely used by the numerical linear algebra community for the development and performance evaluation of sparse matrix algorithms. It allows for robust and repeatable experiments: robust because performance results with artificially generated matrices can be misleading, and repeatable because matrices are curated and made publicly available in many formats. Its matrices cover a wide spectrum of domains, include those arising from problems with underlying 2D or 3D geometry (as structural engineering, computational fluid dynamics, model reduction, electromagnetics, semiconductor devices, thermodynamics, materials, acoustics, computer graphics/vision, robotics/kinematics, and other discretizations) and those that typically do not have such geometry (optimization, circuit simulation, economic and financial modeling, theoretical and quantum chemistry, chemical process simulation, mathematics and statistics, power networks, and other networks and graphs) We provide software for accessing and managing the Collection, from MATLAB#8482; Mathematica#8482; Fortran, and C, as well as an online search capability. Graph visualization of the matrices is provided, and a new multilevel coarsening scheme is proposed to facilitate this task.", "author_names": [ "Timothy A Davis", "Yifan Hu" ], "corpus_id": 207191190, "doc_id": "207191190", "n_citations": 2886, "n_key_citations": 295, "score": 2, "title": "The university of Florida sparse matrix collection", "venue": "TOMS", "year": 2011 }, { "abstract": "The SuiteSparse Matrix Collection (formerly known as the University of Florida Sparse Matrix Collection) (Davis Hu, 2011) has grown significantly since its introduction, with newly added matrices representing almost seven times as much data than the entirety of the original Collection. With this growth, searching the Collection for matrices with specific names, structures, and other properties has become increasingly difficult. To make the Collection more accessible to the scientific computing community, we have developed a web application that allows real time search and filtering of the Collection matrices.", "author_names": [ "Scott P Kolodziej", "Mohsen Mahmoudi Aznaveh", "Matthew Bullock", "Jarrett David", "Timothy A Davis", "Matthew Henderson", "Yifan Hu", "Read Sandstrom" ], "corpus_id": 88479234, "doc_id": "88479234", "n_citations": 23, "n_key_citations": 2, "score": 0, "title": "The SuiteSparse Matrix Collection Website Interface", "venue": "J. Open Source Softw.", "year": 2019 }, { "abstract": "Intel announced to launch a Xeon with high latency main memory based on 3D Xpoint in 2018. This paper presents the performance evaluation of sparse matrix kernels on the future supercomputers with high latency main memory such as 3D Xpoint. The authors propose a high throughput evaluation methodology for exhaustive experiments, which use the University of Florida sparse matrix collection and/or LIS (a Library of Iterative Solvers for linear systems) etc. Proposed methodology is very simple to use, highly flexible for environment and high throughput. Latency sensitivity of SpMV is measured based on the proposed methodology with 208 sparse matrices and ten storage formats only in two days, which would take for about ten years by conventional simulators. We got several interesting knowledge about latency sensitive kernels, sparse matrices, storage formats, and preconditioners, etc. We observed notable latency sensitivity in some applications, which are Graph500, HPCG and a part of preconditioners of iterative solvers. We found latency sensitivities of SpMV are high for larger matrices than the capacity of last level cache. This suggests main memory using 3D Xpoint must be combined with large DRAM cache.", "author_names": [ "Noboru Tanabe", "Toshio Endo" ], "corpus_id": 46974042, "doc_id": "46974042", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Characterizing Memory Latency Sensitivity of Sparse Matrix Kernels", "venue": "2018 26th Euromicro International Conference on Parallel, Distributed and Network based Processing (PDP)", "year": 2018 }, { "abstract": "Matrix Depot is a Julia software package that provides easy access to a large and diverse collection of test matrices. Its novelty is threefold. First, it is extensible by the user, and so can be adapted to include the user's own test problems. In doing so it facilitates experimentation and makes it easier to carry out reproducible research. Second, it amalgamates in a single framework two different types of existing matrix collections, comprising parametrized test matrices (including Hansen's set of regularization test problems and Higham's Test Matrix Toolbox) and real life sparse matrix data (giving access to the University of Florida Sparse Matrix Collection) Third, it fully exploits the Julia language. It uses multiple dispatch to help provide a simple interface and, in particular, to allow matrices to be generated in any of the numeric data types supported by the language.", "author_names": [ "Weijian Zhang", "Nicholas John Higham" ], "corpus_id": 27741060, "doc_id": "27741060", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Matrix Depot: an extensible test matrix collection for Julia", "venue": "PeerJ Comput. Sci.", "year": 2016 }, { "abstract": "In this paper we present PMORSy a new parallel software package for symmetric sparse matrix ordering on shared memory systems. The NP complete fill in minimization problem is solved by means of multilevel nested dissection algorithm with modifications for vertex separators. Parallel processing is done in a task based fashion with the granularity tuning. We employ threading techniques on shared memory using OpenMP 3.0 technology as opposed to the Message Passing Interface based approach widely used for parallel sparse matrix ordering. Experimental results on symmetric matrices from the University of Florida Sparse Matrix Collection and matrices from finite element analysis of three dimensional strength problems show that our implementation is competitive to the ParMETIS and PT Scotch libraries both in ordering quality and performance. The PMORSy library is publicly available from the Lobachevsky State University Supercomputing Center web site.", "author_names": [ "Anna Pirova", "Iosif B Meyerov", "Evgeniy Kozinov", "Sergey Lebedev" ], "corpus_id": 5429894, "doc_id": "5429894", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "PMORSy: parallel sparse matrix ordering software for fill in minimization+", "venue": "Optim. Methods Softw.", "year": 2017 }, { "abstract": "Sparse matrix vector multiplication (SpMV) is an important computational kernel in many applications. For performance improvement, software libraries designated for SpMV computation have been introduced, e.g. MKL library for CPUs and cuSPARSE library for GPUs. However, the computational throughput of these libraries is far below the peak floating point performance offered by hardware platforms, because the efficiency of SpMV kernel is greatly constrained by the limited memory bandwidth and irregular data access patterns. In this work, we propose a data locality aware design framework for FPGA based SpMV acceleration. We first include the hardware constraints in sparse matrix compression at software level to regularize the memory allocation and accesses. Moreover, a distributed architecture composed of processing elements is developed to improve the computation parallelism. We implement the reconfigurable SpMV kernel on Convey HC 2ex and conduct the evaluation by using the University of Florida sparse matrix collection. The experiments demonstrate an average computational efficiency of 48.2% which is a lot better than those of CPU and GPU implementations. Our FPGA based kernel has a comparable runtime as GPU, and achieves 2.1x reduction than CPU. Moreover, our design obtains substantial saving in energy consumption, say, 9.3x and 5.6x better than the implementations on CPU and GPU, respectively.", "author_names": [ "Sicheng Li", "Yandan Wang", "Wujie Wen", "Yu Wang", "Yiran Chen", "Hai Helen Li" ], "corpus_id": 14350325, "doc_id": "14350325", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "A data locality aware design framework for reconfigurable sparse matrix vector multiplication kernel", "venue": "2016 IEEE/ACM International Conference on Computer Aided Design (ICCAD)", "year": 2016 }, { "abstract": "Many recent studies suggest that energy efficiency should be placed as a primary design goal on par with the performance in building both the hardware and the software. As a primary step toward finding a good compromise between these two conflicting design goals, first we need to have a deep understanding about the performance and the energy of different application kernels. In this paper, we focus on evaluating the energy efficiency of the Sparse Matrix Vector Multiplication (SpMV) a very challenging kernel given its irregular aspect both in terms of memory access and control flow. In the present work, we consider the SpMV kernel under four different sparse formats (COO, CSR, ELL, and HYB) on GPU. Our experimental results obtained by using real world sparse matrices from the University of Florida collection on an NVIDIA Maxwell GPU (GTX 980Ti) show that there is no universal best sparse format in terms of energy efficiency. Furthermore, we identified some sparsity characteristics which are related to the energy efficiency of different sparse formats.", "author_names": [ "Akrem Benatia", "Weixing Ji", "Yizhuo Wang", "Feng Shi" ], "corpus_id": 1465965, "doc_id": "1465965", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Energy evaluation of Sparse Matrix Vector Multiplication on GPU", "venue": "2016 Seventh International Green and Sustainable Computing Conference (IGSC)", "year": 2016 }, { "abstract": "It is well known that the sparse matrix vector product Ax requires two floating point operations per each non zero element in A. However, when computing the number of flops for the symmetric sparse matrix vector product (Sym SpMV) some subtleties should be considered because the number of non zero (nnz) elements reported on symmetric sparse matrices varies from one research work to another. In general, matrices are chosen from the University of Florida Sparse Matrix Collection and for symmetric matrices, in this collection, the nnz elements in the profile differs from the nnz elements stored in file. Therefore, we can find two different works using similar algorithms and reporting different nnz elements for the same matrix because one uses the nnz elements found in the matrix profile and the other reports the nnz elements in store (the lower triangular matrix) which is misleading. If symmetry is exploited, computing four floating point operations per each off diagonal non zero element is correct in a symmetric matrix but it is not accurate to count four floating point operations on diagonal non zero coefficients because they only produce one or two floating point operations per nonzero element depending on the handling of the diagonal. Furthermore, there are symmetric matrices whose diagonal is not dense or all elements are zero. We evaluate three algorithms proposed in the literature to compute the symmetric SpMV and observe their behavior on a small set of different symmetric sparse matrix types. Based on our experimental results we propose a more accurate way to measure flops when dealing with the symmetric sparse matrix vector product. Finally, we show that an algorithm can run faster than another and produce less flops than the slower one.", "author_names": [ "Euripides Montagne", "Edward Aymerich" ], "corpus_id": 8612661, "doc_id": "8612661", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Let's agree on computing flops for the symmetric sparse matrix vector product", "venue": "SpringSim", "year": 2016 }, { "abstract": "The sparse matrix partitioning problem arises when minimizing communication in parallel sparse matrix vector multiplications. Since the problem is NP hard, heuristics are usually employed to find solutions. Here, we present a purely combinatorial branch and bound method for computing optimal bipartitionings of sparse matrices, in the sense that they have the lowest communication volume out of all possible bipartitionings obeying a certain load balance constraint. The method is based on a way of partitioning similar to the recently proposed medium grain heuristic, which reduces the number of solutions to be considered in the branch and bound method.We applied the proposed optimal bipartitioner to find the optimal communication volume of all matrices of the University of Florida sparse matrix collection with 1000 nonzeros or less. For 85% of the matrices, an optimal bipartitioning was found within a single day of computation and for 58% even within a second. We also present optimal results for selected larger matrices, up to 129,042 nonzeros. The optimal bipartitionings and corresponding communication volumes are made publicly available in a benchmark collection. We present an exact branch and bound algorithm for sparse matrix bipartitioning.Rows and columns are partitioned instead of nonzeros to reduce computation time.For 85% of a test set of small matrices, an optimal bipartitioning was found.The largest matrix that was optimally bipartitioned has 129,042 nonzeros.A benchmark collection of optimal results will be made publicly available.", "author_names": [ "Daniel Maria Pelt", "Rob H Bisseling" ], "corpus_id": 18060313, "doc_id": "18060313", "n_citations": 7, "n_key_citations": 3, "score": 0, "title": "An exact algorithm for sparse matrix bipartitioning", "venue": "J. Parallel Distributed Comput.", "year": 2015 }, { "abstract": "Sparse Matrix Matrix multiplication (SpMM) is a fundamental operation over irregular data, which is widely used in graph algorithms, such as finding minimum spanning trees and shortest paths. In this work, we present a hybrid CPU and GPU based parallel SpMM algorithm to improve the performance of SpMM. First, we improve data locality by element wise multiplication. Second, we utilize the ordered property of row indices for partial sorting instead of full sorting of all triples according to row and column indices. Finally, through a hybrid CPUGPU approach using two level pipelining technique, our algorithm is able to better exploit a heterogeneous system. Compared with the state of the art SpMM methods in cuSPARSE and CUSP libraries, our approach achieves an average of 1.6x and 2.9x speedup separately on the nine representative matrices from University of Florida sparse matrix collection. INDEX WORDS: Sparse matrix matrix multiplication, Data locality, Pipelining, GPU OPTIMIZING SPARSE MATRIX MATRIX MULTIPLICATION ON A HETEROGENEOUS CPU GPU PLATFORM", "author_names": [ "Xiaolong Wu" ], "corpus_id": 7246908, "doc_id": "7246908", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optimizing Sparse Matrix Matrix Multiplication on a Heterogeneous CPU GPU Platform", "venue": "", "year": 2015 } ]

[ { "abstract": "Strong perovskite interfaces The weak bonding in the crystal lattice of hybrid perovskites used in solar cells promotes surface decomposition and interferes with the formation of stable heterostructures with the charge carrier layers. Y. Wang et al. show that strong bonds are formed between lead and both chlorine and oxygen atoms in a film with a lead rich surface and a chlorinated graphene oxide layer. This interface was used with common hole transporting materials to fabricate solar cells that maintained 90% of their initial efficiency of 21% after operation at 60degC for 1000 hours. Science, this issue p. 687 Chlorinated graphene oxide forms a stable interface with hybrid perovskites that have a lead rich surface. Here we report a solution processing strategy to stabilize the perovskite based heterostructure. Strong Pb Cl and Pb O bonds formed between a [CH(NH2)2]x[CH3NH3]1 xPb1+yI3 film with a Pb rich surface and a chlorinated graphene oxide layer. The constructed heterostructure can selectively extract photogenerated charge carriers and impede the loss of decomposed components from soft perovskites, thereby reducing damage to the organic charge transporting semiconductors. Perovskite solar cells with an aperture area of 1.02 square centimeters maintained 90% of their initial efficiency of 21% after operation at the maximum power point under AM1.5G solar light (100 milliwatts per square centimeter) at 60degC for 1000 hours. The stabilized output efficiency of the aged device was further certified by an accredited test center.", "author_names": [ "Yanbo Wang", "Tianhao Wu", "Julien Barbaud", "Weiyu Kong", "Danyu Cui", "Han-Hsu Chen", "Xudong Yang", "Liyuan Han" ], "corpus_id": 201015754, "doc_id": "201015754", "n_citations": 167, "n_key_citations": 0, "score": 1, "title": "Stabilizing heterostructures of soft perovskite semiconductors", "venue": "Science", "year": 2019 }, { "abstract": "Epitaxial heterostructures based on oxide perovskites and III V, II VI and transition metal dichalcogenide semiconductors form the foundation of modern electronics and optoelectronics 1 7 Halide perovskites an emerging family of tunable semiconductors with desirable properties are attractive for applications such as solution processed solar cells, light emitting diodes, detectors and lasers 8 15 Their inherently soft crystal lattice allows greater tolerance to lattice mismatch, making them promising for heterostructure formation and semiconductor integration 16 17 Atomically sharp epitaxial interfaces are necessary to improve performance and for device miniaturization. However, epitaxial growth of atomically sharp heterostructures of halide perovskites has not yet been achieved, owing to their high intrinsic ion mobility, which leads to interdiffusion and large junction widths 18 21 and owing to their poor chemical stability, which leads to decomposition of prior layers during the fabrication of subsequent layers. Therefore, understanding the origins of this instability and identifying effective approaches to suppress ion diffusion are of great importance 22 26 Here we report an effective strategy to substantially inhibit in plane ion diffusion in two dimensional halide perovskites by incorporating rigid p conjugated organic ligands. We demonstrate highly stable and tunable lateral epitaxial heterostructures, multiheterostructures and superlattices. Near atomically sharp interfaces and epitaxial growth are revealed by low dose aberration corrected high resolution transmission electron microscopy. Molecular dynamics simulations confirm the reduced heterostructure disorder and larger vacancy formation energies of the two dimensional perovskites in the presence of conjugated ligands. These findings provide insights into the immobilization and stabilization of halide perovskite semiconductors and demonstrate a materials platform for complex and molecularly thin superlattices, devices and integrated circuits. An epitaxial growth strategy that improves the stability of two dimensional halide perovskites by inhibiting ion diffusion in their heterostructures using rigid p conjugated ligands is demonstrated, and shows near atomically sharp interfaces.", "author_names": [ "Enzheng Shi", "Biao Yuan", "Stephen B Shiring", "Yao Gao", "", "Yunfan Guo", "Cong Su", "Minliang Lai", "Peidong Yang", "Jing Kong", "Brett M Savoie", "Yi Yu", "Letian Dou" ], "corpus_id": 216649846, "doc_id": "216649846", "n_citations": 63, "n_key_citations": 0, "score": 0, "title": "Two dimensional halide perovskite lateral epitaxial heterostructures", "venue": "Nature", "year": 2020 }, { "abstract": "Formation of heterostructures is often inevitable in two dimensional (2D) halide perovskites and band alignment in 2D perovskite heterostructures is of central importance to their applications. However, controversies abound in literature on the band alignment of the 2D perovskite heterostructures. While external factors have been sought to reconcile the controversies, we show that the 2D perovskite heterostructures are in fact intrinsically prone to band \"misalignment\" driven by thermal fluctuations. Owing to the \"softness\" of inorganic layers in the perovskites, electron phonon coupling at room temperature could be strong enough to override band offsets at zero temperature, leading to oscillational band alignment between type I and type II at 300 K. We further demonstrate that by tuning the inorganic layers, one can increase the band offsets and stabilize the band alignment, paving the way for optoelectronic applications of the 2D perovskite heterostructures.", "author_names": [ "Linghai Zhang", "Xu Zhang", "Gang Lu" ], "corpus_id": 214694424, "doc_id": "214694424", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Band Alignment in Two Dimensional Halide Perovskite Heterostructures: Type I or Type II?", "venue": "The journal of physical chemistry letters", "year": 2020 }, { "abstract": "Significance Functional semiconductor heterojunctions are fundamental units for building up advanced optoelectronics and circuits. Halide perovskites, representing a new class of semiconductors with soft and reconfigurable ionic bonding, hold promise for a variety of applications because of their many unusual, tunable physical properties. This paper reports the formation of the current rectifying p n heterojunction in single crystalline CsSnI3 nanowires via localized phase transition between the n type yellow and p type black phases. We attribute the distinction of majority carrier types in these two phases to the different formation energies of the cation and anion vacancies. The present approach to heterojunction formation could inspire deeper understanding of phase transition dynamics and enable precise control over the design of functional heterostructures using halide perovskite building blocks. Semiconductor p n junctions are fundamental building blocks for modern optical and electronic devices. The p and n type regions are typically created by chemical doping process. Here we show that in the new class of halide perovskite semiconductors, the p n junctions can be readily induced through a localized thermal driven phase transition. We demonstrate this p n junction formation in a single crystalline halide perovskite CsSnI3 nanowire (NW) This material undergoes a phase transition from a double chain yellow (Y) phase to an orthorhombic black (B) phase. The formation energies of the cation and anion vacancies in these two phases are significantly different, which leads to n and p type electrical characteristics for Y and B phases, respectively. Interface formation between these two phases and directional interface propagation within a single NW are directly observed under cathodoluminescence (CL) microscopy. Current rectification is demonstrated for the p n junction formed with this localized thermal driven phase transition.", "author_names": [ "Qiao Kong", "Woochul Lee", "Minliang Lai", "Connor G Bischak", "Guoping Gao", "Andrew Barnabas Wong", "Teng Lei", "Yi Yu", "Lin-wang Wang", "Naomi S Ginsberg", "Peidong Yang" ], "corpus_id": 52054020, "doc_id": "52054020", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Phase transition induced p n junction in single halide perovskite nanowire", "venue": "Proceedings of the National Academy of Sciences", "year": 2018 }, { "abstract": "A simple method (which could be completed within 60 minutes at 298 K) was developed to transform layered organic inorganic metal halide perovskites into colloidal lyotropic liquid crystalline dispersions with microscopic structural orderliness as well as semiconducting properties and photoluminescence. Experimentally, hexagonal shaped mesogenic nanoplatelets of two dimensional lead iodide perovskites (R NH3)2PbI4 were synthesized by antisolvent induced rapid microcrystallization and stabilized by surfactants, and self assembled into discotic nematic phases with optical anisotropy and greenish blue fluorescence. Combining the stimuli responsive, light interactive, and reconfigurable ordered structures of liquid crystals with the adjustable semiconductivity of hybrid perovskites, these photoluminescent soft anisotropic materials may be used for polarized light emission or detection.", "author_names": [ "Pei-Xi Wang" ], "corpus_id": 233327412, "doc_id": "233327412", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Lyotropic liquid crystalline phases of anisotropic nanoparticles of organic inorganic metal halide perovskites: photoluminescence from self assembled ordered microstructures of semiconductors.", "venue": "Chemical communications", "year": 2021 }, { "abstract": "Halide perovskite (HP) semiconductors exhibit unique strong coupling between the electronic and structural dynamics. The high temperature cubic phase of HPs is known to be entropically stabilized, with imaginary frequencies in the calculated phonon dispersion relation. Similar calculations, based on the static average crystal structure, predict a stable tetragonal phase with no imaginary modes. This work shows that in contrast to standard theory predictions, the room temperature tetragonal phase of CH$_{3} $NH$_{3} $PbI$_{3} is strongly anharmonic. We use Raman polarization orientation (PO) measurements and \\textit{ab initio} molecular dynamics (AIMD) to investigate the origin and temperature evolution of the strong structural anharmonicity throughout the tetragonal phase. Raman PO measurements reveal a new spectral feature that resembles a soft mode. This mode shows an unusual continuous increase in damping with temperature which is indicative of an anharmonic potential surface. The analysis of AIMD trajectories identifies two major sources of anharmonicity: the orientational unlocking of the [CH$_{3} $NH$_{3} ions and large amplitude octahedral tilting that continuously increases with temperature. Our work suggests that the standard phonon picture cannot describe the structural dynamics of tetragonal CH$_{3} $NH$_{3} $PbI$_{3}", "author_names": [ "Rituraj Sharma", "Zhenbang Dai", "Lingyuan Gao", "Thomas M Brenner", "Lena Yadgarov", "Jiahao Zhang", "Yevgeny Rakita", "Roman Korobko", "Andrew M Rappe", "Omer Yaffe" ], "corpus_id": 218665233, "doc_id": "218665233", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "The tetragonal phase of CH$_{3}$NH$_{3}$PbI$_{3} is strongly anharmonic", "venue": "", "year": 2020 }, { "abstract": "The recent observation of superconductivity in Nd$_{0.8}$Sr$_{0.2}$NiO$_{2} calls for further investigation and optimization of the synthesis of this metastable infinite layer nickelate structure. Here, we present our current understanding of important aspects of the growth of the parent perovskite compound via pulsed laser deposition on SrTiO$_{3} (001) substrates, and the subsequent topotactic reduction. We find that to achieve single crystalline, single phase superconducting Nd$_{0.8}$Sr$_{0.2}$NiO$_{2} it is essential that the precursor perovskite Nd$_{0.8}$Sr$_{0.2}$NiO$_{3} thin film is stabilized with high crystallinity and no impurity phases; in particular, a Ruddlesden Popper type secondary phase is often observed. We have further investigated the evolution of the soft chemistry topotactic reduction conditions to realize full transformation to the infinite layer structure with no film decomposition or formation of other phases. We find that capping the nickelate film with a subsequent SrTiO$_{3} layer provides an epitaxial template to the top region of the nickelate film, much like the substrate. Thus, for currently optimized growth conditions, we can stabilize superconducting single phase Nd$_{0.8}$Sr$_{0.2}$NiO$_{2} (001) epitaxial thin films up to 10 nm.", "author_names": [ "Kyuho Lee", "Berit H Goodge", "Motoki Osada", "Lena F Kourkoutis" ], "corpus_id": 211146089, "doc_id": "211146089", "n_citations": 31, "n_key_citations": 1, "score": 0, "title": "Aspects of the synthesis of thin film superconducting infinite layer nickelates", "venue": "", "year": 2020 }, { "abstract": "First experimental observations of the ferromagnetic shielding effect in high Tc superconducting coated conductors were carried out. Experimental results were compared to simulations calling upon finite element calculations based on the H formulation of Maxwell equations to model superconducting strips with ferromagnetic shields. Samples of copper stabilized coated conductors were electroplated with nickel shields and afterwards characterized. Both externally applied oscillating transverse magnetic fields as well as transport currents were studied. Having observed promising gains with respect to the reduction of ac losses in both cases, we further investigated the potential of ferromagnetic shielding. The numerical model was able to reproduce and also predict experimental results very well and will serve as an indispensable tool to determine the potential of soft ferromagnetic materials to significantly reduce hysteretic losses.", "author_names": [ "Philip J Krueger", "Francesco Grilli", "Michal Vojenvciak", "Victor Manuel Rodriguez Zermeno", "Eduard Demencik", "Stefania Farinon Karlsruhe Institute of TechnologyGermany", "Istituto Nazionale di Fisica NucleareItaly" ], "corpus_id": 119221070, "doc_id": "119221070", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Superconductor/ferromagnet heterostructures exhibit potential for significant reduction of hysteretic losses", "venue": "", "year": 2013 }, { "abstract": "Abstract The effect of growth conditions on interfacial roughness in InAs/GaAs hetcrostructures prepared by molecular beam epitaxy has been investigated using synchrotron radiation. Measurement of grazing incidence X ray reflectivity (GIXR) and total electron yield (TEY) in the soft X ray wavelengths are used for nondestructive characterization of interfacial roughness in these semiconductor heterojunctions. Our results indicate that a smoothing process takes place during epitaxial growth, and that the measured interfacial roughness is lowest for In stabilized deposition on a GaAs substrate at 2deg off (100) and highest with As stabilized overgrowth on GaAs(100) The surface and interfacial roughness are practically independent of the layer thickness in the range investigated (70 600 A)", "author_names": [ "Andrzej Krol", "C J Sher", "D R Storch", "S C Woronick", "Y H Kao", "L L Chang", "Hiro Munekata" ], "corpus_id": 96164426, "doc_id": "96164426", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Soft x ray investigation of the effect of growth conditions on InAs/GaAs heterostructures", "venue": "", "year": 1990 }, { "abstract": "Hybrid perovskites have emerged over the past five years as absorber layers for novel high efficiency low cost solar cells combining the advantages of organic and inorganic semiconductors. Unfortunately, electrical transport in these materials is still poorly understood. Employing the linear response approach of density functional theory, we reveal strong anharmonic effects and a double well phonon instability at the center of the Brillouin zone for both cubic and orthorhombic phases of inorganic CsPbI3. Previously reported soft phonon modes are stabilized at the actual lower symmetry equilibrium structure, which occurs in a very flat energy landscape, highlighting the strong competition between the different phases of CsPbI3. Factoring these low energy phonons into electron phonon interactions and band gap calculations could help better understand the electrical transport properties in these materials. Furthermore, the perovskite oscillations through the corresponding energy barrier could explain the underlying ferroelectricity and the dynamical Rashba effect predicted in halide perovskites for photovoltaics.", "author_names": [ "Arthur Marronnier", "Heejae Lee", "Bernard Geffroy", "Jacky Even", "Yvan Bonnassieux", "Guido Roma" ], "corpus_id": 46803366, "doc_id": "46803366", "n_citations": 69, "n_key_citations": 1, "score": 0, "title": "Structural Instabilities Related to Highly Anharmonic Phonons in Halide Perovskites.", "venue": "The journal of physical chemistry letters", "year": 2017 } ]

[ { "abstract": "A single phase high efficiency near unity power factor (PF) half bridge boost converter circuit, which has been proposed earlier by other researchers, is presented with detailed analysis. This converter is capable of operating under variable PF. However, the focus of this paper is in achieving unity PF operation only. The efficiency of this circuit is high because there is only one series semiconductor on state voltage drop at any instant. The existence of an imbalance in the voltages of the two DC link capacitors, which was noted before, is confirmed here. The cause for the imbalance is analyzed using appropriate models, and a control method to eliminate it is discussed in detail. Analysis and design considerations for the power circuit using the fixed band hysteresis current control (HCC) technique are provided. The analytical results are verified through simulation using switched and averaged circuit models of the scheme and also through experimental work. At 90 V AC input and 300 W 300 V output, the experimental prototype demonstrates an efficiency of 96.23% and a PF of 0.998. This converter, with its relatively high DC output voltage, is well suited for the 110 V utility supply system. A circuit modification for universal input voltage range operation is also suggested.", "author_names": [ "R Srinivasan", "Ramesh Oruganti" ], "corpus_id": 110247773, "doc_id": "110247773", "n_citations": 178, "n_key_citations": 20, "score": 1, "title": "A unity power factor converter using half bridge boost topology", "venue": "", "year": 1998 }, { "abstract": "A single phase, high efficiency, and near unity power factor half bridge boost power converter circuit, which has been proposed earlier by other researchers, is presented with detailed analysis. Though this power converter is capable of operating under variable power factor, the focus of this paper is in achieving unity power factor operation only. The efficiency of this circuit is high because there is only one series semiconductor on state voltage drop at any instant. The existence of an imbalance in the voltages of the two DC link capacitors, which was noted before, is confirmed here. The cause of the imbalance is analysed using appropriate models, and a control method to eliminate it is discussed in detail. Analysis and design considerations for the power circuit using the fixed band hysteresis current control technique are provided. The analytical results are verified through simulation using switched and averaged circuit models of the scheme and also through experimental work. At 90 V AC input and 300 W, 300 V output, the experimental prototype demonstrates an efficiency of 96% and a power factor of 0.998. This power converter, with its relatively high DC output voltage, is well suited for 110 V utility supply system. A circuit modification for universal input voltage range operation is also suggested.", "author_names": [ "R Srinivasan", "Ramesh Oruganti" ], "corpus_id": 109840098, "doc_id": "109840098", "n_citations": 18, "n_key_citations": 1, "score": 0, "title": "Analysis and design of power factor correction using half bridge boost topology", "venue": "Proceedings of APEC 97 Applied Power Electronics Conference", "year": 1997 }, { "abstract": "In this paper, a single phase Power Factor Corrector (PFC) based on a two switch asymmetric half bridge Boost converter is analyzed. This topology improves the source current shaping by avoiding the control detuning phenomenon from which suffers the conventional single switch boost PFC, especially at very low input voltage. Pulse Width Modulated (PWM) multi loops control schemes are proposed and developed in order to ensure a unity power factor at the AC source side and a regulated voltage at the DC load side. The first one uses the simple and robust hysteretic based controller; the second one employs a conventional PI regulator, whereas the third one is based on the model nonlinearity compensation approach. The design of the last two control methods is based on the state space averaged model of the converter. The performance of the different control strategies is evaluated through simulations carried out on a numerical version of the converter. The implemented model of the converter is obtained by using the switching function technique. The control system is tested under both rated and disturbed operating conditions. The system performance is evaluated in terms of source current Total Harmonic Distortion (THD) input power factor and DC voltage regulation.", "author_names": [ "Hadi Youssef Kanaan", "Kamal Al-Haddad", "Maurice Fadel" ], "corpus_id": 20441096, "doc_id": "20441096", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Modeling and control of a two switch asymmetrical half bridge Boost Power Factor Corrector for single phase rectifiers", "venue": "2013 IEEE International Symposium on Industrial Electronics", "year": 2013 }, { "abstract": "Digital Simulation and implementation of a Power Factor Correction (PFC) half bridge converter based adjustable speed voltage controlled VSI fed PMBLDC motor is presented in this paper. A single phase AC DC converter topology based on the half bridge converter is employed for PFC which ensures near unity power factor over wide speed range. The proposed speed control scheme has the concept of DC link voltage control proportional to the desired speed of the PMBLDC motor. The PFC converter based PMBLDCM drive is designed, modeled and simulated using MATLABSimuLink environment. This drive ensures high accuracy and robust operation from near zero to high speed. Simulation and experimental results of these systems are presented and the performance measures are compared. The simulation and experimental results with bridgeless boost converter show that there is an improvement in power factor.", "author_names": [ "Chandrahasan Umayal", "B Janani", "S Rama Reddy" ], "corpus_id": 17216666, "doc_id": "17216666", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "DIGITAL IMPLEMENTATION OF PFC HALF BRIDGE CONVERTER FED PMBLDC MOTOR USING MICROCONTROLLER", "venue": "", "year": 2012 }, { "abstract": "A 3 phase PWM boost rectifier is described that uses DC link inductors and an asymmetrical half bridge to obtain a unity fundamental power factor supply current with a low total harmonic distortion. The paper describes how the rectifier circuit structure can be broken down to form a fundamental circuit topology that contains two mutually decoupled boost power converter circuits. These boost circuits contain two near triangular voltage sources, phase shifted from one another by 60/spl deg/ in the AC supply cycle, two DC link inductors and two semiconductor switches per circuit. The 3 phase bi directional switches used in the bridge have very low electrical stresses with a low switching frequency, zero voltage switching and a 0.2 p.u. current rating. Extensive analysis of the circuit switching states is presented and comparisons are made with 3 phase rectifiers using AC inductors. The operation of the rectifiers are illustrated with reference to simulation and experimental results.<ETX>", "author_names": [ "John C Salmon" ], "corpus_id": 109587609, "doc_id": "109587609", "n_citations": 37, "n_key_citations": 1, "score": 0, "title": "3 phase PWM boost rectifier circuit topologies using 2 level and 3 level asymmetrical half bridges", "venue": "Proceedings of 1995 IEEE Applied Power Electronics Conference and Exposition APEC'95", "year": 1995 }, { "abstract": "This study deals with the design, modelling and implementation of unity power factor (UPF) boundary conduction mode (BCM) based electronic ballast for a T8, 36 W fluorescent lamp. In low power applications, BCM based boost converter is widely used because of the low inductor value, however, because of zero crossover distortion, achieving a total harmonic distortion of <10% is difficult for universal AC mains. In proposed electronic ballast, UPF has been achieved at universal AC mains by using a boost power factor corrected converter operating in BCM with constant on time control. The achieved constant DC link voltage is converted into high frequency AC voltage using a quasi half bridge series resonant inverter to initiate the discharge and also to drive the fluorescent lamp with constant current. The modelling and simulation of the proposed topology have been performed using sim power system tool boxes in MATLAB Simulink environment. The switching losses have been reduced by achieving zero voltage switching at an operating switching frequency of 46 kHz. Different evaluated parameters have been found as per the international standard IEC61000 3 2 of class C regulations.", "author_names": [ "Ashish Shrivastava", "Bhim Singh" ], "corpus_id": 108986627, "doc_id": "108986627", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "Constant on time controlled zero voltage switching electronic ballast with power quality improvement", "venue": "", "year": 2015 }, { "abstract": "This paper proposes a dimmable light emitting diode (LED) driver featuring a high power factor and zero voltage switching on (ZVS) The circuit is obtained by integrating a boost converter and a dc dc converter with half bridge topology. The high power factor is achieved by operating the boost converter in discontinuous current mode (DCM) The LEDs are dimmed by the control scheme of asymmetrical pulse width modulation (ASPWM) The developed circuit eliminates the inherited dc offset current of the transformer in a conventional asymmetrical half bridge converter by introducing a balance capacitor. Both active switches can operate at ZVS by freewheeling the boost inductor current and the transformer magnetizing current to discharge the energy stored in their parasitic capacitance. The circuit operation is analyzed in detailed, and mathematical equations are derived. Finally, a 115 W prototype circuit for driving high brightness LEDs was built and tested. The experimental results verify the feasibility of the proposed LED driver with satisfactory performance. It can achieve a high power factor and ZVS operation.", "author_names": [ "Hung-Liang Cheng", "Yong-Nong Chang", "Lain-Chyr Hwang", "Hau-Chen Yen", "Shun-Yu Chan", "Wen-Fu Yang" ], "corpus_id": 218826713, "doc_id": "218826713", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A High Power Factor Dimmable LED Driver with Integrated Boost Converter and Half Bridge Topology Converter", "venue": "", "year": 2020 }, { "abstract": "LLC resonant converters are one of the best choices in AC DC converters. But, low power factor is a serious problem in AC DC LLC resonant converters. Adding a boost circuit in front of the converter improves the power factor albeit the increase in circuit complexity. To reduce the size and cost, both the boost and LLC stage can be controlled by the same switches. However, these single stage topologies are less efficient in regulating DC bus capacitor voltage pertaining to transients in the line voltage and load conditions. The paper proposes a new single stage topology for AC DC LLC resonant converters. The circuit consists of three level half bridge flying capacitor topology. Discontinuous conduction mode ensures inherent unity power factor operation. Switching frequency control and PWM duty ratio control are used to regulate the output voltage and bus capacitor voltages of the converter respectively. This dual control scheme makes the converter DC bus voltage nearly constant over a wide range of load and line voltage variations. Furthermore, the three level topology guarantees reduced switching stress and losses. The operation of the topology has been validated using MATLAB simulation.", "author_names": [ "Antony K Peter", "Jaison Mathew" ], "corpus_id": 148574103, "doc_id": "148574103", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Three Level Half Bridge Flying Capacitor Topology for Single Stage AC DC LLC Resonant Converter", "venue": "2018 IEEE International Conference on Power Electronics, Drives and Energy Systems (PEDES)", "year": 2018 }, { "abstract": "This paper presents a power factor corrected (PFC) boost converter based half bridge LLC resonant converter (LLC) for electric vehicle battery charging application. The proposed converter utilizes a boost converter as a front end converter operating in continuous inductor conduction mode (CICM) to achieve unity power factor at AC mains, and LLC to facilitate the EV battery charging. The boost converter is operated in pulse width modulation (PWM) at fixed frequency, whereas LLC converter uses pulse frequency modulation (PFM) technique to maintain power delivered to the battery. A 2kW rating prototype of the proposed converter is designed and implemented using TMS320F28035 microcontroller. The performance of proposed converter is presented under various load and line conditions", "author_names": [ "Rahul Pandey", "Bhim Singh" ], "corpus_id": 148573478, "doc_id": "148573478", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A Power Factor Corrected Electric Vehicle Battery Charger Using Boost Converter", "venue": "2018 8th IEEE India International Conference on Power Electronics (IICPE)", "year": 2018 }, { "abstract": "Photovoltaic (PV) inverters form the backbone of PV generation. This paper proposes an all film capacitor, transformerless single phase inverter for PV application. The topology is a combination of a front end boost stage, a half bridge (HB) inverter stage, and a buck boost power decoupling stage. The grid ripple power is decoupled by a large swing of the HB capacitors along with a limited ripple on the dc link, thus reducing the capacitance requirement and converter volume. Being an HB derived inverter, the high frequency common mode leakage current through the PV parasitic capacitance is mitigated. Furthermore, the dc link average is optimally controlled to ensure a higher efficiency over wide operating load and power factor range. To validate its operation, a Silicon Carbide based 1 kVA laboratory prototype is built and closed loop experimental results are provided at 100/75 kHz switching frequency over wide operating conditions.", "author_names": [ "Jinia Roy", "Yinglai Xia", "Raja Ayyanar" ], "corpus_id": 116607197, "doc_id": "116607197", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Half Bridge Voltage Swing Inverter With Active Power Decoupling for Single Phase PV Systems Supporting Wide Power Factor Range", "venue": "IEEE Transactions on Power Electronics", "year": 2019 } ]

[ { "abstract": "The most common approaches to generating power from sunlight are either photovoltaic, in which sunlight directly excites electron hole pairs in a semiconductor, or solar thermal, in which sunlight drives a mechanical heat engine. Photovoltaic power generation is intermittent and typically only exploits a portion of the solar spectrum efficiently, whereas the intrinsic irreversibilities of small heat engines make the solar thermal approach best suited for utility scale power plants. There is, therefore, an increasing need for hybrid technologies for solar power generation. By converting sunlight into thermal emission tuned to energies directly above the photovoltaic bandgap using a hot absorber emitter, solar thermophotovoltaics promise to leverage the benefits of both approaches: high efficiency, by harnessing the entire solar spectrum; scalability and compactness, because of their solid state nature; and dispatchablility, owing to the ability to store energy using thermal or chemical means. However, efficient collection of sunlight in the absorber and spectral control in the emitter are particularly challenging at high operating temperatures. This drawback has limited previous experimental demonstrations of this approach to conversion efficiencies around or below 1% (refs 9, 10, 11) Here, we report on a full solar thermophotovoltaic device, which, thanks to the nanophotonic properties of the absorber emitter surface, reaches experimental efficiencies of 3.2% The device integrates a multiwalled carbon nanotube absorber and a one dimensional Si/SiO2 photonic crystal emitter on the same substrate, with the absorber emitter areas optimized to tune the energy balance of the device. Our device is planar and compact and could become a viable option for high performance solar thermophotovoltaic energy conversion.", "author_names": [ "Andrej Lenert", "David M Bierman", "Youngsuk Nam", "Walker R Chan", "Ivan Celanovic", "Marin Soljacic", "Evelyn N Wang" ], "corpus_id": 18478048, "doc_id": "18478048", "n_citations": 538, "n_key_citations": 9, "score": 1, "title": "A nanophotonic solar thermophotovoltaic device.", "venue": "Nature nanotechnology", "year": 2014 }, { "abstract": "Eq. 1 in this Letter (and also, Eq. 1.133 in ref 2) represents the temperature required for the maximum of Planck's distribution expressed in units of wavelength to match the bandgap energy. However, the energy at which the maximum occurs depends on whether we consider energy flux per unit frequency range or per unit wavelength range3,4. A more appropriate approximation matches the maximum of Planck's distribution expressed in units of frequency or energy to the bandgap energy, the scaling factor in this case is 4114 K/eV.", "author_names": [ "Andrej Lenert", "David M Bierman", "Youngsuk Nam", "Walker R Chan", "Ivan Celanovic", "Marin Soljacic", "Evelyn N Wang" ], "corpus_id": 33663871, "doc_id": "33663871", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Addendum: A nanophotonic solar thermophotovoltaic device.", "venue": "Nature nanotechnology", "year": 2015 }, { "abstract": "", "author_names": [ "Andrej Lenert", "David M Bierman", "Youngsuk Nam", "Walker R Chan", "Ivan Celanovic", "Marin Soljacic", "Evelyn N Wang" ], "corpus_id": 125254579, "doc_id": "125254579", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Erratum: A nanophotonic solar thermophotovoltaic device (Nature Nanotechnology (2014) 9 (126 130)", "venue": "", "year": 2015 }, { "abstract": "Solar thermal energy conversion can harness the entire solar spectrum and theoretically achieve very high efficiencies while interfacing with thermal storage or back up systems for dispatchable power generation. Nanostructured materials allow us to tune the spectral properties and heat transfer behavior to enable such systems. However, under high temperature conditions, thermal management, system optimization and minimization of parasitic losses are necessary to achieve competitive solar power generation. This thesis seeks to achieve spectral control and thermal management through manipulation of nanostructured materials. First, this thesis presents the design and development of a nanophotonic solar thermophotovoltaic (STPV) that harnesses the full spectrum of the sun, in a solid state and scalable way. Through device optimization and control over spectral properties at high temperatures 1300 K) a device that is 3 times more efficient than previous STPVs is demonstrated. To achieve this result, a framework was developed to identify which parts of the spectrum are critical and to guide the design of nanostructured absorbers and emitters for STPVs. The work elucidated the relative importance of spectral properties depending on the operating regime and device geometry. Carbon nanotubes and a silicon/silicon dioxide photonic crystal were used to target critical properties in the high solar concentration regime; and two dimensional metallic photonic crystals were used to target critical properties in the low solar concentration regime. A versatile 5 experimental platform was developed to interchangeably test different STPV components without sacrificing experimental control. In addition to demonstrating significant improvements in STPV efficiency, an experimental procedure to quantify the energy conversion and loss mechanisms helped improve and validate STPV models. Using these validated models, this thesis presents a scaled up device that can achieve 20% efficiencies in the near term. With potential integration of thermal based storage, such a technology can supply power efficiently and on demand, which will have significant implications for adoption of STPVs. Second, the thesis shifts focus away from solid state systems to thermal fluid systems. A new figure of merit was proposed to capture the thermal storage, heat transfer and pumping power requirements for a heat transfer fluid is a solar thermal system. Existing and emerging fluids were evaluated based on the new metric as well as practical issues. Finally, sub micron phase change material (PCM) suspensions are investigated for simultaneous enhancement of local heat transfer and thermal storage capacity in solar thermal systems. A physical model was developed to explain the local heat transfer characteristics of a flowing PCM suspension undergoing melting. A mechanism for enhancement of heat transfer through.control over the distribution of PCM particles inside a channel was discovered and explained. Together, this thesis makes significant contributions towards improving our understanding of the role and the effective use of nanostructured materials in solar thermal systems. Thesis Committee Chair: Professor Evelyn N. Wang, Department of Mechanical Engineering, MIT Thesis Committee Members: Professor Gang Chen, Department of Mechanical Engineering, MIT Professor Carl V. Thompson, Department of Material Science and Engineering, MIT", "author_names": [ "Andrej Lenert" ], "corpus_id": 137291766, "doc_id": "137291766", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Tuning energy transport in solar thermal systems using nanostructured materials", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "Youngsuk Nam", "Andrej Lenert", "David M Bierman", "Evelyn N Wang" ], "corpus_id": 112296944, "doc_id": "112296944", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solar Thermophotovoltaic Devices with Nanophotonic Absorbers and Emitters", "venue": "", "year": 2014 }, { "abstract": "The overall efficiency of solar thermophotovoltaic (STPV) systems, which can theoretically reach 85.4% is function of a large number of parameters, such as concentration factor, device geometry, cell bandgap, absorber and cell temperatures, In actual STPV devices, the cell temperature depends on the chosen configuration and on the characteristics of the cooling system, i.e. temperature and heat transfer coefficient. This article presents an original optimization that takes into account the thermal equilibrium of the PV cell. Simulations demonstrate the impact of the thermal boundary conditions on the optimum set of parameters for STPV power generation. These results highlight the importance of considering the thermal behavior in the global optimization of experimental STPV devices.", "author_names": [ "Olivier Dupre", "Rodolphe Vaillon", "Martin A Green" ], "corpus_id": 47572642, "doc_id": "47572642", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optimization of solar thermophotovoltaic systems including the thermal balance", "venue": "2017 IEEE 44th Photovoltaic Specialist Conference (PVSC)", "year": 2017 }, { "abstract": "The overall efficiency of solar thermophotovoltaic (STPV) systems, which can theoretically reach 85.4% is function of a large number of parameters, such as concentration factor, device geometry, cell bandgap, absorber and cell temperatures, In actual STPV devices, the cell temperature depends on the chosen configuration and on the characteristics of the cooling system, i.e. temperature and heat transfer coefficient. This article presents an original optimization that takes into account the thermal equilibrium of the PV cell. Simulations demonstrate the impact of the thermal boundary conditions on the optimum set of parameters for STPV power generation. These results highlight the importance of considering the thermal behavior in the global optimization of experimental STPV devices.", "author_names": [ "Olivier Dupre", "Rodolphe Vaillon", "Martin A Green" ], "corpus_id": 33772681, "doc_id": "33772681", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Optimization of solar thermophotovoltaic systems including the thermal balance", "venue": "2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)", "year": 2016 }, { "abstract": "Summary Recent trends in photovoltaics demand ever thin solar cells to allow deployment in consumer oriented products requiring low cost and mechanically flexible devices. For this, nanophotonic elements in the wave optics regime are highly promising, as they capture and trap light in the cells' absorber, enabling its thickness reduction while improving its efficiency. Here, novel wavelength sized photonic structures were computationally optimized toward maximum broadband light absorption. Thin film silicon cells were the test bed to determine the best performing parameters and study their optical effects. Pronounced photocurrent enhancements, up to 37% 27% and 48% respectively, in ultra thin (100 and 300 nm thick) amorphous, and thin (1.5 mm) crystalline silicon cells are demonstrated with honeycomb arrays of semi spheroidal dome or void like elements patterned on the cells' front. Also importantly, key advantages in the electrical performance are anticipated, since the photonic nano/micro nanostructures do not increase the cell roughness, therefore not contributing to recombination, which is a crucial drawback in state of the art light trapping approaches.", "author_names": [ "Manuel J Mendes", "Sirazul Haque", "Olalla Sanchez-Sobrado", "Andreia Araujo", "Hugo Aguas", "Elvira Fortunato", "Rodrigo Martins" ], "corpus_id": 52280818, "doc_id": "52280818", "n_citations": 23, "n_key_citations": 2, "score": 0, "title": "Optimal Enhanced Solar Cell Ultra thinning with Broadband Nanophotonic Light Capture", "venue": "iScience", "year": 2018 }, { "abstract": "We have demonstrated world record thermophotovoltaic (TPV) conversion efficiency in two materials systems operating at two different thermal emitter temperatures. A GaAs based PV device under a 2330 degC thermal emitter produced an efficiency of (31 2) and an In0.53Ga0.47As based PV device under a 1300 degC thermal emitter produced an efficiency of (30 2) The electrical output power densities of the cells were 2.45 W/cm2 and 0.658 W/cm2, respectively. Critical to these high efficiencies were the cells' high reflectance of photon energies below the absorber band gap. Unlike solar PV, for which sub band gap (SBG) light is lost, a TPV cell can reflect SBG light back to the thermal emitter where it can be recycled. The demonstrations were made on a custom built measurement platform in which a 100 cm2 graphite thermal emitter was heated under vacuum. The TPV efficiencies were evaluated by comparing the measured electrical output power of the cell with the total power absorbed by the cell. The measured TPV efficiencies as a function of thermal emitter temperature were corroborated by our full system modeling. As far as the authors are aware, these are the highest TPV conversion efficiencies ever measured, and device improvements should yield 40% efficiency in the near future.", "author_names": [ "Tarun C Narayan", "Leah Y Kuritzky", "Dustin P Nizamian", "Benjamin Anders Johnson", "Eric J Tervo", "Alexandra R Young", "Cecilia Luciano", "Madhan K Arulanandam", "Brendan M Kayes", "Emmett E Perl", "Moritz Limpinsel", "Parthiban Santhanam", "Jonathan Slack", "Waldo J Olavarria", "Jeffrey J Carapella", "Michelle S Young", "Cheng-Lun Wu", "Zhengshan J Yu", "Zachary C Holman", "Richard R King", "Myles A Steiner", "David M Bierman", "Andrew J Ponec", "Justin A Briggs" ], "corpus_id": 230995125, "doc_id": "230995125", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "World record demonstration of 30% thermophotovoltaic conversion efficiency", "venue": "2020 47th IEEE Photovoltaic Specialists Conference (PVSC)", "year": 2020 }, { "abstract": "We demonstrate an inverted metamorphic multijunction (IMM) photovoltaic cell comprising lattice mismatched 1.2 eV AlGaInAs and 1.0 eV GaInAs junctions optimized for high temperature thermophotovoltaic (TPV) applications. This device differs from traditional IMM solar cells because the mismatched junctions are grown at a single lattice constant. This architecture enables removal of the compositionally graded buffer that otherwise filters light from the junctions below and absorbs sub bandgap light via free carrier absorption. Sub bandgap absorption dramatically reduces the efficiency of TPV systems using high reflectivity cells to enable band edge spectrum filtering. Three components required development to enable this device: (1) a lattice mismatched 1.2 eV AlGaInAs junction, (2) a metamorphic contact layer grown after the graded buffer, and (3) a transparent tunnel junction that sits in front of the 1.0 eV GaInAs junction. Growth conditions that minimize oxygen defect incorporation maximize AlGaInAs cell quality, enabling a 0.41 V bandgap open circuit voltage offset at 22 mA/cm2 under AM1.5D. A mismatched GaInAs:Se layer is developed as a low resistance contact. Lastly, we develop a GaAsSb:C/GaInP:Se tunnel junction suitable for high power densities with more transparency than the GaAsSb:C/GaInAs:Se structure used in past IMM cells. We characterize the tandem device under a high intensity spectrum that approximates the emission from a 2150 degC blackbody radiator and deduce a projected ideal TPV efficiency of 39.9% at ~30% of the blackbody irradiance and 36% ideal TPV efficiency under the full 118 W/cm2 irradiance. Improvements to the back surface reflectivity and series resistance are expected to increase the ideal TPV efficiency well above 40%", "author_names": [ "Kevin L Schulte", "Ryan M France", "Daniel J Friedman", "Alina LaPotin", "Asegun Henry", "Myles A Steiner" ], "corpus_id": 225123267, "doc_id": "225123267", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Inverted metamorphic AlGaInAs/GaInAs tandem thermophotovoltaic cell designed for thermal energy grid storage application", "venue": "", "year": 2020 } ]

[ { "abstract": "Polymeric graphitic carbon nitride (for simplicity, g C3N4) is a layered material similar to graphene, being composed of only C, N, and some impurity H. Contrary to graphenes, g C3N4 is a medium band gap semiconductor and an effective photocatalyst for a broad variety of reactions, and it possesses a high thermal and chemical stability In this Perspective, we describe the polycondensation of this structure, how to modify band positions and band gap by doping and copolymerization, and how to texture the organic solid to make it an effective photocatalyst. We then describe the photochemical splitting of water and some mild and selective photooxidation reactions catalyzed by g C3N4.", "author_names": [ "Xinchen Wang", "Siegfried Blechert", "Markus Antonietti" ], "corpus_id": 97372397, "doc_id": "97372397", "n_citations": 1065, "n_key_citations": 7, "score": 1, "title": "Polymeric Graphitic Carbon Nitride for Heterogeneous Photocatalysis", "venue": "", "year": 2012 }, { "abstract": "Polymeric graphitic carbon nitride (g C3N4) and various carbon materials have experienced a renaissance as viable alternates in photocatalysis due to their captivating metal free features, favorable photoelectric properties, and economic adaptabilities. Although numerous efforts have focused on the integration of both materials with optimized photocatalytic performance in recent years, the direct parameters for this emerging enhancement are not fully summarized yet. Fully understanding the synergistic effects between g C3N4 and carbon materials on photocatalytic action is vital to further development of metal free semiconductors in future studies. Here, recent advances of carbon/g C3N4 hybrids on various photocatalytic applications are reviewed. The dominant governing factors by inducing carbon into g C3N4 photocatalysts with involving photocatalytic mechanism are highlighted. Five typical carbon induced enhancement effects are mainly discussed here, i.e. local electric modification, band structure tailoring, multiple charge carrier activation, chemical group functionalization, and abundant surface modified engineering. Photocatalytic performance of carbon induced g C3N4 photocatalysts for addressing directly both the renewable energy storage and environmental remediation is also summarized. Finally, perspectives and ongoing challenges encountered in the development of metal free carbon induced g C3N4 photocatalysts are presented.", "author_names": [ "Lei Cheng", "Huaiwu Zhang", "Xiaoning Li", "Jiajie Fan", "Quanjun Xiang" ], "corpus_id": 227955706, "doc_id": "227955706", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Carbon Graphitic Carbon Nitride Hybrids for Heterogeneous Photocatalysis.", "venue": "Small", "year": 2020 }, { "abstract": "Abstract Water bodies throughout the world are severely affected by the discharge of industrial effluents contaminated with xenobiotic and recalcitrant substances. Due to the low biodegradability of these compounds, conventional treatments have proven to be insufficient for their removal. Although heterogeneous photocatalysis poses an alternative for the treatment of these substances, the overall solar activity of conventional photocatalysts (such as TiO2) is very limited because of their wide bandgap. Thus, new photocatalysts such as graphitic carbon nitride (g C3N4) which exhibits catalytic activity using longer wavelengths, are receiving increasing attention. In this work, g C3N4 irradiated with a high energy electron beam was investigated for the degradation of Direct Blue 1 azo dye. g C3N4 was synthesized by pyrolysis of urea and irradiated at doses between 2.2 and 25.0 kGy for different times. The irradiated material was characterized by X ray diffraction (XRD) electron spin resonance (ESR) Fourier transform infrared spectroscopy (FTIR) UV Vis spectroscopy and transmission electron microscopy (TEM) together with BET surface area measurements. The results showed that the irradiation of the catalyst improved its dye adsorption ability, and 5 kGy was found to be the optimum irradiation dose, increasing the maximum dye adsorption capacity of irradiated g C3N4 to 73.76 mg/g. No significant differences in the pseudo first order kinetic model constants of the photocatalytic degradation of the dye were observed as a result of the irradiation treatment, perhaps due to the blocking of the active sites of the catalyst after the adsorption step, but a 1.4 times higher activity was attained for the irradiated sample upon H2O2 addition. The presence of H2O2 promoted the photocatalytic degradation process, reaching 99% dye removal in 40 min, and improved the reusability of the catalyst. The proposed modification of g C3N4 holds promise to enhance its activity.", "author_names": [ "Grace Picho-Chillan", "Roberto C Dante", "Florinella Munoz-Bisesti", "Pablo Martin-Ramos", "Pedro Chamorro-Posada", "Paul Vargas-Jentzsch", "Francisco Manuel Sanchez-Arevalo", "Christian Sandoval-Pauker", "Dario Rutto" ], "corpus_id": 199079064, "doc_id": "199079064", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Photodegradation of Direct Blue 1 azo dye by polymeric carbon nitride irradiated with accelerated electrons", "venue": "Materials Chemistry and Physics", "year": 2019 }, { "abstract": "The creation and development of efficient solar energy conversion systems for artificial photosynthesis is one of the challenges of modern chemistry and materials. Currently, the search for sustainable and stable photocatalytic systems for CO2 reduction by visible light is being actively pursued. Many useful and energy rich chemicals (e.g. CH3OH and HCOOH) can be obtained by photocatalytic CO2 reduction, which can reduce the emissions of greenhouse gases. Recently, significant improvements have been achieved in the area of CO2 reduction by using a heterogeneous photocatalyst under visible light irradiation. However, most of the catalysts screened did not exceed the state of the art system with turnover numbers (TONs) of approximately 200 and apparent quantum yields (AQYs) of approximately 2 The introduction of melon based graphitic carbon nitride (gC3N4) polymers as solar energy transducers has significantly extended the scope of conventional inorganic photocatalysts to polymeric photocatalysts. The latter is even more promising than the conventional photocatalysts because it is metal free, sustainable, and has demonstrated the ability to induce water splitting, CO2 reduction, and selective organic synthesis by means of visible light. The use of g C3N4 for CO2 reduction is an emerging research topic that couples organic basic functionality to photocatalytic functionality and allows for activation/adsorption and reduction of CO2. In the previous system for CO2 to CO photocatalytic conversion the quantum yield is less than 1. Recently, Maeda and co workers have developed a promising heterogeneous system for the reduction of CO2 into formic acid under visible light irradiation by merging organometallic chemistry with polymer photocatalysis by using g C3N4 and a ruthenium complex as light harvesting units and catalytic active sites, respectively. By carefully optimizing the heterogeneous catalyst and the reaction conditions the AQY was remarkably enhanced to 5.7 with a high TON of >1000, which are the highest values for g C3N4 and are better than other heterogeneous photocatalysts working with visible light. The authors promote surface kinetics for both the reduction reaction and charge transfer by chemically modifying g C3N4 with a Ru complex by means of a surface chemistry strategy. The surface Ru complex catalysis is demonstrated to change reaction pathway to produce the more valuable product, formic acid, rather than carbon monoxide. Four different Ru based complexes (Scheme 1) trans (Cl)[Ru(bpyX2)(CO)2Cl2] (bpyX2 2,2' bipyridine with substituent X in the 4 position, X H, CH3, PO3H2, or CH2PO3H2) were used as kinetic promoters for CO2 reduction, along with a suitable reaction environment to increase the efficiency of the overall process. Mesoporous graphitic carbon nitride (mpg C3N4) with a specific surface area of 180 m gC/1 and pore volume of 0.7 cm gC/1 was selected as a light harvesting semiconductor. The surface of the porous organic photocatalyst is covered with amino groups, which can be easily functionalized by surface organic chemistry. This feature is unique and is not available for traditional inorganic photocatalysts. Results indicated that RuP and RuCP could adsorb on the surface of mpg C3N4 owing to the intense interaction between acid and base functional groups on the two units. However, no adsorption was found to occur for RuH and RuMe, which do not have an anchoring group. The rich amino groups on the surface of the gScheme 1. Photocatalytic CO2 reduction by Ru complex anchored g C3N4 photocatalysts. C.B. Conduction band, V.B. Valance band, D electron donor. Reprinted with permission from Ref. [1]", "author_names": [ "Guigang Zhang", "Zhi-An Lan", "Xinchen Wang" ], "corpus_id": 95996178, "doc_id": "95996178", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Merging Surface Organometallic Chemistry with Graphitic Carbon Nitride Photocatalysis for CO2 Photofixation", "venue": "", "year": 2015 }, { "abstract": "Photoredox catalysis comprising homogeneous transition metal based systems, organic dyes, and semiconductors, has become a universal tool to catalyze a wide variety of chemical reactions with high selectivity and under mild conditions using visible light irradiation. This Minireview summarizes recent progress in photoredox catalysis mediated by heterogeneous carbon nitride materials such as mesoporous graphitic carbon nitride (mpg CN) polymeric carbon nitride, and potassium poly(heptazine imides) (K PHI) Because of the high thermal, chemical, and photostability of these materials, as well as favorable conduction and valence band positions, carbon nitrides expand the reaction range of photocatalysis to many novel reactions, such as photocatalytic activation of elemental sulfur to furnish a convenient chemical route to organosulfur compounds.", "author_names": [ "Aleksandr Savateev", "Indrajit Ghosh", "Burkhard Konig", "Markus Antonietti" ], "corpus_id": 51890058, "doc_id": "51890058", "n_citations": 158, "n_key_citations": 0, "score": 0, "title": "Photoredox Catalytic Organic Transformations using Heterogeneous Carbon Nitrides.", "venue": "Angewandte Chemie", "year": 2018 }, { "abstract": "The future development of chemistry entails environmentally friendly and energy sustainable alternatives for organic transformations. Visible light photocatalysis can address these challenges, as reflected by recent intensive scientific endeavours to this end. This review covers state of the art accomplishments in visible light induced selective organic transformations by heterogeneous photocatalysis. The discussion comprises three sections based on the photocatalyst type: metal oxides such as TiO2, Nb2O5 and ZnO; plasmonic photocatalysts like nanostructured Au, Ag or Cu supported on metal oxides; and polymeric graphitic carbon nitride. Finally, recent strides in bridging the gap between photocatalysis and other areas of catalysis will be highlighted with the aim of overcoming the existing limitations of photocatalysis by developing more creative synthetic methodologies.", "author_names": [ "Xianjun Lang", "Xiaodong Chen", "Jincai Zhao" ], "corpus_id": 21473718, "doc_id": "21473718", "n_citations": 872, "n_key_citations": 2, "score": 0, "title": "Heterogeneous visible light photocatalysis for selective organic transformations.", "venue": "Chemical Society reviews", "year": 2014 }, { "abstract": "Abstract Developing bioinspired artificial Z scheme heterojunction photocatalysts with exceedingly well performance of visible light harnessing along with optimum band edge potentials is a robustly prominent avenue to combat the environmental and energy crisis. The current scenario in fixation of water shortages all over the world is utilisation of green and economical processes to maintain sustainability. In this regard, hybridizing fascinating metal free polymeric conjugated graphitic carbon nitride (g C3N4) with other components to tailor an effectual visibly driven photocatalyst has triggered a superfluity in the field of photocatalysis. Considering the great adherence and eloquent progress in exploitation of g C3N4 goaded Z scheme nanohybrids, we herein present an all inclusive and updated study about photocatalytic wastewater treatment including pollutant degradation and bacterial inactivation. An in depth overview comprising traditional photocatalysis along with Z scheme photocatalytic systems have been exploited and discussed with respect to their facile synthesis techniques and application in environmental restoration. With revamp strategies, g C3N4 based Z scheme photocatalytic systems provide broad range visible light absorption and efficient space separation of photo generated charge carriers, resulting in efficacious photoactivity. The mechanistic insights inferring photocarriers migration and separation along with the generation of reactive radical species involved in the photodegradation process has also been highlighted and discussed. Finally, an all embracing conclusive remark is presented regarding present studies and future perspectives for the development of g C3N4 goaded Z scheme photocatalysis.", "author_names": [ "Abhinandan Kumar", "Pankaj Raizada", "Pardeep Singh", "Reena V Saini", "Adesh K Saini", "Ahmad Hosseini-Bandegharaei" ], "corpus_id": 209730826, "doc_id": "209730826", "n_citations": 121, "n_key_citations": 0, "score": 0, "title": "Perspective and status of polymeric graphitic carbon nitride based Z scheme photocatalytic systems for sustainable photocatalytic water purification", "venue": "", "year": 2020 }, { "abstract": "Advanced oxidation processes (AOPs) have attracted much interest in the field of water treatment owing to their high removal efficiency for refractory organic contaminants. Graphitic carbon nitride (g C3N4) based catalysts with high performance and cost effectiveness are promising heterogeneous catalysts for AOPs. Most research on g C3N4 based catalysts focuses on photocatalytic oxidation, but increasingly researchers are paying attention to the application of g C3N4 based catalysts in other AOPs beyond photocatalysis. This review aims to concisely highlight recent state of the art progress of g C3N4 based catalysts in AOPs beyond photocatalysis. Emphasis is made on the application of g C3N4 based catalysts in three classical AOPs including Fenton based processes, catalytic ozonation and persulfates activation. The catalytic performance and involved mechanism of g C3N4 based catalysts in these AOPs are discussed in detail. Meanwhile, the effect of water chemistry including pH, water temperature, natural organic matter, inorganic anions and dissolved oxygen on the catalytic performance of g C3N4 based catalysts are summarized. Moreover, the reusability, stability and toxicity of g C3N4 based catalysts in water treatment are also mentioned. Lastly, perspectives on the major challenges and opportunities of g C3N4 based catalysts in these AOPs are proposed for better developments in the future research.", "author_names": [ "Chengyun Zhou", "Guangming Zeng", "Xiaopei Li" ], "corpus_id": 220796114, "doc_id": "220796114", "n_citations": 78, "n_key_citations": 0, "score": 0, "title": "Recent advances in application of graphitic carbon nitride based catalysts for degrading organic contaminants in water through advanced oxidation processes beyond photocatalysis: A critical review.", "venue": "Water research", "year": 2020 }, { "abstract": "Abstract Characteristics of polymeric and electronic structure of graphitic carbon nitride (g C3N4) responsible for the photocatalytic activity were analyzed with oxidation reaction of nitrogen monoxide (NO) and various kinds of spectroscopies. The photocatalytic activity per surface area was increased with increasing the preparation temperature up to 520 degC, and was decreased above 520 degC while the visible light absorbance and the relative surface area was increased with the preparation temperature up to 650 degC. Laser desorption/ionization mass spectrometry (LDI MS) showed that the content of cyano group connected with tri s triazine unit in g C3N4 increases with increasing the preparation temperature and that g C3N4 with higher activity per surface area contained smaller amount of cyano group. Additionally, the degree of polymerization and the planarity of carbon nitride layer possibly contributed for formation of mid gap levels that increases the number of unpaired electron. The formation of the mid gap level was not effective for the photocatalytic activity, but rather deactivated g C3N4.", "author_names": [ "Taizo Sano", "Hiroaki Sato", "Tomoko Hori", "Tsutomu Hirakawa", "Yoshiyuki Teramoto", "Kazuhide Koike" ], "corpus_id": 195554865, "doc_id": "195554865", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Effects of polymeric and electronic structure of graphitic carbon nitride (g C3N4) on oxidative photocatalysis", "venue": "Molecular Catalysis", "year": 2019 }, { "abstract": "In recent years, various facile and low cost methods have been developed for the synthesis of advanced nanostructured photocatalytic materials. These catalysts are required to mitigate the energy crisis, environmental deterioration, including water and air pollution. Among the various semiconductors explored, recently novel classes of polymeric graphitic carbon nitride (g C3N4) based heterogeneous photocatalysts have established much greater importance because of their unique physiochemical properties, large surface area, low price, and long service life, ease of synthesis, product scalability, controllable band gap properties, low toxicity, and high photocatalytic activity. The present comprehensive review focuses on recent achievements in a number of facile chemical synthesis methods for semiconducting polymeric carbon nitrides and their heterogeneous nanohybrids with various dopants, nanostructured metals, metal oxides, and nanocarbons, as well as the parameters influencing their physiochemical properties and photocatalytic efficiency, which are discussed with reference to various catalytic applications such as air (NOx) purification, wastewater treatment, hydrogen generation, CO2 reduction, and chemical transformation. The mechanisms for the superior photocatalytic activity of polymeric g C3N4 based heterogeneous photocatalysts are also discussed. Finally, the challenges, prospects, and future directions for photocatalytic polymeric g C3N4 based semiconducting materials are described.", "author_names": [ "Kakarla Raghava Reddy", "Ch Venkata Reddy", "Mallikarjuna N Nadagouda", "Nagaraj P Shetti", "Shim Jaesool", "Tejraj M Aminabhavi" ], "corpus_id": 73463414, "doc_id": "73463414", "n_citations": 184, "n_key_citations": 0, "score": 0, "title": "Polymeric graphitic carbon nitride (g C3N4) based semiconducting nanostructured materials: Synthesis methods, properties and photocatalytic applications.", "venue": "Journal of environmental management", "year": 2019 } ]

[ { "abstract": "The urgent need for clean and renewable energy drives the exploration of effective strategies to produce hydrogen. Semiconductor based photocatalytic hydrogen production technology is one of the ideal processes for direct solar energy conversion and storage that has been widely studied. The development of highly efficient photocatalysts is essential for the cost effective and large scale production of hydrogen. CdS based semiconductor photocatalysts have attracted significant attention due to their unique advantages, including strong visible light absorption capacity, suitable band edge levels and excellent electronic charge transfer. However, unlike TiO2 with good photostability, the intrinsic drawback of photocorrosion of CdS based semiconductors significantly challenges their durable application in photocatalysis. This review focuses on recent advances in material design and strategies for improving the anti photocorrosion of CdS based photocatalysts for applications in photocatalytic overall water splitting to produce hydrogen. Moreover, brief prospective development and challenges in the synthesis of anti corrosion CdS based photocatalysts are also presented.", "author_names": [ "Xiaofeng Ning", "Gongxuan Lu" ], "corpus_id": 209894784, "doc_id": "209894784", "n_citations": 55, "n_key_citations": 0, "score": 0, "title": "Photocorrosion inhibition of CdS based catalysts for photocatalytic overall water splitting.", "venue": "Nanoscale", "year": 2020 }, { "abstract": "Abstract Photocatalysts made of earth abundant elements using simple fabrication methods are highly desirable for bacterial inactivation in practical applications. This study proved that the carbon based g C3N4 could act as an effective antagonist to the ubiquitous plant pathogen Rhizobium radiobacter with good photostability and reusability under visible light. The applying of g C3N4 efficiently improved the survivability of tobacco seedlings under the stress of R. radiobacter and showed no adverse effect on tobacco growth compared with the common metal based TiO2 and CdS photocatalysts. The systematic mechanism studies revealed that the photoinduced reactive species (RSs) were strongly involved in the photocatalytic bacterial inactivation process, with an effectiveness of h+ *O2 *OH H2O2 e 1O2. The direct contact between g C3N4 and bacterial cells was also essential for the effective bacterial inactivation. Although bacterial self protection system (SOD and CAT enzymes) functioned in the initial period, the accumulated RSs damaged cell membrane structure as well as membrane associated respiration and ATP synthesis ability, finally leading to the leakage of cellular building blocks (K+ TOC, DNA and RNA) and irreversible cell death. This study illustrated that the g C3N4 could be used as an ideal photocatalytic bactericide towards agriculture application to improve the plant resistance to pathogens with good biocompatibility and low cost.", "author_names": [ "Kemeng Xiao", "Tieyuan Liu", "Panqing Yin", "Xiaoning Ren", "Jun Liang", "Wugen Zhan", "Jianhua Zhang", "Bo Wang", "Po Keung Wong" ], "corpus_id": 224979573, "doc_id": "224979573", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Effective photocatalytic inactivation of the plant pathogen Rhizobium radiobacter by carbon based material: Mechanism and agriculture application", "venue": "", "year": 2020 }, { "abstract": "Cadmium Sulfide (CdS) is one of the highly photo sensitive and good semiconductor material of II VI group elements. Cadmium Sulfide (CdS) have different applications in optoelectronic devices like solar cells, photo detectors etc. In the present work CdS thin films were deposited on ultrasonically cleaned glass substrates using sol gel spin coating technique. The structural, optical and surface morphologies of CdS thin films were investigated by X ray diffraction (XRD) analysis, UV Visible Spectrum analysis, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) The Crystallographic Structure was determined from XRD analysis. It reveals the films were Crystallized in Hexagonal phase with (0 0 2) plane. The Band gap is calculated from Tauc's plot from Absorbance Spectrum. The determined Band gap values of CdS thin films Decreases with Increase in Annealing Temperature. AFM gives the roughness of the CdS films. SEM studies reveals that the grains are spherically shaped and distributed uniformly over the entire surface of the glass substrate. Electrical Properties of the Cadmium Sulfide (CdS) thin films were studied with I V measurement system", "author_names": [ "B Ravi Kumar", "S R Meher" ], "corpus_id": 56561619, "doc_id": "56561619", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Cadmium Sulfide (CdS) Based Thin Films for Photo Sensing Application", "venue": "", "year": 2016 }, { "abstract": "The invention belongs to the field of functional nano materials, sensing analysis and environment analysis, and provides a preparation method and application of a photoelectrochemical sensor for sensitively detecting Cd based on a ZnO and CdS compound semiconductor material. The preparation method comprises the steps of based on an ITO electrode as a substrate, inoculating ZnO seed crystal to the ITO electrode, and depositing CdS on the ITO electrode having crystallized ZnO through an electro deposition method based on NaS2SO3 as a sulfur source, Cd in an environment sample as a cadmium source and EDTA as a stabilizing agent, so that the photoelectric signal is greatly enhanced, the detection range is 0.01 5.0mmol/L, and the detection limit is 5micromol/L.", "author_names": [ "" ], "corpus_id": 139159547, "doc_id": "139159547", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Preparation method and application of photoelectrochemical sensor for sensitively detecting Cd based on ZnO and CdS compound semiconductor material", "venue": "", "year": 2015 }, { "abstract": "Abstract A facile, efficient and novel strategy was developed for the preparation of reduced Graphene Oxide/Carbon Dots (rGO/CDs) by electrospinning and annealing of an organic polymer. In the present investigation, rGO/CDs was prepared from poly (vinylidene fluoride co hexafluoropylene) [P(VDF HFP] based nanofiber fabricated via electrospinning technique followed by calcination. Formation of rGO/CDs was confirmed with the help of X Ray diffraction (XRD) FTIR and XPS analyses indicate the presence of C and O in nanostructure, which demonstrates that this method can efficiently convert calcined polymeric nanofiber into rGO/CDs. FE SEM micrographs reveal the morphological changes of the nanofiber membrane during the calcination process. The material shows excellent property to detect dopamine (DA) In the case of CV, a linear relationship for the DA concentration is observed in the range of 0.5uM to 20uM and, linear regression equation is y 8.32667x 0.0524 through correlation coefficient (R2) 0.99174, with a detection limit of 1.41 uM. All the electrochemical measurements were performed in 0.1 M phosphate buffer solution (PBS) of pH 7.2 as a supporting electrolyte. Therefore, the rGO/CDs/GCE electrode can be effectively applied to the quantitative analysis of DA.", "author_names": [ "Vinit Sharma", "Gun Anit Kaur", "Neeraj Gupta", "Mamta Shandilya" ], "corpus_id": 225225286, "doc_id": "225225286", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Growth mechanism of rGO/CDs by electrospun calcination process: Structure and application", "venue": "", "year": 2020 }, { "abstract": "Sewage discharge produced by homes and industries contains both oil and water soluble components. In order to remove oil from water, materials with specific wettability can be used; however, these materials cannot remove dissolved contaminants from water. In this research, we prepared a superhydrophobic CdS cotton for water purification. This material has the ability to adsorb different types of oil due to its non wettability (WCA 152deg) Moreover, its response behavior towards visible light enables it to remove water soluble pollutants as well. The highest oil absorption rate of superhydrophobic CdS cotton is nearly 30 times, and it can absorb light below 564 nm and produce *OH to degrade water soluble pollutants. Finally, based on Mott Schottky curve, the position of Fermi energy level was determined 0.55 eV) Also, the positions of valence and conduction bands were calculated based on the analysis of band gap which helps in proving photoelectric response characteristics.", "author_names": [ "Bo Ge", "Guina Ren", "Pengfei Zhao", "Chuanyu Jin", "Wenzhi Li", "Zhenzhong Zhang" ], "corpus_id": 209940957, "doc_id": "209940957", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Preparation of superhydrophobic CdS cotton using visible light response and its application for the control of water pollution", "venue": "Science China Technological Sciences", "year": 2019 }, { "abstract": "Photocatalytic degradation of pollutants based on semiconductor quantum dots (QDs) can be applied in wastewater purification methods. However, application of free QDs was associated with some difficulties, such as oxidation and agglomeration of QDs and difficulties in separation. As a solution to these problems, we have proposed the production of mesoporous SBA 15 supported CdS quantum dots as a more stable photo catalyst. The efficiency of these prepared nanocomposites was examined for photocatalytic degradation of Alizarin, as an organic pollutant. Results demonstrated that the proposed material is a promising catalyst for photocatalytic degradation of dyes in wastewaters. The kinetic and adsorption isotherms of photocatalytic degradation process were also studied and a detailed mechanism proposed for degradation process. The proposed mechanism was studied using free radicals trapping experiments; results demonstrated that the \\bullet \\text{O}}_{2} $O2 radicals are active intermediates and have an important role in the photodegradation mechanism.", "author_names": [ "Abdolraouf Samadi-Maybodi", "Mohammad-Rasool Sadeghi-Maleki" ], "corpus_id": 105188874, "doc_id": "105188874", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Preparation of Mesoporous SBA 15 Supported CdS Quantum Dots and Its Application for Photocatalytic Degradation of Organic Pollutants in Aqueous Media", "venue": "Journal of Inorganic and Organometallic Polymers and Materials", "year": 2018 }, { "abstract": "Abstract Cadmium sulphide (CdS) is the n type, wide band gap II VI semiconducting material by offering applications in photovoltaics. Among the range of applications offered by CdS thin films, it has found application as a window layer in second generation solar cells by creating photon traps, thereby quantum efficiency. Closed space sublimation (CSS) offers a trivial yet effective approach for the synthesis of thin films for solar cell applications at moderate temperatures. CdS thin films of controlled thicknesses were synthesized by CSS technique by varying exposure time. X rays diffraction data of these thin films revealed polycrystalline nature with a preferred orientation along (002) direction. The scanning electron microscopy (SEM) based morphological studies showed grain size variation with an increase in thickness of deposited thin films in the range of 300 500 nm. The electrical studies revealed high resistivity of the order of 106 O cm. Spectrophotometric studies performed for CdS thin films concluded with the calculation of the optical parameters such as refractive index, absorption coefficient employing the Swanepoel model, and energy band gap of ~2.42 eV using the Tauc relation in addition to thin film thickness confirmation. The variations in thickness affect the structure, surface, optical (Khan et al. 2018) electrical properties.", "author_names": [ "Waqar Mahmood", "Junaid Ali", "Iqra Zahid", "Andrew G Thomas", "Anwar Ul Haq" ], "corpus_id": 125502279, "doc_id": "125502279", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Optical and electrical studies of CdS thin films with thickness variation", "venue": "", "year": 2018 }, { "abstract": "Abstract Cd substituted tetrahedrite Cu10Cd2Sb4S13 (TH Cd) monograin powders were synthesized in molten CdI2 (as flux) with the aim to implement these materials as absorbers in monograin layer solar cells. Our study focuses on the influence of technological parameters, like the initial composition of precursors, the amount of CdI2 flux and temperature of synthesis, on the elemental and phase composition and on the size and shape of powder crystals. Based on energy dispersive X ray spectroscopy and X ray diffraction investigations, mainly single phase tetrahedrite with a composition close to the stoichiometry of Cu10Cd2Sb4S13 was formed at 480 and 495 degC. It was found that incorporation of Cd from CdI2 into formed crystals rised with increasing amount of CdI2 flux if no other Cd source (CdS) was used. It was shown for the first time that there are peaks at 94 97 cm 1 and 108 112 cm 1 in the Raman spectra of Cu12Sb4S13 and Cu10Cd2Sb4S13, respectively. Monograin powders grown at 495 degC were used as absorber material in monograin layer solar cells with a structure of ZnO/CdS/Cu10Cd2Sb4S13/graphite. The efficiency of the first TH Cd monograin layer solar cell was 0.14% The effective band gap value of Cu10Cd2Sb4S13 absorber was determined as 1.3 eV.", "author_names": [ "Fairouz Ghisani", "Kristi Timmo", "Mare Altosaar", "Jaan Raudoja", "Valdek Mikli", "M Pilvet", "M Kauk-Kuusik", "Maarja Grossberg" ], "corpus_id": 213872894, "doc_id": "213872894", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Synthesis and characterization of tetrahedrite Cu10Cd2Sb4S13 monograin material for photovoltaic application", "venue": "", "year": 2020 }, { "abstract": "Abstract This paper reports an inclusive study of synthesis and characterization of quantum dots CdS embedded Pb0.85La0.15TiO3 (PLT15) dielectric nanocomposite materials for application in thin film quantum dots solar cells (QDSSc) We have synthesized dielectric materials which act as a strong field effect passivation, screened columbic attraction, back reflector and recombination inhibitor for solar cell fabrication. This material was deposited on FTO/TiO2 layer with a uniform mixed layer of nanorod (CdS) nanoparticles (PLT15) which result in an increase in the SCs efficiency by times higher from the reference value. By adding dielectric materials in a prototype solar cell, an enhancement of 6.32 mA/cm2 in short circuit current and an absolute value of 4.5% enhancement in overall conversion efficiency are achieved. In particular, synthesis of materials, fabrication, structural, optical, electrical and stability of the prototype SCs are examined thoroughly. We also performed a detailed investigation of aging on the main characteristics of solar cells, such as efficiency, fill factor, short circuit current and open circuit voltage. It was observed that due to its cost effectiveness, stability, and enhance efficiency, this dielectric based hybrid thin film solar cells have high potential to be applied in industry in the near future.", "author_names": [ "Argha Dey", "Poulami Karan", "Abhinanda Sengupta", "Sk Abdul Moyez", "Poulomi Sarkar", "Subhasish Basu Majumder", "Debabrata Pradhan", "Subhasish Roy" ], "corpus_id": 126417707, "doc_id": "126417707", "n_citations": 9, "n_key_citations": 1, "score": 0, "title": "Enhanced charge carrier generation by dielectric nanomaterials for quantum dots solar cells based on CdS TiO2 photoanode", "venue": "", "year": 2017 } ]

[ { "abstract": "Whole eras of technical progress and economic growth appear to be driven by a few key technologies, which we call General Purpose Technologies (GPT's) Thus the steam engine and the electric motor may have played such a role in the past, whereas semiconductors and computers may be doing as much in our era. GPT's are characterized by pervasiveness (they are used as inputs by many downstream sectors) inherent potential for technical improvements, and innovational complementarities' meaning that the productivity of RD on the other hand this phenomenon makes it difficult for a decentralized economy to fully exploit the growth opportunities offered by evolving GPT's. In particular; if the relationship between the GPT and its users is limited to arms length market transactions, there will be \"too little, too late\" innovation in both sectors. Likewise, difficulties in forecasting the technological developments of the other side may lower the rate of technical advance of all sectors. Lastly, we show that the analysis of GPT's has testable implications in the context of R&D and productivity equations, that can in principle be estimated.", "author_names": [ "Timothy F Bresnahan", "Manuel Trajtenberg" ], "corpus_id": 221989035, "doc_id": "221989035", "n_citations": 91, "n_key_citations": 10, "score": 1, "title": "General Purpose Technologies \"Engines of Growth?\"", "venue": "", "year": 1992 }, { "abstract": "Since Bresnahan and Trajitenberg's original 1995 article on 'General Purpose Technology (GPT) Engines of Growth' the concept of GPT has slowly but steadily influenced the literature on business ICT (information and communication technology) adoption. In considering business ICT, within the framework of GPT allows to focus on the externalities in ICT adoption which poses challenges for policy and society as a whole. In the literature, these externality benefits of business ICT have rarely been examined. In this context, the article provides a survey of recently published empirical studies (from 2004 to 2013) citing the original article of Bresnahan and Trajenberg. In using the science citation index and citations derived from Google Scholar, we found 1090 articles fulfilling these criteria; from these articles just 57 studies provided some empirical estimation of the productivity impact of ICT. Our survey indicates if GPT refers to whole range of ICT, this might generate misleading results. In general, our results indicate a shift in the discussion on GPT focusing on business ICT. The literature demonstrates that with the availability of better data increasingly a better distinction between infrastructure technologies and applications should be used. While infrastructure technologies are uniformly adopted among small and large enterprises, the adoption of applications is a more complex phenomenon. Although some authors argue that there is a productivity impact of ICT, this impact is mediated by employment, wage and size variables. In particular, the adoption of business ICT within small and medium sized enterprises (SMEs) has rarely been examined.", "author_names": [ "S Sadaf Bashir", "Bm Bert Sadowski" ], "corpus_id": 58917894, "doc_id": "58917894", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "General Purpose Technologies: A Survey, a Critique and Future Research Directions", "venue": "", "year": 2014 }, { "abstract": "This dissertation tackles the different aspects of the creation and transmission of (new) knowledge in the context of the characteristics of a general purpose technology (GPT) Particular emphasis is put on the role of the composition of knowledge as well as the corresponding (presumed) knowledge spillovers on the one hand and on the concrete impact of collaboration and knowledge sharing in innovator networks on the other hand. The thesis offers a coherent literature review in its first part, analysing the theoretical role of knowledge for innovation and growth as well as the role of knowledge diffusion and sharing. Although the development of GPTs is particularly knowledgeand innovation intensive and GPTs are found to be 'engines of growth' the role of knowledge for innovation in GPTs has not been distinctive subject to investigation yet. Therefore, the two mentioned sets of research questions were tackled empirically in this thesis using the showcase example of nanotechnology. Nanotechnology is argued to be the key technology of the future, and empirical analyses in this thesis using patent and publication data provided evidence that there is sensible reason to consider nanotechnology as GPT. The first array of research questions is concerned with the role of local knowledge composition and spillovers for the development of nanotechnology. Two different approaches capture these issues. The first one investigates how the characteristics of the regional technological nano knowledge base as approximated (mainly) by patents influence the creation of new nanoknowledge. Panel negative binomial regression analyses are employed to disentangle the effects. The second approach captures the performance of nano firms depending on the local endowment with knowledge as investigated by means of OLS and fixed effects panel analyses. The central finding is that the regional endowment with knowledge impacts the development of nanotechnology. Concerning the composition of the knowledge bases, evidence suggests that specialisation and diversity are positively impacting innovation in nanotechnology. More particularly both are necessary to support nanotechnology's characteristics both as high technology and as GPT. Focusing on the role of collaboration and knowledge sharing in networks, the second array of research questions is tackled by another two analyses. One analysis focuses on the development of the role of collaboration and networking. The means of social network analysis of German nanotechnology patents' co contributorship networks shed light on the relationship between collaboration, the efficiency of the networks and the technological overlap (and hence the potential for cooperation) and the development of nanotechnology. The second analysis more particularly puts an emphasis on the factors that impact the generality of a patent. Therefore variables such as intensity of collaboration, access to knowledge, experience and overlap of technological background are included into fractional logit analyses. Findings include that the performance of a GPT can be enhanced through collaboration by offering efficient means for the organisation and coordination of knowledge sharing and knowledge spillovers and by fostering an increase in the technology's generality level due to knowledge sharing in teams and networks.", "author_names": [ "Nina Teichert" ], "corpus_id": 65124642, "doc_id": "65124642", "n_citations": 5, "n_key_citations": 2, "score": 0, "title": "Innovation in General Purpose Technologies How Knowledge Gains when It Is Shared", "venue": "", "year": 2013 }, { "abstract": "Since Bresnahan and Trajitenberg's original 1995 article on 'General Purpose Technology (GPT) Engines of Growth' the concept of GPT has slowly but steadily influenced the literature on business ICT (information and communication technology) adoption. In considering business ICT, within the framework of GPT allows to focus on the externalities in ICT adoption which poses challenges for policy and society as a whole. In the literature, these externality benefits of business ICT have rarely been examined. In this context, the article provides a survey of recently published empirical studies (from 2004 to 2013) citing the original article of Bresnahan and Trajenberg. In using the science citation index and citations derived from Google Scholar, we found 1090 articles fulfilling these criteria; from these articles just 57 studies provided some empirical estimation of the productivity impact of ICT. Our survey indicates if GPT refers to whole range of ICT, this might generate misleading results. In general, our results indicate a shift in the discussion on GPT focusing on business ICT. The literature demonstrates that with the availability of better data increasingly a better distinction between infrastructure technologies and applications should be used. While infrastructure technologies are uniformly adopted among small and large enterprises, the adoption of applications is a more complex phenomenon. Although some authors argue that there is a productivity impact of ICT, this impact is mediated by employment, wage and size variables. In particular, the adoption of business ICT within small and medium sized enterprises (SMEs) has rarely been examined. 1 Corresponding author: S.Bashir@tue.nl", "author_names": [ "S Sadaf Bashir", "Bert M Sadowski" ], "corpus_id": 89606933, "doc_id": "89606933", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "1 General Purpose Technologies A survey a critique and future research directions", "venue": "", "year": 2014 }, { "abstract": "This paper presents a critique of the General Purpose Technology (GPT) framework. It argues that the GPT framework is fundamentally flawed as an approach to understanding growth as it focuses on what are input production technologies (hereafter input technologies) and not on the associated primary inputs and resulting outputs. Computers don't produce output; rather, they produce information which is necessary for the production of output. Dynamos don't produce output, rather they transform prime movers (steam, hydraulics, fossil fuels) into electricity which is transmitted to machines that ultimately produce output. Steam engines don't produce output; rather, they too transmit prime movers (fossil fuels) into output. The problem with the GPT framewoek lies with the implicit assumption that there exists a one to one relationship between the intermediate input and the primary input. We will show that this assumption was violated in all three classic GPT cases, which explains what Paul Davd referred to as the \"electricity paradox\" and what Robert Solow referred to as the \"information paradox.\" We then proceed to present an alternative framework based on the concept of enabling technologies.", "author_names": [ "Bernard C Beaudreau" ], "corpus_id": 114646187, "doc_id": "114646187", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Critique of the General Purpose Technology Framework", "venue": "", "year": 2016 }, { "abstract": "We present a dynamic, non scale general equilibrium model with two human capital types where Schumpeterian R&D and human capital accumulation are the engines of growth and wage inequality. In particular, wage inequality is encouraged by relative changes in supply and demand of both human capital types. Relative supply restricts employed human capital levels. Relative demand is instantly affected by a new general purpose technology and, as in the skill biased technological change literature, by technological knowledge bias. By considering substitutability between technologies and complementarity between inputs, the bias is driven by the price channel (not by the market size channel) and is affected by human capital accumulation.", "author_names": [ "Oscar Afonso" ], "corpus_id": 154992780, "doc_id": "154992780", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Growth and Wage Inequality in a Scale Independent Model with R&D and Human Capital Accumulation", "venue": "", "year": 2010 }, { "abstract": "The model we propose in this paper is an extension of the one described in Freeman et al. [Freeman, S. Hong, D. and Peled, D. (1999) Endogenous Cycles and Growth with Indivisible Technological Developments. Review of Economics Dynamics, 2, 403 432] In our model, we incorporate the process of diffusion of major innovations and analyze macroeconomic effects on consumption, capital and aggregate output. Following Bresnahan and Trajtenberg [Bresnahan, T. and Trajtenberg, M. (1995) General Purpose Technologies: Engines of Growth? Journal of Econometrics, 65, 83 108. Helpman [Helpman, E. (ed. (1998) General Purpose Technologies and Economic Growth. MIT Press] and Lipsey et al. [Lipsey, R.G. Carlaw, K. and Bekar, C. (2005) Economic Transformations: General Purpose Technologies and Long Term Economic Growth. Oxford University Press. we assimilate major innovations with the emergence of certain GPTs, and we suggest that the diffusion process for these technologies, at a large scale, might follow an S shaped pattern. The proposed model presents optimum stationary solutions which are cyclical and have a wave dynamic within each cycle. The cycles are characterized by certain co movements in consumption, R&D investment, capital accumulation and output. Consideration of the innovation diffusion process highlights new aspects of endogenous cycles and long run growth.", "author_names": [ "Julio Sanchez-Choliz", "Francisco Fatas-Villafranca", "Gloria Jarne", "Isabel Perez-Grasa" ], "corpus_id": 154073375, "doc_id": "154073375", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "ENDOGENOUS CYCLICAL GROWTH WITH A SIGMOIDAL DIFFUSION OF INNOVATIONS", "venue": "", "year": 2008 }, { "abstract": "Google is an American multinational technology company which specializes in internet related services and products. The products and services offered by Google include online advertising technologies, search, cloud computing, and software. Google's ownership structure consists of 95% equity and 5% debt. Google's board of directors have authorized three classes of stock Class A, Class B common stock, and Class C capital stock. The continuing shift from an offline to online world has contributed to the growth of Google's business. Google generate revenue primarily by delivering both performance advertising and brand advertising. Google have many competitors in different industries, including general purpose search engines and information services, vertical search engines and e commerce websites, social networks, providers of online products and services, other forms of advertising. Acquisition is an important strategy of growth for Google. Google has emerged as the one of the biggest and most successful acquirers in the technology industry. Google went public on August 19, 2004.", "author_names": [ "Rajesh Kumar" ], "corpus_id": 168560116, "doc_id": "168560116", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wealth creation analysis of Google", "venue": "", "year": 2017 }, { "abstract": "This paper presents the latest update for historical scaling dynamics research including new technoloies such as general purpose technologies (e.g. steam engines) and small end use technologies (e.g.,cellphones, e bikes) Scaling refers to technology growth that is rapid and extensive, occurring at different levels, both unit and industry. It also studies the importance of the formative phase in the historical diffusion of energy technologies. So, what are the characteristics of the formative phase in the case of fast and intense adoptions? What is the infuence of the formative phase in the overall diffusion? Empirical analysis uses logistic models to exlore the growth of energy technologies observed historically. The formative phase is defined here as the early stage of diffusion before technology up scales at unit level; the operational critera adoped is that formative phase ends when diffusion reaches 10% of cumulative total unit numbers. The hisorical evidence confirms that larger transitions require more time for experimentation and maturation in the formative periods, especially in the case of complex innovations with high infrastrcture needs. In addition, small size technologies with high turnover rates present the fastest diffusion. Moreresearch is needed to refine the definition of the moment when the technology completes the formativ phase and acquires enough maturity to pass on to mass commercialization. KEYWRODS: technological change; innovation; economies of scale; logistic growth; formative phases", "author_names": [ "Nuno Bento" ], "corpus_id": 112128372, "doc_id": "112128372", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "New Evidence in Technology Scaling Dynamics and the Role of the Formative Phase", "venue": "", "year": 2013 }, { "abstract": "BackgroundWith the growth of biological data in volume and heterogeneity, web search engines become key tools for researchers. However, general purpose search engines are not specialized for the search of biological data.DescriptionHere, we present an approach at developing a biological web search engine based on the Semantic Web technologies and demonstrate its implementation for retrieving gene and protein centered knowledge. The engine is available at http:/www.integromedb.org.ConclusionsThe IntegromeDB search engine allows scanning data on gene regulation, gene expression, protein protein interactions, pathways, metagenomics, mutations, diseases, and other gene and protein related data that are automatically retrieved from publicly available databases and web pages using biological ontologies. To perfect the resource design and usability, we welcome and encourage community feedback.", "author_names": [ "Michael Baitaluk", "Sergey Kozhenkov", "Yulia Dubinina", "Julia V Ponomarenko" ], "corpus_id": 15615120, "doc_id": "15615120", "n_citations": 12, "n_key_citations": 2, "score": 0, "title": "IntegromeDB: an integrated system and biological search engine", "venue": "BMC Genomics", "year": 2011 } ]

[ { "abstract": "A pressure induced topological quantum phase transition has been theoretically predicted for the semiconductor bismuth tellurohalide BiTeI with giant Rashba spin splitting. In this work, evolution of the electrical transport properties in BiTeI and BiTeBr is investigated under high pressure. The pressure dependent resistivity in a wide temperature range passes through a minimum at around 3 GPa, indicating the predicted topological quantum phase transition in BiTeI. Superconductivity is observed in both BiTeI and BiTeBr, while resistivity at higher temperatures still exhibits semiconducting behavior. Theoretical calculations suggest that superconductivity may develop from the multivalley semiconductor phase. The superconducting transition temperature, Tc increases with applied pressure and reaches a maximum value of 5.2 K at 23.5 GPa for BiTeI (4.8 K at 31.7 GPa for BiTeBr) followed by a slow decrease. The results demonstrate that BiTeX (X I, Br) compounds with nontrivial topology of electronic states display new ground states upon compression.", "author_names": [ "Yanpeng Qi", "Wujun Shi", "Pavel G Naumov", "Nitesh Kumar", "Raman Sankar", "Walter Schnelle", "Chandra Shekhar", "F C Chou", "Claudia Felser", "Binghai Yan", "Sergey A Medvedev" ], "corpus_id": 2043282, "doc_id": "2043282", "n_citations": 215, "n_key_citations": 0, "score": 0, "title": "Topological Quantum Phase Transition and Superconductivity Induced by Pressure in the Bismuth Tellurohalide BiTeI.", "venue": "Advanced materials", "year": 2017 }, { "abstract": "ZrSiS has recently gained attention due to its unusual electronic properties: nearly perfect electron hole compensation, large, anisotropic magneto resistance, multiple Dirac nodes near the Fermi level, and an extremely large range of linear dispersion of up to 2 eV. We have carried out a series of high pressure electrical resistivity measurements on single crystals of ZrSiS. Shubnikov de Haas measurements show two distinct oscillation frequencies. For the smaller orbit, we observe a change in the phase of 0.5, which occurs between 0.16 0.5 GPa. This change in phase is accompanied by an abrupt decrease of the cross sectional area of this Fermi surface. We attribute this change in phase to a possible topological quantum phase transition. The phase of the larger orbit exhibits a Berry phase of pi and remains roughly constant up to 2.3 GPa. Resistivity measurements to higher pressures show no evidence for pressure induced superconductivity to at least 20 GPa.", "author_names": [ "Derrick VanGennep", "Th Paul", "C W Yerger", "Samuel T Weir", "Yogesh K Vohra", "James J Hamlin" ], "corpus_id": 119450324, "doc_id": "119450324", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Possible pressure induced topological quantum phase transition in the nodal line semimetal ZrSiS", "venue": "Physical Review B", "year": 2019 }, { "abstract": "We report on the discovery of a quantum tri critical point (QTP) separating a line of first order topological quantum phase transitions from a continuous transition regime in a strongly correlated one dimensional lattice system. Specifically, we study a fermionic four leg ladder supporting a symmetry protected topological phase in the presence of on site interaction, which is driven towards a trivial gapped phase by a nearest neighbor interaction. Based on DMRG simulations, we show that, as a function of the interaction strength, the phase transition between the topological and the trivial phase switches from being continuous to exhibiting a first order character. Remarkably, the QTP as well as the first order character of the topological transition in the strongly correlated regime are found to clearly manifest in simple local observables.", "author_names": [ "Simone Barbarino", "Giorgio Sangiovanni", "Jan Carl Budich" ], "corpus_id": 119048202, "doc_id": "119048202", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "First order topological quantum phase transition in a strongly correlated ladder", "venue": "Physical Review B", "year": 2019 }, { "abstract": "Since the seminal ideas of Berezinskii, Kosterlitz and Thouless, topological excitations have been at the heart of our understanding of a whole novel class of phase transitions. In most cases, those transitions are controlled by a single type of topological objects. There are, however, some situations, still poorly understood, where two dual topological excitations fight to control the phase diagram and the transition. Finding experimental realizations of such cases is thus of considerable interest. We show here that this situation occurs in BaCo2V2O8, a spin 1/2 Ising like quasi one dimensional antiferromagnet, when subjected to a uniform magnetic field transverse to the Ising axis. Using neutron scattering experiments, we measure a drastic modification of the quantum excitations beyond a critical value of the magnetic field. This quantum phase transition is identified, through a comparison with theoretical calculations, to be a transition between two different types of solitonic topological object, which are captured by different components of the dynamical structure factor.A neutron scattering study of an Ising like quasi one dimensional antiferromagnet, BaCo2V2O8, reveals a topological quantum phase transition when it is subjected to a transverse magnetic field.", "author_names": [ "Quentin Faure", "Shintaro Takayoshi", "Sylvain Petit", "Virginie Simonet", "S Raymond", "L -P Regnault", "Martin Boehm", "Jonathan S White", "Martin Mansson", "Christian Ruegg", "Pascal Lejay", "Benjamin Canals", "Thomas Lorenz", "Shunsuke C Furuya", "Thierry Giamarchi", "Beatrice Grenier" ], "corpus_id": 118959342, "doc_id": "118959342", "n_citations": 40, "n_key_citations": 1, "score": 0, "title": "Topological quantum phase transition in the Ising like antiferromagnetic spin chain BaCo2V2O8", "venue": "", "year": 2017 }, { "abstract": "We report a continuous phase transition between quantum anomalous Hall and trivial insulator phases in a magnetic topological insulator upon magnetization rotation. The Hall conductivity transits from one plateau of quantized Hall conductivity $e^2/h$ to the other plateau of zero Hall conductivity. The transition curves taken at various temperatures cross almost at a single point, exemplifying the critical behavior of the transition. The slope of the transition curves follows a power law temperature dependence with a critical exponent of 0.61$ This suggests a common underlying origin in the plateau transitions between the QAH and quantum Hall systems, which is a percolation of one dimensional chiral edge channels.", "author_names": [ "Minoru Kawamura", "Masataka Mogi", "Ryutaro Yoshimi", "Atsushi Tsukazaki", "Yusuke Kozuka", "Kei S Takahashi", "Masashi Kawasaki", "Yoshinori Tokura" ], "corpus_id": 62829119, "doc_id": "62829119", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Topological quantum phase transition in magnetic topological insulator upon magnetization rotation", "venue": "", "year": 2018 }, { "abstract": "Topological insulators constitute a new phase of matter protected by symmetries. Time reversal symmetry protects strong topological insulators of the Z2 class, which possess an odd number of metallic surface states with dispersion of a Dirac cone. Topological crystalline insulators are merely protected by individual crystal symmetries and exist for an even number of Dirac cones. Here, we demonstrate that Bi doping of Pb1 xSnxSe (111) epilayers induces a quantum phase transition from a topological crystalline insulator to a Z2 topological insulator. This occurs because Bi doping lifts the fourfold valley degeneracy and induces a gap at \\bar \\Gamma $G, while the three Dirac cones at the \\bar{\\rm M}$M points of the surface Brillouin zone remain intact. We interpret this new phase transition as caused by a lattice distortion. Our findings extend the topological phase diagram enormously and make strong topological insulators switchable by distortions or electric fields.Transitions between topological phases of matter protected by different symmetries remain rare. Here, Mandal et al. report a quantum phase transition from a topological crystalline insulator to a Z2 topological insulator by doping Bi into Pb1 xSnxSe (111) thin films.", "author_names": [ "Partha Sarathi Mandal", "Gunther Springholz", "Valentine V Volobuev", "Ondrej Caha", "Andrei Varykhalov", "Evangelos Golias", "G Bauer", "Oliver Rader", "Jaime Sanchez-Barriga" ], "corpus_id": 3283360, "doc_id": "3283360", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "Topological quantum phase transition from mirror to time reversal symmetry protected topological insulator", "venue": "Nature Communications", "year": 2017 }, { "abstract": "An attempt is made to understand the topological quantum phase transition, emergence of relativistic modes and local topological order of light in a strongly interacting light matter system. We study this system, in a one dimensional array of nonlinear cavities. Topological quantum phase transition occurs with massless excitation only for the finite detuning process. We present a few results based on the exact analytical calculations along with the physical explanations. We observe the emergence of massive Majorana fermion mode at the topological state, massless Majorana Weyl fermion mode during the topological quantum phase transition and Dirac fermion mode for the non topological state. Finally, we study the quantized Berry phase (topological order) and its connection to the topological number (winding number)", "author_names": [ "Sujit Sarkar" ], "corpus_id": 23760770, "doc_id": "23760770", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Topological Quantum Phase Transition and Local Topological Order in a Strongly Interacting Light Matter System", "venue": "Scientific Reports", "year": 2017 }, { "abstract": "When a quantum phase transition is crossed in finite time, critical slowing down leads to the breakdown of adiabatic dynamics and the formation of topological defects. The average density of defects scales with the quench rate following a universal power law predicted by the Kibble Zurek mechanism. We analyze the full counting statistics of kinks and report the exact kink number distribution in the transverse field quantum Ising model. Kink statistics is described by the Poisson binomial distribution with all cumulants exhibiting a universal power law scaling with the quench rate. In the absence of finite size effects, the distribution approaches a normal one, a feature that is expected to apply broadly in systems described by the Kibble Zurek mechanism.", "author_names": [ "Adolfo del Campo" ], "corpus_id": 51736461, "doc_id": "51736461", "n_citations": 30, "n_key_citations": 3, "score": 0, "title": "Universal Statistics of Topological Defects Formed in a Quantum Phase Transition.", "venue": "", "year": 2018 }, { "abstract": "The quantum phase transition between two clean, non interacting topologically distinct gapped states in three dimensions is governed by a massless Dirac fermion fixed point, irrespective of the underlying symmetry class, and this constitutes a remarkably simple example of superuniversality. For a sufficiently weak disorder strength, we show that the massless Dirac fixed point is at the heart of the robustness of superuniversality. We establish this by considering both perturbative and nonperturbative effects of disorder. The superuniversality breaks down at a critical strength of disorder, beyond which the topologically distinct localized phases become separated by a delocalized diffusive phase. In the global phase diagram, the disorder controlled fixed point where superuniversality is lost, serves as a multicritical point, where the delocalized diffusive and two topologically distinct localized phases meet and the nature of the localization delocalization transition depends on the underlying symmetry class. Based on these features we construct the global phase diagrams of noninteracting, dirty topological systems in three dimensions. We also establish a similar structure of the phase diagram and the superuniversality for weak disorder in higher spatial dimensions. By noting that $1/r^2$ power law correlated disorder acts as a marginal perturbation for massless Dirac fermion in any spatial dimension $d$ we have established a general renormalization group framework for addressing disorder driven critical phenomena for fixed spatial dimension $d 2$", "author_names": [ "Pallab Goswami", "Sudip Chakravarty" ], "corpus_id": 118503313, "doc_id": "118503313", "n_citations": 14, "n_key_citations": 1, "score": 0, "title": "Superuniversality of topological quantum phase transition and global phase diagram of dirty topological systems in three dimensions", "venue": "", "year": 2017 }, { "abstract": "We investigate the quantum phase transition of the Su Schrieffer Heeger (SSH) model by inspecting the two site entanglements in the ground state. It is shown that the topological phase transition of the SSH model is signified by a nonanalyticity of local entanglement, which becomes discontinuous for finite even system sizes, and that this nonanalyticity has a topological origin. Such a peculiar singularity has a universal nature in one dimensional topological phase transitions of noninteracting fermions. We make this clearer by pointing out that an analogous quantity in the Kitaev chain exhibiting the identical nonanalyticity is the local electron density. As a byproduct, we show that there exists a different type of phase transition, whereby the pattern of the two site entanglements undergoes a sudden change. This transition is characterised solely by quantum information theory and does not accompany the closure of the spectral gap. We analyse the scaling behaviours of the entanglement in the vicinities of the transition points.", "author_names": [ "Jaeyoon Cho", "Kun Woo Kim" ], "corpus_id": 19381574, "doc_id": "19381574", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Quantum Phase Transition and Entanglement in Topological Quantum Wires", "venue": "Scientific Reports", "year": 2017 } ]

[ { "abstract": "Two dimensional (2D) materials have begun to impact the field of semiconductor quantum optics through the demonstration of stable quantum emitters in both transition metal dichalcogenides [1] and hexagonal boron nitride (hBN) [2] Single photon emitters (SPE) in hBN are associated with atom like defects that confine electronic levels deep within the wide band gap. As recently reported, the emission energy of these emitters spans over a large spectral band [3] which presents a central problem for developing identical single photon sources. Furthermore, exfoliated hBN flakes show high background emission that reduces single photon purity. We propose a material processing based on ion irradiation and high temperature annealing that allows to reduce the broadband background emission and therefore to isolate individual defects, as shown in the photoluminescence map of Fig.1a. Our sample fabrication process sharply improves the single photon purity with g(2)(0) 0.077, and brightness with emission rate exceeding 107counts/sec at saturation (see Fig.1b) To investigate the wide span of the emission energy, we transfer hBN films, after sample treatment, onto a bendable substrate that allows us to controllably apply strain, confirming also that quantum emitters persist this transfer process. Fig.1c plots the emission spectra of two SPEs for compressive, tensile and no strain. These emitters show different tuning coefficients up to 6 meV per strain unit. The strain control of the emission wavelength and the reduced multi photon emission probability produce a tunable ultra bright room temperature single photon source with the advantages of 2D materials, including stretchability, heterogeneous device assembly and straightforward integration with photonic circuits [4]", "author_names": [ "Hyowon Moon", "Benjamin Lienhard", "Sajid Ali", "Marco M Furchi", "Michael P Walsh", "Dmitri K Efetov", "Pablo Jarillo-Herrero", "Michael J Ford", "Igor Aharonovich", "D Englund" ], "corpus_id": 13748998, "doc_id": "13748998", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Tuning the ultra bright quantum emission from atomic defects in hexagonal Boron Nitride", "venue": "", "year": 2017 }, { "abstract": "We are pushing forward the developmentof a pulsedmagnet that has a combined structure of magnet coils with a ceramic vacuum chamber, aiming to realize a small gap. The structure we are developing is that single turn air coils are implanted along the longitudinal axis in the cylindrical ceramic chamber wall with thickness of 5 mm. The ceramic wall works for separating the vacuum from the atmosphere, as well as holding the coil structures mechanically and the electrical insulation of coils. We achieved the continuous operation over 200 days, without any failure, of currentexcitation with 20 kV/7.7 kA pulse with 4 msec width and repetition of 1Hz, using the dipole type prototype with the bore radius of 30 mm and the magnetic length of 0.3 m in 2013, whilemaintaining the vacuumpressure less than 10 6 Pa. MERITS OF NARROW GAP MAGNET The performances which are required in common to all pulsed magnet system are fast, strong, and high repeating pulsed magnetic field characteristics. In order to achieve these performances, there are two approaches. First one is developing a high power and high repetition pulsed power supply. Second one is reducing the power supply load as low as possible. The load reduction is an important issue. Because, if we try to achieve these performances without decreasing the load, the power supply system will have a large body size, consequently, need a huge installation space and give a restriction to the installation place of the system. One of the best solutions to lower the power supply load is reduce themagnet pole gap. The kick angle is determined by the magnetic filed strength and field length. By the increased magnetic field with reducing the pole gap, the field length becomes shorter while keeping the kick angle the same. As a result, the coil inductance, hence the pulsed power supply load, become small. The low coil inductance is effective to achieve short pulse width and high repetition rate, in addition, to make the power supply small. The compact magnet and small power supply give the flexibility for setting position in an accelerator, making the kick efficiency optimum with the appropriate beta function value position. Compact pulsed magnet with a narrow gap will fit to the future light source ring like generating diffraction limit synchrotron radiation [1] Because the storage ring chamber size will be reduced in order to match the ultra low beam emittance and there is no enough space to install the pulsed mitsuda@spring8.or.jp magnet due to a large number of optical magnets. Additionally, it also will fit to small size storage rings that will require narrow installation spaces for these kinds of devices involving the injection kickers and correction kickers, and that have short revolution period requiring shorter pulse width. CERAMIC CHAMBER INTEGRATION DESIGN AND THE ADVANTAGE Figure 1: Design of dipole type CCIPM for the fabrication. In an ordinary pulsed magnet, a ceramic chamber is used as a beam duct to reduce the eddy current effect for a pulsed magnetic field. Usually, the ironor ferrite core is set up outside of the ceramic chamber so that its magnetic poles sandwich the ceramic chamber. In this case, the distance(=magnet gap) between a magnetic pole and the beam is decided by the ceramic chamber bore radius, chamber thickness and clearance between the chamber and the pole. It is impossible to close the gap to the beam less than this restriction. On the other hand, in an air coil type pulsed magnet, the coil is set up on the surface of the ceramic chamber so that its poles hold a ceramic chamber, or inside of the ceramic chamber like a strip line kicker with complex supports. In the former case, the magnet gap is restricted by the ceramic chamber size. In the latter case, the complex support and coils cause an impedance unmatching of the beam wall current and increasing the chamber diameter to include the complex structures inside the chamber. To improve these insufficient aspects simultaneously, a ceramic chamber integrated type pulsed magnet was figured out. The structure we are developing is that single turn aircoils are implanted along the longitudinal axis in the cylindrical ceramic chamber wall with thickness of 5 mm. For a dipole type magnet, four metallic bars =coil) are totally implanted and one of bars is connected with another bars so that one pair of bars makes a coil. Implanting hole completely penetrates the chamber wall and is blocked up with the metallic bars. Figure 1 shows cross sectional view of Proceedings of IPAC2015, Richmond, VA, USA WEPMA049 7: Accelerator Technology T16 Pulsed Power Technology ISBN 978 3 95450 168 7 2879 Co py rig ht (c) 20 15 CC B Y3. 0 an d by th er es pe ct iv ea ut ho rs Figure 2: The distribution of a magnetic field strength with DC 1000A exciting current for the CCIPM design of Fig. 1. the dipole type design of the Ceramic Chamber Integrated Pulsed Magnet (CCIPM) We started actual development with KYOCERA Co. Ltd. in 2012. The bore radius is 30 mm and the magnet length =coil length) is 300 mm to match the SPring 8 bumpmagnet size. The coil is arranged at 30 degrees from the median plane in order to achieve the dipole field uniformity within 0.1% and maximize the field strength in the center of magnet. Figure 2 shows the field strength distribution for the actual coil arrangement of Fig. 1. The arc shape metal bars connect each pair of coils at the coil end along the ceramic circumference by the conductive epoxy resin in the prototype. By this way, the endcoils stand up naturally and the irregularity of the field at the magnet end is reduced by about 30 compared with no stand ups. One of the arc type bars works as a busbar which connects feeder lines from the pulsed power supply. There are two technical advantages by applying this CCIPM structure. First one is that the ceramic wall works for separating the vacuum from the atmosphere, as well as holding the coil structures mechanically and the electrical insulation of coils. By this structure, magnet pole edges can be set close to the inside diameter of the chamber. Seeing from inside of the ceramic chamber, the pole edges put on the inside surface of it and does not bulge from the surface level. Therefore, the pole edges are put close to the beam without disturbing the beam impedance. Second one is that the air coils are arranged around the circle on the ceramic inside surface to optimize the magnetic field strength and uniformity. There is no structural restriction to arrange the coil and not any complex coil supporting structure. As a whole, a pulsed magnet will be built with the extremely simple components which do not bulge inside and outside of the ceramic chamber. SUBJECTS TO THE FABRICATION The followings are important subjects about the CCIPM fabrication. Implanting multiple coils simultaneously along longitudinal axis over the 0.3 m. Keeping the super high vacuum tightwith the pressure of less than 1.3x10 11 Pa*m3/s. Enduring 0.1 MPa atmospheric pressure and magnetic field stress produced by the current more than 5 kA. Precisely arranging the coil with 10 mm along longitudinal axis. Ensuring the vacuum tightness under the thermal cycle stress up to 800 degrees. After the copper coils are implanted in the penetrated holes of the ceramic wall, it is bounded by silver brazing with a curing process at 800 degrees. It is the key technique in this development to implant the coil into the ceramic under the condition of the different thermal expansion rate along the longitudinal axis. To establish coil implanting technique, two development stages were taken as follows; firstly, optimization was done to reduce the residual strain, using the ceramic plate test piece, the coil shape and material, silver brazing volume, curing procedure and curing jig. Secondary, implanting technique established by test piece was expanded to the cylindrical ceramic chamber. In the Figure 3: A test piece sample with a typical huge crack. first stage, many vacuum leaks occurred by minute cracks around the coil end part inside and outside of the ceramic. Figure 3 shows the test piece and typical crack. The test pieces without vacuum leak experienced the curing process of 800 degrees again, and the vacuum tightness was confirmed to be kept. In the second stage, there was no product with vacuum leaks for both of two prototype products. However, when the flange sleeve was bounded to the ceramic by silver blazingwith 800 degrees in vertical posture, the silver solder which bounded coils was welded again and vacuumtightness broke. The newmethod that bind the ceramic and flange sleeves in horizontal posture was developedwith success. Finally, we succeeded in building the dipole type pulsed magnet prototype in 2013. The vacuum tightness under detection limit of 1.3x10 11 Pa*m3/s of He leak checker was achieved with flanges bound. RELIABILITY AND PERFORMANCES Continuous Operating We achieved the continuous operation over 252 days from 2013 to 2014 as shown in Table 1, without any failure, of current excitation by the current of 7.7 kA with 20 kV source with 4 m sec width and repetition of 1 Hz and with thermal cycle repetition. Figure 5 shows the conditioning setup before ribbon heaters were wrapped. The thermal cycle temperature was selected as from 30 degree celcius to 80 degrees. The 80 degrees was actually measured temperWEPMA049 Proceedings of IPAC2015, Richmond, VA, USA ISBN 978 3 95450 168 7 2880 Co py rig ht (c) 20 15 CC B Y3. 0 an d by th er es pe ct iv ea ut ho rs 7: Accelerator Technology T16 Pulsed Power Technology Figure 4: The inner surface view of the complicated CCIPM. ature on a ceramic chamber surface under the stored beam current of 100 mA in SPring 8 storage ring. The applied thermal cycle procedure was like followings: the chamber surface temperature was heated till 80 degrees from the room temperature (30 degrees) without ramp up rate control, then the 80 degrees was", "author_names": [ "", "Teruo Honiden", "Noritaka Kumagai", "Tatsuro Nakanishi", "Atsushi Sasagawa", "S Sasaki" ], "corpus_id": 138773404, "doc_id": "138773404", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Development of the Ceramic Chamber Integrated Pulsed Magnet Fitting for a Narrow Gap", "venue": "", "year": 2015 }, { "abstract": "The Hell Gap point, excavated from a cultural level dated by radiocarbon at 8890 B.C. (10,850+550 B.P. is described by H. M. Wormington. It represents the oldest known cultural level at Hell Gap, an extensive multicomponent quarry site occupied by paleo Indian groups over a considerable period of time. IN THE HELL GAP valley of east central Wyoming, some 13 miles north of the town of Guernsey, a series of sites or stations containing paleo Indian assemblages are being excavated by a crew of University of Wyoming students under my direction and with the support of the American Philosophical Society. At the Kimball station (SE1/4, SE1/4, SE/4, Sec. 10, T28N, R65W) an Agate Basin horizon has been found overlying a cultural zone radiocarbon dated at 8890 B.C. (10,850 550 B.P. Isotopes Inc. This early deposit contains a type of projectile point for which the name Hell Gap is proposed (Fig. 1) H. M. Wormington, who has given valuable technical aid throughout the project, describes the point type as: a lanceolate form, reminiscent of the Agate Basin type, yet different enough to be regarded as a separate point type. Of the six whole and fragmentary points recovered, three have so marked a basal constriction that they may be considered as essentially stemmed. Bases are straight or slightly convex. Cross sections range from relatively thin ovals to almost diamond shaped. Flaking was by carefully controlled percussion. Pronounced basal grinding is present along the constricted portion. Size range of whole points is from 60 to 88 mm. For purposes of comparison, plastic casts of a Hell Gap point may be obtained from the Denver Museum of Natural History. The Warrick station (NW1/4, SEY4, SE4, Sec. 10, T28N, R65W) lies within the same valley but several hundred yards southeast from the Kimball excavations. At the Warrick site there is a highly productive Agate is point, for example, B.P. (1948) B.P. (1961) if they sist in this habit. ere are already enough problems with radioc rb n e figures without adding more. In fact, s the years ss, there will be reason to reg t that m ny of the ted age figures wer not published toge her with the Basin horizon but no well defined Hell Gap level. In a lower cultural horizon which appears to correlate with the Hell Gap stratum at the Kimball site was found a fragmentary point which has the general outline, thin cross section, and fine flaking of a Folsom point, but whic is unfluted. The radiocarbon date of 8820 B.C. (10,780 B.P.+375) for Folsom at the Lindenmeier site (Haynes and Agogino 1960) and the Hell Gap date are essentially compatible. Geological investigations of the Hell Gap area are being conducted by Vance Haynes. Preliminary work reveals that a loess sequence containing paleosols and disc nformities overlies gravels and silts that presumably rest on bedrock. A marked erosional unconformity and paleosol within the loess sequence is interpreted as representing Two Creeks time. This is supported by the radiocarbon date of 8890 B.C. from the Hell Gap occupation level which rests on the unconformity. Other pertinent Pleistocene and Recent climatic events are believed to be represented in the stratigraphy and geomorphology of the Hell Gap area. Points of the Hell Gap type, although not previously defined, have been noted as occurring as isolated finds in Canada and various parts of the United States. They are a minor component in the Russell A. Johnston collection, gathered near Cereal in southern Alberta from blowouts which also yielded Agate Basin points, artifacts of the Cody Complex, and Alberta points. The latter resemble Scottsbluff, but are wider and longer with more pronounced stems and rounded bases. Few Hell Gap points have been recorded from Montana and Idaho, but such points are relatively common in eastern sections of Wyoming and Colorado and can be occasionally found in the central and western parts of these states as well. Hell Gap points were noted in the surface collections of Merrill Potter, Earl White, and James Duguid of Wyoming, and among the artifacts collected by Bert Mountain and the late Perry Andersen of Colorado. In New Mexico, points typologically similar to Hell Gap are referred to as J points by local collectors. Jpoints differ from Hell Gap points by having greater body to stem width (although there is considerable overlap) and a tendency to unground lateral edges. Fred Wendorf and Tully H. Thomas (1951: 108 9) report finding a point of Hell Gap type in an erosional blowout that also produced Folsom material near Concho, Arizona (Wendorf and Thomas 1951, Fig. 47) Since Folsom Hell Gap material can only be found in this region in blowouts that cut into pre altithermal strata, Wendorf (Wendorf and Thomas 1951: 109) suggests that this paleo Indian occupation probably preceded the erosional cycle which is attributed to the post glacial optimum. This Altithermal erosional cycle is believed to have commenced about 5000 B.C. giving a minimum date for Folsom Hell Gap material in the region. Lake Mohave points from southern California are generally cruder but are reminiscent in outline of Hell Gap material. Lake Mohave points are found in mixed izo but no wel defined Hell Gap level. In a l ral horizon which ap ears to cor elate with ll a stratu at the Kimball site was found a a point which has the general outline, thin io and fine flaking of a Folsom point, but 558 VOL. 26, No. 4, 1961 This content downloaded from 207.46.13.52 on Mon, 24 Oct 2016 04:10:54 UTC All use subject to http:/about.jstor.org/terms", "author_names": [ "George A Agogino" ], "corpus_id": 163713570, "doc_id": "163713570", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "A New Point Type from Hell Gap Valley, Eastern Wyoming", "venue": "", "year": 1961 }, { "abstract": "We have been improving the Main Ring (MR) for the beam power of 750 kW which is first goal of MR in J PARC. The repetition period of the Fast eXtraction (FX) must be shorten to 1.3 sec from the current period of 2.48 sec for the increasing the beam power. We have been upgrading injection and FX magnets. We have exchanged an injection septum magnet which were located at the injection line from RCS to MR and its power supply in summer 2016. In this paper, we describe the final results of the measurement of the gap field, leakage field. We also describe the result the beam study for evaluation of the effect by the leakage field of the new injection septum magnet. NEW INJECTION SEPTUM MAGNET SYSTEM Figure 1: The schematic of the Injection Magnets group in MR in J PARC. The beam power in FX operation of J PARC MR have achieved 470 kW in Mar. 2017. For upgrading to 750 kW, which is our first goal of the beam power, we need to increase beam intensity and extraction repetition. The present repetition period is 2.48 sec and our first goal is 1.3 sec. We have been upgrading the Injection and FX magnet systems for the high power beam. The schematic chart of the present Injection magnets in the MR are shown in Fig. 1. These magnets inject the 3 GeV proton beam from the RCS1 into the MR in 120 msec. There is an injection septum magnet, which the field of the previous one was 1.44 Tesla and integrated field (BL) was 2.81 T*m and the bending angle was 220 mrad for beam operation. We are calling it High Field Septum Magnet(HF Inj Septum) The replacement of the HF Inj Septum is one of the project of the upgrading to high power beam. We have finished the replacement of the HF Inj Septum into the MR in summer 2016. The detail of the motivation and its specification were described in [1] The tatsunobu.tshibata@j parc.jp 1 Rapid Cycling Synchrotron final figure of the HF Inj Septum after installation of the new injection and circulating duct is shown in Fig. 2 2. Figure 2: The photogtaphs of the new HF Inj Septum which were assembled in early of Jlu 2016. FINAL EVALUATION OF THE NEW HF INJ SEPTUM Measurement of Gap Field Figure 3: The original and corrected pattern(Left) and results of BL with the corrected patterns(Right) The final measurement of the gap field and leakage field along the circulating line was conducted in end of July 2016. We used the search coils for measurement of gap field, and used hole sensor for measurement of leakage field. The BL were calculated by using waveforms of magnetic field which were measured along the tracks. One of the important is flatness of the BL at flat top of the current pattern. The orignal current pattern waveform had perfect flatness at the flat top, but the flatness of its BL was not perfect due to the induced field which is generated by eddy current on the surface of the injection duct. We made the corrected current patterns for cancelling of the effect of the eddy current. The Figure 3 shows the original and corrected current pattern waveform(left) and the BL with corrected patterns of 2 We produced a new inejcton duct and circulating duct in Mar. 2016 [1] MOPIK034 Proceedings of IPAC2017, Copenhagen, Denmark ISBN 978 3 95450 182 3 576 Co py rig ht (c) 20 17 CC B Y3. 0 an d by th er es pe ct iv ea ut ho rs 04 Hadron Accelerators T12 Beam Injection/Extraction and Transport Figure 4: The Gap field(Left) and the correlation between the BL and the setting current(Right) which the current were varied from 2,300 A to 3,400 A. The vertical axis is normalized with the BL value at the end of flat top. All of flatness achieved below 5x10 5. The gapfield distribution along the track of center of beam with the corrected patterns and the correlation between the measured the BL and the setting current are shown in Fig. 4. In the left figure, the maximum magnetic field with 2,300 A and 3,400 A were 1.32 Tesla, 1.78 Tesla, respectively 3. In the right figure, the red line means a straight line and a blue line means fitting line. We could see that the correlation has good linearity below the 2,800 A, by contrast we could see that the saturation of BL above 2,800 A. The design BL with the previous magnet was 2.81 T*m. The current for the beam operation was estimated 2,590 A which corresponds with 2.81 T*m. The bending angle was estimated 221 mrad. Measurement of Leakage Field We have constructed the triple magnetic shields for reducing the leakage field along the circulating beam line. The most inner shield is the circulating duct itself of which the material is pure iron [1] and another two shields are also pure iron which are covering the circulating duct(Fig. 5(Upper) We have measured the leakage field on three tracks of which the length were about 4.5 m along the circulating duct. The mapping and the BL with 2,700 A and 3,400 A are shown in Fig. 5, where the position of 0 mm was at the edge of downstream of the magnet. The magnetic field in the figures means the average value in 120 msec time window for beam injection, and the positive direction of the field was defined as down to up. In case of 2,700 A, the maximum leakage along the circulating duct on the center of track was about 0.5 Gauss. We could see the multi pole field component by the dependence on the distance from the septum plate. We detected about 7 Gauss leakage on the center track in the upstream region from the edge of the circulating duct. The source of the large field is magnet coil at injection port which has no shield such as field clamp. These BL were calculated in the extent from 124 cm to +250 cm along each track. According to the results(Fig. 5(right) the BL in beam injection time window with 2,590 A and 3400 A 3 The maximum field of the previous one was 1.47 Tesla Figure 5: The vertical leakage field and its BL with 2590 A(Upper) and 3400 A(Lower) where the leakage field was calculated as average in beam injection time. We did not intergate the region above +250 cm, because a QM is located at this position in real beam line. were 0.1 mT*m and 0.4 mT*m, respectively. On the other hand, the BL in beam acceleration time window were about 0.2 mT*m. These BL with the new magnet are smaller than that with the previous magnet From above, we could confirm that the leakage field was enough lower than that of the previous. Consumption Power with 1 Hz Operation We summarize the results ofmeasurement of consumption power of the power supply and joule heat of the magnet coil under 1 Hz operation. The consumption power with 2,590 A and 3,400 A were 140 kW and 240 kW, respectively. The joule heat were 63 kW and 200 kW. We estimated the consumption power with 2,590 A under 2.48 sec repetition, which is present MR beam operation condition, as 56 kW, and it was about half of that with previous power supply. The consumption power with previous power supply under same condition was about 100 kW. THE BEAM OPERATION WITH THE NEW HF INJ SEPTUM After the final measurement of the magnetic field, we replaced the original HF Inj Septum and its power supply Proceedings of IPAC2017, Copenhagen, Denmark MOPIK034 04 Hadron Accelerators T12 Beam Injection/Extraction and Transport ISBN 978 3 95450 182 3 577 Co py rig ht (c) 20 17 CC B Y3. 0 an d by th er es pe ct iv ea ut ho rs with new. Figure 6 and 7 show the new magnet and the power supply which were installed in MR. Figure 6: The new HF Inj Septum which were installed in the beam line in MR in summer 2016. Figure 7: The new power supply of the HF Inj Septumwhich were installed in power supply building in MR area. The beam operation with the new HF Inj Septum was started in Oct. 2016. The latest operation current which were optimized by injection beam tuning, in Apr. 2017, is 2,598 A. The one of the most important is the potential of the leakage field to impact the circulating beam. We have evaluated the impact by monitoring the position of the circulating beam during beam study of MR in Nov. 2016. The beam position was measured with a Beam Position Monitor(BPM) which are located near the HF Inj Septum. In the beam study, we changed the time width of flat top of the pattern current for HF Inj Septum from 0.2 sec to 0.4 sec. The time variation of the beam position measured by the BPM is shown in Fig. 8. The HF Inj Septum exicited until 550 msec in the left figure. We could see that the beam position was 0.2 mm during no leakage time region. On the other hand the beam position was 0 mm during flat top of the HF Inj Septum, furthermore the beam position changed about 0.4 mm during fall time. The kick angle(BL) corresponds with the 0.4 mm shift was estimated approximately 2.5 mT*m with SAD, so the kick angle consistent with the results of the measurement of leakage field. The kick angle is not serious problem for the present beam condition, but we plan to install the additional shield for reducing the leakage as much as possible. However, we must be careful the leakage field of a QMwhich is located at the upstream of HF Inj Septum. Because about 200 Gauss leakage field from the QM also exists in same area. The rejection of the leakage field of the QM can not be permitted, because the beam condition are optimized including the leakage. So, we are making the design of the additional shield for rejecting only the leakage field from the magnet coil of HF Inj Septum. We plan to produce the additional shield by summer 2017. Figure 8: The shift of the beam position which was measured with BPM due to the leakage field of the injection septum.", "author_names": [ "Tatsunobu Shibata", "Kuanjun Fan", "Koji Ishii", "Hiroshi Matsumoto", "Noriyuki Matsumoto", "Takuya Sugimoto" ], "corpus_id": 197677773, "doc_id": "197677773", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "The New High Field Injection Septum Magnet System for Main Ring of J PARC", "venue": "", "year": 2017 }, { "abstract": "1190 Discovery Gap located at 37deg N, 16deg W is known as the terminal point of Antarctic Bottom Water spread ing with a potential temperature less than 2degC. Only warmer water has been found north of this gap. This paper presents the results of measurements of temper ature, salinity, and currents in the gap performed in October 2011. A comparison is made with the mea surements of British oceanographers [3] from 1982. Antarctic Bottom Water formed over the continen tal slope of Antarctica propagates over long distances to the north through abyssal basins of the Atlantic Ocean and abyssal channels connecting these basins [2] Starting from 2002, the Shirshov Institute of Oceanology, Russian Academy of Sciences, has been carrying out studies of Antarctic waters in the deep channels of the Atlantic, namely, the Vema Channel (31deg S) the Romanche Fracture Zone (equator) Kane Gap (9deg N) and Vema Fracture Zone (11deg N) In October 2011 during the expedition on R/V Aka demik Sergei Vavilov, a new set of investigations was performed in Discovery Gap. The ridge located in the East Azores Fracture Zone located at 37deg N is considered the terminal point for Antarctic Bottom Water spreading as the water that is defined as water with a potential temperature below 2degC [5] Water exchange between the Madeira and Iberian deep water basins occurs through Discov ery Gap located in this ridge at 16deg W (Fig. 1) The depth of both basins exceeds 5300 m. The length of Discovery Gap is approximately 150 km, and the width is 10 50 km (along the 4500 m isobath; Fig. 1) Based on the bottom topography database [4] (version V14.1) the gap has three sills with close depths from 4680 to 4711 m. Their location is shown in Fig. 1. The slope of the gap walls exceeds 1/5 [3] The first detailed studies in the region of Discovery Gap were carried out in 1982 [3] Several CTD sec tions were occupied, and six long term moorings with 10 current meters were deployed during these studies. Neutral floats were released in the bottom layer at a depth of approximately 4700 m, which were traced for 10 days. The mean water transport based on the data in [3] which gives analysis of these data, was directed to the northeast along the channel. The velocities were approximately 5 cm/s. The transport of water with tem peratures less than 2.05degC from the Madeira Basin to the Iberian Basin was estimated in the paper at 0.2 Sv. In order to save the ship time, the section in 2011 was located in the narrowest place of Discovery Gap practically on the line of one of the sections in 1982 west of the eastern sill of the gap (Fig. 1) to have the possibility of comparing the data. A survey of bottom topography was performed before the measurements in October 2011 to locate the profiling stations more carefully. Profilings at three CTD stations over a sec tion 20 km long (Fig. 1) were made using an SBE 19 profiler combined with a lowered current profiler RDI WHS (300 kHz) Figure 2 shows a section of potential temperature (2011) across Discovery Gap. In general, the section repeats the characteristic features of the section in 1982. Elevation of all isotherms by approximately 200 250 m is notable, which indicates the integral cooling of the flow. The dotted line in Fig. 2 shows for comparison the 2.02degC isotherm based on the data in [3] Over the 29 years that have passed, the minimal temperature on the section decreased by almost a hun dredth of a degree from 2.011degC in 1982 to 2.002degC in 2011. As in 1982, the cold core is displaced to the eastern slope. The vertical temperature gradient at depths of 4000 m changes to a mixed layer in the deeper layers of the gap. The salinity distribution dem onstrates a similar displacement of fresher water to the eastern slope. The data of the lowered ADCP were processed using the programming package for LADCP, version IX.7. The results of processing demonstrated low current veloci ties compared with the velocities of the barotropic tide. A correction for the tidal velocities was calculated Discovery Gap: The Terminal Point of Antarctic Bottom Water Spreading", "author_names": [ "Eugene G Morozov", "R Yu Tarakanov" ], "corpus_id": 128825739, "doc_id": "128825739", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Discovery gap: The terminal point of antarctic bottom water spreading", "venue": "Doklady Earth Sciences", "year": 2012 }, { "abstract": "We are improving the Main Ring (MR) for beam power of 750 kW which is the first goal of J PARC. The repetition period of the Fast eXtraction(FX) must be short to 1.3 sec from the current period of 2.48 sec for the improvement of the beam power. It is necessary to exchange a high field injection septum magnet which will be installed at the injection line from RCS to MR and its power supply, because the current injection septum system can not be operated with 1.3 sec repetition. Since confirmed the large leakage field around current circulating beam line of the injection magnet, we must improve the shielding structure which make low leakage field. We started the development of the new injection septum magnet and its power supply in 2013. It can operate with 1 Hz repetition and the low leakage field which its order is 10 4 of the gap field. The new Injection septum magnet and the new power supply were constructed in 2014. We had many improvement of the magnet and power supply. We will install the new injection septum magnet system in this summer. In this presentation, we will report the detail of the results of its performances. NEW INJECTION SEPTUM MAGNET SYSTEM Figure 1: The schematic of the Injection Magnets group in MR. The beam power for FX mode of J PARC MR achieved 395 kW in Feb. 2016. For 750 kW in which our first goal of the beam power, we need to increase beam intensity and extraction repetition. The present repetition period is 2.48 sec and our goal is 1.3 sec1. We are upgrading the Injection and FX magnet systems for the high power beam. The schematic chart of the present Injection magnets in the MR are shown in Fig.1. These magnets in* tatsunobu.tshibata@j parc.jp 1 We are calling it as 1 Hz operation. ject the 3 GeV proton beam from the RCS2 into the MR in 120 msec. The first injection septum magnet of which the field is 1.44 Tesla(BL=2.81 T*m) bends the proton beam 220 mrad. We are calling it as High Field Septum Magnet(HF Inj Septum) There are several reasons of necessity of a new HF InjSeptum. The main reason is the present power supply(P.S. can not operate with 1 Hz. The present P.S. outputs a pattern current of which the rise time is 0.25 sec, flat top time is 0.2 sec, and the fall time is approximately 1 sec. The source of such a long fall time is that the output inverter unit has 1 IGBT and it does not control negative voltage. The joule heat at the coil will increase by 1 Hz operation, and the size of its hollow must be larger than present size, ph4.8 mm. The second reason is the beam duct needs more large aperture for the high power beam. The aperture of the present injection duct is 150 mm(H)x80 mm(V) but it is not enough size for high power beam emittance such as 80p. The third reason that he leakage field around downstream region of the beam duct is still high for high power beam, and we need to reduce more. The present HF Inj Septum has two magnetic poles of which the length is 900 mm each other, and the leakage field exists at the opening space of them [1] The current for normal operation is 2800 A, but since the maximum current is 2900 A the present P.S. can not operate for 3.3 GeV injection which is one of the future plan. The important requirements for the new are 1 Hz operation, large aperture, low leakage field, and high current for 3.3 GeV injection. We developed a new one which satisfies all of above requirements in 2014. Fig.2 shows the new magnet and components of the P.S. The input AC400 V is rectified to DC480 V by IGBT converter units and charges are stored in the capacitor units. The output inverter units have 4 IGBT units and it can output negative voltage to control its fall time. The rise, flat top and fall time with the new P.S. are all 0.2 sec. The digital feedback system is used for high stability of its output current. To reduce its consumption power, the magnetic energy in the inductance of the magnet returns to the capacitors. The new P.S. bases on new power supply for the main magnets of J PARC MR. We also designed a new magnet for resolving above problems. The new HF Inj Septum is \"sector\" type septum [2] We installed an end field clamp for covering the edge of coils at the exit of the injection duct for reducing the leakage field. The field clamp consists with laminated Si steel sheets which are covered with SUS plates. The new aperture of the injection duct is 180 mm(H)x80 mm(V) We se2 Rapid Cycling Synchrotron Proceedings of IPAC2016, Busan, Korea TUPMR039 04 Hadron Accelerators T12 Beam Injection/Extraction and Transport ISBN 978 3 95450 147 2 1337 C op yr ig ht (c) 20 16 C C B Y3. 0 an d by th e re sp ec tiv e au th or s lected new hollow conductors of which the hollow size are ph6.0 mm. We will install the new HF Inj Septum into the MR in summer 2016. Figure 2: The diagram of the new power supply(Upper) The photograph of the new magnet(Lower) EVALUATION OF THE NEW HF INJ SEPTUM The gap field must be stable and its BL must be flat at flattop. The required reproducibility of the gap field and flatness of the BL are less than 10 4. The leakage field must be less than 1 Gauss which is 10 4 of the gap field. To evaluate the new HF Inj Septum, we measured the gap field and leakage field. We produced some search coils to measure the gap field. The search coil consists of 1,000 turn coils which winds on a ph4 cm diameter non magnetic bobbin. The output voltage of the search coil is proportional to time difference of magnetic field. We also produced X Y Z scanner with three electric sliders for mapping of gap field. We used a gauss meter( model 8030 of F.W.BELL which uses hole sensors to measure the leakage field. The waveforms of field were recorded with a 16 bit ADC board model SL1000 of YOKOGAWA DENKI Its sampling rate was 5 kSamples/sec, and the recorded time window was 1 sec. Measurement of Gap Field and Flatness of BL We measured the BL with 2800 A and 3400 A3 output. The results of the mapping of gap field and its BL are shown in Fig.3, where the 0 mm position was defined as face of upward flange of the injection duct. We confirmed that the measured BL with 2800 A was large than 2.81 T*m, it was enough large for normal MR operation. The flatness, which we defined as the difference of BL between 120 msec which is timing difference of first and last beam bunches injection, were 2.5x10 4 and 4.2x10 4 with 2800 A and 3400 A, respectively. Both of them were large than 10 4 and they did not satisfy our requirements. The main source of problem was effect of magnetic field by eddy current which 3 The current at flat top. Figure 3: The results of the gap field(Left) and BL(Right) were induced at the surface of the injection duct. We made the corrected current patterns for reduction of the effect of eddy current. Fig.4 shows the corrected current pattern for 3400 A and the results of BL with corrected patterns for 2700 A, 2800 A, 3100 A and 3400 A. The vertical axis was normalized with maximum value of BL in flat top. All of results of the flatness were 10 5. Figure 4: The normal and corrected pattern(Left) and results of BL with the corrected patterns(Right) Measurement of Leakage Field We installed some additional inner SUY shields of which their thickness were 5 mm to reduce leakage field in the circulating region. We measured the leakage field at the center of the duct along beam direction. Fig.5 shows the mapping and its BL of leakage field with 2800 A and 3400 A, where the 0 cm position was the edge of magnetic pole. The average means averaged value in 120 msec at flat top and the peak means peak value in beam acceleration time during TUPMR039 Proceedings of IPAC2016, Busan, Korea ISBN 978 3 95450 147 2 1338 C op yr ig ht (c) 20 16 C C B Y3. 0 an d by th e re sp ec tiv e au th or s 04 Hadron Accelerators T12 Beam Injection/Extraction and Transport fall time. The 1.5 Gauss existed at 1.2 m far from the exit of the circulating duct with 3400 A. The leakage field increased at the outside of circulating duct, because of no shield around there. We confirmed that the leakage field with 2800 A was less than 1 Gauss in the circulating duct and it was enough lower than our requirement. The BL with 2800 A was ~1 Gauss*m and it is also less than that of present magnet. The BL with 3400 A in beam injection time was ~4 Gauss*m, it was same as present. Figure 5: The leakage field with 2800 A and 3400 A(Right upper) where(1)Average in injection time with 2800 A (2)Average with 3400 A (3)Peak in Acceleration time with 2800 A (4)Peak with 3400 The BL with 2700 A,2800 A,3100 A,3400 A(Right Lower) The serious vacuum leak at the welding position which were connected the flange and injection duct was happened in Aug. 2015. The main source of the problem could be presumed the structural defect of the edge of the injection duct. We had to redesign a new injection duct to solve its defect. We also decided to redesign a new circulating duct of which the material was SUY. Because the inner SUY shield was very effective, and we wanted to unify the inner shield and circulating duct. The production of the new injection and circulating ducts were completed in Mar. 2016. We have plan to measure the leakage field and BL again with the new ducts. Reproducibility of Current and Gap Field We will describe the reproducibility of the gap field and current. We used output signal of a DCCT, which is used for feedback system, in the output unit of P.S. to measure the current. The output signal of DCCT were converted to current difference by 20 bit AD and DA converters and feedback controller. The current difference means the difference between setting and measurement current. We kept the operation several hours with 0.5 Hz repetition for monitoring its time variation. Only gap field had obvious variation because of thermal expansion of search coil, and we used events only after stabilization for evaluation of reproducibility. The definition of reproducibility is ratio of the r.m.s. a", "author_names": [ "Tatsunobu Shibata", "Kuanjun Fan", "Koji Ishii", "Hiroshi Matsumoto", "Noriyuki Matsumoto", "Takuya Sugimoto" ], "corpus_id": 125118674, "doc_id": "125118674", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "The Development of a New High Field Injection Septum Magnet System for Main Ring of J Parc", "venue": "", "year": 2016 }, { "abstract": "The liver is the metabolic center of the mammalian body and serves as a filter for the blood. The basic architecture of the liver is illustrated in figure 1 in which more than 85% of the liver mass is composed of hepatocytes and the remaining 15% of the cellular mass is composed of Kupffer cells (KCs) stellate cells (HSCs) and sinusoidal endothelial cells (SECs) SECs form the blood vessel walls within the liver and contain specialized morphology called fenestrae within in the cytoplasm. Fenestration of the cytoplasm is the appearance of holes ~100 mm) within the cells so that the SECs act as a sieve in which most chylomicrons, chylomicron remnants and macromolecules, but not cells, pass through to the hepatocytes and HSCs 1 (Fig. 1) Due to the lack of a basement membrane, the gap between the SECs and hepatocytes form the Space of Disse. HSCs occupy this space and play a prominent role in regulation and response to injury, storage of retinoic acid and immunoregulation of the liver 2. SECs are among the most endocytically active cells of the body displaying an array of scavenger receptors on their cell surface 3. These include SR A, Stabilin 1 and Stabilin 2. Generally, small colloidal particles less than 230 nm and macromolecules in buffer phase are taken up by SECs, whereas, large particles and cellular debris is endocytosed (phagocytosed) by KCs 4. Thus, the bulk clearance of extracellular material such as the glycosaminoglycans from blood is largely dependent on the health and endocytic functions of SECs 5,6. For example, an increase in blood hyaluronan levels is indicative of liver disease ranging from mild to more severe forms 7. With the exception of one report 8, there are no immortalized SEC cell lines in existence. Even this immortalized cell line is de differentiated in that it does not express scavenger receptors that are present on primary SECs (our data, not shown) All cell biological studies must be performed on primary cells obtained freshly from the animal. Unfortunately, SECs dedifferentiate under standard culture conditions and must be used within 1 or 2 days upon isolation from the animal. Differentiation of SECs is marked by the expression of Stabilin 2 or HARE receptor 9 CD31, and the presence of cytoplasmic fenestration 1. Differentiation of SECs can be extended by the addition of VEGF in culture media or by culturing cells in hepatocyte conditioned medium 10,11. In this report, we will demonstrate the endocytic activity of SECs in the intact organ using radio labeled heparin for hyaluronan for the SEC specific Stabilin 2 receptor. We will then purify hepatocytes and SECs from the perfused liver to measure endocytosis.", "author_names": [ "Sandhya Lakshmi Gopalakrishnan", "Edward N Harris" ], "corpus_id": 35989033, "doc_id": "35989033", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "In vivo Liver Endocytosis Followed by Purification of Liver Cells by Liver Perfusion", "venue": "Journal of visualized experiments JoVE", "year": 2011 }, { "abstract": "FAIMS MS has been used for the analysis of non covalent complexes formed by 3 MX. The singly charged (3 MX) n (n 4 12) complexes show maximum FAIMS transmission at different CF values, with the optimum CF decreasing as the size of the cluster increases (Fig. 4) 3 Methylxanthine was prepared as a 0.5 mM solution in 60:40 methanol:water with 1 mM ammonium acetate, or with 1 mM sodium hydroxide, to promote the formation of 3 MX clusters with Na and to enable the detection of higher ordered clustered 3 MX structures. 3 MX solutions were analysed by FAIMS using an Agilent 6230 TOF MS (Agilent Technologies) with a Jet Stream ESI source, combined with a prototype miniaturised chip based FAIMS device (Owlstone Ltd. Cambridge) located in front of the mass spectrometer inlet capillary (Fig. 2) The FAIMS device consists of multiple planar electrode channels each with a 100 um gap and an electrode length of 700 um. The TOF MS experimental conditions in positive ion mode were: drying gas: 8 L/min at 150 degC; sheath gas: 10 L/min at 200 degC; nebuliser gas: 30 psig; capillary voltage: 3.5 kV; nozzle voltage: 2 kV; fragmentor voltage: 150 250 V; and a sample flow rate of 10 uL/min using a syringe pump. The optimum FAIMS conditions for the selective transmission of the different 3 MX clusters, singly, doubly and multiply charged species, were determined by conducting a compensation field (CF) sweep from 2 to 5 Td at a rate of 0.5 Td/sec, for dispersion fields (DF) in the range 194 to 323 Td. Conclusions Hyphenation of FAIMS MS and IM MS has been used for the analysis of 3 MX complexes. This preliminary study into the structural analysis of 3 MX complexes shows a complexity of non covalently clustered structures. FAIMS selection has been used for the separation of overlapping charge states of 3 MX complexes. Increased S:N ratio is observed for higher order 3 MX complexes using FAIMS MS. 3 MX singly charged complexes formed in the presence of sodium show different CF values", "author_names": [ "Kayleigh L Arthur", "James C Reynolds", "Colin S Creaser" ], "corpus_id": 96666522, "doc_id": "96666522", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An investigation of 3 methylxanthine supramolecular complexes using field asymmetric waveform and drift tube ion mobility spectrometry combined with mass spectrometry", "venue": "", "year": 2013 }, { "abstract": "The luminescence of ptype GaP(Zn,O) a semiconducting mater ial for light emit t ing diodes, is controlled by the transit ions of the excited free electrons and by those of the electrons bound to the luminescent neares t neighbor (ZncaOp) complexes. The results of the determinat ion of the in terna l quan tum efficiency ~l) on a large number of samples, prepared by solution growth and by liquid phase epitaxy and covering a zinc concentrat ion range of 1027 5 9 10 is cm lead to the conclusion that an Auger effect acting on the bound electrons is the dominant cause of the reduction of the in ternal efficiency of the samples with a free hole concentrat ion (p) above 4 9 1017 cm where also the t rapping by \"killers\" becomes negligible. The Auger constant was derived, being 3 9 10 11 cm 3 sec 1. Below this concentrat ion the thermalizat ion of the electrons bound to the complexes is the more impor tant effect enhancing the otherwise relat ively small action of the killers. The best value for is ~40% at p ~5 9 1017 cm Decay time measurements, using pulsed and s ine wave modulated excitation, provide insight in the effect of screening by free holes on the radiative and Auger transit ions by using in the interpretat ion of the data the quant i ty (m/T) which is proportional to the effective radiat ive recombinat ion rate including the effect of screening ment ioned) Both radiative and Auger t ransi t ion probabilit ies are reduced by a common screening factor as low as 0.2. Electron diffusion length measurements on the epitaxial samples show a strong decrease of the minor i ty carrier l ifetime with increasing zinc concentrat ion which is ascribed main ly to the t rapping by the (ZnO) complexes whose concentrat ion increases with the zinc dolce. This study also provides information on the oxygen incorporation dur ing the crystal growth. This incorporation probably takes place at thermal equi l ibr ium between the oxygen source and the solid GaP. [O] increases with [Zn] reaching ~10 is cm 3 at [Zn] 5 10 is cm Semiconductor diodes that emit visible l ight are of increasing importance for certain applications, i.e. for indication and for display of symbols. The luminescence efficiency of such diodes is general ly much below 100% Various causes exist for this circumstance part of which are peculiar to the semiconductor material used and to the devices made from them. These causes are still a mat ter oi conjecture. In this respect the subject of this paper, ptype gal l ium phosphide doped with zinc and oxygen, is no exception. Par t ly these causes arise from the properties of the l ight emit t ing layer, i.e. ptype GaP(Zn, O) Another cause, general ly of minor importance for this type of material, is the l imited efficiency of inject ion of electrons into this layer. A study of dopant dependent recombinat ion in ptype GaP(Zn, O) is useful to elucidate the relevant properties of this layer with respect to both bulk efficiency and inject ion efficiency. With regard to the bulk efficiency results have been published by Dishman, DiDomenico, and Caruso (1) and Jayson, Bhargava, and Dixon (2) They used the dopant dependence of two observables, quan tum efficiency and decay time. In Ref. (1) it was tr ied to determine the in terna l quan tum efficiency, a difficult exper imental problem, while Ref. (2) emphasized the decay measurements. In view of the large number of model parameters a priori statements on some of these parameters were used, par t ly based on a theoretical s tudy by Sinha and DiDomenico (3) References (1) and (2) essentially used a recombinat ion model for which Fig. 1 shows a simplified level and t ransi t ion diagram. It is seen that the losses arise from two groups of nonradia t ive transit ions labeled 'nk and rn which act on the free and bound electrons, respectively, and which paral lel the transit ions rnt and rr that", "author_names": [ "J A W van der Does de Bye" ], "corpus_id": 96737289, "doc_id": "96737289", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Dependence of Recombination in p Type GaP Zn O on Dopant Concentrations", "venue": "", "year": 1976 }, { "abstract": "We report point contact spectroscopy measurements on YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta] thin films and textured bulk ceramics. The I(V) curves measured along the copper oxygen ab plane direction are characteristic of the Andreev reflection phenomenon, with a sharp break at the gap edge. This allows a rather precise determination of the (in plane) gap, [Delta] 20 meV. Subgap structure suggests the existence of a smaller gap for some orientations in the ab plane, of the order of 12 meV. The ratio of the zero bias conductance to the normal state one, in the ab direction measurements, enabled us to set a lower bound to the Fermi velocity in YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta] in this direction: v[sub F][ge]7 x 10[sup 7] cm/sec. The value of v[sub F] has a crucial importance in the determination of the theoretical explanation for superconductivity in the high temperature superconductors. For out of plane measurements, only a weak zero bias anomaly is observed at energies up to 5 meV. 18 refs. 4 figs.", "author_names": [ "Nir Hass", "Guy Deutscher", "Danielle Ilzycer", "Gilbert Desgardin", "Isabelle Monot", "Meir Weger" ], "corpus_id": 117838674, "doc_id": "117838674", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Sharp gap edge and determination of the Fermi velocity in Y[sub 1]Ba[sub 2]Cu[sub 3]O[sub 7[minus][delta] by point contact spectroscopy", "venue": "", "year": 1992 } ]

[ { "abstract": "", "author_names": [ "Qixin Guo Katsuhiko Saito Tooru Tanaka", "Mitsuhiro Nishio" ], "corpus_id": 136056093, "doc_id": "136056093", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Crystal growth of gallium oxide based wide bandgap semiconductors", "venue": "", "year": 2016 }, { "abstract": "Gallium oxide is not a novel material, but has been overlooked in favor of semiconductors like gallium nitride and silicon carbide. It is a typical ultra wide bandgap material and has attractive material properties represented by its extremely large bandgap of 4.85 eV. Recent revolution in its bulk single crystal growth methods has inspired scientist to research more on this material. Though the research on the material has picked up, there is still a lot of ground to cover to catch up to standard commercialized semiconductors. TCAD's have inspired their own line of research based on the understanding of device physics, and most TCADs are tailored to standard semiconductors. In this thesis we address one such device physics required to determine the breakdown voltage of gallium oxide devices, the physics of impact ionization. We use known physical properties of gallium oxide in standard models to obtain an estimate of the ionization coefficients. We also determine certain properties, essential for the estimation of the coefficients, based on approximation models. The estimates are compared with GaN and SiC and is found to be higher in gallium oxide as expected.", "author_names": [ "Giftsondass Irudayadass" ], "corpus_id": 216877145, "doc_id": "216877145", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Estimation of Ionization Coefficients of Gallium Oxide for the Purpose of TCAD Simulation", "venue": "", "year": 2018 }, { "abstract": "Zinc oxide (ZnO) and gallium nitride (GaN) are wide bandgap semiconductors with a wide array of applications in optoelectronic and electronics. The lack of low cost, low defect ZnO and GaN substrates has slowed development and hampered performance of devices based on these two materials. Their anisotropic crystal structure allows the polar solvents, water and ammonia, to dissolve and crystallize ZnO and GaN at high pressure. Applying the techniques used for hydrothermal production of industrial single crystal quartz to ZnO and GaN opens a pathway for the inexpensive growth of relatively larger crystals that can be processed into semiconductor wafers. This chapter will focus on the specifics of the hydrothermal growth of ZnO and the ammonothermal growth of GaN, emphasizing requirements for industrial scale growth of large crystals. Phase stability and solubility of hydrothermal ZnO and ammonothermal GaN is covered. Modeling of thermal and fluid flow gradients is discussed and simulations of thermal and temperature profiles in research grade pressure systems are shown. Growth kinetics for ZnO and GaN respectively are reviewed with special interest in the effects of crystalline anisotropy on thermodynamics and kinetics. Finally, the incorporation of dopants and impurities in ZnO and GaN and how their incorporation modifies electrical and optical properties are discussed.", "author_names": [ "Michael J Callahan", "Qi-sheng Chen" ], "corpus_id": 91998362, "doc_id": "91998362", "n_citations": 6, "n_key_citations": 2, "score": 0, "title": "Hydrothermal and Ammonothermal Growth of ZnO and GaN", "venue": "", "year": 2010 }, { "abstract": "Historically, the exploration of III V compound semiconductors has begun with small bandgap materials and proceeded to large bandgap ones in recent years, that is, from GaAs based compounds to GaN based ones. We consider that gallium oxide (Ga2O3) is no exception in following this history and is poised to become the next mainstream of compound semiconductor research due to its attractive material properties based on an extremely large bandgap of about 4.5 eV [1] This bandgap energy is not only much larger than those of representative wide bandgap semiconductors such as GaN and SiC but also unique among single crystal semiconductors. Furthermore, Ga2O3 has another important advantage for commercialization over the other wide bandgap materials in that large size, high quality bulk single crystals can be synthesized by melt growth methods, thus allowing native substrates to be produced at a relatively low cost [2] Recently, these two features have drawn much attention to Ga2O3, resulting in a rapid expansion of the Ga2O3 community.", "author_names": [ "Masataka Higashiwaki", "Man Hoi Wong", "Takafumi Kamimura", "Yoshiaki Nakata", "Chia-Hung Lin", "R Lingaparthi", "Akinori Takeyama", "Takahiro Makino", "Takeshi Ohshima", "Naoki Hatta", "Kuniaki Yagi", "Ken Goto", "Kohei Sasaki", "Shinya Watanabe", "Akito Kuramata", "Shigenobu Yamakoshi", "Keita Konishi", "Hisashi Murakami", "Yoshinao Kumagai" ], "corpus_id": 52129023, "doc_id": "52129023", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Recent Advances in Ga2O3 MOSFET Technologies", "venue": "2018 76th Device Research Conference (DRC)", "year": 2018 }, { "abstract": "Solar blind photodetectors are of great interest to a wide range of industrial, civil, environmental, and biological applications. As one of the emerging ultrawide bandgap semiconductors, gallium oxide (Ga2O3) exhibits unique advantages over other wide bandgap semiconductors, especially in developing high performance solar blind photodetectors. This paper comprehensively reviews the latest progresses of solar blind photodetectors based on Ga2O3 materials in various forms of bulk single crystal, epitaxial films, nanostructures, and their ternary alloys. The basic working principles of photodetectors and the fundamental properties and synthesis of Ga2O3, as well as device processing developments, have been briefly summarized. A special focus is to address the physical mechanism for commonly observed huge photoconductive gains. Benefitting from the rapid development in material epitaxy and device processes, Ga2O3 based solar blind detectors represent to date one of the most prospective solutions for UV detection technology towards versatile applications.", "author_names": [ "Xuanhu Chen", "Fangfang Ren", "Shulin Gu", "Jiandong Ye" ], "corpus_id": 139759197, "doc_id": "139759197", "n_citations": 106, "n_key_citations": 2, "score": 0, "title": "Review of gallium oxide based solar blind ultraviolet photodetectors", "venue": "Photonics Research", "year": 2019 }, { "abstract": "Beta gallium oxide (Ga2O3) has received much attention recently as a viable candidate for the nextgeneration material for power electronics and photonic applications, with its unique advantages, such as the wide bandgap 4.9 eV) high breakdown voltage, and optical transparency up to UV range. Recent advances in high quality Ga2O3 thin film growth, such as using molecular beam epitaxy or chemical vapor deposition, combined with the material's availability as inexpensive bulk substrates have opened new exciting opportunities for the fabrication of novel Ga2O3 devices. Despite the advances, many of the fundamental properties of Ga2O3 are yet to be understood clearly. As in many other oxide based transparent semiconductors, point defects and their complexes can dictate the properties of Ga2O3. Various spectroscopic methods as well as theoretical calculations have provided useful insights on the nature of the point defects and complexes in Ga2O3. Regardless, what has been missing in the field is the detailed information on the atomic scale structure of the defects and complexes in Ga2O3. Such information is crucial to determine how the atomic scale defects relate to many of the unanswered questions regarding the unique properties of Ga2O3, including how point defects and impurity atoms influence the formation of trap states, how the dopant atoms are compensated, and what is the exact origin of the difficulty in doping of Ga2O3 (especially p type)", "author_names": [ "Jared M Johnson", "Hsien-Lien Huang", "Jinwoo Hwang" ], "corpus_id": 225391199, "doc_id": "225391199", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Point Defects and Complexes in Gallium Oxide Materials and Devices", "venue": "Microscopy and Microanalysis", "year": 2020 }, { "abstract": "As a promising ultra wide bandgap semiconductor, gallium oxide (Ga2O3) has attracted increasing attention in recent years. The high theoretical breakdown electrical field (8 MV/cm) ultra wide bandgap 4.8 eV) and large Baliga's figure of merit (BFOM) of Ga2O3 make it a potential candidate material for next generation high power electronics, including diode and field effect transistor (FET) In this paper, we introduce the basic physical properties of Ga2O3 single crystal, and review the recent research process of Ga2O3 based field effect transistors. Furthermore, various structures of FETs have been summarized and compared, and the potential of Ga2O3 is preliminary revealed. Finally, the prospect of the Ga2O3 based FET for power electronics application is analyzed.", "author_names": [ "Hang Dong", "Huiwen Xue", "Qiming He", "Yuan Qin", "Guangzhong Jian", "Shibing Long", "Ming Liu" ], "corpus_id": 116479224, "doc_id": "116479224", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Progress of power field effect transistor based on ultra wide bandgap Ga2O3 semiconductor material", "venue": "", "year": 2019 }, { "abstract": "Abstract In the course of development of transparent semiconducting oxides (TSOs) we compare the growth and basic physical properties bulk single crystals of ultra wide bandgap (UWBG) TSOs, namely b Ga2O3 and Ga based spinels MgGa2O4, ZnGa2O4, and Zn1 xMgxGa2O4. High melting points of the materials of about 1800 1930 degC and their thermal instability, including incongruent decomposition of Ga based spinels, require additional tools to obtain large crystal volume of high structural quality that can be used for electronic and optoelectronic devices. Bulk b Ga2O3 single crystals were grown by the Czochralski method with a diameter up to 2 inch, while the Ga based spinel single crystals either by the Czochralski, Kyropoulos like, or vertical gradient freeze Bridgman methods with a volume of several to over a dozen cm3. The UWBG TSOs discussed here have optical bandgaps of about 4.6 5 eV and great transparency in the UV visible spectrum. The materials can be obtained as electrical insulators, n type semiconductors, or n type degenerate semiconductors. The free electron concentration (ne) of bulk b Ga2O3 crystals can be tuned within three orders of magnitude 1016 1019 cm 3 with a maximum Hall electron mobility (m) of 160 cm2V 1s 1, that gradually decreases with ne. In the case of the bulk Ga based spinel crystals with no intentional doping, the maximum of ne and m increase with decreasing the Mg content in the compound and reach values of about 1020 cm 3 and about 100 cm2V 1s 1 (at ne 1019 cm 3) respectively, for pure ZnGa2O4.", "author_names": [ "Zbigniew Galazka", "Steffen Ganschow", "Klaus Irmscher", "Detlef Klimm", "Martin Albrecht", "Robert Schewski", "Mike Pietsch", "T Schulz", "Andrea Dittmar", "Albert Kwasniewski", "Raimund Grueneberg", "Saud Bin Anooz", "Andreas Popp", "Uta Juda", "Isabelle M Hanke", "Thomas Schroeder", "Matthias Bickermann" ], "corpus_id": 230553941, "doc_id": "230553941", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Bulk single crystals of b Ga2O3 and Ga based spinels as ultra wide bandgap transparent semiconducting oxides", "venue": "", "year": 2021 }, { "abstract": "Gallium oxide (Ga2O3) possesses excellent material properties especially for power device applications. It is also attractive from an industrial viewpoint since large size, high quality wafers can be manufactured by using simple methods. These two features have drawn much attention to Ga2O3 as a new wide bandgap semiconductor following SiC and GaN. In this report, we describe the recent progress in development on fundamental technologies for Ga2O3 devices, covering wafer production from melt grown bulk single crystals, homoepitaxial thin film growth by halide vapor phase epitaxy, as well as device processing and characterization of metal oxide semiconductor field effect transistors and Schottky barrier diodes.", "author_names": [ "Masataka Higashiwaki", "Kohei Sasaki", "Man Hoi Wong", "Takafumi Kamimura", "Ken Goto", "Kazushiro Nomura", "Quang Tu Thieu", "Rie Togashi", "Hisashi Murakami", "Yoshinao Kumagai", "Bo Monemar", "Akinori Koukitu", "Akito Kuramata", "Takekazu Masui", "Shigenobu Yamakoshi" ], "corpus_id": 21638568, "doc_id": "21638568", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Current Status of Gallium Oxide Based Power Device Technology", "venue": "2015 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS)", "year": 2015 }, { "abstract": "This article lists the development history and application prospect of the third generation of semiconductor material wide bandgap zinc oxide single crystal,and summarizes the structural performance,application direction and preparation technique of ZnO.The article also introduces the distinct advantages of wide bandgap zinc oxide single crystal compared to gallium nitride which are as follow:more powerful exciton binding energy(60 mev),lower lasing threshold,very likely to achieve ultraviolet laser of high efficiency and low threshold under indoor temperature.Compared to the very successful gallium nitride,the cost of the raw material for ZnO is extremely low and it is environmental friendly and easy for synthesis.For the moment,the difficult and hot issues of the research on ZnO semiconductor material focus on the research and development of p type doping materials and devices.Excellent physical properties of zinc oxide have made it a new generation of mainstream broadband gap semiconductor materials.Growth of zinc oxide single crystal of large size and high crystallization quality has a great significance for both of basic research and practical application.The method and techical advantage of hydrothermal synthesis of wide bandgap zinc oxide single crystal have been specially introduced in this article which demonstrates our latest research development of hydrothermal synthesis of wide bandgap zinc oxide single crystal.", "author_names": [ "Wang Jin-lian" ], "corpus_id": 138659936, "doc_id": "138659936", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research Progress on Hydrothermal Growth of Wide Bandgap ZnO Single Crystal", "venue": "", "year": 2015 } ]

[ { "abstract": "Point defects and impurities strongly affect the physical properties of materials and have a decisive impact on their performance in applications. First principles calculations have emerged as a powerful approach that complements experiments and can serve as a predictive tool in the identification and characterization of defects. The theoretical modeling of point defects in crystalline materials by means of electronic structure calculations, with an emphasis on approaches based on density functional theory (DFT) is reviewed. A general thermodynamic formalism is laid down to investigate the physical properties of point defects independent of the materials class (semiconductors, insulators, and metals) indicating how the relevant thermodynamic quantities, such as formation energy, entropy, and excess volume, can be obtained from electronic structure calculations. Practical aspects such as the supercell approach and efficient strategies to extrapolate to the isolated defect or dilute limit are discussed. Recent advances in tractable approximations to the exchange correlation functional \\mathrm{DFT}+U$ hybrid functionals) and approaches beyond DFT are highlighted. These advances have largely removed the long standing uncertainty of defect formation energies in semiconductors and insulators due to the failure of standard DFT to reproduce band gaps. Two case studies illustrate how such calculations provide new insight into the physics and role of point defects in real materials.", "author_names": [ "Christoph Freysoldt", "Blazej Grabowski", "Tilmann Hickel", "Jorg Neugebauer", "Georg Kresse", "Anderson Janotti", "Chris G van de Walle" ], "corpus_id": 120925498, "doc_id": "120925498", "n_citations": 1088, "n_key_citations": 12, "score": 1, "title": "First principles calculations for point defects in solids", "venue": "", "year": 2014 }, { "abstract": "A first principles calculation for uranium dioxide (UO2) in an antiferromagnetic structure with four types of point defects, uranium vacancy, oxygen vacancy, uranium interstitial, and oxygen interstitial, has been performed by the projector augmented wave method with generalized gradient approximation combined with the Hubbard U correction. Defect formation energies are estimated under lattice relaxation for supercells containing 1, 2, and 8 unit cells of UO2. The electronic structure, the atomic displacement and the stability of defected systems are obtained, and the effects of cell sizes on these properties are discussed. The results form a self consistent dataset of formation energies and atomic distance variations of various point defects in UO2 with relatively high precision. We show that a supercell with 8 UO2 unit cells or larger is necessary to investigate the defect behavior with reliable precision, since point defects have a wide ranging effect, not only on the first nearest neighbor atoms of the defect, but on the second neighbors and on more distant atoms. [doi:10.2320/matertrans.47.2651]", "author_names": [ "Misako Iwasawa", "Ying Chen", "Yasunori Kaneta", "Toshiharu Ohnuma", "Hua Y Geng", "Motoyasu Kinoshita" ], "corpus_id": 97750286, "doc_id": "97750286", "n_citations": 81, "n_key_citations": 2, "score": 0, "title": "First Principles Calculation of Point Defects in Uranium Dioxide", "venue": "", "year": 2006 }, { "abstract": "Uranium (U) exhibits a high temperature body centered cubic (bcc) allotrope that is often stabilized by alloying with transition metals such as Zr, Mo, and Nb for technological applications. One such application involves U Zr as nuclear fuel, where radiation damage and diffusion (processes heavily dependent on point defects) are of vital importance. Several systems of U are examined within a density functional theory framework utilizing projector augmented wave pseudopotentials. Two separate generalized gradient approximations of the exchange correlation are used to calculate defect properties and are compared. The bulk modulus, the lattice constant, and the Birch Murnaghan equation of state for the defect free bcc uranium allotrope are calculated. Defect parameters calculated include energies of formation of vacancies in the a and g allotropes, as well as self interstitials, Zr interstitials, and Zr substitutional defects for the g allotrope. The results for vacancies agree very well with experimental and previous computational studies. The most probable self interstitial site in g U is the (110) dumbbell, and the most probable defect location for dilute Zr in g U is the substitutional site. This is the first detailed study of self defects in the bcc allotrope of U and also the first comprehensive study of dilute Zr defects in g U.", "author_names": [ "Benjamin W Beeler", "Brian Good", "Sergey N Rashkeev", "Chaitanya Deo", "Michael I Baskes", "Maria A Okuniewski" ], "corpus_id": 42274841, "doc_id": "42274841", "n_citations": 52, "n_key_citations": 0, "score": 0, "title": "First principles calculations for defects in U.", "venue": "Journal of physics. Condensed matter an Institute of Physics journal", "year": 2010 }, { "abstract": "Abstract The CASTEP code for first principles electronic structure calculations will be described. A brief, non technical overview will be given and some of the features and capabilities highlighted. Some features which are unique to CASTEP will be described and near future development plans outlined.", "author_names": [ "Stewart J Clark", "Matthew D Segall", "Chris J Pickard", "Philip Hasnip", "Matt Probert", "Keith Refson", "Mike C Payne" ], "corpus_id": 13847393, "doc_id": "13847393", "n_citations": 6917, "n_key_citations": 109, "score": 0, "title": "First principles methods using CASTEP", "venue": "", "year": 2005 }, { "abstract": "First principles calculations have evolved from mere aids in explaining and supporting experiments to powerful tools for predicting new materials and their properties. In the first part of this review we describe the state of the art computational methodology for calculating the structure and energetics of point defects and impurities in semiconductors. We will pay particular attention to computational aspects which are unique to defects or impurities, such as how to deal with charge states and how to describe and interpret transition levels. In the second part of the review we will illustrate these capabilities with examples for defects and impurities in nitride semiconductors. Point defects have traditionally been considered to play a major role in wide band gap semiconductors, and first principles calculations have been particularly helpful in elucidating the issues. Specifically, calculations have shown that the unintentional n type conductivity that has often been observed in as grown GaN cannot be a.", "author_names": [ "Chris G van de Walle", "Jorg Neugebauer" ], "corpus_id": 17667822, "doc_id": "17667822", "n_citations": 2094, "n_key_citations": 34, "score": 0, "title": "First principles calculations for defects and impurities: Applications to III nitrides", "venue": "", "year": 2004 }, { "abstract": "Abstract The title problem concerns two isotropic phases firmly bonded together to form a mixture with any concentrations. An elementary account of several theoretical methods of attack is given, among them the derivation of inequalities between various moduli. The approach is completely general and exact. Additionally, the problem is fully solved when the phases have equal rigidities but different compressibilities, the geometry being entirely arbitrary.", "author_names": [ "Rodney Hill" ], "corpus_id": 120026916, "doc_id": "120026916", "n_citations": 3647, "n_key_citations": 234, "score": 0, "title": "Elastic properties of reinforced solids: some theoretical principles", "venue": "", "year": 1963 }, { "abstract": "Preface Numerical simulation of intergranular and transgranular crack propagation in ferroelectric polycrystals Microstructure and stray electric fields at surface cracks in ferroelectrics Double kink mechanisms for discrete dislocations in BCC crystals The expanding spherical inhomogeneity with transformation strain A new model of damage: a moving thick layer approach On configurational forces at boundaries in fracture mechanics HotQC simulation of nanovoid growth under tension in copper Coupled phase transformations and plasticity as a field theory of deformation incompatibility Continuum strain gradient elasticity from discrete valence force field theory for diamond like crystals", "author_names": [ "Toshio Mura", "D M Barnett" ], "corpus_id": 119513520, "doc_id": "119513520", "n_citations": 4744, "n_key_citations": 321, "score": 0, "title": "Micromechanics of defects in solids", "venue": "", "year": 1982 }, { "abstract": "The first principles calculations have been performed to investigate the ground state properties of monoperiodic boron nitride (BN) TiO2, and SrTiO3 single walled nanotubes (SW NTs) containing extrinsic point defects. The hybrid exchange correlation functionals PBE, B3LYP, and B3PW within the framework of density functional theory (DFT) have been applied for large scale ab initio calculations on NTs with the following substitutional impurities: AlB, PN, GaB, AsN, InB, and SbN in the BN NT, as well as CO, NO, SO, and FeTi in the TiO2 and SrTiO3 NTs, respectively. The variations in formation energies obtained for equilibrium defective nanostructures allow us to predict the most stable compositions, irrespective of the changes in growth conditions. The changes in the electronic structure are analyzed to show the extent of localization of the midgap states induced by defects. Finally, the electronic charge redistribution was calculated in order to explore the intermolecular properties, which show how the reactivity of the NTs under study was affected by doping and orbital hybridization.", "author_names": [ "Yuri F Zhukovskii", "Sergei Piskunov", "Jevgenijs Begens", "Jurijs Kazerovskis", "Oleg Lisovski" ], "corpus_id": 56189251, "doc_id": "56189251", "n_citations": 14, "n_key_citations": 1, "score": 0, "title": "First principles calculations of point defects in inorganic nanotubes", "venue": "", "year": 2013 }, { "abstract": "The characterization of native point defects in ZnO is still a question of debate. For example, experimental evidence for ZnO with an excess of Zn is inconclusive as to whether the dominant defects are metal interstitials or oxygen vacancies. This information is essential to understand the behavior of the material and to tailor its numerous technological applications. We use the first principles pseudopotential method to determine the electronic structure, atomic geometry, and formation energy of native point defects in ZnO. Interstitials, vacancies, and antisites in their relevant charge states are considered and the effects of dopants are also discussed. The results show that both the Zn and O vacancies are the relevant defects in ZnO. We also propose a possible transition mechanism and defect center responsible for the experimentally observed green luminescence.", "author_names": [ "Adrian Kohan", "Gerbrand Ceder", "Dane Morgan", "Chris G van de Walle" ], "corpus_id": 9581756, "doc_id": "9581756", "n_citations": 1450, "n_key_citations": 12, "score": 0, "title": "First principles study of native point defects in ZnO", "venue": "", "year": 2000 }, { "abstract": "Abstract We discuss the present status of the first principles electronic structure calculations for defect energies in metals. The calculations apply density functional theory in the generalized gradient approximation of Perdew and Wang, together with a full potential version of Korringa Kohn Rostoker Green's function method, developed by the Julich group. It is shown that: (1) the present calculations reproduce very well the experimental results for vacancy formation energies in metals, as well as the bulk properties such as equilibrium lattice parameters and bulk moduli of metals; and (2) the type of the phase diagram of a binary A B alloy can be characterized by the interaction energies between a pair of impurity B (A) atoms in the host metal A (B) The observed temperature dependence of the solid solubility limit of Rh in Pd is also reproduced very well by the free energy calculations based on the cluster variation method with the pair (up to the eighth neighbor) and many body (up to a tetrahedron of first nearest neighbors) interaction energies, all of which are determined by the present first principles calculations.", "author_names": [ "Mitsuhiro Asato", "Toshiya Mizuno", "Toshiharu Hoshino", "K Masuda-Jindo", "Kazuto Kawakami" ], "corpus_id": 97173034, "doc_id": "97173034", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "First principles calculations for point defect energies in metals and phase diagrams of binary alloys", "venue": "", "year": 2001 } ]

[ { "abstract": "Abstract Inspired by the WO3 transition metal semiconductor, a simple liquid phase WO3 coating strategy is introduced to improve the surface stability of LiNi0.5Co0.2Mn0.3O2. The electrochemical performance of WO3 coated LiNi0.5Co0.2Mn0.3O2 is improved at both a high cut off voltage (4.5 V) and high temperature (50 degC) With the WO3 (0.6 wt% coating amount optimized, the material capacity retention is maintained at 138 mAh g 1 and 170.9 mAh g 1 at 25 degC and 50 degC after 200 cycles compared with 107.8 mAh g 1 and 143.9 mAh g 1, respectively, for pristine NCM523. The WO3 coated sample also exhibits a better rate capability, maintaining 126 mAh g 1 at 25 degC in the voltage range of 3 4.5 V at the current density of 5 C. The enhanced properties of the WO3 coated LiNi0.5Co0.2Mn0.3O2 due to the WO3 coating layer result from the interface that prevents immediate contact between the electrolyte and the active material as well as the lower polarization and electrochemical resistance of the battery. SEM, TEM, XPS and EIS further reveal these improved electrochemical performances, which indicate the success of the approach for regenerating NCM523.", "author_names": [ "Yulin He", "Yingtao Li", "Yaochun Liu", "Nianchun Yao", "Jiamei Li", "Yang Liu" ], "corpus_id": 212885737, "doc_id": "212885737", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Enhancement of the high voltage electrochemical performance of an LiNi0.5Co0.2Mn0.3O2 cathode via WO3 coating", "venue": "", "year": 2020 }, { "abstract": "LiNi0.8Co0.1Mn0.1O2 cathode material was successfully modified by using a wet chemical route to coat WO3. The microstructures, morphologies, crystal structures, elemental distributions and ionic valence of the prepared cathode materials were carefully analyzed by SEM, EDS, TEM, HRTEM, XRD and XPS. The results indicated that the surface of LiNi0.8Co0.1Mn0.1O2 was uniformly covered by WO3 particles, and a small amount of W could enter to the lattice of LiNi0.8Co0.1Mn0.1O2. The WO3 coating could prohibit the corrosion of HF and some side reactions for the cathode material during long cycles, thus greatly improving the electrochemical performance and the structural stability of LiNi0.8Co0.1Mn0.1O2. Among the examined LiNi0.8Co0.1Mn0.1O2 cathode materials, 1.0 wt% WO3 coated LiNi0.8Co0.1Mn0.1O2 has the best initial discharge capacity (185.1 mAh g and an excellent capacity retention (93.2% after 100 cycles at 1 C.", "author_names": [ "C Xiong" ], "corpus_id": 225302412, "doc_id": "225302412", "n_citations": 4, "n_key_citations": 0, "score": 2, "title": "Enhanced Electrochemical Performance of LiNi0.8Co0.1Mn0.1O2 Cathode Material for lithium ion batteries by WO3 surface coating", "venue": "", "year": 2020 }, { "abstract": "Surface coating and ion doping are of great significance for improving the electrochemical performance of cathode materials for lithium ion batteries. In this study, WO3 coated and Mg2+ doped LiNi0.8Co0.1Mn0.1O2 cathode materials were successfully synthesised by the coprecipitation and wet coating methods. X ray diffraction and energy dispersive X ray spectroscopy confirmed that the synthesised material was NCM811 with a good layered structure and Mg2+ doped into it. X ray photoelectron spectroscopy revealed that W6+ mainly existed on the surface of the material, while morphological analysis revealed a uniform WO3 coating on the material surface. Electrochemical performance of the material suggested that the modification by suitable materials synergistically stabilised the material structure and suppressed side reactions. Capacity retention of the dual modified material at 25 degC after 100 cycles at 1 C rate was as high as 73.5% which is considerably higher than that of the raw materials (53.6%", "author_names": [ "Zhongliang Xiao", "Chengfeng Zhou", "Zhong Cao", "Peng Jiang" ], "corpus_id": 232246874, "doc_id": "232246874", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Dual modification of WO3 coating and Mg doping on LiNi0.8Co0.1Mn0.1O2 cathodes for enhanced electrochemical performance at high voltage", "venue": "Ionics", "year": 2021 }, { "abstract": "Abstract The g WO3/Li2WO4 composite coated and spinel embedded Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode is successfully synthesized via a simple wet coating process. A series of synthesized materials were characterized by X ray diffraction (XRD) field emission scanning electron microscopy (FE SEM) high resolution transmission electron microscope (HR TEM) Raman and X ray photoelectron spectroscopy (XPS) g WO3/Li2WO4 composite layer was successfully coated on the surface of Li rich Mn based materials and the spinel structure was also formed during the modification process. Charge discharge measurements indicate that the modified samples show an enhanced cyclic properties and rate capability. After the modification process, the initial coulombic efficiency increased to 89.3% for 7 wt W composite coated sample with the lowest capacity loss of 33.5 mAh g 1. Particularly, 5 wt W composite coated sample shows the best capacity retention of 88.0% at 100 mA g 1 with the discharge capacity of 233.5 mAh g 1 and excellent rate capability with the discharge capacity of 173.0 mAh g 1 at 800 mA g 1. The improvements in electrochemical properties and structural stability were mainly due to both g WO3/Li2WO4 coating layer and the spinel phase formed during the modification.", "author_names": [ "Fanbo Meng", "Huajun Guo", "Zhixing Wang", "Guochun Yan", "Xinhai Li" ], "corpus_id": 139469245, "doc_id": "139469245", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Modification by simultaneously g WO3/Li2WO4 composite coating and spinel structure formation on Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode via a simple wet process", "venue": "Journal of Alloys and Compounds", "year": 2019 }, { "abstract": "Abstract Nano sized TiO 2 /WO 3 bilayer coatings were prepared on type 304 stainless steel substrate by sol gel method. The performance of photo electrochemical and photogenerated cathode protection of the coating was investigated by the electrochemical method. The results show that the bilayer coating with four TiO 2 layers and three WO 3 layers exhibits the highest photo electrochemical efficiency and the best corrosion resistance property. Type 304 stainless steel with the coating can maintain cathode protection for 6 h in the dark after irradiation by UV illumination for 1 h. In addition, the mechanism of the photogenerated cathode protection for the bilayer coating was also explored.", "author_names": [ "Min-jie Zhou", "Zhenou Zeng", "Li Zhong" ], "corpus_id": 95066785, "doc_id": "95066785", "n_citations": 63, "n_key_citations": 1, "score": 0, "title": "Photogenerated cathode protection properties of nano sized TiO2/WO3 coating", "venue": "", "year": 2009 }, { "abstract": "Abstract Despite Nickel rich materials have all the advantages of high capacity, long cycle life and low cost, there is still a disadvantage that the capacity decreases rapidly as the number of cycles increases. In order to solve this problem, WO3 was uniformly coated on the surface of LiNi0.6Co0.2Mn0.2O2 cathode materials by wet coating, and its cycling performance was greatly improved with the higher capacity. The coated materials were analyzed by X ray diffraction(XRD) Scanning electron microscope (SEM) high resolution Transmission electron microscopy (TEM) and X ray photoelectron spectroscopy(XPS) The results showed that the coating thickness was around 3.15 nm, and some tungsten ions were doped into the lattice of the near surface area of the LiNi0.6Co0.2Mn0.2O2 material. In addition, the results of charge discharge test showed that 1 wt%WO3 coating LiNi0.6Co0.2Mn0.2O2 had the best performance, and delivered a discharge capacity of 140 mAh g 1 (the capacity retention rate is 84.8% in the potential interval of 2.8 4.3 V at 1 C (1 C 165 mA g 1) after 200 cycles, while the bare cathode material only delivered a discharge capacity of 120 mAhg 1 (the capacity retention rate is 75% The phenomenon indicates that the WO3 coating plays a role in inhibiting the harmful side reactions between the cathode material and the electrolyte, improving the electrochemical and structure stability of LiNi0.6Co0.2Mn0.2O2 cathode materials.", "author_names": [ "Guowen Song", "Hui Zhong", "Yanyang Dai", "Xiangyang Zhou", "Juan-Yu Yang" ], "corpus_id": 139382872, "doc_id": "139382872", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "WO3 membrane encapsulated layered LiNi0.6Co0.2Mn0.2O2 cathode material for advanced Li ion batteries", "venue": "Ceramics International", "year": 2019 }, { "abstract": "Abstract WO3 coated Li1.2Ni0.2Mn0.6O2 cathode materials have been synthesized by using co precipitation method along with a liquid evaporation coating process. Investigations via X ray diffraction (XRD) scanning electron microscopy (SEM) transmission electron microscopy (TEM) and X ray photoelectron spectroscopy (XPS) reveal that a WO3 layer is uniformly distributed on the surface of bulk Li1.2Ni0.2Mn0.6O2. After coating appropriate amount of WO3, the Li rich cathode materials exhibit improved electrochemical performance. In particular, the 2 wt% WO3 coated sample (WO3 0.02 LLNMO) can deliver an initial discharge capacity of 252.2 mA h g 1 with a low irreversible capacity loss of 44.6 mA h g 1 and remarkable cycling stability of 97% capacity retention after 100 cycles at a current density of 52 mA g 1. This is mainly due to the effects of the WO3 coating layer which can suppress the initial activation of Li2MnO3 and improve the stability of surface structure of Li rich materials by protecting it from corrosion by HF and other side reactions.", "author_names": [ "Kunchang Mu", "Yanbing Cao", "Guo-rong Hu", "Ke Du", "Hao Yang", "Zhanggen Gan", "Zhong-dong Peng" ], "corpus_id": 102675053, "doc_id": "102675053", "n_citations": 38, "n_key_citations": 0, "score": 0, "title": "Enhanced electrochemical performance of Li rich cathode Li1.2Ni0.2Mn0.6O2 by surface modification with WO3 for lithium ion batteries", "venue": "", "year": 2018 }, { "abstract": "Abstract This paper reports the enhancement of the electrochromic properties of a tungsten trioxide (WO3) based electrode through the synthesis of hierarchical zinc oxide (ZnO) nanobricks (ZnBs) The two step hydrothermal method and the radio frequency (RF) sputtering were used for the growth of highly conductive ZnBs and the coating of electrochromic WO3 film, respectively. Three different structures were prepared: an electrode without ZnBs, electrode with single layered and electrode with double layered ZnBs. The electrochromic properties of the electrode were improved significantly attributing to the preparation of double layered ZnBs. Compared to the electrode without ZnBs, the electrode with double layered ZnBs showed a fast response at coloring (response time reduced from 15.9 s to 12.8 s, speeding by 19.5% with an enhanced coloration efficiency (from 4.33 cm2 C 1 increasing to 18.28 cm2 C 1, improving by 4.2 fold) After repeating the redox for 2000 cycles, the peak current densities of anode and cathode were 60.3% and 52.2% respectively of their initial densities. Stable electrochromic performance of the electrode was achieved.", "author_names": [ "Su-Hua Yang", "Jiahua Yang" ], "corpus_id": 219791401, "doc_id": "219791401", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Enhancement on electrochromic properties of WO3 based electrode prepared with hierarchical ZnO nanobricks", "venue": "", "year": 2020 }, { "abstract": "Abstract Lateral Programmable Metallization Cell (PMC) structures rely on metal electrodeposition in a long channel consisting of a solid electrolyte layer between an anode and a cathode. Integration of these devices with CMOS circuitry demands using materials such as copper and tungsten for the electrodes, and an oxide of tungsten (WO3) doped with Cu for the electrolyte. However, low diffusivity of Cu in WO3 and its high resistivity results in a slow electrodeposition process. Our solution to this problem involves the use of a Cu2O/Cu WO3 bilayer, formed by oxidation of a thin Cu film on a WO3 layer and a simultaneous diffusion of Cu into the WO3 at moderate temperatures. This creates a Cu WO3 solid electrolyte with a semiconducting Cu2O coating that brings electrons to where the ions are most abundant and thereby greatly increases the electrodeposition rate. In this paper, an investigation of thin film Cu oxidation is presented along with the diffusion kinetics of Cu in WO3. The Cu was oxidized in air to form Cu2O with an activation energy of 0.70 eV. The diffusion analysis showed activation energy of Cu diffusion in WO3 was 0.74 eV, which we believe is the first time this value has been reported.", "author_names": [ "Mehmet B Balaban", "Ninad Chamele", "S Swain", "Yago Gonzalez-Velo", "Michael N Kozicki" ], "corpus_id": 219907583, "doc_id": "219907583", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Fabrication and characterization of Cu2O/Cu WO3 bilayers for lateral programmable metallization cells", "venue": "", "year": 2020 }, { "abstract": "Construction of multifunctional photoelectrochemical energy devices is of great importance to energy saving. In this study, we have successfully prepared a mesoporous WO3 film on FTO glass via a facile dip coating sol gel method; the designed mesoporous WO3 film exhibited advantages including high transparency, good adhesion and high porosity. Also, multifunctional integrated energy storage and optical modulation ability are simultaneously achieved by the mesoporous WO3 film. Impressively, the mesoporous WO3 film exhibits a noticeable electrochromic energy storage performance with a large optical modulation up to 75.6% at 633 nm, accompanied by energy storage with a specific capacity of 75.3 mA h g 1. Furthermore, a full electrochromic energy storage window assembled with the mesoporous WO3 anode and PANI nanoparticle cathode is demonstrated with large optical modulation and good long term stability. Our research provides a new route to realize the coincident utilization of optical electrochemical energy.", "author_names": [ "Wei-qi Wang", "Xiufang Wang", "Xinhui Xia", "Zhujun Yao", "Yu Zhong", "Jiangping Tu" ], "corpus_id": 4980066, "doc_id": "4980066", "n_citations": 66, "n_key_citations": 0, "score": 0, "title": "Enhanced electrochromic and energy storage performance in mesoporous WO3 film and its application in a bi functional smart window.", "venue": "Nanoscale", "year": 2018 } ]

[ { "abstract": "Lately, the integration of two dimensional materials into semiconductor devices has allowed the modification of their effective index by simply applying a modest voltage (between 0 and 3 volts) In this work, we present a device composed of two evanescently coupled silicon microring resonators where both rings have a graphene layer on top. This design is aimed to produce frequency combs with transmission characteristics controlled upon voltage application to the graphene layer. We numerically analyze the device response as a function of the incident wavelength and applied voltage. The results showed a low input intensity (0.6 GW/cm2) needed and a rapid response time (0.1 ms) in comparison to devices controlled by heat injection. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (130.0130) Integrated optics; (230.0230) Optical devices. (190.0190) Nonlinear optics. References and links 1. Z. Sun, A. Martinez, and F. Wang, \"Optical modulators with 2D layered materials,\" Nat. Photonics 10, 227 238 (2016) 2. T. Low, A. Chaves, J. D. Caldwell, A. Kumar, N. X. Fang, P. Avouris, T. F. Heinz, F. Guinea, L. Martin Moreno, and F. Koppens, \"Polaritons in layered two dimensional materials,\" Nat. Mater. 16, 182 (2017) 3. K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, \"Electric field effect in atomically thin carbon films,\" Science 306, 666 669 (2004) 4. A. K. Geim and K. S. Novoselov, \"The rise of graphene,\" Nat Mater 6, 183 (2007) 5. F. Schwierz, \"Graphene transistors,\" Nat. Nanotechnol. 5, 487 496 (2010) 6. F. Bonaccorso, Z. Sun, T. Hasan, and A. Ferrari, \"Graphene photonics and optoelectronics,\" Nat. Photonics 4, 611 622 (2010) 7. L. Liao, Y. C. Lin, M. Bao, R. Cheng, J. Bai, Y. Liu, Y. Qu, K. L. Wang, Y. Huang, and X. Duan, \"High speed graphene transistors with a self aligned nanowire gate,\" Nature 467, 305 308 (2010) 8. P. Avouris, Z. Chen, and V. Perebeinos, \"Carbon based electronics,\" Nat. Nanotechnol. 2, 605 615 (2007) 9. Y. Fan, N. H. Shen, T. Koschny, and C. M. Soukoulis, \"Tunable terahertz meta surface with graphene cut wires,\" ACS Photonics 2, 151 156 (2015) 10. T. Low and P. Avouris, \"Graphene plasmonics for terahertz to mid infrared applications,\" ACS Nano 8, 1086 1101 (2014) 11. Y. Fan, F. Zhang, Q. Zhao, Z. Wei, and H. Li, \"Tunable terahertz coherent perfect absorption in a monolayer graphene,\" Opt. Lett. 39, 6269 6272 (2014) 12. Y. Fan, N. H. Shen, F. Zhang, Z. Wei, H. Li, Q. Zhao, Q. Fu, P. Zhang, T. Koschny, and C. M. Soukoulis, \"Electrically tunable Goos Hanchen effect with graphene in the terahertz regime,\" Adv. Opt. Mater. 4, 1824 1828 (2016) 13. R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. Peres, and A. K. Geim, \"Fine structure constant defines visual transparency of graphene,\" Science 320, 1308 (2008) 14. K. F. Mak, M. Y. Sfeir, Y. Wu, C. H. Lui, J. A. Misewich, and T. F. Heinz, \"Measurement of the optical conductivity of graphene,\" Phys. Rev. Lett. 101, 196405 (2008) 15. V. Sorianello, G. De Angelis, T. Cassese, M. Midrio, M. Romagnoli, M. Mohsin, M. Otto, D. Neumaier, I. Asselberghs, J. Van Campenhout, and C. Huyghebaert, \"Complex effective index in graphene silicon waveguides,\" Opt. Express Vol. 26, No. 12 11 Jun 2018 OPTICS EXPRESS 15490 #322741 https:/doi.org/10.1364/OE.26.015490 Journal (c) 2018 Received 21 Feb 2018; revised 17 Apr 2018; accepted 17 Apr 2018; published 6 Jun 2018 24, 29984 29993 (2016) 16. J. Capmany, D. Domenech, and P. Munoz, \"Silicon graphene waveguide tunable broadband microwave photonics phase shifter,\" Opt. Express 22, 8094 8100 (2014) 17. J. Capmany, D. Domenech, and P. Munoz, \"Silicon graphene Bragg gratings,\" Opt. Express 22, 5283 5290 (2014) 18. S. A. Diddams, T. Udem, J. Bergquist, E. Curtis, R. Drullinger, L. Hollberg, W. M. Itano, W. Lee, C. Oates, K. Vogel, and D. J. Wineland, \"An optical clock based on a single trapped 199hg+ ion,\" Science 293, 825 828 (2001) 19. M. Murphy, T. Udem, R. Holzwarth, A. Sizmann, L. Pasquini, C. Araujo Hauck, H. Dekker, S. D'Odorico, M. Fischer, T. Hansch, and A. Manescau, \"High precision wavelength calibration of astronomical spectrographs with laser frequency combs,\" Mon. Not. R. Astron. Soc. 380, 839 847 (2007) 20. T. Steinmetz, T. Wilken, C. Araujo Hauck, R. Holzwarth, T. W. Hansch, L. Pasquini, A. Manescau, S. D'Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, \"Laser frequency combs for astronomical observations,\" Science 321, 1335 1337 (2008) 21. C. H. Li, A. J. Benedick, P. Fendel, A. G. Glenday, F. X. Kartner, D. F. Phillips, D. Sasselov, A. Szentgyorgyi, and R. L. Walsworth, \"A laser frequency comb that enables radial velocity measurements with a precision of 1 cm s 1,\" Nature 452, 610 612 (2008) 22. S. A. Diddams, L. Hollberg, and V. Mbele, \"Molecular fingerprinting with the resolved modes of a femtosecond laser frequency comb,\" Nature 445, 627 630 (2007) 23. C. Gohle, T. Udem, M. Herrmann, J. Rauschenberger, R. Holzwarth, H. A. Schuessler, F. Krausz, and T. W. Hansch, \"A frequency comb in the extreme ultraviolet,\" Nature 436, 234 237 (2005) 24. R. J. Jones, K. D. Moll, M. J. Thorpe, and J. Ye, \"Phase coherent frequency combs in the vacuum ultraviolet via high harmonic generation inside a femtosecond enhancement cavity,\" Phys. Rev. Lett. 94, 193201 (2005) 25. F. Keilmann, C. Gohle, and R. Holzwarth, \"Time domain mid infrared frequency comb spectrometer,\" Opt. Lett. 29, 1542 1544 (2004) 26. I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, \"Rapid and precise absolute distance measurements at long range,\" Nat. Photonics 3, 351 356 (2009) 27. R. W. Boyd, Nonlinear optics (Academic Press, 2003) 28. G. P. Agrawal, Nonlinear fiber optics (Academic Press, 2007) 29. T. J. Kippenberg, R. Holzwarth, and S. Diddams, \"Microresonator based optical frequency combs,\" Science 332, 555 559 (2011) 30. T. Herr, K. Hartinger, J. Riemensberger, C. Wang, E. Gavartin, R. Holzwarth, M. Gorodetsky, and T. Kippenberg, \"Universal formation dynamics and noise of kerr frequency combs in microresonators,\" Nat. Photonics 6, 480 487 (2012) 31. A. A. Savchenkov, A. B. Matsko, V. S. Ilchenko, I. Solomatine, D. Seidel, and L. Maleki, \"Tunable optical frequency comb with a crystalline whispering gallery mode resonator,\" Phys. Rev. Lett. 101, 093902 (2008) 32. I. S. Grudinin, N. Yu, and L. Maleki, \"Generation of optical frequency combs with a caf 2 resonator,\" Opt. Lett. 34, 878 880 (2009) 33. W. Liang, A. Savchenkov, A. Matsko, V. Ilchenko, D. Seidel, and L. Maleki, \"Generation of near infrared frequency combs from a MgF2 whispering gallery mode resonator,\" Opt. Lett. 36, 2290 2292 (2011) 34. C. Wang, T. Herr, P. Del'Haye, A. Schliesser, R. Holzwarth, T. W. Haensch, N. Picque, and T. Kippenberg, \"Midinfrared frequency combs based on microresonators,\" in Proceedings of Optical Society of America Conference CLEO: Science and Innovations (Optical Society of America, 2011) p. PDPA4. 35. I. H. Agha, Y. Okawachi, M. A. Foster, J. E. Sharping, and A. L. Gaeta, \"Four wave mixing parametric oscillations in dispersion compensated high q silica microspheres,\" Phys. Rev. A 76, 043837 (2007) 36. L. Razzari, D. Duchesne, M. Ferrera, R. Morandotti, S. Chu, B. Little, and D. Moss, \"Cmos compatible integrated optical hyper parametric oscillator,\" Nat. Photonics 4, 41 45 (2010) 37. J. S. Levy, A. Gondarenko, M. A. Foster, A. C. Turner Foster, A. L. Gaeta, and M. Lipson, \"Cmos compatible multiple wavelength oscillator for on chip optical interconnects,\" Nat. Photonics 4, 37 40 (2010) 38. M. A. Foster, J. S. Levy, O. Kuzucu, K. Saha, M. Lipson, and A. L. Gaeta, \"Silicon based monolithic optical frequency comb source,\" Opt. Express 19, 14233 14239 (2011) 39. D. Braje, L. Hollberg, and S. Diddams, \"Brillouin enhanced hyperparametric generation of an optical frequency comb in a monolithic highly nonlinear fiber cavity pumped by a cw laser,\" Phys. Rev. Lett 102, 193902 (2009) 40. Y. Yi, P. Pignalosa, and D. Wu, \"Tunable and ultra small graphene integrated silicon racetrack micro resonator,\" IEEE IEEE J. Sel. Top. Quantum Electron. 23, 1 6 (2017) 41. P. A. Costanzo Caso, Y. Jin, S. Granieri, and A. Siahmakoun, \"Optical bistability in a nonlinear soa based fiber ring resonator,\" J. Nonlinear Opt. Phys. Mater.20, 281 292 (2011) 42. S. Rabal, L. A. Bulus Rossini, and P. A. Costanzo Caso, \"Control strategy of true time delay lines,\" Fiber Integrated Opt. 38, 38 58 (2016) 43. P. Del Haye, T. Herr, E. Gavartin, M. Gorodetsky, R. Holzwarth, and T. J. Kippenberg, \"Octave spanning tunable frequency comb from a microresonator,\" Phys. Rev. Lett. 107, 063901 (2011) 44. H. Jung, C. Xiong, K. Y. Fong, X. Zhang, and H. X. Tang, \"Optical frequency comb generation from aluminum nitride microring resonator,\" Opt. Lett. 38, 2810 2813 (2013) 45. X. Xue, Y. Xuan, P. H. Wang, J. Wang, D. E. Leaird, M. Qi, and A. M. Weiner, \"Tunable frequency comb generation from a microring with a thermal heater,\" in Proceedings of Optical Society of America Conference CLEO: Science Vol. 26, No. 12 11 Jun 2018 OPTICS EXPRESS 15491", "author_names": [ "", "Chadli A", "P V" ], "corpus_id": 53703060, "doc_id": "53703060", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Manipulation of extinction features in frequency combs through the usage of graphene", "venue": "", "year": 2018 }, { "abstract": "The cell phone market is growing on a daily basis as the demand increases globally. However, the availability of the internet has been a major driver for the demand as people use it to access vital information and communicate through social media platforms. The development has enjoyed its proportionate share or destructions as both adolescents and adults are addicted to using the gadgets. It is evident that the number of people using phones is increasing, and this could be disastrous if the right measures are not taken early. As a result, some people have to gamble with their health at the expense of lengthy time on the phone and lack time to interact. It is evident that people addicted to cellphone usage are likely to use most of their time sleeping or sitting. Lack of adequate exercise or poor posters contributes to health issues such as obesity, back pain, or heart diseases. Exposure to the excessive light emitted by phone screens can affect the users' visual ability. There is adequate literature on this topic, and at least six peer reviewed journals were used to get results and discussions. The results revealed there were high chances of depression for cell phone addicts. Cases of antisocial behaviors have been noted in some people addicted to the phone use, as they prefer utilizing much time on a phone instead of interacting with close friend and family. The incidence of some adolescents being misled by information got from the internet is increasing. A case in point was the infamous 'blue whale challenge' that misled some adolescents to the extent of committing suicide. In other cases, the reasoning ability is affected because some people use a phone for a long time and they do not have time for adequate sleep. Consequently, they are likely to be exposed to stress and depression since their brains fail to concentrate or function properly. In case of students, they will end up failing in school and have psychological issues that can lead to depression. As a result, further studies should be conducted to determine the most appropriate preventive measures.", "author_names": [ "George B Clairmont", "Bernice Lf" ], "corpus_id": 150523509, "doc_id": "150523509", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Cell Phone Addiction and the Link to Depression in Adolescents and Adults", "venue": "", "year": 2018 }, { "abstract": "This paper concentrates on the worldview of portable distributed computing, which contains preferences of versatile processing, distributed computing, and systems administration. We audit the significant advantages offered to portable distributed computing by the fifth era remote innovation, including the parts of heterogeneous network, gadget to gadget and machine to machine correspondences, and additionally vitality effectiveness. Our work closes by uncovering open difficulties and alluring headings for further research around there. Keywords mobile cloud computing; fifth generation (5G) wireless technology; heterogeneous networks (HetNets) device to device (D2D) communications; energy efficiency, Internet of Things (IoT) Internet of Services (IoS) I. MODERN MOBILE CLOUD COMPUTING Today, progressively fit cell phones, spoke to by cutting edge advanced cells and tablets, are utilized to help individuals in their day by day schedules, from correspondence and social association to putting away and handling their essential private data. With handheld gadget industry now turning into a 150 billion dollar business, we witness phenomenal differing qualities of portable applications and administrations crosswise over both customer and venture markets. To this end, versatile figuring has officially formed into a critical innovation permitting us to get to data and information whenever, anyplace. Be that as it may, given restricted data transmission, battery life, and capacity limit of current client gear, distributed computing has as of late risen as the collection of registering ability to expand the contemporary processing framework. Distributed computing for the most part offers on interest provisioning of different applications, stages, and heterogeneous figuring frameworks [1] Given the size of its utilization today, from diversion, gaming, travel, and news to human services, business, and long range informal communication, we anticipate that distributed computing will in the end develop into the Internet of Services (IoS) [2] With IoS, everything that exists on the Internet today might be spoken to as an administration and afterward conveyed to the end client. Together with Internet by and for the general population and the Internet of Things (IoT) the IoS is accepted to prepare for the future arranged society, where \"individuals, learning, gadgets, and data are organized for the development of society, life, and RAVINDER REDDY SEELAM et al, International Journal of Computer Science and Mobile Computing, Vol.5 Issue.6, June2016, pg. 538 544 (c) 2016, IJCSMC All Rights Reserved 539 business\" [3] The vital auxiliary segments of the IoS are (i) Software as a Service (SaaS) empowering on interest access to any application, (ii) Platform as a Service (PaaS) giving stage to development and conveyance of uses, and (iii) Infrastructure as a Service (IaaS) offering on interest registering systems administration, and capacity bases. At last, different applications will be conveyed as administrations over the IoS base, while the equipment and frameworks programming of server farms will be utilized to give those administrations. Here, a fundamental element for the cloud suppliers to keep up the versatility of their administrations and also to enhance the related operational effectiveness is the virtualization of cloud assets. Subsequently, cloud administrators progressively depend on product equipment usage by method for system capacity virtualization (NFV) and programming characterized organizing (SDN) Situated at the crossing point of portable figuring, distributed computing, and systems administration, versatile distributed computing (MCC) acquires the alluring advantages of portability, correspondence, and transportability [4] It guarantees to essentially develop the battery lifetime of versatile client gadgets, enhance their information stockpiling limit and preparing power, and expand the unwavering quality [5] In this manner, it does not shock anyone that cloud based versatile arrangements have developed into a 10billion dollar market having applications in picture and dialect handling, sharing Internet information, swarm processing, mixed media look, sensor information applications, and person to person communication. Sadly, unusual client development in versatile mists may prompt regular reconnections and thus brings along the real restrictions of MCC, for example, shaky availability, asset lack, and limited vitality supply [6].Therefore, considerable progress has to be made in communications technology before the MCC challenges could be met satisfactorily. Many, however, believe that recent advances in wireless connectivity hold a promise to mitigate the most pressing demands of MCC [7] In what follows, we review the latest developments in wireless communications technology and concentrate on its capabilities to unveil the full potential of future MCC. II. FIFTH GENERATION COMMUNICATIONS TECHNOLOGY Current remote frameworks are attempting to meet the foreseen speeding up in client movement request disturbed by the fast expansion in cloud based administrations and applications. With the normal 13 fold development of portable information throughout the following five years, versatile system administrators are tested with the need to altogether enhance limit and scope over their remote organizations. To increase the current cell innovation, portable industry is stepping in numerous parts of fifth era (5G) remote framework outline; a few of them abridged over the span of our survey A. Heterogeneous multi radio multi cell connectivity It is a typical conviction that 5G remote frameworks won't be a widespread one size fits all arrangement, but instead turn into a merged arrangement of different radio access advancements (RATs) coordinated under the control of the administrator's cell system. Thusly, the worldview of heterogeneous systems (HetNets) has been presented as a cutting edge organizing design (see Figure 1) empowering forceful limit and scope upgrades towards future 5G systems [8] Today, HetNets as of now contain a progressive arrangement of little cells, on different scales and by various RATs, for limit together with large scale cells for omnipresent scope, control coordination, and consistent portability [9] RAVINDER REDDY SEELAM et al, International Journal of Computer Science and Mobile Computing, Vol.5 Issue.6, June2016, pg. 538 544 (c) 2016, IJCSMC All Rights Reserved 540 Fig. 1. Envisioned architecture of a 5G wireless system. An imperative late pattern in HetNets is the expanding conjunction between cell (e.g. 3GPP LTE) and neighbourhood (e.g. IEEE 802.11 a.k.a. Wi Fi) [10] By complexity to cell innovation dwelling in costly authorized range, Wi Fi utilizes unlicensed recurrence groups and in this manner might be favoured for sharp offloading of the cell system activity [11] Extra advantages of Wi Fi stem from the way that it exists in the large number of structures (from traditional IEEE 802.11n and high rate 802.11ac arrangements, to mm Wave 802.11ad frameworks, to low control 802.11ah innovation) Persuaded initially by the administrators' longing to ease quick clog on their systems, the utilization of Wi Fi is, notwithstanding, liable to stay in the standard of 5G advancement, with incorporated little cells (utilizing co found LTE and Wi Fi interfaces) flooding the business sector soon. To encourage joining of Wi Fi under the control of the cell organize, the 3GPP models group is creating adaptable lower layer coordination instruments as of now for the Release 12 of LTE innovation. Such control methodology dwell on the radio access system (RAN) level and permit to, e.g. progressively adjust the stacking of the related RATs and even empower their synchronous operation, when client hardware transmits on a few radio interfaces [12] The fine grained control plans utilizing RAN level help are required to convey enhanced execution to future HetNets by improving them from multiple points of view, from cutting edge RAT revelation and ongoing system choice [13] to multi RAT radio asset administration, versatility, and session exchange capacities. B. Network assisted device to device communications While sending an expanding thickness of multi radio little cells turns into the standard bearing toward the 5G, system densification actually suggests extensive capital and operational uses to introduce and deal with the additional base stations. In this manner, thick HetNets may now and then require restrictive speculation from the system administrators subsequently making them look for option strategies to offload cell system movement. In addition, taking care of a system with multi RAT little cells of various sizes may acquire critical difficulties in cross cell impedance coordination, and also bring about exceptionally complex control methods for system help. Luckily, there is an option answer for offload a portion of the phone movement onto direct gadget to gadget (D2D) radio connections as these are ordinarily shorter and in this manner more frightfully proficient than the customary little cell associations [14] With a significant part of the present RAVINDER REDDY SEELAM et al, International Journal of Computer Science and Mobile Computing, Vol.5 Issue.6, June2016, pg. 538 544 (c) 2016, IJCSMC All Rights Reserved 541 versatile movement development originating from shared applications and administrations, which commonly include individuals in close nearness, the advantages of D2D interchanges for information offloading are turning out to be progressively alluring [15] While D2D based operation does not utilize broadband framework for exchanging client information, cell availability may in any case help by giving help gadget disclosure, D2D association foundation, and administration coherence. All things considered, D2D innovation can ease cell blockage without the expense of extra systems", "author_names": [ "Ravinder Reddy Seelam", "R Prakash Kolli", "Posinasetti Nageswara Rao", "K Bikshapati" ], "corpus_id": 212545363, "doc_id": "212545363", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Review of Future Mobile Cloud Computing with the help of 5G Wireless Technology", "venue": "", "year": 2016 }, { "abstract": "Variety of companies the usage of cloud computing has improved dramatically over the last few years because of the attractive capabilities including scalability, flexibility, fast start up and coffee expenses. offerings supplied over the net are ranging from the use of provider's software program and hardware to handling safety and other troubles. a number of the biggest challenges at this point are supplying privateness and data protection to subscribers of public cloud servers. An green encryption approach provided in this paper can be used for secure get admission to to and storage of data on public cloud server, moving and searching encrypted records via communique channels whilst shielding information confidentiality. security has come to be an critical and vital paradigm in information services that supplied by way of various clouds. information want to be stored and manipulated very confidentially and without information breach. Cloud computing presents a service based totally on net for several shared resources and system software program across diverse environment. For cozy cloud garage the method of encryption of the data to the customers for various desires has been introduced with the aid of the delegated access control approach. typically garage in public cloud requires excessive verbal exchange, heavy load due to maximum storage and high computational charges. on this paper, we're implementing multi cloud environment for secure garage where it acts as a public cloud and presents low fees, also it entails twolayer encryption over the information saved within the cloud. we are the use of an green AES algorithm which offers higher confidentiality and privateness for numerous users within the cloud and stores the statistics in multi clouds where the users can retrieve with the keys later while delegating it via get admission to manipulate from the cloud. Securities as well as expenses are the peak troubles in this area of studies and that they range considerably, depending on the vendor. To defend clouds, providers need to first secure virtualized datacenter assets, uphold person privateness, and hold records integrity. The authors propose using a consider overlay network over more than one facts centers to implement a reputation gadget for setting up agree with between service companies and statistics owners. statistics coloring and software program watermarking techniques shield shared facts gadgets and vastly dispensed software program modules. those techniques guard multi way authentications, enable unmarried sign on within the cloud, and tighten get right of entry to manage for sensitive statistics in both public and private clouds. The proposed model is exceedingly efficient and secures underneath current security models. The authors tried to study the threats and attacks that possibly launch in cloud computing records garage and proposed a safety mechanism. This paper offers a strong picture watermarking scheme based totally on a sample projection method. while we keep in mind the human visual system in our watermarking algorithm, we use the low frequency additives of image blocks for statistics hiding to attain excessive robustness in opposition to attacks. We use four samples of the approximation coefficients of the image blocks to construct a line segment inside the 2 D area. The slope of this line segment, that is invariant to the gain component, is employed for watermarking cause. We embed the watermarking code by using projecting the line section on some unique traces according to message bits. To design a most probability decoder, we compute the distribution of the slope of the embedding line segment for Gaussian samples. The performance of the proposed approach is analytically investigated and verified via several simulations. Experimental outcomes verify the validity of our model International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 03 Issue: 09 Sep 2016 www.irjet.net p ISSN: 2395 0072 (c) 2016, IRJET Impact Factor value: 4.45 ISO 9001:2008 Certified Journal Page 46 and its high robustness towards common attacks in evaluation with similar watermarking strategies which are invariant to the gain assault.", "author_names": [ "", "Mr B Kkaruppusamy" ], "corpus_id": 212578950, "doc_id": "212578950", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "RETRIEVING SECURE ENHANCED AES BASED WATERMARKING DATA COLORING IN CLOUD COMPUTING ATMOSPHERE", "venue": "", "year": 2016 }, { "abstract": "Despite two decades of empirical studies focusing on programmers and the problems with programming, usability of textual programming languages is still hard to achieve. Its younger relation, visual programming languages (VPLs) also share the same problem of poor usability. This research explores and investigates the usability issues relating to VPLs in order to suggest a set of design principles that emphasise usability. The approach adopted focuses on issues arising from the interaction and communication between the human (programmers) the computer (user interface) and the program. Being exploratory in nature, this PhD reviews the literature as a starting point for stimulating and developing research questions and hypotheses that experimental studies were conducted to investigate. However, the literature alone cannot provide a fully comprehensive list of possible usability problems in VPLs so that design principles can be confidently recommended. A commercial VPL was, therefore, holistically evaluated and a comprehensive list of usability problems was obtained from the research. Six empirical studies employing both quantitative and qualitative methodology were undertaken as dictated by the nature of the research. Five of these were controlled experiments and one was qualitative naturalistic. The experiments studied the effect of a programming paradigm and of representation of program flow on novices' performances. The results indicated superiority of control flow programs in relation to data flow programs; a control flow preference among novices; and in addition that directional representation does not affect performance while traversal direction does due to cognitive demands imposed upon programmers. Results of the qualitative study included a list of 145 usability problems and these were further categorised into ten problem areas. These findings were integrated with other analytical work based upon the review of the literature in a structured fashion to form a checklist and a set of design principles for VPLs that are empirically grounded and evaluated against existing research in the literature. Furthermore, an extended framework for Cognitive Dimensions of Notations is also discussed and proposed as an evaluation method for diagrammatic VPLs on the basis of the qualitative study. The above consists of the major findings and deliverables of this research. Nevertheless, there are several other findings identified on the basis of the substantial amount of data obtained in the series of experiments carried out, which have made a novel contribution to knowledge in the fields of Human Computer Interaction, Psychology of Programming, and Visual Programming Languages. Acknowledgements The journey to completing a PhD has not been a lonely path, as I was told when I started. Of course, there were times when I experienced intellectual loneliness, which was, perhaps, the feeling I most resented. But the world is not static, time passes, and new people come around. Only through this long journey have I had the opportunity to befriend and to be inspired by so many people from different professions, cultures, and expertise. They are my friends who, one way or another intellectually or not have been a part of this research and a part of the new me at the end of this journey. Firstly, I thank my long term teacher and mentor, Dave Sharp, for his faith in me and for always being supportive. I am indebted to my supervisors, Dr Jasna Kuljis and Professor Ray Paul, for their supervision and, in particular, for their patience in waiting for and reading the' Story' I specially thank all participants of my experiments at the University of Westminster, University of London (Goldsmiths campus) and Brunei University. In the early days of this research, my thanks go to Professor Thomas Green, who joyfully answered my questions both via emails and over dining tables. At Brunei, I thank Jacqueline Brodie and Chiladda Chennawasin, my PhD buddies who, frequently came to the rescue of my 999 'intellectual' calls. Those who inspired and helped me over the Atlantic via emails must also be acknowledged. I thank Professor Gitte Lindgaard of Carleton University, Canada. My mentor and friend, through emails at low and high times and, without whom, HE Plus may not have been born. I would also like to thank Dr Paul D. Tynan at Eastman Kodak in New York for sharing with me his professional experience. I was fortunate enough to gain confidence in a piece of my work in this research by having known Dr Patrick W. Jordan who shared my faith in the Immersion method. The list only gets longer and there seems not to be enough space to mention all who must be thanked. On the personal front, I thank Mano, Mina, Kana, and Seij i for putting up with my bad habit of working' an.vtime and anywhere Perhaps, they did not have a choice, but I am still grateful. There were others who helped shape the new me during this journey. Jacqueline, who arrived during my second year at Brunei kept me sane by distracting me with the fun of researching our shared interests. This distraction was an invaluable experience such that I gladly paid the price of a longer journey towards completing my PhD. Jacqueline, however, was not the only supporter of my mental well being, I also owe my sanity and fitness to Nick Adamou and his karate training, which I would have never tried had it not been for the monotonic lifestyle that I adopted during this journey. Finally, I thank you all for your serious effort in proofreading this thesis: Jacqueline Brodie, James Evans, Robert Scane, and Nick West. List of Publications 1. Brodie, 1. Chattratichart J. Perry, M. Scane, R. (2003) How age can inform the future design of mobile phone experience. In S. Constantine (Ed. Proceedings of the Human Computer Interaction International, HCll 2003, Volume 4 (pp.822 826) NJ:Lawrence Erlbaum Associates. 2. Chattratichart, J. (2003) Establishing Design Principles for Diagrammatic VPLs. In M. Rauterberg, M. Menozzi J. Wesson (Eds. Proceedings of the Xinth IFIP Te13 Conference on Human Computer Interaction, Interact 2003(pp. 948) Amsterdam: lOS Press. 3. Chattratichart, J. Brodie, 1. (2003a) HE Plus: Toward usage centered expert re\\'ie\\ for website design. In L. L. Constantine (Ed. Proceedings of/orUSE 2003, Second International Conference on Usage Centered Design (pp. 155 169) Massachusetts: Ampersand Press. 4. Chattratichart,1. Brodie, 1. (2003b) Envisioning a mobile phone for 'all' ages. In M. Rauterberg, M. Menozzi 1. Wesson (Eds. Proceedings of the Ninth IFIP Te13 Conference on Human Computer Interaction, Interact 2003 (pp. 725 728) Amsterdam: lOS Press. 5. Chattratichart,1. Brodie, J. (2003c) Inclusive phone design to bridge the age gap. In Proceedings of the Fourth Annual ACM SIGCHI NZ Conference on ComputerHuman Interaction, CHINZ 2003 (pp.III 115) ACM SIGCHI. 6. Chattratichart, 1. Brodie, J. (2003d) The age factor in the design equation of cell phones. In Proceedings of the 12th Annual Usability Professionals' Association Conference, UPA 2003. UPA. 7. Chattratichart, 1. Cave, D. Vaduva, A. (2003) Learning and doing 'expert evaluation' A teaching dilemma. In L. L. Constantine (Ed. Proceedings offorUSE 2003, Second International Conference on Usage Centered Design (pp. 27 35) Massachusetts: Ampersand Press. 8. Chattratichart,1. Jordan, P. W. (2003) Simulating 'lived' user experience Virtual immersion and inclusive design. In M. Rauterberg, M. Menozzi 1. Wesson (Eds. Proceedings of the Ninth IFIP Te13 Conference on Human Computer Interaction, Interact 2003 (pp. 721 725) Amsterdam: lOS Press. 9. Chattratichart, J. Turner, C. Brodie, 1. (2003) Exploring the total customer experience: Usability evaluations of (B2C) e commerce environments. In S. Minocha L. Dawson (Eds. Proceedings of Workshop 6, the Ninth IFIP Te13 Conference on Human Computer Interaction, Interact 2003 (pp. 4 5) The Open University. 10. Jordan, P. W. Chattratichart, J. (2003) Immersion and design Getting inside the user's mind. In Proceedings of the ICSID 2 Educational Conference, ICSID Design Congress 2003 (pp.48 52) IF International Forum Design GmbH. 11. Brodie, J. Chattratichart, 1. (2002) Contextualising heuristic evaluation to improve website appraisal. In Proceedings of the 11 th Annual Usability Professionals' Association Conference, UP A 2002 (pp. 51) UP A. 12. Chattratichart,1. Brodie, 1. (2002a) Establishing design guidelines for a better online shopping experience. In Proceedings of the 11 th Annual Usability Professionals' Association Conference, UPA 2002 (pp. 51) UPA. 13. Chattratichart, J. Brodie, 1. (2002b) Extending the heuristic evaluation method through contextualisation. In Proceedings of the 46th Annual Meeting of the Human Factors and Ergonomics Society, HFES 2002 (pp. 641 645) HFES. [This paper was nominated for the Alphonse Chapani' s Best Student Paper A ward at HFES 2002. 14. Chattratichart,1. Kuljis, 1. (2002) Exploring the effect of control flow and traversal direction on VPL usability for novices. Journal of Visual Languages Computing, 13(5) London: Academic Press, 471 500. 15. Chattratichart, J. Kuljis, J. (2001a) Some evidence for graphical readership, paradigm preference, and the match mismatch conjecture in graphical programs. In G. Kadoda (Ed. Proceedings of the 13 Annual Meeting of the Psychology of Programming Interest Group, PPIG 2001 (pp. 173 189) Sheffield: Print Unit. 16. Chattratichart, J. Kuljis, 1. (2001b) Why diagrams are sometimes difficult. In H. Michitaka (Ed. Proceedings of the Eighth IFIP TC13 Conference on HumanComputer Interaction, Interact 2001, Volume 2 (pp.755 756) 17. Chattratichart, J. (2000) Visualisation of program specification. In S. Turner and P. Turner (Eds. Proceedings of Human Computer Interaction, HCI 2000 (Vol.2, pp. 145 146) 18. Chattratichart, J. Kuljis, 1. (20", "author_names": [ "Jarinee Chattratichart" ], "corpus_id": 19759830, "doc_id": "19759830", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Usability issues and design principles for visual programming languages", "venue": "", "year": 2003 }, { "abstract": "s The Journal of Pain S75 characterized her pain as burning, shooting, and sharp and quantified it as 10/10 in severity. She noted significant deficits in sleep quality with decreased ability to perform ADLs, and overall functioning due to disabling pain causing her to be homebound. Physical exam was significant for allodynia of the right C4 C5 dermatomes. The patient failed multiple neuropathic medications due to poor efficacy and sedation including: amitriptyline, pregabalin, duloxetine, and gabapentin. The patient tried nighttime acetaminophen oxycodone, but did not report any improvement in her pain level or function. To aidwith themanagement of the radicular component of her pain a cervical intralaminar epidural steroid injection was performed, however, it failed to produce durable pain control. Given the neuropathic component, underlying pathology of the pain, and the patient's poor success with conservative measures the patient was considered for spinal cord stimulator trial. The trial was completed using an eight contact lead inserted into the T5 6 intralaminar space. The leadwas then advanced along the epidural space and lateralized over the exiting nerve roots in the final position at the top of C2. At completion, the lead covered the right nerve roots of C2 C5. At follow up, the patient reported greater than 75% pain control. She reported improvements in ADL's with no functional limitations secondary to pain. The patient was scheduled for definitive implant of the device. Pain related to schwannoma resection is an uncommon clinical occurrence. A trial of nerve root stimulation can be attempted in patients who are refractory to non invasive treatments. This case demonstrates that single lead stimulation of the pain generating nerve roots can produce significant relief in patients who are status post schwannoma resection. F10 Neuropathic Pain: Pharmacological Treatment (401) Brain alpha 7 nicotinic acetylcholine receptor positive allosteric modulator attenuates mechanical allodynia and hyperalgesia in a mouse model of neuroinflammatory pain M Abbas and S Rahman; Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD Neuroinflammatory pain is a chronic neurological disorder characterized by allodynia and hyperalgesia. Previous studies have shown that microglial alpha 7 nicotinic acetylcholine receptor (a7 nAChRs) in the central nervous system is involved in pain production and maintenance involving nuclear factor kappa B (NF kB) The objective of the present study was to determine the effects of 3a,4,5,9bTetrahydro 4 (1 naphthalenyl) 3H cyclopentan[c]quinoline 8 sulfonamide (TQS) an alpha7 nAChR positive allosteric modulator, and telmisartan (Tel) an NF kB antagonist, on lipopolysaccharide (LPS)induced neuroinflammatory pain using von Frey hair test, a widely used method for quantification of mechanical allodynia and hot plate test, a commonly used technique for hyperalgesia assessment in mice. In addition, we examined the effects of TQS (1 or 4 mg/kg) on mRNA for inhibitor of kappa B (IkB) an NF kB inhibitory protein. Acute administration of LPS (1 mg/kg, i.p. increased (p<0.05) the sensitivity to pain (allodynia and hyperalgesia) after 6 hours. TQS (0.25, 1 or 4 mg/kg, i.p. decreased LPS induced allodynic or hyperalgesic response (p<0.05) Pretreatment of Tel (1 mg/kg, i.p. with TQS (0.25 mg/kg, i.p. reduced LPS induced allodynia and hyperalgesia. TQS (4 mg/kg, i.p. also reduced the expression of IkB mRNA in the hippocampus suggesting the involvement of NF kB. Taken together, these results suggest that TQS decreases LPS induced neuroinflammatory pain by reducing hippocampal NF kB activation. (402) A retrospective investigation into the impact of early post operative intravenous ketamine infusion on recovery and phantom limb pain in new amputees K Jaremko and E Viscusi; Thomas Jefferson University, Philadelphia, PA NMDA receptor antagonists, such as ketamine, have been purported to minimize central sensitization at the spinal cord level and may decrease ongoing neuropathic pain following acute neuronal injury. There is conflicting information in the literature regarding the efficacy of intravenous ketamine infusions to treat acute postamputation pain and potentially ameliorate chronic phantom limb pain. This retrospective observational study tests the hypothesis that intravenous ketamine infusions initiated within 30 days of limb amputation will improve phantom pain sensations, pain at discharge, decrease concurrent opioid usage, and contribute to better outcomes without significant adverse effects. All patients that underwent limb amputation and received a consult to the Acute Pain Medicine Service (APMS) for ketamine treatment during hospitalization from January 2009 through October 2015 are eligible for study inclusion. IRB approved data collection includes APMS documentation of pain characterization and intensity over time, pain at discharge, duration and dosage of ketamine, adjuvant analgesic usage, co morbidities, and psychoactive, hepatic, or cardiovascular side effect occurrences. Data collection is ongoing and currently inconclusive, however there is a trend towards decreased neuropathic pain and phantom sensations at doses with a minimal side effect profile. The patient population referred to APMS is likely biased by greater uncontrolled pain, potentially in conjunction with more complex comorbidities limiting medication management. Therapeutic significance in this challenging population suggests beneficial application to a broader spectrum of patients undergoing amputation. In conclusion, our preliminary findings on the safety and efficacy of ketamine infusion for phantom pain during the initial post amputation hospitalizationwarrants further prospective research to investigate its potential role in acute pain management protocols. (403) Co administration ofmirogabalin and zolpidem in healthy subjects: results from a randomized, double blind, drug drug interaction study M Jansen, D Merante, A Currie, M Velinova, K Brown, and H Zahir; Daiichi Sankyo Pharma Development, Edison, NJ Mirogabalin, a preferentially selective a2d 1 ligand, is intended for treatment of pain associated with fibromyalgia and neuropathic pain. A four treatment (placebo (PBO)/PBO; mirogabalin 10mg /PBO; PBO/zolpidem 10mg; mirogabalin 10mg /zolpidem 10mg, 4 period, crossover study was conducted in 20 healthy subjects to evaluate the acute interaction potential between mirogabalin and a single dose of zolpidem. Washout periods were =7 days. Serial blood samples were collected for measurement of mirogabalin and zolpidem pharmacokinetic parameters (Cmax, tmax, AUCtau [mirogabalin] AUC0 inf [zolpidem] and t1/2) Pharmacodynamic assessments included body sway, digit symbol substitution test (DSST) visual analog scale of mood and alertness, vertigo symptom scale, and brief ataxia rating scale. Safety and tolerability were also assessed. Study subjects were randomized and completed all 4 treatment periods. Mirogabalin pharmacokinetic values were similar when co administered with PBO or zolpidem; zolpidem had similar pharmacokinetic values when co administered with PBO or mirogabalin. Mirogabalin alone did not appear to affect pharmacodynamic assessments compared with PBO. Zolpidem alone increased body sway and decreasedDSSTand self rated alertness. Co administration withmirogabalin did not affect themagnitude or time course of the zolpidem effects. The most common adverse events were dizziness, headache, and somnolence. Dizziness was reported by most (75% 80% subjects after zolpidem treatment; incidence and severity were not affected by mirogabalin co administration. A numerically greater than additive increase in somnolence frequency (but not severity) was noted with mirogabalin/zolpidem co administration. There were no apparent treatment related trends in laboratory test results or vital signs. In summary, mirogabalin/zolpidem coadministration caused no clinically relevant pharmacokinetic interactions. Zolpidem alone increased body sway and decreased DSST and self rated alertness; these effects did not appear to be influenced by mirogabalin co administration. Mirogabalin/zolpidem co administration increased the frequency of somnolence. Overall, mirogabalin/zolpidem co administration was considered safe in this study. Supported by Daiichi Sankyo, Inc. (404) Healthcare utilization in patients with postherpetic neuralgia J Gilbert, T Goss, K Patel, and J Gudin; Boston Healthcare Associates,", "author_names": [ "Kellie Jaremko", "Eugene R Viscusi" ], "corpus_id": 26277388, "doc_id": "26277388", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "(402) A retrospective investigation into the impact of early post operative intravenous ketamine infusion on recovery and phantom limb pain in new amputees.", "venue": "The journal of pain official journal of the American Pain Society", "year": 2016 }, { "abstract": "s The Journal of Pain S75 characterized her pain as burning, shooting, and sharp and quantified it as 10/10 in severity. She noted significant deficits in sleep quality with decreased ability to perform ADLs, and overall functioning due to disabling pain causing her to be homebound. Physical exam was significant for allodynia of the right C4 C5 dermatomes. The patient failed multiple neuropathic medications due to poor efficacy and sedation including: amitriptyline, pregabalin, duloxetine, and gabapentin. The patient tried nighttime acetaminophen oxycodone, but did not report any improvement in her pain level or function. To aidwith themanagement of the radicular component of her pain a cervical intralaminar epidural steroid injection was performed, however, it failed to produce durable pain control. Given the neuropathic component, underlying pathology of the pain, and the patient's poor success with conservative measures the patient was considered for spinal cord stimulator trial. The trial was completed using an eight contact lead inserted into the T5 6 intralaminar space. The leadwas then advanced along the epidural space and lateralized over the exiting nerve roots in the final position at the top of C2. At completion, the lead covered the right nerve roots of C2 C5. At follow up, the patient reported greater than 75% pain control. She reported improvements in ADL's with no functional limitations secondary to pain. The patient was scheduled for definitive implant of the device. Pain related to schwannoma resection is an uncommon clinical occurrence. A trial of nerve root stimulation can be attempted in patients who are refractory to non invasive treatments. This case demonstrates that single lead stimulation of the pain generating nerve roots can produce significant relief in patients who are status post schwannoma resection. F10 Neuropathic Pain: Pharmacological Treatment (401) Brain alpha 7 nicotinic acetylcholine receptor positive allosteric modulator attenuates mechanical allodynia and hyperalgesia in a mouse model of neuroinflammatory pain M Abbas and S Rahman; Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD Neuroinflammatory pain is a chronic neurological disorder characterized by allodynia and hyperalgesia. Previous studies have shown that microglial alpha 7 nicotinic acetylcholine receptor (a7 nAChRs) in the central nervous system is involved in pain production and maintenance involving nuclear factor kappa B (NF kB) The objective of the present study was to determine the effects of 3a,4,5,9bTetrahydro 4 (1 naphthalenyl) 3H cyclopentan[c]quinoline 8 sulfonamide (TQS) an alpha7 nAChR positive allosteric modulator, and telmisartan (Tel) an NF kB antagonist, on lipopolysaccharide (LPS)induced neuroinflammatory pain using von Frey hair test, a widely used method for quantification of mechanical allodynia and hot plate test, a commonly used technique for hyperalgesia assessment in mice. In addition, we examined the effects of TQS (1 or 4 mg/kg) on mRNA for inhibitor of kappa B (IkB) an NF kB inhibitory protein. Acute administration of LPS (1 mg/kg, i.p. increased (p<0.05) the sensitivity to pain (allodynia and hyperalgesia) after 6 hours. TQS (0.25, 1 or 4 mg/kg, i.p. decreased LPS induced allodynic or hyperalgesic response (p<0.05) Pretreatment of Tel (1 mg/kg, i.p. with TQS (0.25 mg/kg, i.p. reduced LPS induced allodynia and hyperalgesia. TQS (4 mg/kg, i.p. also reduced the expression of IkB mRNA in the hippocampus suggesting the involvement of NF kB. Taken together, these results suggest that TQS decreases LPS induced neuroinflammatory pain by reducing hippocampal NF kB activation. (402) A retrospective investigation into the impact of early post operative intravenous ketamine infusion on recovery and phantom limb pain in new amputees K Jaremko and E Viscusi; Thomas Jefferson University, Philadelphia, PA NMDA receptor antagonists, such as ketamine, have been purported to minimize central sensitization at the spinal cord level and may decrease ongoing neuropathic pain following acute neuronal injury. There is conflicting information in the literature regarding the efficacy of intravenous ketamine infusions to treat acute postamputation pain and potentially ameliorate chronic phantom limb pain. This retrospective observational study tests the hypothesis that intravenous ketamine infusions initiated within 30 days of limb amputation will improve phantom pain sensations, pain at discharge, decrease concurrent opioid usage, and contribute to better outcomes without significant adverse effects. All patients that underwent limb amputation and received a consult to the Acute Pain Medicine Service (APMS) for ketamine treatment during hospitalization from January 2009 through October 2015 are eligible for study inclusion. IRB approved data collection includes APMS documentation of pain characterization and intensity over time, pain at discharge, duration and dosage of ketamine, adjuvant analgesic usage, co morbidities, and psychoactive, hepatic, or cardiovascular side effect occurrences. Data collection is ongoing and currently inconclusive, however there is a trend towards decreased neuropathic pain and phantom sensations at doses with a minimal side effect profile. The patient population referred to APMS is likely biased by greater uncontrolled pain, potentially in conjunction with more complex comorbidities limiting medication management. Therapeutic significance in this challenging population suggests beneficial application to a broader spectrum of patients undergoing amputation. In conclusion, our preliminary findings on the safety and efficacy of ketamine infusion for phantom pain during the initial post amputation hospitalizationwarrants further prospective research to investigate its potential role in acute pain management protocols. (403) Co administration ofmirogabalin and zolpidem in healthy subjects: results from a randomized, double blind, drug drug interaction study M Jansen, D Merante, A Currie, M Velinova, K Brown, and H Zahir; Daiichi Sankyo Pharma Development, Edison, NJ Mirogabalin, a preferentially selective a2d 1 ligand, is intended for treatment of pain associated with fibromyalgia and neuropathic pain. A four treatment (placebo (PBO)/PBO; mirogabalin 10mg /PBO; PBO/zolpidem 10mg; mirogabalin 10mg /zolpidem 10mg, 4 period, crossover study was conducted in 20 healthy subjects to evaluate the acute interaction potential between mirogabalin and a single dose of zolpidem. Washout periods were =7 days. Serial blood samples were collected for measurement of mirogabalin and zolpidem pharmacokinetic parameters (Cmax, tmax, AUCtau [mirogabalin] AUC0 inf [zolpidem] and t1/2) Pharmacodynamic assessments included body sway, digit symbol substitution test (DSST) visual analog scale of mood and alertness, vertigo symptom scale, and brief ataxia rating scale. Safety and tolerability were also assessed. Study subjects were randomized and completed all 4 treatment periods. Mirogabalin pharmacokinetic values were similar when co administered with PBO or zolpidem; zolpidem had similar pharmacokinetic values when co administered with PBO or mirogabalin. Mirogabalin alone did not appear to affect pharmacodynamic assessments compared with PBO. Zolpidem alone increased body sway and decreasedDSSTand self rated alertness. Co administration withmirogabalin did not affect themagnitude or time course of the zolpidem effects. The most common adverse events were dizziness, headache, and somnolence. Dizziness was reported by most (75% 80% subjects after zolpidem treatment; incidence and severity were not affected by mirogabalin co administration. A numerically greater than additive increase in somnolence frequency (but not severity) was noted with mirogabalin/zolpidem co administration. There were no apparent treatment related trends in laboratory test results or vital signs. In summary, mirogabalin/zolpidem coadministration caused no clinically relevant pharmacokinetic interactions. Zolpidem alone increased body sway and decreased DSST and self rated alertness; these effects did not appear to be influenced by mirogabalin co administration. Mirogabalin/zolpidem co administration increased the frequency of somnolence. Overall, mirogabalin/zolpidem co administration was considered safe in this study. Supported by Daiichi Sankyo, Inc. (404) Healthcare utilization in patients with postherpetic neuralgia J Gilbert, T Goss, K Patel, and J Gudin; Boston Healthcare Associates,", "author_names": [ "Muzaffar Abbas", "Shafiqur Rahman" ], "corpus_id": 34139082, "doc_id": "34139082", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "(401) Brain alpha 7 nicotinic acetylcholine receptor positive allosteric modulator attenuates mechanical allodynia and hyperalgesia in a mouse model of neuroinflammatory pain.", "venue": "The journal of pain official journal of the American Pain Society", "year": 2016 }, { "abstract": "Today the world is going through a rapid change. Globalizations made possible revolutionary changes or development in information and communications technology. In modern age, we can't think to live without information and technology. Today, computers are considered one of the important things a person establishment can utilize. Many people have begun to depend on resources like information and technology to get things properly working on their behalf. The process of sharing the data has become a lot easier. despite the physical distance that may possibly be in between or for those who are not familiar with the function of the business that are involved in the information technology sector. In the field of engineering concentration is mainly on the use of telecommunication and computers to retrieve, store and then transmit data and information, making it a major player in the computer world. Information and technology is actually an area where innovations are managed. Technology is making the multifunctional functions to be available in a single device. Thus, we can have multifunctional usage of the single device we own. The simpler the work gets with and the more we get dependent on it. Technology makes us lethargic with little or no physical activity, in one aspect; but the same and provides a creative jobs including physical activity. Example; games like V games which are challenging video games. And at the same time, time recreational helping to spend time in a joyful way. Today, we don't find even a simple young kid without using the available and tot him /her. Technology makes us dependent on it and we can't expect or imagine a life without using the word 'technology' in it. Hence, technology plays a major role in our lives. Information and technology has a great significance in the field of communication, inventory management, data management, management informative system, education and health sectors etc. Information and Technology plays a crucial role in every sphere of life. Modern Information and Technology has become so entrenched in the idea of a modern society that both are closely intertwined with each other. Developing countries try to get better utilities, more vehicles, faster computers as well as internet and cell phone providers because that's what makes a society modern. Modern Technology must be implemented in order to accomplish the feats required of a modern society. Information and technology makes our age more transformative, transmitter and dominion. Our society could be imagined without new technology and their role both in society and in human life. Information technologies are tools and techniques that support and development of information system. A definition by American association, the study, design, development, implementation support or management of computers based information systems, particularly software, applications and computer hardware.'1 Information and Technology become an important part of every business plan. From the multi national companies who maintain mainframe system and databases to small business that own a single computer. The reason for the daily use of computer technology in business can best be determined by looking at how it is being used across the business world .technology is building bridges between people on opposite sides of the globe, bringing people from all cultures and background into contact with each other. Modern age is totally different from the previous one. Our society could not be imagined without new technology and their role both in the society and in human life. Modern technology has revolutionized people's communication. COMMUNICATION: for many companies, e mail is the main means of communication between employees, suppliers and customers. E mail was one of the early drivers of the internet providing a simple and inexpensive means to communicate. Over the years, a number of other communication tools have also evolved, allowing staff to communicate using live chat system online meeting tools and video conferencing. (c) 2018 JETIR January 2018, Volume 5, Issue 1 www.jetir.org (ISSN 2349 5162) JETIR1808660 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 141 System voice over internal protocol (VOIP) telephone and smart phones, offer even more high tech ways for employees to communicate. INVENTORY MANAGEMENT: when it comes to managing inventory, organizations, need to maintain enough stock to meet demand without investing in more than they require inventory management systems track the quantity of each item a company maintains triggering an order of additional stock when the qualities of each system a company maintains, triggering an order of additional stock when the quantities fall below a predetermined amount. These systems are best used when the inventory management system is connected to the point of sale (POS) system. The POS system ensures that each time ,an item is sold, one of those items is removed from the inventory count, creating a closed information loop between all departments. DATA MANAGEMENT: The days of large file rooms, rows of filing cabinets and the mailing of documents is fading fast. Today, most companies store digital versions of documents on servers and storage devices. These documents become instantly available to everyone in the company regardless of their geographical location. Companies are able to store and maintain a tremendous amount of historical data economically and employees benefit from immediate access to the documents they need. MANAGEMENT INFORMATION SYSTEMS: Storing data is only a benefit if that data can be used effectively. Progressive companies use that data as part of their strategic planning process as well as the tactical execution of that strategy. MIS (Management Information Systems) enable companies to track profitability over time, maximize return on investment and identity areas of improvement. Managers can track sales on a daily basis allowing them to immediately react to lower than expected number by boosting employee productivity or reducing the lost of an item. CONSUMER RELATIONSHIP MANAGEMENT: companies are using information and technology to improve the way they design and manage customer relationship. Customer relationship management (CRM) systems capture every interaction a company has with a customer. So that a more enriching experience is possible if a customer calls a call centre with an issue, the customer support representative will be able to see what the customer has purchased view shipping information, call up the training manual for that item and effectively respond to the issue. The entire interaction is stored in the CRM system, ready to be recalled if the customer has a better, more focused experience and the company benefits from improved productivity. We are living in a civilized society where Information and Technology plays an impressive role. every small work we do is technology dependent. Today, every other person is recognized with the device or gadget he carries which is technically advanced. Ultimately we can say that 'living without technology is like living without air in this technical world of today. Therefore we are much dependent on technology. EDUCATION; information and technology play a major role in the modern education. In the faster and technological developed world in traditional times, education was only in hand books but now it is more advanced and practical. Information and technology helps the students to make assignments and projects. Now days, in ordinary schools, the education is through a form named smart class. It provides help the students who are backward in their studies. The modern education system is not only hand book information but also it is a profession. Education is not only for achieving a profession but also to become a good personality. They depend more on Information and technology which may leads to them in wrong side. Some are promoted to do inventions. Many wonders of Information and technology such as Radio, television etc. is helpful for the students. Starting with the simple example of food storage, today the shelf life of food is reduced with the help of new machines and equipments. Thus, making the consumer to have a case at its consumption and also in saving a lot of productive time ultimately, making the person dependent on it for his own benefits. This is unlike to the times of traditional cooking where people had to spare time and even do physical labour compared to the technically advanced time of today. New technology sometimes is making people dull. For example if you have to add 85+54+98+549 for something difficult like that then you will surely depend on calculators of such devices. But where's our mind mechanism? So we need technologies because they are making our life more comfortable and safely but let's not make technologies our habit. 2 computers have become an indispensable part of modern life. Change is always better. We must discard the traditional and obsolete method of teaching. Gone are the days of slates and chalks. Teaching through computers will be more effective. In the western world, we see that they have already switched over to this new way of teaching and learning. The computer is not an alternative of teaching but it is an able helper of the teachers. Teachers can teach better through the computer because it is (c) 2018 JETIR January 2018, Volume 5, Issue 1 www.jetir.org (ISSN 2349 5162) JETIR1808660 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 142 an audio visual means of information. For example it is not an easy for all the buildings of the world nor is it possible to know about them through books. Here the computers will give them the best information. The internet is the gateway to each and every type of information. Technology had made our live simple but dependent on it. We can sit in a corner and get connect", "author_names": [ "Hitesh Chander Monga" ], "corpus_id": 187099156, "doc_id": "187099156", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ROLE OF INFORMATION AND TECHNOLOGY IN MODERN TIMES", "venue": "", "year": 2018 }, { "abstract": "Image Processing established itself as one of the most contemporary research areas because of its wide variety of application requirements. Complexity in Colour image processing motivated the researchers to use Colour to Greyscale conversion as the preliminary step for any Image processing applications. All the new proposals on Color to Greyscale conversion are more expensive and hence we considered fundamental methods for this analytical survey. Majority of the researchers use a common fundamental method of averaging RGB channels which is not preferable for all applications. This paper shows that results of the Image Processing application are influenced by selection of Colour to Greyscale conversion method. We mainly focused to compare these conversion methods based on primary Image Processing techniques: Edge detection and Segmentation along with Colour perception. Main objective of this paper is to produce fruitful results that will help in selection of application specific Colour to Greyscale conversion method to experience good results with low computational speed. Keywords Colour to Greyscale conversion method, Image Processing techniques, Colour Perception, Edge detection, Segmentation, Analytical survey I. IMAGE PROCESSING TECHNIQUES AT GLANCE Digital Image[1] will be the heart of many real time applications in the world of multimedia. In general, Image Processing[1] refers to set of operations or techniques that can be performed on two dimensional picture by the computer algorithms to produce various types of outputs based on the requirements of the user. With in the span of few years, Image Processing is flooded with number of processing techniques. Most of these techniques produce image as output by embedding some effects or changes on the given image and few of them produces some features or information as output. Most promising categories includes Image representation, Image Compression, Image Enhancement, Image Analysis and Image Understanding. A. Image Representation Representation is the primitive step in digitization of captured image from cameras. Roots of digital image representation is started around 1870's with digitization of black and white image. Later 1960's became a mile stone by the colour image representation with three co ordinate system known as Colour model like RGB. Even though RGB is the fundamental for representation of pixels, many of the real time application requirements provoked for other representations like CMY, YUV and HSV etc. Che YenWen[3] presented the details of mostly used Colour models along with equations used for representation and transformation. RGB[2,3] is an additive model which uses Red, Green and Blue colours to represent each pixel and is preferable in display units. Similarly CMY[2,3] is subtractive colour model which uses Cyan, Magenta and Yellow colours to represent each pixel and is prescribed in printing devices. Summary of primary colour models are listed in Table 1 along with components used for representation and usage of colour model. Table 1: Information of Color Models Color Model Color Components Primary usage RGB Red, Green, Blue Used for display devices because it describes what kind of light need to be emitted to produce given color CMY CMYK Cyan, Magenta, Yellow Used in printing process because it describes what kind of inks need to apply so the light reflected from substrate and through inks produces given color CIE XYZ/RGB X, Y, Z Used for display devices with gamma correction which is based on the measurements of human color perception CIE LAB/LUV L, U, V Used for surface colors and It is more perceptually linear than other color models HSV /HSL Hue, Saturation, Value/Lightness Used by artists because it is often more natural to think about color in terms of hue and saturation, it is transformation of RGB color model YUV Luminance(Y) Used as analog video representation for PAL television broadcasting Venkateswarlu, International Journal of Advanced Research in Computer Science and Software Engineering 4(10) October 2014, pp. 335 345 (c) 2014, IJARCSSE All Rights Reserved Page 336 Chrominance (U, V) YIQ Luminance(Y) Chrominance (I, Q) Used as analog video representation for NTSC television broadcasting YCbCr Luminance(Y) Chrominance (Cb, Cr) Used widely in digital video and image compression schemes like MPEG, JPEG B. Image compression Technical advancements in the field of multimedia caused to use larger resolution images which costs more in terms of memory. In case of networked multimedia applications like broadcast TV, remote sensing via satellites, military communication via aircraft, radar and teleconferencing large amount of image data need to be transferred over network which increases bandwidth. This bottleneck of bandwidth can be reduce by minimizing the number of bits required to represent an image. These applications increases the need of compression techniques for the image and video data. There are several image compression techniques which are broadly classified as Lossless and Lossy techniques. Details of these techniques are out of the scope to this paper and hence not considered for the discussion. C. Image Enhancement Image enhancement is to process an image so that result is more suitable than original image for specific application. Photo editing is the most important economical task in this digital world which involves process of adjusting digital images so that the results are more suitable for display or further image analysis. It refers to sharpening of image features such as increasing quality, brightness and contrast to make more attractive image production. Raman Maini[4] classified enhancement methods into Spatial Domain and Frequency Domain and focused mainly on various transformations based, histogram based methods. Similarly, Matlab programming aspects of image processing can be found from Chris Solomon[5] Here generalized set of Image Enhancement techniques are discussed. Noise Reduction: Image noise is random variation of brightness or colour information in image that is included due to environment and camera sensors. Gaussian noise and Salt and Pepper noise are most occurring noise in the images. It is impossible to eliminate noise completely, but noise can be suppressed using filters like Linear smoothing, Median. Changing Sharpness or Brightness of image: Lightness or Darkness of image pixel can be referred as Brightness of image where as Sharpness is defined as edge contrast. If brightness increases, lighting effect in the image increases. Similarly, if Sharpness increases smoothness of edges increases. Histogram equalization: It is a method of adjusting contrast of image which usually increases global contrast that allows for areas of lower local contrast to gain higher contrast. This can be accomplished by effectively spreading out most frequent intensity values. De blurring: Image blur is difficult to avoid in many situations and can often ruin a photograph. Image blur causes decrease of quality in the image and left with unclear images. Smoothing filters are generally used for de blurring images. D. Image Analysis Image analysis[6, 7] is the extraction of meaningful information from images by means of digital image processing techniques. Image processing research requires more sophisticated techniques in order to measure the characteristics of the Region of Interest or Objects on the given image. This induced for novel techniques to extract measurements of the objects for the analysis of image. Useful methods for image analysis and their evaluation can be obtained from PunamThakare[6] Edge Detection(ED) It is the process of identifying points in digital image at which image brightness changes sharply or more formally has discontinuities. The points at which image brightness changes sharply are typically known as Edges. Typical edge might for instance be border between block of two regions. Canny edge detector is one of the mostly used edge detection methods. Segmentation or Pixel Classification(SEG) It is the process of partitioning digital image into multiple segments. More precisely, image segmentation is the process of assigning label to every pixel in an image such that pixels with same label share certain visual characteristics. Thresholding, Clustering, Region growing methods are some of the segmentation techniques. E. Image Understanding Image understanding[7] is the process of actually interpreting those regions or objects to figure out what is actually happening in the image. Advanced Computer Vision applications motivated the researchers to inculcate several operations that are mainly focusing the concept of understanding images by extracting high level features of the objects. Image analysis techniques can be considered as primitive tools for various image understanding operations. Most common techniques of them are given below. Optical Character Recognition(OCR) It is the process of converting images of written or printed text into computer readable text. It is widely used as form of data entry from some sort of original paper data source like passport documents, invoices, bank statements etc. Venkateswarlu, International Journal of Advanced Research in Computer Science and Software Engineering 4(10) October 2014, pp. 335 345 (c) 2014, IJARCSSE All Rights Reserved Page 337 Feature Extraction or Pattern Recognition(PR) It involves simplifying amount of resources required to describe large set of data accurately. When performing analysis of complex data one of major problems stem from number of variables involved. Best results are achieved when an expert constructs a set of application dependent features. Thresholding, Template matching techniques are used for feature extraction. Object Recognition(OR) It is the task of finding and identifying objects in image. Objects can even be recognized when they are partially obstructed from view. Approaches used", "author_names": [ "Isunuri Bala Venkateswarlu" ], "corpus_id": 212490502, "doc_id": "212490502", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Analytical Survey of Colour to Greyscale Conversion Methods Based on Primary Image Processing Techniques", "venue": "", "year": 2014 }, { "abstract": "Image Edge detection significantly reduces the amount of data and filters out useless information, while preserving the important structural properties in an image. Since edge detection is in the forefront of image processing for object detection. Remote sensing images are generally corrupted from noise. Mathematical morphology is a good technique for edge detection for noisy image. In this paper two types (flat and concave) structuring element of different size is implemented on different remote sensing images. The noise can be suppressed by mathematical morphology. So by using mathematical morphology the image can be enhanced and the edges can be detected. In this paper, the result of edge detection using mathematical morphology will be compared with traditional edge detectors (Sobel, Prewitt Laplacian of Gaussian (LOG) and Canny edge detector) The software is developed using MATLAB 7.0 .Objective methods are used to evaluate adopted method and other the different edge operators It proved that the morphological filter is more important process in the edge detection for noisy image. 1Introduction Edge detection has been increasing popular for its usage in most image processing applications. Edge detection refers to the process of identifying and locating sharp discontinuities in an image. The discontinuities are abrupt changes in pixel intensity which characterize boundaries of objects in a scene. An edge detection filter can be used to improve the appearance of blurred images or video streams.[Mahmoud Marshall 2008] Classical methods of edge detection involve convolving the image with an operator (a 2 D filter) which is constructed to be sensitive to large gradients in the image while returning values of zero in uniform regions. There are an extremely large number of edge detection operators available, each designed to be sensitive to certain types of edges.[Mahmoud Marshall 2008, Raman] Remote sensing images are generally corrupted from noise .Edge detection is difficult in noisy images, since both the noise and the edges contain high frequency content. Attempts to reduce the noise result in blurred and distorted edges. Operators used on noisy images are typically larger in scope, so they can average enough data to discount localized noisy pixels [Kaur Et Al 2010] In this work ,we will introduce a new approach to edge detection by morphological filter. 2Edge detection operators: Edge detection operators are often implemented with convolution masks and discrete approximations to differential operators. These operators may return magnitude and direction information, some return magnitude only. Potential edge points are found by examining the relationship a pixel has with its neighbors; an edge implies a change in gray level. There are many techniques for edge detection as under: see [Roushdy 2006, Kaur et al. 2010, Kaur et al. 2011] 1. Sobel operator 2. Canny edge detection 3. Prewitt operator 4. Laplacian of Gaussian 5. Roberts edge detection Sobel operator is based on convolving the image with a small, separable, and integer valued filter in horizontal and vertical and is therefore relatively inexpensive in terms of computations. British Journal of Science 149 February 2012, Vol. 3 (2) (c) 2011 British Journals ISSN 2047 3745 Canny edge detection operator was developed by John F. Canny in 1986 and uses a multistage algorithm to detect a wide range of edges in images. Prewitt operator edge detection masks are the one of the oldest and best understood methods of detecting edges in images. Basically, there are two masks, one for detecting image derivatives in X and one for detecting image derivative in Y. To find edges, a user convolves an image with both masks, producing two derivative images (dx and dy) The strength of the edge at given location is then the square root of the sum of the squares of these two derivatives. Laplacian of Gaussian (LOG) combined Gaussian filtering with the Laplacian .Using Convolution of Gaussian operator with image, the image is smoothed, then the edge is detected using Laplacian operator(second derivative) Roberts edge detection method is one of the oldest method and is used frequently in hardware implementations where simplicity and speed are dominant factors [Kaur et al. 2010] 3Mathematical morphological operators Morphology relates to structure or form of objects. Morphological filtering simplified segmented images by smoothing out object outlines using filling small holes, eliminating small projections. Primary operations are dilation and erosion. These operations use a structuring element which determines exactly how object will be dilated or eroded. A structuring element is a special mask filter that enhances input images .It can be of different sizes and of different shapes (square, diamond, and circle) This paper will focus on two types of structuring element. First, flat structuring elements, in this case, structuring element could be [1, 1, 1] Second, concave structuring elements, in this case, structuring element could be [0, 1, 0] In this paper, it will be demonstrated that these two structuring elements. Following are the main mathematical morphological operators: [Kaur et al. 2010, Kaur Mohal et al. 2011] 1. Dilation 2. Erosion 3. Opening 4. Closing Dilation Dilation is defined as the maximum value in the window. Hence the image after dilation will be brighter or increased in intensity. It also expands the image and mainly used to fill the spaces. Dilation process expanding image objects by changing pixels with value of \"0\" to \"1\" Erosion Erosion is just opposite to dilation. It is defined as the minimum value in the window .The image after dilation will be darker than the original image .It shrinks or thins the image. Erosion process shrinking objects or images by changing pixels with a value of ,1\" to \"0\" Opening and closing Both parameters are formed by using dilation and erosion. In opening, firstly image will be eroded and then it will be followed by dilation. And in case of closing, firstly image will be dilated and then followed by erosion [Kaur Mohal et al. 2011] 4 Edge detection and enhancement by Morphological filter Morphological edge detection algorithm selects appropriate structuring element of the processed image makes use of the basic theory of morphology including erosion, dilation, opening and closing operation and synthesization operations of them get clear image edge. The effect of erosion and dilation (difference between dilation and erosion) operations is better for image edge, but they are worse for noise filtering. As opposed to erosion and dilation, opening and closing operations are better for filtering [Roushdy 2006, Maragos 2004] British Journal of Science 150 February 2012, Vol. 3 (2) (c) 2011 British Journals ISSN 2047 3745 5 Proposed algorithm: 1) Read the noisy image. 2) Apply the different structuring elements (3*3 concave or flat) 3) The morphological filter is applied for a noisy image to get a clear image before edge detection of noisy image. Opening closing operation is firstly used as preprocessing to filter noise. 4) Edges can be detected by taking the difference between the dilated and eroded image. 5) Increase the intensity of the image as per requirement. 6) Compare the result (using RMSE, PSNR) with the traditional techniques for noisy image before and after applying morphological filter. 6 Results: The morphological filter is applied for a noisy image to get a clear image before edge detection of noisy image. Opening closing operation is firstly used as preprocessing to filter noise. The perfect image edge will be got by performing the difference between the dilation and erosion images. The visual comparison of the resultant images can lead us to the subjective evaluation of the performances of selected edge detectors. Figures (1&3) show the comparison between edge detection operators with salt and pepper noise without morphological filter. Figures (2&4) show the comparison between operators after morphological filter on the noisy image with salt and pepper. Objective methods are used in this experiment by calculating peak signal to noise ratio and the root mean square error between the edge detection images and the original image. Table (1) shows the peak signal to noise ratio and the root mean square error for different operators on noisy image before and after morphological filter is used. Operator Before After PSNR RMSE PSNR RMSE Image(1) Sobel 49.9 0.66 50.11 0.632 Canny 49.8 0.666 50.161 0.626 Prewitt 49.89 0.665 50.109 0.634 Robert 49.92 0.6617 50.01 0.648 LOG 49.96 0.656 50.30 0.606 Morphological Filter 50.05 0.641 52.23 0.388 Image(2) Sobel 48.392 0.941 48.786 0.859 Canny 48.398 0.940 48.900 0.837 Prewitt 48.399 0.940 48.788 0.859 Robert 48.408 0.938 48.592 0.899 LOG 48.457 0.927 49.156 0.789 Morphological Filter 48.471 0.924 50.339 0.602 Table (1) shows PSNR RMSE before and after Morphological filter. British Journal of Science 151 February 2012, Vol. 3 (2) (c) 2011 British Journals ISSN 2047 3745 7 Conclusion: In this work, edge detection is performed using mathematical morphology of remote sensing images. And different methods has been studied and compared. it concludes that ,after morphological filter the peak signal to noise ratio increases for all edge detector operators while the root mean square error decreases. Also, it concludes that the morphological filter is more important as an initial process in the edge detection for noisy image. The comparison shows that the root mean square error(RMSE) values of mathematical morphology is less and high in traditional methods .and also the Peak Signal to Noise Ration is high in case of mathematical morphology edge detection techniques as compared to traditional methods. The main advantages of mathematical morphology are direct geometric interpretation, simplicity and efficiency in hardware implementation while Sobel, and Prewitt have ver", "author_names": [ "Nedhal Mohammed Al-Shereefi" ], "corpus_id": 208974227, "doc_id": "208974227", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Morphological Filter is an Active Tool for Edge Detection in Noisy Image", "venue": "", "year": 2012 } ]

[ { "abstract": "Ahardmask composition for forming a resist underlayer film, a process for producing a semiconductor integrated circuit device, and a semiconductor integrated circuit device, the hardmask composition including an organosilane polymer, and a stabilizer, the stabilizer including one of acetic anhy dride, methyl acetoacetate, propionic anhydride, ethyl 2ethylacetoacetate, butyric anhydride, ethyl 2 ethylacetoac etate, Valeric anhydride, 2 methylbutyric anhydride, nonanol, decanol, undecanol, dodecanol, propylene glycol propyl ether, propylene glycol ethyl ether, propylene glycol methyl ether, propylene glycol, phenyltrimethoxysilane, diphenyl hexamethoxydisiloxane, diphenylhexaethoxydisiloxane, dioctyltetramethyldisiloxane, hexamethyltrisiloxane, tetram ethyldisiloxane, decamethyltetrasiloxane, dodecamethylpen tasiloxane, hexamethyldisiloxane, and mixtures thereof.", "author_names": [ "Sang Kyun Kim" ], "corpus_id": 202587727, "doc_id": "202587727", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photoresist layer Silicon based hardmask layer Carbon based hardmask layer Substrate", "venue": "", "year": 2017 }, { "abstract": "Stochastic defects in the photoresist profile are one of the main yield limiters in EUV lithography patterning. These stochastic defects can be, for example, local resist loss, resist profile footing, or resist scumming. A subset of these defects is transferred through the hardmask open (HMO) patterning, leading ultimately to electrical opens and shorts. We use on wafer data and process recipes to inform a physical etch model of the HMO process. This model is tested and confirmed by comparison to additional on silicon data. The established model provides a visualization of the defect transfer through individual process steps and highlights critical patterning steps that may limit electrical yield. For example, a change in in situ deposition time is observed to be more sensitive than oxide open or planarization film open times both in the model and on wafer. This provides us the insight to focus tuning deposition step times to reduce defectivity and improve process performance. Furthermore, this model provides insight into the type of defects which are eliminated during specific patterning steps, and the type of defects which are persistent and ultimately lead to electrical opens and shorts. To characterize these defects, we plant intentional defects with varying dimensions and study which ones stay through the entire HMO process and which ones are eliminated. This insight helps better understand the HMO process, which may lead in the future to further process improvements.", "author_names": [ "Dominik Metzler", "Mohamed Oulmane", "Sagarika Mukesh", "Philip J Stopford", "Karthik Yogendra", "Lawrence S Melvin" ], "corpus_id": 216327230, "doc_id": "216327230", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Simulation of photoresist defect transfer through subsequent patterning processes", "venue": "Advanced Lithography", "year": 2020 }, { "abstract": "A thick spin on carbon hardmask (SOH) material is designed to overcome inherent problems of amorphous deposited carbon layer (ACL) and thick photoresist. For ACL in use of semiconductor production process, especially when film thickness from sub micrometer up to few micrometers is required, not only its inherent low transparency at long wavelength light often causes alignment problems with under layers, but also considerable variation of film thickness within a wafer can also cause patterning problems. To avoid these issues, a thick SOH is designed with monomers of high transparency and good solubility at the same time. In comparison with photoresist, the SOH has good etch resistance and high thermal stability, and it provides wide process window of decreased film thickness and increased thermal budget up to 400degC after processes such as high temperature deposition of SiON. In order to achieve high thickness along with uniform film, many solvent factors was considered such as solubility parameter, surface tension, vapor pressure, and others. By optimizing many solvent factors, we were able to develop a product with a good coating performance", "author_names": [ "Taeho Kim", "Young-Min Kim", "Sunmin Hwang", "Hyunsoo Lee", "Miyeon Han", "Sanghak Lim" ], "corpus_id": 125192023, "doc_id": "125192023", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Study on thick film spin on carbon hardmask", "venue": "Advanced Lithography", "year": 2017 }, { "abstract": "The present invention relates to a resist lower layer film as a hard mask composition. The present invention is an organic silane based polymer (A) And the resist lower layer film provides a hard mask composition that includes one or more stabilizing agent (B) Resist lower layer film as a hard mask composition of the present invention can transfer the fine pattern to the material layer to exhibit excellent storage stability and excellent hard mask properties. A hard mask, an organic silane based polymer, a stabilizer, the storage stability", "author_names": [ "" ], "corpus_id": 139976658, "doc_id": "139976658", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hardmask Composition Coated under Photoresist with Improved Storage Stability", "venue": "", "year": 2008 }, { "abstract": "Abstract The study of the effects of photoresist thickness and the use of PECVD deposited oxide hard mask layer during source/drain high dose ion implantation process in the fabrication of ion sensitive field effect transistor (ISFET) is presented. Implementation of the new optimized process for the source/drain implant mask together with the improved process module have been successful in improving the threshold voltage (Vt) of the ISFET device from negative to more than 0.3 V. Consistent high ISFET yields of more than 90% were possible to achieve.", "author_names": [ "Nurhidaya Soriadi", "Azlina Mohd Zain", "Sharaifah Kamariah Wan Sabli", "Mohd Rofei Mat Hussin", "Hing Wah Lee" ], "corpus_id": 114654785, "doc_id": "114654785", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Study of Oxide Hardmask Effect on High Dose Implant Process for ISFET Fabrication", "venue": "", "year": 2017 }, { "abstract": "A hardmask composition for an under photoresist layer is provided to ensure excellent reproducibility of pattern and storage stability, good adhesion with a resist, and excellent solvent resistance for a developer used after exposing the resist, and to reduce film reduction in plasma etching. A hardmask composition for an under photoresist layer comprises an organic silane based polymer generated from a compound represented by the chemical formula 1; at least one selected from the group consisting of pyridinium p toluenesulfonate, amidosulfobetain 16, camphor 10 sulfonic acid ammonium salt, ammonium formate, triethylammonium formate, trimethyammonium formate, tetramethylammonium formate, pyridinium formate, tetrabutylammonium acetate, tetrabutylammonium azide, tetrabutylammonium benzoate, tetrabutylammonium bisulfate, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium cyanide, tetrabutylammonium fluoride, tetrabutylammonium iodide, tetrabutylammonium sulfate, tetrabutylammonium nitrate, tetrabutylammonium nitrite, tetrabutylammonium p toluenesulfonate and tetrabutylammonium phosphate; and solvent. In chemical formula 1, Rw, Rx, Ry and Rz are independently H or C1 5 alkyl; and n is an integer of 4 20.", "author_names": [ "" ], "corpus_id": 103460156, "doc_id": "103460156", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hardmask composition for under photoresist layer; method of manufacturing semiconductor ic device therewith; and semiconductor ic device produced thereby", "venue": "", "year": 2007 }, { "abstract": "A hard mask composition for a photoresist under layer, and a method for preparing a semiconductor integrated circuit device by using the composition are provided to improve film characteristics and storage stability and to enhance the solvent resistance against a resist developer. A hard mask composition for a photoresist under layer comprises a silane condensate which is a condensation polymer of the hydrolyzate formed from at least one compound represented by the formula 1; an ammonium salt; and a solvent, wherein R1 is H, a substituted or unsubstituted C1 C30 aliphatic hydrocarbon group, a substituted or unsubstituted C1 C30 aromatic hydrocarbon group, a substituted or unsubstituted C1 C30 alicyclic hydrocarbon group, a substituted or unsubstituted C1 C30 silyl group, a substituted or unsubstituted C1 C30 allyl group, a substituted or unsubstituted C1 C30 acyl group, a vinyl group, an amine group, an acetate group, or an alkali metal; x is 0 2; and R2 is H, a substituted or unsubstituted C1 C4 aliphatic hydrocarbon group, an acetate group, Na, or K.", "author_names": [ "" ], "corpus_id": 103771294, "doc_id": "103771294", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hardmask composition coated under photoresist and method for preparing semiconductor devices using thereof", "venue": "", "year": 2007 }, { "abstract": "A hard mask composition for a lower layer of resist is provided to realize excellent film properties and shelf stability, to allow transfer of a high quality pattern to a substrate, and to form a hard mask having excellent etching resistance against O2 plasma gas used in the subsequent etching step. A hard mask composition for a lower layer of resist comprises: an organosilane based polymer produced from the compounds represented by the formula of [R1O]3Si X, [R2O]3Si R3 and [R4O]3Si Y Si[OR5]3 in the presence of an acid catalyst; and a solvent. In the formulae, X is a C6 C30 functional group containing a substituted or non substituted aromatic ring; each of R1, R2, R4 and R5 independently represents a C1 C6 alkyl; R3 is a C1 C12 alkyl; and Y is a linking group selected from an aromatic ring, C1 C20 linear or branched, substituted or non substituted alkylene, C1 C20 alkylene group whose backbone contains an aromatic ring, heterocyclic ring, urea or isocyanurate group, and C2 C20 hydrocarbon group containing a multiple bond.", "author_names": [ "" ], "corpus_id": 103131866, "doc_id": "103131866", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hardmask composition coated under photoresist, process of producing integrated circuit devices using the same and semiconductor device produced by the process", "venue": "", "year": 2006 }, { "abstract": "A hard mask composition for a resist under layer, a method for preparing a semiconductor integrated circuit device by using the composition, and a semiconductor integrated circuit device prepared by the method are provided to improve the reproducibility of pattern, the adhesion to a resist, the resistance against a developing layer and storage stability. A hard mask composition comprises an organosilane based polymer which is prepared by the reaction of at least one kind of compound represented by [R1O]3Si R2 and has a polydispersity of 1.1 2; a solvent; and optionally an acid catalyst, wherein R1 is a C1 C5 alkyl group, an acetoxy group, or an oxime group; and R2 is H, a C1 C5 alkyl group, an aryl group, or an aralkyl group. Preferably the organosilane based polymer is represented by the formula 2, wherein R2 is H, a C1 C5 alkyl group, an aryl group, or an aralkyl group.", "author_names": [ "" ], "corpus_id": 103507029, "doc_id": "103507029", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hardmask composition coated under photoresist comprising organosilane polymer and process of producing integrated circuit devices using thereof", "venue": "", "year": 2006 }, { "abstract": "A hard mask composition under a resist layer is provided to control the quantity of an alkoxy group of a final polycondensation material by adjusting the quantity of introduced water in a hydrolysis process of a compound. An organic silane based polymerization material has an alkoxy group generated from a compound designated by the following chemical formula 1 or an alkoxy group generated from compounds designated by the following chemical formulas 1 and 2. A hard mask composition includes the organic silane based polymerization material and a solvent. The organic silane based polymerization material is a polycondensation material of a hydrolytic material designated by the following chemical formula 3 that is obtained from the compound designated by the following chemical formula 1, or a polycondensation material of a hydrolytic material designated by the following chemical formulas 3 and 4 that are respectively obtained from the compounds designated by the following chemical formulas 1 and 2. Chemical formula 1 is [RO]3Si R' wherein R is methyl or ethyl and R' is substitution or non substitution alkyl of a ring or non ring shape. Chemical formula 2 is [RO]3Si Ar wherein R is methyl or ethyl and Ar is a functional group including an aromatic ring. Chemical formula 3 is R'Si[OR]n[OH]3 n wherein R is methyl or ethyl, R' is substitution or non substitution alkyl of a ring or non ring shape, and n is 0 3. Chemical formula 4 is ArSi[OR]n[OH]3 n wherein R is methyl or ethyl, Ar is a functional group including an aromatic ring, and n is 0 3.", "author_names": [ "" ], "corpus_id": 102590882, "doc_id": "102590882", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hardmask composition coated under photoresist and process of producing integrated circuit devices using thereof", "venue": "", "year": 2006 } ]

[ { "abstract": "Due to rapid growth in semiconductor technology, there is a continuous increase of the system power and the shrinkage of size. This resulted in inevitable challenges in the field of thermal management of electronics to maintain the desirable operating temperature. The present paper reviews the literature dealing with various aspects of cooling methods. Included are papers on experimental work on analyzing cooling technique and its stability, numerical modeling, natural convection, and advanced cooling methods. The issues of thermal management of electronics, development of new effective cooling schemes by using advanced materials and manufacturing methods are also enumerated in this paper.", "author_names": [ "Sundaram Shanmuga Anandan", "Velraj Ramalingam" ], "corpus_id": 54606140, "doc_id": "54606140", "n_citations": 166, "n_key_citations": 12, "score": 1, "title": "Thermal management of electronics: A review of literature", "venue": "", "year": 2008 }, { "abstract": "Abstract Thermal interface materials (TIMs) are used extensively to improve thermal conduction across two mating parts. They are particularly crucial in electronics thermal management since excessive junction to ambient thermal resistances can cause elevated temperatures which can negatively influence device performance and reliability. Of particular interest to electronic package designers is the thermal resistance of the TIM layer at the end of its design life. Estimations of this allow the package to be designed to perform adequately over its entire useful life. To this end, TIM reliability studies have been performed using accelerated stress tests. This paper reviews the body of work which has been performed on TIM reliability. It focuses on the various test methodologies with commentary on the results which have been obtained for the different TIM materials. Based on the information available in the open literature, a test procedure is proposed for TIM selection based on beginning and end of life performance.", "author_names": [ "Jens Due", "A J Robinson" ], "corpus_id": 110737759, "doc_id": "110737759", "n_citations": 104, "n_key_citations": 4, "score": 0, "title": "Reliability of thermal interface materials: A review", "venue": "", "year": 2013 }, { "abstract": "The thermal management of magnetic components for power electronics is crucial to ensure their reliability. However, conventional thermal models for magnetic components are known to have either poor accuracy or excessive complexity. Contrary to these models, the use of Thermal Resistance Matrices is proposed in this paper instead, which combine both accuracy and simplicity. They are usually used to characterize semiconductor devices, but not for magnetic components. The guidelines to apply Thermal Resistance Matrices for magnetic components are discussed in detail. The accuracy of this model is validated by 3D FEA simulations and experimental results, showing an absolute error lower than 5 C and a relative error between 6.4% and 3.9% which is outstanding compared to the carried out literature review.", "author_names": [ "Guillermo Salinas", "Juan A Serrano-Vargas", "Javier Munoz-Anton", "Pedro Alou" ], "corpus_id": 236356328, "doc_id": "236356328", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Thermal Resistance Matrix Extraction from Finite Element Analysis for High Frequency Magnetic Components", "venue": "", "year": 2021 }, { "abstract": "BackgroundLaparoscopic sleeve gastrectomy (LSG) is a common weight loss operation that is increasingly being managed on an outpatient or overnight stay basis. The aim of this systematic review was to evaluate the available literature and develop recommendations for optimal pain management after LSG.MethodsA systematic review utilizing preferred reporting items for systematic reviews and meta analysis with PROcedure SPECific Postoperative Pain ManagemenT methodology was undertaken. Randomized controlled trials (RCTs) published in the English language from inception to September 2018 assessing postoperative pain using analgesic, anesthetic, and surgical interventions were identified from MEDLINE, EMBASE and Cochrane Databases.ResultsSignificant heterogeneity was identified in the 18 RCTs included in this systematic review. Gabapentinoids and transversus abdominis plane blocks reduced LSG postoperative pain. There was limited procedure specific evidence of analgesic effects for acetaminophen, non steroidal anti inflammatory drugs, dexamethasone, magnesium, and tramadol in this setting. Inconsistent evidence was found in the studies investigating alpha 2 agonists. No evidence was found for intraperitoneal local anesthetic administration or single port laparoscopy.ConclusionsThe literature to recommend an optimal analgesic regimen for LSG is limited. The pragmatic view supports acetaminophen and a non steroidal anti inflammatory drug, with opioids as rescue analgesics. Gabapentinoids should be used with caution, as they may amplify opioid induced respiratory depression. Although transversus abdominis plane blocks reduced pain, port site infiltration may be considered instead, as it is a simple and inexpensive approach that provides adequate somatic blockade. Further RCTs are required to confirm the influence of the recommended analgesic regimen on postoperative pain relief.", "author_names": [ "Hoani Macfater", "Weisi Xia", "Sanket Srinivasa", "Andrew G Hill", "Marc Van de Velde", "Girsh P Joshi", "On Behalf Of D C V A S Collaborators" ], "corpus_id": 59603208, "doc_id": "59603208", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Evidence Based Management of Postoperative Pain in Adults Undergoing Laparoscopic Sleeve Gastrectomy", "venue": "World Journal of Surgery", "year": 2019 }, { "abstract": "PurposeThe aim of this study was to review the available literature and define clinical practice guidelines for the use of natural agents for the prevention and treatment of oral mucositis.MethodsA systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society for Oral Oncology. The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible.ResultsA total of 49 papers across 15 interventions were examined. A new suggestion was developed in favor of systemic zinc supplements administered orally in the prevention of oral mucositis in oral cancer patients receiving radiation therapy or chemoradiation (Level III evidence) A recommendation was made against the use of intravenous glutamine for the prevention of oral mucositis in patients receiving high dose chemotherapy prior to hematopoietic stem cell transplant (Level II evidence) No guideline was possible for any other agent, due to inadequate and/or conflicting evidence.ConclusionsOf the various natural agents reviewed here, the available evidence supported a guideline only for two agents: a suggestion in favor of zinc and a recommendation against glutamine, in the treatment settings listed above. Well designed studies of other natural agents are warranted.", "author_names": [ "Noam Yarom", "Anura Ariyawardana", "Allan J Hovan", "Andrei Barasch", "Virginia Jarvis", "Siri Beier Jensen", "Yehuda Zadik", "S Elad", "Joanne M Bowen", "Rajesh V Lalla", "For the Mucositis Study Group of the Multinational Ass Oncology" ], "corpus_id": 10920964, "doc_id": "10920964", "n_citations": 85, "n_key_citations": 7, "score": 0, "title": "Systematic review of natural agents for the management of oral mucositis in cancer patients", "venue": "Supportive Care in Cancer", "year": 2013 }, { "abstract": "PurposeThe aim of this study was to review the available literature and define clinical practice guidelines for the use of agents for the prevention and treatment of gastrointestinal mucositis.MethodsA systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible.ResultsA total of 251 clinical studies across 29 interventions were examined. Panel members were able to make one new evidence based negative recommendation; two new evidence based suggestions, and one evidence based change from previous guidelines. Firstly, the panel recommends against the use of misoprostol suppositories for the prevention of acute radiation induced proctitis. Secondly, the panel suggests probiotic treatment containing Lactobacillus spp. may be beneficial for prevention of chemotherapy and radiotherapy induced diarrhea in patients with malignancies of the pelvic region. Thirdly, the panel suggests the use of hyperbaric oxygen as an effective means in treating radiation induced proctitis. Finally, new evidence has emerged which is in conflict with our previous guideline surrounding the use of systemic glutamine, meaning that the panel is unable to form a guideline. No guideline was possible for any other agent, due to inadequate and/or conflicting evidence.ConclusionsThis updated review of the literature has allowed new recommendations and suggestions for clinical practice to be reached. This highlights the importance of regular updates.", "author_names": [ "Rachel J Gibson", "Dorothy Keefe", "Rajesh V Lalla", "Emma H Bateman", "N M A Blijlevens", "Margot Fijlstra", "Emily E King", "Andrea M Stringer", "Walter J F M van der Velden", "Roger Yazbeck", "S Elad", "Joanne M Bowen", "For the Mucositis Study Group of the Multinational Ass Oncology" ], "corpus_id": 12797539, "doc_id": "12797539", "n_citations": 164, "n_key_citations": 2, "score": 0, "title": "Systematic review of agents for the management of gastrointestinal mucositis in cancer patients", "venue": "Supportive Care in Cancer", "year": 2012 }, { "abstract": "PurposeThe aim of this project was to review the available literature and define clinical practice guidelines for the use of anti inflammatory agents for the prevention and treatment of oral mucositis in cancer patients.Materials and methodsA systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. The body of evidence for use of each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible.ResultsForty one papers were reviewed. There was sufficient evidence to recommend the use of benzydamine mouthwash for the prevention of oral mucositis in head and neck cancer patients receiving moderate dose radiation therapy (up to 50 Gy) without concomitant chemotherapy. A new suggestion was developed against the use of misoprostol mouthwash for the prevention of oral mucositis in head and neck cancer patients receiving radiation therapy. Positive results were reported for some other anti inflammatory agents. However, no guidelines were able to be developed for any other agents due to insufficient and/or conflicting evidence.ConclusionsThe use of anti inflammatory agents continues to be a promising strategy for the prevention and treatment of oral mucositis. Additional well designed studies are needed to examine the use of this class of agents for oral mucositis.", "author_names": [ "Ourania Nicolatou-Galitis", "Triantafyllia Sarri", "Joanne Bowen", "Mario Palma", "V Kouloulias", "Pasquale Niscola", "Dorothea Riesenbeck", "Monique A Stokman", "Wim J E Tissing", "E M Yeoh", "S Elad", "Rajesh V Lalla", "For the Mucositis Study Group of the Multinational Ass Oncology" ], "corpus_id": 28227701, "doc_id": "28227701", "n_citations": 86, "n_key_citations": 2, "score": 0, "title": "Systematic review of anti inflammatory agents for the management of oral mucositis in cancer patients", "venue": "Supportive Care in Cancer", "year": 2013 }, { "abstract": "Purpose of ReviewThis review aims to summarize the type 1 diabetes (T1D) and weight literature with an emphasis on barriers associated with weight management, the unique T1D specific factors that impact weight loss success, maladaptive and adaptive strategies for weight loss, and interventions to promote weight loss.Recent FindingsWeight gain is associated with intensive insulin therapy. Overweight and obese weight status in individuals with T1D is higher than the general population and prevalence is rising. A variety of demographic (e.g. female sex) clinical (e.g. greater insulin needs) environmental (e.g. skipping meals) and psychosocial (e.g. depression, stress) factors are associated with overweight/obese weight status in T1D. Fear of hypoglycemia is a significant barrier to engagement in physical activity. Studies evaluating adaptive weight loss strategies in people with T1D are limited.SummaryThere is a growing literature highlighting the prevalence and seriousness of overweight and obesity among both youth and adults with T1D. There is an urgent need to develop evidence based weight management guidelines and interventions that address the unique concerns of individuals with T1D and that concurrently address glycemic control.", "author_names": [ "Kimberly A Driscoll", "Karen D Corbin", "David M Maahs", "Richard E Pratley", "Franziska K Bishop", "Anna R Kahkoska", "Korey K Hood", "Elizabeth J Mayer-Davis", "on behalf of the Advancing Care for Type 1 Diabetes a Network" ], "corpus_id": 5111522, "doc_id": "5111522", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Biopsychosocial Aspects of Weight Management in Type 1 Diabetes: a Review and Next Steps", "venue": "Current Diabetes Reports", "year": 2017 }, { "abstract": "PurposeThe aim of this project was to review the literature and define clinical practice guidelines for the use of cytokines and growth factor agents for the prevention or treatment of oral mucositis induced by cancer chemotherapy or radiotherapy.MethodsA systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society for Oral Oncology (MASCC/ISOO) The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: Recommendation, Suggestion, No guideline possible.ResultsSixty four clinical studies across 11 interventions were evaluated. A recommendation was made for the use of recombinant human KGF 1 (palifermin) at a dose of 60 mg/kg per day for 3 days prior to conditioning treatment and for 3 days post transplant for prevention of oral mucositis in patients receiving high dose chemotherapy and total body irradiation followed by autologous stem cell transplantation for hematological malignancies. A suggestion was made against using granulocyte macrophage colony stimulating factor mouthwash for the prevention of oral mucositis in the setting of high dose chemotherapy followed by autologous or allogeneic stem cell transplantation. No guideline was possible for any other cytokine or growth factor agents due to inconclusive evidence.ConclusionsOf the cytokine and growth factor agents studied for oral mucositis, the evidence only supports use of palifermin in the specific population listed above. Additional well designed research is needed on other cytokine and growth factor interventions and in other cancer treatment settings.", "author_names": [ "Judith E Raber-Durlacher", "Inger von Bultzingslowen", "Richard Logan", "Joanne M Bowen", "A R Al-Azri", "Hele Everaus", "Erich Gerber", "Jesus Garcia Gomez", "B Gosta Pettersson", "Yoshihiko Soga", "Fred K L Spijkervet", "Wim J E Tissing", "Joel B Epstein", "S Elad", "Rajesh V Lalla", "For the Mucositis Study Group of the Multinational Ass Oncology" ], "corpus_id": 9554278, "doc_id": "9554278", "n_citations": 96, "n_key_citations": 4, "score": 0, "title": "Systematic review of cytokines and growth factors for the management of oral mucositis in cancer patients", "venue": "Supportive Care in Cancer", "year": 2012 }, { "abstract": "PurposeThe aim of this study was to review the available literature from 1966 until December 31, 2010 and define clinical practice guidelines for the use of amifostine for the prevention and treatment of oral mucositis in cancer patients.MethodsA systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. The body of evidence for the use of amifostine, in each cancer treatment setting was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, or no guideline possible.ResultsThirty papers were reviewed for evidence on amifostine as an intervention for oral mucositis. No guideline was possible for amifostine in any cancer treatment setting due to inadequate and conflicting evidence.ConclusionReview of the amifostine studies for the prevention and treatment of oral mucositis has found insufficient evidence to support its use in any cancer treatment setting for this purpose. Additional well designed research is needed to clarify the role of amifostine as an intervention for oral mucositis.", "author_names": [ "Ourania Nicolatou-Galitis", "Triantafyllia Sarri", "Joanne Bowen", "Mario Palma", "V Kouloulias", "Pasquale Niscola", "Dorothea Riesenbeck", "Monique A Stokman", "Wim J E Tissing", "E M Yeoh", "S Elad", "Rajesh V Lalla", "For the Mucositis Study Group of the Multinational Ass Oncology" ], "corpus_id": 21982053, "doc_id": "21982053", "n_citations": 80, "n_key_citations": 2, "score": 0, "title": "Systematic review of amifostine for the management of oral mucositis in cancer patients", "venue": "Supportive Care in Cancer", "year": 2012 } ]

[ { "abstract": "The objective of this paper is to review the possibilities of applying fault tolerance in generator systems for wind turbines based on what has been presented in the literature. In order to make generator systems fault tolerant in a suitable way, it is necessary to gain insight into the probability of different failures, so that suitable measures can be taken. Therefore, a literature survey of reliability of wind turbines, electrical machines and power electronic converters is given. Five different ways of achieving fault tolerance identified in the literature are discussed together with their applicability for wind turbines: (1) converters with redundant semiconductors, (2) fault tolerant converter topologies, (3) fault tolerance by increasing the number of phases, (4) fault tolerance of switched reluctance machines, and (5) design for fault tolerance of PM machines and converters. Because converters fail more often than machines, it makes sense to use of fault tolerant converter topologies. Increasing the number of phases is a useful form of fault tolerance because it can be achieved without increasing the cost significantly.", "author_names": [ "Henk Polinder", "Heinz Lendenmann", "Robert Chin", "W M Arshad" ], "corpus_id": 20712988, "doc_id": "20712988", "n_citations": 46, "n_key_citations": 2, "score": 1, "title": "Fault tolerant generator systems for wind turbines", "venue": "2009 IEEE International Electric Machines and Drives Conference", "year": 2009 }, { "abstract": "Abstract In this paper, a fault tolerant model predictive control scheme is proposed for wind turbines in the partial load region to meet the control objectives in the presence of disturbances, uncertainties, sensor and actuator faults. The aim of wind turbine control systems in the partial load region is to capture maximum power by tracking the optimal generator speed. But any fault in the sensors and actuators can take away the closed loop system from the main objectives and maybe make the system unstable in some cases. At first, an online model predictive controller (MPC) is designed as a nominal controller to track the maximum power and guarantee all constraints satisfaction without considering any fault. In the next step, an adaptive sliding mode observer (SMO) is designed to estimate the actual states and sensor faults, simultaneously. Finally, an additive control law is represented and shown that it is able to tolerate the actuator faults effectively. Using extensive simulation results it is shown that the proposed strategy is able to handle the uncertainties, sensor and actuator faults in the control system, simultaneously.", "author_names": [ "Kamyar Ghanbarpour", "F Merrikh Bayat", "Abolfazl Jalilvand" ], "corpus_id": 213698729, "doc_id": "213698729", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Dependable power extraction in wind turbines using model predictive fault tolerant control", "venue": "", "year": 2020 }, { "abstract": "This paper presents an efficient technique for monitoring and control of wind turbines. Fault tolerant control (FTC) is designed using Parity Space approach to diagnose the sensor faults in the wind turbine. Based on the fault detection system an FTC scheme is proposed to accommodate and reconfigurable the control signals. The main contribution of this study is to develop a monitoring and control system of wind turbine, which reduces the system components as well as to increase the reliability and safety of wind turbines. The sensors which considered in this study are pitch position, generator speed and rotor speed sensors. Real data of wind measurement and real parameters of wind turbine is used to illustrate the proposed scheme.", "author_names": [ "Ali Abdo", "Jamal O Siam", "Ahmed Abdou", "Hakam Shehadeh", "Ashraf Al-Rimawi" ], "corpus_id": 53013534, "doc_id": "53013534", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An Efficient Approach for Fault Detection and Fault Tolerant Control of Wind Turbines", "venue": "2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC I&CPS Europe)", "year": 2018 }, { "abstract": "Fault tolerant an important role in improving reliability and availability for permanent magnet synchronous generator (PMSG) wind turbines. The open circuit (OC) faults in the machine side converter (MSC) interrupt the input AC current, which cause harmonics and DC link voltage ripple. In this paper, the OC fault of a switch of insulated gate bipolar transistors (IGBTs) in MSC was examined by changing the SVPWM switching pattern. In addition, the technique of fault tolerant was performed without the need for additional hardware and complex calculations. The validity of this paper is verified by MATLAB simulation results.", "author_names": [ "Rouhollah Bolbolnia", "Elham Heydari", "Karim Abbaszadeh" ], "corpus_id": 218564398, "doc_id": "218564398", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Fault Tolerant Control in Direct Drive PMSG Wind Turbine Systems under Open Circuit Faults", "venue": "2020 11th Power Electronics, Drive Systems, and Technologies Conference (PEDSTC)", "year": 2020 }, { "abstract": "This paper presents a fault tolerant permanent magnet synchronous generator (PMSG) drive for wind turbine systems, with the ability to handle power semiconductor open circuit (O C) faults in the full scale back to back converter. The fault tolerant topology consists of a five leg converter, with a shared leg connected to a generator phase and to its corresponding grid phase. The main contribution of this paper consists on the development of an alternative vector control based pulse width modulation (PWM) control scheme for both machine side converter (MSC) and grid side converter (GSC) allowing to reduce the dc bus voltage ratings. Moreover, a reliable fault diagnosis algorithm is also integrated, providing the information required to instantaneously trigger fault tolerant remedial strategies, without any additional sensors. Simulation and experimental results are presented to validate the effectiveness of the proposed fault tolerant PMSG drive.", "author_names": [ "Imed Jlassi", "Fernando Bento", "Antonio Joao Marques Cardoso" ], "corpus_id": 57361857, "doc_id": "57361857", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Fault Tolerant PMSG Direct Drive Wind Turbines, using Vector Control Techniques with Reduced DC Link Ratings", "venue": "IECON 2018 44th Annual Conference of the IEEE Industrial Electronics Society", "year": 2018 }, { "abstract": "In wind turbines (WTs) some faults can induce saturation of the control signal, and these saturation nonlinearities might lead to instability. Therefore, a robust system against saturation can better deal with faults. In this work, an avoid saturation strategy is proposed for the torque control of WTs. The key idea is that the reference power and generator speed set points are hysterically manipulated. Simulation results from a 5MW benchmark model show that the proposed strategy has a clear added value with respect to the baseline controller not only in healthy condition but also in presence of a realistic fault.", "author_names": [ "Leonardo Acho", "Jose Rodellar", "Christian Tutiven", "Yolanda Vidal" ], "corpus_id": 41505278, "doc_id": "41505278", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Passive fault tolerant control strategy in controlled wind turbines", "venue": "2016 3rd Conference on Control and Fault Tolerant Systems (SysTol)", "year": 2016 }, { "abstract": "This paper presents a test benchmark model for the evaluation of fault detection and accommodation schemes. This benchmark model deals with the wind turbine on a system level, and it includes sensor, actuator, and system faults, namely faults in the pitch system, the drive train, the generator, and the converter system. Since it is a system level model, converter and pitch system models are simplified because these are controlled by internal controllers working at higher frequencies than the system model. The model represents a three bladed pitch controlled variable speed wind turbine with a nominal power of 4.8 MW. The fault detection and isolation (FDI) problem was addressed by several teams, and five of the solutions are compared in the second part of this paper. This comparison relies on additional test data in which the faults occur in different operating conditions than in the test data used for the FDI design.", "author_names": [ "Peter Fogh Odgaard", "Jakob Stoustrup", "Michel Kinnaert" ], "corpus_id": 14670048, "doc_id": "14670048", "n_citations": 319, "n_key_citations": 49, "score": 0, "title": "Fault Tolerant Control of Wind Turbines: A Benchmark Model", "venue": "IEEE Transactions on Control Systems Technology", "year": 2013 }, { "abstract": "Fault diagnosis and fault tolerant control of modern wind turbines with minimum hardware requirements are mandatory features in order to increase the reliability and availability levels with low costs. This paper presents a fault tolerant permanent magnet synchronous generator (PMSG) drive for wind turbine systems, allowing to automatically reconfigure the drive operation when a current sensor fault and a power switch open circuit failure in the back to back converter occurs. Accordingly, the fault can be distinguished and the faulty device is correctly localized in both cases, based on a single fault diagnostic technique. For the power switch post fault operation, a fault tolerant converter topology is proposed with minimum number of extra components and with a simple control modification. In addition, an effective algorithm is proposed for current sensor post fault operation without using extra devices. In order to prove the performance of the proposed fault tolerant PMSG drive, several simulation results are presented.", "author_names": [ "Imed Jlassi", "Sejir Khojet El Khil", "Najiba Mrabet Bellaaj" ], "corpus_id": 22240713, "doc_id": "22240713", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Power switch and current sensor fault tolerant control of PMSG drives for wind turbine systems", "venue": "2015 IEEE 10th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED)", "year": 2015 }, { "abstract": "In this paper, a scheme for an integrated design of fault tolerant control (FTC) systems for a wind turbine benchmark is proposed, with focus on the overall performance of the system. For that a key performance indicator (KPI) which reflects the economic performance of the system is defined, and the objective of the proposed FTC scheme is to maintain the system KPI in the admissible range in faulty conditions. The basic idea behind this scheme is data driven design of the proposed fault tolerant architecture whose core is an observer/residual generator based realization of the Youla parameterization of all stabilizing controllers with an embedded residual generator for fault detection (FD) purpose. The performance and effectiveness of the proposed scheme are demonstrated through the wind turbine benchmark model proposed in [1]", "author_names": [ "Hao Luo", "Steven X Ding", "Adel Haghani", "Haiyang Hao", "Shen Yin", "Torsten Jeinsch" ], "corpus_id": 21153457, "doc_id": "21153457", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Data driven design of KPI related fault tolerant control system for wind turbines", "venue": "2013 American Control Conference", "year": 2013 }, { "abstract": "Inaccuracy in linear modeling of wind turbines, effects of wind speed disturbance, and faults in components of the closed loop system increase the need for advanced controllers in wind energy conversion systems. In this article, an adaptive pitch controller is developed to regulate the generator speed in region 3. Also, an adaptive feed forward term is augmented to improve the generator speed regulation in presence of the wind speed disturbance. Parameters of the controller are adaptively adjusted based on the improved dead zone modification rule that guarantees closed loop stability and zero regulation error in presence of the unstructured modeling uncertainties, step like wind speed disturbance, and faults in pitch actuator. Proposed controller is compared to the baseline proportional integral controller for controls advanced research turbine. Simulation results confirm the improvement in closed loop regulation performance with proposed robust adaptive controller.", "author_names": [ "Vahid Rezaei", "Farzad Rajaei Salmasi" ], "corpus_id": 110167491, "doc_id": "110167491", "n_citations": 9, "n_key_citations": 1, "score": 0, "title": "Robust Adaptive Fault Tolerant Pitch Control of Wind Turbines", "venue": "", "year": 2014 } ]

[ { "abstract": "We have studied the spin dynamics in self organized InAs/GaAs quantum dots by time resolved photoluminescence performed under strictly resonant excitation. At low temperature, we observe strictly no decay of both the linear and the circular luminescence polarization. This demonstrates that the carrier spins are totally frozen on the exciton lifetime scale.", "author_names": [ "M P Le Paillard", "Xavier Marie", "P Renucci", "Thierry Amand", "A Jbeli", "J M Gerard" ], "corpus_id": 27560588, "doc_id": "27560588", "n_citations": 331, "n_key_citations": 4, "score": 1, "title": "Spin relaxation quenching in semiconductor quantum dots.", "venue": "Physical review letters", "year": 2001 }, { "abstract": "The spin injection into GaAs has been studied for the ferromagnetic metal MnAs. Evidence for preferential minority spin injection is obtained from the circular polarization of the electroluminescence in GaAs/(In,Ga)As light emitting diodes (LED) The spin injection efficiency of 6% at the MnAs/GaAs interface is estimated on the basis of spin relaxation times extracted from time resolved photoluminescence measurements. This efficiency, as well as the preferential spin orientation, resembles very much the injection behavior found for epitaxial Fe layers. The results do not depend on the azimuthal orientation of the epitaxial MnAs injection layer.", "author_names": [ "Manfred Ramsteiner", "H -Y Hao", "Atsushi Kawaharazuka", "H J Zhu", "Martin Kastner", "R Hey", "L Daweritz", "Holger T Grahn", "K H Ploog" ], "corpus_id": 56444167, "doc_id": "56444167", "n_citations": 170, "n_key_citations": 2, "score": 0, "title": "Electrical spin injection from ferromagnetic MnAs metal layers into GaAs", "venue": "", "year": 2002 }, { "abstract": "The magnitude and sign of the effective magnetic splitting factor g* for conduction electrons in GaAs/AlxGa(1 x)As quantum wells have been determined as a function of well width down to 5 nm. The experimental method is based on combined measurements of the decay time of photoluminescence and of the suppression of its circular polarization under polarized optical pumping in a magnetic field perpendicular to the growth axis (Hanle effect) Measurements as a function of hole sheet density in the wells reveal a transition from excitonic behavior with very small apparent g value for low density, to larger absolute values characteristic of free electrons at higher densities. For 20 nm wells g* for electrons is close to the bulk value 0.44) and increases for narrower wells passing through zero for well width close to 5.5 nm. A theoretical analysis based on three band k.p theory, including allowance for conduction band nonparabolicity and for wave function penetration into the barriers, gives a reasonable representation of the data, leading to the conclusion that g* in quantum wells has a value close to that of electrons in the bulk at the confinement energy above the band minimum.", "author_names": [ "" ], "corpus_id": 45247336, "doc_id": "45247336", "n_citations": 131, "n_key_citations": 3, "score": 0, "title": "Magnetic g factor of electrons in GaAs/AlxGa1 xAs quantum wells.", "venue": "Physical review. B, Condensed matter", "year": 1991 }, { "abstract": "We calculate for the first time the circular polarization of GaAs/\\mathrm{Ga}}_{1\\mathrm{\\ensuremath{ \\mathrm{x}\\mathrm{Al}}_{\\mathrm{x}$As quantum well photoluminescence taking into account the true nonparabolic valence band structure. Versus the excitation energy, we find high positive polarization for the transition n=1 heavy hole\\char21{}to\\char21{}conduction band transition and negative polarization at the onset of n=1 light hole\\char21{}to\\char21{}conduction band transition in qualitative agreement with experiments. We also study the \\mathrm{Ga}}_{\\mathrm{y}\\mathrm{In}}_{1\\mathrm{\\ensuremath{ \\mathrm{y}$As/InP system and predict no negative polarization in this case.", "author_names": [ "" ], "corpus_id": 41905031, "doc_id": "41905031", "n_citations": 81, "n_key_citations": 0, "score": 0, "title": "Variational calculation of polarization of quantum well photoluminescence.", "venue": "Physical review. B, Condensed matter", "year": 1987 }, { "abstract": "GaAs/AlAs pillar microcavities with elliptical cross section have been fabricated by molecular beam epitaxy, electron beam lithography, and reactive ion etching. We study their lowest energy confined photonic modes by photoluminescence, using a quantum box array placed inside the cavity as an internal broadband light source. Such an anisotropic cross section allows to split the twofold polarization degenerate fundamental mode of circular micropillars into a pair of orthogonal linearly polarized modes. Their energy splitting, which is well accounted for by a simple perturbative model, is studied experimentally and theoretically as a function of the eccentricity and average radius of the pillars. Splittings as large as 15 meV are observed, which is very encouraging for applications ranging from the improvement of the polarization locking in vertical cavity lasers to the fabrication of light emitting diodes with a better control of the spontaneous emission.", "author_names": [ "B Gayral", "J M Gerard", "Bernard Legrand", "Eric Costard", "Veronique Thierry-Mieg" ], "corpus_id": 123496305, "doc_id": "123496305", "n_citations": 81, "n_key_citations": 2, "score": 0, "title": "Optical study of GaAs/AlAs pillar microcavities with elliptical cross section", "venue": "", "year": 1998 }, { "abstract": "We observed a circular photogalvanic effect (CPGE) in GaAs quantum wells at inter band excitation. The spectral dependence of the CPGE is measured together with that of the polarization degree of the time resolved photoluminescence. A theoretical model takes into account spin splitting of conduction and valence bands.", "author_names": [ "Vassilij V Bel'kov", "Sergey D Ganichev", "Petra Schneider", "C G Back", "Morgan Oestereich", "Jens Rudolph", "D Haegele", "Leonid E Golub", "Werner Wegscheider", "Wilhelm Prettl" ], "corpus_id": 67764493, "doc_id": "67764493", "n_citations": 46, "n_key_citations": 1, "score": 0, "title": "Circular photogalvanic effect at inter band excitation in semiconductor quantum wells", "venue": "", "year": 2003 }, { "abstract": "We report on optical orientation experiments in individual strain free GaAs quantum dots in AlGaAs grown by droplet epitaxy. Circularly polarized optical excitation yields strong circular polarization of the resulting photoluminescence at 4 K. Optical injection of spin polarized electrons into a dot gives rise to dynamical nuclear polarization that considerably changes the exciton Zeeman splitting (Overhauser shift) We show that the created nuclear polarization is bistable and we present a direct measurement of the buildup time of the nuclear polarization in a single GaAs dot in the order of 1 s.", "author_names": [ "Thomas Belhadj", "Takashi Kuroda", "Claire-Marie Simon", "Thierry Amand", "Takaaki Mano", "Kazuaki Sakoda", "Nobuyuki Koguchi", "Xavier Marie", "Bernhard Urbaszek" ], "corpus_id": 119099142, "doc_id": "119099142", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Optically monitored nuclear spin dynamics in individual GaAs quantum dots grown by droplet epitaxy", "venue": "", "year": 2008 }, { "abstract": "Luminescence spectra of interwell excitons in GaAs/AlGaAs double quantum wells with electric field tilted bands (n i n) structures were studied. In these structures the electron and the hole in the interwell exciton are spatially separated between neighboring quantum wells by a narrow AlAs barrier. Under resonant excitation by circularly polarized light the luminescence line of the interwell excitons exhibited appreciable narrowing as their concentration increased and the degree of circular polarization of the photoluminescence increased substantially. Under resonant excitation by linearly polarized light the alignment of the interwell excitons increased as a threshold process with increasing optical pumping. By analyzing time resolved spectra and the kinetics of the photoluminescence intensity under pulsed excitation it was established that under these conditions the rate of radiative recombination increases substantially. The observed effect occurs at below critical temperatures and is interpreted in terms of the collective behavior of the interwell excitons. Studies of the luminescence spectra in a magnetic field showed that the collective exciton phase is dielectric and in this phase the interwell excitons retain their individual properties.", "author_names": [ "A V Larionov", "Vladislav B Timofeev", "Jorn Marcher Hvam", "K Soerensen" ], "corpus_id": 54850167, "doc_id": "54850167", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Interwell excitons in GaAs/AlGaAs double quantum wells and their collective properties", "venue": "", "year": 2000 }, { "abstract": "The authors have demonstrated by electroluminescence the injection of spin polarized electrons through Co/Al2O3/GaAs tunnel barrier into p doped InAs/GaAs quantum dots embedded in a p i n GaAs light emitting diode. The spin relaxation processes in the p doped quantum dots are characterized independently by optical measurements (time and polarization resolved photoluminescence) The measured electroluminescence circular polarization is about 15% at low temperature in a 2T magnetic field, proving an efficient electrical spin injection yield in the quantum dots. Moreover, this electroluminescence circular polarization is stable up to 70K.", "author_names": [ "Laurent Lombez", "P Renucci", "Pascal Gallo", "P F Braun", "Helene Carrere", "P H Binh", "Xavier Marie", "Thierry Amand", "Bernhard Urbaszek", "J -L Gauffier", "Thierry Camps", "Alexandre Arnoult", "Chantal Fontaine", "Cyrile Deranlot", "Richard Mattana", "Henri Jaffres", "J -M George" ], "corpus_id": 119489715, "doc_id": "119489715", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Electrical spin injection into p doped quantum dots through a tunnel barrier", "venue": "", "year": 2007 }, { "abstract": "The nuclear spin dynamics in an ensemble of singly charged (In,Ga)As/GaAs quantum dots has been studied at a temperature of 1.6 K. The effective magnetic field of nuclear polarization was detected through the circular polarization of quantum dot photoluminescence. The polarization is reduced if an external magnetic field compensates the nuclear field. To study the time evolution of the nuclear field, a photoluminescence pump probe technique has been developed, from which we find a complex behavior of the nuclear polarization dynamics; its rise is considerably slowed down when the effective field of polarized nuclei exceeds that of the nuclear spin fluctuations. A phenomenological model for the dynamics of a strongly coupled electron nuclear spin system has been developed, whose results qualitatively agree with the experimental data.", "author_names": [ "Roman V Cherbunin", "S Y Verbin", "Thomas Auer", "D R Yakovlev", "Dirk Reuter", "Andreas Dirk Wieck", "Il'ya Ya Gerlovin", "I V Ignatiev", "Dmitry V Vishnevsky", "Manfred Bayer" ], "corpus_id": 122178494, "doc_id": "122178494", "n_citations": 28, "n_key_citations": 2, "score": 0, "title": "Dynamics of the nuclear spin polarization by optically oriented electrons in a (In,Ga)As/GaAs quantum dot ensemble", "venue": "", "year": 2009 } ]

[ { "abstract": "Abstract Semiconductor diode detectors coated with neutron reactive materials are generally fashioned as planar diodes coated with 10B, 6LiF, or Gd. Planar detectors coated with 10B or 6LiF are limited to less than 5% intrinsic thermal neutron detection efficiency. Detectors coated with Gd can achieve higher efficiencies, but the low energy signatures are problematic in the presence of background radiations. Microstructured semiconductor neutron detectors (MSNDs) can now achieve a tenfold increase in neutron detection efficiency over the planar diode designs. These semiconductor neutron detectors are fashioned with a matrix of microstructured patterns etched deeply into the semiconductor substrate and, subsequently, backfilled with neutron reactive materials. Intrinsic thermal neutron detection efficiencies exceeding 35% have been achieved with devices no thicker than 1 mm while operating on less than 5 V, now allowing for instrumentation to be realized with similar performance as 3He gas filled detectors.", "author_names": [ "Douglas S Mcgregor", "Steven L Bellinger", "Ryan G Fronk", "Luke C Henson", "David E Huddleston", "Taylor R Ochs", "J Shultis", "Timothy J Sobering", "R D Taylor" ], "corpus_id": 92931138, "doc_id": "92931138", "n_citations": 23, "n_key_citations": 1, "score": 1, "title": "Development of Compact High Efficiency Microstructured Semiconductor Neutron Detectors", "venue": "", "year": 2015 }, { "abstract": "Abstract High efficiency Microstructured Semiconductor Neutron Detectors (MSNDs) have been tiled and arranged in a cylindrical form factor in order to serve as a direct replacement to aging and increasingly expensive 3 He gas filled proportional neutron detectors. Two 6 in long by 2 in diameter cylinders were constructed and populated with MSNDs which were then directly compared to a 4 atm Reuter Stokes 3 He detector of the same dimensions. The Generation 1 MSND based 3 Helium Replacement (HeRep Mk I) device contained sixty four 1 cm 2 active area MSNDs, each with an intrinsic neutron detection efficiency of approximately 7% A Generation 2 device (the HeRep Mk II) was populated with thirty 4 cm 2 active area MSNDs, with an intrinsic thermal neutron detection efficiency of approximately 30% The MSNDs of each HeRep were integrated to count as a single device. The 3 He proportional counter and the HeRep devices were tested while encased in a cylinder of high density polyethylene measuring a total of 6 in by 9 in. The 3 He counter and the HeRep Mk II were each placed 1 m from a 54 ng 252 Cf source and tested for efficiency. The 3 He proportional counter had a net count rate of 17.13+ 0.10 cps at 1 m. The HeRep Mk II device had a net count rate of 17.60+ 0.10 cps, amounting to 102.71+ 2.65% of the 3 He gas counter while inside of the moderator. Outside of moderator, the 3 He tube had a count rate of 3.35+ 0.05 cps and the HeRep Mk II device reported 3.19+ 05, amounting to 95.15+ 9.04% of the 3 He neutron detector.", "author_names": [ "Ryan G Fronk", "Steven L Bellinger", "Luke C Henson", "David E Huddleston", "Taylor R Ochs", "Timothy J Sobering", "Douglas S Mcgregor" ], "corpus_id": 123623664, "doc_id": "123623664", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "High efficiency microstructured semiconductor neutron detectors for direct 3He replacement", "venue": "", "year": 2015 }, { "abstract": "Silicon diodes with large aspect ratio 3D microstructures backfilled with 6LiF show a significant increase in neutron detection efficiency beyond that of conventional thin film coated planar devices. Described in this work are advancements in the technology using detector stacking methods and summed detector 6x6 element arraying methods to dramatically increase the sensitivity to thermal neutrons. The intrinsic detection efficiency of the 6x6 array for normal incident 0.0253 eV neutrons was found 6.8% compared against a calibrated 3He proportional counter.", "author_names": [ "Steven L Bellinger", "Ryan G Fronk", "Timothy J Sobering", "Douglas S Mcgregor" ], "corpus_id": 13615534, "doc_id": "13615534", "n_citations": 27, "n_key_citations": 1, "score": 0, "title": "High efficiency microstructured semiconductor neutron detectors that are arrayed, dual integrated, and stacked.", "venue": "Applied radiation and isotopes including data, instrumentation and methods for use in agriculture, industry and medicine", "year": 2012 }, { "abstract": "Dual Sided Microstructured Semiconductor Neutron Detectors (DS MSNDs) are continually being developed as a compact, low power, high efficiency alternative to 3He for thermal neutron detection. DS MSNDs are fabricated from 1.5 mm thick, 5 kOhm cm resistivity, silicon wafers. Deep trenches are etched into both sides of the silicon substrate with the back side trenches offset from the front side trenches to eliminate neutron free streaming paths through the silicon fins. A pvp type vertical diode is formed within the trench microstructures on both sides of the substrate. The trenches are then backfilled with 6LiF powder with powder packing fractions as high as 55% Incident neutrons are absorbed by 6Li atoms, which then fission and emit charged particle reaction products that can deposit energy in the adjacent silicon fins. Electron hole pairs created by the charged particle interactions are then drifted, and the current induced in the electrodes is integrated to form a voltage pulse that can be counted. So far, DS MSNDs have achieved detection efficiencies as high as 69.3% The present work describes efforts to improve the signal to noise ratio of the DS MSNDs to increase the gamma ray rejection ratio of the detectors. Silvaco TCAD simulations indicate alternative doping profiles can improve the charge collection efficiency and produce single polarity pulses regardless of interaction location, whereas the polarity of the previously reported DS MSND pulse was dependent on the location of the neutron interaction. Newly fabricated DS MSNDs will be used to populate Modular Radiation Detectors (MRD) which will be integrated into a high sensitivity Reconfigurable Wearable Detector (RWD) In addition to neutron detection, the MRDs will incorporate a high energy resolution gamma ray spectrometer for gamma ray source detection and identification. The RWD will be a highly versatile, low cost, low power, tool for the search, localization, and identification of radioactive material.", "author_names": [ "Taylor R Ochs", "Jacob M Terrell", "R M Hutchins", "K Scott DeMint", "Steven L Bellinger", "Luke C Henson", "Douglas S Mcgregor" ], "corpus_id": 215738682, "doc_id": "215738682", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Present Status of the Dual Sided Microstructured Semiconductor Neutron Detector (DS MSND) and Instrumentation", "venue": "2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)", "year": 2019 }, { "abstract": "Interest in high efficiency replacements for thin film coated thermal neutron detectors led to the development of single sided microstructured semiconductor neutron detectors (MSNDs) MSNDs are designed with micro sized trench structures that are etched into a vertically oriented pvnjunction diode, and backfilled with a neutron converting material, such as LiF. Neutrons absorbed by the converting material produce a pair of charged particle reaction products that can be measured by the diode substrate. MSNDs have higher neutron absorption and reaction product counting efficiencies than their thin film coated counterparts, resulting in up to a 10x increase in intrinsic thermal neutron detection efficiency. The detection efficiency for a single sided MSND is reduced by neutron streaming paths between the conversion material filled regions that consequently allow neutrons to pass undetected through the detector. Previously, the highest reported intrinsic thermal neutron detection efficiency for a single MSND was approximately 30% Methods for double stacking and aligning MSNDs to reduce neutron streaming produced devices with an intrinsic thermal neutron detection efficiency of 42% Presented here is a new type of MSND that features a complementary second set of trenches that are etched into the back side of the detector substrate. These dual sided microstructured semiconductor neutron detectors (DSMSNDs) have the ability to absorb and detect neutrons that stream through the front side, effectively doubling the detection efficiency of a single sided device. DS MSND sensors are theoretically capable of achieving greater than 80% intrinsic thermal neutron detection efficiency for a 1 mm thick device. Prototype DS MSNDs with diffused pvp junction operated at 0 V applied bias have achieved 53.54+ 0.61% exceeding that of the single sided MSNDs and double stacked MSNDs to represent a new record for detection efficiency for such solid state devices. Dual side etched microstructured semiconductor neutron detectors", "author_names": [ "Ryan G Fronk" ], "corpus_id": 136268170, "doc_id": "136268170", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Dual side etched microstructured semiconductor neutron detectors", "venue": "", "year": 2017 }, { "abstract": "Perforated semiconductor neutron detectors are compact diode detectors that operate at low power and can be fashioned to have high thermal neutron detection efficiency. Fabricated from high purity Si wafers, the perforations are etched into the diode surface with ICP RIE and backfilled with 6 LiF neutron reactive material. The intrinsic thermal neutron detection efficiency depends upon many factors, including the perforation geometry, size, and depth. Devices were fabricated from high resistivity 10 kO cm n type Si with conformal p type shallow junction diffusions into the perforations, which demonstrate improved neutron detection performance over previous selectively diffused designs. A comparison was made to previous selectively diffused designs, and pulse height spectra show improved signal to noise ratio, higher neutron counting efficiency, and excellent gamma ray discrimination. Devices with 20 daverageThmm wide 100mm deep sinusoidal trenches yielded intrinsic thermal neutron detection efficiencies of 11:9470:078%", "author_names": [ "Douglas S Mcgregor", "Walter J McNeil", "Steven L Bellinger", "Troy C Unruh", "J Shultis" ], "corpus_id": 122779937, "doc_id": "122779937", "n_citations": 67, "n_key_citations": 1, "score": 0, "title": "Microstructured semiconductor neutron detectors", "venue": "", "year": 2009 }, { "abstract": "Microstructured semiconductor neutron detectors (MSNDs) represent a compact, low cost, high efficiency means of solid state thermal neutron detection. Trenches are etched into a 1 cm2 or 4 cm2 active area pn junction diode and backfilled with 6LiF neutron converting material. Charged particle reaction products produced from neutron capture within the conversion material can be measured to indicate the presence of neutrons. MSNDs can be arranged into larger instruments due to their small size, high efficiency, and low power consumption. A small, inexpensive electronics package named the `Domino' was developed to facilitate the deployment of the MSND(tm) technology. The Domino is a complete electronics package that supports a single MSND(tm) with all necessary signal processing electronics. The Domino electronics were tiled together to form large area arrays and portable detector arrays. Both were characterized with a small 252Cf source. A hand held portable `Briefcase' detector with 84 Dominoes(tm) forming a 30 cm x 38 cm array, weighed 21 lbs. A vehicle portable `Panel Array' detector with 480 Dominoes formed a 1 m x 1 m. For a bare 252Cf source, the `Briefcase' detector and the `Panel Array' detector yielded 0.27 0.01 cps ng 1 (at 2 m) and 0.45 0.01 cps ng 1 (at 5 m) respectively. Modified Domino packages (with upgraded MSNDs) were arranged into a 2 in. diameter, 6 in. long cylindrical form factor (HeRep Mk II) for direct 3He replacement, matching the efficiency of a 4 atm 3He with similar dimensions. A third generation helium replacement (HeRep Mk III) was constructed to replace more compact 3He form factors, with a 0.75 in. diameter and 4.5 in. length. Populated with dual sided MSNDs, this detector yielded 0.293 0.003 cps ng 1 for bare 252Cf at 0.2 m.", "author_names": [ "Ryan G Fronk", "Steven L Bellinger", "Luke C Henson", "David E Huddleston", "Taylor R Ochs", "Michael A Reichenberger", "Cody J Rietcheck", "Colten T Smith", "Timothy J Sobering", "J Shultis", "Douglas S Mcgregor" ], "corpus_id": 12289334, "doc_id": "12289334", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Advancements in microstructured semiconductor neutron detector (MSND) based instruments", "venue": "2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)", "year": 2015 }, { "abstract": "Perforated semiconductor neutron detectors are compact diode detectors that operate at low power and can be fashioned to have high thermal neutron detection efficiency. Fabricated from high purity Si wafers, the perforations are etched into the diode surface with ICP RIE and backfilled with LiF neutron reactive material. The intrinsic thermal neutron detection efficiency depends upon many factors, including the perforation geometry, size, and depth. Devices were fabricated from high resistivity 10 kO cm n type Si with conformal p type shallow junction diffusions into the perforations, which demonstrate improved neutron detection performance over previous selectively diffused designs. A comparison was made to previous selectively diffused designs, and pulse height spectra show improved signal to noise ratio, higher neutron counting efficiency, and excellent gamma ray discrimination. Devices with 20 daverageThmm wide 100mm deep sinusoidal trenches yielded intrinsic thermal neutron detection efficiencies of 11:9470:078% 2009 Elsevier B.V. All rights reserved.", "author_names": [ "Douglas S Mcgregor", "Walter J McNeil", "Steven L Bellinger", "Troy C Unruh", "J Shultis" ], "corpus_id": 45840666, "doc_id": "45840666", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Author s personal copy Microstructured semiconductor neutron detectors", "venue": "", "year": 2009 }, { "abstract": "There is an increased demand of neutron detectors for security applications requiring detection of special nuclear materials (SNMs) to prevent proliferation and illegitimate trafficking, for monitoring neutron beams, etc. [1][2] Commonly, 3 He and BF3 gas detectors are being used for such applications due their high efficiencies. However, these detectors suffer from certain issues such as global shortage of 3 He, toxicity of BF3, portability, etc. Therefore, in recent years, there has been a significant interest in the development of semiconductor based, mainly silicon based thermal neutron detectors as an alternative to these gas filled detectors. Silicon detectors have advantages of compactness, low operating voltage requirement and low cost due to well established fabrication technology and possibility of large scale production [2] Planar structured silicon based thermal neutron detectors, where a detector is coated or integrated with the converter material/layer (commonly 10 B due to high thermal neutron absorption cross section of 3800 barn) are reported to have maximum efficiency in the range 2 3% This low efficiency is the consequence of limitations on convertor material/layer thickness due to self absorption of the secondary charged particles produced in the interaction of neutron with converter material 10 B (n, a) 7 Li) One of the ways for improving the efficiency of silicon based neutron detector is to increase the thickness of 10 B by making the trenches or array of pillars filled with 10 B. We have initiated the development of a high efficiency 3D structured thermal neutron detector having array of PIN diode pillars filled with 10 B. Initial simulation results for optimizing the geometrical parameters of the 3D pillar structured thermal neutron detector are presented in this paper. Simulation studies", "author_names": [ "Ashutosh Kumar Singh", "Anita Topkar" ], "corpus_id": 221966435, "doc_id": "221966435", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Simulation studies for optimization of geometrical parameters of 3D neutron detectors", "venue": "", "year": 2020 }, { "abstract": "Low power microstructured semiconductor neutron detector (MSND) devices have long been investigated as a high efficiency replacement for thin film diodes for solid state thermal neutron detection. Improvements in detection efficiency were made by integrating two stacked 1 cm2 devices to function as a single detector, achieving over 42% intrinsic thermal neutron detection efficiency. The need for larger active area devices led to the development of the Arrayed Device which combined seventy two dual stacked 1 cm2 devices to act as a single large area detector in a 6x6 configuration, providing an active detector area of 36 cm2. A new development in large active area devices has led to high quality 4 cm2 individual devices arrayed into a detector array comprised of 16 of individual perforated devices, at 64 cm2, providing a 78% increase in active area over the previously reported 6x6 element. Nine of the 4x4 4 cm2 elements are then integrated together into the Very Large Area Panel Array (VLAPA) with total device dimensions of 11.125\"x11.125\"x0.5\" without moderator. The elements work to function as a single VLAPA with an effective active detection area of 576 cm2. The VLAP A has been found to have an intrinsic efficiency of 2.21+ 0.02% with 2 inches HDPE on the front and back for an unmoderated 252Cf source.", "author_names": [ "Steven L Bellinger", "B William Cooper", "Nathanial R Crawford", "Ryan G Fronk", "Timothy J Sobering", "Russell D Taylor", "Douglas S Mcgregor" ], "corpus_id": 13624520, "doc_id": "13624520", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Very large area multi element microstructured semiconductor neutron detector panel array", "venue": "2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)", "year": 2012 } ]

[ { "abstract": "Abstract In this paper, an Anti lock braking system (ABS) is designed using a fuzzy logic controller (FLC) The FLC is designed in 0.35 mm standard CMOS process and this design of the circuit makes it having high speed and low power consumption. Also, all the controlling signals and input signals are in voltage form and there is no need for digital programming. Voltage mode design of the circuits leads to the convenient use of FLC with sensors. The objective function is designed to keep the wheel slip to a desired level so that maximum wheel tractive force and maximum vehicle deceleration are achieved. By training this function to the Adaptive Nero Fuzzy Inference System (ANFIS) of MATLAB software the main parameters of fuzzy controller singletons and shape of Membership Function Generators (MFGs) are measured, then all the circuits of the proposed fuzzy logic controller is designed using Complementary Metal Oxide Semiconductor (CMOS) circuits, at the end simulation results of the fuzzy logic controller using Hspice simulator and BSIM3v3 (Berkeley Short Channel Insulated gate field effect transistor Model) parameters verifies the performance and functionality of the design.", "author_names": [ "Majid Mokarram", "Abdollah Khoei", "Khayrollah Hadidi" ], "corpus_id": 165105612, "doc_id": "165105612", "n_citations": 7, "n_key_citations": 0, "score": 2, "title": "A fuzzy Anti lock braking system (ABS) controller using CMOS circuits", "venue": "Microprocess. Microsystems", "year": 2019 }, { "abstract": "Anti lock braking system (ABS) is an active safety system for vehicle, it operates by preventing the wheels from locking up during braking. According to a lot of research, the effectiveness of ABS in reducing crashes is significant. To design the ABS system, establishing an ABS test bench, which is capable for analyzing the ABS braking performance, the individual ABS components performance, and the whole ABS durability is necessary. In this work, we upgraded our original hydraulic control unit performance test bench to satisfy the above mentioned goals by further enhancing the function in this module test bench and further designing and realizing an ABS dynamic braking performance test bench. The module test bench can be used for evaluating the performance of whole ABS product quickly and precisely. In addition, the durability of the hydraulic control units and the control logic of the ABS can be performed and analyzed by the aid of a virtual speed signal circuit built in this test bench. On the other hand, the designed ABS dynamic performance test bench is aimed for testing the braking performance of ABS by using the flywheel design to simulate the field test environment. Finally, These two test benches are eventually integrated to form a versatile test platform. Through the effort, in the future, it is possible to perform effective performance assessment on commercial ABS systems and to develop new control strategies based on this test platform.", "author_names": [ "Shu-Heng Guo", "Chunliang Wu", "Kuo-Shen Chen" ], "corpus_id": 196203748, "doc_id": "196203748", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Design and Realization a Versatile Performance Test Platform for Motorcycle Anti lock Braking System", "venue": "", "year": 2019 }, { "abstract": "With the development of in wheel technology (IWT) the design of the electric vehicles (EV) is getting much improved. The anti lock braking system (ABS) which is a safety benchmark for automotive braking, is particularly important. Installing the braking motor at each fixed position of the wheel improves the intelligent control of each wheel. The nonlinear ABS with robustness performance is highly needed during the vehicle's braking. The anti lock braking controller (CAB) designed in this paper considered the well known adhesion force, the resistance force from air and the wheel rolling friction force, which bring the vehicle model closer to the real situation. A sliding mode wheel slip ratio controller (SMWSC) is proposed to yield anti lock control of wheels with an adaptive sliding surface. The vehicle dynamics model is established and simulated with consideration of different initial braking velocities, different vehicle masses and different road conditions. By comparing the braking effects with various CAB parameters, including stop distance, braking torque and wheel slip ratio, the SMWSC proposed in this paper has superior fast convergence and stability characteristics. Moreover, this SMWSC also has an added road detection module, which makes the proposed braking controller more intelligent. In addition, the important brain of this proposed ABS controller is the control algorithm, which can be used in all vehicles' ABS controller design.", "author_names": [ "Jinhong Sun", "Xiangdang Xue", "Ka Wai Eric Cheng" ], "corpus_id": 198477121, "doc_id": "198477121", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Fuzzy Sliding Mode Wheel Slip Ratio Control for Smart Vehicle Anti Lock Braking System", "venue": "Energies", "year": 2019 }, { "abstract": "This paper presents a regenerative anti lock braking system control method with road detection capability. The aim of the proposed methodology is to improve electric vehicle safety and energy economy during braking maneuvers. Vehicle body longitudinal deceleration is used to estimate a road surface. Based on the estimation results, the controller generates an appropriate braking torque to keep an optimal for various road surfaces wheel slip and to regenerate for a given motor the maximum possible amount of energy during vehicle deceleration. A fuzzy logic controller is applied to fulfill the task. The control method is tested on a four in wheel motor drive sport utility electric vehicle model. The model is constructed and parametrized according to the specifications provided by the vehicle manufacturer. The simulation results conducted on different road surfaces, including dry, wet and icy, are introduced.", "author_names": [ "Andrei Aksjonov", "Valery Vodovozov", "Klaus Augsburg", "Eduard Petlenkov" ], "corpus_id": 117330837, "doc_id": "117330837", "n_citations": 27, "n_key_citations": 2, "score": 1, "title": "Design of Regenerative Anti Lock Braking System Controller for 4 In Wheel Motor Drive Electric Vehicle with Road Surface Estimation", "venue": "", "year": 2018 }, { "abstract": "", "author_names": [ "Yiming Zhao", "Junzhi Zhang", "Chao Ci Li", "Chengkun He" ], "corpus_id": 195444434, "doc_id": "195444434", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Sliding Mode Control Algorithm for Regenerative Braking of an Electric Bus with a Pneumatic Anti lock Braking System", "venue": "IOP Conference Series: Materials Science and Engineering", "year": 2019 }, { "abstract": "Anti lock Braking System ABS is a monitoring system aims at preventing locking of vehicle wheels during an emergency braking. When the brake pedal is intensely pressed, the vehicle wheels can be locked and as a result the steering capability will be very poor, the stopping distance may possibly be getting longer and the friction can significantly wear off the vehicle tires. A good Anti lock Braking System device can address these faults by unlocking the wheels. This paper proposes an efficient embedded computing component for anti Lock braking system with the intention of improving the contemporary Anti lock Braking Systems.", "author_names": [ "Yair Wiseman" ], "corpus_id": 53664244, "doc_id": "53664244", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Efficient Embedded Computing Component for Anti Lock Braking System", "venue": "", "year": 2018 }, { "abstract": "This paper deals with a novel method for integration of the active suspension system and the anti lock braking system. In the proposed method, a new nonlinear controller with state constraints is developed for the active suspension system based on the response prediction of 14 degree of freedom vehicle model. The proposed controller isolates the vehicle from road roughness in normal conditions and assists the anti lock braking system by ensuring a good contact between the tyre and road during hard braking. In addition, the tyre deflection is limited to prevent the threat of tyre bursting. To develop the active suspension system controller, at first, a performance index consisting of a weighted combination of predicted responses of suspension system is expanded as a function of current control input. At the same time, the state constraints of tyre normal force and tyre deflection are transformed to the equivalent constraints of control input by the same prediction approach. Then, the control law is found by minimizing the expanded performance index in the presence of input constraints. The Karush Kuhn Tucker theorem is employed to solve the performed constrained optimization problem analytically. The performance of the proposed active suspension system controller integrated with the designed nonlinear anti lock braking system controller is evaluated for a full vehicle model including roll and pitch motions during braking on irregular random roads. The results show that both the body acceleration and the vehicle stopping distance are decreased for the proposed integrated strategy compared with other conventional strategies.", "author_names": [ "Sajjad Aghasizade", "Mehdi Mirzaei", "Sadra Rafatnia" ], "corpus_id": 66992045, "doc_id": "66992045", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Novel constrained control of active suspension system integrated with anti lock braking system based on 14 degree of freedom vehicle model", "venue": "", "year": 2018 }, { "abstract": "Anti lock Braking System (ABS) is a system that automatically adjusts the braking force of the wheels when the vehicle is braking. It can prevent the wheels from locking to obtain the best braking effect, and improve the directional stability of the automobile. In the paper, the ABS system models based on Matlab were established, including single wheel vehicle model, tire model and vehicle braking system model. The Matlab/Simulink simulation environment was used to simulate the braking effect of a car with and without an ABS system by combining specific actual vehicle data. The simulation results confirm the validity and effectiveness of ABS. Introduction In recent years, cars production and ownership are increased rapidly, which brought a lot of harm to the society, such as traffic accidents [1] In order to improve the safety of the car, an Anti lock Braking System (ABS) is added to the conventional braking system. When the vehicle brakes, ABS automatically adjust wheel braking force of each wheel to prevent it from locking, so the braking system of automobiles can obtain the best braking effect, it is considered as one of the effective measures to enhance the driving safety of a car [2,3,4] A simulation algorithm based on Matlab is presented in the paper to confirm the validity and effectiveness of ABS. System Model Based on Matlab Vehicle Dynamics Model. Taking into account the computational complexity and simulation accuracy of the vehicle model, a classic single wheel model is used, which is shown as Fig.1[5] Fig.1. Single wheel vehicle model The required dynamic equations can be established for the two degrees of freedom of the vehicle body in the driving direction and the direction of the wheel around the main axis in the model, thus a simplified vehicle dynamic equation is obtained[5] The motion equation of the vehicle can be described as follows: F v M (1) The wheel dynamic equation can be shown as follows: 3rd International Conference on Automation, Mechanical Control and Computational Engineering (AMCCE 2018) Copyright (c) 2018, the Authors. Published by Atlantis Press. This is an open access article under the CC BY NC license (http:/creativecommons.org/licenses/by nc/4.0/ Advances in Engineering Research, volume 166", "author_names": [ "Fengping Cao", "Chunmei Chen", "Lifa Zhou" ], "corpus_id": 65125372, "doc_id": "65125372", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Research on Simulation of Anti lock Braking System Based on MATLAB", "venue": "", "year": 2018 }, { "abstract": "Bench inspection approach for automobile Anti lock Braking System (ABS) has gained research interests recently due to its high efficiency, small site occupation and insusceptibility to environment influences. The current work proposed a novel systematic bench inspection approach for ABS. In order to dynamically simulate various road adhesion coefficients, torque controllers are used for loading different torques to the drums. Furthermore, flywheels are adopted to simulate the translational inertia of the vehicle braking on road for compensating the inertial energy of ABS road experiment on the bench. The principal component analysis (PCA) is applied for accurate and efficient data analysis. The automatic evaluation of ABS is achieved by using the processed PCA data as an input to the back propagation (BP) neural network classifier. The experiments established that the new approach can accurately simulate various road braking conditions. It can be carried out for the inspection of ABS installed in the car.", "author_names": [ "Xiangmo Zhao", "Ruru Hao", "Zhou Zhou", "Amira S Ashour", "Nilanjan Dey" ], "corpus_id": 116663415, "doc_id": "116663415", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Novel Bench Based Inspection Approach for Automobile Anti Lock Braking System", "venue": "", "year": 2018 }, { "abstract": "The anti lock braking system (ABS) is an essential part in ensuring safe driving in vehicles. The Security of onboard safety systems is very important. In order to monitor the functions of ABS and avoid any malfunction, a model based methodology with respect to structural analysis is employed in this paper to achieve an efficient fault detection and identification (FDI) system design. The analysis involves five essential steps of SA applied to ABS, which includes critical faults analysis, fault modelling, fault detectability analysis and fault isolability analysis, Minimal Structural Over determined (MSO) sets selection, and MSO based residual design. In terms of the four faults in the ABS, they are evaluated to be detectable through performing a structural representation and making the Dulmage Mendelsohn decomposition with respect to the fault modelling, and then they are proved to be isolable based on the fault isolability matrix via SA. After that, four corresponding residuals are generated directly by a series of suggested equation combinations resulting from four MSO sets. The results generated by numerical simulations show that the proposed FDI system can detect and isolate all the injected faults, which is consistent with the theoretical analysis by SA, and also eventually validated by experimental testing on the vehicle (EcoCAR2) ABS.", "author_names": [ "Qi Chen", "Wenfeng Tian", "Wuwei Chen", "Qadeer Ahmed", "Yanming Wu" ], "corpus_id": 56480594, "doc_id": "56480594", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Model Based Fault Diagnosis of an Anti Lock Braking System via Structural Analysis", "venue": "Sensors", "year": 2018 } ]

[ { "abstract": "Part I Semiconductor Material Properties Chapter 1: The Crystal Structure of Solids Chapter 2: Introduction to Quantum Mechanics Chapter 3: Introduction to the Quantum Theory of Solids Chapter 4: The Semiconductor in Equilibrium Chapter 5: Carrier Transport Phenomena Chapter 6: Nonequilibrium Excess Carriers in Semiconductors Part II Fundamental Semiconductor Devices Chapter 7: The pn Junction Chapter 8: The pn Junction Diode Chapter 9: Metal Semiconductor and Semiconductor Heterojunctions Chapter 10: Fundamentals of the Metal Oxide Semiconductor Field Effect Transistor Chapter 11: Metal Oxide Semiconductor Field Effect Transistor: Additional Concepts Chapter 12: The Bipolar Transistor Chapter 13: The Junction Field Effect Transistor Part III Specialized Semiconductor Devices Chapter 14: Optical Devices Chapter 15: Semiconductor Microwave and Power Devices Appendix A: Selected List of Symbols Appendix B: System of Units, Conversion Factors, and General Constants Appendix C: The Periodic Table Appendix D: Unit of Energy The Electron Volt Appendix E: \"Derivation\" of Schrodinger's Wave Equation Appendix F: Effective Mass Concepts Appendix G: The Error Function Appendix H: Answers to Selected Problems", "author_names": [ "Donald A Neamen" ], "corpus_id": 16587922, "doc_id": "16587922", "n_citations": 492, "n_key_citations": 17, "score": 1, "title": "Semiconductor physics and devices basic principles", "venue": "", "year": 2012 }, { "abstract": "We study electromechanical fields near the interface between a circular piezoelectric semiconductor cylinder and another piezoelectric semiconductor in which it is embedded. The cylinder is p doped. The surrounding material is n doped. The phenomenological theory of piezoelectric semiconductors consisting of the equations of piezoelectricity and the conservation of charge for holes and electrons is used. The theory is linearized for small carrier concentration perturbations. An analytical solution is obtained, showing the formation of a PN junction near the interface. Various electromechanical fields associated with the junction are calculated. The effects of a few physical parameters are examined.", "author_names": [ "Yixun Luo", "Ruo-ran Cheng", "Chunli Zhang", "Weiqiu Chen", "Jiashi Yang" ], "corpus_id": 139124490, "doc_id": "139124490", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Electromechanical Fields Near a Circular PN Junction Between Two Piezoelectric Semiconductors", "venue": "", "year": 2018 }, { "abstract": "This chapter reviews some of the basics of semiconductor theory that are necessary for an understanding of the development of the device models which follows. Also reviewed is pn junction theory as its behavior is basic to the operation of transistors. The review is brief and covers only those topics which have direct relevance to MOS VLSI circuits. For more exhaustive treatments, the reader is referred to textbooks on the subject [1] [12]", "author_names": [ "Narain D Arora" ], "corpus_id": 59880059, "doc_id": "59880059", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Review of Basic Semiconductor and pn Junction Theory", "venue": "", "year": 1993 }, { "abstract": "A PN junction between two types of piezoelectric semiconductors (PSCs) is analyzed based on the fully coupled nonlinear equations of PSCs without any assumptions. A perturbation theory is employed to obtain the analytical solution of the considered nonlinear problem. A general solution to one dimensional problems for PSCs is represented by a sum of a series of perturbation solutions. Typical properties including the electromechanical fields, built in potential and the current voltage characteristics of the piezoelectric PN junction are investigated for conditions of mechanical loading combined with a bias. The results reveal that the simplified linear (i.e. first order perturbation) solution reported in the literature fails to describe the nonlinear characteristics, such as current voltage characteristics of the piezoelectric PN junction, although it can give the electromechanical fields as well as concentrations of the electrons and holes near the interface of the PN junction for small carrier concentration perturbations. The presented nonlinear solution is valid and corresponds closely with the numerical solutions based on the commercial software COMSOL.", "author_names": [ "MingKai Guo", "Yuan Li", "GuoShuai Qin", "Minghao Zhao" ], "corpus_id": 127680506, "doc_id": "127680506", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Nonlinear solutions of PN junctions of piezoelectric semiconductors", "venue": "Acta Mechanica", "year": 2019 }, { "abstract": "In this chapter, we present basic device physics, general characteristics, and operation principles of a p n junction diode. A p n junction diode is referred to as a minority carrier device since its current conduction is controlled by the minority carrier diffusion process (i.e. electrons in the p region and holes in the n region)", "author_names": [ "Jitendra yogi", "SurajBhan Singh", "Vishal Verma", "", "Deepak Kumar" ], "corpus_id": 217514919, "doc_id": "217514919", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Theory and Application of PN Junction Diode in Physics", "venue": "", "year": 2017 }, { "abstract": "At present, non equilibrium thermodynamics is an important theory and method for studying the phenomenon of small scales. In this work, by studying the temperature changes of PN junctions under different voltage conditions and doping concentrations, the micro scale semiconductor materials PN junctions in non equilibrium thermodynamics and thermal phenomena are researched. It is found that under the effect of lower voltage, the temperature of the PN junction will first decrease and then increase, and as the voltage increases, this phenomenon will gradually disappear. This shows that under certain voltage conditions, the phenomenon of unbalanced junction temperature of the PN junction exists, which will provide a huge impetus for the development of the reliability of solar cells, light emitting diodes, high frequency devices, sensors and measurement methods.", "author_names": [ "Chenshan Gao", "Shao-Gang Wang", "Chun-Jian Tan", "Xu Liu", "Quan Zhou", "Huaiyu Ye" ], "corpus_id": 221914962, "doc_id": "221914962", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Thermal Non Equilibrium Analysis on PN junction", "venue": "2020 21st International Conference on Electronic Packaging Technology (ICEPT)", "year": 2020 }, { "abstract": "We study the extension of a piezoelectric semiconductor (PS) fiber containing a PN junction, focusing on the effective polarization charges which are fundamental to piezotronics. A one dimensional model derived previously from the macroscopic theory of PSs is used for a linear theoretical and nonlinear numerical analysis by COMSOL. Both homogeneous and heterogeneous junctions are studied. In addition to the built in electric potential and field as well as I V curve, distributed effective polarization charge along the fiber and concentrated effective polarization charge on the junction interface are calculated and examined.", "author_names": [ "Ruo-ran Cheng", "Chun-li Zhang", "Wei-qiu Chen", "Jia-shi Yang" ], "corpus_id": 212635937, "doc_id": "212635937", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "On The Effective Polarization Charges In Theextension Of A Piezoelectric Semiconductor Fiber With A Pn Junction", "venue": "2019 14th Symposium on Piezoelectrcity, Acoustic Waves and Device Applications (SPAWDA)", "year": 2019 }, { "abstract": "In this paper, we have systematically investigated the temperature gradient dependent electrical behaviours in a piezoelectric PN junction. A new iterative computational method is proposed by utilizing the 1 D nonlinear theories of thermo piezoelectric semiconductors. Coupling between the thermal gradient fields and polarization charges is discussed. It is found that the electromechanical field of a piezoelectric PN junction has a quick response to thermal gradient. Furthermore, gate voltage and carrier transport characteristics can be effectively tuned with thermal induced and piezoelectric charges. It is shown that a piezoelectric PN junction is highly sensitive to the temperature gradient, which may provide an alternative approach to manipulate the carrier transport in piezotronic devices.", "author_names": [ "MingKai Guo", "Chunsheng Lu", "GuoShuai Qin", "M Zhao" ], "corpus_id": 231673476, "doc_id": "231673476", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Temperature Gradient Dominated Electrical Behaviours in a Piezoelectric PN Junction", "venue": "Journal of Electronic Materials", "year": 2021 }, { "abstract": "", "author_names": [], "corpus_id": 237672071, "doc_id": "237672071", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Universal Theory and Basic Rules of Strain Dependent Doping Behaviors in Semiconductors", "venue": "", "year": 2021 }, { "abstract": "Semiconductor pn junction is a two terminal device. It is the most fundamental device element that forms the basis of many electronic devices such as pn diodes, optoelectronic devices like light emitting diode and photodetector, field effect transistors and bipolar transistor. PN junction conducts high current in one direction and conduct very small amount of current in the reversed direction. Thus, pn junction has the property of rectification. PN junction is formed in a single crystal of semiconductor by making one end of the crystal p type by doping it with acceptor atom and making the other end n type by doping with donor atoms. The region where p type and n type meet is the junction. The equilibrium state is the state where the pn junction is left without any external stimulant such as electrical potential connected to it. This is also the state of zero bias voltage condition. When two semiconductor material type, p type and n type are brought to contact, majority carrier of each type would diffuse across the junction. This shall mean that the majority carrier hole from p type diffuses to n type material and the majority carrier of n type diffuses to p type material. The diffusion would stop after an electric field is built up sufficiently high to oppose diffusion. As the majority carrier such as hole diffuses across the junction, it combines with electron in the n type side, which creates a net positive charge. Likewise, the majority carrier electron from n type material diffuses across the junction recombines with hole in p type side creates net negative charge. The net charge at each side creates an electric field in the direction, which would oppose further diffusion. The electric field created would drift the minority carrier in the opposite direction across the junction. Thus when equilibrium attained, the drift carriers and diffused carriers should be balanced in termed of", "author_names": [], "corpus_id": 14758896, "doc_id": "14758896", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chapter 1 Semiconductor Pn Junction Theory and Applications _____________________________________________ 1.0 Introduction 1.1 Pn Junction at Equilibrium", "venue": "", "year": null } ]

[ { "abstract": "A two phase heat spreader has been developed for cooling high heat flux sources in high power lasers, high intensity light emitting diodes, and semiconductor power devices. The heat spreader targets the passive cooling of heat sources with fluxes greater than 5 W/mm2 without requiring any active power consumption for the thermal solution. The prototype vapor chamber consists of an evaporator plate, a condenser plate and an adiabatic section, with water as the phase change fluid. The custom designed high heat flux source is composed of a platinum resistive heating pattern and a temperature sensor on an aluminum nitride substrate which is soldered to the outside of the evaporator. Experiments were performed with several different microstructures as evaporator surfaces under varying heat loads. The first microstructure investigated, a screen mesh, dissipated 2 W/mm2 of heat load but with an unacceptably high evaporator temperature. A sintered copper powder microstructure with particles of 50 mm mean diameter supported 8.5 W/mm2 without dryout. Four sets of particle diameters and different thicknesses for the sintered copper powder evaporators were tested. Additionally, some of the sintered structures were coated with multi walled carbon nanotubes (CNT) that were rendered hydrophilic. Such nano structured evaporators successfully showed a further reduction in thermal resistance of the vapor chamber.Copyright (c) 2010 by ASME", "author_names": [ "Mitsuo Hashimoto", "Hiroto Kasai", "Kazuma Usami", "Hiroyuki Ryoson", "Kazuaki Yazawa", "Justin A Weibel", "Suresh V Garimella" ], "corpus_id": 18200509, "doc_id": "18200509", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "Nano Structured Two Phase Heat Spreader for Cooling Ultra High Heat Flux Sources", "venue": "", "year": 2010 }, { "abstract": "A new welding method, flux bands constricting arc (FBCA) welding, is proposed to compensate for the shortage of insufficient weld width of laser welding T joints in high steel sandwich panels. The arc behavior (arc burning position, arc shape, arc heat, and arc stability) before and after sticking the flux bands (GMAW and FBCA welding) to the ultra narrow gap groove was tested. Results indicate that flux bands have solid wall constricting effect (SWCE) and thermo compression effect (TCE) on the arc and self producing slag and gas function in FBCA welding. In ultra narrow gap groove, the arc burning position climbing up phenomenon (APCP) occurs without flux bands. The SWCE of flux bands on the arc effectively suppresses the APCP because of the insulation of flux bands. In the FBCA welding process, the effective heating area of the arc is increased by at least 5 mm2 compared with that in GMAW. When the groove gap decreases, flux bands not only compress the arc from an inverted bell shape to a rectangular shape, but also make the 660 degC isotherm on the core plate to increase from 3 mm to 8 mm. In the end, the proportion of unstable arc burning time is reduced by 86.85% the fluctuation of arc voltage and welding current are also significantly reduced by the flux bands because of their SWCE on the arc.", "author_names": [ "Lei Wang", "Ji Sen Qiao", "Jianhong Chen" ], "corpus_id": 215409800, "doc_id": "215409800", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Mechanism of Effect of Flux Bands on The Arc Behavior in Flux Bands Constricting Arc Welding Process", "venue": "Materials", "year": 2020 }, { "abstract": "The Pierre Auger Observatory is the most sensitive air shower detector for primary photons with energies above \\sim 0.2$ EeV. Using the Surface Detector array (SD) photons in the zenith angle range from 30$\\circ$ to 60$\\circ$ can be identified through the broad time structure of the signals expected to be induced in the SD stations. An additional signature for photon induced air showers is the steeper lateral distribution of secondary particles at the ground with respect to nucleonic showers. Stringent limits are set to the diffuse flux of ultra high energy (UHE) photons above 10 EeV, using SD data collected between 2004 and mid 2018 with an exposure of $40\\,000$ km$^2\\$sr$$yr. Below 1 EeV, unprecedented separation power between primary photons and hadrons can be achieved by combining observables from the low energy enhancements of the Pierre Auger Observatory, namely three upwards pointing fluorescence telescopes, which can directly measure the atmospheric depth of the shower maximum, and the 750 m SD array, which again accesses the steeper lateral distribution of photon induced air showers. For the first time, limits on the integral photon flux below 1 EeV are presented using data collected by the Pierre Auger Observatory between mid 2010 and 2015. This extends the range of photon searches at the Pierre Auger Observatory to about three decades in energy.", "author_names": [ "Julian Rautenberg" ], "corpus_id": 199674566, "doc_id": "199674566", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Limits on ultra high energy photons with the Pierre Auger Observatory", "venue": "Proceedings of 36th International Cosmic Ray Conference PoS(ICRC2019)", "year": 2019 }, { "abstract": "Efficient RNA extraction methods are needed to study transcript regulation. Such methods must lyse the cell without degrading the genetic material. For cyanobacteria this can be particularly challenging because of the presence of the cyanobacteria cell envelope. The great breath of cyanobacterial shape and size (unicellular, colonial, or filamentous multicellular) created a variety of cell lysis methods. However, there is still a lack of reliable techniques for nucleic acid extraction for several types of cyanobacteria. Here we designed and tested 15 extraction methods using physical, thermic or chemical stress on the filamentous cyanobacteria Planktothrix agardhii. Techniques based on the use of beads, sonication, and heat shock appeared to be too soft to break the Planktothrix agardhii cell envelope, whereas techniques based on the use of detergents degraded the cell envelope but also the RNA. Two protocols allowed to successfully obtain good quality RNA. The first protocol consisted to manually crush the frozen cell pellet with a pestle and the second was based on the use of high intensity ultra sonication. When comparing these two, the high intensity ultra sonication protocol was less laborious, faster and allowed to extract 3.5 times more RNA compared to the liquid nitrogen pestle protocol. The high intensity ultra sonication protocol was then tested on five Planktothrix strains, this protocol allowed to obtain >8.5 mg of RNA for approximatively 3.5 x 108 cells. The extracted RNA were characterized by 260/280 and 260/230 ratio to 2, indicating that the samples were devoid of contaminant, and RNA Quality Number to 7, meaning that the integrity of RNA was preserved with this extraction method. In conclusion, the method we developed based on high intensity ultra sonication proved its efficacy in the extraction of Planktothrix RNA and could be helpful for other types of samples.", "author_names": [ "Sandra Kim Tiam", "Katia Comte", "Caroline Dalle", "Charlotte Duval", "Claire Pancrace", "Muriel Gugger", "Benjamin Marie", "Claude Yepremian", "Cecile Bernard" ], "corpus_id": 201868775, "doc_id": "201868775", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Development of a new extraction method based on high intensity ultra sonication to study RNA regulation of the filamentous cyanobacteria Planktothrix", "venue": "PloS one", "year": 2019 }, { "abstract": "We experimentally study high pressure pool boiling heat transfer enhancement using a copper sintered particle wick structure in water. The wicks are fabricated using the multi step sintering process using 200 mm sintered copper powder. Thermophysical properties of water change at elevated pressure, therefore changing the bubble dynamics. For the single layer wick, Critical Heat Fluxes (CHF) of 179.63, 182.42, and 198.16 W/cm2 are found at 0, 103.4, and 206.8 kPa, respectively. The maximum CHF is found at 206.8 kPa with the wick superheat of 9.9 K. A 110% enhancement is found in the CHF for 206.8 kPa, compared to 0 kPa. We observed a CHF 1.8 times higher compared to the plain surface at 0 kPa. The maximum Heat Transfer Coefficient (HTC) of 252.46 W/cm2 K is found at a heat flux of 100 W/cm2 and a pressure of 206.8 kPa. The high pressure pool boiling result for the single layer wick shows that the heat transfer coefficient is enhanced by 100% compared to 0 kPa. We suggest the reasons for enhancement of the pool boiling performance is primarily due to high rate of bubble generation, high bubble release frequency, and reduced thermal hydraulic length modulation, and enhanced thermal conductivity due to the sintered wick layer. Our analysis suggests that the Rayleigh critical wavelength decreases by 4.67% with varying pressure, which may cause the bubble pinning between the sintered particles and prevents bubble coalescence. Similarly, the role of pressure in enhancing heat transfer compared to the effect of the wicking layer is also analyzed and found that the critical flow length, lu reduces by three times for 200 mm diameter particles. We suggest that the porous wick layer provides a capillary assist to liquid flow effect, and delays the surface dry out. The pressure and surface modification amplify the boiling heat transfer performance. All these reasons may contribute to the CHF and HTC enhancement in the wicking layer at high pressure.", "author_names": [ "Smreeti Dahariya", "Nill Patel", "Munonyedi Kelvin Egbo", "Gisuk Hwang", "Amy Rachel Betz" ], "corpus_id": 210840277, "doc_id": "210840277", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "High Pressure Pool Boiling Heat Transfer Enhancement Mechanism on Sintered Particle Wick Surface", "venue": "Frontiers in Mechanical Engineering", "year": 2019 }, { "abstract": "Recently, the use of electrical vehicles has abruptly increased due to environmental crises. The high energy density of lithium ion batteries is their main advantage for use in electric vehicles (EVs) However, the thermal management of Li ion batteries is a challenge due to the poor heat resistance of Lithium ions. The performance and lifetime of lithium ion batteries are strongly affected by the internal operating temperature. Thermal characterization of battery cells is very important to ensure the consistent operation of a Li ion battery for its application. In the present study, the OHP (Oscillating Heat Pipe) system is proposed as a battery cooling module, and experimental verification was carried out. OHP is characterized by a long evaporator section, an extremely short condenser section, and almost no adiabatic section. Experimental investigations were conducted using various parameters such as the filling ratio, orientation, coolant temperature, and heat flux. Average temperature of the heater's surface was maintained at 56.4 degC using 14 W with 25 degC coolant water. The experimental results show that the present cooling technology basically meets the design goal of consistent operation.", "author_names": [ "Ri-Guang Chi", "Seok-Ho Rhi" ], "corpus_id": 155774379, "doc_id": "155774379", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Oscillating Heat Pipe Cooling System of Electric Vehicle's Li Ion Batteries with Direct Contact Bottom Cooling Mode", "venue": "Energies", "year": 2019 }, { "abstract": "Process temperature is an important process parameter for hot rolled strips, directly affecting microstructure and property. Recently, ultra fast cooling (UFC) technology is widely used in development and production of hot rolled strips, because of its high cooling rate, which can reduce alloy element and improve microstructure and property.1,2) In order to get ideal microstructure of hot rolled strips, UFC and laminar cooling on run out table are jointly utilized to cool hot strips from FDT (Finishing Delivery Temperature) down to UFC T (UFC delivery temperature) and CT (coil temperature) by setting process path. In addition, UFC can be used individually, by which cools strip to UFC T, and then to CT in air condition. Therefore, precisely and highly flexible control of UFC T and CT in cooling section is extremely important. To achieve precise control of UFC T and CT on run out table, many models and strategies are adopted. Physical model can achieve accuracy temperature control by describing heat transfer process. But for convenience industrial applications, the physical model is usually simplified.3,4) Statistical models have been developed to solve the situation that closely reflects reality as much accurately as possible.5) And there are also many artificial intelligence algorithm models,6 10) such as fuzzy control model, neural network model and instant base learning by k NN algorithm are utiResearch and Application of Model and Control Strategies for Hot Rolled Strip Cooling Process Based on Ultra Fast Cooling System", "author_names": [ "Zhen-lei Li", "Yun-jie Li", "G Yuan" ], "corpus_id": 204295534, "doc_id": "204295534", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Research and Application of Model and Control Strategies for Hot Rolled Strip Cooling Process Based on Ultra Fast Cooling System", "venue": "", "year": 2020 }, { "abstract": "Abstract. We investigated the interactions between the air pollutants and the structure of the urban boundary layer (UBL) over Beijing by using the data mainly obtained from the 325 m meteorological tower and a Doppler wind lidar during 1 4 December 2016. Results showed that the pollution episodes in this period could be characterized by low surface pressure, high relative humidity, weak wind, and temperature inversion. Compared with a clean daytime episode that took place on 1 December, results also showed that the attenuation ratio of downward shortwave radiation was about 5 24 and 63 in afternoon hours (from 12:00 to 14:00 local standard time, LST) on 2 4 December, respectively, while for the net radiation (Rn) attenuation ratio at the 140 m level of the 325 m tower was 3 27 and 68 The large reduction in Rn on 4 December was not only the result of the aerosols, but also clouds. Based on analysis of the surface energy balance at the 140 m level, we found that the sensible heat flux was remarkably diminished during daytime on polluted days and even negative after sunrise (about 07:20 LST) till 14:00 LST on 4 December. We also found that heat storage in the urban surface layer played an important role in the exchange of the sensible heat flux. Owing to the advantages of the wind lidar having superior spatial and temporal resolution, the vertical velocity variance could capture the evolution of the UBL well. It clearly showed that vertical mixing was negatively related to the concentrating of pollutants, and that vertical mixing would also be weakened by a certain quantity of pollutants, and then in turn worsened the pollution further. Compared to the clean daytime on 1 December, the maximums of the boundary layer height (BLH) decreased about 44 and 56 on 2 3 December, when the average PM2.5 (PM1) concentrations in afternoon hours (from 12:00 to 14:00 LST) were 44 (48) ug m 3 and 150 (120) ug m 3. Part of these reductions of the BLH was also contributed by the effect of the heat storage in the urban canopy.", "author_names": [ "Linlin Wang", "Junkai Liu", "Zhiqiu Gao", "Yubin Li", "Meng Huang", "Sihui Fan", "Xiaoye Zhang", "Yuanjian Yang", "Shiguang Miao", "Han Zou", "Yele Sun", "Yong Chen", "Ting Yang" ], "corpus_id": 196901610, "doc_id": "196901610", "n_citations": 32, "n_key_citations": 1, "score": 0, "title": "Vertical observations of the atmospheric boundary layer structure over Beijing urban area during air pollution episodes", "venue": "Atmospheric Chemistry and Physics", "year": 2019 }, { "abstract": "Thermal interface materials (TIMs) used for bonding components are important for creating a thermally conductive path which improves heat dissipation. Low density, porous carbon foams are commonly used for thermal management applications and devices. Their high surface area to volume ratio enables cooling more effectively via different heat transfer methods. Many studies have adopted different methods to analytically or computationally analyze the effective thermal conductivity of carbon foams. Others have studied the participation of TIMs used in composite materials. However, very few studies have analyzed the microscale effects in heat transfer of the interaction between TIM and carbon foams. The amount of contact between a carbon foam and a bonded surface has hardly been reported in the literature. In this study, the carbon foam is deposited with thin layers of graphene until reaching the desired foam density; this type of foam is known as the graphitic foam. Graphene's highly anisotropic thermal properties result in high thermal conductivity in the planar direction but low in the normal direction. With these anisotropic thermal characteristics, the objective of this study is to determine the effect of TIM thickness on thermal conductivity of the graphitic foam. It was hypothesized that the direction which heat enters the graphitic foam and the size of the cross sectional area normal to the heat flux direction would affect the overall effective thermal conductivity. As commonly known, a gap created between ligands (foam structure) and the bonded surface would likely reduce the overall effective thermal conductivity. At the gap, heat is transferred via the TIMs or the graphitic foam through conduction, depending on if a direct contact exists between the graphitic foam and the bonded surface. The filler types used for the TIMs are hypothesized to play a critical role in the heat portion transferred via the TIMs. The heat transfer in 2 D becomes extremely complicated while anisotropic materials (graphene coating) and isotropic materials (TIMs) interact. Furthermore, the non uniform structure of the carbon foam introduces more complexity to the heat transfer at the interface. A computational model using ANSYS finite element program was developed in this study to help the analysis. The results demonstrate that the parameters at the interface can be optimized to improve the overall effective thermal conductivity of the interface.", "author_names": [ "Fangbing Lin", "Eric C Anderssen", "Raymond K Yee" ], "corpus_id": 212658407, "doc_id": "212658407", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Heat Transfer Interface to Graphitic Foam", "venue": "Volume 8: Heat Transfer and Thermal Engineering", "year": 2019 }, { "abstract": "Nucleate boiling is an efficient heat transfer mechanism that enables the dissipation of high heat fluxes at low temperature differences. Heat transfer phenomena during nucleate boiling are closely linked to the two phase flow morphology that evolves in time and based on the operating conditions. In particular, the critical heat flux, which is the upper limit for the nucleate boiling regime, can be triggered by hydrodynamic mechanisms resulting from interactions between the liquid and vapor phases. The aim of this thesis is to characterize the two phase flow morphology evolution during nucleate boiling at high heat fluxes in two configurations: pool boiling, and confined and submerged two phase jet impingement. The characterization is performed via non invasive, high speed optical based diagnostic tools. Experimental characterization of liquid vapor interfaces during boiling is often challenging because the rapidly evolving vapor structures are sensitive to invasive probes and multiple interfaces can occlude one another along a line of sight. In this thesis, a liquid vapor interface reconstruction technique based on high speed stereo imaging is developed. Images are filtered for feature enhancement and template matching is used for determining the correspondence of local features of the liquid vapor interfaces between the two camera views. A sampling grid is overlaid on the reference image and windows centered at each sampled pixel are compared with windows centered along the epipolar line in the target image to obtain a correlation signal. To enhance the signatures of true matches, the correlation signals for each sampled pixel are averaged over a short time ensemble correlation. The three dimensional coordinates of each matched pixel are determined via triangulation, which yields a set of points in the physical world representing the liquid vapor interface. The developed liquid vapor interface reconstruction technique is a high speed, flexible and non invasive alternative to the various existing methods for phase distribution mapping. This technique also has the potential to be combined with other optical based diagnostic tools, such as tomographic particle image velocimetry, to further understand the phase interactions.The liquid vapor interface reconstruction technique is used to characterize liquid vapor interfaces above the heated surface during nucleate pool boiling, where the textured interface resulting from the boiling phenomena and flow interactions near the heated surface is particularly suited for reconstruction. Application of the reconstruction technique to pool boiling at high heat fluxes produces a unique quantitative characterization of the liquid vapor interface morphology near heated surface. Analysis of temporal signals extracted from reconstructions indicate a clear transition in the nature of the vapor flow dynamics from a plume like vapor flow to a release mode dominated by vapor burst events. Further investigation of the vapor burst events allows identification of a characteristic morphology of the vapor structures that form above the surface that is associated to the square shape of the heat source. Vapor flow morphology characterization during pool boiling at high heat fluxes can be used to inform vapor removal strategies that delay the occurrence of the critical heat flux during pool boiling.As compared to pool boiling, nucleate boiling can be sustained up to significantly higher heat fluxes during two phase jet impingement. The increases in critical heat flux are explained via hydrodynamic mechanisms that have been debated in the literature. The connection between two phase flow morphology and the extension of nucleate boiling regime is investigated for a single subcooled jet of water that impinges on a circular heat source via high speed visualization from two synchronized top and side views of the confinement gap. When boiling occurs under subcooled exit flow conditions and at moderate heat fluxes, the regular formation and collapse of vapor structures that bridge the heated surface and the orifice plate is observed, which causes significant oscillations in the pressure drop across. Under saturated exit flow conditions, the vapor agglomerates in the confinement gap into a bowl like vapor structure that recurrently shrinks, due to vapor break off at the edge of the orifice plate, and replenishes due to vapor generation. The optical visualizations from the top of the confinement gap provide a unique perspective and indicate that the liquid jet flows downwards through the vapor structure, impinges on the heated surface, and then flows underneath the vapor structure, as a fluid wall jet the keeps the heated surface wetted such that discrete bubbles continue to nucleate. At high heat fluxes, intense vapor generation causes the fluid wall jet to transition from a bubbly to a churn like regime, and some liquid droplets are sheared off into the vapor structure. The origin of critical heat flux appears to result from a significant portion of the liquid in the wall jet being deflected off the surface, and the remaining liquid film on the surface drying out before reaching the edge of the heater.The flow morphology characterizations presented in this dissertation further the understanding of flow and heat transfer phenomena during nucleate boiling. In the pool boiling configuration, the vapor release process was quantitatively described; during two phase jet impingement, a possible mechanism for critical heat flux was identified. Opportunities for future work include the utilization of image processing techniques to extract quantitative measurements from two phase jet impingement visualizations. Also, the developed liquid vapor interface reconstruction technique can be applied to a boiling situation with a simpler liquid vapor interface geometry, such as film boiling, to generate benchmark data for validation and development of numerical models.", "author_names": [ "C Hernandez" ], "corpus_id": 199176404, "doc_id": "199176404", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Characterization of Two Phase Flow Morphology Evolution during Boiling via High Speed Visualization", "venue": "", "year": 2019 } ]

[ { "abstract": "The USB Revolution Robotic vision is the most fascinating and feasible application for neuromorphic engineering, since processing images in real time with low power consumption is the field's most critical requirement. Conventional machine vision systems have been implemented using CMOS (complimentary metal oxide semiconductor) imagers or CCD (charge coupled device) cameras that are interfaced to digital processing systems operating with serial algorithms. These systems often consume too much power, are too large, and compute with too high a cost.1 Though neuromorphic technology has advantages in these areas, there are some disadvantages too: current implementations have less programmable architectures, for example, than digital processing technologies. In addition, digital image processing has a long history and highly developed hardware and software for pattern recognition are readily available. We therefore think it is practical at least at the current stage of progress in neuromorphic engineering to combine neuromorphic sensors with conventional digital technology to implement, for robot vision, the computational essence of what the brain does. On this basis, we designed a neuromorphic vision system consisting of analog VLSI (very large silicon integration) neuromorphic chips and field programmable gate array (FPGA) circuits. Figure 1 shows a block diagram of the system, which consists of silicon retinas, 'simple cell' chips (named after the simple cell in the V1 area of the brain) and FPGA circuits. The silicon retina is implemented with active pixel sensors (conventionallysampled photo sensors)2 and has a concentric center surround Laplacian Gaussian like receptive field.2 Its output image is transferred to the simple cell chips serially. These chips then aggregate analog pixel outputs from the silicon retina to generate an orientation selective response similar to the simple cell response in the primary visual cortex.3 The architecture mimics the feed forward model proposed by Hubel and Wiesel,4 and efficiently computes the two dimensional Gabor like receptive field using the concentric center surround receptive field. The signal transfer from the silicon retina to the simple cell chip is performed using analog voltage, aided by analog memories embedded in each pixel of the simple cell chip. The output image of the simple cell chip is then converted into a digital signal and fed into the FPGA circuits, where the image is further processed with programReceptive field Silicon retina", "author_names": [ "Misha A Mahowald", "Carver Mead" ], "corpus_id": 5126325, "doc_id": "5126325", "n_citations": 189, "n_key_citations": 4, "score": 1, "title": "The silicon retina.", "venue": "Scientific American", "year": 1991 }, { "abstract": "A new rotation invariant pattern recognition system is proposed and analyzed. In this system, silicon retina cells capable of image sensing and edge extraction are used so that the system can directly process images from the real world without an extra edge detector. The rotation invariant discrete correlation function is modified and implemented in the silicon retina structure by using the current summation. Simulation results have verified the correct function of the proposed system. Moreover, an experimental chip to implement the proposed system with a 32/spl times/32 cell array has been designed and fabricated in 0.8 /spl mu/m n well CMOS process. Experimental results have successfully shown that the system works well for the arbitrary orientation pattern recognition.", "author_names": [ "Chin-Fong Chiu", "Chung-Yu Wu" ], "corpus_id": 54606077, "doc_id": "54606077", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "The design of rotation invariant pattern recognition using the silicon retina", "venue": "", "year": 1997 }, { "abstract": "In this paper a new stereo matching concept for event driven silicon retinae is presented. The main contribution of the proposed approach is the correlation of incoming events. As a novelty, not only the spatial information is used, but also the time of occurrence of the events as a part of the similarity measure. Stereo matching is used in depth generating camera systems for solving the correspondence problem and for 3D reconstruction of the sensed environment. In fact, using conventionally frame based cameras, this is a time consuming and computationally expensive task, especially for high frame rates and spatial resolutions. An event based silicon retina delivers events only on illumination changes and completely asynchronous in time. The sensor provides no frames, but a time continuous data stream of intensity differences and thus inherently reduces the visual information to a minimum. This paper focuses on an event based stereo matching algorithm implemented in hardware on a field programmable gate array (FPGA) that allows a reliable matching of the sparse input event data. Furthermore, the approach is compared to other standard frame based and event driven stereo methods. The results show that the achieved depth map outperforms other algorithms in terms of accuracy and the calculation performance of the hardware architecture is in the range or still higher than state of the art computing platforms.", "author_names": [ "Florian Eibensteiner", "Hans Georg Brachtendorf", "Josef Scharinger" ], "corpus_id": 37664826, "doc_id": "37664826", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Event driven stereo vision algorithm based on silicon retina sensors", "venue": "2017 27th International Conference Radioelektronika (RADIOELEKTRONIKA)", "year": 2017 }, { "abstract": "In this paper, we present: (i) a novel analog silicon retina featuring auto adaptive pixels that obey the Michaelis Menten law, i.e. V=V(m) I(n)/I(n)+s(n) (ii) a method of characterizing silicon retinas, which makes it possible to accurately assess the pixels' response to transient luminous changes in a 3 decade range, as well as changes in the initial steady state intensity in a 7 decade range. The novel pixel, called M(2)APix, which stands for Michaelis Menten Auto Adaptive Pixel, can auto adapt in a 7 decade range and responds appropriately to step changes up to 3 decades in size without causing any saturation of the Very Large Scale Integration (VLSI) transistors. Thanks to the intrinsic properties of the Michaelis Menten equation, the pixel output always remains within a constant limited voltage range. The range of the Analog to Digital Converter (ADC) was therefore adjusted so as to obtain a Least Significant Bit (LSB) voltage of 2.35mV and an effective resolution of about 9 bits. The results presented here show that the M(2)APix produced a quasi linear contrast response once it had adapted to the average luminosity. Differently to what occurs in its biological counterparts, neither the sensitivity to changes in light nor the contrast response of the M(2)APix depend on the mean luminosity (i.e. the ambient lighting conditions) Lastly, a full comparison between the M(2)APix and the Delbruck auto adaptive pixel is provided.", "author_names": [ "Stefano Mafrica", "Stephanie Godiot", "Mohsine Menouni", "Marc Boyron", "Fabien Expert", "Raphael Juston", "Nicolas Marchand", "Franck Ruffier", "Stephane Viollet" ], "corpus_id": 19608231, "doc_id": "19608231", "n_citations": 17, "n_key_citations": 4, "score": 0, "title": "A bio inspired analog silicon retina with Michaelis Menten auto adaptive pixels sensitive to small and large changes in light.", "venue": "Optics express", "year": 2015 }, { "abstract": "A new silicon retina structure in CMOS is proposed and analyzed, which incorporates a parasitic phototransistor as an isolated photoreceptor with many phototransistors in a common well region. The smooth function is achieved by the diffusion of photogenerated carriers in the common well. Experimental results have verified the correct functions of the new structure as a silicon retina. Small chip area and compact wiring make the new structure quite realizable with the associated neural networks in VLSI.<ETX>", "author_names": [ "Chung-Yu Wu", "Chin-Fong Chiu" ], "corpus_id": 114546204, "doc_id": "114546204", "n_citations": 9, "n_key_citations": 2, "score": 0, "title": "A new structure for the silicon retina", "venue": "1992 International Technical Digest on Electron Devices Meeting", "year": 1992 }, { "abstract": "Optical flow sensors have been a long running theme in neuromorphic vision sensors which include circuits that implement the local background intensity adaptation mechanism seen in biological retinas. This paper reports a bio inspired optical motion sensor aimed towards miniature robotic and aerial platforms. It combines a 20 x 20 continuous time CMOS silicon retina vision sensor with a DSP microcontroller. The retina sensor has pixels that have local gain control and adapt to background lighting. The system allows the user to validate various motion algorithms without building dedicated custom solutions. Measurements are presented to show that the system can compute global 2D translational motion from complex natural scenes using one particular algorithm: the image interpolation algorithm (I2A) With this algorithm, the system can compute global translational motion vectors at a sample rate of 1 kHz, for speeds up to 1000 pixels/s, using less than 5 k instruction cycles (12 instructions per pixel) per frame. At 1 kHz sample rate the DSP is 12% occupied with motion computation. The sensor is implemented as a 6 g PCB consuming 170 mW of power.", "author_names": [ "Shih-Chii Liu", "Minhao Yang", "Andreas Steiner", "Rico Moeckel", "Tobi Delbruck" ], "corpus_id": 30023786, "doc_id": "30023786", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "1 kHz 2D Visual Motion Sensor Using 20$\\times\\$20 Silicon Retina Optical Sensor and DSP Microcontroller", "venue": "IEEE Transactions on Biomedical Circuits and Systems", "year": 2015 }, { "abstract": "Abstract In the Background section of the proposal I described the basic conceptual elements which underlie the Silicon Retina (SR) and those which underlie passive mammalian hearing. My original intention was to utilize the frequency discrimination capability manifested in mammalian hearing as the mechanism on which to base an acoustic analogue to the SR concept. Specifically, mammals have sophisticated frequency dependent sensors which transmit responses to discrete and well resolved frequencies upward to higher processing levels. Each intermediate processor transmits the precise frequency information upstream. Thus one may think of acoustic frequencies as being analogous to visual positional information, since in the ray limit of optics there is a one to one correspondence between the relative locations of external objects and the retinal sensors which are stimulated at any given time. The SR mechanism was to be implemented by comparing individual frequencies with running averages over groups of nearby frequencies, eliciting a response when the intensities of these differed by a prescribed amount. The next step in the program was to remain open minded regarding the implementation of directional acoustic arrays, with the idea pf steering an array making use of the 'alert' response created by the introduction of a non background signal. In this way it was envisioned that the 'cocktail party effect' would be achieved.", "author_names": [ "Jorge F Willemsen" ], "corpus_id": 109386826, "doc_id": "109386826", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Feasibility Assessment of a Transient Sound Sensor Based on the Silicon Retina Architecture", "venue": "", "year": 1992 }, { "abstract": "In this paper we present a new approach for the evaluation of event based Silicon Retina stereo matching results. The evaluation of stereo matching algorithm results is a necessary task for the development, comparison, and improvement of depth generating camera systems. In contrast to conventional frame based cameras, the silicon retina sensors delivers asynchronous events instead of synchronous intensity or color images. The polarity of the events represents either an increase (on event) or a decrease (off event) of the brightness of the projected scene point. This is the reason why existing ground truth data and evaluation platforms are not suitable for testing silicon retina stereo camera systems. For the analysis of the introduced novel evaluation method, we use an area based (sum of absolute difference) algorithm for the event driven sensor system. A conventional video camera stereo vision system is used to produce reference data. The results show that the presented method offers new opportunities for the evaluation of stereo matching results computed from silicon retina stereo data.", "author_names": [ "Jurgen Kogler", "Florian Eibensteiner", "M Humenberger", "Margrit Gelautz", "Josef Scharinger" ], "corpus_id": 6258804, "doc_id": "6258804", "n_citations": 9, "n_key_citations": 2, "score": 0, "title": "Ground Truth Evaluation for Event Based Silicon Retina Stereo Data", "venue": "2013 IEEE Conference on Computer Vision and Pattern Recognition Workshops", "year": 2013 }, { "abstract": "Silicon retina, modeling a biological architecture, can implement parallel operations with low power. To implement a compact, fast image processing system, this paper describes a circuit with FPGA (field programmable gate array) and silicon retina combined together. Circuit optimization by DCT (discrete cosine transform) is proposed.", "author_names": [ "Motoki Amagasaki", "Fuminori Kobayashi", "Minoru Watanabe", "Tetsuya Yagi" ], "corpus_id": 63061574, "doc_id": "63061574", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Motion image compression circuit using the silicon retina as active sensor", "venue": "Proceedings of the 41st SICE Annual Conference. SICE 2002.", "year": 2002 }, { "abstract": "Abstract. We present two improvement techniques for stereo matching algorithms using silicon retina sensors. We verify the results with ground truth data. In contrast to conventional monochrome/color cameras, silicon retina sensors deliver an asynchronous flow of events instead of common framed and discrete intensity or color images. While using this kind of sensor in a stereo setup to enable new fields of applications, it also introduces new challenges in terms of stereo image analysis. Using this type of sensor, stereo matching algorithms have to deal with sparse event data, thus, less information. This affects the quality of the achievable disparity results and renders improving the stereo matching algorithms a necessary task. For this reason, we introduce two techniques for increasing the accuracy of silicon retina stereo results, in the sense that the average distance error is reduced. The first method is an adapted belief propagation approach optimizing the initial matching cost volume, and the second is an innovative two stage postfilter for smoothing and outlier rejection. The evaluation shows that the proposed techniques increase the accuracy of the stereo matching and constitute a useful extension for using silicon retina sensors for depth estimation.", "author_names": [ "Jurgen Kogler", "Florian Eibensteiner", "M Humenberger", "Christoph Sulzbachner", "Margrit Gelautz", "Josef Scharinger" ], "corpus_id": 29905418, "doc_id": "29905418", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Enhancement of sparse silicon retina based stereo matching using belief propagation and two stage postfiltering", "venue": "J. Electronic Imaging", "year": 2014 } ]

[ { "abstract": "In this work, we report the formation of porous unintentionally doped (UID) n type GaN films under a novel alternating current (sine wave a.c. (50 Hz) photo assisted electrochemical etching (ACPEC) conditions. The formation of porous unintentionally doped (UID) n type GaN by the novel ACPEC is performed in the same electrolyte concentration (4% KOH) used in common dc constant current electrochemical etching process. Ultra violet (UV) illumination is used to assist in the generation of electron hole pairs, where etching proceeds through the oxidation and consequently, dissolution of the semiconductor surface. The ac formed UID porous GaN with excellent structural and optical properties. According to the FESEM micrographs, the GaN thin films exhibit a homogeneous nanoarchitecture of the porous structures with perfect hexagonal shape. The porous layer exhibited a substantial photoluminescence (PL) intensity enhancement with red shifted band edge PL peaks associated with the relaxation of compressive stress. The shift of E2(high) to the lower frequency in Raman spectra of the UID porous GaN films further confirms such a stress relaxation. Electrical characterizations of the MSM photodiodes were carried out by using current voltage (I V) measurements indicated that the devices were highly sensitive to ambient light", "author_names": [ "Ainorkhilah Mahmood", "Zainuriah Hassan", "Alhan Farhanah Abd Rahim", "Rosfariza Radzali", "Naser M Ahmed", "Yushamdan Yusof", "Mohd Haris Ridzuan Ooi Abdullah", "Mohd Firdaus Roslan", "Mohd Nadeem Bukhari", "Sharifah Nooraishah Syed Mohd Zainol", "", "Zaki Mohd Yusoff", "Muhammad Firdaus Othman", "Surani Buniran", "Mohd Firdaus Roslee", "Norha Abdul Hadi", "Madhiyah Yahya", "Siti Hajar Mohmad Salleh", "Masbudi bin Baharuddin", "Vicinisvarri Inderan", "Kumar Sudesh" ], "corpus_id": 207799286, "doc_id": "207799286", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ENHANCING PERFORMANCE OF POROUS UNINTENTIONALLY DOPED GAN BASED MSM PHOTODETECTOR USING ALTERNATING CURRENT PHOTO ASSISTED ELECTROCHEMICAL ETCHING ACPEC TECHNIQUE", "venue": "", "year": 2019 }, { "abstract": "The present research reports the fabrication and performance evaluation of an AlGaN/GaN based metal semiconductor metal (MSM) ultraviolet (UV) photo detector on silicon (111) substrate. The MSM device has been fabricated with aluminium (Al) in an inter digitized (IDE) geometry on the molecular beam epitaxially grown epilayer. Substantially high photo current as 9.5 mA has been resulted under the illumination of 365 nm wavelength UV as compared to the dark current of 409mA with photo to dark current ratio of 23.22 and very high responsivity of 15798 A/W. Rise time as 1.01 seconds and fall time as 5.17 seconds has been observed after transient analysis of the devices. High carrier concentrations at the heterojunction due to polarization has been attributed for relatively larger photo current as compared to previous literature.", "author_names": [ "Indu Kumari", "Subhashis Das", "Ankush Bag" ], "corpus_id": 57191063, "doc_id": "57191063", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Selective UV Detection by AlGaN/GaN Based MSM Photo Detector for Integration with Silicon", "venue": "2018 IEEE SENSORS", "year": 2018 }, { "abstract": "Organic molecular monolayers (MoLs) have been used for improving the performance of various electronic device structures. In this work, the concept of organic molecular surface modification is applied for improving the performance of GaN based metal semiconductor metal (MSM) ultraviolet (UV) photodetectors (PDs) Organic molecules of phenol functionalized metallated porphyrin (hydroxyl phenyl zinc tetra phenyl porphyrin (Zn TPPOH) were adsorbed on GaN, and Ni/Zn TPPOH/GaN/Zn TPPOH/Ni PD structures were fabricated. This process was beneficial in two ways: first, the reverse bias dark current was reduced by 1000 times, and second, the photocurrent was enhanced by ~100 times, in comparison to the dark and photocurrent values obtained for Ni/GaN/Ni MSM PDs, at high voltages of 10 V. The responsivity of the devices was increased from 0.22 to 4.14 kA/W at 5 mW/cm2 optical power density at 10 V bias and at other voltages also. In addition to this, other PD parameters such as photo to dark current ratio and UV to visible rejection ratio were also enhanced. The spectral selectivity of the PDs was improved, which means that the molecularly modified devices became more responsive to UV spectral region and less responsive to visible spectral region, in comparison to bare GaN based devices. Photoluminescence measurements, power dependent photocurrent characteristics, and time resolved photocurrent measurements revealed that the MoL was passivating the defect related states on GaN. In addition, Kelvin probe force microscopy showed that the MoL was also playing with the surface charge (due to surface states) on GaN, leading to increased Schottky barrier height in dark conditions. Resultant to both these phenomena, the reverse bias dark current was reduced for metal/MoL/GaN/MoL/metal PD structures. Further, the unusual photoconductive gain in the molecularly modified devices has been attributed to Schottky barrier lowering for UV illuminated conditions, leading to enhanced photocurrent.", "author_names": [ "Manjari Garg", "Bhera Ram Tak", "V Ramgopal Rao", "Rajendra Singh" ], "corpus_id": 73506152, "doc_id": "73506152", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Giant UV Photoresponse of GaN Based Photodetectors by Surface Modification Using Phenol Functionalized Porphyrin Organic Molecules.", "venue": "ACS applied materials interfaces", "year": 2019 }, { "abstract": "We report the fabrication of a GaN/sapphire ultraviolet (UV) photodetector (PD) with asymmetric (Pt Ag) and symmetric (Pt Pt) metal semiconductor metal (MSM) structure. The fabricated devices display Schottky behavior. Time dependent photoresponse analysis reveals a significant enhancement in photocurrent leading to a photoresponsivity of 37 mA/W and 267 mA/W under 13 mW optical power at 5 V bias for Pt Pt and Pt Ag devices, respectively. Further, power dependent measurements reveal a peak responsivity of 633 mA/W at 4mW optical power and 5 V bias for the Pt Ag asymmetric MSM photodetector. The significant enhancement in responsivity for asymmetric MSM UV PD is ascribed to the built in potential gradient in the GaN semiconductor, which drives a large number of charge carriers for enhanced charge collection. Further, the noise equivalent power was lowest for the Pt Ag MSM structure, which was calculated to be 4.6 x 10 14 WHz 1/2. This high performance asymmetric MSM GaN UV PD can be integrated into efficient UV PD based applications.", "author_names": [ "Shubhendra Kumar Jain", "Shibin Krishna", "Neha Aggarwal", "Rahul Kumar", "A Gundimeda", "Sudhir Husale", "Vinay Gupta", "Govind Gupta" ], "corpus_id": 104556594, "doc_id": "104556594", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Effect of Metal Contacts on a GaN/Sapphire Based MSM Ultraviolet Photodetector", "venue": "Journal of Electronic Materials", "year": 2018 }, { "abstract": "Abstract Undoped Zinc oxide (ZnO) and Antimony doped Zinc Oxide (Sb: ZnO) nanostructures (nanocones and nanoflakes) with different doping concentrations of Sb (3 at% 6 at% and 9 at% were grown on flexible (ITO/PET) substrate using a simple hydrothermal method. The seed layer of ZnO was prepared using sol gel method, which was then used as the base to grow Sb: ZnO nanostructures by hydrothermal method. Structural, optical and electrical characteristics of undoped and Sb: ZnO nanostructures were studied for three different doping concentrations of Sb. The structural and morphological studies of the prepared samples were carried out using XRD and FESEM. EDAX was used for elemental analysis. The XRD spectrum reveals ZnO wurtzite structures. The FESEM results clearly indicate that there was no change in morphology of ZnO nanostructures with the substitution of Sb in ZnO lattices. The optical studies were performed on all samples using UV Vis spectroscopy. It was observed that the transmission and the bandgap energy reduced with an increase in doping concentration. IV curves were plotted using an impedance analyzer. The samples were studied under dark conditions and under UV light of 365 nm. A monotonic increase in electrical conductivity was observed with increase in doping concentration, asserting the fact that addition of Sb to ZnO increases the conductivity of the samples, making Sb: ZnO a good candidate for photodetection. The responsivity and efficiency of the device under UV illumination of 365 nm were found to be 2.62 A/W and 893.35% respectively, with the highest values being observed for 9 at% of Sb doping.", "author_names": [ "Nazia Fathima", "Natarajan Pradeep", "Jyothi Balakrishnan" ], "corpus_id": 104754923, "doc_id": "104754923", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Enhanced optical and electrical properties of antimony doped ZnO nanostructures based MSM UV photodetector fabricated on a flexible substrate", "venue": "Materials Science in Semiconductor Processing", "year": 2019 }, { "abstract": "Abstract In this study, the fabrication and structural characterization of Antimony (Sb) doped Zinc Oxide (ZnO) based interdigitated Metal Semiconductor Metal (MSM) Ultraviolet (UV) photodetectors are reported. Sb doped p ZnO nanostructures were grown using the sol gel and hydrothermal methods on flexible ITO/PET substrates. Aluminium (Al) interdigitated contacts of thickness 20 nm, were deposited using the thermal evaporation technique to realise planar MSM structures. The structural morphology and element analysis of the as prepared samples were studied using XRD, FESEM and EDS methods. At an applied magnetic field of 1 T, the Hall measurements revealed that the device had a resistivity of 2.0697 x 10 3 O*cm, a hole mobility of 1922 m2/(V*s) and hole concentration of 0.1571 x 1019 cm 3. The optoelectrical characterization (without and with 365 nm of UV light) was performed on the MSM photodetectors with different finger electrode spacing i.e. gap sizes (0.1 cm, 0.2 cm and 0.3 cm) The results show that the device with finger spacing of 0.1 cm exhibited the maximum photocurrent. The responsivity and external quantum efficiency were calculated as 3.797 A/W and 1292% respectively. The flexible device was subjected to mechanical stress, and the dark current and photocurrent were measured for various bending/ convex arc angles (29.980, 48.720, 64.960 and 97.450) It was observed that the dark current and photocurrent reduce with the increase in bending angles. The current values were reproducible even with repeated flexing and relaxing of the device. This proved that the adhesion of the active layer of Sb doped p ZnO to the ITO/PET substrate is good, which makes it a good device.", "author_names": [ "Nazia Fathima", "Natarajan Pradeep", "Jyothi Balakrishnan" ], "corpus_id": 104385258, "doc_id": "104385258", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Investigations of the effects of electrode geometry and mechanical stress on Antimony doped Zinc Oxide nanostructures based MSM UV photodetectors fabricated on flexible substrates", "venue": "Solar Energy Materials and Solar Cells", "year": 2019 }, { "abstract": "Abstract This work reports the ultraviolet (UV) detection characteristics of zinc oxide (ZnO) nanorods (NR's) based metal semiconductor metal (MSM) devices. ZnO NR's were grown on silicon (Si) substrates (p type) by low temperature hydrothermal method in two steps. In the first step, approximately 50 nm thick pure ZnO seed layer was grown on Si, then in the second step, main growth of ZnO NR's were done above seed layer. The structural morphology of ZnO NR's were investigated by atomic force microscope (AFM) and by cross sectional scanning electron microscopy (X SEM) respectively. The results showed that high density NR's were grown uniformly above the ZnO seed layer and the tip of NR's were found in the shape of a hexagonal. After the growth of ZnO NR's, interdigited palladium (Pd) electrodes were deposited by using shadow mask technique. The electrical characterization of the Pd/ZnO NR's/Pd based detectors was studied under UV light. The values of contrast ratio and responsivity were calculated from I V characteristics of MSM UV detectors. These results may be helpful for the simplistic fabrication of hydrothermally grown ZnO NR's based UV detectors.", "author_names": [ "Shaivalini Singh", "Si-Hyun Park" ], "corpus_id": 125303315, "doc_id": "125303315", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Fabrication and properties of ZnO nanorods based MSM UV detectors on silicon substrates", "venue": "", "year": 2017 }, { "abstract": "", "author_names": [ "Shuang Liang", "W Cai", "Yan Li", "Yaoxing Liu", "Yicheng Lu", "Chuong Anh Tran", "Robert Frank Karlicek", "Ian T Ferguson" ], "corpus_id": 97809568, "doc_id": "97809568", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "GaN based MSM UV photodetectors", "venue": "", "year": 1996 }, { "abstract": "Abstract We report the fabrication and UV sensing properties of tower like GaN nanostructures. Material properties of GaN have been characterized by X ray diffractometer, transmission electron microscopy, and micro Raman and photoluminescence (PL) analysis. Temperature dependent PL measurement proves the strong band edge emission and negligible yellow emission band of the tower like GaN, which signifies the high crystal quality of GaN. The optimized UV photodetector in MSM structure based on the tower like GaN shows a response current of 52 mA and a responsivity of 122.07 mA/W at 3 V bias. Furthermore, the fast UV response of the device exhibits less than 82 ms rise time and 164 ms decay time, respectively. The work indicates a promising quality of GaN nanostructure by simple and economic CVD route and its potential application in UV light sensing devices.", "author_names": [ "Ting Wang", "Fa Cao", "Xiaohong Ji", "Qinyuan Zhang" ], "corpus_id": 202155111, "doc_id": "202155111", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Study on tower like GaN nanostructure: Growth, optical and fast UV sensing properties", "venue": "Superlattices and Microstructures", "year": 2019 }, { "abstract": "A model of currents in GaN based metal semiconductor metal(MSM) UV photodetectors have been obtained in one dimensional structure using steady state continuity equations,including the effect of surface states.According to the model,the photocurrent gain is explained,and the influences of the width of depletion regions on the photocurrents as a function of the applied bias voltage are investigated.The saturation bias voltage of 6V,stable current of 6x10~ 8) A and responsivity of 0.0857A/W are experimentally obtained.These results are in good agreement with the experimental ones.", "author_names": [ "Yang Mo-hua" ], "corpus_id": 115067408, "doc_id": "115067408", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photo response in GaN based MSM UV Detectors", "venue": "", "year": 2006 } ]

[ { "abstract": "Auxetic structure and tunable phase transitions are fascinating properties for future application. Herein, we propose two three dimensional (3D) carbon honeycombs (CHC) known as Cmcm CHC and Cmmm CHC. Based on first principles calculations, these novel 3D materials exhibit auxeticity with a fascinating negative Poisson's ratio, which stems from (i) the puckered structure of Cmcm CHC along the tube axis and (ii) significant change of angle dominant deformation for Cmmm CHC in the armchair direction. In addition, the moderate strain drives semimetal to semiconductor phase transition in CHCs, which thoroughly establishes its C C bond formation. In the meantime, two new phases, namely P63/mmc CHC and P6/mmm CHC, form and exhibit semiconductor characteristics. Our results also show that Cmcm CHC and P63/mmc CHC are superhard materials. The outstanding negative Poisson's ratio and phase transition properties make CHCs highly versatile for innovative applications in microelectromechanical and nanoelectronic devices.", "author_names": [ "Yanchun Li", "Shuaiwei Wang", "Bao-cheng Yang" ], "corpus_id": 235479304, "doc_id": "235479304", "n_citations": 0, "n_key_citations": 0, "score": 2, "title": "Auxetic Carbon Honeycomb: Strain Tunable Phase Transitions and Novel Negative Poisson's Ratio", "venue": "ACS omega", "year": 2021 }, { "abstract": "Abstract Superhard titanium diboride (TiB2) coatings (Hv> 40 GPa) were deposited in Ar atmosphere from stoichiometric TiB2 target using an unbalanced direct current (d. c. magnetron. Polished Si (0 0 1) stainless steel, high speed steel (HSS) and tungsten carbide (WC) substrates were used for deposition. The influence of negative substrate bias, Us, and substrate temperature, Ts, on mechanical properties of TiB2 coatings was studied. X ray diffraction (XRD) analysis showed hexagonal TiB2 structure with (0 0 01) preferred orientation. The texture of TiB2 coatings was dependent upon the ion bombardment (Us increased from 0 to 300 V) and the substrate heating (Ts increased from room temperature (RT) to 700 degC) All TiB2 coatings were measured using microhardness tester Fischerscope H100 equipped with Vickers and Berkovich diamond indenters and exhibited high values of hardness Hv up to 34 GPa, effective Young's modulus E*=E/(1 n) ranging from 450 to 600 GPa; here E and n are the Young's modulus and Poisson's ratio, respectively, and elastic recovery We80% TiB2 coating with a maximum hardness Hv73 GPa and E*580 GPa was sputtered at Us= 200 V and Ts=RT. Macrostresses of coatings s were measured by an optical wafer curvature technique and evaluated by Stoney equation. All TiB2 coatings exhibited compressive macrostresses.", "author_names": [ "Marian Mikula", "Branislav Grancic", "Vilma Bursikova", "Adrian Csuba", "M Drzik", "Stefan Kavecky", "Andrej Plecenik", "Peter Kus" ], "corpus_id": 97666072, "doc_id": "97666072", "n_citations": 48, "n_key_citations": 2, "score": 0, "title": "Mechanical properties of superhard TiB2 coatings prepared by DC magnetron sputtering", "venue": "", "year": 2007 }, { "abstract": "The article reports on structure and mechanical properties of Ti B alloy films sputter deposited from a sintered TiB 2 target using an unbalanced dc magnetron. We present results of a systematic investigation of the effect of negative substrate bias, U s substrate ion current density i s and substrate temperature, T s on properties of Ti B films. The X ray diffraction (XRD) analysis shows that the Ti B films consist of the hexagonal TiB 2 phase with the typical (0001) texture only. The TiB x films are over stoichiometric with the ratio x=B/Ti=2.4. All Ti B films sputter ion plated in argon magnetron discharge are superhard films with hardness H>40 GPa and exhibit high values of (i) effective Young's modulus E*=E/(1 v 2 up to approximately 600 GPa and (ii) elastic recovery, W e up to approximately 82% here E and v are the Young's modulus and the Poisson's ratio, respectively. Besides, it was found that the value of the Bragg's angle 20 of the (0001) reflection line can be easily controlled by the energy delivered to the film during its growth by (I) the substrate heating T s and (2) ion bombardment (U s i s The angle 20 of the (0001) reflection increases with increasing T s from 300 to 550 degC and decreasing U s from 150 to 50 V. In this range of process parameters, the energy E p delivered to the growing film per condensing atom by ion bombardment can be adjusted to a value, at which the (0001) reflection from sputtered films is close to that of the TiB 2 (0001) powder standard. These films exhibit a low macrostress, which approaches to zero. It enables to sputter thick (up to 8 mm) superhard (H>40 GPa) Ti B films. The optimum value of E p is achieved when the Ti B film is sputtered at U s 50 V, i s 1 mA/cm 2 T s =550 degC with a deposition rate a D =52 nm/min. The Ti B film prepared under these conditions exhibits a maximum hardness of H77 GPa, measured using a computer controlled microhardness tester Fischerscope H100 at the Vickers diamond indenter load L=50 mN.", "author_names": [ "Filip Kunc", "Jindrich Musil", "Paul H Mayrhofer", "Christian Mitterer" ], "corpus_id": 135576931, "doc_id": "135576931", "n_citations": 87, "n_key_citations": 1, "score": 0, "title": "Low stress superhard Ti B films prepared by magnetron sputtering", "venue": "", "year": 2003 }, { "abstract": "Abstract This paper presents an investigation on the nonlinear flexural vibrations of carbon nanotube reinforced composite (CNTRC) laminated cylindrical shells with negative Poisson's ratios in thermal environments. The material properties of the CNTRCs are temperature dependent and the functionally graded (FG) in a piece wise pattern in the thickness direction of the shell. An extended Voigt (rule of mixture) model is employed to estimate the CNTRC material properties. The motion equations for the nonlinear flexural vibration of FG CNTRC laminated cylindrical shells are based on the Reddy's third order shear deformation theory and the von Karman type kinematic nonlinearity, and the effects of thermal environmental conditions are included. The nonlinear vibration solutions for the FG CNTRC laminated cylindrical shells can be obtained by applying a singular perturbation technique along with a two step perturbation approach. The effects of material property gradient, the temperature variation, shell geometric parameter, stacking sequence as well as the end conditions on the vibration characteristics of CNTRC laminated cylindrical shells are discussed in detail through a parametric study. The results show that negative Poisson's ratio has a significant effect on the linear and nonlinear vibration characteristics of CNTRC laminated cylindrical shells.", "author_names": [ "Hui-shen Shen", "Chong Li", "J N Reddy" ], "corpus_id": 212873960, "doc_id": "212873960", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Large amplitude vibration of FG CNTRC laminated cylindrical shells with negative Poisson's ratio", "venue": "", "year": 2020 }, { "abstract": "Abstract Artificial auxetic materials with negative Poisson's ratio enable distinctive elastic response in the direction orthogonal to the loaded direction, i.e. shrinking when compressed and expanding when stretched, compared to conventional materials. Such distinctive mechanical characteristic makes auxetic materials unique in practice. Current studies in this aspect focus mainly on the realization of beam dominated microstructures such as re entrant and chiral lattices and of cellular microstructures with orthogonal elliptical hole pattern. In this study, a novel two dimensional auxetic microstructure is designed by introducing peanut shaped holes in solid bulk matrix. Compared to the microstructure with elliptical hole pattern, the present design can produce slightly larger negative Poisson's ratio and achieve significantly lower stress level. The samples consisting of a number of centimeter scale unit cells with the peanut shaped holes are fabricated efficiently via additive manufacturing technique. Experiment and finite element simulation of tensile test are carried out on the specific sample to demonstrate the auxetic effect of the present design and simultaneously verify the computational model. Finally, effects of some parameters on Poisson's ratio, which may control the auxetic behavior of the present microstructure, are discussed for better understanding deformation mechanism of the proposed auxetic material.", "author_names": [ "Hui Wang", "Yuxuan Zhang", "Wanqing Lin", "Qing Hua Qin" ], "corpus_id": 202964601, "doc_id": "202964601", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "A novel two dimensional mechanical metamaterial with negative Poisson's ratio", "venue": "", "year": 2020 }, { "abstract": "Abstract This paper reports a study on the large amplitude nonlinear vibration of carbon nanotube reinforced composite (CNTRC) laminated plates with negative Poisson's ratios in thermal environments. The constituent materials of CNTRCs are temperature dependent and the plate is functionally graded (FG) in a piece wise pattern in the thickness direction of plate. An extended Voigt (rule of mixture) model is adopted to quantify the CNTRC material properties of the laminated plate. The governing motion equations for the large amplitude vibration of FG CNTRC laminated plates are based on the Reddy's third order shear deformation theory and the von Karman type kinematic nonlinearity framework, and the thermal effects and the reaction from elastic foundation are taken into account. The nonlinear solution of the motion equation can be obtained by applying a two step perturbation approach. The effects of material property gradient, the temperature variation, stacking sequence as well as the foundation stiffness on the vibration characteristics of CNTRC laminated plates are examined and discussed in depth through a parametric study. The results show that negative Poisson's ratio has a significant effect on the linear and nonlinear vibration characteristics of CNTRC laminated plates.", "author_names": [ "Jian Yang", "Xu-Hao Huang", "Hui-shen Shen" ], "corpus_id": 213483735, "doc_id": "213483735", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Nonlinear vibration of temperature dependent FG CNTRC laminated plates with negative Poisson's ratio", "venue": "", "year": 2020 }, { "abstract": "In this paper, a novel three dimensional (3D) unit cell structure with butterfly like perforations was designed, and negative Poisson's ratio and tunable stiffness were achieved in such a geometry. The Poisson's ratio and strain stress relationship of structures with different geometric parameters were determined using the finite element method (FEM) Samples with identical geometric variables to those of finite element models were fabricated via 3D printing technique, and their Poisson's ratios and stress strain relationships were experimentally determined and compared with the FEM results. Results showed that the proposed 3D cellular structures exhibit negative Poisson's ratios, and a minimal value of 0.7091 could be reached. The stress strain curve of each structure exhibited three distinct stages (elastic response, rib buckling and self contact) with different elastic moduli being observed at each stage, and demonstrated a tunable range of the compressive stiffness ratio between stages varying from 0.1866 to 1.4006(tunable stiffness) as determined by FEM analysis. Good agreement was found between the experimental results and FEM predictions. The design concept can be implemented and optimized for specific applications via geometric parameters manipulation.", "author_names": [ "Dong Sheng Li", "Ruicong Gao", "L Dong", "Wing-Kai Lam", "Fengpeng Zhang" ], "corpus_id": 214304874, "doc_id": "214304874", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "A novel 3D re entrant unit cell structure with negative Poisson's ratio and tunable stiffness", "venue": "", "year": 2020 }, { "abstract": "A novel foam structure is presented, which exhibits a negative Poisson's ratio. Such a material expands laterally when stretched, in contrast to ordinary materials.", "author_names": [ "Roderic S Lakes" ], "corpus_id": 21386778, "doc_id": "21386778", "n_citations": 2198, "n_key_citations": 81, "score": 0, "title": "Foam Structures with a Negative Poisson's Ratio", "venue": "Science", "year": 1987 }, { "abstract": "Four dimensional (4D) printing, integrates transformation information into three dimensional (3D) printed structures, which means that 3D printed structures are able to change their shapes, properties, or functionalities over time. Here, two types of shape memory personalized vascular stents with negative Poisson's ratio structure are developed via 4D printing. The genetic algorithm is used to optimize the structure. Axial compression tests, radial compression tests and three point bending tests are carried out to study the mechanical properties of the stents. In addition, fluid structure interaction and stress distribution during the shape recovery process are investigated based on finite element method. The shape memory behaviors of the stents are excellent and in vitro feasibility tests demonstrate that the stents can expand the simulated narrow blood vessel rapidly. Therefore, 4D printed shape memory stents with negative Poisson's ratio structure are highly promising for the treatment of vascular stenosis.", "author_names": [ "Cheng-Li Lin", "Lijin Zhang", "Yanju Liu", "Liwu Liu", "Jin-song Leng" ], "corpus_id": 216284327, "doc_id": "216284327", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "4D printing of personalized shape memory polymer vascular stents with negative Poisson's ratio structure: A preliminary study", "venue": "", "year": 2020 }, { "abstract": "Abstract Nanocomposite materials, such as carbon nanotube reinforced composites (CNTRCs) have emerged as a novel engineering material. They have received growing attentions in various engineering sectors. The fabrication process has also offered the possibility to design and make this type of material to have desired features, such as being functionally graded (FG) or/and having negative Poison's ratio. This paper reports an investigation on the nonlinear flexural behavior of auxetic laminated beams with each layer is made of CNTRC. Each layer may have different CNT volume fractions and the functional grading occurs in the thickness direction of the beam in the piece wise pattern. The extended rule of mixture model is used to evaluate the temperature dependent material properties of CNTRCs. The governing equations for the nonlinear bending of FG CNTRC laminated beams are derived based on the high order shear deformation beam theory. These equations include the geometrical nonlinearity in the von Karman sense and take into account the thermal effect and the beam foundation interaction. The nonlinear bending solutions can be obtained by employing a two step perturbation approach. The nonlinear flexural responses of FG CNTRC laminated beams under a uniform pressure in thermal environments are revealed and examined in details through a parametric study. Results showed that the negative Poisson's ratio has a significant impact on the nonlinear flexural behavior of CNTRC laminated beams.", "author_names": [ "Jian Yang", "Xu-Hao Huang", "Hui-shen Shen" ], "corpus_id": 213590864, "doc_id": "213590864", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Nonlinear flexural behavior of temperature dependent FG CNTRC laminated beams with negative Poisson's ratio resting on the Pasternak foundation", "venue": "", "year": 2020 } ]

[ { "abstract": "In this paper, we discuss a scheduling problem for jobs on identical parallel machines. Ready times of the jobs, precedence constraints, and sequence dependent setup times are considered. We are interested in minimizing the performance measure total weighted tardiness that is important for achieving good on time delivery performance. Scheduling problems of this type appear as subproblems in decomposition approaches for large scale job shops with automated transport of the jobs as, for example, in semiconductor manufacturing. We suggest several variants of variable neighborhood search (VNS) schemes for this scheduling problem and compare their performance with the performance of a list based scheduling approach based on the Apparent Tardiness Cost with Setups and Ready Times (ATCSR) dispatching rule. Based on extensive computational experiments with randomly generated test instances we are able to show that the VNS approach clearly outperforms heuristics based on the ATCSR dispatching rule in many situations with respect to solution quality. When using the schedule obtained by ATCSR as an initial solution for VNS, then the entire scheme is also fast and can be used as a subproblem solution procedure for complex job shop decomposition approaches.", "author_names": [ "Rene Driessel", "Lars Monch" ], "corpus_id": 10674343, "doc_id": "10674343", "n_citations": 76, "n_key_citations": 4, "score": 1, "title": "Variable neighborhood search approaches for scheduling jobs on parallel machines with sequence dependent setup times, precedence constraints, and ready times", "venue": "Comput. Ind. Eng.", "year": 2011 }, { "abstract": "In this paper, we discuss a scheduling problem for jobs on identical parallel machines. Ready times of the jobs, precedence constraints, and sequence dependent setup times are considered. We are interested in minimizing the performance measure total weighted tardiness. Scheduling problems of this type are quite important in semiconductor manufacturing. We suggest a variable neighborhood search (VNS) scheme for this problem. Based on computational experiments with stochastically generated test instances we are able to show that the VNS approach clearly outperforms heuristics based on the Apparent Tardiness Cost with Setups and Ready Times (ATCSR) dispatching rule in many situations.", "author_names": [ "Rene Driessel", "Lars Moench" ], "corpus_id": 42943945, "doc_id": "42943945", "n_citations": 21, "n_key_citations": 5, "score": 0, "title": "Scheduling jobs on parallel machines with sequence dependent setup times, precedence constraints, and ready times using variable neighborhood search", "venue": "2009 International Conference on Computers Industrial Engineering", "year": 2009 }, { "abstract": "The study considers the scheduling problem of identical parallel machines subject to minimization of the maximum completion time and the maximum tardiness expressed in a linear convex objective function. The maximum completion time or makespan is the date when the last job to be completed leaves the system. The maximum tardiness is indicated by the job that is completed with the longest delay relative its due date. Minimizing both criteria can help assuring a high utilization of the production system as well as a high level of service towards the client. Due to the complexity of the problem, a Simulated Annealing (SA) heuristic has been implemented to be able to obtain an efficient solution in a reasonable running time. A set of n jobs is assigned, to one of the m identical parallel machines. Each job is processed in only one operation before its completion after which it leaves the system. Constraints, such as due dates for each job and setup times for the machines, are considered. The resolution procedure consists of two phases and begins with an initial solution generator. Then a SA heuristic is applied for further improvement of the solution. 4 generators are used to create an initial solution and 3 to generate neighbour solutions. To test and verify the performance of the proposed resolution procedure, a computational experimentation has been realized on a set of test problems generated ad hoc.", "author_names": [ "Rasmus Persson" ], "corpus_id": 59817603, "doc_id": "59817603", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Bicriteria Simulated Annealing Algorithm for Scheduling Jobs on Parallel Machines with Sequence Dependent Setup Times", "venue": "", "year": 2008 }, { "abstract": "Abstract This paper examines scheduling in flexible flow lines with sequence dependent setup times to minimize makespan. This type of manufacturing environment is found in industries such as printed circuit board and automobile manufacture. An integer program that incorporates these aspects of the problem is formulated and discussed. Because of the difficulty in solving the IP directly, several heuristics are developed, based on greedy methods, flow line methods, the Insertion Heuristic for the Traveling Salesman Problem and the Random Keys Genetic Algorithm. Problem data is generated in order to evaluate the heuristics. The characteristics are chosen to reflect those used by previous researchers. A lower bound has been created in order to evaluate the heuristics, and is itself evaluated. An application of the Random Keys Genetic Algorithm is found to be very effective for the problems examined. Conclusions are then drawn and areas for future research are identified.", "author_names": [ "Mary E Kurz", "Ronald G Askin" ], "corpus_id": 206075066, "doc_id": "206075066", "n_citations": 249, "n_key_citations": 36, "score": 0, "title": "Scheduling flexible flow lines with sequence dependent setup times", "venue": "Eur. J. Oper. Res.", "year": 2004 }, { "abstract": "This paper presents a novel, multi objective model of a parallel machines scheduling problem that minimizes the number of tardy jobs and total completion time of all jobs. In this model, machines are considered as unrelated parallel units with different speeds. In addition, there is some precedence, relating the jobs with non identical due dates and their ready times. Sequence dependent setup times embedded in the proposed model may vary in different machines based on their characteristics. This paper proposes a two level mixed integer programming for the given problem. By solving the presented model, the associated promising results show the effectiveness of this model for small and medium sized problems, respectively.", "author_names": [ "Reza Tavakkoli-Moghaddam", "Mohammad Bazzazi" ], "corpus_id": 12860241, "doc_id": "12860241", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "MULTI OBJECTIVE UNRELATED PARALLEL MACHINES SCHEDULING WITH SEQUENCE DEPENDENT SETUP TIMES AND PRECEDENCE CONSTRAINTS", "venue": "", "year": 2008 }, { "abstract": "Much of the research on operations scheduling problems has either ignored setup times or assumed that setup times on each machine are independent of the job sequence. This paper deals with the hybrid flow shop scheduling problems in which there are sequence dependent setup times, commonly known as the SDST hybrid flow shops. This type of production system is found in industries such as chemical, textile, metallurgical, printed circuit board, and automobile manufacture. With the increase in manufacturing complexity, conventional scheduling techniques for generating a reasonable manufacturing schedule have become ineffective. An immune algorithm (IA) can be used to tackle complex problems and produce a reasonable manufacturing schedule within an acceptable time. This paper describes an immune algorithm approach to the scheduling of a SDST hybrid flow shop. An overview of the hybrid flow shops and the basic notions of an IA are first presented. Subsequently, the details of an IA approach are described and implemented. The results obtained are compared with those computed by Random Key Genetic Algorithm (RKGA) presented previously. From the results, it was established that IA outperformed RKGA.", "author_names": [ "Mostafa Zandieh", "Seyed Mohammad Taghi Fatemi Ghomi", "S M Moattar Husseini" ], "corpus_id": 205398397, "doc_id": "205398397", "n_citations": 235, "n_key_citations": 22, "score": 0, "title": "An immune algorithm approach to hybrid flow shops scheduling with sequence dependent setup times", "venue": "Appl. Math. Comput.", "year": 2006 }, { "abstract": "Abstract We consider the problem of scheduling N jobs on M parallel machines that operate at different speeds (known as uniform parallel machines) to minimize the sum of earliness and tardiness costs. Jobs are assumed to arrive in a dynamic albeit deterministic manner, and have nonidentical due dates. Violations of due dates result in earliness or tardiness penalties that may be different for different jobs. Setup times are job sequence dependent and may be different on different machines based on the characteristics of the machines. For this problem, we present a mixed integer formulation that has substantially fewer zero one variables than typical formulations for scheduling problems of this type. We present our computational experience in using this model to solve small sized problems, and discuss solution approaches for solving larger problems. Scope and purpose In JIT environments, firms face the need to complete jobs as close to their due dates as possible. Failure to do so would result in earliness and/or tardiness costs and the optimum schedule would seek to minimize functions of these costs. In many real world situations, the problem is greatly complicated by the presence of disparate issues such as: (i) uniform parallel machines that are capable of processing these jobs at different speeds; (ii) sequence dependent setup times; (iii) distinct job due dates; (iv) distinct job ready dates; and (v) distinct earliness and/or tardiness costs for each job. For this complex problem, we present a compact mathematical model and describe our computational experience in using this model to solve small sized problems.", "author_names": [ "Nagraj Balakrishnan", "John J Kanet", "Sri V Sridharan" ], "corpus_id": 36371123, "doc_id": "36371123", "n_citations": 112, "n_key_citations": 10, "score": 0, "title": "Early/tardy scheduling with sequence dependent setups on uniform parallel machines", "venue": "Comput. Oper. Res.", "year": 1999 }, { "abstract": "Each of a collection of items are to be produced on two machines (or stages) Each machine can handle only one item at a time and each item must be processed through machine one and then through machine two. The setup time plus work time for each item for each machine is known. A simple decision rule is obtained in this paper for the optimal scheduling of the production so that the total elapsed time is a minimum. A three machine problem is also discussed and solved for a restricted case.", "author_names": [ "S M Johnson" ], "corpus_id": 62713652, "doc_id": "62713652", "n_citations": 3025, "n_key_citations": 261, "score": 0, "title": "Optimal two and three stage production schedules with setup times included", "venue": "", "year": 1954 }, { "abstract": "In this paper a multicriteria scheduling problem with sequence dependent setup times on a single machine is considered. The objective function of the problem is minimization of the weighted sum of total completion time, maximum tardiness and maximum earliness. An integer programming model is developed for the problem which belongs to NP hard class. Only small size problems with up to 12 jobs can be solved by the proposed integer programming model. Heuristic methods are also used to solve large size problems. These heuristics are four tabu search based heuristics and random search method. According to computational results the tabu search based methods are effective in finding problem solutions with up to 1000 jobs.", "author_names": [ "Tamer Eren" ], "corpus_id": 14088365, "doc_id": "14088365", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "A Multicriteria Scheduling with Sequence Dependent Setup Times", "venue": "", "year": 2007 }, { "abstract": "In many manufacturing environments, multiple processing stations are used in parallel to obtain adequate capacity. Likewise, in many production environments, set up activities are required for switching between items. This work addresses scheduling in parallel machines with sequence dependent set up times and possibly non zero ready times with the goal of minimizing makespan. Non zero ready times allow for application in a continuous planning environment and will also support the expansion of the current model to a multistage production environment. An integer programming formulation is presented. Several heuristics, including approaches based on MULTI FIT, genetic algorithms and the travelling salesman problem, are then developed and compared empirically. Seven factors are identified in order to generate problem data, including the number of parallel machines, the average number of jobs per machine, set up time distribution parameters and processing time distribution parameters. The set up time matrix can be either symmetric or asymmetric but must satisfy the triangle inequality. A modified insertion heuristic is found to perform best for these types of problems.", "author_names": [ "Mary E Kurz", "Ronald G Askin" ], "corpus_id": 61681363, "doc_id": "61681363", "n_citations": 86, "n_key_citations": 10, "score": 0, "title": "Heuristic scheduling of parallel machines with sequence dependent set up times", "venue": "", "year": 2001 } ]

[ { "abstract": "Ben Fa Ming Gong Kai Liao Yi Chong Ban Dao Ti Qi Jian De Jin Shu Hu Lian Ji Qi Xing Cheng Fang Fa ,Qi Zhong ,Tong Guo Dan Hua Ceng De \"Zi Zu Zhi \"Gong Neng Bi Mian Guo Shi Ke He Qian Shi Ke ,Yi Fang Zhi Tong Hu Lian Zhong De Duan Lu He Kong Xi De Fa Sheng ,Bing Huo De Heng Ding De Gou Dao Shen Du Gai Fang Fa Bao Gua Yi Xia Bu Zou :Tong Guo Chu Bu Tui Huo Zai Ban Dao Ti Chen Di Shang Xing Cheng Dan Hua Mo ,Ban Dao Ti Chen Di Ju You Di Yi IMDMo He Wu Cha Tou ;Zai Qi Shang Xing Cheng You Dan Hua Mo De Ban Dao Ti Chen Di Shang Chen Ji Di Er IMDMo ;Zai Di Er IMDMo Shang Chen Ji Guang Ke Xiao ,Bing Shi Guang Ke Xiao Xing Cheng Tu Yang ;Li Yong Xing Cheng Tu Yang De Guang Ke Xiao Shi Ke Di Er IMDMo ,Yong Yu Xing Cheng Gou Dao ;Li Yong Hua Xue Zhi Pin Qu Chu Dan Hua Mo ;Zai Cong Zhong Qu Chu Liao Dan Hua Wu Mo De Gou Dao Zhong Chen Ji Tong Zu Dang Jin Shu Mo He Tong Jing Chong Ceng ,Ran Hou Chen Ji Tong ;Jiang Qi Shang Chen Ji You Tong De Chen Di Er Ci Tui Huo ;Yi Ji Tong Guo Hua Xue Ji Jie Pao Guang Shi Yi Er Ci Tui Huo De Chen Di Ping Tan Hua", "author_names": [ "" ], "corpus_id": 116819186, "doc_id": "116819186", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Metal interconnection of semiconductor device and forming method", "venue": "", "year": 2005 }, { "abstract": "The present invention relates to a semiconductor device and a method of forming a metal interconnection in the semiconductor device. The method is formed: in the damascene process, typically only formed on the lower metal interconnect overlying the barrier metal layer to prevent metal atoms from the lower to the upper diffusion interconnect dielectric layer. The barrier metal layer covering increased effective dielectric constant between the metal surrounding the lower portion of the lower metal interconnect dielectric layer can be prevented, and to reduce the resistance of the metal interconnection, thereby improving the reliability of the semiconductor device, the speed and or other properties.", "author_names": [ "" ], "corpus_id": 141174340, "doc_id": "141174340", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for forming metal interconnection of semiconductor device and semiconductor device", "venue": "", "year": 2007 }, { "abstract": "A method of fabricating semiconductor is disclosed. The method includes a step of depositing a low k dielectric layer, a step of forming a trench in the low dielectric layer, a step of forming a barrier layer in the trench, a step of filling the barrier layer with metal, a planarization step for the metal, and a step of forming a capping layer on the planarized metal. The capping layer comprises at least two layers. It is possible to deposit a thin film with excellent hermetic features for protecting the low k dielectric layer.", "author_names": [ "" ], "corpus_id": 140269134, "doc_id": "140269134", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method of forming metal interconnection and method of fabricating semiconductor device using the same", "venue": "", "year": 2016 }, { "abstract": "PURPOSE: A method for forming a metal interconnection of a semiconductor device and a contact structure manufactured thereby are provided to selectively form a metal film for interconnection inside a groove in a uniform manner and provide a contact structure manufactured by the metal interconnection forming method. CONSTITUTION: An inter layer dielectric is formed on a semiconductor substrate. A predetermined region of the inter layer dielectric is etched to form an inter layer dielectric pattern(105) having a recessed region. A barrier metal film(109) is formed on a front surface of the resultant on which the inter layer dielectric pattern(105) is formed. A material film(111) is formed on the semiconductor substrate on which the barrier metal film is formed to expose the barrier metal film within the recessed region. An anti nucleation layer(113) is formed by performing a native oxidation to the material film in vacuum condition. A metal film is formed to fill a region surrounded by the exposed barrier metal film. Before the barrier metal film is formed, a resistant metal layer is formed on the front surface of the resultant on which the inter layer dielectric pattern is formed.", "author_names": [ "Gil Hyeon Choi", "Byeong Hui Kim", "Jong Myeong Lee", "Sang-In Lee", "Hyeon-Seok Lim" ], "corpus_id": 223142942, "doc_id": "223142942", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for forming metal interconnection of semiconductor device and contact structure manufactured thereby", "venue": "", "year": 2000 }, { "abstract": "The invention discloses a method for forming a metal structure in a semiconductor device, and a manufacturing method for an interconnection layer. The method for forming the metal structure in the semiconductor device comprises the steps: employing one time or repeated electroplating to forming the metal structure, wherein the additive of electroplate liquid used at one time is an inorganic additive. The method not only prevents organic residues from being generated in a process of forming the metal structure when the electroplate liquid taking the inorganic additive as the additive is employed, and but also can fill a hole generated in the metal structure in the electroplating process, thereby reducing the defects generated in the metal structure, and improving the stability of the semiconductor device.", "author_names": [ "" ], "corpus_id": 141200407, "doc_id": "141200407", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for forming metal structure in semiconductor device, and manufacturing method for interconnection layer", "venue": "", "year": 2014 }, { "abstract": "PURPOSE: A method for manufacturing a metal interconnection of a semiconductor device is provided to completely fill a contact hole or groove of a highly integrated semiconductor device, by selectively forming a metal deposition blocking layer exposing the inside of the contact hole or groove of the semiconductor device having a high aspect ratio. CONSTITUTION: An interlayer dielectric is formed on a semiconductor substrate. A predetermined region of the interlayer dielectric is etched to form an interlayer dielectric pattern(105) having a recess region. A barrier metal layer(109) is formed on the resultant structure having the interlayer dielectric pattern. An insulating metal deposition blocking layer(113) exposing the barrier metal layer in the recess region is selectively deposited on the barrier metal layer. A metal plug(117) filling a region surrounded by the exposed barrier metal layer in the recess region is selectively deposited. A metal layer is formed on the entire surface of the semiconductor substrate on which the metal plug is deposited.", "author_names": [ "" ], "corpus_id": 146798708, "doc_id": "146798708", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for forming metal interconnection of semiconductor device", "venue": "", "year": 1997 }, { "abstract": "The invention first annealing (anneal under as, more particularly, in the metal wiring formation method of a semiconductor device, the first IMD layer and a tungsten contact holes a nitrogen atmosphere on a semiconductor substrate provided on the method of forming a metal wiring of a semiconductor device by forming a nitride film; The step of claim 2 IMD deposition film on a substrate on which the nitride film is formed; Applying and patterning the second photoresist film 2 IMD thereon; Forming a trench by etching the first 2 IMD film with the patterned photoresist; Removing by using the nitride film Chemical; Depositing a copper barrier metal film and the copper seed layer on said nitride film is removed, the trench and the deposition of copper; The method comprising the second annealing the substrate with the copper deposition; And to a metal wiring method for forming a semiconductor device characterized by made of an step of planarizing the second annealing the substrate in a copper CMP process. Therefore, the metal wiring formation method of a semiconductor device of the present invention is self terminated etch of the nitride film (Self Stop) using Functionality over (Over) etching or under (Under) (Open) the anti etching the copper wiring and the fine space since void) it is possible to prevent the defect such as, to obtain a constant trench structure (trench Dimension) has to obtain a uniform metal wiring resistance effect. Damascene, self etching termination layer, the rapid thermal annealing, copper metal line", "author_names": [ "" ], "corpus_id": 149973900, "doc_id": "149973900", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for forming the metal interconnection of semiconductor device", "venue": "", "year": 2004 }, { "abstract": "Technologies related to forming metal lines of a semiconductor device are disclosed. A method of forming metal lines of a semiconductor device may include forming at least one interlayer insulating layer on a semiconductor substrate, forming via holes and trenches in the at least one interlayer insulating layer, forming an anti diffusion film on the via holes and the trenches, depositing a seed Cu layer on the anti diffusion film, after the seed Cu layer is deposited, depositing rhodium (Rh) and forming Cu line on the deposited Rh. The Rh improves an adhesive force between Cu layers and prevents oxide materials or a corrosion phenomenon from occurring on the seed Cu layer. Accordingly, occurrence of delamination in subsequent processes (for example, annealing and CMP) can be prevented or reduced.", "author_names": [ "" ], "corpus_id": 139973722, "doc_id": "139973722", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Semiconductor device and method of forming metal interconnection layer thereof", "venue": "", "year": 2008 }, { "abstract": "", "author_names": [ "" ], "corpus_id": 141276779, "doc_id": "141276779", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for forming metal interconnection of semiconductor device", "venue": "", "year": 1996 }, { "abstract": "PURPOSE: A method for forming a metal interconnection layer of a semiconductor device is provided to prevent formation of a metal oxide layer on a conductive layer in a process of removing a photoresist pattern, and prevent an ashing damage and profile fail of a via hole. CONSTITUTION: A stopper layer is formed on a semiconductor substrate. An insulation layer is formed on the stopper layer. A hard mask is formed on the insulation layer. A first photoresist pattern having a first aperture is formed to expose an upper partial portion of the hard mask. A partial via hole having a first width is formed by etching partially the hard mask and the insulation layer with the use of the first photoresist pattern as a mask. The first photoresist pattern is removed. An organic material layer is coated to fill the partial via hole. A second photoresist pattern having a second aperture is formed on the substrate comprised of the organic layer. The organic layer and hard mask layer are etched by using the second photoresist pattern as a mask and the second photoresist pattern and organic layer are removed. An interconnection region having the second width and a via hole having the first width are formed by etching the insulation layer with the use of the hard mask layer as an etch mask.", "author_names": [ "" ], "corpus_id": 140439767, "doc_id": "140439767", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for forming metal interconnection layer of semiconductor device", "venue": "", "year": 2002 } ]

[ { "abstract": "We develop an open queueing network model for rapid performance analysis of semiconductor manufacturing facilities. While the use of queueing models for performance evaluation of manufacturing systems is not new, our approach differs from others in the detailed ways in which we model the different tool groups found in semiconductor wafer fabrication, as well as the way in which we characterize the effect of rework and scrap on wafer lot sizes. As an application of the model, we describe a method for performing tool planning for semiconductor lines. The method is based on a marginal allocation procedure which uses performance estimates from the queueing network model to determine the number of tools needed to achieve a target cycle time, with the objective being to minimize overall equipment cost.", "author_names": [ "Daniel P Connors", "Gerald E Feigin", "David D Yao" ], "corpus_id": 110439525, "doc_id": "110439525", "n_citations": 159, "n_key_citations": 12, "score": 0, "title": "A queueing network model for semiconductor manufacturing", "venue": "", "year": 1996 }, { "abstract": "Simulating semiconductor manufacturing lines is necessary in order to understand how various factors interact to affect the performance of these complex lines. The author reports on the effects of the commonly made assumptions of no rework, representing rework by increasing process times, no operator constraints, and no machine failures. The author uses a detailed, flexible model in which the assumptions may or may not be made. The base case, validated for a real line, makes none of the simplifying assumptions listed and is compared with subsequent runs making each assumption in turn. Generally, performance is degraded. In some cases the performance measures (resources utilization, work in process, and cycle times) remain within 20% of the base case.<ETX>", "author_names": [ "Sarah J Hood" ], "corpus_id": 110412474, "doc_id": "110412474", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Detail vs. simplifying assumptions for simulating semiconductor manufacturing lines", "venue": "Ninth IEEE/CHMT International Symposium on Electronic Manufacturing Technology,Competitive Manufacturing for the Next Decade", "year": 1990 }, { "abstract": "Advancing technology nodes with smaller process margins require improved photolithography overlay control. Overlay control at develop inspection (DI) based on optical metrology targets is well established in semiconductor manufacturing. Advances in target design and metrology technology have enabled significant improvements in overlay precision and accuracy. One approach to represent in die on device as etched overlay is to measure at final inspection (FI) with a scanning electron microscope (SEM) Disadvantages to this approach include inability to rework, limited layer coverage due to lack of transparency, and higher cost of ownership (CoO) A hybrid approach is investigated in this report whereby infrequent DI/FI bias is characterized and the results are used to compensate the frequent DI overlay results. The bias characterization is done on an infrequent basis, either based on time or triggered from change points. On a per device and per layer basis, the optical target overlay at DI is compared with SEM on device overlay at FI. The bias characterization results are validated and tracked for use in compensating the DI APC controller. Results of the DI/FI bias characterization and sources of variation are presented, as well as the impact on the DI correctables feeding the APC system. Implementation details in a high volume manufacturing (HVM) wafer fab will be reviewed. Finally future directions of the investigation will be discussed.", "author_names": [ "Honggoo Lee", "Sangjun Han", "Young-Sik Kim", "Myoungsoo Kim", "Hoyoung Heo", "Sanghuck Jeon", "Dongsub Choi", "Jeremy S Nabeth", "Irina Brinster", "Bill Pierson", "John C Robinson" ], "corpus_id": 124562234, "doc_id": "124562234", "n_citations": 5, "n_key_citations": 2, "score": 1, "title": "Device overlay method for high volume manufacturing", "venue": "SPIE Advanced Lithography", "year": 2016 }, { "abstract": "The present invention provides an exposure method that do not need to perform rework in accordance with the test results, such as at the time of lithography the displacement can suppress a decrease in yield. To this end, the present invention, the step of forming a photosensitive film on a main surface of the semiconductor substrate (S101) the process (S102) for transferring the semiconductor substrate to the device, select the check mark on the mask to the light shielding film exposing the photosensitive film a step of forming a latent image (Qian Xiang of the inspection mark (S105) at least in the heating film is the photosensitivity of which the latent image of the test mark is formed in the area of the second inspection step (S106) hovering the shape of the marks emerged inspection mark step (S107) the process (S109) of changing the set value of the exposure device at the time of selecting an exposure so that the exposure conditions are designed value according to the measuring result of measuring a shape, a device pattern on the mask onto the photosensitive film on the basis of the changed set point exposure to the process (S110) for forming a latent image of the device pattern on the photosensitive film, the process (S111) for heating the photosensitive film front, for developing the photosensitive film It includes information (S112)", "author_names": [ "" ], "corpus_id": 140945615, "doc_id": "140945615", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method of manufacturing semiconductor device and manufacturing apparatus thereof", "venue": "", "year": 2003 }, { "abstract": "PURPOSE: A method for reworking a semiconductor device manufacturing wafer is to completely remove and rework a photoresist coated abnormally by using an innoxious thinner composition having the proper melting speed and the volatility. CONSTITUTION: A photoresist(23) is coated on a semiconductor substrate(21) to form a specific pattern on the semiconductor substrate. The semiconductor substrate with the photoresist formed thereon is loaded on a rotatable vacuum chuck. A thinner composition is supplied to the loaded semiconductor substrate. The thinner composition is produced by mixing 70 wt to 80 wt of ethyl 3 ethoxy propionate, 17 wt to 23 wt of ethyl lactate, and 4 wt to 7 wt of gamma butyro lactone. The photoresist is soaked in the thinner composition for a predetermined time until it melted by the thinner composition. After rotating the vacuum chuck, the photoresist is removed by using the thinner composition.", "author_names": [ "" ], "corpus_id": 141061502, "doc_id": "141061502", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method of reworking wafer for semiconductor device and of manufacturing semiconductor device", "venue": "", "year": 1998 }, { "abstract": "Semiconductor wafer fabrication is perhaps one of the most complex manufacturing processes found today. In this paper, we construct a simulation model of partial of a wafer fab using ProModel software and analyze the effect of different input variables on selected parameters, such as cycle time, WIP level and equipment utilization rates. These input variables include arrival distribution, batch size, downtime pattern and lot release control. SEMATECH DATASET which has the original actual wafer fab data is used for our analysis. INTRODUCTION Semiconductor manufacturing differs from many other manufacturing environments by the complexity and variability of its processes. A semiconductor process can be several hundred operations long, and the machines are relatively unreliable due to the leading edge technology involved. At the same time, there are situations of re entrant processes, rework, and scrap etc. in the semiconductor manufacturing process. All of these make semiconductor factories harder to control than other plants of comparable size. Moreover, today's semiconductor industry is more dynamic and competitive than ever. Product's profit cycles are shrinking quarterly. Products that used to have a life cycle of 18 months now have average profit cycle of only 6 months. Customer demand for shorter cycle times and specialized packaging/delivery requirements is an obvious major trend. The entire semiconductor industry is very sensitive to the economic and trade climates. It is typical in the semiconductor market to have large oscillations in demand. Additionally, due to the trade off of waiting time in exchange for high equipment utilization in a factory of unreliable equipment, cycle time in semiconductor manufacturing is long in general. In this paper we provide an overall analysis of the behavior of some key parameters in semiconductor manufacturing, including the cycle time, WIP and utilization rates, in response to changes in the fab environment and lot release patterns using a simulation model of partial of a wafer fabrication (fab) using ProModel software. From these results, the major influencing parameters and the most desirable lot release pattern could be identified. SEMATECH DATASET which has the original actual wafer fab data is used for our analysis. 1 School of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798. Email: pg01538903@ntu.edu.sg 2 School of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798. Email: msiva@ntu.edu.sg Journal of The Institution of Engineers, Singapore Vol. 44 Issue 4 2004 54 In Section 2 we look at the overview of semiconductor manufacturing and wafer fabrication, followed by a general description of our research approach in Section 3. The model description is in Section 4 and experimental results are discussed in Section 5. Section 6 draws the conclusion and ideas for further research. SEMICONDUCTOR MANUFACTURING Overview of Semiconductor Manufacturing Wafer Start Wafer Fabrication Wafer Probe Assembly Final Test Product Ship Wafer Die Package Circuit Tested Circuit", "author_names": [ "Qi Chao", "Appa Iyer Sivakumar" ], "corpus_id": 14841680, "doc_id": "14841680", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "SIMULATION BASED CAUSE AND EFFECT ANALYSIS IN SEMICONDUCTOR WAFER FABRICATION", "venue": "", "year": 2004 }, { "abstract": "The semiconductor manufacturing industry is one of the most important industries in Taiwan. Wafer fabrication is an essential process in semiconductor manufacturing. However, controlling the production system on the shop floor is extremely difficult owing to the complicated manufacturing process and reentrant characteristics. In this paper, the shop floor control (SFC) integration strategies (order review/release, dispatching, and rework strategies) in wafer fabrication are considered with using several performances. We reviewed the literature on SFC strategies in wafer fabrication. The proposed combination simulation and simulated annealing (SA) algorithm is presented for SFC strategies in wafer fabrication. The objective was to seek the near global optimum solution for the combination of SFC strategies for a specific performance indicator. From the results, the proposed methodology was found to perform well for combinations of SFC strategies using different performance indicators in wafer fabrication. However, no single combination of SFC strategies could satisfy all performance indicators. Hence, considering the trade off among these production control strategies, a suitable strategy should be chosen based on the system control tactics. Considerable computational time was saved in this research.", "author_names": [ "D Y Sha", "Chao-Yang Liu" ], "corpus_id": 54967756, "doc_id": "54967756", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "A simulated annealing algorithm for integration of shop floor control strategies in semiconductor wafer fabrication", "venue": "", "year": 2003 }, { "abstract": "This paper presents the processes, steps and inspections, various testing stages involved starting from procurement of wafer onwards to individual Die form. Any semiconductor die or integrated circuit must performed all the processes of inspection and testing once it receives from any manufacturer and then it has to be procured to any Manufacturing Line for further process as a part of any Manufacturing products. This paper is also an attempt to isolate the entire good and bad Semiconductor Dies received from some Semiconductor Manufacturer at one place with complete package before going to Manufacturing Unit. It not only yields the efficiency of the Product in that Manufacturing line but also it saves a lot of manpower given for Failure Analysis, rework, retesting, etc and also it increases the Product reliability Any small change in the product which may be either due to process improvement or due to application requirements or due to material changes had a direct impact on device reliability. The device reliability depends upon avoiding any small and minute changes from the original one. For example any changes in die size which occurred due to scratch, die track cut, chips out, cracks, voids, corrosion on bond pads, glassivation, metallization, passivation, leads to decrement of Product performance. For an instant, the capacitor of cracked Die (1) becomes either half for parallel circuited or get doubled for series circuited. In both the cases, the resonance for the Product affects and hence the performance degrades. If there are any voids or corrosion on bond pads, the series inductance increases which again degrades. Hence for successful Product launching; the associated items should be understood about their functionality, performance and also to be prevented to avoid any type of changes in size and shape.", "author_names": [ "Satya Sai Srikant", "Rajendra Prasad Mahapatra" ], "corpus_id": 61633869, "doc_id": "61633869", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Semiconductor Die: Processing and Packaging", "venue": "", "year": 2012 }, { "abstract": "Although the national importance of the semiconductor industry is widely acknowledged, it is only recently that the production planning and scheduling problems encountered in this environment have begun to be addressed using industrial engineering and operations research.techniques. These problems have several features that make them difficult and challenging: random yields and rework, complex product flows, and rapidly changing products and technologies. Hence their solution will contribute considerably to die theory and practice of production planning and control. In a two part project we present a review of research in this area to date, discuss the applicability of the various approaches and suggest directions for future research. In this paper, Part I, we describe the characteristics of the semiconductor manufacturing environment and review models related to performance evaluation and production planning. Part II will review research on shop floor control in this industry to date.", "author_names": [ "Reha Uzsoy", "Chung-Yee Lee", "Louis A Martin-Vega" ], "corpus_id": 108713268, "doc_id": "108713268", "n_citations": 585, "n_key_citations": 11, "score": 0, "title": "A REVIEW OF PRODUCTION PLANNING AND SCHEDULING MODELS IN THE SEMICONDUCTOR INDUSTRY PART I: SYSTEM CHARACTERISTICS, PERFORMANCE EVALUATION AND PRODUCTION PLANNING", "venue": "", "year": 1992 }, { "abstract": "This paper deals with the lot sizing problem in which the key features of imperfections in a production process are explicitly modelled. These features include: process shifting to out of control states, detection of the out of control shifts, corrective actions following the detections, and the fixed setup and variable processing times of reworks. The problem is motivated by the wafer probe operation in semiconductor manufacturing. The key objective that drives the lot sizing decision is to reduce the total processing time on a critical resource. Such an objective is aimed at reducing the congestion level at this resource.", "author_names": [ "Hau L Lee" ], "corpus_id": 154589034, "doc_id": "154589034", "n_citations": 98, "n_key_citations": 9, "score": 0, "title": "Lot sizing to reduce capacity utilization in a production process with defective items, process corrections, and rework", "venue": "", "year": 1992 } ]

[ { "abstract": "An optical metamaterial is a composite in which subwavelength features, rather than the constituent materials, control the macroscopic electromagnetic properties of the material. Recently, properly designed metamaterials have garnered much interest because of their unusual interaction with electromagnetic waves. Whereas nature seems to have limits on the type of materials that exist, newly invented metamaterials are not bound by such constraints. These newly accessible electromagnetic properties make these materials an excellent platform for demonstrating unusual optical phenomena and unique applications such as subwavelength imaging and planar lens design. 'Negative index materials' as first proposed, required the permittivity, epsilon, and permeability, mu, to be simultaneously less than zero, but such materials face limitations. Here, we demonstrate a comparatively low loss, three dimensional, all semiconductor metamaterial that exhibits negative refraction for all incidence angles in the long wave infrared region and requires only an anisotropic dielectric function with a single resonance. Using reflection and transmission measurements and a comprehensive model of the material, we demonstrate that our material exhibits negative refraction. This is furthermore confirmed through a straightforward beam optics experiment. This work will influence future metamaterial designs and their incorporation into optical semiconductor devices.", "author_names": [ "Anthony J Hoffman", "Leonid V Alekseyev", "Scott S Howard", "Kale J Franz", "Daniel Wasserman", "Viktor A Podolskiy", "Evgenii Narimanov", "Deborah L Sivco", "Claire Gmachl" ], "corpus_id": 30194691, "doc_id": "30194691", "n_citations": 649, "n_key_citations": 14, "score": 1, "title": "Negative refraction in semiconductor metamaterials.", "venue": "Nature materials", "year": 2007 }, { "abstract": "We have considered the realization of metamaterials based on semiconductor quantum nanostructures, in particular, with the structural arrangement as in quantum cascade laser (QCL) designed to achieve optical gain in the mid infrared and terahertz part of the spectrum. The entire structure is placed in a strong external magnetic field, which facilitates the attainment of sufficient population inversion, necessary to manipulate the permittivity, and enable a left handed regime.", "author_names": [ "J Radovanovic", "S Ramovic", "Aleksandar Danicic", "V Milanovic" ], "corpus_id": 97649989, "doc_id": "97649989", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Negative refraction in semiconductor metamaterials based on quantum cascade laser design for the mid IR and THz spectral range", "venue": "", "year": 2012 }, { "abstract": "We theoretically and experimentally demonstrate negative refraction in a semiconductorsystem operating at mid infrared wavelengths. Such effect is generic and realized by electrons quantum confinement in quantum wells, acting as an adjustable resonance. (c) 2019 The Author(s)", "author_names": [ "M Ferraro", "Adrian Hierro", "Miguel Montes Bajo", "Julen Tamayo-Arrlola", "Nolwenn Le Biavan", "Maxime Hugues", "Jose Maria Ulloa", "M Giudici", "J M Chauveau", "Patrice Genevet" ], "corpus_id": 139729285, "doc_id": "139729285", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Intersubband plasmons induced negative refraction at mid IR frequency in heterostructured semiconductor metamaterials", "venue": "2019 Conference on Lasers and Electro Optics (CLEO)", "year": 2019 }, { "abstract": "We theoretically and experimentally demonstrate negative refraction in a semiconductorsystem operating at mid infrared wavelengths. Such effect is generic and realized by electrons quantum confinement in quantum wells, acting as an adjustable resonance. (c) 2019 The Author(s)", "author_names": [ "M Ferraro", "Adrian Hierro", "Miguel Montes Bajo", "Julen Tamayo-Arriola", "Nolwenn Le Biavan", "Maxime Hugues", "Jose Maria Ulloa", "M Giudici", "J M Chauveau", "Patrice Genevet" ], "corpus_id": 199687565, "doc_id": "199687565", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Intersubband plasmons induced negative refraction at mid IR frequency in heterostructured semiconductor metamaterials", "venue": "", "year": 2019 }, { "abstract": "We theoretically and experimentally demonstrate negative refraction in a semiconductorsystem operating at mid infrared wavelengths. Such effect is generic and realized by electrons quantum confinement in quantum wells, acting as an adjustable resonance. (c) 2019 The Author(s)", "author_names": [ "M Ferraro", "Adrian Hierro", "Miguel Montes Bajo", "Julen Tamayo-Arrlola", "Nolwenn Le Biavan", "Maxime Hugues", "J M Ulloa", "M Giudici", "J M Chauveau", "Patrice Genevet" ], "corpus_id": 203094654, "doc_id": "203094654", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Intersubband plasmons induced negative refraction at mid IR frequency in heterostructured semiconductor metamaterials", "venue": "", "year": 2019 }, { "abstract": "In order to avoid losses in metamaterial unit cells at frequencies of interest, caused by metallic inclusions, an active medium design has been proposed. As candidate structures for this active medium, we have chosen quantum cascade lasers because of their high output gain. Here we analyze and compare two quantum cascade structures that emit at 4.6 THz and 3.9 THz, respectively, placed under the influence of a strong magnetic field. We first solve the full system of rate equations for all relevant Landau levels, and obtain the necessary information about carrier distribution among the levels, after which we are able to evaluate the permittivity component along the growth direction of the structure. With these data one can determine the conditions under which negative refraction occurs, and calculate the values of the refractive index of the structure, as well as the range of frequencies at which the structure exhibits negative refraction for a predefined total electron sheet density.", "author_names": [ "Aleksandar Danicic", "J Radovanovic", "S Ramovic", "V Milanovic" ], "corpus_id": 124264188, "doc_id": "124264188", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Exploring negative refraction conditions for quantum cascade semiconductor metamaterials in the terahertz spectral range", "venue": "", "year": 2016 }, { "abstract": "One of the challenges in the design of metamaterials' unit cells is the reduction of losses caused by the metallic inclusions. In order to overcome this obstacle, it has been proposed to use the active medium as the unit cell. Quantum cascade lasers are great candidates for the active medium materials since they are able to provide high values of optical gain. In this paper we investigate and compare two quantum cascade structures optimized for emission frequencies lower than 2 THz and simulate the effect of a strong magnetic field applied perpendicularly to the layers. Comprehensive description of conduction band nonparabolicity is used to calculate the electronic structure, and subsequently evaluate the longitudinal optical phonon and interface roughness scattering rates and solve the system of rate equations which govern the distribution of carriers among the Landau levels. Once we assess the degree of population inversion, we have all the necessary information about the permittivity component along the growth direction of the structure and may determine the conditions under which the structure displays negative refraction.", "author_names": [ "Nikola N Vukovic", "Aleksandar Danicic", "J Radovanovic", "V Milanovic", "Dragan Indjin" ], "corpus_id": 73648831, "doc_id": "73648831", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Possibilities of achieving negative refraction in QCL based semiconductor metamaterials in the THz spectral range", "venue": "", "year": 2015 }, { "abstract": "Semiconductor metamaterials consisting of n+ GaInAs/i AlInAs heterostructures that support negative index modes in the mid infrared are reported. We demonstrate negative refraction in these metamaterials for wavelengths from 9?15 ?m over a wide range of incidence angles.", "author_names": [ "Anthony J Hoffman", "Leonid V Alekseyev", "Evgenii Narimanov", "Claire Gmachl", "Deborah L Sivco" ], "corpus_id": 35544240, "doc_id": "35544240", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Negative refraction in mid infrared semiconductor metamaterials", "venue": "2007 Quantum Electronics and Laser Science Conference", "year": 2007 }, { "abstract": "In this article, it has been theoretically shown that broad angle negative refraction is possible with asymmetric anisotropic metamaterials (AAMs) constructed by only dielectrics or lossless semiconductors at the telecommunication and relative wavelength range. Though natural uniaxial materials can exhibit negative refraction, the maximum angle of negative refraction and critical incident angle lie in a very narrow range. This problem can be overcome by our proposed structure. In our structures, negative refraction originates from the highly asymmetric elliptical iso frequency. This is artificially created by the rotated multilayer sub wavelength dielectric or semiconductor stack, which acts as an effective AAM. This negative refraction is achieved without using any negative permittivity materials such as metals. As we are using simple dielectrics, fabrication of such structures would be less complex than that of the metal based metamaterials. By considering the time harmonic field incidence, negative refraction has been demonstrated for two dimensional bi dielectric structures for TM polarization with realistic parameters. Our proposed ideas have been validated by the full wave simulations considering both the effective medium approach and realistic structure model. This device might find some important applications in photonics and optoelectronics.", "author_names": [ "Ayed Al Sayem", "Mahdy Rahman Chowdhury Mahdy", "Md Saifur Rahman" ], "corpus_id": 119238140, "doc_id": "119238140", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Broad angle negative refraction in lossless all dielectric or semiconductor based asymmetric anisotropic metamaterial", "venue": "", "year": 2016 }, { "abstract": "A possibility to realize thermotunable isotropic negative index metamaterials up to terahertz regime is theoretically investigated. The proposed composite metamaterials consist of dielectric spheres embedded randomly in a semiconductor host medium. As the variation in the intrinsic carrier density in InSb due to a variation in temperature thus changes the plasma frequency, we show theoretically the provided composite metamaterials whose index of refraction is thermally tunable and potentially less propagation loss. Furthermore, the effects of the radius of the dielectric sphere on the modulation frequency and bandwidth are discussed. Finally, we find that the design parameters for the composites can be scaled for application in the higher frequency regions.", "author_names": [ "Yu Chen", "Zhihao Chen", "Binyi Qin", "Xiaoyu Dai" ], "corpus_id": 126012176, "doc_id": "126012176", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Thermotunable Terahertz Negative Index Metamaterials with Dielectric Spheres Embedded in Semiconductor Host", "venue": "", "year": 2018 } ]

[ { "abstract": "Abstract Submillimeter scale domains offer wide ranging benefits for chemical and biological fields, which have motivated researchers to develop a diversity of strategies for manufacturing integrated microfluidic systems. Historically, microfluidic device construction has predominantly relied on micromachining technologies that are rooted in the semiconductor and microelectromechanical systems (MEMS) industries. These methodologies have enabled microfluidic platforms to be fabricated with fully integrated microelectronics a critical requirement for applications such as electrophoresis and dielectrophoresis (DEP) surface acoustic wave (SAW) actuation, digital microfluidics (e.g. via electrowetting on dielectric (EWOD) phenomena) and on chip electrochemical detection. Despite the distinguishing capabilities afforded by conventional microfabrication protocols, a number of inherent limitations have given rise to increasing interest in alternative approaches for microdevice construction in the form of additive manufacturing or \"three dimensional (3D) printing\" Here we review recent progress in the development of both 3D printed microfluidics and 3D printed microelectronics. We evaluate the distinctive benefits and constraints associated with emerging 3D printing technologies with respect to the fabrication of both microfluidic and microelectronic systems. Lastly, we examine the potential use of 3D printing based approaches for manufacturing microfluidic devices with integrated microelectronics.", "author_names": [ "Ryan D Sochol", "Eric Sweet", "Casey C Glick", "Sung-Yueh Wu", "Chen Yang", "Michael A Restaino", "Liwei Lin" ], "corpus_id": 139376038, "doc_id": "139376038", "n_citations": 101, "n_key_citations": 1, "score": 1, "title": "3D printed microfluidics and microelectronics", "venue": "", "year": 2018 }, { "abstract": "Microelectromechanical systems (MEMS) are of high interest for recent electronic applications. Their applications range from medicine to measurement technology, from microfluidics to the Internet of Things (IoT) In many cases, MEMS elements serve as sensors or actuators, e.g. in recent mobile phones, but also in future autonomously driving cars. Most MEMS elements are based on silicon, which is not deformed plastically under a load, as opposed to metals. While highly sophisticated solutions were already found for diverse MEMS sensors, actuators, and other elements, MEMS fabrication is less standardized than pure microelectronics, which sometimes blocks new ideas. One of the possibilities to overcome this problem may be the 3D printing approach. While most 3D printing technologies do not offer sufficient resolution for MEMS production, and many of the common 3D printing materials cannot be used for this application, there are still niches in which the 3D printing of MEMS enables producing new structures and thus creating elements for new applications, or the faster and less expensive production of common systems. Here, we give an overview of the most recent developments and applications in 3D printing of MEMS.", "author_names": [ "Tomasz Blachowicz", "Andrea Ehrmann" ], "corpus_id": 216107754, "doc_id": "216107754", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "3D Printed MEMS Technology Recent Developments and Applications", "venue": "Micromachines", "year": 2020 }, { "abstract": "Microfluidics devices have high importance in fields such as bioanalysis because these devices have the ability to manipulate small volumes of fluid, typically ranging from microliters to picoliters. Small samples of fluids can be quickly and easily tested using reactions performed with complex microfluidic devices. Many methods have been previously developed to create these devices, including traditional nanolithography techniques borrowed from the field of microelectronics. However, these traditional techniques are cost prohibitive for many small scale laboratories. This research explores a relatively low cost technique using a 3D printed master, which is used as a template for the fabrication of polydimethylsiloxane (PDMS) microfluidic devices. The masters are designed using computer aided design (CAD) software and can be printed and modified relatively quickly. We have developed a protocol for creating simple microfluidic devices using a 3D printer and PDMS adhered to glass. We have also explored methods to overcome the size limits of the 3D printed master templates by using shrinkable polymers and modified channel geometries to create a flow focusing channel. This relatively simple and lower cost technique can now be scaled to more complicated device designs and", "author_names": [ "Robyn Collette", "Eric C Novak", "Daniel Rosen", "Kathryn Shirk" ], "corpus_id": 55187322, "doc_id": "55187322", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Developing a Protocol for Creating Microfluidic Devices with a 3D Printer", "venue": "", "year": 2015 }, { "abstract": "In this research an integrated 3D printed laboratory on a chip system was developed based on integrating conventional silicon bio sensing systems with silver screen printed electronics. It was found that by integrating 220mm width micro channels, fabricated using 3D printed polymers, that this offered a means for the development of a microfluidic device with the further possibility for electrically integrating different elements through depositing screen printed silver contacts. The objective was to achieve low resistance and high reliability with low cost for manufacturing 3D printed point of care (POC) diagnostic devices.", "author_names": [ "Caitlin McCall", "Zari Tehrani" ], "corpus_id": 208054742, "doc_id": "208054742", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "3D printed lab on a chip with microelectronics and silicon integration", "venue": "", "year": 2017 }, { "abstract": "Article history: Received 15 June 2017 Received in revised form 14 December 2017 Accepted 16 December 2017 Available online 21 December 2017 Submillimeter scale domains offer wide ranging benefits for chemical and biological fields, which havemotivated researchers to develop a diversity of strategies formanufacturing integratedmicrofluidic systems. Historically, microfluidic device construction has predominantly relied onmicromachining technologies that are rooted in the semiconductor and microelectromechanical systems (MEMS) industries. These methodologies have enabled microfluidic platforms to be fabricatedwith fully integratedmicroelectronics a critical requirement for applications such as electrophoresis and dielectrophoresis (DEP) surface acoustic wave (SAW) actuation, digital microfluidics (e.g. via electrowetting on dielectric (EWOD) phenomena) and on chip electrochemical detection. Despite the distinguishing capabilities afforded by conventional microfabrication protocols, a number of inherent limitations have given rise to increasing interest in alternative approaches formicrodevice construction in the form of additive manufacturing or \"three dimensional (3D) printing\" Here we review recent progress in the development of both 3D printedmicrofluidics and 3D printedmicroelectronics. We evaluate the distinctive benefits and constraints associated with emerging 3D printing technologies with respect to the fabrication of both microfluidic and microelectronic systems. Lastly, we examine the potential use of 3D printing based approaches for manufacturing microfluidic devices with integrated microelectronics. (c) 2017 Elsevier B.V. All rights reserved.", "author_names": [ "Ryan D Sochol", "Eric Sweet", "Casey C Glick", "Sung-Yueh Wu", "Chen Yang", "Michael A Restaino", "Liwei Lin" ], "corpus_id": 165160714, "doc_id": "165160714", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "3 D printed micro fl uidics and microelectronics", "venue": "", "year": 2017 }, { "abstract": "Abstract Development of a three dimensional (3D) vascular microfluidic chip is one of the important challenges for the study vascular related diseases and new drugs. To date, however, realization of in vivo like blood vessel chips based on soft or photo lithographic fabrication methods have limitations such as complex fabrication processes, tedious manual labor, and frequent assembly failure. In this study, we describe the development of a 3D cell culture chip by utilizing a stereolithographic printer. The microfluidic chip was fabricated using a resin made of 30% (v/v in water) poly(ethylene glycol) diacrylate (MW 700) (30% PEG DA 700) a UV initiator (Irgacure 819 (IRG) and a photosensitizer (2 isopropylthioxanthone (ITX) for constructing a cytocompatible hydrogel structure. The 3D printed cell culture chip is transparent, enabling cell culture and observation of cell proliferation. Endothelial cells were cultured to mimic in vivo like blood vessel architecture within the 3D printed chip. After EAhy926 cell cultivation, cell viability was confirmed by a live/dead cell assay and cultured cells were stained with Calcein AM (Green) and Ethidium homodim 1 (Red) In addition, endothelial cells were successfully cultured in a 3D printed vascular tube like architecture in PEG DA 700. Creating a vascular microfluidic chip with 30% PEG DA 700 hydrogel using automated 3D printing processes reduces fabrication steps and time, avoids any assembly and bonding, and economizes manufacturing cost. We believe our stereolithographic 3D printing method for fabricating a 3D printed vascular chip provides a cost effective, convenient, simple, and reproducible route to vascular related disease modelling and drug screening analyses.", "author_names": [ "Yong Tae Kim", "Jong Seob Choi", "Eunjeong Choi" ], "corpus_id": 234870034, "doc_id": "234870034", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Additive manufacturing of a 3D vascular chip based on cytocompatible hydrogel", "venue": "", "year": 2021 }, { "abstract": "Abstract In this research, an integrated three dimensional (3D) printed laboratory on a chip system was developed based on integrating conventional silicon biosensing systems with silver screen printed electronics. It was discovered that by integrating 220 &mgr;m width microchannels, fabricated using 3D printed polymers, it would offer a means for the development of a microfluidic device with the further possibility for electrically integrating different elements through depositing screen printed silver contacts. The objective was to achieve low resistance and high reliability with low cost for manufacturing 3D printed point of care diagnostic devices.", "author_names": [ "Daniel John Thomas", "Caitlin McCall", "Zari Tehrani", "Tim C Claypole" ], "corpus_id": 58306257, "doc_id": "58306257", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Three Dimensional Printed Laboratory on a Chip With Microelectronics and Silicon Integration", "venue": "", "year": 1970 }, { "abstract": "Next generation small satellites, also known as nanosatellites, have masses significantly lower than traditional satellites. Including the propellant mass, the total mass of a nanosatellite is often in the range of 1 to 4 kg. These satellites are being developed for numerous applications related to research, defense, and industry. Since their popularity began in the early 2000's, limitations on the downscaling of propulsion systems has proven to be problematic. Due to this, the vast majority of nanosatellite missions have limited lifespans of 90 120 days in low Earth orbit before they reenter the Earth's atmosphere. Although satellites on this scale have little available space for instrumentation, the development in the fields of microsensors, microelectronics, micromachinery, and microfluidics has increased the capabilities of small satellites tremendously. With limited options for primary propulsion and attitude control, nanosatellites would benefit greatly from the development of an inexpensive and easily implemented propulsion system. This work focuses on the development of an additively manufactured chemical propulsion system suitable for nanosatellite primary propulsion and attitude control. The availability of such a propulsion system would allow for new nanosatellite mission concepts, such as deep space exploration, maneuvering in low gravity environments, and formation flying. Experimental methods were used to develop a dual mode microthruster design which can operate in either low impulse, pseudo monopropellant mode, or high impulse, bipropellant mode. Through the use of a homogeneous catalysis scheme for gas generation, nontoxic propellants are used to produce varying levels of thrust suitable for application in nanosatellite propulsion. The use of relatively benign propellants results in a system which is safe and inexpensive to manufacture, store, transport, and handle. In addition to these advantages, the majority of the propulsion system, including propellant storage, piping, manifolding, reaction chambers, and nozzles can be 3D printed directly into the nanosatellite chassis, further reducing the overall cost of the system. This work highlights the selection process of propellants, catalysts, and nozzle geometry for the propulsion system. Experiments were performed to determine a viable catalyst solution, validate the gas generation scheme, and validate operation of the system.", "author_names": [ "Kevin Gagne" ], "corpus_id": 111836997, "doc_id": "111836997", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Development of an Additively Manufactured Microthruster for Nanosatellite Applications", "venue": "", "year": 2016 }, { "abstract": "Computed laminography with synchrotron radiation is developed and carried out for three dimensional (3d) imaging of flat, laterally extended objects with high spatial resolution. Particular experimental conditions of a stationary synchrotron have been taken into account by a scanning geometry different from that employed with conventionally moveable laboratory x ray sources. Depending on the mechanical precision of the employed sample manipulation system, high spatial resolution down to the of scale one micrometre can be attained nondestructively also for objects of large lateral size. Furthermore, the parallel beam geometry enables easy use of monochromatic radiation for optimising contrast and reducing imaging artefacts. The feasibility of the method is demonstrated by the application to the inspection of solder joints in a flip chip bonded device which shows the potential for quality assurance in microsystem devices. Introduction: The development and production of new materials and their application in components in various branches of microelectronics and microsystem technology require information on their structural perfection. Of crucial importance are especially structural properties and their relations to technological steps involved with their production. Moreover, the investigation of structureproperty relationships for the components, starting from semiconductor substrate over layers and lateral structures up to the final component, e.g. the completed laser or integrated circuit, and beyond to the entire device, e.g. the finished PCB unit or hybrid circuit, is needed. Beside laboratory methods, a reliable availability of experimental set ups stations at synchrotron radiation sources with their unique properties (high intensity and brilliance, good coherence properties of radiation at specimen) opens up advanced possibilities for nondestructive material characterization and for nondestructive testing (NDT) of components of applied and industrial research labs. The talk gives an overview illustrating synchrotron radiation inspection and defect analysis in this context by results from microelectronics and microsystem technology, such as ultra thin silicon for smart wafers, macrodefects in GaAs, dislocation density mapping in semiconductor compound wafers, growth and quality of GaN ELO structures on sapphire and SiC, elastic strain in semiconductor nanostructures, metallization layers stress migration in copper conducting lines, lasers mechanical deformation fields in high power laser bars, flipchip technology inspection of solder bumps in sensor arrays and pixel detectors, microfluidics hydrodynamical permeability of micro filters, MOEMS (micro opto electro mechanical structures) stress in micro mirror arrays. Different synchrotron imaging techniques of absorption phaseand diffraction contrast, such as holo tomography, m diffraction, rockingcurve imaging and reciprocal space imaging are employed. In the present paper, results of computed laminography are reported, which has been developed and implemented with synchrotron radiation for the first time and can be considered as a successful extension of three dimensional (3d) synchrotron imaging to flat, laterally extended devices such as microelectronic circuit boards. Today, x ray computed tomography (CT) is one of the principal methods for volume imaging in medical diagnostics and quality assurance. CT has been developed during the 1960s/70s, for cross sectional imaging in medical applications [1,2] and became in the 1980s also widely applied to NDT of materials and devices. With the installation of x ray imaging set ups at synchrotron radiation (SR) sources, highest spatial resolutions down to the submicrometre scale could be reached [3] in radiographic images and weakly contrasted materials be distinguished [4,5,6] by phase contrast imaging. Despite of the great success of CT in general, the CT inspection of flat, laterally extended objects with a high spatial resolution in comparison to the object dimensions (for instance printed circuit boards equipped with integrated circuits) is rather problematic due to strong absorption in the directions parallel to the lateral elongation. Another approach was followed by a method nowadays called classical x ray tomography. Already before the development of CT, it had been used to image specific cross sections of objects (or patients) An acquisition scan consists of synchronous movements of the x ray source and detector with respect to the object and exposing the detector (film) during the scan. In this way the so called focal plane (defined by the geometric trajectories of x ray source, object and detector during the scan) could be investigated: object features on the focal plane are imaged sharply whereas features with growing distance from this plane are rendered increasingly blurred and contribute to a background intensity in the image. The principle was already proposed in 1932 by Ziedses des Plantes [7] for the acquisition of a few arbitrary slices by a single scan. To obtain large 3d images with a multitude of slices, however, a translational scanning of the object with respect to the focal plane has to be carried out. Nowadays, in combination with digital projection data and a computerised reconstruction step [8] the scanning can be avoided: this socalled digital tomosynthesis has analogy to CT with limited angle access. Due to the availability of fast two dimensional (2d) digital detector systems and the tremendous increase of computing power it has recently found renewed interest in medical [8,9] and technical [10,11] applications where the method is also called computed laminography (CL) In this paper the development and implementation of computed laminography with synchrotron radiation, in the following called SRCL, is reported. SRCL combines laminography principles with advantages of SR imaging, owing to the use of monochromatic radiation (due to high brightness of SR) and a high spatial resolution down to the scale of one micron provided by dedicated electronic detector systems. In the following the methodic and instrumental feasibilities are demonstrated by an application to the inspection of flip chip interconnections. The method's potential for nondestructive testing of microsystem technology and devices is outlined by the obtained results. Medical tomosynthesis and laboratory CL systems are usually designed to operate with a stationary patient object and synchronously moving x ray tube and detector units. In contrast to the mobile x ray tube the stationarity of the synchrotron source has to be accounted for by a modified scanning geometry involving now fixed source and detector and a rotation of the object. As sketched in Fig. 1, for SRCL the rotation axis is inclined by an angle of th<p/2 with respect to the monochromatic x ray beam (where the limiting case of th=p/2 would correspond to CT) Figure 1: Sketch of the preliminary experimental set up implemented at beamline ID19 of the ESRF. From a coordinate system fixed to the sample and moving in the laboratory system, this scanning corresponds to synchronous movements of the source and detector on circular trajectories where the x rays follow a conic envelope during the scan. In general for all laminography methods, sampling of the reciprocal sample space is not complete. In comparison to CT there exist unsampled regions which, quite generally, may lead to artefacts in the reconstructed images. Contrary to the laboratory (strongly divergent) cone beam cases reported in [9,12] the approximations of a parallel beam and monochromatic radiation can be very well fulfilled in the case of SR imaging set ups: in the developed implementation at ESRF beamline ID19 (cf. Fig. 1) the high source to sample distance of 145 m leads to a divergence of only approximately 0.02 mrad across the field of view of 2.8 mm of the employed CCD based detector system. For instance, within the precision of one pixel size of 1.4 mm, a maximum sample depth of approximately 7 cm in direction of the x ray beam is allowed in order to stay within parallel beam conditions of one pixel precision. Moreover, the wavelength bandwidth provided by a multilayer monochromator is l/l10 2 compared to l/l1 for the laboratory case. The 3d reconstruction method is based on filtered back projection where the back projection geometry reflects the image acquisition geometry. After determining the modulation transfer function of the projection and back projection processes, a filtering of the 2d projection data is designed to yield an approximate inversion of the back projection process [9,13] In general, due to the missing information in unsampled regions of 3d reciprocal sample space, exact inversion of the back projection process is not possible which manifests in characteristic laminographic artefacts in the reconstructed image. Besides the gain of intensity and resolution of SRCL the monochromatic radiation and parallel beam geometry reduces artefacts compared to laboratory white and cone beam laminography. Results: In order to demonstrate the potential of the method for NDT of microsystem technology we present results of a laminographic scan of a flip chip bonded device. The flip chip device was fixed by means of a cylindrical sample holder made from plexiglass on a rotation table. During the laminographic scan (using axis ph, see Fig. 1) over 360 degrees a total number of 900 projection radiographs was acquired at an x ray energy of 35 keV. An axis inclination of th=p/3 was chosen. Figure 2: Cross sectional slice through the reconstructed 3d data set of a flip chip bonded device (top) A plane parallel to the printed circuit board is shown. 900 projections were acquired with an axis inclination of th=p/3 and at an x ray energy of E= 35 keV. Voxel size is 1.4 mm, image width 1200 voxels. Figure 3: Cross sectional slices perpendicular to the printed circuit board through", "author_names": [ "Lukas Helfen", "Tilo Baumbach", "D Kiel", "Petr Mikulik", "Petra Pernot", "Jose Baruchel", "Michael Kroning" ], "corpus_id": 15918194, "doc_id": "15918194", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "IMAGING OF MICRO AND NANOSTRUCTURES WITH X RAY TECHNIQUES: APPLICATIONS IN MICROELECTRONICS AND IN MICRO SYSTEM", "venue": "", "year": 2004 }, { "abstract": "The research presented in this thesis explores work on micro and nanoscale patterning and structuring, towards 3D patterning of surfaces. The undertaking of such work is key to the advancement in areas such as microelectronics, nanotechnology and device and sensor fabrication. Chapter 1 (Nanotechnology: Introduction to Small Technology) presents an introduction to the background of the thesis research and information on the concepts and techniques used throughout the thesis. The first experimental chapter, Chapter 2 (Laying the Molecular Foundations) explores the patterning of monomolecular self assembled monolayers (instead of conventional polymeric resists) with electron beam lithography to form chemical patterns on gold surfaces. The chemical patterns on the surface then direct the self assembly of gold nanoparticles with complementary chemistry. Chapter 3 (From the Foundations Upwards) utilises the self assembling ability of the nanoparticles from the previous chapter and explores how they can be incorporated into a multilayer structure on a surface. This multilayer assembly is achieved by the layer by layer deposition methodology in conjunction with a charged polyelectrolyte. The layer by layer deposition process is followed with three different characterization techniques and the results compared. The chapter also examines other routes to directly patterning the layer by layer assembled structures such as photolithography and microfluidics. Chapter 4 (Printing and Scratching) explores the versatility of the nanoparticles and polyelectrolytes (from Chapter 3) towards alternative deposition techniques; in this case, a standard consumer grade inkjet printer is used to deposit the materials to surfaces. Futhermore, an Atomic Force Microscope is then used to define patterns and structures in the printed structures. Chapter 5 (Corrugations and Collagen) introduces the recovery and transfer of micro/nanostructured gold surfaces from gold coated CD R disks to silicon substrates as a route for producing cheap, structured gold substrates. The previous chapters examine methods to control the location of materials on surfaces, the corrugated gold substrates fabricated for this chapter are used to demonstrate that the actual orientation of materials themselves can also be controlled. In this case, the naturally occurring, fibrous and bio technologically interesting material collagen is oriented on a surface by simply rotating the surface in a suspension of collagen in a novel device fabricated for these experiments. The final experimental chapter, Chapter 6 (DNA based Foundations and Walls) uses surface chemical modification to immobilise synthetic hairpin oligonucleotides carrying a photolabile group, on a silicon surface. Once immobilised on a surface, the oligonucleotides are patterned using photolithography to leave exposed single strands, which, through the specific assembly properties of DNA, are used to direct the spatially specific assembly of complementary strands carrying molecular dye or nanoparticle labels. This hybrid system shows that self assembly processes found in nature can be combined with chemical modification of surfaces and oligonucleotide strands to also form 3D dimensional structured surfaces.", "author_names": [ "Simon J Leigh" ], "corpus_id": 133835537, "doc_id": "133835537", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The formation and characterisation of micro and nanostructured surfaces through combinations of top down and bottom up fabrication methodologies", "venue": "", "year": 2010 } ]

[ { "abstract": "As the semiconductor industry advances to ever smaller nodes with finer feature sizes and more complex mask designs, reticle quality and reticle defects continue to be a top mask yield risk. The primary reticle defect quality requirement is defined as \"no reticle defects causing 10% or larger CD error on wafer\" Beginning at around the 7 nm Logic node, EUV lithography will start pilot production in several leading fabs. EUV masks stress reticle defectivity requirements for mask shops even more than optical masks due to the larger printing impact from a similar size defect on the mask, and the greater cost and longer cycle time for EUV masks. In a mask shop, generally there are three use cases for a blank inspection system, which are used to monitor and improve mask defectivity; 1) Inspecting process monitor masks, which are used to partition the mask process and identify defect excursions, 2) inspecting 'witness' blanks, which are used to measure and control defectivity in each process tool chamber and 3) inspecting incoming mask blanks to ensure defect free starting materials for advanced optical and EUV reticles. Traditionally, mask shops have been using bright field confocal technology to perform these tasks. However, due to more stringent defect requirements and the flexibility necessary to support these varied use cases, the industry requires a new approach to drive yield improvements in mask manufacturing. In this paper, we report on the introduction of a new system that provides superior sensitivity, with very high throughput and the flexibility to adapt to many different use cases in a production environment.", "author_names": [ "Gregg Inderhees", "Bill Kalsbeck", "Alexander Tan", "Paul D H Chung", "Jiuk Hur", "Eric Kwon", "Min Choo", "Wonil Cho", "Chan-Uk Jeon", "Ilyong Jang", "In-Yong Kang", "Jeonghun Seo", "Suein Son" ], "corpus_id": 70334965, "doc_id": "70334965", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Improving mask yield by implementing an advanced mask blank inspection system", "venue": "Photomask Technology", "year": 2018 }, { "abstract": "EUV lithography has been delayed due to well known issues such as source power, debris, pellicle, etc. for high volume manufacturing. For this reason, conventional optical lithography has been developed to cover more generations with various kinds of Resolution Enhancement Techniques (RETs) and new process technology like Multiple Patterning Technology (MPT) Presently, industry lithographers have been adopting two similar techniques of the computational OPC scheme such as Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO) [1] Sub 20 nm node masks including these technologies are very difficult to fabricate due to many small features which are near the limits of mask patterning process. Therefore, these masks require the unseen level of difficulty for inspection. In other words, from the viewpoint of mask inspection, it is very challenging to maintain maximum sensitivities on main features and minimum detection rates on the Sub Resolution Assist Features (SRAFs) This paper describes the proper technique as the alternative solution to overcome these critical issues with Aerial Imaging (AI) inspection and High Resolution (HR) imaging inspection.", "author_names": [ "Sang Hoon Han", "Hong Yul Jung", "Sun Pyo Lee", "In-Yong Kang", "Gi-sung Yoon", "Dong-Hoon Chung", "Chan-Uk Jeon", "Yulia Brand", "Yair Eran", "Yoad Bar-Shean", "Alexander Chereshnya", "Chung ki Lyu" ], "corpus_id": 108992329, "doc_id": "108992329", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Study of high sensitivity DUV inspection for sub 20nm devices with complex OPCs", "venue": "Photomask Technology", "year": 2014 }, { "abstract": "The availability of defect free masks remains one of the key challenges for inserting extreme ultraviolet lithography (EUVL) into high volume manufacturing, yet little data is available for understanding native defects on real masks. In this paper, a full field EUV mask is fabricated to investigate the printability of various defects on the mask. The printability of defects and identification of their source from mask fabrication to handling were studied using wafer inspection. The printable blank defect density excluding particles and patterns is 0.63/cm2. Mask inspection is shown to have better sensitivity than wafer inspection. The sensitivity of wafer inspection must be improved using through focus analysis and a different wafer stack.", "author_names": [ "Sungmin Huh", "Liping Ren", "David Chan", "Stefan Wurm", "Kenneth A Goldberg", "Iacopo Mochi", "Toshio Nakajima", "M Kishimoto", "Byungsup Ahn", "In-Yong Kang", "Joo-on Park", "Kyoungyong Cho", "Sang-in Han", "Thomas Laursen" ], "corpus_id": 56091110, "doc_id": "56091110", "n_citations": 21, "n_key_citations": 2, "score": 1, "title": "A study of defects on EUV masks using blank inspection, patterned mask inspection, and wafer inspection", "venue": "Advanced Lithography", "year": 2010 }, { "abstract": "The ITER first wall (FW) includes beryllium armor tiles joined to a CuCrZr heat sink. The FWs are one of the critical components in an ITER machine with a surface heat flux of 4.7 MW/m2 or above. The small scale mockup shall be a part of the qualification tests and used to validate the performance of the dominant manufacturing technologies before the production of larger scale components, and this mockup shall be equipped with a hypervapotron heat sink and manufacturing processes developed for a semiprototype design. The small scale mockup includes 48 beryllium armor tiles (12 mm x 12 mm) capable of withstanding the specified heat flux values. The tile thickness shall be 6 mm to minimize the beryllium surface temperature and evaporation under high thermal loads. The detailed fabrication process of semiprototype small scale mockups was developed for a qualification test in Korea. For the CuCrZr and stainless steel, the canned materials are processed into an hot isostatic pressing (HIP) device. In the case of beryllium to CuCrZr joining, the HIP was conducted at 580degC and 100 MPa. For nondestructive tests of the fabricated semiprototypes, visual and dimension inspections were performed whenever needed during the fabrication process, and ultrasonic tests were performed using ultrasonic probes. Destructive tests for the qualification semiprototype were performed on a small scale mockup, which was fabricated together with semiprototypes. The Korea heat load test facility using an electron beam system was constructed with an electron gun (maximum electric power of 800 kW) for a high heat flux application with a 300 kW high voltage power supply and maximum accelerating voltage of 60 kV. This facility was operated to evaluate the performance test of plasma facing components. A cyclic heat flux test will be performed to evaluate the ITER qualification program.", "author_names": [ "Suk-Kwon Kim", "Hyung Gon Jin", "Kyu In Shin", "Bo Guen Choi", "Eo Hwak Lee", "Jae Sung Yoon", "Yang-Il Jung", "Dong Won Lee", "Duck-Hoi Kim" ], "corpus_id": 9051998, "doc_id": "9051998", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Manufacturing and Examination for ITER Blanket First Wall Small Scale Mockups With KoHLT EB in Korea", "venue": "IEEE Transactions on Plasma Science", "year": 2014 }, { "abstract": "ABSTRACT Perfluorinated compounds (PFCs) are used in manufacturing food contact materials, including non stick cookware coatings and oil and moisture resistant paper coatings. The chemical stability of PFCs poses an issue for human safety, as they do not degrade well naturally and hence may accumulate in the body. In terms of food safety, since dietary intake is thought to be a major source of exposure to PFCs, it is necessary to assess the migration of PFCs from food packaging articles to food under typical cooking and storage conditions. An analytical method was developed for assessing the migration of 16 PFCs from food contact materials to food simulants using liquid chromatography tandem mass spectrometry. The applicability of the method for regular inspection was assessed by monitoring 312 samples. Based on the results of the exposure assessment, all food contact materials deemed to be safe for use, which evaluated migrated concentrations and dietary food intake.", "author_names": [ "Heeju Choi", "In-Ae Bae", "Jae Chun Choi", "Se-Jong Park", "MeeKyung Kim" ], "corpus_id": 51722519, "doc_id": "51722519", "n_citations": 10, "n_key_citations": 1, "score": 0, "title": "Perfluorinated compounds in food simulants after migration from fluorocarbon resin coated frying pans, baking utensils, and non stick baking papers on the Korean market", "venue": "Food additives contaminants. Part B, Surveillance", "year": 2018 }, { "abstract": "In semiconductor manufacturing processes, monitoring the quality of wafers is one of the most important steps to quickly detect process faults and significantly reduce yield loss. Fail bit maps (FBMs) represent the failed cell count during wafer functional tests and have been popularly used as one of the diagnosis tools in semiconductor manufacturing for process monitoring, root cause analysis, and yield improvements. However, the visual inspection process is costly and time consuming. Therefore, this paper proposes an automated classification procedure for failure patterns on FBMs in dynamic random access memory (DRAM) wafers. The novel matrix factorization approach, called regularized singular value decomposition, is proposed to decompose binarized FBMs into several eigen images to extract features that can provide the characteristics of the failure patterns on FBMs. By using the extracted features, k nearest neighbor classifier is employed to classify feature patterns on FBMs into single bit failure maps and non single bit failure ones. The proposed procedure is tested on real life DRAM wafer data set provided by a semiconductor manufacturing industry, and promising results have been obtained for the automatic classification of single bit and non single bit failure maps.", "author_names": [ "Byung-Hoon Kim", "Young-Seon Jeong", "Seung Hoon Tong", "In-Kap Chang", "Myong-Kee Jeongyoung" ], "corpus_id": 38584449, "doc_id": "38584449", "n_citations": 16, "n_key_citations": 2, "score": 0, "title": "A Regularized Singular Value Decomposition Based Approach for Failure Pattern Classification on Fail Bit Map in a DRAM Wafer", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2015 }, { "abstract": "The objective of this paper is to experimentally validate the previously proposed diffuse ultrasonic technique for measuring crack depth in concrete structures. The validation ultrasonic measurements are performed on real cracks that are formed in full scale reinforced concrete beams. Three reinforced concrete beams are designed and manufactured, and then placed under four point bending to create vertical cracks on the top surface of the beams. Diffuse ultrasonic measurements are conducted on these cracks using the procedure and instrumentation developed in the previous research. The measured crack depth results are compared with the results of side surface visual inspection and direct stereo microscopy measurements on cores extracted from the cracked areas. In all cases considered, the crack depths measured by the diffuse ultrasonic method appear to deviate by about 1 cm when compared to those of the core results. The possible causes of this deviation are discussed. However, the overall results show that the diffuse ultrasonic method provides consistent and reasonably accurate crack depth measurement in concrete beams.", "author_names": [ "Chi-Won In", "Kevin Arne", "Jin-Yeon Kim", "Kimberly E Kurtis", "Laurence J Jacobs" ], "corpus_id": 136463163, "doc_id": "136463163", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Estimation of Crack Depth in Concrete Using Diffuse Ultrasound: Validation in Cracked Concrete Beams", "venue": "", "year": 2016 }, { "abstract": "The availability of defect free masks remains one of the key challenges for inserting extreme ultraviolet lithography (EUVL) into high volume manufacturing. Recently both blank suppliers achieved 1 digit number of defects at 60nm in size using their M1350s. In this paper, a full field EUV mask with Teron 61X blank inspection is fabricated to see the printability of various defects on the blank using NXE 3100. Minimum printable blank defect size is 23nm in SEVD using real blank defect. Current defect level on blank with Teron 61X Phasur has been up to 70 in 132 X 132mm2. More defect reduction as well as advanced blank inspection tools to capture all printable defects should be prepared for HVM. 3.6X reduction of blank defects per year is required to achieve the requirement of HVM in the application of memory device with EUVL. Furthermore, blank defect mitigation and compensational repair techniques during mask process needs to be developed to achieve printable defect free on the wafer.", "author_names": [ "Sungmin Huh", "In-Yong Kang", "Chang Young Jeong", "Jihoon Na", "Dong Ryul Lee", "Hwan-seok Seo", "Seong-Sue Kim", "Chan-Uk Jeon", "Jonggul Doh", "Gregg Inderhees", "Jinho Ahn" ], "corpus_id": 119621527, "doc_id": "119621527", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Printability and inspectability of defects on EUV blank for 2xnm hp HVM application", "venue": "Advanced Lithography", "year": 2012 }, { "abstract": "The availability of defect free masks remains one of the key challenges for inserting extreme ultraviolet lithography (EUVL) into high volume manufacturing, yet little data is available for understanding native defects on real masks. In this paper, a full field EUV mask is fabricated to see the printability of various defects on the mask. Programmed pit defect shows that minimum printable size of pits could be 17 nm of SEVD from the AIT. However 23.1nm in SEVD is printable from the EUV ADT. Defect printability and identification of its source along from blank fabrication to mask fabrication were studied using various inspection tools. Capture ratio of smallest printable defects was improved to 80% using optimized stack of metrical on wafer and state of art wafer inspection tool. Requirement of defect mitigation technology using fiducial mark are defined.", "author_names": [ "Sungmin Huh", "In-Yong Kang", "Sang-Hyun Kim", "Hwan-seok Seo", "Dongwan Kim", "Joo-on Park", "Seong-Sue Kim", "Han-Ku Cho", "Kenneth A Goldberg", "Iacopo Mochi", "Tsutomu Shoki", "Gregg Inderhees" ], "corpus_id": 123215961, "doc_id": "123215961", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Printability and inspectability of defects on the EUV mask for sub 32nm half pitch HVM application", "venue": "Advanced Lithography", "year": 2011 }, { "abstract": "The computational lithography such as inverse lithography technique (ILT) or source mask optimization (SMO) is considered as the necessary technique for the extremely low k1 lithography process of sub 20nm node. The ideal curvilinear mask design for computational lithography gives the impacts and requires many changes on the photomask fabrication from mask data preparation to measurement and inspection. In this paper, we present the current status and new requirements for the computational lithography mask in viewpoint of the manufacturability for mass production. The manufacturability of computational lithography mask can be realized by the predictable and manageable patterning quality. Here, we have proposed new data flow for ILT which covers what the preferred target design is for ILT, new verification method, required mask model accuracy, and resolution improvement method. Furthermore, considering acceptable writing time <24 hours) and computation limit on convolution, the current ILT technique is shown to have the limit of application area.", "author_names": [ "Jin Choi", "In-Yong Kang", "Ji Soong Park", "In-kyun Shin", "Chan-Uk Jeon" ], "corpus_id": 73720698, "doc_id": "73720698", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Manufacturability of computation lithography mask: current limit and requirements for sub 20nm node", "venue": "Advanced Lithography", "year": 2013 } ]

[ { "abstract": "Using scanning tunneling microscopy (STM) and spectroscopy (STS) at the liquid/solid interface, morphology evolution process and energetic level alignment of very thin solid films (thickness: <700 pm) of the low molecular weight molecule DRCN5T and DRCN5T:[70]PCBM blend are analyzed after applying thermal annealing at different temperatures. These films exhibit a worm like pattern without thermal annealing (amorphous shape) however, after applying thermal annealing at 120 degC, the small molecule film domains crystallize verified by X ray diffraction: structural geometry becomes a well defined organized array. By using STS, the energy band diagrams of the semiconductor bulk heterojunction (blended film) at the donor acceptor interface are determined; morphology and energy characteristics can be correlated with the organic solar cells (OSC) performance. When combining thermal treatment and solvent vapor annealing processes as described in previous literature by using other techniques, OSC devices based on DRCN5T show a very acceptable power conversion efficiency of 9.0%", "author_names": [ "Irving Caballero-Quintana", "Daniel Romero-Borja", "Jose-Luis Maldonado", "Juan Nicasio-Collazo", "Olivia Amargos-Reyes", "Antonio Jimenez-Gonzalez" ], "corpus_id": 211833025, "doc_id": "211833025", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Interfacial Energetic Level Mapping and Nano Ordering of Small Molecule/Fullerene Organic Solar Cells by Scanning Tunneling Microscopy and Spectroscopy", "venue": "Nanomaterials", "year": 2020 }, { "abstract": "The structural and electronic properties of ultrathin insulator Al2O3 films on CoAl(100) have been studied using a combination of scanning tunneling spectroscopy and microscopy. The analysis of the differential conductance yields a band gap of 2.6 2.9eV for amorphous Al2O3. In the case of a well ordered alumina film, the band gap is increased to 4.5eV. On each of the oxide phases, the barrier height is to a large extent independent of local variations such as the surface corrugations or oxide steps.", "author_names": [ "Volker Rose", "Rene Franchy" ], "corpus_id": 122637075, "doc_id": "122637075", "n_citations": 23, "n_key_citations": 0, "score": 1, "title": "The band gap of ultrathin amorphous and well ordered Al2O3 films on CoAl(100) measured by scanning tunneling spectroscopy", "venue": "", "year": 2009 }, { "abstract": "We have investigated the temporal behavior of Sb2Te3 after irradiation with picosecond (ps) pump laser pulses using scanning tunneling microscope (STM) light emission synchronized with ps probe laser pulses delayed by times t after individual pump pulses. We determined the gap energy D E at the F point in the band diagram of Sb2Te3 from the STM light emission spectra as a function of the delay time t. We found that D E increased monotonically with t from the original value of 1.62 eV for a delay time of 0 to 15.3 ps and it decreased toward that original value (1.62 eV) for t in the time span between 15.3 and 28 ps; we saw no change in D E for t 28 ps. By comparing this t dependence of D E with the dielectric functions of the crystalline and amorphous phases of Sb2Te3, we have concluded that the phase transition from the crystalline phase toward the amorphous phase is induced by the pump pulses. The phonon energy of the A2u mode is clearly seen in the STM light emission spectra when D E is 1.62 eV, but not when D E is increased above 1.62 eV by pump pulse irradiation. This feature appears to be consistent with the Raman signals, which are much stronger for the crystalline phase than for the amorphous phase.We have investigated the temporal behavior of Sb2Te3 after irradiation with picosecond (ps) pump laser pulses using scanning tunneling microscope (STM) light emission synchronized with ps probe laser pulses delayed by times t after individual pump pulses. We determined the gap energy D E at the F point in the band diagram of Sb2Te3 from the STM light emission spectra as a function of the delay time t. We found that D E increased monotonically with t from the original value of 1.62 eV for a delay time of 0 to 15.3 ps and it decreased toward that original value (1.62 eV) for t in the time span between 15.3 and 28 ps; we saw no change in D E for t 28 ps. By comparing this t dependence of D E with the dielectric functions of the crystalline and amorphous phases of Sb2Te3, we have concluded that the phase transition from the crystalline phase toward the amorphous phase is induced by the pump pulses. The phonon energy of the A2u mode is clearly seen in the STM light emission spectra when D.", "author_names": [ "Yoichi Uehara", "Masashi Kuwahara", "Satoshi Katano", "Takenori Tanno", "Joe Sakai" ], "corpus_id": 126246593, "doc_id": "126246593", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Pump probe scanning tunneling microscope light emission spectroscopy of Sb2Te3", "venue": "", "year": 2018 }, { "abstract": "Atomic scale knowledge and control of oxidation of GaSb(100) which is a potential interface for energy efficient transistors, are still incomplete, largely due to an amorphous structure of GaSb(100) oxides. We elucidate these issues with scanning tunneling microscopy and spectroscopy. The unveiled oxidation induced building blocks cause defect states above Fermi level around the conduction band edge. By interconnecting the results to previous photoemission findings, we suggest that the oxidation starts with substituting second layer Sb sites by oxygen. Adding small amount of indium on GaSb(100) resulting in a (4 x 2) In reconstruction, before oxidation produces a previously unreported, crystalline oxidized layer of (1 x 3) O free of gap states.", "author_names": [ "Jaakko Makela", "Marjukka Tuominen", "Muhammad Yasir", "Mikhail V Kuzmin", "Johnny Dahl", "Marko Patrick John Punkkinen", "Pekka Laukkanen", "Kalevi Kokko", "Robert M Wallace" ], "corpus_id": 119887227, "doc_id": "119887227", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Oxidation of GaSb(100) and its Control Studied by Scanning Tunneling Microscopy and Spectroscopy", "venue": "", "year": 2015 }, { "abstract": "We have investigated the electronic properties of ultrathin Pb films by low temperature scanning tunneling microscopy and spectroscopy. Our results show that 30 nm thick Pb(111) films grown on atomically flat highly oriented pyrolytic graphite (HOPG) and on amorphous SiO2 are both in the strong coupling limit with transition temperature and energy gap close to the bulk value. Conductance maps and spectroscopy in the vortex state reveal a bound state at the center of the vortices, which suggest that the films are in the clean limit. Measurements of 3 nm Pb films grown on HOPG show a clear crossover to the weak coupling regime and dirty limit.", "author_names": [ "S A Moore", "Jan Fedor", "Maria Iavarone" ], "corpus_id": 122957587, "doc_id": "122957587", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Low temperature scanning tunneling microscopy and spectroscopy measurements of ultrathin Pb films", "venue": "", "year": 2015 }, { "abstract": "Amorphous nitrogenated carbon films with nitrogen atomic concentration between 12% and 29% were deposited using a filtered cathodic vacuum arc and a Kaufman type ion source. The surface topography of the samples has been investigated by scanning tunneling microscopy in ultrahigh vacuum, showing that the roughness of the film surface decreases with nitrogen concentration. Scanning tunneling spectroscopy is employed to understand the role of nitrogen in the change of the surface microstructure and electronic structure near the Fermi level. The tunneling current (I) bias voltage (V) curve is flat at low bias regions indicating a finite gap for the sample with low (12% nitrogen concentration. An increase of tunneling current and its nonlinearity along with the decrease of energy gap occurs in the samples with increase of N concentration. The observed surface density of states (dI/dV)(I/V) has been fitted as a square root function of bias voltage. An improvement of the quality of these fits in the films wi.", "author_names": [ "Somnath Bhattacharyya", "Karsten Walzer", "Michael Hietschold", "Frank Richter" ], "corpus_id": 122903934, "doc_id": "122903934", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Nitrogen doping of tetrahedral amorphous carbon films: Scanning tunneling spectroscopy", "venue": "", "year": 2001 }, { "abstract": "Using a combination of in situ ultra high vacuum variable temperature scanning tunneling microscopy, ex situ Raman spectroscopy, and scanning electron microscopy, we investigated the growth of graphene using benzene on Pd(111) at temperatures up to 1100 K. Benzene adsorbs readily on Pd(111) at room temperature and forms an ordered superstructure upon annealing at 473 K. Exposure to benzene at 673 K enhances Pd step motion and yields primarily amorphous carbon upon cooling to room temperature. Monolayer graphene domains, 10 30 nm in size, appear during annealing this sample at 873 K. Dosing benzene at 1100 K results in graphene domains with varying degrees of crystallinity, while post deposition annealing at 1100 K for 1200 s yields monolayer graphene domains larger than 150 x 150 nm2. Our results, which indicate that graphene growth on Pd(111) using benzene requires deposition/annealing temperatures higher than 673 K, are in striking contrast with the reported growth of graphene using benzene at temperatures as low as 373 K on relatively inert Cu surfaces.", "author_names": [ "Pedro J Arias", "Jan Tesar", "Abby Kavner", "Tomas Sikola", "Suneel Kodambaka" ], "corpus_id": 209520195, "doc_id": "209520195", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "In Situ Variable Temperature Scanning Tunneling Microscopy Studies of Graphene Growth Using Benzene on Pd(111)", "venue": "ACS nano", "year": 2019 }, { "abstract": "The surface electronic density of states of tetrahedral amorphous carbon has been measured by scanning tunneling microscopy and calculated by density functional theory. An analysis of these results and their comparison is presented here for a series of structures with different microscopic mass densities. The experimental structures were obtained by pulsed laser deposition with varying conditions resulting in diamond like carbon thin films. The calculated carbon structures were generated by simulating a melting cooling cycle with molecular dynamics using the density functional energetics within the local density approximation. The experimental and calculated densities of states show good agreement. Graphitic like surface reconstruction is both observed at the sp3 rich tetrahedral amorphous carbon (ta C) sample and found in the calculated ta C slab structure.", "author_names": [ "K Jarmo Koivusaari", "Tapio T Rantala", "J Levoska", "Seppo Leppavuori" ], "corpus_id": 120587784, "doc_id": "120587784", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Surface electronic density of states of tetrahedral amorphous carbon investigated by scanning tunneling spectroscopy and ab initio calculations", "venue": "", "year": 2000 }, { "abstract": "Scanning Tunneling Microscopy (STM) was used to investigate the initial stages of growth of hydrogenated amorphous carbon a C:H) films. The films were deposited on highly oriented pyrolytic graphite (HOPG) and silicon substrates both on the powered (negatively self biased) and on the grounded electrodes from a methane r.f. plasma (13.56 MHz) at 68 to 70 mTorr and room temperature. On graphite substrates, films formed at the powered electrode were observed to nucleate in clusters approximately 50A in diameter. Cluster density increased with deposition time, while cluster size remained relatively constant. The atomic structure of individual clusters was amorphous. The C H bonding in these clusters was observed by high resolution electron energy loss spectroscopy. Films formed on graphite substrates placed at the grounded electrode produced very noisy images due to an unstable tunneling gap, indicative of the material's poor electrical conductivity. On silicon substrates placed at the powered electrode, film deposition was uniform and no cluster formation was observed. The films formed were measured to be flat to within 3A rms.", "author_names": [ "Mitsuo Kawasaki" ], "corpus_id": 202613200, "doc_id": "202613200", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Lawrence Berkeley National Laboratory Recent Work Title Observation of the Initial Stages of Growth of Hydrogenated Amorphous Carbon Films by Scanning Tunneling Microscopy", "venue": "", "year": 2013 }, { "abstract": "The most important methods for studying the surface of amorphous diamond like carbon are scanning tunneling microscopy and scanning tunneling spectroscopy. In this review, publications concerned with studying the topography and electronic properties of the surface of amorphous diamond like carbon films using a tunneling microscope are considered; related publications devoted to the microprobe study of field emission from amorphous carbon and to the tunneling microscopy of metal carbon nanocomposites are also reviewed.", "author_names": [ "V I Ivanov-omskii", "A B Lodygin", "Sergey Yastrebov" ], "corpus_id": 94412728, "doc_id": "94412728", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "The scanning tunneling microscopy and scanning tunneling spectroscopy of amorphous carbon", "venue": "", "year": 2000 } ]

[ { "abstract": "Many modern electronic systems including personal computers, PDAs, cell phones, network routers, smart cards, and networked sensors to name a few need to access, store, manipulate, or communicate sensitive information, making security a serious concern in their design. Embedded systems, which account for a wide range of products from the electronics, semiconductor, telecommunications, and networking industries, face some of the most demanding security concerns on the one hand, they are often highly resource constrained, while on the other hand, they frequently need to operate in physically insecure environments.Security has been the subject of intensive research in the context of general purpose computing and communications systems. However, security is often misconstrued by embedded system designers as the addition of features, such as specific cryptographic algorithms and security protocols, to the system. In reality, it is a new dimension that designers should consider throughout the design process, along with other metrics such as cost, performance, and power.The challenges unique to embedded systems require new approaches to security covering all aspects of embedded system design from architecture to implementation. Security processing, which refers to the computations that must be performed in a system for the purpose of security, can easily overwhelm the computational capabilities of processors in both low and high end embedded systems. This challenge, which we refer to as the \"security processing gap,\" is compounded by increases in the amounts of data manipulated and the data rates that need to be achieved. Equally daunting is the \"battery gap\" in battery powered embedded systems, which is caused by the disparity between rapidly increasing energy requirements for secure operation and slow improvements in battery technology. The final challenge is the \"assurance gap,\" which relates to the gap between functional security measures (e.g. security services, protocols, and their constituent cryptographic algorithms) and actual secure implementations. This paper provides an introduction to the challenges involved in secure embedded system design, discusses recent advances in addressing them, and identifies opportunities for future research.", "author_names": [ "Srivaths Ravi", "Anand Raghunathan", "Paul C Kocher", "Sunil Hattangady" ], "corpus_id": 207155302, "doc_id": "207155302", "n_citations": 485, "n_key_citations": 15, "score": 1, "title": "Security in embedded systems: Design challenges", "venue": "TECS", "year": 2004 }, { "abstract": "This paper describes the current state of the art of side channel attacks (side channel cryptanalysis) on embedded systems. Major countermeasures proposed in the literature are reviewed and the challenges faced by embedded system designers while considering the implementation of such countermeasures are highlighted. The large number of problems to be taken into account and the highly application dependent character of side channel attacks make it impossible to advise adequate countermeasure as general solutions. The designer must therefore start by defining the adversary the device must resist against and with the resources available for him choose appropriate countermeasures against this adversary. The paper gives an overview of an ongoing research work which aims at finding novel hardware based techniques to implement countermeasures for timing and power analysis attacks.", "author_names": [ "Peter D Dawoud", "D S Dawoud", "Adronis Niyonkuru" ], "corpus_id": 208012381, "doc_id": "208012381", "n_citations": 26, "n_key_citations": 2, "score": 0, "title": "Security in Embedded Systems: Design Challenges", "venue": "", "year": 2011 }, { "abstract": "The Internet of Things (IoT) is one of the fastest growing technologies in computing, revolutionizing several application domains such as wearable computing, home automation, industrial manufacturing, etc. This rapid proliferation, however, has given rise to a plethora of new security and privacy concerns. For example, IoT devices frequently access sensitive and confidential information (e.g. physiological signals) which has made them attractive targets for various security attacks. Moreover, with the hardware components in these systems sourced from manufacturers across the globe, instances of counterfeiting and piracy have increased steadily. Security mechanisms such as device authentication and key exchange are attractive options for alleviating these challenges.In this dissertation, we address the challenge of enabling low cost and low overhead device authentication and key exchange in off the shelf embedded systems. The first part of the dissertation focuses on a hardware intrinsic mechanism and proposes the design of two Physically Unclonable Functions (PUFs) which leverage the memory (DRAM, SRAM) in the system, thus, requiring minimal (or no) additional hardware for operation. Two lightweight authentication and error correction techniques, which ensure robust operation under wide environmental and temporal variations, are also presented. Experimental results obtained from prototype implementations demonstrate the effectiveness of the design. The second part of the dissertation focuses on the application of these techniques in real world systems through a new end to end authentication and key exchange protocol in the context of an Implantable Medical Device (IMD) ecosystem. Prototype implementations exhibit an energy efficient design that guards against security and privacy attacks, thereby making it suitable for resource constrained devices such as IMDs.", "author_names": [ "Soubhagya Sutar" ], "corpus_id": 225439322, "doc_id": "225439322", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Memory based Hardware intrinsic Security Mechanisms for Device Authentication in Embedded Systems", "venue": "", "year": 2020 }, { "abstract": "Memory corruption vulnerabilities have been around for decades and rank among the most prevalent vulnerabilities in embedded systems. Yet this constrained environment poses unique design and implementation challenges that significantly complicate the adoption of common hardening techniques. Combined with the irregular and involved nature of embedded patch management, this results in prolonged vulnerability exposure windows and vulnerabilities that are relatively easy to exploit. Considering the sensitive and critical nature of many embedded systems, this situation merits significant improvement. In this work, we present the first quantitative study of exploit mitigation adoption in 42 embedded operating systems, showing the embedded world to significantly lag behind the general purpose world. To improve the security of deeply embedded systems, we subsequently present uArmor, an approach to address some of the key gaps identified in our quantitative analysis. uArmor raises the bar for exploitation of embedded memory corruption vulnerabilities, while being adoptable on the short term without incurring prohibitive extra performance or storage costs.", "author_names": [ "Ali Abbasi", "Jos Wetzels", "Thorsten Holz", "Sandro Etalle" ], "corpus_id": 198993889, "doc_id": "198993889", "n_citations": 7, "n_key_citations": 2, "score": 0, "title": "Challenges in Designing Exploit Mitigations for Deeply Embedded Systems", "venue": "2019 IEEE European Symposium on Security and Privacy (EuroS&P)", "year": 2019 }, { "abstract": "Automotive systems are currently undergoing a radical shift in the way they are designed, implemented and deployed. Such changes impose an increased complexity and a high number of requirements in order to be more automated, connected, dependable and cost effective. This raises several challenges that the embedded systems community has to face, encountered at different stages of systems development from modeling and design to software/hardware deployment and validation. This paper discusses current industrial trends and open problems in the hardware and software design of automotive systems, dictating rigorous constraints in terms of safety, real time capabilities and security which have to be considered in future automotive systems design.", "author_names": [ "Selma Saidi", "Sebastian Steinhorst", "Arne Hamann", "Dirk Ziegenbein", "Marko Wolf" ], "corpus_id": 53087949, "doc_id": "53087949", "n_citations": 18, "n_key_citations": 1, "score": 0, "title": "Future automotive systems design: research challenges and opportunities: special session", "venue": "CODES+ISSS", "year": 2018 }, { "abstract": "The edge computing paradigm has emerged to handle cloud computing issues such as scalability, security and low response time among others. This new computing trend heavily relies on ubiquitous embedded systems on the edge. Performance and energy consumption are two main factors that should be considered during the design of such systems. Focusing on performance and energy consumption, this paper studies the opportunities and challenges that a heterogeneous embedded system consisting of embedded FPGAs and GPUs (as accelerators) can provide for applications. We study three design, modeling and scheduling challenges throughout the paper. We also propose three techniques to cope with these three challenges. Applying the proposed techniques to three applications including image histogram, dense matrix vector multiplication and sparse matrix vector multiplications show 1.79x and 2.29x improvements in performance and energy consumption, respectively, when both FPGA and GPU execute the corresponding application in parallel.", "author_names": [ "Mohammad Hosseinabady", "Mohd Amiruddin Bin Zainol", "Jose Luis Nunez-Yanez" ], "corpus_id": 58028968, "doc_id": "58028968", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Heterogeneous FPGA+GPU Embedded Systems: Challenges and Opportunities", "venue": "ArXiv", "year": 2019 }, { "abstract": "Automotive systems are currently undergoing a radical shift in the way they are designed, implemented and deployed. Such changes impose an increased complexity and a high number of requirements in order to be more automated, connected, dependable and cost effective. This raises several challenges that the embedded systems community has to face, encountered at different stages of systems development from modeling and design to software/hardware deployment and validation. This paper discusses current industrial trends and open problems in the hardware and software design of automotive systems, dictating rigorous constraints in terms of safety, real time capabilities and security which have to be considered in future automotive systems design.", "author_names": [ "Selma Saidi", "Sebastian Steinhorst", "Arne Hamann", "Dirk Ziegenbein", "Marko Wolf" ], "corpus_id": 53281773, "doc_id": "53281773", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Special Session: Future Automotive Systems Design: Research Challenges and Opportunities", "venue": "2018 International Conference on Hardware/Software Codesign and System Synthesis (CODES+ISSS)", "year": 2018 }, { "abstract": "Embedded Systems account for a wide range of products and are employed in various heterogeneous domains, including but not limited to: industrial systems (e.g. manufacturing plants) critical environments (e.g. military and avionics) nomadic environments (e.g. personal wearable nodes) private spaces (e.g. residences) and public infrastructures (e.g. airports) These devices often need to access, store, manipulate and/or communicate sensitive or even critical information, making the security of their resources and services an imperative concern in their design. The problem is exacerbated by their resource constraints, their diversified application settings, frequently requiring unattended operation in physically insecure environments and dynamic network formulation, in conjunction with the ever present need for smaller size and lower production costs. This paper provides an overview of the challenges in Embedded Systems security, pertaining to node hardware and software as well as relevant network protocols and cryptographic algorithms, presents recent advances in the field and identifies opportunities for future research. Keywords embedded devices; security; denial of service; lightweight cryptography; location privacy; secure routing;", "author_names": [ "Konstantinos Fysarakis", "Charalampos Manifavas" ], "corpus_id": 53005853, "doc_id": "53005853", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Embedded Systems Security Aspects of secure embedded systems design and implementation", "venue": "", "year": 2012 }, { "abstract": "The mass integration and deployment of intelligent technologies within critical commercial, industrial and public environments have a significant impact on business operations and society as a whole. Though integration of these critical intelligent technologies pose serious embedded security challenges for technology manufacturers which are required to be systematically approached, in line with international security regulations.This paper establish security foundation for such intelligent technologies by deriving embedded security requirements to realise the core security functions laid out by international security authorities, and proposing microarchitectural characteristics to establish cyber resilience in embedded systems. To bridge the research gap between embedded and operational security domains, a detailed review of existing embedded security methods, microarchitectures and design practises is presented. The existing embedded security methods have been found ad hoc, passive and strongly rely on building and maintaining trust. To the best of our knowledge to date, no existing embedded security microarchitecture or defence mechanism provides continuity of data stream or security once trust has broken. This functionality is critical for embedded technologies deployed in critical infrastructure to enhance and maintain security, and to gain evidence of the security breach to effectively evaluate, improve and deploy active response and mitigation strategies. To this end, the paper proposes three microarchitectural characteristics that shall be designed and integrated into embedded architectures to establish, maintain and improve cyber resilience in embedded systems for next generation critical infrastructure.", "author_names": [ "Fahad Manzoor Siddiqui", "Matthew Hagan", "Sakir Sezer" ], "corpus_id": 201881626, "doc_id": "201881626", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Establishing Cyber Resilience in Embedded Systems for Securing Next Generation Critical Infrastructure", "venue": "2019 32nd IEEE International System on Chip Conference (SOCC)", "year": 2019 }, { "abstract": "Abstract As a hotspot of machine learning research, deep learning is applied in many fields. Embedded systems are becoming more and more complex and networked, so the real time performance of embedded systems and the security of network embedded devices face severe challenges. Based on this, this paper studies the real time task scheduling problem for complex embedded systems and the security of embedded network devices. For real time, this paper proposes a comprehensive task scheduling algorithm. Based on the task classification in the embedded system, different scheduling methods are adopted for different tasks, and the scheduling mode is flexibly changed as the system load changes. A dynamic integrity measurement model is established based on the star trust chain structure, and the hardware implementation mechanism of constructing dynamic trust chain in embedded system is studied. The dynamic reconfigurable hardware design method based on FPGA is applied to the construction of dynamic trust chain, and a verification system is designed to verify the dynamic measurement mechanism. This can solve the security problem of deep network embedded devices to a certain extent.", "author_names": [ "Junyan Zhou" ], "corpus_id": 225003258, "doc_id": "225003258", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Real time task scheduling and network device security for complex embedded systems based on deep learning networks", "venue": "Microprocess. Microsystems", "year": 2020 } ]

[ { "abstract": "Polarization of CdTe radiation detectors in the dark was studied theoretically by taking into account a wide set of detector characteristics relevant to the polarization. Drift diffusion and Poisson's equations were solved numerically in one dimension in time resolved regime, where the characteristic time is determined by the charging of detector bulk. Shockley Read Hall model describes the trapping/detrapping of free carriers. Both diode like (In,Al)/CdTe/Pt and symmetrical (In,Al,Pt)/CdTe/(In,Al,Pt) detectors were considered. We showed how the space charge is formed in time after detector biasing and a `dead layer' appears in the detector when the accumulated charge screens the bias. Numerical results were compared with the Conventional model of charge accumulation. The influence of temperature on polarization was analyzed and the polarization is correlated with current transient. The approach can be conveniently used to find principal properties of trap levels and contacts in semiconductor radiation detectors.", "author_names": [ "Roman Grill", "Eduard Belas", "Jan Franc", "Marek Bugar", "Stepan Uxa", "Pavel Moravec", "Pavel Hoschl" ], "corpus_id": 22991714, "doc_id": "22991714", "n_citations": 32, "n_key_citations": 1, "score": 0, "title": "Polarization Study of Defect Structure of CdTe Radiation Detectors", "venue": "IEEE Transactions on Nuclear Science", "year": 2011 }, { "abstract": "Evidence concerning the defect structure of CdTe is reviewed with particular reference to the conditions producing high resistivity material.", "author_names": [ "F A Kroger" ], "corpus_id": 135640176, "doc_id": "135640176", "n_citations": 81, "n_key_citations": 2, "score": 0, "title": "The defect structure of CdTe", "venue": "", "year": 1977 }, { "abstract": "Abstract A high temperature Hall effect study as function of cadmium pressure and temperature was carried out for pure and indium doped CdTe. The results, combined with published data on the Hall effect of quenched crystals and electronic energy level positions, are interpreted on the basis of a detailed point defect model. Parameters of the equilibrium constants of various defect formation reactions are given.", "author_names": [ "S S Chern", "Honnavalli R Vydyanath", "F A Kro\"ger" ], "corpus_id": 94766017, "doc_id": "94766017", "n_citations": 105, "n_key_citations": 1, "score": 1, "title": "The defect structure of CdTe: Hall data", "venue": "", "year": 1975 }, { "abstract": "Abstract In this work we report the influence of post deposition heat treatments on the structure of the CdTe films electro deposited on stainless steel substrates. The CdTe films were annealed in air at various temperatures and time in order to investigate the influence of post deposition heat treatments on the film structure. The various structural parameters, such as grain size, lattice constant and stress, were investigated using XRD. The results showed that the stress, grain growth and the re crystallization of CdTe depends on the post deposition annealing time and temperatures. In the initial stages of annealing when the grains grow in size, the grain growth process obeys a parabolic growth law. The re crystallization process during annealing has two stages, in the beginning, the re crystallization is dominated by random orientation of the grains followed by a second process in which once again the crystallites tend to orient in a particular direction. The value of activation energy for 20% re crystallization in CdTe was estimated as 1.17+ 0.1 eV. The as deposited film is under compressive stress and with annealing the compressive stress increases. For longer annealing times the stress changes from compressive to tensile. The calculated stress is ~10 9 dyn/cm 2 Lattice parameter of the as deposited film is larger than the powder sample and upon annealing lattice value increase and reaches a maximum and on further annealing for a long time it decreases and attains a value less than that of the powder sample. The calculated value of the change in band gap due to the stress, induced during the annealing, is in the range 13 meVD E g 17 meV.", "author_names": [ "Joel Pantoja Enriquez", "Xavier Mathew" ], "corpus_id": 98238957, "doc_id": "98238957", "n_citations": 34, "n_key_citations": 0, "score": 0, "title": "The effect of annealing on the structure of CdTe films electro deposited on metallic substrates", "venue": "", "year": 2003 }, { "abstract": "Single crystal CdTe specimens were deformed in compression at 25deg, 200deg, 300deg, and 500degC to various levels of plastic strain and to failure. Deformation characteristics at each temperature are given as curves of shear stress vs shear strain and the effect of test temperature on deformation behavior is examined. The dislocation structure of the CdTe samples deformed at high temperatures is examined using transmission electron microscopy. The relation between the deformation properties and the corresponding microstructure in CdTe is explored using previously developed models to describe metallic and nonmetallic crystalline materials.", "author_names": [ "Edward L Hall", "John B Vander Sande" ], "corpus_id": 136826692, "doc_id": "136826692", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Plastic Deformation Behavior and Dislocation Structure of CdTe Single Crystals", "venue": "", "year": 1978 }, { "abstract": "Single domain CdTe(111)B has been grown on Si(001) substrates tilted 1o 2o, and 4o toward [110] All the layers started with a double domain structure, then a transition from a double to a single domain was observed by reflection high energy electron diffraction. A microscopic picture of this transition is presented. We also measured the tilt between CdTe(111)B and Si(001) The result does not follow the tilt predicted by the currently existing model. A new model of the microscopic mechanism of CdTe(111)B growth is presented. New evidence indicates that optimizing the tilt of the substrate surface is very crucial in improving the CdTe(111)B crystal quality.", "author_names": [ "Yong P Chen", "Sivalingam Sivananthan", "J -P Faurie" ], "corpus_id": 95074027, "doc_id": "95074027", "n_citations": 56, "n_key_citations": 0, "score": 0, "title": "Structure of CdTe(111)B grown by MBE on misoriented Si(001)", "venue": "", "year": 1993 }, { "abstract": "The grain structure of CSS deposited CdTe/CdS solar cells was studied as a function of annealing time in the presence of CdCl 2 The structure was studied by chemically bevelling the cell to reveal the grains at all depths of the layer. The grain boundaries were revealed using a defect sensitive etch, and photomicrographs taken at intervals down the bevel. These photomicrographs were then analysed computationally. Histograms of grain radius for each micrograph were fitted well by the Rayleigh distribution. The average grain radii were found to vary linearly throughout the CdTe layer as r (0.107 x d) 1.06, where d is the distance from the interface. This behaviour was unaffected by the CdCl 2 treatment and is discussed with reference to a kinetic model of grain growth. Finally the use of correlation plots in analysing grain centroid distribution is described and some results presented.", "author_names": [ "M A Cousins", "Ken Durose" ], "corpus_id": 95882895, "doc_id": "95882895", "n_citations": 28, "n_key_citations": 1, "score": 0, "title": "Grain structure of CdTe in CSS deposited CdTe/CdS solar cells", "venue": "", "year": 2000 }, { "abstract": "The structure of CdTe/ZnTe superlattices has been analyzed through th/2th x ray diffraction, photoluminescence, and in situ reflection high energy electron diffraction (RHEED) measurements. Samples are found to break away from Cd_(x)Zn_(1 x)Te buffer layers as a consequence of the 6% lattice mismatch in this system. However, defect densities in these superlattices are seen to drop dramatically away from the buffer layer interface, accounting for the intense photoluminescence and high average strain fields seen in each of our samples. Observed variations in residual strains suggest that growth conditions play a role in forming misfit defects. This could explain discrepancies with calculated values of critical thickness based on models which neglect growth conditions. Photoluminescence spectra reveal that layer to layer growth proceeded with single monolayer uniformity, suggesting highly reproducible growth. Our results give hope for relatively defect free Cd_(x)Zn_(1 x)Te/Cd_(y)Zn_(1 y)Te superlattices with the potential for applications to optoelectronics offered by intense visible light emitters.", "author_names": [ "Richard H Miles", "T C Mcgill", "Sivalingam Sivananthan", "Xiang-yong Chu", "J -P Faurie" ], "corpus_id": 44050430, "doc_id": "44050430", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Structure of CdTe/ZnTe superlattices", "venue": "", "year": 1987 }, { "abstract": "The effect of ion milling on the defect structure of CdTe crystals has been investigated in the scanning electron microscope by cathodoluminescence. Enhancement in the luminescence intensity is observed after ion treatment. Luminescence spectra of treated and untreated zones of the samples indicate that ion milling causes generation of tellurium vacancies and filling of cadmium vacancies in a subsurface layer. In addition, enhancement of the concentration of cadmium vacancy related defects in the region extending up to from the layer is revealed. This effect is discussed in connection with models of p to n type conversion of CdTe during ion milling.", "author_names": [ "Gennady N Panin", "Paloma Fernandez", "Javier Piqueras" ], "corpus_id": 98219536, "doc_id": "98219536", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Effect of ion beam milling on the defect structure of CdTe", "venue": "", "year": 1996 }, { "abstract": "Atomic layer epitaxy (ALE) for growing II VI compound single crystal films has been described. The growth of CdTe films on p type CdTe(110) and (111)A substrates by ALE is shown to lead to high structural perfection. Surface crystal structure of these films is studied by LEED. The nonpolar (110) surface exhibits (1x1) symmetry while the polar (111)A surface is reconstructed showing (2x2) symmetry. Electronic valence band features are studied by angle resolved photoemission and preliminary analysis of the photoemission spectra is presented. Most of the features may be accounted for in terms of the bulk electronic structure via direct transitions including primary and secondary cone emission. An intrinsic surface state (surface resonance) likely associated with a Te derived dangling bond in the (110) film is observed.", "author_names": [ "M Pessa", "O Jylha", "P A Huttunen", "Marian A Herman" ], "corpus_id": 95119866, "doc_id": "95119866", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Epitaxial growth and electronic structure of CdTe films", "venue": "", "year": 1984 } ]

[ { "abstract": "Topological photonics has recently been proved a robust framework for manipulating light. Active topological photonic systems, in particular, enable richer fundamental physics by employing nonlinear light matter interactions, thereby opening a new landscape for applications such as topological lasing. Here we report an all dielectric topological insulator laser scheme based on semiconductor cavities formed by topologically distinct Kagome photonic crystals. The proposed planar semiconductor Kagome lattice allows broadband edge states below the light line due to photonic valley hall effect in telecommunication region, which provides a new route to retrieve nontrivial photonic topology and to develop integrated topological systems for robust light generation and transport.", "author_names": [ "Yongkang Gong", "Stephan Wong", "Anthony J Bennett", "Diana L Huffaker", "Sang Soon Oh" ], "corpus_id": 210164684, "doc_id": "210164684", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Topological Insulator Laser Using Valley Hall Photonic Crystals", "venue": "", "year": 2020 }, { "abstract": "We propose a system that exploits the fundamental features of topological photonics and synthetic dimensions to force many semiconductor laser resonators to synchronize, mutually lock, and under suitable modulation emit a train of transform limited mode locked pulses. These lasers exploit the Floquet topological edge states in a 1D array of ring resonators, which corresponds to a 2D topological system with one spatial dimension and one synthetic frequency dimension. We show that the lasing state of the multielement laser system possesses the distinct characteristics of spatial topological edge states while exhibiting topologically protected transport. The topological synthetic space edge mode imposes a constant phase difference between the multifrequency modes on the edges, and together with modulation of the individual elements forces the ensemble of resonators to mode lock and emit short pulses, robust to disorder in the multiresonator system. Our results offer a proof of concept mechanism to actively mode lock a laser diode array of many lasing elements, which is otherwise extremely difficult due to the presence of many spatial modes of the array. The topological synthetic space concepts proposed here offer an avenue to overcome this major technological challenge and open new opportunities in laser physics.", "author_names": [ "Zhaoju Yang", "Eran Lustig", "Gal Harari", "Yonatan Plotnik", "Yaakov Lumer", "Miguel A Bandres", "Mordechai Segev" ], "corpus_id": 216289597, "doc_id": "216289597", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Mode Locked Topological Insulator Laser Utilizing Synthetic Dimensions", "venue": "", "year": 2020 }, { "abstract": "Topological protection for lasers Ideas based on topology, initially developed in mathematics to describe the properties of geometric space under deformations, are now finding application in materials, electronics, and optics. The main driver is topological protection, a property that provides stability to a system even in the presence of defects. Harari et al. outline a theoretical proposal that carries such ideas over to geometrically designed laser cavities. The lasing mode is confined to the topological edge state of the cavity structure. Bandres et al. implemented those ideas to fabricate a topological insulator laser with an array of ring resonators. The results demonstrate a powerful platform for developing new laser systems. Science, this issue p. eaar4003, p. eaar4005 Lasing is observed in an edge mode of a designed optical topological insulator. INTRODUCTION Physical systems that exhibit topological invariants are naturally endowed with robustness against perturbations, as was recently demonstrated in many settings in condensed matter, photonics, cold atoms, acoustics, and more. The most prominent manifestations of topological systems are topological insulators, which exhibit scatter free edge state transport, immune to perturbations and disorder. Recent years have witnessed intense efforts toward exploiting these physical phenomena in the optical domain, with new ideas ranging from topology driven unidirectional devices to topological protection of path entanglement. But perhaps more technologically relevant than all topological photonic settings studied thus far is, as proposed by the accompanying theoretical paper by Harari et al. an all dielectric magnet free topological insulator laser, with desirable properties stemming from the topological transport of light in the laser cavity. RATIONALE We demonstrate nonmagnetic topological insulator lasers. The topological properties of the laser system give rise to single mode lasing, robustness against fabrication defects, and notably higher slope efficiencies compared to those of the topologically trivial counterparts. We further exploit the properties of the active topological platform by assembling topological insulator lasers from S chiral microresonators that enforce predetermined unidirectional lasing even in the absence of magnetic fields. RESULTS Our topological insulator laser system is an aperiodic array of 10 unit cell by 10 unit cell coupled ring resonators on an InGaAsP quantum wells platform. The active lattice uses the topological architecture suggested in the accompanying theoretical paper. This two dimensional setting is composed of a square lattice of ring resonators coupled to each other by means of link rings. The intermediary links are judiciously spatially shifted to introduce a set of hopping phases, establishing a synthetic magnetic field and two topological band gaps. The gain in this laser system is provided by optical pumping. To promote lasing of the topologically protected edge modes, we pump the outer perimeter of the array while leaving the interior lossy. We find that this topological insulator laser operates in single mode even considerably above threshold, whereas the corresponding topologically trivial realizations lase in multiple modes. Moreover, the topological laser displays a slope efficiency that is considerably higher than that in the corresponding trivial realizations. We further demonstrate the topological features of this laser by observing that in the topological array, all sites emit coherently at the same wavelength, whereas in the trivial array, lasing occurs in localized regions, each at a different frequency. Also, by pumping only part of the topological array, we demonstrate that the topological edge mode always travels along the perimeter and emits light through the output coupler. By contrast, when we pump the trivial array far from the output coupler, no light is extracted from the coupler because the lasing occurs at stationary modes. We also observe that, even in the presence of defects, the topological protection always leads to more efficient lasing compared to that of the trivial counterpart. Finally, to show the potential of this active system, we assemble a topological system based on S chiral resonators, which can provide new avenues to control the topological features. CONCLUSION We have experimentally demonstrated an all dielectric topological insulator laser and found that the topological features enhance the lasing performance of a two dimensional array of microresonators, making them lase in unison in an extended topologically protected scatter free edge mode. The observed single longitudinal mode operation leads to a considerably higher slope efficiency as compared to that of a corresponding topologically trivial system. Our results pave the way toward a new class of active topological photonic devices, such as laser arrays, that can operate in a coherent fashion with high efficiencies. Topological insulator laser. (A) Top view image of the lasing pattern (topological edge mode) in a 10 unit cell by 10 unit cell array of topologically coupled resonators and the output ports. (B) Output intensity versus pump intensity for a topological insulator laser and its trivial counterpart. The enhancement of the slope efficiency is about threefold. Comparing the power emitted in the single mode of the topological array to that of the highest power mode in the trivial array, the topological outperforms the trivial by more than a factor of 10. (C) Emission spectra from a topological insulator laser and its topologically trivial counterpart. au, arbitrary units. Physical systems exhibiting topological invariants are naturally endowed with robustness against perturbations, as manifested in topological insulators materials exhibiting robust electron transport, immune from scattering by defects and disorder. Recent years have witnessed intense efforts toward exploiting these phenomena in photonics. Here we demonstrate a nonmagnetic topological insulator laser system exhibiting topologically protected transport in the cavity. Its topological properties give rise to single mode lasing, robustness against defects, and considerably higher slope efficiencies compared to the topologically trivial counterparts. We further exploit the properties of active topological platforms by assembling the system from S chiral microresonators, enforcing predetermined unidirectional lasing without magnetic fields. This work paves the way toward active topological devices with exciting properties and functionalities.", "author_names": [ "Miguel A Bandres", "Steffen Wittek", "Gal Harari", "Midya Parto", "Jinhan Ren", "Mordechai Segev", "Demetrios N Christodoulides", "Mercedeh Khajavikhan" ], "corpus_id": 4523587, "doc_id": "4523587", "n_citations": 558, "n_key_citations": 7, "score": 1, "title": "Topological insulator laser: Experiments", "venue": "Science", "year": 2018 }, { "abstract": "Topological protection for lasers Ideas based on topology, initially developed in mathematics to describe the properties of geometric space under deformations, are now finding application in materials, electronics, and optics. The main driver is topological protection, a property that provides stability to a system even in the presence of defects. Harari et al. outline a theoretical proposal that carries such ideas over to geometrically designed laser cavities. The lasing mode is confined to the topological edge state of the cavity structure. Bandres et al. implemented those ideas to fabricate a topological insulator laser with an array of ring resonators. The results demonstrate a powerful platform for developing new laser systems. Science, this issue p. eaar4003, p. eaar4005 Lasing is observed in an edge mode of a designed optical topological insulator. INTRODUCTION Topological insulators emerged in condensed matter physics and constitute a new phase of matter, with insulating bulk and robust edge conductance that is immune to imperfections and disorder. To date, topological protection is known to be a ubiquitous phenomenon, occurring in many physical settings, ranging from photonics and cold atoms to acoustic, mechanical, and elastic systems. So far, however, most of these studies were carried out in entirely passive, linear, and conservative settings. RATIONALE We propose topological insulator lasers: lasers whose lasing mode exhibits topologically protected transport without magnetic fields. Extending topological physics to lasers is far from natural. In fact, lasers are built on foundations that are seemingly inconsistent with the essence of topological insulators: They require gain (and thus are non Hermitian) they are nonlinear entities because the gain must be saturable, and they are open systems because they emit light. These properties, common to all lasers, cast major doubts on the possibility of harnessing topological features to make a topological insulator laser. Despite this common mindset, we show that the use of topological properties leads to highly efficient lasers, robust to defects and disorder, with single mode lasing even at conditions high above the laser threshold. RESULTS We demonstrate that topological insulator lasers are theoretically possible and experimentally feasible. We consider two configurations involving planar arrays of coupled active resonators. The first is based on the Haldane model, archetypical for topological systems. The second model, geared toward experiment, constitutes an aperiodic array architecture creating an artificial magnetic field. We show that by introducing saturable gain and loss, it is possible to make these systems lase in a topological edge state. In this way, the lasing mode exhibits topologically protected transport; the light propagates unidirectionally along the edges of the cavity, immune to scattering and disorder, unaffected by the shape of the edges. Moreover, we show that the underlying topological properties not only make the system robust to fabrication and operational disorder and defects, they also lead to a highly efficient single mode lasing that remains single mode even at gain values high above the laser threshold. The figure describes the geometry and features of a topological insulator laser based on the Haldane model while adding saturable gain, loss, and an output port. The cavity is a planar honeycomb lattice of coupled microring resonators, pumped at the perimeter with a lossy interior. We show that under these conditions, lasing occurs at the topological edge mode, which has unidirectional flux and is extended around the perimeter with almost uniform intensity. The topological cavities exhibit higher efficiency than the trivial cavity, even under strong disorder. For the topological laser with a small gap, the topological protection holds as long as the disorder level is smaller than the gap size. DISCUSSION The concept of the topological insulator laser alters current understanding of the interplay between disorder and lasing, and opens exciting possibilities at the interface of topological physics and laser science, such as topologically protected transport in systems with gain. We show here that the laser system based on the archetypal Haldane model exhibits topologically protected transport, with features similar to those of its passive counterpart. This behavior means that this system is likely to have topological invariants, despite the nonhermiticity. Technologically, the topological insulator laser offers an avenue to make many semiconductor lasers operate as one single mode high power laser. The topological insulator laser constructed from an aperiodic array of resonators was realized experimentally in an all dielectric platform, as described in the accompanying experimental paper by Bandres et al. Topological insulator laser based on the Haldane model and its efficiency. (A) Planar honeycomb lattice of coupled microring resonators pumped at the perimeter. The topological lasing mode has unidirectional flux with almost uniform intensity, which builds up as the mode circulates and drops when passing the output coupler. (B) Slope efficiency (in arbitrary units) versus disorder strength for three cases differing only in the Haldane phase (of the next to nearest neighbor coupling) a topological laser with the maximum gap (blue; Haldane phase of p/2) one with a small topological gap (red; Haldane phase of p/8) and a topologically trivial laser with no gap (black; Haldane phase of 0) Topological insulators are phases of matter characterized by topological edge states that propagate in a unidirectional manner that is robust to imperfections and disorder. These attributes make topological insulator systems ideal candidates for enabling applications in quantum computation and spintronics. We propose a concept that exploits topological effects in a unique way: the topological insulator laser. These are lasers whose lasing mode exhibits topologically protected transport without magnetic fields. The underlying topological properties lead to a highly efficient laser, robust to defects and disorder, with single mode lasing even at very high gain values. The topological insulator laser alters current understanding of the interplay between disorder and lasing, and at the same time opens exciting possibilities in topological physics, such as topologically protected transport in systems with gain. On the technological side, the topological insulator laser provides a route to arrays of semiconductor lasers that operate as one single mode high power laser coupled efficiently into an output port.", "author_names": [ "Gal Harari", "Miguel A Bandres", "Yaakov Lumer", "Mikael C Rechtsman", "Yidong Chong", "Mercedeh Khajavikhan", "Demetrios N Christodoulides", "Mordechai Segev" ], "corpus_id": 206665715, "doc_id": "206665715", "n_citations": 380, "n_key_citations": 5, "score": 0, "title": "Topological insulator laser: Theory", "venue": "Science", "year": 2018 }, { "abstract": "We demonstrate a nonmagnetic topological insulator laser exhibiting topologically protected transport. The topological properties of the system give rise to single mode lasing, robustness against fabrication defects, and higher slope efficiencies compared to its trivial counterpart.", "author_names": [ "Miguel A Bandres", "Steffen Wittek", "Gal Harari", "Midya Parto", "Jinhan Ren", "Mordechai Segev", "Demetrios N Christodoulides", "Mercedeh Khajavikhan" ], "corpus_id": 125868905, "doc_id": "125868905", "n_citations": 41, "n_key_citations": 4, "score": 0, "title": "Topological Insulator Laser", "venue": "", "year": 2018 }, { "abstract": "We introduce a class of topological lasers based on the photonic Floquet topological insulator concept. The proposed system is realized as a truncated array of the lasing helical waveguides, where the pseudo magnetic field arises due to twisting of the waveguides along the propagation direction that breaks the time reversal symmetry and opens up a topological gap. When sufficient gain is provided in the edge channels of the array then the system lases into the topological edge states. Topological lasing is stable only in certain intervals of the Bloch momenta, that ensure a dynamic, but stable balance between the linear amplification and nonlinear absorption leading to the formation of the breathing edge states. We also illustrate topological robustness of the edge currents by simulating lattice defects and triangular arrangements of the waveguides.", "author_names": [ "Sergey K Ivanov", "Yiqi Zhang", "Yaroslav V Kartashov", "Dmitry V Skryabin" ], "corpus_id": 204950211, "doc_id": "204950211", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Floquet topological insulator laser", "venue": "", "year": 2019 }, { "abstract": "We describe the recent progress on topological insulator lasers, where we employed the fundamental concepts of topological insulators in the non Hermitian laser system, to force an array of many semiconductor (InGaAs) resonators to lock together and act as one coherent laser source.", "author_names": [ "Gal Harari", "Miguel A Bandres", "Steffen Wittek", "Midya Parto", "Demetrios N Christodoulides", "Mercedeh Khajavikhan", "Mordechai Segev" ], "corpus_id": 211059153, "doc_id": "211059153", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Topological Insulator Laser", "venue": "2019 24th Microoptics Conference (MOC)", "year": 2019 }, { "abstract": "We demonstrate a nonmagnetic topological insulator laser exhibiting topologically protected transport. The topological properties of the system give rise to single mode lasing, robustness against fabrication defects, and higher slope efficiencies compared to its trivial counterpart.", "author_names": [ "Miguel A Bandres", "Steffen Wittek", "Gal Harari", "Midya Parto", "Jinhan Ren", "Mordechai Segev", "Demetrios N Christodoulides", "Mercedeh Khajavikhan" ], "corpus_id": 51980029, "doc_id": "51980029", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Experimental Realization of Magnetic Free Topological Insulator Laser", "venue": "2018 Conference on Lasers and Electro Optics (CLEO)", "year": 2018 }, { "abstract": "We propose a practical design to implement of a topological insulator laser. Due to the topological protection, the topological laser maintains a high slope efficiency and single mode lasing even in the presence of defects and disorder.", "author_names": [ "Steffen Wittek", "Gal Harari", "Miguel A Bandres", "H Hodaei", "Midya Parto", "Parinaz Aleahmad", "Mikael C Rechtsman", "Yidong Chong", "Demetrios N Christodoulides", "Mercedeh Khajavikhan", "Mordechai Segev" ], "corpus_id": 29489137, "doc_id": "29489137", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Towards the experimental realization of the topological insulator laser", "venue": "2017 Conference on Lasers and Electro Optics (CLEO)", "year": 2017 }, { "abstract": "We present the fundamentals of the recently invented topological insulator lasers.", "author_names": [ "Mordechai Segev", "Miguel A Bandres", "Gal Harari", "Steffen Wittek", "Demetrios N Christodoulides", "Mercedeh Khajavikhan" ], "corpus_id": 52165410, "doc_id": "52165410", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Experimental Realization of Magnetic Free Topological Insulator Laser", "venue": "2018 IEEE Photonics Society Summer Topical Meeting Series (SUM)", "year": 2018 } ]

[ { "abstract": "Light Emitting Diodes (LED) are highly energy efficient and offer long life times for display applications. Long life and minimal energy consumption are often the most attractive advantages for electronic devices. Because LEDs are based on compound semiconductors, which explore the direct transition between the conduction and valance band edges, thermal energy loss can be minimized during operation. However, even though these types of LEDs are based on direct transition type semiconductors, thermal energy is still emitted during operation owing to forward conduction and reverse leakage currents. This research proposes capturing this energy loss through thermoelectric module based energy recycling methods to improve the energy efficiency of LED applications, achieving savings of up to 18% Additional analysis was performed on high power LED sources resulting in the manufacture of a high power LED light grid system.", "author_names": [ "Jae-Hoon Ji", "Jinhwan Kim", "Gaehun Jo", "Min-Young Park", "Jihye Kang", "Masao Kamiko", "J G Ha", "S M Koo", "Junhee Hong", "Jung-Hyuk Koh" ], "corpus_id": 199452496, "doc_id": "199452496", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Possibility of Thermal Energy Recycling Based Light Emitting Diodes Grid System.", "venue": "Journal of nanoscience and nanotechnology", "year": 2020 }, { "abstract": "In this study, emitted light energy and the recycling of thermal energy from the arrays of a light emitting diode system were investigated. A light grid system is composed of the array of high power LED chips, thermoelement and heat sink. High power LED source has an advantage of high luminous efficiency, which combined with wasted thermal energy. Thermal energy loss can be regarded wasted energy. However, this wasting thermal energy can be effectively converted to the electrical energy from thermoelement and heat sink of a light grid system. By introducing the light grid system, the optical energy and thermal energy can be more effectively managed. In particular, we have intensively studied energy conversion efficiency of light grid system and energy harvesting characteristic through thermal energy.", "author_names": [ "Jae-Hoon Ji", "Gaehun Jo", "Junhee Hong", "Jung-Hyuk Koh" ], "corpus_id": 53714550, "doc_id": "53714550", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Energy Harvesting Through Wasted Thermal Energy by Light Grid Sources.", "venue": "Journal of nanoscience and nanotechnology", "year": 2019 }, { "abstract": "The advantages of light emitting diodes (LEDs) over previous light sources and their continuous spread in lighting applications is now indisputable. Still, proper modelling of their lifespan offers additional design possibilities, enhanced reliability, and additional energy saving opportunities. Accurate and rapid multi physics system level simulations could be performed in Spice compatible environments, revealing the optical, electrical and even the thermal operating parameters, provided, that the compact thermal model of the prevailing luminaire and the appropriate elapsed lifetime dependent multi domain models of the applied LEDs are available. The work described in this article takes steps in this direction in by extending an existing multi domain LED model in order to simulate the major effect of the elapsed operating time of LEDs used. Our approach is based on the LM 80 08 testing method, supplemented by additional specific thermal measurements. A detailed description of the TM 21 11 type extrapolation method is provided in this paper along with an extensive overview of the possible aging models that could be used for practice oriented LED lifetime estimations.", "author_names": [ "Janos Hegedus", "Gusztav Hantos", "Andras Poppe" ], "corpus_id": 225556756, "doc_id": "225556756", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Lifetime Modelling Issues of Power Light Emitting Diodes", "venue": "", "year": 2020 }, { "abstract": "Industrial scale catalytic chemical synthesis demands both high reaction rates and high product yields. In exothermic chemical reactions, these conflicting objectives require a complex balance of optimized catalysts, high temperatures, high pressures, and multiple recycling steps, as in the energy intensive Haber Bosch process for ammonia synthesis. Here we report that illumination of a conventional ruthenium based catalyst produces ammonia with high reaction rates and high conversion yields. Indeed, using continuous wave light emitting diodes that simulate concentrated solar illumination, ammonia is copiously produced without any external heating or elevated pressures. The possibility of nonthermal plasmonic effects are excluded by carefully comparing the catalytic activity under direct and indirect illumination. Instead, thermal gradients, created and controlled by photothermal heating of the illuminated catalyst surface, are shown to be responsible for the high reaction rates and conversion yields. This nonisothermal environment enhances both by balancing the conflicting requirements of kinetics and thermodynamics, heralding the use of optically controlled thermal gradients as a universal, scalable strategy for the catalysis of many exothermic chemical reactions.", "author_names": [ "Xueqian Li", "Xiao Zhang", "Henry O Everitt", "Jie Liu" ], "corpus_id": 73431393, "doc_id": "73431393", "n_citations": 38, "n_key_citations": 2, "score": 0, "title": "Light Induced Thermal Gradients in Ruthenium Catalysts Significantly Enhance Ammonia Production.", "venue": "Nano letters", "year": 2019 }, { "abstract": "An LED cooling system that uses a micro tube water cooling device is studied experimentally and a heat transfer model that uses a finite element method is numerically analyzed. In this experiment, the micro screw tube system achieves better thermal management and the heat created by the LEDs is effectively dissipated. It is experimentally found that the effect of thermal dissipation occurs by recycling water in the LEDs' light assemblies are in reasonable agreement. Introduction High power light emitting diodes (LEDs) which depend on the semiconductor material to emit the light have been extensively studied in recent years. LEDs with greatly improved energy efficiency are used not only as low energy indicators, but also as replacements for traditional light sources, in general lighting and automotive lighting [1 3] Recently, numerous reports have concerned heat removal from LEDs to allow better LED thermal management, especially with reference to package configuration and the materials used for substrates and heat sinks. There have been trials with an ultra bright LED module, a LED based spot module, multi walled carbon nanotubes, interface thermal materials, carbon black and a piezoelectric fan, as well as a thermal resistance model [4 6] To further investigate an effective cooling system and obtain optimum cooling performance in a LED array system, the natural convection in such a system requires special consideration, and a numerical model is considered. In this study, a cooling system with a micro screw tube and LED arrays uses red, green and blue LED in the white LED source. A new heat cooling system that uses a micro screw tube water cooling device is considered and finite element analysis (FEM) is implemented to solve the problem of thermal management in high power LED lighting experiments and to determine the ideal spectral power distribution of white LED lamps, in order to improve the color. This study also determines the feasibility of a micro tube water cooling system, using FEM algorithms for the thermal management of high power LED's.", "author_names": [ "Ming-der Jean", "Guofu Lian" ], "corpus_id": 73654856, "doc_id": "73654856", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Prediction and Thermal Management Analysis of LED Light Assemblies Using Finite Element Method", "venue": "", "year": 2017 }, { "abstract": "Organic light emitting diodes (OLEDs) have been the focus of intense study since the late 1980s, when the low voltage organic electroluminescence in small organic molecules such as Alq3, and large organic molecules such as polymers (PPV) was reported. Since that time, research has continued to demonstrate the potential of OLEDs as viable systems for displays and eco friendly lighting applications. OLEDs offer full colour display, reduced manufacturing cost, larger viewing angle, more flexible, lower power consumption, better contrast, slimmer, etc. which help in replacing the other technologies such as LCD. The operation of OLEDs involves injection of charge carriers into organic semiconducting layers, recombination of charge carriers, formation of singlet and triplet excitons, and emission of light during decay of excitons. The maximum internal quantum efficiency of fluorescent OLEDs consisting of the emissive layer of fluorescent organic material is 25% because in this case only the 25% singlet excitons can emit light. The maximum internal quantum efficiency of phosphorescent OLEDs consisting of the emissive layer of fluorescent organic material mixed with phosphorescent material of heavy metal complexes such as platinum complexes, iridium complexes, etc. is nearly 100% because in this case both the 25% singlet excitons and 75% triplet excitons emit light. Recently, a new class of OLEDs based on thermally activated delayed fluorescence (TADF) has been reported, in which the energy gap between the singlet and triplet excited states is minimized by design, thereby promoting highly efficient spin up conversion from non radiative triplet states to radiative singlet states while maintaining high radiative decay rates of more than 106 decays per second. These molecules harness both singlet and triplet excitons for light emission through fluorescence decay channels and provides an intrinsic fluorescence efficiency in excess of 90 per cent and a very high external electroluminescence efficiency of more than 19 per cent, which is comparable to that achieved in high efficiency phosphorescence based OLEDs.The OLED technology can be used to make screens large enough for laptop, cell phones, desktop computers, televisions, etc. OLED materials could someday be applied to plastic and other materials to create wall size video panels, roll up screens for laptops, automotive displays, and even head wearable displays. Presently, the OLEDs are opening up completely new design possibilities for lighting in the world of tomorrow whereby the offices and living rooms could be illuminated by lighting panels on the ceiling. The present paper describes the salient features of OLEDs and discusses the applications of OLEDs in displays and solid state lighting devices. Finally, the challenges in the field of OLEDs are explored. Contents of Paper", "author_names": [ "Vivek Kumar Chandra", "Belani P Chandra", "Piyush Jha" ], "corpus_id": 136645107, "doc_id": "136645107", "n_citations": 7, "n_key_citations": 1, "score": 0, "title": "Organic Light Emitting Diodes and their Applications", "venue": "", "year": 2014 }, { "abstract": "Abstract Nocturnal lighting systems account for 20% of the total global electricity consumption. The aim of this paper is to investigate and compare the following two street lighting technologies in Lebanon from an environmental perspective: i) traditional grid connected system and ii) solar stand alone system. Life Cycle Assessment (LCA) is the methodology used to assess and compare the potential environmental impacts of the two systems from cradle to grave, i.e. from the raw material extraction until the end of life product stages. Two end of life scenarios are modeled: landfilling and recycling. The SimaPro software is used for modeling the Life Cycle Inventory and the IMPACT 2002 method is used for the Life Cycle Impact Assessment. The traditional system includes a steel pole, a High Pressure Sodium lamp, and aluminum cables. The stand alone solar system includes a steel pole, a Light Emitting Diode lamp, a photovoltaic panel, a valve regulated acid battery, a controller, a dimmer, and copper cables. Results show that the traditional system has less environmental impacts than the solar stand alone system when considering the life cycle stages from the raw material extraction to the production phase only. This is mainly due to the important environmental impacts of the lead and electronics used in the solar system. However, this difference is compensated during the entire life cycle from the raw material extraction to the end of life because the traditional system consumes a significant amount of energy from the Lebanese electricity grid during the use phase. The grid mostly relies on thermal power plants, imported fuel, and diesel generators. The results show that the solar system has less overall environmental impacts than the traditional system for both landfilling and recycling scenarios. In particular, it is shown that the recycling scenario for the solar system results in positive impacts on the environment.", "author_names": [ "Scarlett Tannous", "Rima Manneh", "Hassan A Harajli", "Henri El Zakhem" ], "corpus_id": 158946827, "doc_id": "158946827", "n_citations": 21, "n_key_citations": 1, "score": 0, "title": "Comparative cradle to grave life cycle assessment of traditional grid connected and solar stand alone street light systems: A case study for rural areas in Lebanon", "venue": "", "year": 2018 }, { "abstract": "Author(s) Chou, Shu Yu Advisor(s) Pei, Qibing Abstract: According to recent research reports, the global market for display and lighting products is expected to grow to 169.17 billion USD by the year 2022. Display technologies include the light emitting diode (LED) liquid crystal display (LCD) organic light emitting diode (OLED) quantum dot light emitting diode (QDLED) and electronic paper display (EPD) whereas LEDs have been the dominant lighting solution in the past two decades due to their long lifetime and use of non hazardous materials. However, the growth in revenue for LED technology is predicted to slow down due to the advancement in OLED technology. OLEDs are known to be more energy efficient, have higher picture quality, and are more lightweight than LEDs. The bottleneck for OLEDs is their high production cost, which restrains it from the mass market. Fortunately, the development of conjugated polymer emitters shifts the manufacturing process from vacuum thermal evaporation to a solution processed methodology (i.e. ink jet printing, roll to roll printing, screen printing, etc. which is much more cost effective. The resulting OLED, also referred to as a polymer light emitting diode (PLED) shows enormous potential in the future of display technologies. Alongside the PLED, a new class of solution processable emitters, the organometal halide perovskite, has also shown promising performance in lighting applications. Despite their advantages, solution processed emitters have also shown lower device performance when compared to thermal vapor evaporated OLEDs. Due to the limitation of solution processed materials to withstand the solvent attack from advancing layers, solution processed light emitting devices usually have overly simple structures; this results in poor device performance, which can be attributed to the imbalance of charge injection. This dissertation focuses on improving the efficiency and stability of light emitting devices based on conjugated polymer emitters and organometal halide perovskite emitters by employing novel device architectures. In addition, based on the beneficial characteristics of the perovskite and polymer blend film, multifunctional devices including light emitting touch responsive devices and stretchable perovskite light emitting diodes are also demonstrated here. To begin, a white conjugated polymer emitter was applied on a flexible silver nanowire (AgNW) nanoparticle composite electrode, which resulted in a high out coupling efficiency with a 95% enhancement. The flexible nanocomposite electrode was made with silver nanowire electrode and barium strontium titanate (BST) nanoparticles. The high out coupling efficiency is achieved by replacing the ITO electrode with AgNW and by incorporating BST nanoparticles. Replacement of the ITO avoids light trapping inside the ITO caused by the mismatch of the refractive index, and the BST nanoparticles serve as the light scattering center that changed the path of the trapped light inside the substrate. The use of white conjugated polymer emitters on the light extraction substrate demonstrates a means to fabricate high efficiency flexible PLEDs with low fabrication cost. The white PLED achieved an external quantum efficiency of 27.3% The white conjugated polymer emitter was also used in a new type of optoelectronic device, the organic light emitting transistor (OLET) The white OLET combines both phosphorescent PLED and a transistor with a highly capacitive electrolyte dielectric material. By varying the gate potential, the luminance of the white OLET could be modified from 0.1 to 10,000 cd/m2. This work reveals the possibility of achieving a cost effective active matrix display based on solution processed materials and a simple device structure. Next, the organometal halide perovskite emitter is introduced. In one application, it was used to demonstrate a light emitting touch responsive device (LETD) which could provide instantaneous visualization of pressure mapping. The new LETD incorporates perovskite polymer composite film as the emitter and a flexible AgNW polyurethane as the top electrode. The perovskite LETD emitted an intense green luminescence when a local pressure was applied on the AgNW polyurethane due to the formation of a Schottky contact between the AgNW and the perovskite emissive layer. The fabrication of the perovskite LETD was simple and based on an all solution processed procedure.I also used the perovskite emitter to achieve a stretchable perovskite light emitting diode (PeLED) The PeLED integrates an intrinsically stretchable perovskite emissive layer and a stretchable AgNW polyurethane composite electrode. The stretchable perovskite emissive layer incorporates polyethylene glycol diacrylate (PEG) siliconized acrylate (PDMS) and methylammonium lead bromide. The PEG polymer helps to control the perovskite grain size and achieve a uniform perovskite grain film, while the PDMS polymer serves as the elastic connection that holds the film together and provides stretchability to the film. The composite electrode, AgNW polyurethane, provides high transparency, high conductivity, and high stretchability. With these elements combined, the PeLED could be stretched up to 60% strain while displaying a green electroluminescence. Both conjugated polymer emitters and organometal halide perovskite emitters have been successfully demonstrated in various light applications as a proof of concept. A highly efficient PLED was achieved by employing nanoparticles in the substrate to scatter the trapped light into the air. In addition, by adjusting the three terminal system to a suitable bias condition, the device luminance increased drastically due to the balance of electrons and holes in the OLET device. A robust and stable perovskite emissive layer was achieved by incorporating a PEO polymer, and an LETD was created that enables instantaneous pressure mapping. By adding an elastic polymer into the perovskite, a stretchable PeLED was also demonstrated. The results verify the potential of both conjugated polymer emitters and perovskite emitters for large scale, low cost lighting applications and for commercial use.", "author_names": [ "Shu-Yu Chou" ], "corpus_id": 217840244, "doc_id": "217840244", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solution Processed Polymer and Perovskite Emitters for Novel Light Emitting Applications", "venue": "", "year": 2017 }, { "abstract": "This paper highlights the benefits and possible drawbacks of a DC based lighting infrastructure for powering Light Emitting Diode (LED) lamps. It also evaluates the efforts needed for integrating the so called smart lighting and other sensor/actuator based control systems, and compares existing and emerging solutions. It reviews and discusses published work in this field with special focus on the intelligent DC based infrastructure named EDISON that is primarily dedicated to lighting, but is applicable to building automation in general. The EDISON \"PowerLAN\" consists of a DC based infrastructure that offers telecommunication abilities and can be applied to lighting retrofitting scenarios for buildings. Its infrastructure allows simple and efficient powering of DC oriented devices like LED lamps, sensors and microcontrollers, while offering a wired communication channel. This paper motivates the design choices for organizing DC lighting grids and their associated communication possibilities. It also shows how the EDISON based smart lighting solution is evolving today to include new communication technologies and to further integrate other parts of building management solutions through the OneM2M (Machine to Machine) service bus.", "author_names": [ "P Ramya", "M Praveen Kumar" ], "corpus_id": 214754563, "doc_id": "214754563", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An Energy Efficient Dc Lighting Grid Using IOT", "venue": "", "year": 2018 }, { "abstract": "Rising population numbers place ever increasing demands on energy resources. A large percentage of the worldwide energy production is reserved for the generation of electricity and a significant portion of the electrical energy generation is used for illumination purposes. At the same time, people demand brighter light sources that provide better light quality. The luminaire of today is not just a simple lamp, but a complex, intelligent piece of technology designed for a specific purpose. This doctoral dissertation aims to provide a link between the theoretical universe surrounding the physics of electromagnetic radiation and the practical illumination world. A theoretical framework presents the physical properties of light and connects, through the human visual system, to a number of perceptual models. Based on these perceptual models, the colourimetric qualities of an illumination spectrum are analysed and a theoretical framework that aims to optimise the balance between colour fidelity and energy efficiency is proposed. The result of this optimisation is a spectrum that needs to be implemented into a light source. Recent advancements in semiconductor technology led to the development of highly efficient light emitting diodes. The monochromatic nature of these light sources offers the possibility of creating a spectrally tuneable luminaire that is able to reproduce these optimised illumination spectra. A fully integrated spectrally tuneable light engine combines knowledge on characterising and driving LEDs, optical design and thermal management. Each group of monochromatic LEDs needs a variable current source that ensures predictable behaviour regardless of their dimming level or temperature. An advanced optical solution enables efficient light extraction from the LEDs, provides excellent luminance and chroma homogenisation and, finally, delivers a suitable beam pattern for the intended illumination application. Proper thermal management establishes sufficient heat extraction to guarantee low semiconductor temperatures. Finally, the LED light engines created during this doctoral research are incorporated into three spectrally tuneable illumination devices, each designed for a specific purpose. A set of spectrally tuneable downlights installed in the laboratories of the lighting group of the Catalonia Institute for Energy Research (IREC) in Barcelona, Spain and the department of neuroscience of the University of Newcastle in the United Kingdom serves as a valuable tool for experiments that evaluate both physical and psychovisual properties of selected illumination spectra. A compact spotlight, used during the \"Making Colour\" exhibition of the National Gallery in London, is optimised to provide a set of specific illumination spectra to illuminate art reproductions. Lastly, a high power luminaire was designed to generate specialised spectra to irradiate greenhouse plants, steering their morphology and the production of plant specific compounds.", "author_names": [ "Wim Hertog" ], "corpus_id": 115505373, "doc_id": "115505373", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The design and implementation of a spectrally tuneable led based light sourde: towards a new era of intelligent illumination", "venue": "", "year": 2017 } ]

[ { "abstract": "Photovoltaic panels have a limited lifespan and estimates show large amounts of solar modules will be discarded as electronic waste in a near future. In order to retrieve important raw materials, reduce production costs and environmental impacts, recycling such devices is important. Initially, this article investigates which silicon photovoltaic module's components are recyclable through their characterization using X ray fluorescence, X ray diffraction, energy dispersion spectroscopy and atomic absorption spectroscopy. Next, different separation methods are tested to favour further recycling processes. The glass was identified as soda lime glass, the metallic filaments were identified as tin lead coated copper, the panel cells were made of silicon and had silver filaments attached to it and the modules' frames were identified as aluminium, all of which are recyclable. Moreover, three different components segregation methods have been studied. Mechanical milling followed by sieving was able to separate silver from copper while chemical separation using sulphuric acid was able to detach the semiconductor material. A thermo gravimetric analysis was performed to evaluate the use of a pyrolysis step prior to the component's removal. The analysis showed all polymeric fractions present degrade at 500 degC.", "author_names": [ "Pablo Ribeiro Dias", "Mariana Goncalves Benevit", "Hugo Marcelo Veit" ], "corpus_id": 42326009, "doc_id": "42326009", "n_citations": 29, "n_key_citations": 3, "score": 0, "title": "Photovoltaic solar panels of crystalline silicon: Characterization and separation", "venue": "Waste management research the journal of the International Solid Wastes and Public Cleansing Association, ISWA", "year": 2016 }, { "abstract": "With the increasing implementation of solar photovoltaic (PV) systems, comprehensive methods and tools are required to dynamically assess their economic and environmental costs and benefits under varied spatial and temporal contexts. This study integrated system dynamics modeling with life cycle assessment and life cycle cost assessment to evaluate the cumulative energy demand, carbon footprint, water footprint, and life cycle cost of residential grid connected (GC) and standalone (SA) solar PV systems. The system dynamics model was specifically used for simulating the hourly solar energy generation, use, and storage during the use phase of the solar PVs. The modeling framework was then applied to a residential prototype house in Boston, MA to investigate various PV panel and battery sizing scenarios. When the SA design is under consideration, the maximum life cycle economic saving can be achieved with 20 panels with no battery in the prototype house, which increases the life cycle economic savings by 511.6% as compared to a baseline system sized based upon the engineering rule of thumb (40 panels and 40 batteries) yet decreases the demand met by 55.7% However, the optimized environmental performance was achieved with significantly larger panel (up to 300 units) and battery (up to 320 units) sizes. These optimized configurations increase the life cycle environmental savings of the baseline system byup to 64.6% but significantly decrease the life cycle economic saving by up to 6868.4% There is a clear environmental and economic tradeoff when sizing the SA systems. When the GC system design is under consideration, both the economic and environmental benefits are the highest when no battery is installed, and the benefits increase with the increase of panel size. However, when policy constraints such as limitations/caps of grid sell are in place, tradeoffs would present as whether or not to install batteries for excess energy storage.", "author_names": [ "Mingcheng Ren", "Clayton R Mitchell", "Weiwei Mo" ], "corpus_id": 214644751, "doc_id": "214644751", "n_citations": 10, "n_key_citations": 0, "score": 1, "title": "Dynamic life cycle economic and environmental assessment of residential solar photovoltaic systems.", "venue": "The Science of the total environment", "year": 2020 }, { "abstract": "T recent thrust toward utilizing nanomaterials for light energy conversion has brought noticeable success in the field of thin film photovoltaics (PV) In fact, thin film solar cells have already demonstrated themselves to be a viable commercial technology. Furthermore, the recent success of achieving more than 20% power conversion efficiency with organic inorganic lead halide perovskites (http:/www.nrel. gov/ncpv/images/efficiency_chart.jpg) has led the speculation that these devices may provide the transformative leap needed to drive widespread adaptation of thin film PV. Although the photovoltaic efficiency of thin film solar cells is steadily increasing, the price of these panels continues to drop at the same time, bringing PV technology closer to grid power. Continued reduction in the panel, installation, and balance of systems costs of PV could soon transform an imagined ideal into reality; solar energy may be able to directly compete with, and even outcompete, energy from fossil fuels. Semiconductor assisted hydrogen production and reduction of CO2 are being projected as attractive approaches for storing solar energy in the form of fuels. Despite the successes achieved in recent years in thin film photovoltaics, the story is markedly different for solar fuel generation by semiconductor assisted photocatalysis (Scheme 1) By integrating two perovskite solar cells with a relatively modest solar to electric power conversion efficiency of 15.7% in series with an electrolyzer, Luo and coworkers were able to split water with an overall efficiency of over 12% However, designing a cost effective stand alone photocatalytic reactor with efficiency in a similar range remains an ambitious goal. The first photocatalytic water splitting was introduced by Honda and Fujishima in 1972. Yet, despite over four decades of photocatalytic research, a practically compatible technology does not seem to be a near term reality. Progress is lagging in terms of material deployment as well as truly scalable devices. It is now generally accepted that a single light absorber system will likely not overcome all the barriers in photocatalytic water splitting. Given the 1.23 V thermodynamic barrier for water splitting and the overpotential required for the water oxidation at the photoanode and/or reduction of H at the photocathode, one would require a semiconductor with bandgap energy of 1.5 to 2.0 eV to drive the photocatalytic process efficiently with visible light. To date, no single semiconductor system has been identified that can continuously produce hydrogen without the aid of an external bias or use of sacrificial electron donor. New strategies to utilize multijunction tandem devices and photocatalysts assembled with a Z scheme show promise in bringing about transformative change in the field of photocatalysis; however, it is important that the scientific community realize the limitations inherent in implementing proton coupled electron transfer processes in photocatalytic systems. Nevertheless, given the current thrust in funded research for solar fuel production, one can feel optimistic that continued advances could make it as effective as PV technology in the near future. The two Perspectives in this issue focus on the importance of metal oxide semiconductor interfaces in quantum dot sensitized solar cells and photocatalysis as a means to synthesize useful chemicals. Tian and Cao discuss how the large surface area of TiO2 and ZnO nanostructures, which facilitates QD loading, also provides an easy pathway for charge recombination and abundant surface defects, limiting overall power conversion efficiency. New approaches for surface modification of the metal oxide nanostructure and recent advances in improving the photoconversion efficiency are discussed. Augugliaro et al. present photocatalytic approaches for the conversion of noxious chemicals into high value chemical products. Although a majority of the published work in this area relates to the photocatalytic remediation of undesired compounds, the controlled photocatalytic conversion into desirable chemical products is also of importance. Dimethyl carbonate is also being considered as an alternative green organic solvent to enhance the solubility of organic compounds, thus overcoming the limitation posed by the low water solubility. The recovery of products is still a challenge for advancing this technology toward industrial applications. Prashant V. Kamat* University of Notre Dame, Notre Dame, Indiana 46556, United States Jeffrey A. Christians Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States", "author_names": [ "Prashant V Kamat", "Jeffrey A Christians" ], "corpus_id": 40091215, "doc_id": "40091215", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Solar Cells versus Solar Fuels: Two Different Outcomes.", "venue": "The journal of physical chemistry letters", "year": 2015 }, { "abstract": "Solar photovoltaic systems have become one of the most popular topics in the water management industry. Moreover, irrigation networks are water and energy hungry, and utility managers are likely to adapt water consumption (and consequently energy demand) to the hours in which there is energy availability. In countries such as Spain (with high irradiance values) solar energy is an available green alternative characterised by zero electricity costs and significantly lower environmental impact. In this work, several types of irrigation scheduled programmes (according to different irrigation sectors) that minimise the number of photovoltaic solar panels to be installed are studied; moreover, the effects of the variable costs linked to energy (energy and emissions costs) are presented. Finally, the effect of incorporating batteries for storing energy to protect the system against emergencies, such as unfavourable weather, is proposed. The irrigation hours available to satisfy water demands are limited by sunlight; they are also limited by the condition that the irrigation schedule type has to be rigid (predetermined rotation) and that the pressure at any node has to be above minimum pressure required by standards. A real case study is performed, and the results obtained demonstrate that there is no universal solution; this is because the portfolio of alternatives is based on investments for purchasing equipment at present and also on future energy savings (revenues) Apart from these two values, there is an economic value (equivalent discontinuous discount rate) which also influences the final results.", "author_names": [ "Miguel Pardo", "Juan Manzano", "Javier Valdes-Abellan", "Ricardo Cobacho" ], "corpus_id": 125178232, "doc_id": "125178232", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "Standalone direct pumping photovoltaic system or energy storage in batteries for supplying irrigation networks. Cost analysis.", "venue": "The Science of the total environment", "year": 2019 }, { "abstract": "A study was performed based on the design of a new wastewater treatment plant (WWTP) to be built in Weesp, The Netherlands (about 46,000 Population Equivalents (PE) The conventional activated sludge plant was considered among the alternatives, with and without primary sedimentation. This pre treatment technique is considered a sustainability measure as it improves the energy balance of the WWTP. However, at the same time, the question arose about the cost effectiveness of this measure. The scope of the study was to assess whether other sustainability measures (like solar panels) can realise the same level of sustainability with lower costs. The outcome of the study indeed shows that, for a new WWTP, it is considerably cheaper to avoid primary sedimentation and focus on other measures like solar panels instead. This appeared not only to be the case for the scale of WWTP Weesp, but also for WWTPs with capacities higher than 500,000 PE. For existing WWTPs with primary sedimentation, the choice can be different as customisation is necessary.", "author_names": [ "Sara Giorgi", "Berend Aldert Huigo Reitsma", "H J F van Fulpen", "Robert Berg", "M Bechger" ], "corpus_id": 53423837, "doc_id": "53423837", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Primary sedimentation as a sustainability measure for newly built municipal wastewater treatment plants: too expensive?", "venue": "Water science and technology a journal of the International Association on Water Pollution Research", "year": 2018 }, { "abstract": "Solar photovoltaic based microgrids and nanogrids are becoming very popular in many developing countries due to lowering panels and balance of system costs. While many nanogrids (isolated houses with solar generation or small integrated community with very low power provisioning) have been popular, the need for interconnecting these for bidirectional power transactions is growing. This allows efficient resource utilization due to usage diversity. This work therefore analyses a 12/24 V to 380 V isolated boost converter suitable for many DC microgrid applications with bidirectional power flow requirements. The proposed converter has been evaluated for operation under different microgrid scenarios requiring an efficient bidirectional flow of power between a low voltage nanogrid (single house or a close neighborhood) and a high voltage microgrid (which interconnects several nanogrids) The converter is tested up to 250W with power flow in each direction with satisfactory results.", "author_names": [ "Ch Dost Muhammad Cheema", "Khawaja Samad Shah", "Hassan Abbas Khan", "Nauman Ahmad Zaffar" ], "corpus_id": 23935605, "doc_id": "23935605", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Design and analysis of isolated boost converter for microgrid applications", "venue": "IECON 2017 43rd Annual Conference of the IEEE Industrial Electronics Society", "year": 2017 }, { "abstract": "The share of renewable energy sources in energy production is growing steadily. Domestic homes can be equipped with solar panels, micro combined heat and power systems, batteries, and they can become adaptive consumers. They can also deliver energy to the grid and react to the energy supply. This paper presents a hybrid simulation approach for the analysis of a grid of domestic homes equipped with different technological options with respect to efficiency and costs. For energy storage and energy flows the system dynamics modeling paradigm is used whereas control decisions are modeled as statecharts. The highly intermittent solar irradiation and also the electric power and heat demands are implemented as stochastic models. The component based design allows for quick creation of new case studies. As examples, different homes with batteries, micro combined heat and power systems, or energy carrier carbazole as energy storage are analyzed.", "author_names": [ "Peter Bazan", "Reinhard German" ], "corpus_id": 16351124, "doc_id": "16351124", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Hybrid simulation of renewable energy generation and storage grids", "venue": "Proceedings Title: Proceedings of the 2012 Winter Simulation Conference (WSC)", "year": 2012 }, { "abstract": "In renewable energy systems based on fuel cells, these can suffer deterioration derived from start up/stop cycles, load changes or run time operation. This paper analyses the viability of using a fuel cell system built from a high power single stack or from multiple low medium power stacks under fixed or variable power operation in a renewable energy system which includes Solar Panels, Wind turbines, Polymer Electrolyte Fuel Cells, Batteries and Electrolyzer. The aim of this comparison is to improve the system efficiency. To get this target, technical and economical optimization parameters have been taken into account in order to improve the fuel cell system lifetime, reduce operation and maintenance costs guarantying the power balance, the hydrogen stock and keeping the restrictions of the batteries' state of charge. For this purpose, a simulator has been developed in order to test different configurations of the fuel cell system. The configurations analysed are (A) a modular PEFC based on two 3.4 kW stacks working at 2 kW every stack, (B) a single 6.8 kW stack working at 4 kW power, (C) a single 6.8 kW stack working at variable power and (D) a single 6.8 kW stack working at two fixed levels (2 kW or 4 kW) depending on the demand.", "author_names": [ "Francisco Jose Vivas Fernandez", "A De las Heras", "F Segura", "Jose Manuel Andujar Marquez" ], "corpus_id": 3534899, "doc_id": "3534899", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Configuration of a Fuel Cell system. Clues to choose between a modular or single stack based design", "venue": "IECON 2016 42nd Annual Conference of the IEEE Industrial Electronics Society", "year": 2016 }, { "abstract": "Due to the integration of renewable energies, the electricity grid is confronted with new peak situations that are caused by the new power plants. Beside these threats new metering technologies combined with information systems enable new pricing options that were not affordable for retail customers before. This paper contributes to the field by combining demand charging incentives with a feed in tariff for photovoltaics. Demand charges are a broadly used pricing concept for large scale and industrial customers but are not used for retail customers yet. In a simulation we first of all show the impact of solar plants on the grid. Secondly, we simulate the shift in electricity demand caused by a demand charge for retail customers. Our simulation shows that the solar panels reduce the purchased quantity of electricity while leaving the maximum peak unchanged. This leads to reduced revenues for grid operators without changing the costs. This negative impact can be improved by the demand charge for retail customers.", "author_names": [ "Yannic Domigall", "Antonia Albani", "Robert Winter" ], "corpus_id": 35355471, "doc_id": "35355471", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Effects of demand charging and photovoltaics on the grid", "venue": "IECON 2013 39th Annual Conference of the IEEE Industrial Electronics Society", "year": 2013 }, { "abstract": "This study investigates the application of gravity gradient and aerodynamic torques in the attitude control and momentum management (ACMM) of the space station. Due to the large inertia and solar panels, environmental torque is significant enough in the ACMM in order to save fuel costs. Towards this end, the gravity gradient and the solar panels' aerodynamic models are established. The weighted state H controller is designed since the attitude control sub system is much slower than the momentum management sub system. Numerical results are shown to demonstrate the practicability of the environmental torque application and the effectiveness of the weighted state H technique.", "author_names": [ "Xingdan Wang", "Yu Yao", "Jian Xin Guo", "Kai Liu", "Yang Guo" ], "corpus_id": 38058621, "doc_id": "38058621", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Attitude control and momentum management of space station via weighted state H method", "venue": "Proceedings of the 33rd Chinese Control Conference", "year": 2014 } ]

[ { "abstract": "In this paper, closed loop control and boundary condition for continuous conduction mode and discontinuous conduction mode of nonisolated inverting Nx multilevel boost converter (MBC) are articulated. Inverting Nx MBC combines the features of classical boost converter and voltage multiplier to attain inverting N times higher voltage. Consequently, the inverting Nx MBC provides a viable solution for high voltage step up photovoltaic applications with low voltage rating reactive components and semiconductor devices. The control strategy with saturation limiter is employed to achieve highly stable voltage. The modes of operation, benefits of inverting Nx MBC, and key factors for the selection of semiconductor devices and sizing of the reactive components are discussed. Additionally, the effects of reactive components and semiconductor devices on the output voltage are examined. Experimental results of the developed circuit are presented to validate the design of converter, and effectiveness and robustness of the implemented control algorithm for different input and output side perturbations.", "author_names": [ "Atif Iqbal", "Mahajan Sagar Bhaskar", "Mohammad Meraj", "Sanjeevikumar Padmanaban", "Syed Rahman" ], "corpus_id": 155883583, "doc_id": "155883583", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Closed Loop Control and Boundary for CCM and DCM of Nonisolated Inverting Nx Multilevel Boost Converter for High Voltage Step Up Applications", "venue": "IEEE Transactions on Industrial Electronics", "year": 2020 }, { "abstract": "In fuel cell vehicles, the output voltage of the fuel cell source is typically much lower than the voltage required by the dc bus, and also this output voltage drops significantly as the output current increases. In order to match the output voltage of the fuel cell source to the dc bus voltage, a new dc dc boost converter with a wide input range and high voltage gain is proposed to act as the required power interface, which reduces voltage stress across the power devices and operates with an acceptable conversion efficiency. A prototype rated at 300 W/400 V has been developed and the maximum efficiency of the proposed converter was measured as 95.01% at 300 W. Experimental results are presented to validate the effectiveness of the proposed converter.", "author_names": [ "Yun Zhang", "Heyu Liu", "Jing Li", "Mark Sumner", "Changliang Xia" ], "corpus_id": 96431619, "doc_id": "96431619", "n_citations": 41, "n_key_citations": 4, "score": 0, "title": "DC DC Boost Converter With a Wide Input Range and High Voltage Gain for Fuel Cell Vehicles", "venue": "IEEE Transactions on Power Electronics", "year": 2019 }, { "abstract": "This article proposed a nonisolated symmetrical interleaved multilevel boost converter for high voltage microgrid applications. The proposed converter configuration is derived from the integration of a voltage multiplier (VM) circuit with the front end structure of the classical two phase interleaved converter. Moreover, equal voltage rating capacitors and diodes are suitable to design multiple stages of the proposed converter. The proposed converter can feed from two independent sources or single source in the interleaved approach. The continuous input current, high voltage gain, reduced voltage rating of capacitor (that causes reduction in cost) reduced components, and flexibility in number of sources make the proposed converter more attractive for renewable dc microgrid applications such as, photovoltaic (PV) system, fuel cell (FC) system, and hybrid PV FC system. Furthermore, the voltage gain of the converter can be increased by just adding similar stages of VM without preferring the high voltage rating capacitors and without disturbing the front end structure of the converter. Nonidealities are considered to analyze the proposed converter in a more practical way. The characteristics and operation of the proposed converter are discussed in this article with the continuous conduction mode and Discontinuous Conduction Mode boundary conditions. The design of the reactive components and selection of semiconductor devices are discussed. Additionally, the proposed converter is compared with recently proposed dc dc multilevel converters. To support the proposed work, simulation and experimental results are provided which shows a good agreement with the analytical approach.", "author_names": [ "Mahajan Sagar Bhaskar", "Mohammad Meraj", "Atif Iqbal", "Sanjeevikumar Padmanaban" ], "corpus_id": 202099411, "doc_id": "202099411", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Nonisolated Symmetrical Interleaved Multilevel Boost Converter With Reduction in Voltage Rating of Capacitors for High Voltage Microgrid Applications", "venue": "IEEE Transactions on Industry Applications", "year": 2019 }, { "abstract": "This paper proposes a fully integrated high conversion ratio dual output voltage boost converter (VBC) with maximum power point tracking (MPPT) circuits for low voltage energy harvesting. The VBC consists of two voltage generators that generate V_OUT1 and V_OUT2 V_OUT1 and V_OUT2 are three and nine times higher than the harvester's output V_IN respectively. V_OUT1 is used as a supply voltage for on chip application circuits while V_OUT2 is used as the charging voltage for a Li ion secondary battery. The VBC achieves a high voltage conversion ratio (max. x 9) and a high power conversion efficiency. The MPPT circuits control the operating frequencies of the CPs to extract maximum power at each output. The measurement results demonstrated that the circuit converted a 0.59 V input to a 1.41 V output with 75.8% efficiency when the output powers of V_OUT1 and V_OUT2 were 396 and 0 mW, respectively, and a 0.62 V input to a 4.54 V output with 49.1% efficiency when the output powers were 0 and 114 mW, respectively.", "author_names": [ "Toshihiro Ozaki", "Tetsuya Hirose", "Hiroki Asano", "Nobutaka Kuroki", "Masahiro Numa" ], "corpus_id": 8412005, "doc_id": "8412005", "n_citations": 41, "n_key_citations": 0, "score": 0, "title": "Fully Integrated High Conversion Ratio Dual Output Voltage Boost Converter With MPPT for Low Voltage Energy Harvesting", "venue": "IEEE Journal of Solid State Circuits", "year": 2016 }, { "abstract": "In this article a new Transformer and Switched Capacitor based Boost Converter (T SC BC) is proposed for high voltage/low current renewable energy applications. The proposed T SC BC is an original extension for DC DC boost converter which is designed by utilizing a transformer and switched capacitor (T SC) Photovoltaic (PV) energy is a fast emergent segment among the renewable energy systems. The proposed T SC BC combines the features of the conventional boost converter and T SC to achieve a high voltage conversion ratio. A Maximum Power Point Tracking (MPPT) controller is compulsory and necessary in a PV system to extract maximum power. Thus, a photovoltaic MPPT control mechanism also articulated for the proposed T SC BC. The voltage conversion ratio (Vo/Vin) of proposed converter is (1 k)(1 D) where, k is the turns ratio of the transformer and D is the duty cycle (thus, the converter provides 9.26, 13.88, 50/3 voltage conversion ratios at 78.4 duty cycle with k 1, 2, 2.6, respectively) The conspicuous features of proposed T SC BC are: (i) a high voltage conversion ratio (Vo/Vin) (ii) continuous input current (Iin) (iii) single switch topology; (iv) single input source; (v) low drain to source voltage (VDS) rating of control switch; (vi) a single inductor and a single untapped transformer are used. Moreover, the proposed T SC BC topology was compared with recently addressed DC DC converters in terms of number of components, cost, voltage conversion ratio, ripples, efficiency and power range. Simulation and experimental results are provided which validate the functionality, design and concept of the proposed approach.", "author_names": [ "Sanjeevikumar Padmanaban", "Mahajan Sagar Bhaskar", "Pandav Kiran Maroti", "Frede Blaabjerg", "Viliam Fedak" ], "corpus_id": 115753376, "doc_id": "115753376", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "An original transformer and switched capacitor (T SC) based extension for DC DC boost converter for high voltage/low current renewable energy applications: Hardware implementation of a new T SC boost converter", "venue": "", "year": 2018 }, { "abstract": "Due to the more vigorous regulations on carbon gas emissions and fuel economy, Fuel cell electric vehicles (FCEV) are becoming more popular in the automobile industry. This paper presents a neural network based maximum power point tracking (MPPT) controller for 1.26 kW proton exchange membrane fuel cell (PEMFC) supplying electric vehicle powertrain through a high voltage gain dc dc boost converter. The proposed neural network MPPT controller uses a radial basis function network (RBFN) algorithm for tracking the maximum power point of the PEMFC. High switching frequency and high voltage gain dc dc converters are essential for the propulsion of FCEV. In order to attain high voltage gain, a three phase high voltage gain interleaved boost converter is also designed for FCEV system. The interleaving technique reduces the input current ripple and voltage stress on the power semiconductor devices. The performance analysis of the FCEV system with RBFN based MPPT controller is compared with the fuzzy logic controller in MATLAB/Simulink platform.", "author_names": [ "K Jyotheeswara Reddy", "N Sudhakar" ], "corpus_id": 3458974, "doc_id": "3458974", "n_citations": 44, "n_key_citations": 0, "score": 0, "title": "High Voltage Gain Interleaved Boost Converter With Neural Network Based MPPT Controller for Fuel Cell Based Electric Vehicle Applications", "venue": "IEEE Access", "year": 2018 }, { "abstract": "In this paper, a new nonisolated high voltage gain boost converter is proposed. The proposed converter is constructed by adding an additional inductor to a conventional three level boost (TLB) converter. When compared with the conventional boost and TLB converters, the proposed converter can achieve higher voltage conversion ratio with reduced voltage and current stresses in the switches. In particular, the proposed converter can reduce the losses of active devices by reducing the current of the switch compared to conventional converters, thus, can achieve high efficiency. In addition, the proposed converter automatically balances the output voltages for an unbalanced load without the need for any additional control strategy or auxiliary circuit. A 2 kW prototype converter was built and tested to verify performances of the proposed converter.", "author_names": [ "Hyemin Kang", "Honnyong Cha" ], "corpus_id": 34632631, "doc_id": "34632631", "n_citations": 28, "n_key_citations": 1, "score": 0, "title": "A New Nonisolated High Voltage Gain Boost Converter With Inherent Output Voltage Balancing", "venue": "IEEE Transactions on Industrial Electronics", "year": 2018 }, { "abstract": "The need of dc dc switching converters for power supplies with high voltage gains has increased in the recent years due to new applications in areas as renewable energy systems, transportation, industrial, medical, and others. A quadratic boost converter is a useful topology to obtain a step up output voltage; however, a major drawback is the presence of a higher voltage stress over the active and passive switches. In this paper, a quadratic boost converter is combined with a voltage multiplier cell and an output filter to offer a high voltage gain converter with nonpulsating input and output currents. The expressions for the capacitor voltages and inductor currents are given, as well as the corresponding ripples that allow the proper design of the converter. The bilinear switched, nonlinear averaged and linear averaged models are derived such that the dynamical behavior of the converter is analyzed and used to design a control strategy. A step by step procedure is given to tune up a current mode controller. Experimental results are shown from a prototype, which delivers an output voltage of 220 V and an output power of 300 W. Step load changes between 20% and full load are applied to exhibit the robustness of switching regulator.", "author_names": [ "Jesus Leyva-Ramos", "R Mota-Varona", "Maria Guadalupe Ortiz-Lopez", "Luis Humberto Diaz-Saldierna", "Diego Langarica-Cordoba" ], "corpus_id": 28469263, "doc_id": "28469263", "n_citations": 44, "n_key_citations": 0, "score": 0, "title": "Control Strategy of a Quadratic Boost Converter With Voltage Multiplier Cell for High Voltage Gain", "venue": "IEEE Journal of Emerging and Selected Topics in Power Electronics", "year": 2017 }, { "abstract": "Purpose The paper aims to design of dual mode boost converter with integrated low voltage control circuit is introduced in this paper. The paper aims to discuss these issues. Design/methodology/approach The converter is operated either with LC filter or with charge pump circuit by the switch control. The control stage with error amplifier, comparator, and oscillator is designed with the supply voltage of 3.3 V and the operating frequency of 5.5 MHz. The compensator circuit exploits a pole compensation for a stable operation. Findings The simulation test in 0.35 mm CMOS process shows that the charge pump regulator and DC DC boost converter are accurately controlled with the variation of number of stages and duty ratio. The output voltage is obtained to be 6 15 V within the ripple ratio of 5 percent. Maximum power consumption is about 0.65 W. Originality/value This dual mode is useful in the converter with a wide load current variation. The advantage of the dual mode converter is that it can be used.", "author_names": [ "Jung-Woong Park", "Munkhsuld Gendensuren", "Ho-Yong Choi", "Nam-Soo Kim" ], "corpus_id": 111093079, "doc_id": "111093079", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "Integrated high voltage boost converter with LC filter and charge pump", "venue": "", "year": 2013 }, { "abstract": "An impedance network dc dc boost converter is developed in this letter. Compared to the conventional boost converter, it can reach a higher voltage gain with fewer diodes and a small duty cycle (smaller than 33% and, meanwhile, avoid instability caused by saturation of its inductors, whereas the conventional boost converters realize high voltage gains at rather large duty cycles (normally exceeding 50% resulting in saturation of inductors. Furthermore, it can well fulfill the stringent industrial requirements, particularly of renewable power systems. The proposed converter with continuous conduction modes is analyzed for different states of its components. Then, it is shown how to determine its various parameters. Finally, simulations and a 250 W prototype are conducted to verify the converter's effectiveness.", "author_names": [ "Guidong Zhang", "Herbert Ho-Ching Iu", "Bo Zhang", "Zhong Li", "Tyrone Lucius Fernando", "Si-Zhe Chen", "Yun Zhang" ], "corpus_id": 35512011, "doc_id": "35512011", "n_citations": 41, "n_key_citations": 4, "score": 0, "title": "An Impedance Network Boost Converter With a High Voltage Gain", "venue": "IEEE Transactions on Power Electronics", "year": 2017 } ]

[ { "abstract": "A current sense amplifier (CSA) based on a fully differential difference amplifier (FDDA) is introduced. A prototype was manufactured in a 0.18 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> bipolar, CMOS, DMOS (BCD) technology of Taiwan Semiconductor Manufacturing Company, Limited (TSMC) and characterized. The FDDA architecture offers several benefits regarding gain, bandwidth (BW) and noise performance and is well suited for low side phase current measurement (PCM) in modern electric engines. To achieve a high gain accuracy, an integrated resistive feedback, which offers a low frequency gain of more than 46 dB with a gain error of less than 1% and a 3 dB BW of approximately 2 MHz simulated and confirmed by measurements, is used. Hence, the circuit offers a higher measurement speed and sensitivity than the current state of the art devices. Furthermore, the manual offset reduction allows for an input offset in the low microvolt range, and the input referred noise is reduced to an input noise voltage of less than <inline formula> <tex math notation=\"LaTeX\"$30~\\mu \\text{V} /tex math>/inline formula> (rms) and a noise floor of <inline formula> <tex math notation=\"LaTeX\"{13}\\mathrm {nV} \\surd \\mathbf {Hz} /tex math>/inline formula> (above 30 kHz) This article describes the design including the top level structure, the distinct gain stages, the common mode feedback (CMFB) and the output buffer amplifier of the CSA in detail. Finally, a measurement with a noisy rectangular 1 mV, 500 kHz signal proves the great potential of the amplifier for low side PCM which is further compared with the state of the art commercial products and research results.", "author_names": [ "Christian D Matthus", "Simon Buhr", "Martin Kreissig", "Frank Ellinger" ], "corpus_id": 226751262, "doc_id": "226751262", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "High Gain and High Bandwidth Fully Differential Difference Amplifier as Current Sense Amplifier", "venue": "IEEE Transactions on Instrumentation and Measurement", "year": 2021 }, { "abstract": "Abstract This brief presents a novel compact CMOS Fully Differential Difference Amplifier (FDDA) structure suitable for extremely low voltage low power applications. Unlike the conventional FB DDAs that employ two differential pairs, the proposed structure employs one differential pair of multiple input bulk driven MOS transistor (MI BD MOST) that results in reduced count of current branches and, consequently, of power consumption. The proposed FDDA has the simplest CMOS structure presented in the literature so far. Furthermore, while the voltage supply is 0.5 V and the power consumption is 246.6 nW the circuit enjoys rail to rail input common mode range (ICMR) high common mode rejection ratio (CMRR) of 100.3 dB DC, power supply rejection ratio (PSRR) of 127.8 dB@ DC, voltage gain of 61.4 dB and gain bandwidth product of 6.98 kHz for 30 pF capacitive load. The total harmonic distortion (THD) is less than 0.08% for 500 mV/1 kHz input sine wave signal. The circuit was designed and simulated in Cadence/Spectre environment using 0.18 um CMOS process from TSMC.", "author_names": [ "Fabian Khateb", "Tomasz Kulej", "Montree Kumngern", "Costas Psychalinos" ], "corpus_id": 146112270, "doc_id": "146112270", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A compact power efficient 0.5 V fully differential difference amplifier", "venue": "AEU International Journal of Electronics and Communications", "year": 2019 }, { "abstract": "A programmable gain amplifier (PGA) is presented, targeting amplifying input signal with high dynamic range and low noise. The proposed PGA adopts fully balanced differential difference amplifier (FBDDA) as main amplifier. A class AB implementation of output stage is advantageous in order to achieve high current driving capability with very low quiescent power consumption. Combining resistor feedback loop controlled by digital signal, the proposed PGA achieves a dB linear gain range from 0 to 15dB with a gain step of 1dB. Compared with previous works, the theoretical analysis and measurement results prove that the proposed structure has lower noise. The circuit was designed and fabricated in SMIC 0.18m 3.3V process, showing a gain error of less than 0.25dB, a third harmonic distortion (HD3) of better than 83dB and a thermal noise of 1.6 nv/Hz. The measurement results indicate that the PGA described here has a 3dB bandwidth of 387.5MHz at maximum gain of 15dB. The PGA occupies a chip area of 0.1mm2.", "author_names": [ "Jingyu Wang", "Zhangming Zhu", "Shubin Liu", "Ruixue Ding" ], "corpus_id": 27495269, "doc_id": "27495269", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "A low noise programmable gain amplifier with fully balanced differential difference amplifier and class AB output stage", "venue": "Microelectron. J.", "year": 2017 }, { "abstract": "Abstract A new current mode Wheatstone bridge (CMWB) using a new fully differential operational transresistance amplifier (FDOTRA) is presented in this paper. This proposed FDOTRA is an active element for the proposed CMWB and has the advantages of low input and output impedances, input voltage calibration, high transimpedance (Rm) large input range, and wide bandwidth. The proposed CMWB uses only one active component FDOTRA and four resistors without degrading CMWB performance. The proposed CMWB has a simple structure, high precision, wide range, small volume, and low cost. Therefore, the advantages of the proposed CMWB are twofold. Firstly, it reduces the number of sensing passive and active elements. Secondly, the proposed CMWB circuit offers a significant improvement in accuracy compared to other CMWB integrated circuit (IC) The proposed CMWB has been analyzed, simulated, and implemented. The proposed FDOTRA has been fabricated with TSMC 0.35 mm 2P4M CMOS processes. Its supply voltages are 1.65 V. The open loop gain and 3 dB bandwidth of the proposed FDOTRA are 69.2 dB and 16 MHz, respectively. The open loop gain and 3 dB bandwidth of the FDOTRA based CMWB are 24.6 dB and 16 MHz, respectively. The experimental results show that the precision of the FDOTRA based CMWB is 92.4%", "author_names": [ "Yitsen Ku", "Yuh-Shyan Hwang", "Jiann-Jong Chen", "Chun-Chi Shih", "D Cheng" ], "corpus_id": 116054857, "doc_id": "116054857", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A new current mode wheatstone bridge based on a new fully differential operational transresistance amplifier", "venue": "AEU International Journal of Electronics and Communications", "year": 2019 }, { "abstract": "This paper presents a high CMRR and wideband current feedback Instrumentation Amplifier (IA) The proposed IA architecture consists of Fully Balanced Differential Difference Amplifier (FBDDA) and Differential Difference Amplifier (DDA) based on 2 generation current conveyor (CCII) with a buffer. From the simulation results evaluated by HSPICE, the proposed IA exhibits average CMRR was 109.3 dB higher than the conventional one. Furthermore, the proposed IA has higher closed loop gain over a larger bandwidth than corresponding voltage feedback.", "author_names": [ "Shota Mago", "Hiroki Tamura", "Koichi Tanno" ], "corpus_id": 8570091, "doc_id": "8570091", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "High CMRR and Wideband Current Feedback Instrumentation Amplifier Using Current Conveyors", "venue": "", "year": 2017 }, { "abstract": "A micropower high gain, low noise differential difference amplifier (DDA) is presented in this paper. The new circuit incorporates the gate bulk driven transistor pairs for input stage transconductance enhancement; the very high gain folded telescopic cascode structure that permits small headroom operation; and the replica tracking bias that sustains the circuit performance against variations of process, supply voltage and temperature. The DDA is designed using Global Foundries 1.8V/3.3V CMOS 0.18um process and simulated using the BSIM3 models. The simulated results for the DDA shows DC gain of 131.4dB and unity gain bandwidth of 1.097 MHz at a load of 30pF//200kO while consuming quiescent current of 10.7uA at a single 1.8V supply. The proposed DDA gives noise reduction of 15.56% with respect to that of the gate driven counterpart. It gives a noise efficiency factor (NEF) [1] of 6.7 when realizing a bio potential sensing circuit. The low noise, very high gain, floating inputs, low power and robust features of the proposed DDA are suitable for front end interface circuit in sensory systems.", "author_names": [ "Geok Teng Ong", "Pak Kwong Chan" ], "corpus_id": 25808359, "doc_id": "25808359", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "A micropower gate bulk driven differential difference amplifier with folded telescopic cascode topology for sensor applications", "venue": "2010 53rd IEEE International Midwest Symposium on Circuits and Systems", "year": 2010 }, { "abstract": "An improved operational transconductance amplifier (OTA) is presented in this work. The fully differential OTA adopts the current recycling technique and complementary NMOS and PMOS input branches to enhance the total transconductance. Moreover, in order to achieve higher current efficiency, a data driven biasing circuit was developed to dynamically adjust the power consumption of the amplifier. Two comparators were added to detect the voltage difference at the input nodes, and when the differential input is large enough to activate either comparator, extra biasing current is activated and poured into the amplifier to enhance its slew rate and gain bandwidth product (GBW) The threshold voltage of the complementary recycling folded cascode (CRFC) based comparator is configured to suppress overshoot. Complementary common mode feedback (CMFB) topology with local CMFB structure is built to acquire high common mode gain. The OTA was fabricated in SMIC 0.18 m m CMOS technology. The experimental result based on a capacitive feedback loop shows that the data driven operation improves the average slew rate of the amplifier from 10.2 V/ m s to 55.5 V/ m s while the power only increases by 150% The OTA has good potential to satisfy the fast settling demands for capacitive sensing circuits.", "author_names": [ "Xiantao Li", "Bo Hou", "Chunge Ju", "Qi Wei", "Bin Zhou", "Rong Zhang" ], "corpus_id": 213208468, "doc_id": "213208468", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Complementary Recycling Operational Transconductance Amplifier with Data Driven Enhancement of Transconductance", "venue": "", "year": 2019 }, { "abstract": "A new modified CMOS buffer amplifier with rail to rail input and output range is proposed by TSMC 0.35mm 2P4M process at 3.3V supply. The technique adds dummy pairs to sense the common mode range of the input differential pair and adjusts the output current accordingly. The amplifier provides high gain for a wider range of output voltages. Design considerations for reducing the impact of the additional circuitry on the core are provided. The technique described can be adapted for use with traditional fully differential rail to rail amplifiers, which performs 86.9dB ~92dB dc gain, 15 MHz unit gain bandwidth, high driving ability with high slew rate under a 100pF capacitance and a 3kO series resistance loading. The simulation results indicate that the settling times of rising and falling edge are within 3.5ms. It is effective for a high resolution and high speed LCD driver.", "author_names": [ "Shih-Han Lin", "Shu-Jung Chen", "Chih-Hsiung Shen" ], "corpus_id": 110728052, "doc_id": "110728052", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A New Architecture of LCD Driver of Rail to Rail Buffer with High Gain Wide Range", "venue": "", "year": 2010 }, { "abstract": "In this article, we propose a novel high performance complementary metal oxide semiconductor (CMOS) current differencing transconductance amplifier (CDTA) with a transconductance gain (GM) that can be linearly tuned by a voltage. By using a high speed, low voltage, cascaded current mirror active resistance compensation technique, the proposed CDTA circuit exhibits wide frequency bandwidths, high current tracking precisions as well as large output impedances. The linear tunable GM of the CDTA is designed with the use of linear composite metal oxide semiconductor field effect transistor as basic cells in the circuit. Combining these two approaches, several design concerns are studied, including: impedance characteristic, tracking errors, offset and linearity and noise. The prototype chip with a 0.25 mm2 area is fabricated in a GlobalFoundries'0.18 mm CMOS process. The simulated results and measured results with 0.8 V DC supply voltages are presented, and show extremely wide bandwidths and wide linear tuning range. In addition, a fully differential band pass filter for a high speed system is also given as an example to confirm the high performance of the proposed circuit.", "author_names": [ "Zanming Xia", "Chunhua Wang", "Jun Kuang", "Jie Jin" ], "corpus_id": 108708121, "doc_id": "108708121", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "A novel 0.8 V high performance voltage tunable CDTA with enhanced bandwidth", "venue": "", "year": 2016 }, { "abstract": "In this paper we present an optoelectronic architecture based on a current mode photodiode bridge readout circuit that performs differential measurements of the energy variations of nanosecond laser pulses. This operation is achieved by differentially detecting the currents photogenerated by two Si photodiodes one of which is used as the reference signal and the other measures the signal coming from variations of the laser pulse energy. The circuit has been designed for high speed operations (i.e. large bandwidth) and its features can be simply optimised as a function of the laser pulse width (e.g. in the nanosecond and subnanosecond regime) and of its repetition rate from few Hz up to few MHz. Moreover, the electronic circuitry allows to achieve the initial photodiode bridge balancing condition by variable control voltages so zeroing the overall interface offsets due to optical and electronic device mismatches and initial bridge unbalance conditions. The readout circuit has been fully characterised by performing both electrical and optical measurements and by varying its gain, detection sensitivity and energy per pulse changes between the signal and the reference employing 10ns laser pulses at a repetition rate of 20Hz. These measurements have been compared with those ones obtained using a standard commercial lock in amplifier as the conditioning circuit under the same experimental conditions. The proposed optoelectronic architecture is able to reach a maximum detection sensitivity of 7m V/ fJ corresponding to a detection resolution of the laser pulse energy variations equal to 0.14x10 3 fJ. These results prove an increase of 1225 in the detection sensitivity and resolution obtained by employing a lock in amplifier in a differential measurement configuration.", "author_names": [ "Andrea De Marcellis", "Elia Palange", "Simona Leone", "Guido Di Patrizio Stanchieri", "Marco Faccio" ], "corpus_id": 56170741, "doc_id": "56170741", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photodiode Bridge Based Differential Readout Circuit for High Sensitivity Measurements of Energy Variations of Laser Pulses for Optoelectronic Sensing Systems", "venue": "2018 New Generation of CAS (NGCAS)", "year": 2018 } ]

[ { "abstract": "We perform a comprehensive first principles study of the electronic properties of phosphorene nanoribbons, phosphorus nanotubes, multilayer phosphorene sheets, and heterobilayers of phosphorene and two dimensional (2D) transition metal dichalcogenide (TMDC) monolayer. The tensile strain and electric field effects on electronic properties of low dimensional phosphorene nanostructures are also investigated. Our calculations show that the bare zigzag phosphorene nanoribbons (z PNRs) are metals regardless of the ribbon width, whereas the bare armchair phosphorene nanoribbons (a PNRs) are semiconductors with indirect bandgaps and the bandgaps decrease with increasing ribbon width. We find that compressive (or tensile) strains can reduce (or enlarge) the bandgap of the bare a PNRs while an in plane electric field can significantly reduce the bandgap of the bare a PNRs, leading to the semiconductor to metal transition beyond certain electric field. For edge passivated PNR by hydrogen, z PNRs become semiconductor.", "author_names": [ "Hongyan Guo", "Ning Lu", "Jun Dai", "Xiaojun Wu", "Xiao Cheng Zeng" ], "corpus_id": 93011592, "doc_id": "93011592", "n_citations": 436, "n_key_citations": 7, "score": 1, "title": "Phosphorene Nanoribbons, Phosphorus Nanotubes, and van der Waals Multilayers", "venue": "", "year": 2014 }, { "abstract": "The structural and electronic properties of few layers of blue phosphorus and their van der Waals heterostructures with graphene were investigated by means of first principles electronic structure calculations. We study the four energetically most stable stacking configurations for multilayers of blue phosphorus. For all of them, the indirect band gap semiconductor character, are preserved. We show that the properties of monolayer graphene and single layer (bilayer) blue phosphorus are preserved in the van der Waals heterostructures. Further, our results reveal that under a perpendicular applied electric field, the position of the band structure of blue phosphorus with respect to that of graphene is tunable, enabling the effective control of the Schottky barrier height. Indeed, for the bilayer blue phosphorene on top of graphene, it is possible to even move the system into an Ohmic contact and induce a doping level of the blue phosphorene. All of these features are fundamental for the design of new nanodevices based on van der Waals heterostructures.", "author_names": [ "Renato Borges Pontes", "Roberto H Miwa", "Antonio J R da Silva", "Adalberto Fazzio", "Jose Eduardo Padilha" ], "corpus_id": 126225335, "doc_id": "126225335", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Layer dependent band alignment of few layers of blue phosphorus and their van der Waals heterostructures with graphene", "venue": "", "year": 2018 }, { "abstract": "Controlled syntheses in nanoscale structures should be expected and phosphorous nanotubes with predefined chiralities are important in electronic devices with tunable bandgap. Here, incorporating molecular dynamics simulations with theoretical analyses, we show that a zigzag phosphorene nanoribbon can self assemble and form a corresponding chiral phosphorous nanotube surrounding a template armchair phosphorous nanotube. The van der Waals potential between the nanoribbon and the nanotube is transformed to the intrinsic deformed and chemical bonding energies of the synthesized tube together with partial kinetic energy. The self assembly process has an apparent temperature dependence and size effect and the formed chiral tube is thermodynamically stable. Also, the chirality and measurement can be tuned by the radius of template tube and the aspect ratio of raw ribbon. The study suggests a novel and feasible approach for controlled synthesis of phosphorous nanotubes and thus is of great interest for semiconductor device applications.", "author_names": [ "Douxing Pan", "Tzuchiang Wang", "Chao Wang", "Wei Guo", "Yugui Yao" ], "corpus_id": 100269076, "doc_id": "100269076", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Self assembled chiral phosphorus nanotubes from phosphorene: a molecular dynamics study", "venue": "", "year": 2016 }, { "abstract": "Structural evolution induced and driven by a dual system and simultaneous passivation of phosphorene are reported. Different nano objects of phosphorene or black phosphorus (BP) are obtained using a new method of exfoliation, in which solvent and an ionic polymer are combined to weaken the van der Waals forces and to scissor the nanosheets. Nanoribbons, nanorods, and nanoneedles are obtained under mechanical force and ambient conditions. Ionic polymer chains assist in curling the monolayer or few layer nanosheet. Nafion is chosen to exfoliate the bulk BP and induce a morphological transition in BP nanosheets. The exfoliation of BP nanosheets results into thin and specific structures such as nanosheets/rods/needles. The nanosheets of phosphorene are covered and passivated simultaneously by the polymeric sheath that protects the nanosheets from degradation or oxidation and can be integrated with a device directly without any further coating.", "author_names": [ "Avneesh Kumar" ], "corpus_id": 213593460, "doc_id": "213593460", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Controlled nanostructures and simultaneous passivation of black phosphorus (phosphorene) with Nafion", "venue": "", "year": 2020 }, { "abstract": "Controlled synthesis is always expected in nanoscale structures and phosphorous nanotubes with predefined chiralities are very important to electronic devices with tunable bandgap. Here, we demonstrate by molecular dynamics simulations incorporating theoretical analysis that a zigzag phosphorene nanoribbon can be assembled spontaneously to form a corresponding chiral phosphorous nanotube on the outer side of an armchair phosphorous nanotube. The van der Waals potential between the nanoribbon and the nanotube is transformed to the intrinsic deformed and chemical bonding energy of the synthesized tube together with partial kinetic energy. The self assembly process has an apparent temperature dependence and size effect, and the formed chiral tube is stable thermodynamically and its chirality and measurement can be tuned by the radius of template tube and the length width ratio of raw ribbon. Extensive study shows that the chiral tube can be assembled by a phosphorene ribbon outside the phosphorous tube with isomeric chirality, but not with isomorphic chirality, performing a significant anisotropy; moreover, phosphorene ribbon inside phosphorous tube can not be either assembled into chiral tube, performing a significant location relevance.", "author_names": [ "Douxing Pan", "Tzuchiang Wang", "Yugui Yao", "Chao Wang" ], "corpus_id": 123521452, "doc_id": "123521452", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Self assembled chiral phosphorus nanotubes from phosphorene: a dynamic molecular study", "venue": "", "year": 2016 }, { "abstract": "Controlled syntheses in nanoscale structures is expected and phosphorous nanotubes with predefined chiralities are important in electronic devices with tunable bandgap. Herein, by incorporating molecular dynamics simulations and theoretical analyses, we predict that a zigzag phosphorene nanoribbon can self assemble and form a corresponding chiral phosphorous nanotube surrounding a template armchair phosphorous nanotube. The van der Waals potential between the nanoribbon and the nanotube is transformed to the intrinsic deformed and chemical bonding energies of the synthesized tube together with partial kinetic energy. In addition, we show that the self assembly process has an apparent temperature dependence and size effect. The formed chiral tube is thermodynamically stable and its chirality and measurement can be tuned by the radius of the template tube and the aspect ratio of the raw ribbon. Extensive studies demonstrate that the chiral tube can be self assembled by a phosphorene ribbon outside the template phosphorous tube with isomeric chirality, but neither with isomorphic chirality outside, nor inside, indicating significant anisotropy and location relevancy. Our studies suggest a novel and feasible approach for controlled synthesis of phosphorous nanotubes and thus of great interests for semiconductor device applications of two dimensional materials.", "author_names": [ "Douxing Pan", "Tzuchiang Wang", "Chao Wang", "Wei Guo", "Yugui Yao" ], "corpus_id": 126234193, "doc_id": "126234193", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Self assembled chiral phosphorus nanotubes from phosphorene predicted by molecular dynamics simulations", "venue": "", "year": 2016 }, { "abstract": "Edge induced gap states in finite phosphorene layers are examined using analytical models and density functional theory. The nature of such gap states depends on the direction of the cut. Armchair nanoribbons are insulating, whereas nanoribbons cut in the perpendicular direction (with zigzag and cliff type edges) are metallic, unless they undergo a reconstruction or distortion with cell doubling, which opens a gap. All stable nanoribbons with unsaturated edges have gap states that can be removed by hydrogen passivation. Armchair nanoribbon edge states decay exponentially with the distance to the edge and can be described by a nearly free electron model. Black phosphorus is a van der Waals bonded layered material, and the most stable form of of this element. Its peculiar orthorhombic structure resembling corrugated cardboard sets it apart from other two dimensional materials such as graphene and MoS2. Unlike those, it is highly anisotropic with respect to the directions in plane, [1 4] and therefore it offers new terrain to the exploration of physical phenomena in two dimensional materials. The isolation of the monolayer form, named phosphorene, has been recently achieved by mechanical cleavage followed by plasma thinning [5] and multi layered material is now routinely produced by exfoliation. [6, 7] Both have been theoretically predicted to be direct gap or nearly direct gap semiconductors with energy gaps ranging from 2 eV to 0.8 eV. [8] However, the bandstructure is far from typical. The effective masses for carriers are at least one order of magnitude higher along the direction of the to the zigzag ridges (y) than along the perpendicular direction (x) And the electron and hole masses are nearly the same along x, but very asymmetric along y. Further, due to the weak interaction between second and third nearest neighbors, it can easily be deformed under uniaxial compression, becoming, in sequence, an indirect gap semiconductor, a semimetal, a metal, and ultimately undergoing a transition to a square lattice. [1, 2, 9] Phosphorene can, in principle, be cut and tailored into derived nanostructures [10 12] An interesting feature of finite systems is the possibility of edge states. These states are localized at the system vacuum interface and decay exponentially away from it. The nature of the edge states depends not only on the crystal structure of the system, but also on the way it terminates. Understanding the physics of nanoribbon edges is fundamental for predicting the behavior of real finite systems and for designing more complex nanostructures, such as nanotubes and voids. In this paper, we analyze the electronic states induced by finite edges. We show that armchair edges, cut along the x direction, invariably lead to localized edge states, decaying exponentially towards the bulk. In contrast, edges cut along the y direction were found to introduce less localized states for nanoribbons. All the nanoribons are semiconducting in the large width limit. We first discuss the origin of these localized gap states. In our previous work [1] we have shown that tight binding has a limited utility for black phosphorus. Therefore, we will perform our analysis here using the nearly free electron model (NFEM) Before proceeding with the particular phosphorene case, we provide a derivation of the edge states for the reader's convenience following a standard procedure. We consider edge states in the gap of the infinite monolayer. Since these states are exponentially decaying, they must have an imaginary momentum component perpendicular to the edge. Assuming that the system is located in the negative half plane, the wavefunction inside it is p 1 ar X iv :1 40 4. 51 15 v3 co nd m at .m es h al l] 2 9 A ug 2 01 4 A. Carvalho1 A. S. Rodin1 A. H. Castro Neto1,2", "author_names": [ "Alexandra Carvalho", "Aleksandr Rodin", "Antonio H Castro Neto" ], "corpus_id": 119163259, "doc_id": "119163259", "n_citations": 106, "n_key_citations": 1, "score": 0, "title": "Phosphorene nanoribbons", "venue": "", "year": 2014 }, { "abstract": "Van der Waals interactions have a fundamental role in biology, physics and chemistry, in particular in the self assembly and the ensuing function of nanostructured materials. Here we utilize an efficient microscopic method to demonstrate that van der Waals interactions in nanomaterials act at distances greater than typically assumed, and can be characterized by different scaling laws depending on the dimensionality and size of the system. Specifically, we study the behaviour of van der Waals interactions in single layer and multilayer graphene, fullerenes of varying size, single wall carbon nanotubes and graphene nanoribbons. As a function of nanostructure size, the van der Waals coefficients follow unusual trends for all of the considered systems, and deviate significantly from the conventionally employed pairwise additive picture. We propose that the peculiar van der Waals interactions in nanostructured materials could be exploited to control their self assembly.", "author_names": [ "Vivekanand V Gobre", "Alexandre Tkatchenko" ], "corpus_id": 12365659, "doc_id": "12365659", "n_citations": 204, "n_key_citations": 4, "score": 0, "title": "Scaling laws for van der Waals interactions in nanostructured materials", "venue": "Nature communications", "year": 2013 }, { "abstract": "Based on first principles calculations, we have predicted an ultrathin metastable phosphorus nanotube as the smallest phosphorus nanotube and obtained a new class of two dimensional phosphorus allotropes via assembling the smallest phosphorus nanotubes into planar structures in different stacking orientations. These two dimensional phosphorene allotropes possess remarkable stabilities due to the strong inter tube van der Waals interactions, which cause an energy release of about 30 70 meV/atom depending on their stacking manners. Our results show that most of these two dimensional van der Waals phosphorene allotropes are energetically more favorable than the experimentally viable black alpha P and blue beta P. Three of them showing relatively higher probability to be synthesized in future are further confirmed to be dynamically stable semiconductors with strain tunable band gaps and remarkable piezoelectricity, which may have potential applications in nano sized sensors, piezotronics, and energy harvesting in portable electronic nano devices", "author_names": [ "Zhenqing Li", "Chaoyu He", "Tao Ouyang", "Chunxiao Zhang", "Caoxin Tang", "Rudolf A Romer", "Jianxin Zhong" ], "corpus_id": 19223660, "doc_id": "19223660", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "New allotropes of phosphorene with remarkable stability and intrinsic piezoelectricity", "venue": "", "year": 2017 }, { "abstract": "Molecular orbital theory predicts that interactions between lone pair electrons give rise to van der Waals forces between layers due to the nonequivalent hybridization in bulk black phosphorus. First principles calculations show that phosphorene nanoribbons (PNRs) have a high activity and can be bonded easily with oxygen atoms and hydroxyl groups, indicating that the PNRs can be oxidized easily. The cliff PNR configuration can be maintained when it is passivated with hydroxyl groups, indicating that it could be stable in a strong alkaline environment. Upon oxidation of their zigzag, armchair, and cliff edges, phosphorene nanoribbons can be changed from semimetallic to semiconducting, and the band gap can be changed from direct to indirect. OHO (OH O) and OH (O H) passivated PNRs have intrinsic spin magnetic moments of approximately 2.00 mB, which originate from the edge unsaturation electrons and the symmetry reduction. Therefore, oxidized PNRs might have potential applications in photoelectro.", "author_names": [ "Bangfu Ding", "Wei Chen", "Zilong Tang", "Junying Zhang" ], "corpus_id": 100871556, "doc_id": "100871556", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "Tuning Phosphorene Nanoribbon Electronic Structure through Edge Oxidization", "venue": "", "year": 2016 } ]

[ { "abstract": "Chemical vapor deposition (CVD) has proven its surpassing advantages, such as larger scale, interlayer orientation control, and clean interface, in the synthesis of transitional metal dichalcogenide (TMDC) semiconductor/semiconductor van der Waals (vdW) heterostructures. However, it is suffering problems of high melting points and low chemical reactivity of metal oxide feedstocks in the preparation of high quality metal/semiconductor (M/S) TMDC vdW heterostructures. Here, for the first time, we report the synthesis of the M/S TMDC vdW heterostructure NbS2/MoS2 via a one step halide assisted CVD method, which effectively overcomes the drawbacks of metal oxide precursors. This one step method provides the high quality and clean interface of the NbS2/MoS2 heterostructure, which has been proved by the transmission electron microscopy characterization. A mechanism that MoS2 finishes the growth first and subsequently serves as a superior substrate for the growth of NbS2 is proposed. This novel method will open", "author_names": [ "Qundong Fu", "Xiaowei Wang", "Jiadong Zhou", "Juan Juan Xia", "Qingsheng Zeng", "Danhui Lv", "Chao Zhu", "Xiaolei Wang", "Yue Shen", "Xiaomin Li", "Younan Hua", "Fucai Liu", "Zexiang Shen", "Chuanhong Jin", "Zheng Liu" ], "corpus_id": 104268927, "doc_id": "104268927", "n_citations": 35, "n_key_citations": 0, "score": 1, "title": "One Step Synthesis of Metal/Semiconductor Heterostructure NbS2/MoS2", "venue": "", "year": 2018 }, { "abstract": "Two dimensional materials are an emerging class of new materials with a wide range of electrical properties and potential practical applications. Although graphene is the most well studied two dimensional material, single layers of other materials, such as insulating BN (ref. 2) and semiconducting MoS2 (refs 3, 4) or WSe2 (refs 5, 6) are gaining increasing attention as promising gate insulators and channel materials for field effect transistors. Because monolayer MoS2 is a direct bandgap semiconductor due to quantum mechanical confinement, it could be suitable for applications in optoelectronic devices where the direct bandgap would allow a high absorption coefficient and efficient electron hole pair generation under photoexcitation. Here, we demonstrate ultrasensitive monolayer MoS2 phototransistors with improved device mobility and ON current. Our devices show a maximum external photoresponsivity of 880 A W( 1) at a wavelength of 561 nm and a photoresponse in the 400 680 nm range. With recent developments in large scale production techniques such as liquid scale exfoliation and chemical vapour deposition like growth, MoS2 shows important potential for applications in MoS2 based integrated optoelectronic circuits, light sensing, biomedical imaging, video recording and spectroscopy.", "author_names": [ "Oriol Lopez-Sanchez", "Dominik S Lembke", "M Kayci", "Aleksandra Radenovic", "Andras Kis" ], "corpus_id": 5435971, "doc_id": "5435971", "n_citations": 3092, "n_key_citations": 33, "score": 0, "title": "Ultrasensitive photodetectors based on monolayer MoS2.", "venue": "Nature nanotechnology", "year": 2013 }, { "abstract": "Two dimensional materials are attractive for use in next generation nanoelectronic devices because, compared to one dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two dimensional material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS(2) have a large intrinsic bandgap of 1.8 eV (ref. 16) previously reported mobilities in the 0.5 3 cm(2) V( 1) s( 1) range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room temperature single layer MoS(2) mobility of at least 200 cm(2) V( 1) s( 1) similar to that of graphene nanoribbons, and demonstrate transistors with room temperature current on/off ratios of 1 x 10(8) and ultralow standby power dissipation. Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS(2) could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.", "author_names": [ "Branimir Radisavljevic", "Aleksandra Radenovic", "Jacopo Brivio", "Valentina Giacometti", "Andras Kis" ], "corpus_id": 205446552, "doc_id": "205446552", "n_citations": 9689, "n_key_citations": 117, "score": 0, "title": "Single layer MoS2 transistors.", "venue": "Nature nanotechnology", "year": 2011 }, { "abstract": "Large area MoS(2) atomic layers are synthesized on SiO(2) substrates by chemical vapor deposition using MoO(3) and S powders as the reactants. Optical, microscopic and electrical measurements suggest that the synthetic process leads to the growth of MoS(2) monolayer. The TEM images verify that the synthesized MoS(2) sheets are highly crystalline.", "author_names": [ "Yi-Hsien Lee", "Xin-Quan Zhang", "Wenjing Zhang", "M T Chang", "Cheng-Te Lin", "Kai Chang", "Ya-Chu Yu", "Jacob Tse-Wei Wang", "Chia-Seng Chang", "Lain-Jong Li", "Tsung-Wu Lin" ], "corpus_id": 11713759, "doc_id": "11713759", "n_citations": 2501, "n_key_citations": 41, "score": 0, "title": "Synthesis of large area MoS2 atomic layers with chemical vapor deposition.", "venue": "Advanced materials", "year": 2012 }, { "abstract": "A new phototransistor based on the mechanically exfoliated single layer MoS(2) nanosheet is fabricated, and its light induced electric properties are investigated in detail. Photocurrent generated from the phototransistor is solely determined by the illuminated optical power at a constant drain or gate voltage. The switching behavior of photocurrent generation and annihilation can be completely finished within ca. 50 ms, and it shows good stability. Especially, the single layer MoS(2) phototransistor exhibits a better photoresponsivity as compared with the graphene based device. The unique characteristics of incident light control, prompt photoswitching, and good photoresponsivity from the MoS(2) phototransistor pave an avenue to develop the single layer semiconducting materials for multifunctional optoelectronic device applications in the future.", "author_names": [ "Zongyou Yin", "Hai Li", "Hong Li", "Lin Jiang", "Yumeng Shi", "Yinghui Sun", "Gang Lu", "Qing Yu Zhang", "Xiaodong Chen", "Hua Zhang" ], "corpus_id": 27038582, "doc_id": "27038582", "n_citations": 2570, "n_key_citations": 16, "score": 0, "title": "Single layer MoS2 phototransistors.", "venue": "ACS nano", "year": 2012 }, { "abstract": "2D metal semiconductor heterostructures based on transition metal dichalcogenides (TMDs) are considered as intriguing building blocks for various fields, such as contact engineering and high frequency devices. Although, a series of p n junctions utilizing semiconducting TMDs have been constructed hitherto, the realization of such a scheme using 2D metallic analogs has not been reported. Here, the synthesis of uniform monolayer metallic NbS2 on sapphire substrate with domain size reaching to a millimeter scale via a facile chemical vapor deposition (CVD) route is demonstrated. More importantly, the epitaxial growth of NbS2 WS2 lateral metal semiconductor heterostructures via a \"two step\" CVD method is realized. Both the lateral and vertical NbS2 WS2 heterostructures are achieved here. Transmission electron microscopy studies reveal a clear chemical modulation with distinct interfaces. Raman and photoluminescence maps confirm the precisely controlled spatial modulation of the as grown NbS2 WS2 heterostructures. The existence of the NbS2 WS2 heterostructures is further manifested by electrical transport measurements. This work broadens the horizon of the in situ synthesis of TMD based heterostructures and enlightens the possibility of applications based on 2D metal semiconductor heterostructures.", "author_names": [ "Yu Zhang", "Lei Yin", "Junwei Chu", "Tofik Ahmed Shifa", "Jing Xia", "Feng Wang", "Yao Wen", "Xueying Zhan", "Zhenxing Wang", "Jun He" ], "corpus_id": 52068663, "doc_id": "52068663", "n_citations": 51, "n_key_citations": 0, "score": 0, "title": "Edge Epitaxial Growth of 2D NbS2 WS2 Lateral Metal Semiconductor Heterostructures.", "venue": "Advanced materials", "year": 2018 }, { "abstract": "Layer by layer stacking or lateral interfacing of atomic monolayers has opened up unprecedented opportunities to engineer two dimensional heteromaterials. Fabrication of such artificial heterostructures with atomically clean and sharp interfaces, however, is challenging. Here, we report a one step growth strategy for the creation of high quality vertically stacked as well as in plane interconnected heterostructures of WS2/MoS2 via control of the growth temperature. Vertically stacked bilayers with WS2 epitaxially grown on top of the MoS2 monolayer are formed with preferred stacking order at high temperature. A strong interlayer excitonic transition is observed due to the type II band alignment and to the clean interface of these bilayers. Vapour growth at low temperature, on the other hand, leads to lateral epitaxy of WS2 on MoS2 edges, creating seamless and atomically sharp in plane heterostructures that generate strong localized photoluminescence enhancement and intrinsic p n junctions. The fabrication of heterostructures from monolayers, using simple and scalable growth, paves the way for the creation of unprecedented two dimensional materials with exciting properties.", "author_names": [ "Yongji Gong", "Junhao Lin", "Xingli Wang", "Gang Shi", "Sidong Lei", "Zhong Lin", "Xiaolong Zou", "Gonglan Ye", "Robert Vajtai", "Boris I Yakobson", "Humberto Terrones", "Mauricio Terrones", "Bengkang Tay", "Jun Lou", "Sokrates T Pantelides", "Zheng Liu", "Wu Zhou", "Pulickel M Ajayan" ], "corpus_id": 205410476, "doc_id": "205410476", "n_citations": 1421, "n_key_citations": 13, "score": 0, "title": "Vertical and in plane heterostructures from WS2/MoS2 monolayers.", "venue": "Nature materials", "year": 2014 }, { "abstract": "Electronic and spintronic devices rely on the fact that free charge carriers in solids carry electric charge and spin. There are, however, other properties of charge carriers that might be exploited in new families of devices. In particular, if there are two or more minima in the conduction band (or maxima in the valence band) in momentum space, and if it is possible to confine charge carriers in one of these valleys, then it should be possible to make a valleytronic device. Valley polarization, as the selective population of one valley is designated, has been demonstrated using strain and magnetic fields, but neither of these approaches allows dynamic control. Here, we demonstrate that optical pumping with circularly polarized light can achieve complete dynamic valley polarization in monolayer MoS(2) (refs 11, 12) a two dimensional non centrosymmetric crystal with direct energy gaps at two valleys. Moreover, this polarization is retained for longer than 1 ns. Our results, and similar results by Zeng et al. demonstrate the viability of optical valley control and suggest the possibility of valley based electronic and optoelectronic applications in MoS(2) monolayers.", "author_names": [ "Kin Fai Mak", "Keliang He", "Jie Shan", "Tony F Heinz" ], "corpus_id": 23248686, "doc_id": "23248686", "n_citations": 2498, "n_key_citations": 23, "score": 0, "title": "Control of valley polarization in monolayer MoS2 by optical helicity.", "venue": "Nature nanotechnology", "year": 2012 }, { "abstract": "Transition metal dichalcogenides (TMDs) have attracted considerable interest for exploration of next generation electronics and optoelectronics in recent years. Fabrication of in plane lateral heterostructures between TMDs has opened up excellent opportunities for engineering two dimensional materials. The creation of high quality heterostructures with a facile method is highly desirable but it still remains challenging. In this work, we demonstrate a one step growth method for the construction of high quality MoS2 WS2 in plane heterostructures. The synthesis was carried out using ambient pressure chemical vapor deposition (APCVD) with the assistance of sodium chloride (NaCl) It was found that the addition of NaCl played a key role in lowering the growth temperatures, in which the Na containing precursors could be formed and condensed on the substrates to reduce the energy of the reaction. As a result, the growth regimes of MoS2 and WS2 are better matched, leading to the formation of in plane heterostructures in a single step. The heterostructures were proved to be of high quality with a sharp and clear interface. This newly developed strategy with the assistance of NaCl is promising for synthesizing other TMDs and their heterostructures.", "author_names": [ "Zhan Wang", "Yong Xie", "Haolin Wang", "Ruixue Wu", "Tang Nan", "Yongjie Zhan", "Jing Sun", "Teng Jiang", "Ying Zhao", "Yimin Lei", "Mei Yang", "Weidong Wang", "Qing Zhu", "Xiao-hua Ma", "Yue Hao" ], "corpus_id": 9434927, "doc_id": "9434927", "n_citations": 53, "n_key_citations": 1, "score": 0, "title": "NaCl assisted one step growth of MoS2 WS2 in plane heterostructures.", "venue": "Nanotechnology", "year": 2017 }, { "abstract": "Research on graphene and other two dimensional atomic crystals is intense and is likely to remain one of the leading topics in condensed matter physics and materials science for many years. Looking beyond this field, isolated atomic planes can also be reassembled into designer heterostructures made layer by layer in a precisely chosen sequence. The first, already remarkably complex, such heterostructures (often referred to as 'van der Waals' have recently been fabricated and investigated, revealing unusual properties and new phenomena. Here we review this emerging research area and identify possible future directions. With steady improvement in fabrication techniques and using graphene's springboard, van der Waals heterostructures should develop into a large field of their own.", "author_names": [ "Andre K Geim", "Irina Vladimirovna Grigorieva" ], "corpus_id": 205234832, "doc_id": "205234832", "n_citations": 5193, "n_key_citations": 13, "score": 0, "title": "Van der Waals heterostructures", "venue": "Nature", "year": 2013 } ]

[ { "abstract": "A novel ferroelectric semiconductor junction (FSJ) based two terminal memristor is demonstrated as a synaptic device for the first time. In this novel FSJ device, a metal ferroelectric semiconductor (FS) metal crossbar structure is used, instead of a metal ferroelectric insulator metal structure for a conventional ferroelectric tunnel junction (FTJ) so that an ultra thin ferroelectric insulator is not required. Meanwhile, the FSJ also offers energy efficiency advantage over the conventional filament based resistive random access memory (RRAM) device because the conductance of the FSJ scales with the junction area. Experimentally, a ferroelectric semiconductor a In2Se3 based crossbar FSJ (c FSJ) as a synaptic device is demonstrated. Ferroelectric resistive switching is clearly observed in both planar FSJ (p FSJ) by in plane polarization switching and c FSJ by out of plane polarization switching. Conductance potentiation and depression in the c FSJ are measured and benchmarked at both original size and projected to 32 nm node with different synaptic devices. a In2Se3 c FSJ shows good on line learning accuracy ~92 low latency and energy consumption due to the short write pulse width and large RON.", "author_names": [ "Mengwei Si", "Peide D Ye", "Y Luo", "Wonil Chung", "Hagyoul Bae", "Dongqi Zheng", "Jinjun Li", "Jingkai Qin", "Gang Qiu", "S Yu" ], "corpus_id": 209442949, "doc_id": "209442949", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "A Novel Scalable Energy Efficient Synaptic Device: Crossbar Ferroelectric Semiconductor Junction", "venue": "2019 IEEE International Electron Devices Meeting (IEDM)", "year": 2019 }, { "abstract": "We report on world's smallest HfO2 based Resistive RAM (RRAM) cell to date, featuring a novel Hf/HfOx resistive element stack, with an area of less than 10x10 nm2, fast ns range on/off switching times at low voltages and with a switching energy per bit of #60;0.1pJ. With excellent endurance of more than 5.107cycles, large on/off verified window >50) no closure of the on/off window after 30hrs/200C and failure free device operation after 30hrs/250C thermal stress, the major device level nonvolatile memory requirements are met. Furthermore, we clarify the impact of film crystallinity on cell operation from a scalability viewpoint, the role of the cap layer and bring insight into the switching mechanisms.", "author_names": [ "Bogdan Govoreanu", "G S Kar", "Y -Y Chen", "V Paraschiv", "S Kubicek", "Andrea Fantini", "Iuliana P Radu", "Ludovic Goux", "Sergiu Clima", "Robin Degraeve", "Nico Jossart", "Olivier Richard", "T Vandeweyer", "Kang Kuk Seo", "Paul Hendrickx", "Geoffrey Pourtois", "Hugo Bender", "Laith Altimime", "Dirk J Wouters", "Jorge A Kittl", "Malgorzata Jurczak" ], "corpus_id": 20372833, "doc_id": "20372833", "n_citations": 567, "n_key_citations": 32, "score": 0, "title": "10x10nm2 Hf/HfOx crossbar resistive RAM with excellent performance, reliability and low energy operation", "venue": "2011 International Electron Devices Meeting", "year": 2011 }, { "abstract": "A memristor is a two terminal electronic device whose conductance can be precisely modulated by charge or flux through it. Here we experimentally demonstrate a nanoscale silicon based memristor device and show that a hybrid system composed of complementary metal oxide semiconductor neurons and memristor synapses can support important synaptic functions such as spike timing dependent plasticity. Using memristors as synapses in neuromorphic circuits can potentially offer both high connectivity and high density required for efficient computing.", "author_names": [ "Sung-Hyun Jo", "Ting Chang", "Idongesit E Ebong", "Bhavitavya Bhadviya", "Pinaki Mazumder", "Wei Yang Lu" ], "corpus_id": 15097859, "doc_id": "15097859", "n_citations": 2785, "n_key_citations": 86, "score": 0, "title": "Nanoscale memristor device as synapse in neuromorphic systems.", "venue": "Nano letters", "year": 2010 }, { "abstract": "We demonstrate large scale (1 kb) high density crossbar arrays using a Si based memristive system. A two terminal hysteretic resistive switch (memristive device) is formed at each crosspoint of the array and can be addressed with high yield and ON/OFF ratio. The crossbar array can be implemented as either a resistive random access memory (RRAM) or a write once type memory depending on the device configuration. The demonstration of large scale crossbar arrays with excellent reproducibility and reliability also facilitates further studies on hybrid nano/CMOS systems.", "author_names": [ "Sung-Hyun Jo", "Kuk-Hwan Kim", "Wei Lu" ], "corpus_id": 16515301, "doc_id": "16515301", "n_citations": 499, "n_key_citations": 8, "score": 0, "title": "High density crossbar arrays based on a Si memristive system.", "venue": "Nano letters", "year": 2009 }, { "abstract": "In this paper, the recent progress of synaptic electronics is reviewed. The basics of biological synaptic plasticity and learning are described. The material properties and electrical switching characteristics of a variety of synaptic devices are discussed, with a focus on the use of synaptic devices for neuromorphic or brain inspired computing. Performance metrics desirable for large scale implementations of synaptic devices are illustrated. A review of recent work on targeted computing applications with synaptic devices is presented.", "author_names": [ "Duygu Kuzum", "Shimeng Yu", "H -S Philip Wong" ], "corpus_id": 44782140, "doc_id": "44782140", "n_citations": 719, "n_key_citations": 11, "score": 0, "title": "Synaptic electronics: materials, devices and applications.", "venue": "Nanotechnology", "year": 2013 }, { "abstract": "In this paper, we consider devices, circuits, and systems comprised of transistors with integrated ferroelectrics. Said structures are actively being considered by various semiconductor manufacturers as they can address a large and unique design space. Transistors with integrated ferroelectrics could (i) enable a better switch (i.e. offer steeper subthreshold swings) (ii) are CMOS compatible, (iii) have multiple operating modes (i.e. I V characteristics can also enable compact, 1 transistor, non volatile storage elements, as well as analog synaptic behavior) and (iv) have been experimentally demonstrated (i.e. with respect to all of the aforementioned operating modes) These device level characteristics offer unique opportunities at the circuit, architectural, and system level, and are considered here from device, circuit/architecture, and foundry level perspectives.", "author_names": [ "Ahmedullah Aziz", "Evelyn T Breyer", "An Chen", "Xiaoming Chen", "Suman Datta", "Sumeet Kumar Gupta", "Michael Hoffmann", "Xiaobo Sharon Hu", "Adrian M Ionescu", "Matthew Jerry", "Thomas Mikolajick", "Halid Mulaosmanovic", "Kai Ni", "Michael Thaddeus Niemier", "Ian O'Connor", "Atanu K Saha", "Stefan Slesazeck", "Sandeep Krishna Thirumala", "Xunzhao Yin" ], "corpus_id": 5058501, "doc_id": "5058501", "n_citations": 41, "n_key_citations": 1, "score": 0, "title": "Computing with ferroelectric FETs: Devices, models, systems, and applications", "venue": "2018 Design, Automation Test in Europe Conference Exhibition (DATE)", "year": 2018 }, { "abstract": "Various new nonvolatile memory (NVM) technologies have emerged recently. Among all the investigated new NVM candidate technologies, spin torque transfer memory (STT RAM, or MRAM) phase change random access memory (PCRAM) and resistive random access memory (ReRAM) are regarded as the most promising candidates. As the ultimate goal of this NVM research is to deploy them into multiple levels in the memory hierarchy, it is necessary to explore the wide NVM design space and find the proper implementation at different memory hierarchy levels from highly latency optimized caches to highly density optimized secondary storage. While abundant tools are available as SRAM/DRAM design assistants, similar tools for NVM designs are currently missing. Thus, in this paper, we develop NVSim, a circuit level model for NVM performance, energy, and area estimation, which supports various NVM technologies, including STT RAM, PCRAM, ReRAM, and legacy NAND Flash. NVSim is successfully validated against industrial NVM prototypes, and it is expected to help boost architecture level NVM related studies.", "author_names": [ "Xiangyu Dong", "Cong Xu", "Yuan Xie", "Norman P Jouppi" ], "corpus_id": 1096997, "doc_id": "1096997", "n_citations": 873, "n_key_citations": 162, "score": 0, "title": "NVSim: A Circuit Level Performance, Energy, and Area Model for Emerging Nonvolatile Memory", "venue": "IEEE Transactions on Computer Aided Design of Integrated Circuits and Systems", "year": 2012 }, { "abstract": "Recent advances in neuroscience together with nanoscale electronic device technology have resulted in huge interests in realizing brain like computing hardwares using emerging nanoscale memory devices as synaptic elements. Although there has been experimental work that demonstrated the operation of nanoscale synaptic element at the single device level, network level studies have been limited to simulations. In this work, we demonstrate, using experiments, array level associative learning using phase change synaptic devices connected in a grid like configuration similar to the organization of the biological brain. Implementing Hebbian learning with phase change memory cells, the synaptic grid was able to store presented patterns and recall missing patterns in an associative brain like fashion. We found that the system is robust to device variations, and large variations in cell resistance states can be accommodated by increasing the number of training epochs. We illustrated the tradeoff between variation tolerance of the network and the overall energy consumption, and found that energy consumption is decreased significantly for lower variation tolerance.", "author_names": [ "Sukru Burc Eryilmaz", "Duygu Kuzum", "Rakesh Gnana David Jeyasingh", "Sangbum Kim", "Matthew J BrightSky", "Chung Hon Lam", "H -S Philip Wong" ], "corpus_id": 5364487, "doc_id": "5364487", "n_citations": 149, "n_key_citations": 1, "score": 0, "title": "Brain like associative learning using a nanoscale non volatile phase change synaptic device array", "venue": "Front. Neurosci.", "year": 2014 }, { "abstract": "Memristive devices are electrical resistance switches that can retain a state of internal resistance based on the history of applied voltage and current. These devices can store and process information, and offer several key performance characteristics that exceed conventional integrated circuit technology. An important class of memristive devices are two terminal resistance switches based on ionic motion, which are built from a simple conductor/insulator/conductor thin film stack. These devices were originally conceived in the late 1960s and recent progress has led to fast, low energy, high endurance devices that can be scaled down to less than 10 nm and stacked in three dimensions. However, the underlying device mechanisms remain unclear, which is a significant barrier to their widespread application. Here, we review recent progress in the development and understanding of memristive devices. We also examine the performance requirements for computing with memristive devices and detail how the outstanding challenges could be met.", "author_names": [ "Jianhua Joshua Yang", "Dmitri B Strukov", "Duncan R Stewart" ], "corpus_id": 38314993, "doc_id": "38314993", "n_citations": 2324, "n_key_citations": 50, "score": 0, "title": "Memristive devices for computing.", "venue": "Nature nanotechnology", "year": 2013 }, { "abstract": "Learn the basic properties and designs of modern VLSI devices, as well as the factors affecting performance, with this thoroughly updated second edition. The first edition has been widely adopted as a standard textbook in microelectronics in many major US universities and worldwide. The internationally renowned authors highlight the intricate interdependencies and subtle tradeoffs between various practically important device parameters, and also provide an in depth discussion of device scaling and scaling limits of CMOS and bipolar devices. Equations and parameters provided are checked continuously against the reality of silicon data, making the book equally useful in practical transistor design and in the classroom. Every chapter has been updated to include the latest developments, such as MOSFET scale length theory, high field transport model, and SiGe base bipolar devices.", "author_names": [ "Yuan Taur", "Tak H Ning" ], "corpus_id": 109378086, "doc_id": "109378086", "n_citations": 2283, "n_key_citations": 237, "score": 0, "title": "Fundamentals of Modern VLSI Devices", "venue": "", "year": 1998 } ]

[ { "abstract": "Semiconductor hybrid pixel detectors of X ray radiation are recently commonly used in many fields, such as material science, medicine, and synchrotron measurements. One of the most common problems to be solved in the pixel detector design are offsets and gain spreads in the readout electronics, which come from very small sizes of the transistors used. The mentioned problem can be mitigated by implementing a \"digital assisted analog\" design approach, where the offsets are corrected by trimming digital to analog converters (DACs) fed with proper digital data. To find the correct input value for each DAC, the execution of the calibrating procedure is necessary, which is usually run using assistive devices, such as PCs or FPGAs, and is a time consuming task. This paper presents the concept of the pixel matrix detector on chip calibration, that enables standalone improvement of the device accuracy. The proposed solution integrates the RISC V based microprocessor, Pixel Matrix Controller, and pixel matrix detector inside the single integrated circuit. The solution does not require data transfer out of the chip and is therefore significantly faster than off chip methods.", "author_names": [ "Pawel Skrzypiec", "Robert Szczygiel" ], "corpus_id": 233465571, "doc_id": "233465571", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Development of On Chip Calibration for Hybrid Pixel Detectors", "venue": "2021 24th International Symposium on Design and Diagnostics of Electronic Circuits Systems (DDECS)", "year": 2021 }, { "abstract": "An upgrade of the ATLAS experiment for the High Luminosity phase of LHC is planned for 2024 and foresees the replacement of the present Inner Detector (ID) with a new Inner Tracker (ITk) completely made of silicon devices. Depleted active pixel sensors built with the High Voltage CMOS (HV CMOS) technology are investigated as an option to cover large areas in the outermost layers of the pixel detector and are especially interesting for the development of monolithic devices which will reduce the production costs and the material budget with respect to the present hybrid assemblies. For this purpose the H35DEMO, a large area HV CMOS demonstrator chip, was designed by KIT, IFAE and University of Liverpool, and produced in AMS 350 nm CMOS technology. It consists of four pixel matrices and additional test structures. Two of the matrices include amplifiers and discriminator stages and are thus designed to be operated as monolithic detectors. In these devices the signal is mainly produced by charge drift in a small depleted volume obtained by applying a bias voltage of the order of 100V. Moreover, to enhance the radiation hardness of the chip, this technology allows to enclose the electronics in the same deep N WELLs which are also used as collecting electrodes. In this contribution the characterisation of H35DEMO chips and results of the very first beam test measurements of the monolithic CMOS matrices with high energetic pions at CERN SPS will be presented.", "author_names": [ "S Terzo", "E Cavallaro", "Raimon Casanova", "Francesco Armando di Bello", "Fabian Forster", "Sebastian Grinstein", "Ivan Per'ic", "Carles Puigdengoles", "Branislav Ristic", "M Vicente Barreto Pinto", "Ev Energies", "", "D'epartement de Physique Nucl'eaire et Corpusculaire", "University of Geneva", "Instituci'o Catalana de Recerca i Estudis Avanccats", "Karlsruher Institut fur Technologie", "University of Liverpool", "United Kingdom" ], "corpus_id": 109930779, "doc_id": "109930779", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Characterisation of novel prototypes of monolithic HV CMOS pixel detectors for high energy physics experiments", "venue": "", "year": 2017 }, { "abstract": "JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two dimensional hybrid pixel detector under development for photon science applications at free electron laser and synchrotron facilities. In particular, JUNGFRAU detectors will equip the Aramis end stations of SwissFEL, an X ray free electron laser currently under construction at the Paul Scherrer Institut in Villigen, Switzerland. JUNGFRAU has been designed specifically to meet the challenges of photon science at XFELs, including high frame rates, single photon sensitivity in combination with a high dynamic range, vacuum compatibility and tilable modules. This has resulted in a charge integrating detector with three dynamically adjusting gains, a low noise of 55 ENC RMS, readout speeds in excess of 2 kHz, single photon sensitivity down to 2 keV (with a signal to noise ratio of 10) and a dynamic range covering four orders of magnitude at 12 keV. Each JUNGFRAU module consists of eight chips of 256 x 256 pixels, each 75 x 75 mm2 in size. The chips are arranged in 2 x 4 formation and bump bonded to a single silicon sensor 320 mm thick, resulting in an active area of approximately 4 x 8 cm2 per module. Multi module vacuum compatible systems comprising up to 16 Mpixels (32 modules) will be used at SwissFEL. The design of SwissFEL and the JUNGFRAU system for the Aramis end station A will be introduced, together with results from early prototypes and a characterisation using the first batch of final JUNGFRAU modules. Plans and first results of the pixel by pixel calibration will also be shown. The vacuum compatibility of the JUNGFRAU module is demonstrated for the first time.", "author_names": [ "Sophie Redford", "Anna Bergamaschi", "Martin Bruckner", "Sebastian Cartier", "Roberto Dinapoli", "Yasin Ekinci", "Erik Frojdh", "Dominic Greiffenberg", "Davit Mayilyan", "Davide Mezza", "Aldo Mozzanica", "Rajendran Rajeev", "Marco Ramilli", "Christian Ruder", "L Schadler", "Bernd Schmitt", "Xintian Shi", "Dhanya Thattil", "Gemma Tinti", "Jiangdong Zhang" ], "corpus_id": 125104247, "doc_id": "125104247", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Calibration status and plans for the charge integrating JUNGFRAU pixel detector for SwissFEL", "venue": "", "year": 2016 }, { "abstract": "The next steps in particle physics will involve colliders that are able to investigate the TeV energy scale so that many of the unanswered questions can be addressed. The Compact Linear Collider (CLIC) aims to do this through collisions of electrons and positrons at a high luminosity and at centre of mass energies of up to 3 TeV. In addition to the accelerator, a detector system is under development that targets precision physics measurements in an environment with a high rate of beam induced backgrounds. One of the sub detectors that faces particularly challenging requirements is the pixel vertex detector. To achieve its goals, hybrid readout chips either bump bonded to planar sensors or capacitively coupled to High Voltage CMOS (HV CMOS) sensors, fabricated in a commercial 180 nm technology, are under study. Both of these sensor options have a small pitch of 25 x 25 um2 and are hybridised to 65 nm CLICpix readout ASICs. Initial investigations have shown the feasibility of such technologies, but further, and more detailed studies are needed. This is done through a series of simulations and measurements to assess the suitability of each technology for the CLIC vertex detector. Simulations of the custom designed CCPDv3 HV CMOS sensor have been carried out using the Sentaurus Technology Computer Aided Design (TCAD) simulation software. Firstly, a comparison of a 2D model and a resource intensive 3D model was carried out, showing an agreement within 15% of the sensor properties, such as electric field, depletion depth and charge collection. However, there is a difference of 40% for the capacitance, indicating 3D simulations are better suited to capacitance measurements. The 2D model was then expanded to include a multi pixel model for studies of charge sharing. Lab characterisations of planar sensor assemblies were undertaken to determine the quality of the bump bonds and define regions with an acceptable level of working pixels for three assemblies. Calibrations were performed to convert the Time over Threshold (ToT) energy measurements and Digital to Analogue (DAC) threshold voltage steps into physical units. For the HV CMOS assemblies, the analogue output of several pixels was compared to the ToT response of the CLICpix readout chip so that the simulation results could be converted to ToT and compared to the beam test data. The performance of the HV CMOS assemblies was assessed at the CERN SPS using 120 GeV/c secondary beams. This was done over an incident angle range of 0 80deg and showed excellent efficiency above 99.7% and a spatial resolution of 5 7 um after eta correction was applied to correct for non linear charge sharing. The measurements were then compared to the simulations, showing a good agreement for the current voltage, breakdown and charge collection properties. The validated simulations were used to investigate possible prospects for improved performance that can be applied in future sensor designs. Two avenues of investigation were explored: increasing the bulk resistivity and biasing from the backside. The largest improvement was for a back bias model with a resistivity of 1 kOcm.", "author_names": [ "Matthew Daniel Buckland" ], "corpus_id": 126431331, "doc_id": "126431331", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Simulation and evaluation of HV CMOS pixel sensors for the CLIC vertex detector", "venue": "", "year": 2018 }, { "abstract": "ePix10K is a hybrid pixel detector developed at SLAC for demanding free electron laser (FEL) applications, providing an ultrahigh dynamic range (245 eV to 88 MeV) through gain auto ranging. It has three gain modes (high, medium and low) and two auto ranging modes (high to low and medium to low) The first ePix10K cameras are built around modules consisting of a sensor flip chip bonded to 4 ASICs, resulting in 352x384 pixels of 100 \\mu$m x 100 \\mu$m each. We present results from extensive testing of three ePix10K cameras with FEL beams at LCLS, resulting in a measured noise floor of 245 eV rms, or 67 e$ equivalent noise charge (ENC) and a range of 11000 photons at 8 keV. We demonstrate the linearity of the response in various gain combinations: fixed high, fixed medium, fixed low, auto ranging high to low, and auto ranging medium to low, while maintaining a low noise (well within the counting statistics) a very low cross talk, perfect saturation response at fluxes up to 900 times the maximum range, and acquisition rates of up to 480 Hz. Finally, we present examples of high dynamic range x ray imaging spanning more than 4 orders of magnitude dynamic range (from a single photon to 11000 photons/pixel/pulse at 8 keV) Achieving this high performance with only one auto ranging switch leads to relatively simple calibration and reconstruction procedures. The low noise levels allow usage with long integration times at non FEL sources. ePix10K cameras leverage the advantages of hybrid pixel detectors with high production yield and good availability, minimize development complexity through sharing the hardware, software and DAQ development with all other versions of ePix cameras, while providing an upgrade path to 5 kHz, 25 kHz and 100 kHz in three steps over the next few years, matching the LCLS II requirements.", "author_names": [ "G Blaj", "Angelo Dragone", "Christopher J Kenney", "Faisal T Abu-Nimeh", "Pietro Caragiulo", "Dionisio Doering", "Maciej Kwiatkowski", "Jack Pines", "Matt Weaver", "Sebastien Boutet", "Gabriella Carini", "C -E Chang", "Philip Hart", "Jasmine Hasi", "Matt J Hayes", "Ryan Herbst", "Jason E Koglin", "Kazutaka Nakahara", "Julie D Segal", "Gunther Haller" ], "corpus_id": 119426663, "doc_id": "119426663", "n_citations": 9, "n_key_citations": 1, "score": 0, "title": "Performance of ePix10K, a high dynamic range, gain auto ranging pixel detector for FELs.", "venue": "", "year": 2019 }, { "abstract": "New developments in medical imaging head towards semiconductor detectors flip chip bonded to CMOS readout chips. In this work, detectors fabricated on SI GaAs bulk material were bonded to Photon Counting Chips. 1 This PCC consists of a matrix of 64 64 identical square pixels (170mm 170mm) with a 15 bit counter in each cell. We investigated the imaging properties of these detector systems under exposure of a dental X ray tube. First, a dose calibration of the X ray tube was performed. Fixed pattern noise in flood exposure images was determined for a fixed dose and an image correction method, which uses a gain map, was applied. For characterising the imaging properties, the signal to noise ratio (SNR) was calculated as function of exposure dose. Finally, the dynamic range of the system was estimated. 2001 Elsevier Science B.V. All rights reserved.", "author_names": [ "C Schwarz", "Michael Campbell", "R Goeppert", "J Ludwig", "Bettina Mikulec", "M Rogalla", "Keith Runge", "A Soeldner-Rembold", "K M Smith", "W Snoeys", "J Watt" ], "corpus_id": 122074753, "doc_id": "122074753", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Dose dependent X ray measurements using a 64x64 hybrid GaAs pixel detector with photon counting", "venue": "", "year": 2001 }, { "abstract": "The LHCb experiment requires positive kaon identification in the momentum range 2 100 GeV/c. This is provided by two ring imaging Cherenkov detectors. The stringent requirements on the photon detectors are fully satisfied by the novel pixel hybrid photon detector, HPD. The HPD is a vacuum tube with a quartz window, S20 photo cathode, cross focusing electron optics and a silicon anode encapsulated within the tube. The anode is a 32/spl times/256 pixels hybrid detector, with a silicon sensor bump bonded onto a readout chip containing 8192 channels with analogue front end and digital read out circuitry. An external magnetic field influences the trajectory of the photoelectrons and could thereby degrade the inherent excellent space resolution of the HPD. The HPDs must be operational in the fringe magnetic field of the LHCb magnet. This paper reports on an extensive experimental characterization of the distortion effects. The characterization has allowed the development of parameterisations and of a compensation algorithm. A calibration procedure based on the imaging of pre defined test patterns that has been developed for the RICH detectors is also proposed.", "author_names": [ "Gianluca Aglieri Rinella", "T F Bellunalo", "Carmelo D'Ambrosio", "Roger W Forty", "Thierry Gys", "M Patel", "Didier Piedigrossi", "A Van Lysebetten" ], "corpus_id": 10191126, "doc_id": "10191126", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Pixel hybrid photon detector magnetic distortions characterization and compensation", "venue": "IEEE Symposium Conference Record Nuclear Science 2004.", "year": 2004 }, { "abstract": "The Silicon Pixel Detector (SPD) is the innermost detector of the ALICE Inner Tracking System and the closest one to the interaction point. In order to operate the detector in a safe way, a control system was developed in the framework of PVSS which allows to monitor and control a large number of parameters such as temperatures, currents, voltages, etc. The control system of the SPD implements interlock features to protect the detector against overheating and prevents operating it in case of malfunctions. The nearly 50,000 parameters required to fully configure the detector are stored in a database which employs automatic configuration versions after a new calibration run has been carried out. Several user interface panels were developed to allow experts and non expert shifters to operate the detector in an easy and safe way. This contribution provides an overview of the SPD control system. I. THE SILICON PIXEL DETECTOR SPD is based on a hybrid silicon pixels technology and contains around 9.8 M read out channels. It is composed of 120 half staves (HS) mounted on 10 carbon fibre supporting sectors (Fig. 1) Each half stave is made of two ladders, a Multi Chip Module (MCM) and an aluminium polyimide multilayer bus. Each ladder consists of 5 front end chips flipchip bonded to a 200 microns thick silicon sensor [1] Figure 1: The Silicon Pixel Detector The MCM constitutes the on detector electronics and performs operations such as clock distributions, data multiplexing, etc. The multilayer bus provides the connection between the MCM and the front end chips, while communication between the MCM and the off detector electronics (Routers) is assured by three single mode optical fiber links. The SPD low voltage power supply (PS) system is based on 20 CAEN A3009 dc dc converter modules (1 for each half sector) housed in 4 CAEN Easy3000 crates located about 40m from the detector. The sensor bias voltage is provided by 10 CAEN A1519 modules (1 for each sector) housed in a CAEN SY1527 mainframe 100 m away from the detector. II. OVERVIEW OF THE DETECTOR CONTROL SYSTEM The DCS plays a leading role in operating the SPD and fulfils very stringent requirements. The ALICE Detector Control System (DCS) as well as all the LHC experiments, is supervised by a SCADA system (Supervisory Control and Data Acquisition) based on a software platform called PVSSII [2] The aim of every control system is to supervise all the operations carried out in its structure and to react promptly in case of misbehaviors. The ALICE DCS group, in collaboration with every detector, foresaw a series of constrains to integrate the control system of each sub detector into a unique control system. The DCS of the SPD was designed according to such requirements. Standard components were mainly used to reduce maintenance efforts and, in few cases, dedicated components were developed for specific and innovative tasks. The block diagram shows the connections between the hardware and software components (Fig. 2) Figure 2: Detector control system scheme There are 4 sub control systems: PS control, Interlock control, Cooling Control and the Front End driver (FED) control. The first three directly communicate with the hardware via Ethernet (TCP/IP, OPC protocol) while the last one uses the same protocol to connect to the FED, which is the driver that communicates with the off detector electronics (20 routers) via a VME bus.", "author_names": [ "Claudio Bortolin", "Romualdo Santoro", "Ivan Amos Cali", "C Torcato de Matos" ], "corpus_id": 62327860, "doc_id": "62327860", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Development and commissioning of the ALICE pixel detector control system", "venue": "", "year": 2009 }, { "abstract": "ECLAIRs is a 2 D coded mask imaging telescope on board the Sino French SVOM space mission, in order to detect and locate precisely Gamma ray bursts (GRBs) in the 4 150 keV energy range. Its design has been drawn by the central objective of achieving a low energy threshold of 4 keV. In that respect, the camera is formed by 6400 Schottky CdTe detectors organized on elementary hybrid matrices of 4 x 8 pixels, which will be polarized up to 450V and operated at 20degC. The remarkable low energy threshold homogeneity required for the detection plane has been achieved thanks to an extensive characterization of the innovative hybrid module composed of 32 CdTe detectors, associated to a very lownoise 32 channel ASIC chip, and both assembled on specific ceramics. In this paper, we outline the SVOM space mission, and then describe the ECLAIRs instrument. We continue by focusing on the different elements of the camera prototype named \"ProtoDPIX\" Indeed, this is a very important step for the project because it is the first time we are working in Camera Mode with 800 detectors. Then, we present some spectral results obtained from this, to show its great spectroscopic performance, after explaining the setup. Thus, we performed a large spectral measurements campaign at the regulated temperature of 20degC, using several calibrated radioactive sources (241Am and 57Co) Moreover, we will resume the future steps of development of the final flight model camera and the different constraints due to the short planning and the very challenging technical requirements. In conclusion, thanks to this prototype we are in the process of validating a complete detection chain, from the detectors to the backend electronics, and from mechanical study through thermal design. Finally, we are checking the performance to be ready for integration, functional tests and calibration stages.", "author_names": [ "Carine Amoros", "Baptiste Houret", "Karine Lacombe", "V Waegebaert", "J L Atteia", "Armelle Bajat", "L Bautista", "I Belkacem", "S Bordon", "Bertrand Cordier", "M Galliano", "Olivier Godet", "Francois Gonzalez", "Philippe Guillemot", "Stephan Maestre", "Pierre Mandrou", "W Marty", "Roger Pons", "Damien Rambaud", "Pascale Ramon" ], "corpus_id": 115844817, "doc_id": "115844817", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Status of technological development on ECLAIRs camera onboard the SVOM space mission", "venue": "Astronomical Telescopes Instrumentation", "year": 2018 }, { "abstract": "A Golden Era for Astronomy: The Advent of CCDS and Infrared Arrays. A Golden Era for Astronomy: The Advent of CCDS and Infrared Arrays. Detector Manufacturers. Overview of Astronomy Arrays at Raytheon Infrared Operations (RIO) A New Photon Counting Detector: Intensified CMOS APS. Preliminary Test Measurements of the SPAD Array. Preliminary Characterization of Two High Speed, Back Illuminated CCD Image Sensors. Broadband (200 1000 NM) Back Illuminated CCD Imagers. Orion: A 1 5 Micron Focal Plane for the 21st Century. Performance of 5 Micron, Molecular Beam Epitaxy HgCdTe Sensor Chip Assemblies (SCAs) for the NGST Mission and Ground Based Astronomy. Cosmic Rays and Other Nonsense in Astronomical CCD Imagers. An Overview of CCD Development at Lawrence Berkeley National Laboratory. Scientific CMOS Pixels. Secrets of E2V Technologies CCDs. Progress in Ultra Low Noise Hybrid and Monolithic FPAs for Visible and Infrared. A Marconi CCD42 40 with Anti Blooming. Very Large Format Back Illuminated CCDS. Compound Semiconductor Detectors. Optical Photon Counting STJ Activities at ESA. Silicon on Insulator Based Single Chip Image Sensors. Large Format and Scientific Detectors at Fairchild Imaging. HgCdTe Detectors for the Hubble Space Telescope Wide Field Camera 3 IR Channel. CMOS Active Pixel Sensor Developments at the Rutherford Appleton Laboratory. Observatory Status/Plans. Eso's Optical Detector Sytems in the VLT Operations Era. The Detector Systems of the Keck Observatory: UV to 25 Microns. IR Detector Developments at Eso. Controller Developments. Detector Work at the UKATC. CCD Camera Systems for the GTC. Detectors at CTIO: Present Status and Future Plans. Strange Happenings in the Dungeons. NOAO Observatory Plans. MONSOON Image Acquisition System. Instrumentation. Improved CCD Detectors for High Speed, Charge Exchange Spectroscopy Studies on the DIII D Tokamak. A CCD Wavefront Sensing System for the ESO Multi Conjugate Adaptive Optics Demonstrator (MAD) CFHT's Skyprobe: True Atmospheric Attenuation Measurement in the Telescope Field. CFHT's Flyeyes: Assessing On sky Performance of the New MIT/LL CCID 35 CCD Curvature Wavefront Sensor. Ultra Clean CCD Cryostats. The Impact of Astronomy Technologies on Chemical Analysis. A CCD based Curvature Wavefront Sensor for Adaptive Optics in Astronomy. Performance and Results of the NAOS Visible Wavefront Sensor. Fabry Perot Observations Using a New GaAs Photon Counting System. Near IR Fringe Tracking for VLTI: the FINITO Detection System. OSIRIS Detectors. The Optimized Cryostat for the LBC Camera. The Omegacam Shutter. Ultra Deep Optical Spectroscopy with PMAS. The Tololo all Sky Camera. The Orthogonal Parallel Imaging Transfer Camera. Giga Pixels and Sky Surveys. The Hubble Space Telescope Wide Field Camera 3 Instrument Charge Coupled Device Detectors. Camera and Detector Development in the Space Science and Technology Department of the Rutherford Appleton Laboratory. Compact CCD Camera. Electronics. The Design and Testing of a Cryogenic Pre amplifier for the Rockwell HAWAII and HAWAII II Detector Arrays. The New Generation CCD Controller: First Results. ISPI Software. Compact CCD Guider Camera for Magelian. Readout Techniques for Drift and Low Frequency Noise Rejection in Infrared Arrays. AzCam: A Windows Based CCD/CMOS Client/Server Data Acquisition System. Upgrade of Eso's Fiera CCD Controller and Pulpo Subsystem. An Optimized Data Acquisition System Without Reset Anomaly for the Hawaii and Hawaii 2 Arrays. GTC Acquisition Cameras and Wavefront Sensors. A New CCD Controller at UCO/Lich Observatory. The use of ASIC Thecnology in the Development of Compact, Low Power CCD Cameras. Detector Testing and Characterization. Characterization of the Si: As Blocked Impurity Band (BIB) Detector in Keck's Long Wavelength Spectrometer (LWS) Characterizing the CCDS of the Omegacam Wide Angle Camera. Emir HAWAII 2 Detector Test Bench. Emir HAWAII II First Test Results. Test Results with 2Kx2K MCT Arrays. The HAWAII 2 2048x2048 HgCdTe Detector Arrays. How Accurate Are QE Measurements? Focal Plane Mosaics. The Electronic Controller of the 40 CCDS MegaCam Mosaic. Design of the CRIRES 512x4096 Pixel Aladdin InSB Focal Plane Array Detector Mosaic. Performance of HAWAII 2 FPA for Subaru Multi Object Near Infrared Camera and Spectrograph. Wide Field Focal Plane Arrays for UKIRT and VISTA. Fully Buttable Imagers. Mosaic Focal Plane Development. Space Missions. In flight Performance of the Advanced Camera for Surveys CCDS. On the Implementation and Calibration of the Focal Plane for GAIA. Behaviour of a Raytheon IRFPA (438x5 Micron Focal Plane for the 21st Century. Performance of 5 Micron, Molecular Beam Epitaxy HgCdTe Sensor Chip Assemblies (SCAs) for the NGST Mission and Ground Based Astronomy. Cosmic Rays and Other Nonsense in Astronomical CCD Imagers. An Overview of CCD Development at Lawrence Berkeley National Laboratory. Scientific CMOS Pixels. Secrets of E2V Technologies CCDs. Progress in Ultra Low Noise Hybrid and Monolithic FPAs for Visible and Infrared. A Marconi CCD42 40 with Anti Blooming. Very Large Format Back Illuminated CCDS. Compound Semiconductor Detectors. Optical Photon Counting STJ Activities at ESA. Silicon on Insulator Based Single Chip Image Sensors. Large Format and Scientific Detectors at Fairchild Imaging. HgCdTe Detectors for the Hubble Space Telescope Wide Field Camera 3 IR Channel. CMOS Active Pixel Sensor Developments at the Rutherford Appleton Laboratory. Observatory Status/Plans. Eso's Optical Detector Sytems in the VLT Operations Era. The Detector Systems of the Keck Observatory: UV to 25 Microns. IR Detector Developments at Eso. Controller Developments. Detector Work at the UKATC. CCD Camera Systems for the GTC. Detectors at CTIO: Present Status and Future Plans. Strange Happenings in the Dungeons. NOAO Observatory Plans. MONSOON Image Acquisition System. Instrumentation. Improved CCD Detectors for High Speed, Charge Exchange Spectroscopy Studies on the DIII D Tokamak. A CCD Wavefront Sensing System for the ESO Multi Conjugate Adaptive Optics Demonstrator (MAD) CFHT's Skyprobe: True Atmospheric Attenuation Measurement in the Telescope Field. CFHT's Flyeyes: Assessing On sky Performance of the New MIT/LL CCID 35 CCD Curvature Wavefront Sensor. Ultra Clean CCD Cryostats. The Impact of Astronomy Technologies on Chemical Analysis. A CCD based Curvature Wavefront Sensor for Adaptive Optics in Astronomy. Performance and Results of the NAOS Visible Wavefront Sensor. Fabry Perot Observations Using a New GaAs Photon Counting System. Near IR Fringe Tracking for VLTI: the FINITO Detection System. OSIRIS Detectors. The Optimized Cryostat for the LBC Camera. The Omegacam Shutter. Ultra Deep Optical Spectroscopy with PMAS. The Tololo all Sky Camera. The Orthogonal Parallel Imaging Transfer Camera. Giga Pixels and Sky Surveys. The Hubble Space Telescope Wide Field Camera 3 Instrument Charge Coupled Device Detectors. Camera and Detector Development in the Space Science and Technology Department of the Rutherford Appleton Laboratory. Compact CCD Camera. Electronics. The Design and Testing of a Cryogenic Pre amplifier for the Rockwell HAWAII and HAWAII II Detector Arrays. The New Generation CCD Controller: First Results. ISPI Software. Compact CCD Guider Camera for Magelian. Readout Techniques for Drift and Low Frequency Noise Rejection in Infrared Arrays. AzCam: A Windows Based CCD/CMOS Client/Server Data Acquisition System. Upgrade of Eso's Fiera CCD Controller and Pulpo Subsystem. An Optimized Data Acquisition System Without Reset Anomaly for the Hawaii and Hawaii 2 Arrays. GTC Acquisition Cameras and Wavefront Sensors. A New CCD Controller at UCO/Lich Observatory. The use of ASIC Thecnology in the Development of Compact, Low Power CCD Cameras. Detector Testing and Characterization. Characterization of the Si: As Blocked Impurity Band (BIB) Detector in Keck's Long Wavelength Spectrometer (LWS) Characterizing the CCDS of the Omegacam Wide Angle Camera. Emir HAWAII 2 Detector Test Bench. Emir HAWAII II First Test Results. Test Results with 2Kx2K MCT Arrays. The HAWAII 2 2048x2048 HgCdTe Detector Arrays. How Accurate Are QE Measurements? Focal Plane Mosaics. The Electronic Controller of the 40 CCDS MegaCam Mosaic. Design of the CRIRES 512x4096 Pixel Aladdin InSB Focal Plane Array Detector Mosaic. Performance of HAWAII 2 FPA for Subaru Multi Object Near Infrared Camera and Spectrograph. Wide Field Focal Plane Arrays for UKIRT and VISTA. Fully Buttable Imagers. Mosaic Focal Plane Development. Space Missions. In flight Performance of the Advanced Camera for Surveys CCDS. On the Implementation and Calibration of the Focal Plane for GAIA. Behaviour of a Raytheon IRFPA (438x270) under High Energy Protons. Radiation Damage Effects in XMM Newton Epic Mos CCDs. 95 Million Pixel Focal Plane for Use on the Kepler Discovery Mission. Sub electon Noise Focal Plane Arrays. L3CCDs: Fast Photon Counting for Optical Interferometry. L3CCD's: Low Readout Noise CCDs in Astronomy. Zero Noise CCD. First Results of an L3CCD in Photon Counting Mode.", "author_names": [ "Paola Amico", "James William Beletic", "Jenna E Beletic" ], "corpus_id": 106816668, "doc_id": "106816668", "n_citations": 51, "n_key_citations": 5, "score": 0, "title": "Scientific detectors for astronomy the beginning of a new era", "venue": "", "year": 2004 } ]

[ { "abstract": "Enhancement mode metal oxide semiconductor field effect transistors (MOSFETs) with trench gate structures have been developed. These MOSFETs show excellent DC characteristics with on voltage of 5.1 V, i.e. enhancement mode operation and extremely high channel mobilities of 133 cm2/(V s) This structure enables us to realize vertical switching devices with high breakdown voltage and highly integrated low on resistance with the usage of excellent physical parameters of GaN. This excellent performance of these devices breaks though the realization of GaN based power switching transistors.", "author_names": [ "Hirotaka Otake", "Shin Egami", "Hiroaki Ohta", "Yasushi Nanishi", "Hidemi Takasu" ], "corpus_id": 110600970, "doc_id": "110600970", "n_citations": 63, "n_key_citations": 1, "score": 2, "title": "GaN Based Trench Gate Metal Oxide Semiconductor Field Effect Transistors with Over 100 cm2/(V s) Channel Mobility", "venue": "", "year": 2007 }, { "abstract": "Completely vertical trench gate metal oxide semiconductor field effect transistors (MOSFETs) have been produced using gallium nitride (GaN) for the first time. These MOSFETs exhibited enhancement mode operation with a threshold voltage of 3.7 V and an on resistance of 9.3 mOcm2. The channel mobility was estimated to be 131 cm2/(Vs) when all the resistances except for that of the channel are considered. Such structures, which satisfy the key words \"vertical\" \"trench gate\" and \"MOSFET\" will enable us to fabricate practical GaN based power switching devices.", "author_names": [ "Hirotaka Otake", "Kentaro Chikamatsu", "Atsushi Yamaguchi", "Tatsuya Fujishima", "Hiroaki Ohta" ], "corpus_id": 93821686, "doc_id": "93821686", "n_citations": 149, "n_key_citations": 2, "score": 0, "title": "Vertical GaN Based Trench Gate Metal Oxide Semiconductor Field Effect Transistors on GaN Bulk Substrates", "venue": "", "year": 2008 }, { "abstract": "We have demonstrated the enhancement mode n channel gallium nitride (GaN) metal oxide field effect transistors (MOSFETs) on homoepitaxial GaN substrates using the selective area regrowth and ion implantation techniques. Both types of MOSFETs perform normally off operations. The GaN MOSFETs fabricated using the regrowth method perform superior characteristics over the other relative devices fabricated using the ion implantation technique. The electron mobility of 100 cm2/V*s, subthreshold of 500 mV/dec, and transconductance of 14 ms/mm are measured in GaN MOSFETs based on the implantation technique. Meanwhile, the GaN MOSFETs fabricated using the regrowth method perform the electron mobility, transconductance, and subthreshold of 120 cm2/V s, 18 ms/mm, and 300 mV/dec, respectively. Additionally, the MOSFETs with the regrown p GaN gate body show the Ion/Ioff ratio of approximately 4 x 107, which is, to our knowledge, among the best results of GaN MOSFETs to date. This research contributes a valuable information for the design and fabrication of power switching devices based on GaN.", "author_names": [ "Huu Trung Nguyen", "Hisashi Yamada", "Toshikazu Yamada", "Tokio Takahashi", "Mitsuaki Shimizu" ], "corpus_id": 211246849, "doc_id": "211246849", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Fabrication and Evaluation of N Channel GaN Metal Oxide Semiconductor Field Effect Transistors Based on Regrown and Implantation Methods", "venue": "Materials", "year": 2020 }, { "abstract": "InGaSb on insulator (InGaSb OI) and InAs/InGaAs/InAs on insulator (InAs/InGaAs OI) structures have been realized on Si by a direct wafer bonding (DWB) technology using atomic layer deposition Al2O3. While strain introduced in InGaSb channel layers grown on InAs can enhance the hole mobility of the Sb based channel layers, a difficult issue of fabricating InGaSb OI wafers is to obtain a smooth InGaSb surface, which is mandatory for wafer bonding. In this study, the surface of a 20 nm thick In0.185Ga0.815Sb channel grown on an InAs (100) substrate and an InAs (2.5 nm)/In0.185Ga0.815Sb (20 nm)/InAs (2.5 nm) channel with a 20 nm thick GaSb buffer layer grown on an InAs (100) substrate by metal organic chemical vapor deposition have a root mean square of the surface roughness as low as 0.16 and 0.22 nm, respectively, over a scan area of 10 x 10 mm2, which are smooth enough to employ the wafer bonding. As a result, the fabrication of the InGaSb OI wafers by the DWB and the operation of InGaSb OI p channel metal oxide semiconductor field effect transistors (p MOSFETs) by using the DWB wafers are demonstrated. Also, the performance of InGaSb OI p MOSFETs is found to be improved by inserting ultrathin InAs layers between InGaSb and insulating buried oxide layers. An InGaSb OI and an InAs/InGaAs OI p MOSFET under the accumulation mode operation exhibit a peak mobility of ~161 and ~273 cm2/V s, respectively. The channel hole mobility of the InGaSb OI p MOSFET is higher than that of the GaSb on insulator (GaSb OI) p MOSFET and can exceed that of Si p MOSFETs.InGaSb on insulator (InGaSb OI) and InAs/InGaAs/InAs on insulator (InAs/InGaAs OI) structures have been realized on Si by a direct wafer bonding (DWB) technology using atomic layer deposition Al2O3. While strain introduced in InGaSb channel layers grown on InAs can enhance the hole mobility of the Sb based channel layers, a difficult issue of fabricating InGaSb OI wafers is to obtain a smooth InGaSb surface, which is mandatory for wafer bonding. In this study, the surface of a 20 nm thick In0.185Ga0.815Sb channel grown on an InAs (100) substrate and an InAs (2.5 nm)/In0.185Ga0.815Sb (20 nm)/InAs (2.5 nm) channel with a 20 nm thick GaSb buffer layer grown on an InAs (100) substrate by metal organic chemical vapor deposition have a root mean square of the surface roughness as low as 0.16 and 0.22 nm, respectively, over a scan area of 10 x 10 mm2, which are smooth enough to employ the wafer bonding. As a result, the fabrication of the InGaSb OI wafers by the DWB and the operation of InGaSb OI p channel metal.", "author_names": [ "Masafumi Yokoyama", "Haruki Yokoyama", "Mitsuru Takenaka", "Shinichi Takagi" ], "corpus_id": 126716240, "doc_id": "126716240", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "InGaSb on insulator p channel metal oxide semiconductor field effect transistors on Si fabricated by direct wafer bonding", "venue": "Journal of Applied Physics", "year": 2019 }, { "abstract": "GaN metal oxide semiconductor field effect transistors (MOSFETs) on AlGaN/GaN heterostructure with a recess gate were fabricated and characterized. The device showed good pinch off characteristics and a maximum field effect mobility of 145.2 cm2*V 1*s 1. The effects of etching gas of Cl2 and SiCl4 were investigated in the gate recess process. SiCl4 etched devices showed higher channel mobility and lower threshold voltage. Atomic force microscope measurement was done to investigate the etching profile with different etching protection mask. Compared with photoresist, SiO2 masked sample showed lower surface roughness and better profile with stepper sidewall and weaker trenching effect resulting in higher channel mobility in the MOSFET.", "author_names": [ "Qingpeng Wang", "Jin-Ping Ao", "Pangpang Wang", "Ying Jiang", "Liuan Li", "Kazuya Kawaharada", "Yang Liu" ], "corpus_id": 137537120, "doc_id": "137537120", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "GaN metal oxide semiconductor field effect transistors on AlGaN/GaN heterostructure with recessed gate", "venue": "Frontiers of Materials Science", "year": 2015 }, { "abstract": "We have evaluated specific on state resistance (R on,sp) and switching performance of various GaN power field effect transistors (FETs) with 600 and 1200 V ratings using analytical calculation and numerical simulation. The normally off GaN power FET family includes lateral p GaN gate high electron mobility transistors (HEMTs) lateral metal oxide semiconductor (MOS) channel HEMTs, current aperture vertical electron transistors (CAVETs) and vertical U shaped trench gate MOS field effect transistors (UMOSFETs) This study shows the advantages of vertical GaN power FETs over lateral GaN power HEMTs. These advantages include lower R on,sp and smaller switching energy loss, especially at higher blocking voltages (1200 V) At 600 V, lateral P GaN gate HEMTs are competitive with vertical power FETs. Vertical GaN CAVETs perform better than both lateral HEMTs and vertical UMOSFETs at both voltage ratings, benefiting from its lowest R on*Q G figure of merit.", "author_names": [ "Zhibo Guo", "Collin W Hitchcock", "T Paul Chow" ], "corpus_id": 182650518, "doc_id": "182650518", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Comparative performance evaluation of lateral and vertical GaN high voltage power field effect transistors", "venue": "Japanese Journal of Applied Physics", "year": 2019 }, { "abstract": "In this paper, the normally off N channel lateral 4H Si C metal oxide semiconductor field effect transistors(MOSFFETs) have been fabricated and characterized. A sandwich (nitridation oxidation nitridation) type process was used to grow the gate dielectric film to obtain high channel mobility. The interface properties of 4H Si C/SiO2 were examined by the measurement of HF I V, G V, and C V over a range of frequencies. The ideal C V curve with little hysteresis and the frequency dispersion were observed. As a result, the interface state density near the conduction band edge of 4H Si C was reduced to 2 x 1011 e V 1*cm 2, the breakdown field of the grown oxides was about 9.8 MV/cm, the median peak fieldeffect mobility is about 32.5 cm2*V 1*s 1, and the maximum peak field effect mobility of 38 cm2*V 1*s 1 was achieved in fabricated lateral 4H Si C MOSFFETs.", "author_names": [ "" ], "corpus_id": 113428386, "doc_id": "113428386", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fabrication and characterization of the normally,off N channel lateral 4H SiC metal oxide semiconductor field effect transistors", "venue": "", "year": 2016 }, { "abstract": "We report room temperature to 200 degC operation of n Al0.65Ga0.35N channel metal semiconductor field effect transistors (MESFET) grown over high quality AlN/sapphire templates. For this temperature range, the source drain currents, threshold voltages, and dc transconductance values remain nearly unchanged with an estimated field effect mobility of ~90 cm2/V s at 200 degC and currents of >100 mA/mm. The analysis of the temperature dependent current voltage characteristics of the gate source Schottky barrier diode reveals that the leakage currents arise from Frenkel Poole emission. The capacitance voltage data show no hysteresis, indicating a high quality Schottky barrier interface. These MESFET's have excellent potential for use as a high temperature power electronic or a solar blind ultraviolet sensing device.", "author_names": [ "Sakib Muhtadi", "Seongmo Hwang", "Antwon Coleman", "Fatima Asif", "Alexander V Lunev", "Mvs Chandrashekhar", "Asif Khan" ], "corpus_id": 125230526, "doc_id": "125230526", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "High temperature operation of n AlGaN channel metal semiconductor field effect transistors on low defect AlN templates", "venue": "", "year": 2017 }, { "abstract": "Performance improvement of InGaAs buried channel metal oxide semiconductor field effect transistors (MOSFETs) has been achieved by inserting InAs layer and properly designing the inserted layer position. In0.7Ga0.3As and InAs channel buried channel MOSFETs were fabricated and analyzed including drive current, transconductance, effective mobility, and subthreshold swing. All InAs buried channel devices show good off state and saturation property. By inserting InAs in the middle of InGaAs channel (InGaAs/InAs/InGaAs channel) 37% enhancement of high field effective channel mobility was achieved over devices with pure InGaAs channel. Devices with InAs inserted in the middle exhibits peak effective channel mobility around 6140 cm2/V s and subthreshold swing of 107 mV/dec.", "author_names": [ "Fei Xue", "Han Zhao", "Yen-Ting Chen", "Yanzhen Wang", "Fei Zhou", "Jack C Lee" ], "corpus_id": 109894617, "doc_id": "109894617", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "InAs inserted InGaAs buried channel metal oxide semiconductor field effect transistors with atomic layer deposited gate dielectric", "venue": "", "year": 2011 }, { "abstract": "We demonstrated the advantage of aluminum oxynitride (AlON) gate insulator in enhancing the performance of recessed gate AlGaN/GaN based metal oxide semiconductor heterojunction field effect transistors (MOS HFETs) fabricated with reactive ion etching. The AlON deposition on the recessed gate structures was found to mitigate the damage of recess etching on the GaN and AlGaN surfaces, enabling a simple gate recess process in the device fabrication. Consequently, a high field effect mobility of 259 cm2 V 1 s 1, together with normally off operation, was achieved for the recessed gate AlGaN/GaN MOS HFETs with the AlON gate insulator. Temperature dependence of the transconductance of the fabricated devices revealed that carrier transport in the channel was mostly dominated by phonon scattering, indicating excellent interface quality between the AlON insulator and the recess etched AlGaN surfaces.", "author_names": [ "Takuji Hosoi", "Kenta Watanabe", "Mikito Nozaki", "Takahiro Yamada", "Takayoshi Shimura", "Heiji Watanabe" ], "corpus_id": 182006786, "doc_id": "182006786", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Mobility enhancement in recessed gate AlGaN/GaN MOS HFETs using an AlON gate insulator", "venue": "Japanese Journal of Applied Physics", "year": 2019 } ]

[ { "abstract": "Inferring behavioral models (e.g. state machines) of software systems is an important element of re engineering activities. Model inference techniques can be categorized as active or passive learning, constructing models by (dynamically) interacting with systems or (statically) analyzing traces, respectively. Application of those techniques in the industry is, however, hindered by the trade off between learning time and completeness achieved (active learning) or by incomplete input logs (passive learning) We investigate the learning time/completeness achieved trade off of active learning with a pilot study at ASML, provider of lithography systems for the semiconductor industry. To resolve the trade off we advocate extending active learning with execution logs and passive learning results.We apply the extended approach to eighteen components used in ASML TWINSCAN lithography machines. Compared to traditional active learning, our approach significantly reduces the active learning time. Moreover, it is capable of learning the behavior missed by the traditional active learning approach.", "author_names": [ "Nan Yang", "Kousar Aslam", "Ramon R H Schiffelers", "Leonard Lensink", "Dennis Hendriks", "Loek G Cleophas", "Alexander Serebrenik" ], "corpus_id": 84182735, "doc_id": "84182735", "n_citations": 12, "n_key_citations": 0, "score": 1, "title": "Improving Model Inference in Industry by Combining Active and Passive Learning", "venue": "2019 IEEE 26th International Conference on Software Analysis, Evolution and Reengineering (SANER)", "year": 2019 }, { "abstract": "", "author_names": [ "Dawn McKinney", "Alex D Edgcomb", "Roman L Lysecky", "Frank Vahid" ], "corpus_id": 225710814, "doc_id": "225710814", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Improving Pass Rates by Switching from a Passive to an Active Learning Textbook in CS0", "venue": "", "year": 2020 }, { "abstract": "This study aims to investigate the effect of the collaborative learning on improving the students' potential when dealing with the active voice and the passive voice in English. To achieve this aim, the researchers conducted this study on the eighth graders in Qalqilia district in Palestine. The treatment was applied to 50 male and female students who were randomly selected from all the district schools. The researchers divided the sample into two groups of 25 students each (a control group and an experimental group) The groups were given the same material about the passive voice and the active voice. The students in the control group were taught the use of the passive voice and the active voice through the traditional method while the students in the experimental group were taught the use of the passive voice and the active voice through the collaborative learning method. The researchers illustrated the collaborative learning principles to the teacher of the experimental group. For details see Appendix III, P23 24. During the second semester 2006 2007 and before applying the collaborative method, the researchers gave the two groups the same test to make sure that they were equivalent. They administered the same test to the two groups after applying the collaborative method. The findings of the study showed that there was a significant difference between the experimental and the control groups in favor of the experimental group, which means that the collaborative learning strategy was more effective in improving students' learning of the active and passive voice. Based on these findings, the researchers recommended that teachers be advised to adopt the collaborative learning strategy that focuses on the learner who is considered as the foundation stone of the whole teaching and learning process.", "author_names": [ "Ahmed Awad", "Khalaf Al-Makhzoomi" ], "corpus_id": 59216803, "doc_id": "59216803", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "The Effect of Collaborative Strategy on Improving Students' Potentials in learning Active Voice and Passive Voice in English", "venue": "", "year": 2009 }, { "abstract": "Context aware learning spaces (CALSs) utilise resources of the surrounding context in the learning process. UFractions is a CALS combining a storytelling game and fraction rods for mathematics education, and it was developed for the South African context and later taken to Finland. We divide technology integration into active and passive integration according to the role of technology in the process. In passive integration the technology is integrated into the CALS so that it does not disturb the learner and the context. In active integration the technology integrates resources into the CALS and makes the system adaptive to contextual changes. We analysed, by a mixed method approach, the need for active and passive integration in UFractions in Finland and South Africa. We identified sixteen disturbance factors which had negative effects on the users of UFractions. The results indicate that by improving active and passive integration in UFractions, disturbance factors can be diminished.", "author_names": [ "Teemu Henrikki Laine", "Erkki Sutinen", "Mike S Joy", "Eeva Nygren" ], "corpus_id": 59930502, "doc_id": "59930502", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Active and passive technology integration in context aware learning spaces", "venue": "", "year": 2011 }, { "abstract": "Abstract Recreation students lack some skills and competencies at the beginning of their careers. This may be related to passive learning settings with limited or no exposure to practical experiences during training. To gain the required competencies, students need to be exposed to active learning processes. The focus of this study was to establish if an experiential learning teaching approach, implemented in a recreation degree programme, could develop students' graduate attributes. A holistic single case, case study design employing a convergent parallel mixed method pre post test design was used. An adapted Twin Cycle Experiential Learning Model (TCELM) was applied in a final year recreation module at a higher education institution. The Review of Personal Effectiveness and Locus of Control (ROPELOC) questionnaire and a self report competency assessment survey were completed by 28 students at the beginning and end of the semester. Qualitative data included student reflections and focus group interviews. Data were analysed using descriptive statistics and inductive coding. The ROPELOC revealed statistical significant improvement in the student's leadership skills (p 0.04) and their overall effectiveness (p 0.01) Research skills (p 0.00) adaptability (p 0.00) leadership skills (p 0.00) personal qualities (p 0.02) and knowledge of the profession (p 0.00) were competencies that increased significantly over the semester. From the qualitative data several categories, linked to graduate attributes required by recreation professionals, emerged. Knowledge of the profession was the most mentioned category. These results support the view that an experiential learning teaching approach is beneficial in the preparation of recreation graduates, and should form the teaching foundation for recreation in higher education.", "author_names": [ "Cornelia M Schreck", "Johannes Theron Weilbach", "Gerda Marie Reitsma" ], "corpus_id": 210453097, "doc_id": "210453097", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Improving graduate attributes by implementing an experiential learning teaching approach: A case study in recreation education", "venue": "", "year": 2020 }, { "abstract": "Modern humanoid robots include not only active compliance but also passive compliance. Apart from improved safety and dependability, availability of passive elements, such as springs, opens up new possibilities for improving the energy efficiency. With this in mind, this paper addresses the challenging open problem of exploiting the passive compliance for the purpose of energy efficient humanoid walking. To this end, we develop a method comprising two parts: an optimization part that finds an optimal vertical center of mass trajectory, and a walking pattern generator part that uses this trajectory to produce a dynamically balanced gait. For the optimization part, we propose a reinforcement learning approach that dynamically evolves the policy parametrization during the learning process. By gradually increasing the representational power of the policy parametrization, it manages to find better policies in a faster and computationally efficient way. For the walking generator part, we develop a variable center of mass height ZMP based bipedal walking pattern generator. The method is tested in real world experiments with the bipedal robot COMAN and achieves a significant 18% reduction in the electric energy consumption by learning to efficiently use the passive compliance of the robot.", "author_names": [ "Petar Kormushev", "Barkan Ugurlu", "Darwin Gordon Caldwell", "Nikolaos G Tsagarakis" ], "corpus_id": 53474600, "doc_id": "53474600", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Learning to exploit passive compliance for energy efficient gait generation on a compliant humanoid", "venue": "Auton. Robots", "year": 2019 }, { "abstract": "In India, traditional learning approaches in universities follow passive learning and instruction based studies. The demand for evidence based instructional and interactive active learning processes increases with the advancement in technology. To improve the quality of teaching and student performance, Laureate International University network has taken a unique initiative by applying an iterative and evidence based active learning process in small groups at the University of Petroleum and Energy Studies, Dehradun for the Postgraduate Certificate in Academic Practice program. In this study, active learning processes with digital devices (mobile devices) and digital technologies (modeling tools, simulation, and online resources) having virtual small to medium strength classrooms are integrated into various scenarios with different levels of education. This has been found to be useful in improving student performance during the COVID 19 pandemic. The proposed process applies both traditional and active learning processes with the provision to use mobile devices for digital content. This process also involves teachers attending a Bootcamp, over a 2 month period, consisting of four modules in which they learn about and use digital content that will then be applied in their courses. Results show that the active learning process is of great benefit to students over traditional learning, and it provides a 30% improvement in student's grades. Further, it is observed that long term learning average marks increase by 66.9% in two engineering subjects. The simulation based experimentations are conducted to engage students and faculty members in active learning and simulation learning processes. It shows that the proposed approach (active learning) improves students' learning abilities as compared to the traditional approach.", "author_names": [ "Ravi Singhal", "Adarsh Kumar", "Harvinder Singh", "Stephanie Fuller", "Sukhpal Singh Gill" ], "corpus_id": 226360231, "doc_id": "226360231", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Digital device based active learning approach using virtual community classroom during the COVID 19 pandemic", "venue": "", "year": 2020 }, { "abstract": "For the problem that large scale labeled samples are not easy to acquire in the course of Support Vector Machines (SVMs) training, a Semi Supervised Active Learning Algorithm for SVMs (QTB ASVM) is proposed in the paper, which efficiently combines the semi supervised learning based on Tri Training and active learning based on Query By Committee (QBC) with SVMs. With this method, QBC active learning is used to select the samples which are the most valuable to current SVM classifier, and Tri Training is used to exploit useful information that remains in the unlabeled samples. The experimental results show that the proposed approach can considerably reduce the labeled samples and costs compared to the SVMs which is either not applied with semi supervised learning or active learning or applied with only one of them, and at the same time it can ensure that the accurate classification performance is kept as the passive SVM, while improving generalization performance and also expediting the SVM training.", "author_names": [ "Hailong Xu", "Longyue Li", "Pengsong Guo" ], "corpus_id": 229457151, "doc_id": "229457151", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Semi supervised active learning algorithm for SVMs based on QBC and tri training", "venue": "J. Ambient Intell. Humaniz. Comput.", "year": 2021 }, { "abstract": "Microsurgical procedures, such as petroclival meningioma resection, require careful surgical actions in order to remove tumor tissue, while avoiding brain and vessel damaging. Such procedures are currently performed under microscope magnification. Robotic tools are emerging in order to filter surgeons' unintended movements and prevent tools from entering forbidden regions such as vascular structures. The present work investigates the use of a handheld robotic tool (Micron) to automate vessel avoidance in microsurgery. In particular, we focused on vessel segmentation, implementing a deep learning based segmentation strategy in microscopy images, and its integration with a feature based passive 3D reconstruction algorithm to obtain accurate and robust vessel position. We then implemented a virtual fixture based strategy to control the handheld robotic tool and perform vessel avoidance. Clay vascular phantoms, lying on a background obtained from microscopy images recorded during petroclival meningioma surgery, were used for testing the segmentation and control algorithms. When testing the segmentation algorithm on 100 different phantom images, a median Dice similarity coefficient equal to 0.96 was achieved. A set of 25 Micron trials of 80 s in duration, each involving the interaction of Micron with a different vascular phantom, were recorded, with a safety distance equal to 2 mm, which was comparable to the median vessel diameter. Micron's tip entered the forbidden region 24% of the time when the control algorithm was active. However, the median penetration depth was 16.9 mm, which was two orders of magnitude lower than median vessel diameter. Results suggest the system can assist surgeons in performing safe vessel avoidance during neurosurgical procedures.", "author_names": [ "Sara Moccia", "Simone Foti", "Arpita Routray", "Francesca Prudente", "Alessandro Perin", "Raymond F Sekula", "Leonardo S Mattos", "Jeffrey R Balzer", "Wendy K Fellows-Mayle", "Elena De Momi", "Cameron N Riviere" ], "corpus_id": 51632341, "doc_id": "51632341", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Toward Improving Safety in Neurosurgery with an Active Handheld Instrument", "venue": "Annals of Biomedical Engineering", "year": 2018 }, { "abstract": "Developing high throughput and high performance phenotyping algorithms is critical to the secondary use of electronic health records for clinical research. Supervised machine learning based methods have shown good performance, but often require large annotated datasets that are costly to build. Simulation studies have shown that active learning (AL) could reduce the number of annotated samples while improving the model performance when assuming that the time of labeling each sample is the same (i.e. cost insensitive) In this study, we proposed a cost sensitive AL (CostAL) algorithm for clinical phenotyping, using the identification of breast cancer patients as a use case. CostAL implements a linear regression model to estimate the actual time required for annotating each individual sample. We recruited two annotators to manual review medical records of 766 potential breast cancer patients and recorded the actual time of annotating each sample. We then compared CostAL, AL, and passive learning (PL, aka random sampling) using this annotated dataset and generated learning curves for each method. Our experimental results showed that CostAL achieved the highest area under the curve (AUC) score among the three algorithms (PL, AL, and CostAL are 0.784, 0.8501, and 0.8673 for user 1 and 0.8006, 0.8806 and 0.9006 for user 2) To achieve an accuracy of 0.94, AL and CostAL could save 36% and 60% annotation time for user 1 and 53% and 70% annotation time for user 2, when they were compared with PL, indicating the value of cost sensitive AL approaches.", "author_names": [ "Zongcheng Ji", "Qiang Wei", "Amy Franklin", "Trevor A Cohen", "Hua Xu" ], "corpus_id": 195756370, "doc_id": "195756370", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Cost sensitive Active Learning for Phenotyping of Electronic Health Records.", "venue": "AMIA Joint Summits on Translational Science proceedings. AMIA Joint Summits on Translational Science", "year": 2019 } ]

[ { "abstract": "To evaluate the reliability of endure high voltage when IGBT is turned off and eliminate the defective devices, HTRB (High Temperature Reverse Bias) test is one of the necessary tests for IGBT before it's produced. According to the IEC standard, DUTs (Device Under Test) are usually blocked, and bear forward bias voltage, which is preferably 80% of VCESmax. During the HTRB test, DUT junction temperature should be set at maximum virtual junction temperature Tvj(max) which is usually between 125degC to 150degC. Due to high voltage, even though the leakage current is very low, high power semiconductor devices generate dissipated power during HTRB test, which lead to junction temperature increase. And to access the reliability accurately, the rise of temperature cannot be neglected. To insure the test is carry out at standard temperature, this paper monitors DUTs junction temperature by using leakage current as a TSEP (Temperature Sensitive Electrical Parameter) The experiment proofs that higher the junction temperature is, the more accurate the measure results will be, in the operating temperature range. In this paper, thermal resistance measurement is used to evaluate the validity of this method.", "author_names": [ "Chunsheng Guo", "Wenyi Cai", "Jinyuan Li", "Sijin Wang", "Lei Wei", "Yaosheng Li" ], "corpus_id": 199179118, "doc_id": "199179118", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Online IGBT Temperature Measurement via Leakage Current in HTRB Test", "venue": "Journal of Physics: Conference Series", "year": 2019 }, { "abstract": "High thermal and electrical stress, over a period of time tends to deteriorate the health of power electronic switches. Being a key element in any high power converter systems, power switches, such as insulated gate bipolar junction transistors (IGBTs) and metal oxide semiconductor field effect transistors, are constantly monitored to predict when and how they might fail. A huge fraction of research efforts involves the study of power electronic device reliability and development of novel techniques with higher accuracy in the health estimation of such devices. Until today, no other existing technique can determine the number of lifted bond wires and their locations in a live IGBT module, although this information is extremely helpful to understand the overall state of health of an IGBT power module. Through this article, a new method for online condition monitoring of IGBTs and IGBT modules using spread spectrum time domain reflectometry has been proposed. Unlike traditional methods, this research work concentrates at the gate terminals (low voltage) of the device instead of looking at the collector side. In addition, the RL equivalent circuit to represent a bond wire has been developed for the device under test and simulated in CST Studio Suite to measure the reflection amplitudes. Experimental results were obtained using a prototype reflectometry hardware, and both the simulation and experimental results have been compared. These results prove that a single measurement is sufficient to predict the failure of the device instead of looking at the traditional precursor parameter (VCEON) With only two sets of measurements, it is possible to locate the aged device inside a module and detect the number of bond wire liftoffs associated with that device.", "author_names": [ "Abu Hanif", "Douglas DeVoto", "Faisal Khan" ], "corpus_id": 213754702, "doc_id": "213754702", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Bond Wire Damage Detection and SOH Estimation of a Dual Pack IGBT Power Module Using Active Power Cycling and Reflectometry", "venue": "IEEE Transactions on Power Electronics", "year": 2020 }, { "abstract": "In this paper, we studied the current flow mechanism of PPI (Press Pack IGBT) module under short circuit condition in VSC HVDC application. Through the anatomical analysis of PPI modules tested in different current duration, the change process of the faulty chip and packaging materials was observed. The concept of \"heat infection\" between subunits in a faulty PPI module was proposed, which means the remaining good chips fail due to heat transmission from the faulty chip. Combining the experimental result and simulation analysis, we find that explosion proof ability is the primary condition for a failed PPI module to have long term flow capability under short circuit condition. Meanwhile, the selection of packaging materials and the thickness of the bypass structure must be fully considered, in order to avoid heat concentration and fusing of internal materials.", "author_names": [ "Zhen Wang", "Han Li", "Chao-qun Wan", "Haihui Luo", "YaDong Ren", "Gui Chang", "Yu-Ze Chen", "TingChang Shi", "Guozhong Dong" ], "corpus_id": 230513650, "doc_id": "230513650", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research on The Current Flow Mechanism of Press Pack IGBT under Short Circuit Condition in VSC HVDC System", "venue": "2020 4th International Conference on HVDC (HVDC)", "year": 2020 }, { "abstract": "Recent field failure reports have showed that power cell faults represent the highest contributor to overall CHB converter failure rates. A big portion of these failures are related to power switches, capacitors, gate driver and control circuit boards. Focusing on power switches faults, they normally fail as short circuit or open circuit. Short circuits are dangerous events, however, there is standard method for fast neutralization. On the other hand, open circuit faults are not as fatal as short circuits. Nonetheless, in some situations, the load could not tolerate current imbalance caused by open circuit faults requiring an effective detection and identification method. In general, IGBT open circuit faults are more difficult to detect, and there is no standard method for detection. As a result, there is an industry need for detection, classification, and identification techniques that can perform effectively under different motor loading conditions. In this paper, a proposed method for classifying cell faults caused by IGBT open circuit is presented. Simulation results are provided in order to evaluate the performance of the proposed method.", "author_names": [ "Ahmed Abuelnaga", "Mehdi Narimani" ], "corpus_id": 209321128, "doc_id": "209321128", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Open Circuit IGBT Fault Classification using Phase Current in a CHB Converter", "venue": "IECON 2019 45th Annual Conference of the IEEE Industrial Electronics Society", "year": 2019 }, { "abstract": "Aiming at the fatigue failure of IGBT module package, the failure evolution process of the weak link bond wire and solder layer is studied. For bond wire failure, the evolution process of bond wire cracks is studied. The variation law in the evolution process is analyzed by the bond wire resistance as the characterization parameter of crack evolution. For solder layer failure, the growth and evolution process of solder layer voids is studied. The effects of solder layer voids on the junction temperature and stress of the module are analyzed, and two void growth modes are given. Taking the thermal resistance as the characterization parameter of the void evolution, the variation law of the thermal resistance parameter in the evolution process is analyzed. The results show that the crack has little effect on the resistance at the initial stage of the bond wire crack, as the crack grows to a certain extent, the equivalent resistance will expand rapidly, causing the module to fail; under the void growth fusion modes, the effect of the void on the thermal resistance increases rapidly as the progress of the void fusion increases.", "author_names": [ "Shengxue Tang", "Dong Chen", "Fang Yao", "Zhankai Li" ], "corpus_id": 216587842, "doc_id": "216587842", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Package Fatigue Failure Evolution of IGBT Modules", "venue": "2019 IEEE 3rd International Electrical and Energy Conference (CIEEC)", "year": 2019 }, { "abstract": "In order to improve the heat dissipation capability of high power press pack insulated gate bipolar transistor (PP IGBT) the nanosilver paste was utilized to package a single 3.3 kV/50 A PP IGBT chip; we called it sintered pack IGBT (SP IGBT) in this letter and revealed the reliability of such a device based on a power cycling test (PCT) The test results show that the ON state voltage (Vce) of SP IGBT sharply increased to 9.5 V after 5500 cycles, and then the device emerged with a special short circuit failure. The huge heat generated at the moment of device failure caused the sintered nanosilver layer to melt and then squeezed it out by the external pressure, and the melt silver paste directly connected the collector molybdenum layer to the emitter of SP IGBT die, which is different from the short circuit failure of fully PP IGBT due to being electrically broken down. The failed device is analyzed by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) the failure mechanism is explained by a finite element analysis, and such work is helpful for the package crafts improvement on the press pack power modules.", "author_names": [ "Helong Li", "Haiyang Long", "Ran Yao", "Xiao Wang", "Yi Zhong", "Renze Yu", "Jinyuan Li" ], "corpus_id": 210695294, "doc_id": "210695294", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A Study on the Failure Evolution to Short Circuit of Nanosilver Sintered Press Pack IGBT", "venue": "IEEE Transactions on Components, Packaging and Manufacturing Technology", "year": 2020 }, { "abstract": "Abstract An epoxy molded package is compared with a silicone gel module with IGBTs chips in short circuit failure modes with respect to critical energy, I2Tmelting and explosion energy capabilities. Special importance was attached to \"ohmic mode\" assessment and ageing of the failed chips. The molded technology yields a very low and stable Rsc 1000 h) also exhibit an acceptable drift of the Rsc property", "author_names": [ "Frederic Richardeau", "Zhifeng Dou", "Emmanuel Sarraute", "Jean-Marc Blaquiere", "Didier Flumian" ], "corpus_id": 44472958, "doc_id": "44472958", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Comparison of IGBT short circuit failure \"ohmic mode\" Epoxy molded package versus silicone gel module for new fail safe and interruptible power converters", "venue": "Microelectron. Reliab.", "year": 2011 }, { "abstract": "Dielectric liquids are incompressible, able to fill voids and have selfhealing effect and hence are being considered as alternative encapsulation materials to establish power electronics at ambient high pressure at subsea conditions. In a long term endurance test, insulated gate bipolar transistor (IGBT) chips subjected to 6.5 kV DC stress in dielectric oil environment was reported to have failed after less than one week in operation. A critical look at the failed objects revealed contamination fibres at the surface and around the high field regions. This paper presents the numerical simulation of field distribution around a conducting fibre at the surface of the IGBT chip. It also evaluates the influence of the nature of the encapsulation material on the integrity of power electronic modules using a long term experiment at a medium elevated temperature for high and low relative humidity operated close to service load using IGBT relevant chips. Finite element method (FEM) calculations show how the high field region can be shielded from impurities that can easily trigger partial discharge (PD) and breakdown. The simulation suggests that coating the surface of the module with a thin polymer layer with a thickness of 20 mm or more could be sufficient to improve the reliability of the encapsulation system. Additional polymer coat with thickness 27 mm on the chip made the system survive without failure for 67 weeks under test and dry operating condition. Meanwhile, thick coating such as silicone gel protected the object longer under higher relative humidity.", "author_names": [ "Abdelghaffar Amoka Abdelmalik", "Knut Brede Liland" ], "corpus_id": 229462867, "doc_id": "229462867", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Electric field enhancement control in active junction of IGBT power module", "venue": "", "year": 2020 }, { "abstract": "High thermal and electrical stress, over a period of time tends to deteriorate the health of power electronic switches. Being a key element in any high power converter systems, power switches such as Insulated Gate Bipolar Junction Transistors (IGBTs) and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) are constantly monitored to predict when and how they might fail. A huge fraction of research efforts involves the study of power electronic device reliability and development of novel techniques with higher accuracy in health estimation of such devices. Through this paper, a new method for online condition monitoring of IGBTs and IGBT modules using spread spectrum time domain reflectometry (SSTDR) has been proposed. Unlike traditional methods, this research work concentrates at the gate terminals (low voltage) of the device instead of looking at the collector side. The IGBT collector emitter ON voltage or VCEON was chosen as the failure precursor parameter as the reference, and the auto correlated magnitudes of the SSTDR signal for the new and the aged IGBTs were plotted and compared.", "author_names": [ "Abu Hanif", "Swagato Das", "Faisal Khan" ], "corpus_id": 5040184, "doc_id": "5040184", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Active power cycling and condition monitoring of IGBT power modules using reflectometry", "venue": "2018 IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2018 }, { "abstract": "In this paper, a fast and practical method is proposed for open circuit (OC) fault diagnosis (FD) in a three phase quasi Z source inverter (q ZSI) Compared with the existing fast OC FD techniques in three phase voltage source inverters, this method is more cost effective since no ultrafast processor or high speed measurement is required. Additionally, the method is independent of the load condition. The proposed method is only applicable to Z source family inverters and is based on observing the effect of shoot through intervals on the system variables during switching periods. The proposed algorithm includes two consecutive stages: OC detection and fault location identification. When both stages of the OC FD algorithm are done, a redundant leg is activated and utilized instead of the failed leg. The accuracy of the proposed method is confirmed by the experimental results from a low voltage q ZSI prototype.", "author_names": [ "Mokhtar Yaghoubi", "Javad Shokrollahi Moghani", "Negar Noroozi", "Mohammad Reza Zolghadri" ], "corpus_id": 54450762, "doc_id": "54450762", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "IGBT Open Circuit Fault Diagnosis in a Quasi Z Source Inverter", "venue": "IEEE Transactions on Industrial Electronics", "year": 2019 } ]

[ { "abstract": "We present an all optical neuron that utilizes a logistic sigmoid activation function, using a Wavelength Division Multiplexing (WDM) input weighting scheme. The activation function is realized by means of a deeply saturated differentially biased Semiconductor Optical Amplifier Mach Zehnder Interferometer (SOA MZI) followed by a SOA Cross Gain Modulation (XGM) gate. Its transfer function is both experimentally and theoretically analyzed, showing excellent agreement between theory and experiment and an almost perfect fitting with a logistic sigmoid function. The optical sigmoid transfer function is then exploited in the experimental demonstration of a photonic neuron, demonstrating successful thresholding over a 100psec long pulse sequence with 4 different weighted and summed power levels.", "author_names": [ "George Mourgias-Alexandris", "Apostolos Tsakyridis", "Nikolaos Passalis", "Anastasios Tefas", "Konstantinos Vyrsokinos", "Nikos Pleros" ], "corpus_id": 126890622, "doc_id": "126890622", "n_citations": 49, "n_key_citations": 7, "score": 1, "title": "An all optical neuron with sigmoid activation function.", "venue": "Optics express", "year": 2019 }, { "abstract": "We present an all optical neuron that utilizes a logistic sigmoid activation function, using a Wavelength Division Multiplexing (WDM) input weighting scheme. The activation function is realized by means of a deeply saturated differentially biased Semiconductor Optical Amplifier Mach Zehnder Interferometer (SOA MZI) followed by a SOA Cross Gain Modulation (XGM) gate. Its transfer function is both experimentally and theoretically analyzed, showing excellent agreement between theory and experiment and an almost perfect fitting with a logistic sigmoid function. The optical sigmoid transfer function is then exploited in the experimental demonstration of a photonic neuron, demonstrating successful thresholding over a 100psec long pulse sequence with 4 different weighted and summed power levels. (c) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement", "author_names": [ "M G", "", "A -", "T A", "Prabhat N", "V K" ], "corpus_id": 197680080, "doc_id": "197680080", "n_citations": 8, "n_key_citations": 2, "score": 0, "title": "An all optical neuron with sigmoid activation function", "venue": "", "year": 2019 }, { "abstract": "With the recent successes of neural networks (NN) to perform machine learning tasks, photonic based NN designs may enable high throughput and low power neuromorphic compute paradigms since they bypass the parasitic charging of capacitive wires. Thus, engineering data information processors capable of executing NN algorithms with high efficiency is of major importance for applications ranging from pattern recognition to classification. Our hypothesis is therefore, that if the time limiting electro optic conversion of current photonic NN designs could be postponed until the very end of the network, then the execution time of the photonic algorithm is simple the delay of the time of flight of photons through the NN, which is on the order of picoseconds for integrated photonics. Exploring such all optical NN, in this work we discuss two independent approaches of implementing the optical perceptrons nonlinear activation function based on nanophotonic structures exhibiting i) induced transparency and ii) reverse saturated absorption. Our results show that the all optical nonlinearity provides about 3 and 7 dB extinction ratio for the two systems considered, respectively, and classification accuracies of an exemplary MNIST task of 97% and near 100% are found, which rivals that of software based trained NNs, yet with ignored noise in the network. Together with a developed concept for an all optical perceptron, these findings point to the possibility of realizing pure photonic NNs with potentially unmatched throughput and even energy consumption for next generation information processing hardware.", "author_names": [ "Mario Miscuglio", "Armin Mehrabian", "Zibo Hu", "Shaimaa I H Azzam", "Jonathan K George", "Alexander V Kildishev", "Matthew Pelton", "Volker J Sorger" ], "corpus_id": 53519936, "doc_id": "53519936", "n_citations": 90, "n_key_citations": 0, "score": 0, "title": "All optical Nonlinear Activation Function for Photonic Neural Networks", "venue": "", "year": 2018 }, { "abstract": "We experimentally demonstrate an optical neuron using an optical logistic Sigmoid activation function. Successful thresholding at 4 different power levels was achieved yielding a 100% improvement compared to state of the art, employing a sequence of 100psec long pulses.", "author_names": [ "George Mourgias-Alexandris", "Apostolos Tsakyridis", "Nikolaos Passalis", "Anastasios Tefas", "Nikos Pleros" ], "corpus_id": 115203401, "doc_id": "115203401", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Experimental Demonstration of an Optical Neuron with a Logistic Sigmoid Activation Function", "venue": "2019 Optical Fiber Communications Conference and Exhibition (OFC)", "year": 2019 }, { "abstract": "Recently integrated optics has become an intriguing platform for implementing machine learning algorithms and inparticular neural networks. Integrated photonic circuits can straightforwardly perform vector matrix multiplicationswith high efficiency and low power consumption by using weighting mechanism through linear optics. Although,this can not be said for the activation function which requires either nonlinear optics or an electro optic module withan appropriate dynamic range. Even though all optical nonlinear optics is potentially faster, its current integrationis challenging and is rather inefficient. Here we demonstrate an electro absorption modulator based on an IndiumTin Oxide layer, whose dynamic range is used as nonlinear activation function of a photonic neuron. The nonlinearactivation mechanism is based on a photodiode, which integrates the weighed products, and whose photovoltage drivesthe elecro absorption modulator. The synapse and neuron circuit is then constructed to execute a 200 node MNISTclassification neural network used for benchmarking the nonlinear activation function and compared with an equivalentelectronic module.", "author_names": [ "Rubab Amin", "Thomas Ferreira de Lima", "Alexander N Tait", "Jacob B Khurgin", "Mario Miscuglio", "Bhavin J Shastri", "Paul R Prucnal", "Tarek A El-Ghazawi", "Volker J Sorger" ], "corpus_id": 173990360, "doc_id": "173990360", "n_citations": 40, "n_key_citations": 2, "score": 0, "title": "ITO based electro absorption modulator for photonic neural activation function", "venue": "APL Materials", "year": 2019 }, { "abstract": "Nerve growth factor/tropomyosin receptor kinase A (NGF/TrkA) signaling plays a key role in neuronal development, function, survival, and growth. The pathway is implicated in neurodegenerative disorders including Alzheimer's disease, chronic pain, inflammation, and cancer. NGF binds the extracellular domain of TrkA, leading to the activation of the receptor's intracellular kinase domain. As TrkA signaling is highly dynamic, mechanistic studies would benefit from a tool with high spatial and temporal resolution. Here we present the design and evaluation of four strategies for light inducible activation of TrkA in the absence of NGF. Our strategies involve the light sensitive protein Arabidopsis cryptochrome 2 and its binding partner CIB1. We demonstrate successful recapitulation of native NGF/TrkA functions by optical induction of plasma membrane recruitment and homo interaction of the intracellular domain of TrkA. This approach activates PI3K/AKT and Raf/ERK signaling pathways, promotes neurite growth in PC12 cells, and supports survival of dorsal root ganglion neurons in the absence of NGF. This ability to activate TrkA using light bestows high spatial and temporal resolution for investigating NGF/TrkA signaling.", "author_names": [ "Liting Duan", "Jen M Hope", "Shunling Guo", "Qunxiang Ong", "Amaury Francois", "Luke Kaplan", "Gregory Scherrer", "Bianxiao Cui" ], "corpus_id": 49699074, "doc_id": "49699074", "n_citations": 26, "n_key_citations": 1, "score": 0, "title": "Optical Activation of TrkA Signaling.", "venue": "ACS synthetic biology", "year": 2018 }, { "abstract": "Neural prostheses can restore meaningful function to paralysed muscles by electrically stimulating innervating motor axons, but fail when muscles are completely denervated, as seen in amyotrophic lateral sclerosis, or after a peripheral nerve or spinal cord injury. Here we show that channelrhodopsin 2 is expressed within the sarcolemma and T tubules of skeletal muscle fibres in transgenic mice. This expression pattern allows for optical control of muscle contraction with comparable forces to nerve stimulation. Force can be controlled by varying light pulse intensity, duration or frequency. Light stimulated muscle fibres depolarize proportionally to light intensity and duration. Denervated triceps surae muscles transcutaneously stimulated optically on a daily basis for 10 days show a significant attenuation in atrophy resulting in significantly greater contractile forces compared with chronically denervated muscles. Together, this study shows that channelrhodopsin 2/H134R can be used to restore function to permanently denervated muscles and reduce pathophysiological changes associated with denervation pathologies.", "author_names": [ "Philippe Magown", "Basavaraj C Shettar", "Ying Zhang", "Victor F Rafuse" ], "corpus_id": 31804800, "doc_id": "31804800", "n_citations": 30, "n_key_citations": 2, "score": 0, "title": "Direct optical activation of skeletal muscle fibres efficiently controls muscle contraction and attenuates denervation atrophy", "venue": "Nature communications", "year": 2015 }, { "abstract": "Artificial activation of neural circuitry through electrical microstimulation and optogenetic techniques is important for both scientific discovery of circuit function and for engineered approaches to alleviate various disorders of the nervous system. However, evidence suggests that neural activity generated by artificial stimuli differs dramatically from normal circuit function, in terms of both the local neuronal population activity at the site of activation and the propagation to downstream brain structures. The precise nature of these differences and the implications for information processing remain unknown. Here, we used voltage sensitive dye imaging of primary somatosensory cortex in the anesthetized rat in response to deflections of the facial vibrissae and electrical or optogenetic stimulation of thalamic neurons that project directly to the somatosensory cortex. Although the different inputs produced responses that were similar in terms of the average cortical activation, the variability of the cortical response was strikingly different for artificial versus sensory inputs. Furthermore, electrical microstimulation resulted in highly unnatural spatial activation of cortex, whereas optical input resulted in spatial cortical activation that was similar to that induced by sensory inputs. A thalamocortical network model suggested that observed differences could be explained by differences in the way in which artificial and natural inputs modulate the magnitude and synchrony of population activity. Finally, the variability structure in the response for each case strongly influenced the optimal inputs for driving the pathway from the perspective of an ideal observer of cortical activation when considered in the context of information transmission. SIGNIFICANCE STATEMENT Artificial activation of neural circuitry through electrical microstimulation and optogenetic techniques is important for both scientific discovery and clinical translation. However, neural activity generated by these artificial means differs dramatically from normal circuit function, both locally and in the propagation to downstream brain structures. The precise nature of these differences and the implications for information processing remain unknown. The significance of this work is in quantifying the differences, elucidating likely mechanisms underlying the differences, and determining the implications for information processing.", "author_names": [ "Daniel C Millard", "Clarissa J Whitmire", "Clare A Gollnick", "Christopher J Rozell", "Garrett B Stanley" ], "corpus_id": 16345929, "doc_id": "16345929", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Electrical and Optical Activation of Mesoscale Neural Circuits with Implications for Coding", "venue": "The Journal of Neuroscience", "year": 2015 }, { "abstract": "We genetically encoded three new caged tyrosine analogues with improved photochemical properties by using an engineered pyrrolysyl tRNA synthetase/tRNACUA pair in bacterial and mammalian cells. We applied the new tyrosine analogues to the photoregulation of firefly luciferase by caging its key tyrosine residue, Tyr340, and observed excellent off to on light switching. This reporter was then used to evaluate the activation rates of the different light removable protecting groups in live cells. We identified the nitropiperonyl caging group as an excellent compromise between incorporation efficiency and photoactivation properties. To demonstrate applicability of the new caged tyrosines, an important proteolytic enzyme, tobacco etch virus (TEV) protease, was engineered for optical control. The ability to incorporate differently caged tyrosine analogues into proteins in live cells further expands the unnatural amino acid and optogenetic toolbox.", "author_names": [ "Ji Luo", "Jessica Torres-Kolbus", "Jihe Liu", "Alexander Deiters" ], "corpus_id": 5408123, "doc_id": "5408123", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Genetic Encoding of Photocaged Tyrosines with Improved Light Activation Properties for the Optical Control of Protease Function", "venue": "Chembiochem a European journal of chemical biology", "year": 2017 }, { "abstract": "As the most abundant cell type in the central nervous system, astrocyte has been one of main research topics in neuroscience. Although various tools have been developed, at present, there is no tool that allows noninvasive activation of astrocyte in vivo without genetic or pharmacological perturbation. Here we report a noninvasive label free optical method for physiological astrocyte activation in vivo using a femtosecond pulsed laser. We showed the laser stimulation robustly induced astrocytic calcium activation in vivo and further verified physiological relevance of the calcium increase by demonstrating astrocyte mediated vasodilation in the brain. This novel optical method will facilitate noninvasive physiological study on astrocyte function.", "author_names": [ "Myunghwan Choi", "Jonghee Yoon", "Taeyun Ku", "Kyungsun Choi", "Chulhee Choi" ], "corpus_id": 11246009, "doc_id": "11246009", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Label free optical activation of astrocyte in vivo.", "venue": "Journal of biomedical optics", "year": 2011 } ]

[ { "abstract": "Memristor crossbars offer reconfigurable non volatile resistance states and could remove the speed and energy efficiency bottleneck in vector matrix multiplication, a core computing task in signal and image processing. Using such systems to multiply an analogue voltage amplitude vector by an analogue conductance matrix at a reasonably large scale has, however, proved challenging due to difficulties in device engineering and array integration. Here we show that reconfigurable memristor crossbars composed of hafnium oxide memristors on top of metal oxide semiconductor transistors are capable of analogue vector matrix multiplication with array sizes of up to 128 x 64 cells. Our output precision (5 8 bits, depending on the array size) is the result of high device yield (99.8% and the multilevel, stable states of the memristors, while the linear device current voltage characteristics and low wire resistance between cells leads to high accuracy. With the large memristor crossbars, we demonstrate signal processing, image compression and convolutional filtering, which are expected to be important applications in the development of the Internet of Things (IoT) and edge computing.MainMemristor crossbars with array sizes of up to 128 x 64 cells are capable of analogue vector matrix multiplication and can be used for signal processing, image compression and convolutional filtering.", "author_names": [ "Can Li", "Miao Hu", "Yunning Li", "Hao Jiang", "Ning Ge", "Eric Montgomery", "Jiaming Zhang", "Wenhao Song", "Noraica Davila", "Catherine E Graves", "Zhiyong Li", "John Paul Strachan", "Peng Lin", "Zhongrui Wang", "Mark D Barnell", "Qing Wu", "R Stanley Williams", "Jianhua Joshua Yang", "Qiangfei Xia" ], "corpus_id": 189930362, "doc_id": "189930362", "n_citations": 427, "n_key_citations": 16, "score": 2, "title": "Analogue signal and image processing with large memristor crossbars", "venue": "", "year": 2018 }, { "abstract": "We present pyroomacoustics, a software package aimed at the rapid development and testing of audio array processing algorithms. The content of the package can be divided into three main components: an intuitive Python object oriented interface to quickly construct different simulation scenarios involving multiple sound sources and microphones in 2D and 3D rooms; a fast C implementation of the image source model for general polyhedral rooms to efficiently generate room impulse responses and simulate the propagation between sources and receivers; and finally, reference implementations of popular algorithms for beamforming, direction finding, and adaptive filtering. Together, they form a package with the potential to speed up the time to market of new algorithms by significantly reducing the implementation overhead in the performance evaluation step.", "author_names": [ "Robin Scheibler", "Eric Bezzam", "Ivan Dokmanic" ], "corpus_id": 11855208, "doc_id": "11855208", "n_citations": 151, "n_key_citations": 8, "score": 0, "title": "Pyroomacoustics: A Python Package for Audio Room Simulation and Array Processing Algorithms", "venue": "2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)", "year": 2018 }, { "abstract": "Microphone array signal processing based on time frequency masks has been applied successfully to various tasks including source separation, denoising, source localization, and source counting. Aiming to improve the performance of these techniques, here we propose a mask estimation method based on a complex Angular Central Gaussian Mixture Model (cACGMM) for multichannel observed signals. Compared to a conventional complex Watson Mixture Model (cWMM) the proposed cACGMM can model not only rotationally symmetrical but also elliptical distributions. Therefore, the cACGMM can better approximate the distribution of observed data, which is generally not rotationally symmetrical. In source separation simulations with real recorded impulse responses, the cACGMM resulted in an average 1.2 dB improvement of the Signal to Distortion Ratio (SDR) over the cWMM.", "author_names": [ "Nobutaka Ito", "Shoko Araki", "Tomohiro Nakatani" ], "corpus_id": 14213349, "doc_id": "14213349", "n_citations": 55, "n_key_citations": 10, "score": 0, "title": "Complex angular central Gaussian mixture model for directional statistics in mask based microphone array signal processing", "venue": "2016 24th European Signal Processing Conference (EUSIPCO)", "year": 2016 }, { "abstract": "One of the main vulnerabilities of GNSS receivers is their exposure to intentional or unintentional jamming signals, which could even cause service unavailability. Several alternatives to counteract these effects were proposed in the literature, being the most promising those based on multiple antenna architectures. This is specially the case for high grade receivers used in applications requiring reliability and robustness. This article provides an overview of the possible receiver architectures encompassing antenna arrays and the associated signal processing techniques. Emphasis is also put on the most typical implementation issues found when dealing with such technology. A thorough survey is complemented with a set of experiments, including real data processing by a working prototype, which exemplifies the above ideas.", "author_names": [ "Carles Fernandez-Prades", "Javier Arribas", "Pau Closas" ], "corpus_id": 30599071, "doc_id": "30599071", "n_citations": 66, "n_key_citations": 5, "score": 0, "title": "Robust GNSS Receivers by Array Signal Processing: Theory and Implementation", "venue": "Proceedings of the IEEE", "year": 2016 }, { "abstract": "This paper proposes a practical channel estimation for 60 GHz indoor systems with the massive uniform rectangular array at base station. Through antenna array theory, the parameters of each channel path can be decomposed into the angular information and the channel gain information. We first prove that the true direction of arrivals of each uplink path can be extracted via an efficient array signal processing method. Then, the channel gain information could be obtained linearly with small amount of training resources, which significantly reduces the training overhead and the feedback cost. More importantly, the proposed scheme unifies the uplink/downlink channel estimations for both the time duplex division and frequency duplex division systems, making itself particularly suitable for protocol design. Compared with the existing channel estimation algorithms, the newly proposed one does not require any knowledge of channel statistics and can be efficiently deployed by the 2 D fast Fourier transform. Meanwhile, the number of user terminals simultaneously served can be increased from a sophisticatedly designed angle division multiple access scheme. Simulation results are provided to corroborate the proposed studies.", "author_names": [ "Dian Fan", "Feifei Gao", "Gongpu Wang", "Zhangdui Zhong", "Arumugam Nallanathan" ], "corpus_id": 3476431, "doc_id": "3476431", "n_citations": 74, "n_key_citations": 7, "score": 0, "title": "Angle Domain Signal Processing Aided Channel Estimation for Indoor 60 GHz TDD/FDD Massive MIMO Systems", "venue": "IEEE Journal on Selected Areas in Communications", "year": 2017 }, { "abstract": "Abstract Human robot interaction in natural settings requires filtering out the different sources of sounds from the environment. Such ability usually involves the use of microphone arrays to localize, track and separate sound sources online. Multi microphone signal processing techniques can improve robustness to noise but the processing cost increases with the number of microphones used, limiting response time and widespread use on different types of mobile robots. Since sound source localization methods are the most expensive in terms of computing resources as they involve scanning a large 3D space, minimizing the amount of computations required would facilitate their implementation and use on robots. The robot's shape also brings constraints on the microphone array geometry and configurations. In addition, sound source localization methods usually return noisy features that need to be smoothed and filtered by tracking the sound sources. This paper presents a novel sound source localization method, called SRP PHAT HSDA, that scans space with coarse and fine resolution grids to reduce the number of memory lookups. A microphone directivity model is used to reduce the number of directions to scan and ignore non significant pairs of microphones. A configuration method is also introduced to automatically set parameters that are normally empirically tuned according to the shape of the microphone array. For sound source tracking, this paper presents a modified 3D Kalman (M3K) method capable of simultaneously tracking in 3D the directions of sound sources. Using a 16 microphone array and low cost hardware, results show that SRP PHAT HSDA and M3K perform at least as well as other sound source localization and tracking methods while using up to 4 and 30 times less computing resources respectively.", "author_names": [ "Francois Grondin", "Francois Michaud" ], "corpus_id": 54215006, "doc_id": "54215006", "n_citations": 40, "n_key_citations": 7, "score": 0, "title": "Lightweight and Optimized Sound Source Localization and Tracking Methods for Open and Closed Microphone Array Configurations", "venue": "Robotics Auton. Syst.", "year": 2019 }, { "abstract": "Time and frequency modulated arrays have numerous application areas including radar, navigation, and communications. Specifically, a time modulated array can create a beampattern with low sidelobes via connecting and disconnecting the antenna elements from the feed network, while the frequency modulated frequency diverse array produces a range dependent pattern. In this paper, we aim to introduce these advanced arrays to the signal processing community so that more investigations in terms of theory, methods, and applications, can be facilitated. The research progress of time/frequency modulated array studies is reviewed and the most recent advances are discussed. Moreover, potential applications in radar and communications are presented, along with their technical challenges, especially in signal processing aspects.", "author_names": [ "Wen-qin Wang", "Hing Cheung So", "Alfonso Farina" ], "corpus_id": 15797249, "doc_id": "15797249", "n_citations": 105, "n_key_citations": 4, "score": 0, "title": "An Overview on Time/Frequency Modulated Array Processing", "venue": "IEEE Journal of Selected Topics in Signal Processing", "year": 2017 }, { "abstract": "Modern mobile devices are equipped with multiple antennas, which brings various wireless sensing applications such as accurate localization, contactless human detection, and wireless human device interaction. A key enabler for these applications is phased array signal processing, especially Angle of Arrival (AoA) estimation. However, accurate AoA estimation on commodity devices is non trivial due to limited number of antennas and uncertain phase offsets. Previous works either rely on elaborate calibration or involve contrived human interactions. In this paper, we aim to enable practical AoA measurements on commodity off the shelf (COTS) mobile devices. The key insight is to involve users' natural rotation to formulate a virtual spatial temporal antenna array and conduce a relative incident signal of measurements at two orientations. Then by taking the differential phase, it is feasible to remove the phase offsets and derive the accurate AoA of the equivalent incoming signal, while the rotation angle can also be captured by built in inertial sensors. On this basis, we propose Differential MUSIC <italic>D MUSIC</italic> a relative form of the standard MUSIC algorithm that eliminates the unknown phase offsets and achieves accurate AoA estimation on COTS mobile devices with only one rotation. We further extend <italic>D MUSIC</italic> to 3 D space, integrate extra measurements during rotations for higher estimation accuracy, and fortify it in multipath rich scenarios. We prototype <italic>D MUSIC</italic> on commodity WiFi infrastructure and evaluate it in typical indoor environments. Experimental results demonstrate a superior performance with average AoA estimation errors of 13<inline formula> <tex math notation=\"LaTeX\"\\circ}/tex math><alternatives><inline graphic xlink:href=\"qian ieq1 2778155.gif\" /alternatives>/inline formula> with only three measurements and 5<inline formula><tex math notation=\"LaTeX\" \\circ}/tex math><alternatives><inline graphic xlink:href=\"qian ieq2 2778155.gif\"/alternatives> /inline formula> with at most 10 measurements. Requiring no modifications or calibration, <italic>D MUSIC</italic> is envisioned as a promising scheme for practical AoA estimation on COTS mobile devices.", "author_names": [ "Kun Qian", "Chenshu Wu", "Zheng Yang", "Zimu Zhou", "Xu Wang", "Yunhao Liu" ], "corpus_id": 49557296, "doc_id": "49557296", "n_citations": 23, "n_key_citations": 2, "score": 0, "title": "Enabling Phased Array Signal Processing for Mobile WiFi Devices", "venue": "IEEE Transactions on Mobile Computing", "year": 2018 }, { "abstract": "This article investigates a kind of method to measure the wind speed and the wind direction, which is based on arc ultrasonic sensor array and combined with array signal processing algorithm. In the proposed method, a new arc ultrasonic array structure is introduced and the array manifold is derived firstly. On this basis, the measurement of the wind speed and the wind direction is analyzed and discussed by means of the basic idea of the classic MUSIC (Multiple Signal Classification) algorithm, which achieves the measurements of the 360deg wind direction with resolution of 1deg and 0 60m/s wind speed with resolution of 0.1m/s. The implementation of the proposed method is elaborated through the theoretical derivation and corresponding discussion. Besides, the simulation experiments are presented to show the feasibility of the proposed method. The theoretical analysis and simulation results indicate that the proposed method has superiority on anti noise performance and improves the wind measurement accuracy.", "author_names": [ "Xinbo Li", "Haixin Sun", "Wei Gao", "Yaowu Shi", "Guojun Liu", "Yue Wu" ], "corpus_id": 38102922, "doc_id": "38102922", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Wind speed and direction measurement based on arc ultrasonic sensor array signal processing algorithm.", "venue": "ISA transactions", "year": 2016 }, { "abstract": "In this paper, we address the problem of sparsity inducing direction of arrival (DOA) estimation in the context of array covariance vectors when a recently proposed nested array structure is utilized. The proposed approach is based on a Sparse Bayesian learning (SBL) perspective while the off grid effects inherent in traditional sparse recovery algorithms are taken into account simultaneously. Specifically, the notable advantages of the developed approach can be attributed to two aspects. First, through a linear transformation, the unknown noise variance can be eliminated effectively and the estimation error between the actual and sample covariance matrix can be normalized to an identity matrix, thereby facilitating a noise free sparse representation. Second, a computationally tractable polynomial rooting procedure is introduced to calculate the discretized sampling grid error one by one based on the reconstructed spatial power spectrum, thus this novel algorithm can maintain high estimation accuracy even under a coarse sampling grid. Extensive simulation results finally demonstrate the superiority of the proposed approach in terms of DOA estimation precision and computational efficiency over off the shelves techniques. A sparsity inducing DOA estimation method applied in nested array is proposed.The proposed method is based on a Sparse Bayesian learning perspective.The off grid effects inherent in sparse recovery framework are taken into account.The unknown noise variance can be eliminated easily.The off grid distances can be calculated by using a polynomial rooting procedure.", "author_names": [ "Jie Yang", "Guisheng Liao", "Jun Yu Li" ], "corpus_id": 21706508, "doc_id": "21706508", "n_citations": 34, "n_key_citations": 1, "score": 0, "title": "An efficient off grid DOA estimation approach for nested array signal processing by using sparse Bayesian learning strategies", "venue": "Signal Process.", "year": 2016 } ]

[ { "abstract": "A novel multivariate statistical process monitoring (MSPM) method based on modified independent component analysis (ICA) is proposed. ICA is a multivariate statistical tool to extract statistically independent components from observed data, which has drawn considerable attention in research fields such as neural networks, signal processing, and blind source separation. In this article, some drawbacks of the original ICA algorithm are analyzed and a modified ICA algorithm is developed for the purpose of MSPM. The basic idea of the approach is to use the modified ICA to extract some dominant independent components from normal operating process data and to combine them with statistical process monitoring techniques. Variable contribution plots to the monitoring statistics (T2 and SPE) are also developed for fault diagnosis. The proposed monitoring method is applied to fault detection and diagnosis in a wastewater treatment process, the Tennessee Eastman process, and a semiconductor etch process and is compared with conventional PCA monitoring methods. The monitoring results clearly illustrate the superiority of the proposed method. (c) 2006 American Institute of Chemical Engineers AIChE J, 2006", "author_names": [ "Jong-Min Lee", "S Joe Qin", "In-Beum Lee" ], "corpus_id": 110639708, "doc_id": "110639708", "n_citations": 331, "n_key_citations": 14, "score": 2, "title": "Fault detection and diagnosis based on modified independent component analysis", "venue": "", "year": 2006 }, { "abstract": "In this paper, some drawbacks of both the original independent component analysis (ICA) algorithm and the FastICA algorithm are analyzed as follows: the order of the independent components is difficult to be determined; because of using the Newtonian iteration, FastICA method often leads to local minimum solution, and the suitable source signals are not isolated. To solve these problems, a modified ICA algorithm based on particle swarm optimization (PSO) called PSO ICA is proposed for the purpose of multivariate statistical process monitoring (MSPM) The basic idea of the approach is to use the PSO ICA algorithm to extract some dominant independent components from normal operating process data. The order of independent components is determined according to the role of resumption of the original signal. The proposed monitoring method is applied to fault detection and diagnosis in the Tennessee Eastman process. Applications indicate that PSO ICA effectively captures the independent components.", "author_names": [ "Ying-wei Zhang", "Yang Zhang" ], "corpus_id": 109040021, "doc_id": "109040021", "n_citations": 80, "n_key_citations": 2, "score": 0, "title": "Fault detection of non Gaussian processes based on modified independent component analysis", "venue": "", "year": 2010 }, { "abstract": "Statistical fault detection techniques are able to detect fault and diagnose root cause(s) from the monitored process variables. For complex process operations, it is not feasible to screen all the process variables due to monitoring cost and flooding of alarms. Thus, if a fault is originated from a process variable that is not monitored, conventional statistical techniques are incapable of locating the true root cause. To relax this limitation, a two stage fault diagnosis technique is proposed for process operations. In the first stage, the modified independent component analysis is used for fault detection and to identify the faulty monitored variable. In the second stage, a Bayesian Network model is constructed considering the process variables and their dependence obtained from the process flow diagram. Evidence is then generated at the network node corresponding to the faulty variable identified in the first stage. Subsequently, the network is updated and analyzed using deductive and abductive reason.", "author_names": [ "Hongyang Yu", "F Khan", "Vikram Garaniya" ], "corpus_id": 95978554, "doc_id": "95978554", "n_citations": 52, "n_key_citations": 2, "score": 0, "title": "Modified independent component analysis and Bayesian network based two stage fault diagnosis of process operations", "venue": "", "year": 2015 }, { "abstract": "Abstract Compared to large process faults, the latent and small ones are difficult to be detected. However, the accumulation of these faults may even more harmful to the process. A novel fault detection and diagnosis method is proposed which is based on similarity factor and a variable moving window. The new method is based on the idea that a change of process can be reflected in the distribution of the data, which can be detected more easily by the proposed similarity factor. Meanwhile, it has no Gaussian distribution limitation of the process data, since the mixed similarity factor is introduced. The independent component analysis (ICA) factor and the principal component analysis (PCA) factor are used for similarity comparison for Gaussian and non Gaussian information, respectively. Besides, in order to determine the dynamic step accurately and cut the computation cost, the conventional dynamic method is modified by using autocorrelation analysis. A case study of Tennessee Eastman (TE) benchmark process shows the efficiency of the new proposed method.", "author_names": [ "Zhiqiang Ge", "Zhi-huan Song" ], "corpus_id": 13630259, "doc_id": "13630259", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Latent and small fault detection and diagnosis for dynamic processes", "venue": "", "year": 2008 }, { "abstract": "In this article, we propose a framework to monitor the chatter phenomenon and to diagnose the cause variables of chatter occurred in the hot strip mill process (HSMP) For monitoring chatter, we develop a chatter index (CI) that quantifies chatter to confirm its occurrence. Based on the data classified as normal by the CI, a multivariate statistical process monitoring model for detecting chatter is constructed using the modified independent component analysis (MICA) method. The monitoring results show that the model based on the MICA outperforms other models based on the principal component analysis and independent component analysis. For the diagnosis of the cause variables of detected chatter, various contribution plots can be used. In this article, we develop a relative contribution plot for a more obvious diagnosis than the existing contribution plot. Using this, we diagnose and analyze the cause variables of the detected chatter in the HSMP.", "author_names": [ "Ha-Nui Jo", "Byeong Eon Park", "Yumi Ji", "Dong-Kuk Kim", "Jeong Eun Yang", "In-Beum Lee" ], "corpus_id": 216014729, "doc_id": "216014729", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chatter Detection and Diagnosis in Hot Strip Mill Process With a Frequency Based Chatter Index and Modified Independent Component Analysis", "venue": "IEEE Transactions on Industrial Informatics", "year": 2020 }, { "abstract": "Abstract Dynamic principal component analysis (DPCA) and dynamic independent component analysis (DICA) as the frequently used dimensional reduction methods, have been widely applied to monitor dynamic process. Considering the respective advantages of DPCA and DICA in different data distribution characteristics, this paper proposes a novel process monitoring algorithm named DPCA, DICA and Bayesian Inference (DPCA DICA BI) The main idea of DPCA DICA BI is to put the process variables with same distribution characteristic (Gaussian or non Gaussian) into a block on the basis of the variable normality by Jarque Bera test and then to respectively apply DPCA and DICA in Gaussian and non Gaussian blocks. Finally, to combine the monitoring performance of both blocks, Bayesian inference is employed to make an integrated decision. The DPCA DICA BI as well as PCA, ICA, DPCA, and DICA has been used to a numerical example and Tennessee Eastman process. The simulation results show the superiority of DPCA DICA BI.", "author_names": [ "Jian Huang", "Xuefeng Yan" ], "corpus_id": 119851986, "doc_id": "119851986", "n_citations": 63, "n_key_citations": 2, "score": 0, "title": "Dynamic process fault detection and diagnosis based on dynamic principal component analysis, dynamic independent component analysis and Bayesian inference", "venue": "", "year": 2015 }, { "abstract": "Kernel principal component analysis is a technique applied for monitoring nonlinear processes. However, compute control limit based on Gaussian distribution can deteriorate its performance. Kernel density estimation is applied to solve the aforementioned issue. In conventional KPCA, a kernel based model depends on a single Gaussian kernel function selected empirically, which means a single model corresponds to a single Gaussian kernel function. It may be effective for certain kinds of fault but not for others which leads to a poor detection performance. Different Gaussian kernel functions may be needed for each kind of fault. To solve these issue, in this work, a novel ensemble kernel principal component analysis Bayes (EKPCA Bayes) is proposed. The ensemble learning with Bayesian inference strategy were applied into conventional KPCA. At last, the fault diagnosis performance is tested for the first time through contribution plot to find out the root cause variables. The proposed method was tested in the Tennessee Eastman (TE) benchmark process for fault detection and fault diagnosis as well.", "author_names": [ "Xintong Li", "Rui Felizardo", "Feng Xue", "Rui Felizardo Mauaie", "Li-da Qin", "Kai Song" ], "corpus_id": 222221930, "doc_id": "222221930", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fault detection and diagnosis based on new ensemble kernel principal component analysis", "venue": "2019 CAA Symposium on Fault Detection, Supervision and Safety for Technical Processes (SAFEPROCESS)", "year": 2019 }, { "abstract": "Multivariate statistical process monitoring (MSPM) have been applied to process monitoring for industrial processes. The conventional method for a statistical monitoring model is principal component analysis (PCA) However, this is not sufficient to extract meaningful information in non Gaussian data, which is the property of the process data in many industrial processes. Alternatively, the modified independent component analysis (MICA) method can be used to give meaningful information up to higher order statistics, which improves some drawbacks of independent component analysis (ICA) method. In this paper, we propose a protocol to monitor a chatter phenomenon in a hot strip mill process (HSMP) based on modified independent component analysis (MICA) First, we develop the chatter index (CI) that represent the degree of a chatter numerically. The statistical monitoring model for a chatter detection is constructed by using the chatter free data, which is classified by CI. From the chatter monitoring model, a chatter detection rate of 86.7% is achieved.", "author_names": [ "Ha-Nui Jo", "Byeong Eon Park", "Yumi Ji", "Dong-Kuk Kim", "Jeong Eun Yang", "In-Beum Lee", "Jeong Byeol Hong" ], "corpus_id": 210992992, "doc_id": "210992992", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chatter Detection in Hot Strip Mill Process based on Modified Independent Component Analysis", "venue": "2019 IEEE 17th International Conference on Industrial Informatics (INDIN)", "year": 2019 }, { "abstract": "The traditional kernel principal component analysis is popularly used for fault detection, however, it only concentrates on the global structure of data sets and ignores the local structure when it is used to extract the nonlinear features. To solve the problem, a new method named modified kernel principal component analysis is proposed for nonlinear process fault detection and diagnosis. The idea of locality preserving is incorporated into the optimization goal of the traditional kernel principal component analysis, taking the excellence of kernel principal component analysis and manifold learning into account. The new projection space enjoys the similar global structure and the local structure, and thus, more feature information can be extracted. The modified kernel principal component analysis is used to map the data space into the feature space. Next, the feature information is classified through Fisher discriminant analysis. A monitoring statistic is established using the distance of each sample in feature space and its control limit is determined through kernel density estimation. When a fault is detected, the source of performance deterioration can be located by using a diagnosis method based on data set similarity. Finally, the results of Tennessee Eastman simulation experiment show its better effectiveness.", "author_names": [ "Han Mi" ], "corpus_id": 123486057, "doc_id": "123486057", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Fault detection and diagnosis method based on modified kernel principal component analysis", "venue": "", "year": 2015 }, { "abstract": "The traditional FastICA method uses the Newton iteration method which often leads to local minimum solution, so that the suitable independent components are not obtained. To solve this problem, a modified ICA algorithm based on adaptive gradient algorithm (Adam) called Adam ICA is proposed for the purpose of multivariate statistical processes monitoring (MSPM) The basic idea of this algorithm is to extract the main independent components from the original data by adaptive low order moment estimation for fault diagnosis and analysis. The proposed monitoring method is applied to fault detection and diagnosis of the vehicle dataset. The results show that the Adam ICA method is more efficient.", "author_names": [ "Xinxin Shen", "Jianming Zhang" ], "corpus_id": 208280829, "doc_id": "208280829", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fault Detection and Diagnosis Based on Adam ICA", "venue": "2019 IEEE 8th Data Driven Control and Learning Systems Conference (DDCLS)", "year": 2019 } ]

[ { "abstract": "We report a simple, eco friendly facile wet chemical route for the synthesis of pristine and rare earth metal co doped (Er/Yb, 10/90, 15/85, 20/80) nano crystalline, strontium stannate (SrSnO3) whiskers. It is n type wide bandgap ~4.1 eV) orthorhombic perovskite semiconductor at room temperature, and reveals increase in band gap with the increase in Er/Yb content (from 4.10 to 4.23, 4.30 to 4.39 eV) The samples exhibited strong emission around 365 nm following band edge excitation by the wavelength of 290 nm. Further, strong up conversion emission was observed in visible range at the excitation of wavelength 980 nm. The resistivity values were found to decrease with increase in the dopants Er/Yb concentration due to enhancement of charge carriers.", "author_names": [ "Ashok Kumar", "Vikas Sahrawat", "Astakala Anil Kumar", "Shashank Priya" ], "corpus_id": 100576990, "doc_id": "100576990", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Up Conversion in Perovskite Strontium Stannate Nanocrystal Whiskers", "venue": "Transactions of the Indian Institute of Metals", "year": 2017 }, { "abstract": "Much effort has gone into realizing laser cooling with solids over the last two decades. Multiple attempts have been made with systems that include rare earth doped glasses, GaAs heterostructures, CdS nanobelts and hybrid perovskite nanoplatelets. Here we suggest that CsPbBr3 perovskite nanocrystals may eventually lead to verifiable demonstrations of condensed phase laser cooling. The highest emission quantum yield we have realized in CsPbBr3 nanocrystal ensembles is 99.9% at room temperature. This value lies above the critical quantum yield for CsPbBr3, needed to realize laser cooling. We also find that associated CsPbBr3 nanocrystal emission up conversion efficiencies are large and are 75% and 32% for laser detuning energies of 24 meV and 105 meV.", "author_names": [ "Shubin Zhang", "Maksym Zhukovskyi", "Boldizsar Janko", "Masaru Kuno" ], "corpus_id": 139352883, "doc_id": "139352883", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Evaluation of CsPbBr3 nanocrystals for laser cooling", "venue": "OPTO", "year": 2019 }, { "abstract": "As star material, perovskites have been widely used in the fields of optics, photovoltaics, electronics, magnetics, catalysis, sensing, etc. However, some inherent shortcomings, such as low efficiency (power conversion efficiency, external quantum efficiency, etc. and poor stability (against water, oxygen, ultraviolet light, etc. limit their practical applications. Downsizing the materials into nanostructures and incorporating rare earth (RE) ions are effective means to improve their properties and broaden their applications. This review will systematically summarize the key points in the design, synthesis, property improvements and application expansion of RE containing (including both RE based and RE doped) halide and oxide perovskite nanomaterials (PNMs) The critical factors of incorporating RE elements into different perovskite structures and the rational design of functional materials will be discussed in detail. The advantages and disadvantages of different synthesis methods for PNMs will be reviewed. This paper will also summarize some practical experiences in selecting suitable RE elements and designing multi functional materials according to the mechanisms and principles of REs promoting the properties of perovskites. At the end of this review, we will provide an outlook on the opportunities and challenges of RE containing PNMs in various fields.", "author_names": [ "Zhichao Zeng", "Yueshan Xu", "Zheshan Zhang", "Zhansheng Gao", "Meng Luo", "Zongyou Yin", "Chao Zhang", "Jun Xu", "Bolong Huang", "Feng Luo", "Yaping Du", "Chunhua Yan" ], "corpus_id": 210826467, "doc_id": "210826467", "n_citations": 44, "n_key_citations": 0, "score": 0, "title": "Rare earth containing perovskite nanomaterials: design, synthesis, properties and applications.", "venue": "Chemical Society reviews", "year": 2020 }, { "abstract": "The invention relates to a high heat stability nanocrystal rare earth permanent magnet material, belonging to the technical field of magnetic materials. The basic expression of the permanent magnet material is RxFe[100 x y z]ByMz, wherein R is one or more of light rare earth elements neodymium, praseodymium and cerium, Fe is iron, B is boron, and M is one or more of zirconium and hafnium; and x, y and z represent atomic percents, 12<=x<=14.9, 5<=y<=10, and 0.1<=z<=4. The invention also relates to a preparation method of the rare earth permanent magnet material. The high heat stability nanocrystal rare earth permanent magnet material is free of the heavy rare earth element Dy or Tb, has low total rare earth content, and is free of the element Co; and the high heat stability nanocrystal rare earth permanent magnet material has the advantages of low coercivity temperature coefficient, high heat stability and fine and uniform grain size. The preparation process does not need annealing technique treatment, has the advantages of simple technique and lower cost, and thus, is suitable for large scale production.", "author_names": [ "" ], "corpus_id": 103562286, "doc_id": "103562286", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High heat stability nanocrystal rare earth permanent magnet material and preparation method thereof", "venue": "", "year": 2016 }, { "abstract": "Abstract We presented the structural, magnetic, and magnetocaloric data for perovskite TmFeO3. XRD revealed distorted orthorhombic structure (Pbnm) for TmFeO3. Spin reorientation transition was confirmed through magnetic susceptibility. DSM(max) is 13.72 Jkg 1 K 1 at the temperature of 85 K under DH 6 T, with the RCP value of 676 J/kg. DSM(max) and RCP values were increased with the applied field, possibly due to the d f exchange interactions. The magnetic hysteresis cycles are established for different values of temperatures. These properties make it a potential candidate used for magnetic refrigerants. For magnetic refrigeration application, very large refrigeration capacity is also required along with large entropy change value.", "author_names": [ "Poorva Sharma", "Rachid Masrour", "A Jabar", "Jiyu Fan", "Ashwini Kumar", "Langsheng Ling", "Chunlan Ma", "Caixia Wang", "Hao Yang" ], "corpus_id": 213858328, "doc_id": "213858328", "n_citations": 15, "n_key_citations": 0, "score": 1, "title": "Structural and magnetocaloric properties of rare earth orthoferrite perovskite: TmFeO3", "venue": "", "year": 2020 }, { "abstract": "Perovskite manganites exhibit a broad range of structural, electronic, and magnetic properties, which are widely investigated since the discovery of the colossal magnetoresistance effect in 1994. As compared to the parent perovskite manganite oxides, rare earth doped perovskite manganite oxides with a chemical composition of LnxA1 xMnO3 (where Ln represents rare earth metal elements such as La, Pr, Nd, A is divalent alkaline earth metal elements such as Ca, Sr, Ba) exhibit much diverse electrical properties due to that the rare earth doping leads to a change of valence states of manganese which plays a core role in the transport properties. There is not only the technological importance but also the need to understand the fundamental mechanisms behind the unusual magnetic and transport properties that attract enormous attention. Nowadays, with the rapid development of electronic devices toward integration and miniaturization, the feature sizes of the microelectronic devices based on rare earth doped perovskite manganite are down scaled into nanoscale dimensions. At nanoscale, various finite size effects in rare earth doped perovskite manganite oxide nanostructures will lead to more interesting novel properties of this system. In recent years, much progress has been achieved on the rare earth doped perovskite manganite oxide nanostructures after considerable experimental and theoretical efforts. This paper gives an overview of the state of art in the studies on the fabrication, structural characterization, physical properties, and functional applications of rare earth doped perovskite manganite oxide nanostructures. Our review first starts with the short introduction of the research histories and the remarkable discoveries in the rare earth doped perovskite manganites. In the second part, different methods for fabricating rare earth doped perovskite manganite oxide nanostructures are summarized. Next, structural characterization and multifunctional properties of the rare earth doped perovskite manganite oxide nanostructures are in depth reviewed. In the following, potential applications of rare earth doped perovskite manganite oxide nanostructures in the fields of magnetic memory devices and magnetic sensors, spintronic devices, solid oxide fuel cells, magnetic refrigeration, biomedicine, and catalysts are highlighted. Finally, this review concludes with some perspectives and challenges for the future researches of rare earth doped perovskite manganite oxide nanostructures.", "author_names": [ "Weiren Xia", "Zhipeng Pei", "Kai Leng", "Xinhua Zhu" ], "corpus_id": 210166547, "doc_id": "210166547", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Research Progress in Rare Earth Doped Perovskite Manganite Oxide Nanostructures", "venue": "Nanoscale Research Letters", "year": 2020 }, { "abstract": "Piezoelectric materials are technologically important, and the most used are perovskite ferroelectrics. In recent years, more and more emerging areas have put forward new requirements for piezoelectric materials, such as light weight, low acoustic impedance, good flexibility and biocompatibility. In this context, hybrid organic inorganic perovskite ferroelectrics have emerged as promising supplements, because they combine attractive features of inorganic and organic materials. Among them, hybrid double metal perovskites have recently been found to exhibit excellent ferroelectricity. However, their potential as piezoelectric materials hasn't been exploited. Here, we describe large piezoelectric response in hybrid rare earth double perovskite relaxor ferroelectrics (RM3HQ)2RbLa(NO3)6 and (RM3HQ)2NH4La(NO3)6 (RM3HQ R N methyl 3 hydroxylquinuclidinium) They are of the simultaneously ferroelectric and ferroelastic crystals with the R3 ferroelectric phase and P213 paraelectric phase. We found that ferroelectric polar micro domains and paraelectric non polar regions coexist in a wide temperature range through variable temperature piezoresponse force microscopy (PFM) images. The two phase coexist ence reveals low energy barriers of transitions between the two phases and between the polar micro domains with different polarization directions. These lead to the easy polarization rotation of the polar micro domains upon applying a stress, and accordingly, the large piezoelectric response up to 106 pC N 1 for (RM3HQ)2RbLa(NO3)6. This finding represents a significant step toward novel applications of piezoelectric materials based on lead free hybrid perovskites.", "author_names": [ "Chao Shi", "JiaJun Ma", "Jiaying Jiang", "Miao-Miao Hua", "Qi Xu", "Hui Yu", "Yiren Zhang", "Heng-Yun Ye" ], "corpus_id": 216074277, "doc_id": "216074277", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Large Piezoelectric Response in Hybrid Rare Earth Double Perovskite Relaxor Ferroelectrics.", "venue": "Journal of the American Chemical Society", "year": 2020 }, { "abstract": "Abstract Here, we report a comparative study of rare earth doped La0.6R0.1Ca0.3MnO3 (R La, Nd, Sm, Gd, and Dy) samples synthesized by sol gel Pechini process. All the compounds are single phased and crystallize in Pbnm space group with orthorhombic symmetry. Temperature dependent magnetization measurements revealed that all our compounds exhibit a paramagnetic (PM) ferromagnetic (FM) transition with decrease in both ordering temperature TC and the freezing temperature TF with decrease in ionic radii of lanthanide ions. The compounds display metal semiconductor transition and the temperatures (TMS) obtained from the electrical resistivity measurements are consistently higher than those of the Curie temperatures TC. The transport properties are dominated by the Variable range hopping (VRH) model above TMS, showing an increase in characteristic VRH temperature with decreasing size of rare earth ion. The estimated hopping distance (RH) in all the samples is close to nearest neighbor Mn O Mn distance ~5 A) in the ab plane.", "author_names": [ "Nisha Choudhary", "Mukesh kumar Verma", "Narayan Dutt Sharma", "Suman Kumar Sharma", "Devinder Singh" ], "corpus_id": 213590314, "doc_id": "213590314", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Correlation between magnetic and transport properties of rare earth doped perovskite manganites La0.6R0.1Ca0.3MnO3 (R La, Nd, Sm, Gd, and Dy) synthesized by Pechini process", "venue": "", "year": 2020 }, { "abstract": "Perovskite graphene nanocomposites of rare earth LaFeO3 rGO and LaFeO3 nanoparticles are synthesized and characterized. The preparation was done by citrate sol gel method. The structural characterization has been performed using XRD and FT IR. Scanning electron microscope (SEM) and atomic force microscope (AFM) were used to analyze the morphology of the prepared nanocomposite. Vibrating sample magnetometer (VSM) was used to study the magnetic properties of the investigated samples. Introducing graphene to the structure results increase in MS. Also, the optical and thermal properties have been measured and discussed, and the effect of graphene is observed where it decreases the band gap than reported for pure LaFeO3 nanoparticles.", "author_names": [ "Seham K Abdel-Aal", "Ahmed S Abdel-Rahman" ], "corpus_id": 221381848, "doc_id": "221381848", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Graphene influence on the structure, magnetic, and optical properties of rare earth perovskite", "venue": "Journal of Nanoparticle Research", "year": 2020 }, { "abstract": "High entropy oxides (HEO) are a recently introduced class of oxide materials, which are characterized by a large number of elements (i.e. five or more) sharing one lattice site which crystallize in a single phase structure. One complex example of the rather young HEO family are the rare earth transition metal perovskite high entropy oxides. In this comprehensive study, we provide an overview over the magnetic properties of three perovskite type high entropy oxides. The compounds have a rare earth site which is occupied by five different rare earth elements, while the transition metal site is occupied by a single transition metal. In this way a comparison to the parent binary oxides, namely the orthocobaltites, chromites and ferrites is possible. X ray absorption near edge spectroscopy (XANES) magnetometry and M\\\"ossbauer spectroscopy are employed to characterize these complex materials. In general, we find surprising similarities to the magnetic properties of the binary oxides, despite the chemical disorder on the rare earth site. However distinct differences and interesting magnetic properties are also observed such as noncollinearity, spin reorientation transitions as well as large coercive fields of up to 2\\,T at ambient temperature. Both the chemical disorder on the RE A site, and the nature of the TM on the B site play an important role in the physical properties of these high entropy oxides.", "author_names": [ "Ralf Witte", "Abhishek Sarkar", "Leonardo Velasco", "Robert Kruk", "Richard A Brand", "B Eggert", "Katharina Ollefs", "Eugen Weschke", "Heiko Wende", "Horst Hahn" ], "corpus_id": 211010501, "doc_id": "211010501", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Magnetic properties of rare earth and transition metal based perovskite type high entropy oxides", "venue": "", "year": 2020 } ]

[ { "abstract": "Organic inorganic hybrid halide perovskites (OIHPs) are commonly used as prototypical materials for various applications, including photovoltaics, photodetectors, and light emitting devices. Since the chiroptical properties of OIHPs are deciphered in 2017, chiral OIHPs have been rediscovered as new hybrid systems comprising chiral organic molecules and achiral inorganic octahedral layers. Owing to their exceptional optoelectrical properties and structural flexibility, chiral OIHPs have received a considerable amount of attention in chiral photonics, chiroptoelectronics, spintronics, and ferroelectrics. Despite their intriguing chiral properties, the transfer mechanism from chiral molecules to achiral semiconductors has not been extensively investigated. Furthermore, an in depth understanding of the origin of chiroptical activity is still elusive. In this review article, recent advances in the chiroptical activities of chiral OIHPs and polarization based devices adopting chiral OIHPs are comprehensively discussed, and insight into the underlying chirality transfer mechanism based on theoretical considerations is provided. This comprehensive survey, with an emphasis on the chirality transfer mechanism, will help readers understand the chiroptical properties of OIHPs, which are crucial for the development of spin based photonic and optoelectronic devices. Additionally, promising strategies to exploit the potential of chiral OIHPs are also discussed.", "author_names": [ "Sunihl Ma", "Jihoon Ahn", "Jooho Moon" ], "corpus_id": 233350720, "doc_id": "233350720", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Chiral Perovskites for Next Generation Photonics: From Chirality Transfer to Chiroptical Activity.", "venue": "Advanced materials", "year": 2021 }, { "abstract": "Two dimensional (2D) hybrid halide perovskites with single chiral and ferroelectricity together with various structural phase transitions provide the possibility for them to have more diverse functional properties. Here, we present a 2D chiral hybrid halide perovskite ferroelectric, [C 6 H 5 (CH 2 4 NH 3 2 CdCl 4 4PBA CdCl 4 4PBA 4 Phenylbutylamine) which experiences two continuous phase transitions from centrosymmetric triclinic P to polar chiral monoclinic P 2 and then to another centrosymmetric tetragonal P 4 /mmm with increasing temperature, accompanied by symmetry breaking, due to the prominent octahedral distortion and disorder transformation of organic 4PBA cations. Under polar chiral phase, 4PBA CdCl 4 exhibits a significant CD signal and a moderate ferroelectric polarization of 0.35 mC/cm 2 In addition, 4PBA CdCl 4 occupies a wide band gap of 4.376 eV and is chiefly contributed by inorganic CdCl 6 octahedron. This finding offers an alternative pathway for designing new phase transitions and related physical properties in hybrid halide perovskites and other hybrid crystals.", "author_names": [ "Lin Sui Li", "Wen Juan Wei", "Hong Qiang Gao", "Yu Hui Tan", "Xiao Bo Han" ], "corpus_id": 233222239, "doc_id": "233222239", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Molecular Disorder Induces Unusual Phase Transition in a Potential 2D Chiral Ferroelectric Perovskite.", "venue": "Chemistry", "year": 2021 }, { "abstract": "The control of the optoelectronic properties of 2D organic inorganic hybrid perovskite (2D OIHP) lead halides is an increasingly prevalent topic. Herein, the observation of the circular photogalvanic effect (CPGE) in new enantiomorphic 2D OIHP lead iodides is reported, which are synthesized as a first OIHP related system belonging to a chiral space group by incorporating organic chiral cations into the inorganic layers of lead iodides. The CPGE is an optoelectronic phenomenon associated with the spin orbit coupling of heavy atoms in noncentrosymmetric systems. Owing to the CPGE, light helicity dependent steady photocurrents are generated without an external bias voltage under the irradiation of circularly polarized light. Furthermore, the sign reversal of the CPGE photocurrent depending on the chirality of the designed 2D OIHP lead iodides is observed. This result indicates formation of the theoretically predicted radial spin polarized texture in k space of chiral systems owing to spin momentum locking. Hence, chiral 2D OIHP lead halides can be a promising platform for engineering opto spintronic functionalities.", "author_names": [ "Po-Jung Huang", "Kouji Taniguchi", "Masato Shigefuji", "Takatsugu Kobayashi", "Masakazu Matsubara", "Takao Sasagawa", "Hiroyasu Sato", "Hitoshi Miyasaka" ], "corpus_id": 232325989, "doc_id": "232325989", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Chirality Dependent Circular Photogalvanic Effect in Enantiomorphic 2D Organic Inorganic Hybrid Perovskites.", "venue": "Advanced materials", "year": 2021 }, { "abstract": "Chiral perovskites with circularly polarized luminescence (CPL) performance have attracted tremendous attention. This contribution reports a convenient and universal strategy for constructing chiral helical polymer/perovskite hybrid nanofibers with outstanding CPL properties. The hybrid nanofibers are prepared through a one step electrospinning method in which chiral helical polyacetylenes, perovskite nanocrystals, and polyacrylonitrile serve as a handed selective fluorescence filter, fluorescent source, and electrospinning matrix, respectively. Specially, perovskite nanocrystals are in situ formed during the electrospinning process, which avoids the tedious process for preparing and purifying perovskites. The prepared hybrid nanofibers all exhibit good long time stability in air, owing to the effective protection effect of polymer matrix. More importantly, intense CPL emissions with high dissymmetry factor up to 10 2 level are obtained in the hybrid nanofibers. Furthermore, the emission color of CPL can be easily tuned by adjusting the precursors of perovskites. This work provides an efficient technique toward various kinds of CPL active perovskite nanomaterials for both scientific research and future practical applications.", "author_names": [ "Biao Zhao", "Kai Pan", "Jianping Deng" ], "corpus_id": 232242345, "doc_id": "232242345", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Chiral Helical Polymer/Perovskite Hybrid Nanofibers with Intense Circularly Polarized Luminescence.", "venue": "ACS nano", "year": 2021 }, { "abstract": "Spin injection sans magnetism Light emitting diodes (LEDs) that emit circularly polarized light (spin LEDs) have potential applications in in three dimensional displays, bioencoding, and tomography. The requisite spin polarization of the charge carriers is usually achieved with ferromagnetic contacts and applied magnetic fields, but Kim et al. report on a room temperature spin LED that relies instead on a chiral induced spin selectivity organic layer. This layer selectively injected spin polarized holes into metal halide perovskite nanocrystals, where they radiatively recombined with unpolarized electrons with an efficiency of 2.6% Science, this issue p. 1129 Spin polarized light emitting diodes based on metal halide perovskites operate at room temperature without a magnetic field. In traditional optoelectronic approaches, control over spin, charge, and light requires the use of both electrical and magnetic fields. In a spin polarized light emitting diode (spin LED) charges are injected, and circularly polarized light is emitted from spin polarized carrier pairs. Typically, the injection of carriers occurs with the application of an electric field, whereas spin polarization can be achieved using an applied magnetic field or polarized ferromagnetic contacts. We used chiral induced spin selectivity (CISS) to produce spin polarized carriers and demonstrate a spin LED that operates at room temperature without magnetic fields or ferromagnetic contacts. The CISS layer consists of oriented, self assembled small chiral molecules within a layered organic inorganic metal halide hybrid semiconductor framework. The spin LED achieves 2.6% circularly polarized electroluminescence at room temperature.", "author_names": [ "Young-Hoon Kim", "Yaxin Zhai", "Haipeng Lu", "Xin Pan", "Chuanxiao Xiao", "E Ashley Gaulding", "Steven P Harvey", "Joseph J Berry", "Zeev Valy Vardeny", "Joseph M Luther", "Matthew C Beard" ], "corpus_id": 232199799, "doc_id": "232199799", "n_citations": 18, "n_key_citations": 0, "score": 1, "title": "Chiral induced spin selectivity enables a room temperature spin light emitting diode", "venue": "Science", "year": 2021 }, { "abstract": "Chiral perovskite materials have been intensively studied because of their unique properties and wide range of potential applications; however, the synthesis of perovskite nanocrystals with improved chirality has been scarcely investigated. In this Letter, two dimensional perovskite nanosheets with intrinsic chirality are demonstrated. Inserting chiral amines into the perovskite framework leads to the chirality transfer from amine molecules to perovskite structure. The protecting agent, specifically, achiral octylamine, is found to influence the chiral optical signal or dissymmetric factor of nanosheets significantly. By controlling the amount of octylamine, we have synthesized perovskite nanosheets with the highest g factor ever reported. We expect our primary demonstration could attract more attention toward the synthesis of intrinsic chiral perovskite nanocrystals and the development of nanocrystal based chiral optical devices with improved functions.", "author_names": [ "He Ren", "Yue Wu", "Chenchen Wang", "Yong Yan" ], "corpus_id": 232193404, "doc_id": "232193404", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "2D Perovskite Nanosheets with Intrinsic Chirality.", "venue": "The journal of physical chemistry letters", "year": 2021 }, { "abstract": "The layered perovskite YBaCuFeO5 (YBCFO) is considered one of the best candidates to high temperature chiral multiferroics with strong magnetoelectric coupling. In RBaCuFeO5 perovskites (R: rare earth or Y) A site cations are fully ordered whereas their magnetic properties strongly depend on the preparation process. They exhibit partial cationic disorder at the B site that generates a magnetic spiral stabilized through directionally assisted long range coupling between canted locally frustrated spins. Moreover the orientation of its magnetic spiral can be critical for the magnetoelectric response of this chiral magnetic oxide. We have synthesized and studied YBaCuFe1 xMnxO5 samples doped with Mn, with the aim of increasing spin orbit coupling effects, and found that the overall Fe/Cu cation disorder at the B sites can be increased by doping without changing the sample preparation process. In YBaCuFe1 xMnxO5 samples prepared under the same conditions, the T x magnetic phase diagram have been constructed in the range 10K 500K combining magnetometry, X ray and neutron powder diffraction measurements. The tilting angles of the spins in the collinear, \\theta}col and spiral phases, \\theta}spiral, barely vary with temperature. In the collinear phase \\theta}col is also independent of the Mn content. In contrast, the presence of Mn produces a progressive reorientation of the plane of the magnetic helix in the incommensurate phase, capable to transform the helicoidal spin ordering into a cycloidal one, which may critically determine the ferroelectric and magnetoelectric behavior in these compounds. Some of the observations are of interest for engineering and developing this family of potential high temperature multiferroics.", "author_names": [ "Arnau Romaguera", "Oscar Fabelo", "Francois Fauth", "Javier Herrero-Martin", "Jose Luis Garcia-Munoz" ], "corpus_id": 232168645, "doc_id": "232168645", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Tuning the tilting of the spiral plane by Mn doping in YBaCuFeO5 multiferroic", "venue": "", "year": 2021 }, { "abstract": "Chiral perovskites have emerged as a significant class of materials showing promising optoelectronic and spintronic applications. Reports of chiral perovskite ferroelectrics, however, have been scarce. In this work, we have successfully synthesized homochiral lead iodide perovskite ferroelectrics (R) N (1 phenylethyl)ethane 1,2 diaminium]PbI4 and (S) N (1 phenylethyl)ethane 1,2 diaminium]PbI4 by the chemical design of introducing a methyl group into the organic cation of the parent (N benzylethane 1,2 diaminium)PbI4. Vibrational circular dichroism spectra identify the chiral mirroring relationship. They both undergo 222F2 type paraelectric ferroelectric behavior at around 378 K coupled with clear ferroelastic domains \"ON/OFF\" switching. Besides, they exhibit an evident thermochromism with color change from orange yellow to orange red. To our knowledge, the discovery of integrated ferroelectricity, ferroelasticity and reversible thermochromism in chiral perovskites is unprecedented. This finding offers a resultful path to design chiral perovskite ferroelectrics and is of great inspiration to the discovery of multifunctional perovskite materials.", "author_names": [ "Yu-Ling Zeng", "Xue-Qin Huang", "Chao-Ran Huang", "Hua Zhang", "Fang Wang", "Zhongxia Wang" ], "corpus_id": 232078164, "doc_id": "232078164", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Unprecedented 2D Homochiral Hybrid Lead Iodide Perovskite Thermochromic Ferroelectrics with Ferroelastic Switching.", "venue": "Angewandte Chemie", "year": 2021 }, { "abstract": "Low dimensional hybrid organic inorganic perovskites (HOIPs) possess more localized electronic states and narrower conduction and valence bands to promote self trapping of excitons and stronger exciton emission; therefore, they are widely used as building blocks for various applications in the fields of optoelectronics, photovoltaics, light emitting diodes, luminescence, fluorescence, and so forth. Despite the past decades of intensive study, the discovered low dimensional chiral HOIPs are rare as of the 1D chiral HOIP single crystals reported in 2003, as well as the low dimensional chiral HOIP ferroelectrics are particularly scarce since the first chiral two dimensional (2D) and/or one dimensional (1D) HOIP ferroelectrics reported. Herein, two new low dimensional HOIPs with the same conformational formula [R MPA]2CdCl4 (R MPA+ (R) 1 methyl 3 phenylpropylamine) were successfully synthetized by means of regulating the stoichiometric proportion of R MPA and CdCl2 in two ways of 1:1 (1) and 2:1 (2) By combining single crystal X ray diffraction, circular dichroism (CD) spectroscopy, differential scanning calorimetry, temperature dependent dielectric constant, temperature dependent second harmonic generation (SHG) effect, polarization dependent SHG response, and P E hysteresis loop, we reveal that 1 is a 1D nonchiral molecular ferroelectric and 2 is the first zero dimensional (0D) chiral ferroelectric with distinct CD signals; meanwhile, 2 exhibits increased properties of high Tc, large dielectric constant, SHG isotropy, and ferroelectricity than that of 1. These results not only shed light on the high tunability of the low dimensional HOIP ferroelectrics but also open up an avenue to explore multifunctional chiral ferroelectrics.", "author_names": [ "Lin-Sui Li", "Yu-Hui Tan", "Wen-Juan Wei", "Hongqiang Gao", "Yun-Zhi Tang", "Xiao-Bo Han" ], "corpus_id": 229353701, "doc_id": "229353701", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Chiral Switchable Low Dimensional Perovskite Ferroelectrics.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "Metal halide perovskites are recently emerging as the promising alternative for CPL detection owing to their CPL sensitive property induced by chiral organics and efficient charge transport of inorganic frameworks. However, most of these reported chiral perovskites involve high concentrations of toxic Pb which will become the potential bottleneck for their further application. Herein, we successfully developed two lead free halide double perovskites, R b MPA] 4 AgBiI 8 R b MPA R b methylphenethylammonium, 1 R and S b MPA] 4 AgBiI 8 S b MPA S b methylphenethylammonium, 1 S Circular dichroism measurements reveal that these perovskites exhibit notable chirality induced by organic cations to distinguish different polarization states of CPL photons. Significantly, they present unique chiral polar photovoltaic, and resulting self powered CPL detection without an external power source is unprecedentedly achieved. Furthermore, an anisotropy factor up to 0.3 is acquired for the self powered CPL detection, reaching the highest value among reported chiral perovskites. This work suggests hybrid double perovskites are promising photoelectronic candidates, and provides a new approach for exploring new \"green\" circularly polarized light sensitive materials with high perfromance", "author_names": [ "Dong Li", "Xitao Liu", "Wentao Wu", "Yunyan Peng", "Sangen Zhao", "Lina Li", "Maochun Hong", "Junhua Luo" ], "corpus_id": 229351622, "doc_id": "229351622", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Chiral lead free hybrid perovskites for self powered circularly polarized light detection.", "venue": "Angewandte Chemie", "year": 2020 } ]

[ { "abstract": "The interface between photoactive biological materials with two distinct semiconducting electrodes is challenging both to develop and analyze. Building off of our previous work using films of photosystem I (PSI) on p doped silicon, we have deposited a crystalline zinc oxide (ZnO) anode using confined plume chemical deposition (CPCD) We demonstrate the ability of CPCD to deposit crystalline ZnO without damage to the PSI biomaterial. Using electrochemical techniques, we were able to probe this complex semiconductor biological interface. Finally, as a proof of concept, a solid state photovoltaic device consisting of p doped silicon, PSI, ZnO, and ITO was constructed and evaluated.", "author_names": [ "Jeremiah C Beam", "Gabriel LeBlanc", "Evan A Gizzie", "Borislav L Ivanov", "David R Needell", "Melinda J Shearer", "G Kane Jennings", "Charles M Lukehart", "David E Cliffel" ], "corpus_id": 8512199, "doc_id": "8512199", "n_citations": 15, "n_key_citations": 2, "score": 0, "title": "Construction of a Semiconductor Biological Interface for Solar Energy Conversion: p Doped Silicon/Photosystem I/Zinc Oxide.", "venue": "Langmuir the ACS journal of surfaces and colloids", "year": 2015 }, { "abstract": "Morphological and optical characteristics of radio frequency sputtered zinc aluminum oxide over porous silicon (PS) substrates were studied before and after irradiating composite films with 130 MeV of nickel ions at different fluences varying from 1 x 1012 to 3 x 1013 ions/cm2. The effect of irradiation on the composite structure was investigated by scanning electron microscopy, X ray diffraction (XRD) photoluminescence (PL) and cathodoluminescence spectroscopy. Current voltage characteristics of ZnO PS heterojunctions were also measured. As compared to the granular crystallites of zinc oxide layer, Al doped zinc oxide (ZnO) layer showed a flaky structure. The PL spectrum of the pristine composite structure consists of the emission from the ZnO layer as well as the near infrared emission from the PS substrate. Due to an increase in the number of deep level defects, possibly oxygen vacancies after swift ion irradiation, PS Al doped ZnO nanocomposites formed with high porosity PS are shown to demonstrate a broadening in the PL emission band, leading to the white light emission. The broadening effect is found to increase with an increase in the ion fluence and porosity. XRD study revealed the relative resistance of the film against the irradiation, i.e. the irradiation of the structure failed to completely amorphize the structure, suggesting its possible application in optoelectronics and sensing applications under harsh radiation conditions.", "author_names": [ "Yogesh Kumar", "Manuel Herrera-Zaldivar", "Sion Federico Olive-Mendez", "Fouran Singh", "Xavier Mathew", "Vivechana Agarwal" ], "corpus_id": 10874422, "doc_id": "10874422", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "Modification of optical and electrical properties of zinc oxide coated porous silicon nanostructures induced by swift heavy ion", "venue": "Nanoscale Research Letters", "year": 2012 }, { "abstract": "Abstract An in situ calcination strategy has been developed for the synthesis of porous zinc oxide/N doped carbon (ZnO/NC) polyhedrons, in which zeolitic imidazolate framework 8 (ZIF 8) serves as the precursor. The ZnO/NC polyhedrons with a hierarchical architecture possess a high specific surface area of 390.7 m 2 g 1 high nitrogen content (19.99 at% and robust pore structures. The porous N doped carbon frameworks can not only increase the electronic conductivity of ZnO, but also provide interior space for the fast diffusion of Li ions and accommodate the volume variations during the charge and discharge cycles. When evaluated for lithium storage capacity, the hierarchical ZnO/NC polyhedrons exhibit high reversible discharge capacity (834.3 mAh g 1 at the initial low rate of 0.5C, 1C 978 mA g 1 superior rate performance (399.2 mAh g 1 at 5C and 253.5 mAh g 1 at 10C) and excellent cycling stability (677.9 mAh g 1 at 1C after 400 cycles) The reasons are explored in terms of the well confined primary nanocrystals (5 nm) and the finely constructed interconnected pores of the N doped carbon networks, which facilitate the fast and effective transfer of Li ions and electrons, and accommodate the large volume expansions.", "author_names": [ "Zhenfang Zhou", "Kun Zhang", "Jinghao Liu", "Hongrui Peng", "Guicun Li" ], "corpus_id": 95860735, "doc_id": "95860735", "n_citations": 43, "n_key_citations": 1, "score": 0, "title": "Comparison study of electrochemical properties of porous zinc oxide/N doped carbon and pristine zinc oxide polyhedrons", "venue": "", "year": 2015 }, { "abstract": "Abstract We report the room temperature cathodoluminescence and photoluminescence of swift ion irradiated (130 MeV Nickel ion) porous silicon zinc oxide nanocomposites. The evolution of a broad and flat emission band from 1.5 to 3.5 eV is demonstrated. Annealing effect of irradiation is found to result in a relative increase in the band edge emission. Emission wavelength can be tuned in the complete visible range by changing the substrate characteristics.", "author_names": [ "Yogesh Kumar", "M Herrera", "Fouran Singh", "Sion Federico Olive-Mendez", "Dinakar Kanjilal", "Shiv Kumar", "Vivechana Agarwal" ], "corpus_id": 96148307, "doc_id": "96148307", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Cathodoluminescence and photoluminescence of swift ion irradiation modified zinc oxide porous silicon nanocomposite", "venue": "", "year": 2012 }, { "abstract": "Sol gel grown polycrystalline Al doped zinc oxide (AZO) thin films have been deposited on Si wafers, microscopy slide glass and fluorine doped tin oxide coated glass substrates using the spin coating technique. The atomic ratio of Al:Zn in the films is 0.2. From the X ray diffraction investigations it is found that the preferential growth of (100) reflection peak has taken place in the 450, 550 and 600 degC annealed films. Scanning electron microscopic study has shown that the films contain well defined grains arranged in a closely packed array. The resistivity of the 500 degC annealed film is measured to be 5 x 10 1 O cm. The films have exhibited excellent optical transmittance 90% in the 400 1100 nm wavelength range. Refractive indices (n 1.9 1.95) of the films on Si wafer are independent of the annealing temperature. Thickness of the films produced at 4000 rpm is in the range of 58 62 nm. The refractive index and thickness of these films are nearly appropriate to cause destructive interference after reflection from front emitters of solar cells. These films have demonstrated a reflectivity value of about 3% at a wavelength of 700 nm. The AZO coated silicon solar cells possess Voc and Isc values of 573 mV and 237 mA, respectively.", "author_names": [ "Amitabh Verma", "Firoz Shah Tuglak Khan", "Dinesh Kumar", "M Kar", "B C Chakravarty", "Sukhvir Singh", "Mushahid Husain" ], "corpus_id": 96254040, "doc_id": "96254040", "n_citations": 77, "n_key_citations": 1, "score": 0, "title": "Sol gel derived aluminum doped zinc oxide for application as anti reflection coating in terrestrial silicon solar cells", "venue": "", "year": 2010 }, { "abstract": "Abstract Aerogel nanopowder of calcium doped zinc oxide (ZnO:Ca) was synthesized by modified sol gel method. In this process, hydrolyses was slowly released and followed by a thermal drying in supercritical conditions or ethyl alcohol. The obtained nanopowder was characterized by various techniques such as X ray diffraction (XRD) scanning electron microscopy (SEM) transmission electron microscopy (TEM) Cathodoluminescence (CL) and photoluminescence (PL) XRD data showed that Ca doped ZnO sample has a hexagonal wurtzite structure with a slight distortion of ZnO lattice and no extra secondary phases, suggesting the substitution of Ca ions in the ZnO structure. SEM micrograph shows spherical microparticles having a rough porous fine grained. From TEM micrograph, the samples are composed by single particles having an inhomogeneous size distribution, with most of them having a dimension in the range between 20 and 50 nm. This powder presents a strong photoluminescence band in the visible range. From photoluminescence excitation (PLE) the energy position of the obtained PL band depends on the wavelength of excitation. The luminescence results are also confirmed by cathodoluminescence technique and suggests the presence of photo active centers in ZnO:Ca as deduced from new published works for visible photo activated gas sensors and photo catalysis of dyes degradation. We hope that this work provides some answers to the scientific community concerning the effect of doping in the creation of optical active centers in ZnO, promising for many technological applications.", "author_names": [ "Lassaad El Mir" ], "corpus_id": 99735419, "doc_id": "99735419", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Luminescence properties of calcium doped zinc oxide nanoparticles", "venue": "", "year": 2017 }, { "abstract": "We report the obtaining of electroluminescent devices (ELD) from porous silicon (PS) and indium doped zinc oxide (ZnO:In) junctions. PS presented photoluminescence (PL) in the visible region of the electromagnetic spectrum. ZnO:In thin film was obtained by dip coating technique. SEM images and IR measurements showed the incorporation of the ZnO:In in the PS structure. Once obtained, the device was optically and electrically characterized. The ELD showed emission in the visible (450 850 nm) and infrared region (900 1200 nm) where it was electrically polarized. The visible emission was detected as luminescent spots on the surface. Electrical characterization was carried out by current voltage (I V) curves. The I V curves showed rectifying behavior. It was related to the quenching of the EL with the process that takes place in the PS when it was immersed in the precursor solution of the ZnO:In.", "author_names": [ "F Severiano", "Godofredo Garcia", "Luis Castaneda", "V Lopez Gayou" ], "corpus_id": 55049390, "doc_id": "55049390", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Porous Silicon and Indium Doped Zinc Oxide Junctions: Synthesis, Characterization, and Application to Electroluminescent Devices", "venue": "", "year": 2017 }, { "abstract": "The luminescent properties of zinc oxide (ZnO) and nanostructured porous silicon (PSi) make these materials very appealing for photoemission applications. The current study reports on the fabrication of a composite of ZnO and nanostructured porous silicon micropatterns (ZnO PSi micropatterns) onto heavily doped silicon surfaces. The proposed composite micropattern is devoted to the future development of light emitting diodes. The fabrication of the ZnO PSi micropatterns was carried out in a two step process. (1) A regular hexagonal micropattern of a photoresist/ZnO stack was fabricated by UV lithography on crystalline silicon substrates. (2) Before being lifted off the photoresist, nanostructured PSi micropatterns were fabricated by electrochemically etching the exposed areas of the silicon substrate. Subsequently, wet etching of the photoresist was carried out for the final development of the composite ZnO and PSi micropatterns. Further, thin films of ZnO and nanostructured PSi layers were characterized. In particular, their photoluminescent properties were analyzed, as well as their morphology and composition. The experimental PL results show that the ZnO layers have emission broadbands centered at (2.63 eV, blue) while the PSi layers show a band centered at (1.71 eV, red) Further, the emission peaks from the PSi layers can be tuned by changing their fabrication conditions. It was observed that the properties of the ZnO thin films are not influenced by either the surface morphology of PSi or by its PL emissions. Therefore, the PL properties of the composite ZnO PSi micropatterns are equivalent to those featuring the addition of PSi layers and ZnO thin films. Accordingly, broadband optical emissions are expected to arise from a combination between the ZnO layer (blue band) and PSi (red band) Furthermore, the electrical losses associated with the PSi areas can be greatly reduced since ZnO is in contact with the Si surface. As a result, the proposed composite micropatterns might be attractive for many solid state lighting applications, such as light emitting diodes.", "author_names": [ "Rehab Ramadan", "Vicente Torres-Costa", "Raul Jose Martin-Palma" ], "corpus_id": 219753111, "doc_id": "219753111", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Fabrication of Zinc Oxide and Nanostructured Porous Silicon Composite Micropatterns on Silicon", "venue": "", "year": 2020 }, { "abstract": "Electroluminescent devices (ELD) based on junctions of indium doped zinc oxide (ZnO:In) and porous silicon layers (PSL) are presented in this work. PSL with different thicknesses and photoluminescent emission, around 680 nm, were obtained by anodic etching. PSL were coated with a ZnO:In film which was obtained by ultrasonic spray pyrolysis technique. Once obtained, this structure was optically and electrically characterized. When the devices were electrically polarized they showed stable electroluminescence (EL) which was presented as dots scattered over the surface. These dots can be seen with the naked eye. The observed EL goes from the 410 to 1100 nm, which is formed by different emission bands. The EL emission in the visible region was around 400 to 750 nm, and the emission corresponding to the infrared part covers the 750 to 1150 nm. The electrical characterization was carried out by current voltage curves (I V) which show a rectifying behavior of the devices. Observed electroluminescent dots are associated with the electron hole injection into quantized states in PS as well as the emission from the ZnO:In film.", "author_names": [ "F Severiano", "Godofredo Garcia", "Luis Castaneda", "J M Gracia-Jimenez", "Heberto Gomez-Pozos", "Jose Alberto Luna-Lopez" ], "corpus_id": 55134912, "doc_id": "55134912", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Electroluminescent devices based on junctions of indium doped zinc oxide and porous silicon", "venue": "", "year": 2014 }, { "abstract": "Abstract In this study we obtained electroluminescent devices (ELD) based on junctions of indium doped zinc oxide (ZnO:In) and porous silicon layers (PSL) The PSL were obtained by electrochemical etching with different types and resistivities of silicon wafers. In the visible part of the electromagnetic spectrum, the porous silicon (PS) exhibits photoluminescence (PL) that is centered around 680 nm. Once the devices were obtained, they were optically and electrically characterized. The PSL were coated with ZnO:In film, which was gotten by the ultrasonic spray pyrolysis technique (USP) When the devices were electrically polarized they showed optical response in the regions corresponding to the visible and infrared band of the electromagnetic spectrum. The observed electroluminescence (EL) in the visible region goes from 400 to 750 nm and the corresponding emission of the infrared part is around 750 1150 nm. The devices presented luminescent spots on the surface which were visible to the naked eye. The analysis of the results shows that the emission source in the visible part is attributed to the filaments present in the PS, and also to the ZnO:In films and the emission in the infrared part is associated to the silicon substrate. The electrical characterization was carried out by current voltage curves I V that show in the devices a rectifying behavior.", "author_names": [ "F Severiano", "Godofredo Garcia", "Luis Castaneda" ], "corpus_id": 94952007, "doc_id": "94952007", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Study of the electroluminescent properties of crystalline silicon wafers in devices based on junctions of indium doped zinc oxide and porous silicon", "venue": "", "year": 2014 } ]

[ { "abstract": "Wafer map defect pattern contains the critical information about semiconductor manufacturing, effective defect analysis technology can improve the yield of products. This paper develops a wafer defect pattern recognition and analysis method based on convolutional neural network (CNN) We build an 8 layer CNN model to inspect wafer map defect and a 13 layer model to classify defect patterns. To analyze the defects, we first extract features based on the classification network, then perform PCA dimensionality reduction and similarity ranking, we infer the root causes of tested samples according to the retrieved wafer maps. In particular, we analyze the impacts of different network layers and feature dimensions on image retrieval performance, it turns out that the appropriate dimensionality reduction can increase the accuracy and speed of wafer map retrieval. The models are trained and tested on the WM 811K wafer map dataset, which are collected from real wafer maps. The experimental results show that the proposed method is able to identify common wafer defect patterns and analyze the root causes accurately and effectively.", "author_names": [ "Naigong Yu", "Qiao Xu", "Honglu Wang" ], "corpus_id": 203005832, "doc_id": "203005832", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "Wafer Defect Pattern Recognition and Analysis Based on Convolutional Neural Network", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2019 }, { "abstract": "A robotic cluster tool involves many activities whose time is subject to some disturbance, thus leading to the activity time variation. It results in wafer sojourn time fluctuation in a process module, which may in turn violate wafer residency time constraints. Some wafer fabrication requires a revisiting process. With wafer revisiting, the effect of activity time variation on wafer sojourn time fluctuation is so complicated that no analysis was reported to the best knowledge of the authors. It is vitally important to accurately analyze it. To do so, this paper adopts a Petri net model to describe the dynamical behavior of cluster tools. With this model, a real time control policy is proposed to offset the effect of the activity time variation on wafer sojourn time fluctuation as much as possible. Then, the wafer sojourn time delay is analyzed and algorithms are developed to calculate its exact upper bound. With the proposed method, one can check if a given schedule is feasible under bounded activity time variation. Some practical examples are given to show the application of the proposed approach.", "author_names": [ "Yan Qiao", "Naiqi Wu", "Fajun Yang", "Mengchu Zhou", "Qinghua Zhu" ], "corpus_id": 3900345, "doc_id": "3900345", "n_citations": 50, "n_key_citations": 1, "score": 0, "title": "Wafer Sojourn Time Fluctuation Analysis of Time Constrained Dual Arm Cluster Tools With Wafer Revisiting and Activity Time Variation", "venue": "IEEE Transactions on Systems, Man, and Cybernetics: Systems", "year": 2018 }, { "abstract": "This paper investigates on wafer characterization of SiGe HBTs up to 500 GHz. Test structures for on wafer thru reflect line (TRL) calibration have been designed and are presented. The TRL calibration method with silicon standards has first been benchmarked through electromagnetic simulation. Passive and active components are then characterized up to 500 GHz. The slight discontinuities between the frequency bands are explored. A specific focus was placed on incorrect horizontal probe positioning as well as on probe deformation, resulting in a better assessment of possible measurement errors.", "author_names": [ "Sebastien Fregonese", "Magali De matos", "Marina Deng", "Manuel Potereau", "Cedric Ayela", "Klaus Aufinger", "Thomas Zimmer" ], "corpus_id": 49556354, "doc_id": "49556354", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "On Wafer Characterization of Silicon Transistors Up To 500 GHz and Analysis of Measurement Discontinuities Between the Frequency Bands", "venue": "IEEE Transactions on Microwave Theory and Techniques", "year": 2018 }, { "abstract": "Recently, Wafer Level Packaging (WLP) has been in high demand, especially in mobile device applications as a path to enable miniaturization while maintaining good electrical performance. The relatively inexpensive package cost and simplified supply chain are encouraging other industries to adapt WLP capabilities for radio frequency (RF) communications/sensing (mmWave) and automotive applications. However, to date its application space has been limited to a small die form factor due to challenging chip board interaction (CBI) control. The combination of ultralow dielectric constant (ULK) based advanced silicon technology and WLP is another challenge for industry to overcome.In this article, to systematically address the CBI, a large test vehicle based on 22 nm fully depleted silicon on insulator (FD SOI) technology platform and WLP technology is described. In particular, CBI during drop test and temperature cycle on board is investigated and its failure mode analysis is discussed. The impact of silicon die thickness and ball grid array (BGA) metallurgy is also explored.", "author_names": [ "Jae Kyu Cho", "Jens Paul", "Simone Capecchi", "Dirk Breuer", "Frank Kuechenmeister", "Doug Scott", "Jong-Gyu Choi", "Wonjoon Kang" ], "corpus_id": 56171289, "doc_id": "56171289", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Chip Board Interaction Analysis of 22 NM Fully Depeleted Silicon on Insulator (FD SOI) Technology in Wafer Level Packaging (WLP)", "venue": "2018 International Wafer Level Packaging Conference (IWLPC)", "year": 2018 }, { "abstract": "In modern foundry industry, capacity and yield are the two very important indicators to show how good the foundry is. In the past decades, the size of silicon wafer has been increased from 100nm to current 300nm, so that more dies can be packed the wafer. However, due to process constrains and increasing in the wafer dimension, the yield loss on wafer edge becomes more severe. Failure analysis acts as a powerful tool to help Fab in identifying the root cause of the wafer edge failure. In this paper, several wafer edge cases caused by different process modules were presented. The FA findings provided the evidence to show how the process uniformity limitation can cause the failure on wafer edge. Hence, Fab can take the corresponding actions to solve the issue, also continuously process tuning activities can be carried out, hence the yield loss on wafer edge can be reduced.", "author_names": [ "N Y Xu", "HP Ng", "G B Ang", "C Q Chen", "Angela Teo", "Andrew Jerome", "Y S Tam", "Yajing Li", "Zhihong Mai" ], "corpus_id": 52166711, "doc_id": "52166711", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Failure Analysis Case Studies on Wafer Edge Failure due to Process Uniformity Issue", "venue": "2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA)", "year": 2018 }, { "abstract": "In this paper, a low yield case relating to IDD leakage at active mode due to the systematic breakdown signature consistently at the top MIM edge was studied. The systematic problem solving process based on the application of a variety of FA techniques such as TIVA, AFP probing, layout path tracing, FIB circuit edit, SEM XTEM and top down PFA methodology together with Fab investigation are used to understand the root cause as well as failure mechanism. This paper highlights that there are 2 types of leakage (high leakage in mA and low leakage in uA) The high leakage dies revealed spot directly at the MIM cap and anomaly can be observed at the MIM edge. However, for the low level leakage, hotspot was seen at the PMOS transistor and NOT at the MIM Cap. Besides layout tracing that enable to pinpoint the suspected MIM cap, 2 types of simulation (Intentionally induced damage and FIB Circuit Edit) were performed to prove and validate the MIM defect is the only root cause for this low yield issue and the RF circuitry has no contribution to it. Additionally, top down PFA methodology was engaged to reveal the physical evidence of the damage at the edge of the MIM. This confirmed that both type of leakage are due to similar MIM breakdown issue.", "author_names": [ "Angela Teo", "Ang Ghim Boon", "Ng Hui Peng", "Chen Chang Qing", "Xu Nai Yun", "N Dayanand", "Tam Yong Seng", "Mai Zhi Hong", "Jeffrey Lam" ], "corpus_id": 52158900, "doc_id": "52158900", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Failure Analysis Methodology on Systematic MIM failure in Wafer Fabrication", "venue": "2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA)", "year": 2018 }, { "abstract": "In semiconductor manufacturing processes, defect detection and recognition in wafer maps have received increasing attention from semiconductor industry. The various defect patterns in wafer maps provide crucial information for assisting engineers in recognizing the root causes of the fabrication problems and solving them eventually. This paper develops a manifold learning based wafer map defect detection and recognition system. In this system, a joint local and nonlocal linear discriminant analysis (JLNDA) is proposed to discover intrinsic manifold information that provides the discriminant characteristics of the defect patterns. An unsupervised version of JLNDA (called local and nonlocal preserving projection) is further developed to provide a monitoring chart for defect detection of wafer maps. A JLNDA based Fisher discriminant is further put forward for online defect recognition without the modeling procedure of recognizers. Comparisons with other regular methods, principal component analysis, local preserving projection, linear discriminant analysis (LDA) and local LDA, illustrate the superiority of JLNDA in wafer map defect recognition. The effectiveness of the proposed system has been verified by experimental results from a real world data set of wafer maps (WM 811K)", "author_names": [ "Jianbo Yu", "Xiaolei Lu" ], "corpus_id": 7412635, "doc_id": "7412635", "n_citations": 59, "n_key_citations": 7, "score": 0, "title": "Wafer Map Defect Detection and Recognition Using Joint Local and Nonlocal Linear Discriminant Analysis", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2016 }, { "abstract": "In Part I, we have established a wafer scale, CMOS compatible graphene transfer for the back end of the line integration. In Part II of this paper, we analyze statistical data of device properties and draw conclusions about possible causes of device failure. Statistical analysis is performed for device mobility and compared with the yield analysis. To complement this analysis, detailed Raman spectra are employed to analyze strain. In addition, device models developed in Part I are examined and provide further insight. From the analysis, it appears that compressive strain introduced during the graphene transfer process is may be the primary source for device failure. Moreover, we speculate based on the device statistics that the mitigation of compressive strain will improve device mobility, carrier density, and reduce variability. In addition, the presence of residues, tears, and cracks in the graphene may result in some device failure.", "author_names": [ "Anderson David Smith", "Stefan Wagner", "Satender Kataria", "Bengt Gunnar Malm", "Max Christian Lemme", "Mikael Ostling" ], "corpus_id": 33180551, "doc_id": "33180551", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Wafer Scale Statistical Analysis of Graphene Field Effect Transistors Part II: Analysis of Device Properties", "venue": "IEEE Transactions on Electron Devices", "year": 2017 }, { "abstract": "We analyze the completion time of wafer lots in single armed cluster tools with parallel processing modules (PMs) by considering the lot switching operation. To effectively assign wafer lots and dispatch overhead hoist transports (OHTs) to manufacturing tools, it is crucial to obtain the completion time of wafer lots. However, estimating the completion time is not straightforward, due to the concurrent processing of two consecutive wafer lots during lot switching operation, which often increases wafer sojourn times in PMs. In this paper, we derive closed form expressions of the completion time of wafer lots in single armed cluster tools with parallel PMs. We assume that the robot unloads wafers in the order of their loading sequence. We then experimentally show that the formulas derived can be used even when processing time variation exists or another robot task sequence, which is of first in first out (FIFO) is assumed.Note to Practitioners Due to the larger wafer size and circuit width reduction, cluster tools often perform the lot switching operation with each pair of consecutive wafer lots. In addition, since most tools are operated with parallel chambers, concurrent processing with two different wafer lots occurs frequently. Such transient periods in operating tools make it hard to estimate the completion time of wafer lots. In this paper, we derive closed form expressions to obtain the completion time of wafer lots in single armed cluster tools with parallel chambers. We further show that the formulas can be used with processing time variation or the FIFO rule. With the formulas, OHTs can be sent just in time to tools to load or unload wafer cassettes, and wafer lots can be assigned while minimizing the transient periods. In addition, the estimated completion time can be utilized in the planning and scheduling of wafer fabrication processes.", "author_names": [ "Jun-Ho Lee", "Hyun-Jung Kim" ], "corpus_id": 19940033, "doc_id": "19940033", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Completion Time Analysis of Wafer Lots in Single Armed Cluster Tools With Parallel Processing Modules", "venue": "IEEE Transactions on Automation Science and Engineering", "year": 2017 }, { "abstract": "Wafer scale, CMOS compatible graphene transfer has been established for device fabrication and can be integrated into a conventional CMOS process flow back end of the line. In Part I of this paper, statistical analysis of graphene FET (GFET) devices fabricated on wafer scale is presented. Device yield is approximately 75% (for 4500 devices) measured in terms of the quality of the top gate, oxide layer, and graphene channel. Statistical evaluation of the device yield reveals that device failure occurs primarily during the graphene transfer step. In Part II of this paper, device statistics are further examined to reveal the primary mechanism behind device failure. The analysis from Part II suggests that significant improvements to device yield, variability, and performance can be achieved through mitigation of compressive strain introduced in the graphene layer during the graphene transfer process. The combined analyses from Parts I and II present an overview of mechanisms influencing GFET behavior as well as device yield. These mechanisms include residues on the graphene surface, tears, cracks, contact resistance at the graphene/metal interface, gate leakage as well as the effects of postprocessing.", "author_names": [ "Anderson David Smith", "Stefan Wagner", "Satender Kataria", "Bengt Gunnar Malm", "Max Christian Lemme", "Mikael Ostling" ], "corpus_id": 27259444, "doc_id": "27259444", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Wafer Scale Statistical Analysis of Graphene FETs Part I: Wafer Scale Fabrication and Yield Analysis", "venue": "IEEE Transactions on Electron Devices", "year": 2017 } ]

[ { "abstract": "We theoretically investigate the high order harmonic generation (HHG) from laser solid interaction in a doped semiconductor by solving the one dimensional time dependent Schrodinger equation within the single active electron model. The results show that the energy band of the valence and the low conduction band can be split into a small band in the doped semiconductor. The splitting band gap can be controlled by changing the depth of the potential well of the doped semiconductor, and the second HHG plateau can be enhanced. We also demonstrate the energy band structures in coordinate space with different numbers of dopant. Time dependent population imaging is used to illustrate the change of the splitting band gap with different depths of the potential well of the doped semiconductor.", "author_names": [ "Xue-Fei Pan", "Tao Han", "C L Xia", "Tong-Tong Xu", "Jingdong Zhang", "Xueshen Liu" ], "corpus_id": 209995112, "doc_id": "209995112", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Energy band splitting and high order harmonic generation from a doped semiconductor", "venue": "Laser Physics Letters", "year": 2019 }, { "abstract": "We investigate the high order harmonic generation (HHG) in doped semiconductors. The HHG is simulated with the single electron time dependent Schr\\\"{o}dinger equation (TDSE) The results show that the high order harmonics in the second plateau generated from the doped semiconductors is about 1 to 3 orders of magnitude higher than those from the undoped semiconductor. The results are explained based on the analysis of the energy band structure and the time dependent population imaging. Our work indicates that doping can effectively control the HHG in semiconductor.", "author_names": [ "Tengfei Huang", "Xiaosong Zhu", "Liang Li", "Xi Liu", "Pengfei Lan", "Peixiang Lu" ], "corpus_id": 119077953, "doc_id": "119077953", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "High order harmonic generation of a doped semiconductor", "venue": "", "year": 2017 }, { "abstract": "We investigate the high order harmonic generation (HHG) in doped semiconductors. The HHG is simulated with the single electron time dependent Schrodinger equation (TDSE) The results show that the high order harmonics in the second plateau generated from the doped semiconductors is about 1 to 3 orders of magnitude higher than those from the undoped semiconductor. The results are explained based on the analysis of the energy band structure and the time dependent population imaging. Our work indicates that doping can effectively control the HHG in semiconductor.", "author_names": [ "Tengfei Huang", "Xiaosong Zhu", "Liang Li", "Xi Liu", "Pengfei Lan", "Peixiang Lu" ], "corpus_id": 62814372, "doc_id": "62814372", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "2 3 O ct 2 01 7 High order harmonic generation of doped semiconductor", "venue": "", "year": 2018 }, { "abstract": "The development of new and inexpensive semiconductor electrodes that possess suitable band gap energies and band positions for solar water splitting is of great interest in the field of solar fuel production. In this study, n type Cu11V6O26 that has a band gap energy of 1.9 eV was produced as a pure, high quality photoanode, and its properties and stability for photoelectrochemical water splitting were systematically investigated in pH 9.2 and 13 solutions. As Cu11V6O26 photoanodes appeared to suffer from poor charge transport properties, Mo and W doping into the V site was also examined, which considerably improved the photocurrent generation of Cu11V6O26. The band gap energy, band edge positions, flatband potential, photocurrent generation, and photostability of pristine and doped Cu11V6O26 electrodes are discussed in comparison to elucidate the effect of Mo and W doping and to evaluate the promise and limitations of Cu11V6O26 as a photoanode for use in a water splitting photoelectrochemical cell.", "author_names": [ "Margaret A Lumley", "Kyoung-Shin Choi" ], "corpus_id": 103797832, "doc_id": "103797832", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Investigation of Pristine and (Mo, W) Doped Cu11V6O26 for Use as Photoanodes for Solar Water Splitting", "venue": "", "year": 2017 }, { "abstract": "The wavelength scaling of the cutoff energy in solid high harmonic generation (HHG) is investigated theoretically by separating the contributions into the intraband and interband components. We find that, the cutoff energies of intraband and interband HHG exhibit the essentially different wavelength dependences. Specifically, the cutoff energy of the intraband HHG is wavelength independent, whereas the cutoff energy of the interband HHG depends linearly on the laser wavelength. Our results can uniformly interpret two current different wavelength scalings of the cutoff energy reported in previous researches. The fundamentally different wavelength scalings of the cutoff energy for intraband and interband HHG can be used to distinguish the two mechanisms. (c) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (270.6620) Strong field processes; (190.4160) Multiharmonic generation; (190.4720) Optical nonlinearities of condensed matter. References and links 1. F. Krausz, and M. Ivanov, \"Attosecond physics,\" Rev. Mod. Phys. 81, 163 234 (2009) 2. P. B. Corkum, and F. Krausz, \"Attosecond science,\" Nat. Phys. 3, 381 387 (2007) 3. X. Ma, M. Li, Y. Zhou, and P. Lu, \"Nonsequential double ionization of Xe by mid infrared laser pulses,\" Opt. Quantum Electron. 49, 170 (2017) 4. Y. Zhou, M. Li, Y. Li, A. Tong, Q. Li, and P. Lu, \"Dissection of electron correlation in strong field sequential double ionization using a classical model,\" Opt. Express 25, 8450 8458 (2017) 5. P. B. Corkum, \"Plasma perspective on strong field multiphoton ionization,\" Phys. Rev. Lett. 71, 1994 1997 (1993) 6. M. Lewenstein, P. Balcou, M. Y. Ivanov, A. L'Huillier, and P. B. Corkum, \"Theory of hihg harmonic generation by low frequency laser fields,\" Phys. Rev. A 49, 2117 2132 (1994) 7. M. Hentschel, R. Kienberger, C. Spielmann, G. A. Reider, N. Milosevic, T. Brabec, P. Corkum, U. Heinzmann, M. Drescher, and F. Krausz, \"Attosecond metrology,\" Nature 414, 509 513 (2001) 8. P. M. Paul, E. S. Toma, P. Breger, G. Mullot, F. Auge, P. Balcou, H. G. Muller, and P. Agostini, \"Observation of a Train of Attosecond Pulses from High Harmonic Generation,\" Science 292, 1689 1692 (2005) 9. L. Li, Z. Wang, F. Li, and H. Long, \"Efficient generation of highly elliptically polarized attosecond pulses,\" Opt. Quantum Electron. 49, 73 (2017) 10. C. Yu, H. He, Y. Wang, Q. Shi, Y. Zhang, and R. Lu, \"Intense attosecond pulse generated from a molecular harmonic plateau of H+2 in mid infrared laser fields,\" J. Phys. B: At. Mol. Opt. Phys. 47, 055601 (2014) 11. J. Itatani, J. Levesque, D. Zeidler, H. Niikura, H. Pepin, J. C. Kieffer, P. B. Corkum, and D. M. Villeneuve, \"Tomographic imaging of molecular orbitals,\" Nature 432, 867 871 (2004) 12. S. Haessler, J. Caillat, W. Boutu, C. Giovanetti Teixeira, T. Ruchon, T. Auguste, Z. Diveki, P. Breger, A. Maquet, B. Carre, R. Taieb, and P. Salieres, \"Attosecond imaging of molecular electronic wavepackets,\" Nat. Phys. 6, 200 206 (2010) 13. C. Zhai, X. Zhu, P. Lan, F. Wang, L. He, W. Shi, Y. Li, M. Li, Q. Zhang, and P. Lu, \"Diffractive molecular orbital tomography,\" Phys. Rev. A 95, 033420 (2017) 14. X. Liu, P. Li, X. Zhu, P. Lan, Q. Zhang, and P. Lu, \"Probing the p p* transitions in conjugated compounds with an infrared femtosecond laser,\" Phys. Rev. A 95, 033421 (2017) 15. P. Lan, M. Ruhmann, L. He, C. Zhai, F. Wang, X. Zhu, Q. Zhang, Y. Zhou, M. Li, M. Lein, and P. Lu, \"Attosecond Probing of Nuclear Dynamics with Trajectory Resolved High Harmonic Spectroscopy,\" Phys. Rev. Lett. 119, 033201 (2017) Vol. 25, No. 23 13 Nov 2017 OPTICS EXPRESS 29216 #308402 https:/doi.org/10.1364/OE/25.029216 Journal (c) 2017 Received 2 Oct 2017; revised 1 Nov 2017; accepted 2 Nov 2017; published 8 Nov 2017 16. S. Ghimire, A. D. DiChiara, E. Sistrunk, P. Agostini, L. F. DiMauro, and D. A. Reis, \"Observation of high order harmonic generation in a bulk crystal,\" Nat. Phys. 7, 138 141 (2011) 17. T. T. Luu,M.Garg, S. Y. Kruchinin, A.Moulet,M. T. Hassan, and E. Goulielmakis, \"Extreme ultraviolet high harmonic spectroscopy of solids,\" Nature 521, 498 502 (2015) 18. H. Long, L. Bao, A. A. Habeeb, and P. Lu, \"Effects of doping concentration on the surface plasmonic resonances and optical nonlinearities in AGZO nanotriangle arrays,\" Opt. Quantum Electron. 49, 345 (2017) 19. G. Vampa, T. J. Hammond, N. Thire, B. E. Schmidt, F. Legare, C. R. McDonald, T. Brabec, D. D. Klug, and P. B. Corkum, \"All Optical Reconstruction of Crystal Band Structure,\" Phys. Rev. Lett. 115, 193603 (2015) 20. A. A. Lanin, E. A. Stepanov, A. B. Fedotov, and A. M. Zheltikov, \"Mapping the electron band structure by intraband high harmonic generation in solids,\" Optica 4, 516 519 (2017) 21. C. M. Wang, T. S. Ho, and S. I. Chu, \"Determination of band structure from the intra band power spectrum of high harmonic generation in crystal,\" J. Phys. B: At. Mol. Opt. Phys. 49, 225401 (2016) 22. M. Schultze, K. Ramasesha, C. D. Pemmaraju, S. A. Sato, D. Whitmore, A. Gandman, J. S. Prell, L. J. Borja, D. Prendergast, K. Yabana, D. M. Neumark, and S. R. Leone, \"Attosecond band gap dynamics in silicon,\" Science 346, 1348 1352 (2014) 23. M. Hohenleutner, F. Langer, O. Schubert, M. Knorr, U. Huttner, S. W. Koch, M. Kira, and R. Huber, \"Real time observation of interfering crystal electrons in high harmonic generation,\" Nature 523, 572 575 (2015) 24. S. Jiang, C. Yu, G. Yuan, T. Wu, Z. Wang, and R. Lu, \"Quantum trajectory analysis for charge transfer in solid materials induced by strong laser felds,\" J. Phys. Condens. Matter 29, 275702 (2017) 25. T. Higuchi, M. I. Stockman, and P. Hommelhoff, \"Strong Field Perspective on High Harmonic Radiation from Bulk Solids,\" Phys. Rev. Lett. 113, 213901 (2014) 26. S. Ghimire, A. D. DiChiara, E. Sistrunk, G. Ndabashimiye, U. B. Szafruga, A. Mohammad, P. Agostini, L. F. DiMauro, and D. A. Reis, \"Generation and propagation of high order harmonics in crystals,\" Phys. Rev. A 85, 043836 (2012) 27. S. Ghimire, G. Ndabashimiye, A. D. DiChiara, E. Sistrunk, M. I. Stockman, P. Agostini, L. F. DiMauro, and D. A. Reis, \"Strong field and attosecond physics in solids,\" J. Phys. B: At. Mol. Opt. Phys. 47, 204030 (2014) 28. E. N. Osika, A. Chacon, L. Ortmann, N. Suarez, J. A. Perez Hernandez, B. Szafran, M. F. Ciappina, F. Sols, A. S. Landsman, and M. Lewenstein, \"Wannier Bloch Approach to Localization in High Harmonics Generation in Solids,\" Phys. Rev. X 7, 021017 (2017) 29. G. Vampa, C. R. McDonald, G. Orlando, P. B. Corkum, and T. Brabec, \"Semiclassical analysis of high harmonic generation in bulk crystals,\" Phys. Rev. B 91, 064302 (2015) 30. Z. Guan, X. X. Zhou, and X. B. Bian, \"High order harmonic generation from periodic potentials driven by few cycle laser pulses,\" Phys. Rev. A 93, 033852 (2016) 31. M. Wu, S. Ghimire, D. A. Reis, K. J. Schafer, and M. B. Gaarde, \"High harmonic generation from Bloch electrons in solids,\" Phys. Rev. A 91, 043839 (2015) 32. M. Wu, D. A. Browne, K. J. Schafer, and M. B. Gaarde, \"Multilevel perspective on high order harmonic generation in solids,\" Phys. Rev. A 94, 063403 (2016) 33. L. A. Chizhova, F. Libisch, and J. Burgdorfer, \"High harmonic generation in graphene: Interband response and the harmonic cutoff,\" Phys. Rev. B 95, 085436 (2017) 34. N. Tancogne Dejean, O. D. Mucke, F. X. Kartner, and A. Rubio, \"Impact of the Electronic Band Structure in High Harmonic Generation Spectra of Solids,\" Phys. Rev. Lett. 118, 087403 (2017) 35. J. C. Slater, \"A Soluble Problem in Energy Bands,\" Phys. Rev. 87, 808 (1952) 36. T. Y. Du, Z. Guan, X. X. Zhou, and X. B. Bian, \"Enhanced high order harmonic generation from periodic potentials in inhomogeneous laser fields,\" Phys. Rev. A 94, 023419 (2016) 37. X. Liu, X. Zhu, P. Lan, X. Zhang, D. Wang, Q. Zhang, and P. Lu, \"Time dependent population imaging for high order harmonic generation in solids,\" Phys. Rev. A 95, 063419 (2017) 38. J. B. Li, X. Zhang, S. J. Yue, H. M. Wu, B. T. Hu, and H. C. Du, \"Enhancement of the second plateau in solid high order harmonic spectra by the two color fields,\" Opt. Express 25, 18603 18613 (2017) 39. T. Huang, X. Zhu, L. Li, X. Liu, P. Lan, and P. Lu, \"High order harmonic generation of doped semiconductor,\" Phys. Rev. A 96, 043425 (2017) 40. T. Ikemachi, Y. Shinohara, T. Sato, J. Yumoto, M. Kuwata Gonokami, and K. L. Ishikawa, \"Trajectory analysis of high order harmonic generation from periodic crystals,\" Phys. Rev. A 95, 043416 (2017) 41. M. D. Feit, J. A. Fleck, Jr. and A. Steiger, \"Solution of the Schrodinger equation by a spectral method,\" J. Comput. Phys. 47, 412 433 (1982) 42. G. Vampa, C. R. McDonald, G. Orlando, D. D. Klug, P. B. Corkum, and T. Brabec, \"Theoretical Analysis of High Harmonic Generation in Solids,\" Phys. Rev. Lett. 113, 073901 (2014) 43. C. R. McDonald, G. Vampa, P. B. Corkum, and T. Brabec, \"Interband Bloch oscillation mechanism for high harmonic generation in semiconductor crystals,\" Phys. Rev. A 92, 033845 (2015) 44. C. Yu, X. Zhang, S. Jiang, X. Cao, G. Yuan, T. Wu, L. Bai, and R. Lu, \"Dependence of high order harmonic generation on dipole moment in SiO2 crystals,\" Phys. Rev. A 94, 013846 (2016) 45. C. Liu, Y. Zheng, Z. Zeng, and R. Li, \"Effect of elliptical polarization of driving field on high order harmonic generation in semiconductor ZnO,\" Phys. Rev. A 93, 043806 (2016) 46. U. Elu, M. Baudisch, H. Pires, F. Tani, M. H. Frosz, F. Kottig, A. Ermolov, P. ST.J. Russell, and J. Biegert, \"High average power and single cycle pulses from a mid IR optical parametric chirped pulse amplifier,\" Optica 4, Vol. 25, No. 23 13 Nov 2017 OPTICS EXPRESS 29217", "author_names": [ "" ], "corpus_id": 221822622, "doc_id": "221822622", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wavelength scaling of the cutoff energy in the solid high harmonic generation", "venue": "", "year": 2017 }, { "abstract": "Abstract Hydrogen generation from photoelectrochemical (PEC) water splitting is on the forefront of clean energy generation landscape. The efficiency of PEC system is dependent on the engineering of semiconductors with tailored narrow band gap coupled with superior photoelectrochemical activity and desired stability vital for the commercialization of PEC water splitting cells. We report herein the study of vertically aligned Nb and N doped SnO2 nanotubes (NTs) i.e. (Sn0.95Nb0.05)O2:N NTs for PEC water splitting. (Sn0.95Nb0.05)O2 NTs was selected for co doping with nitrogen by systematic analysis of applied bias photon to current efficiency of various Nb doped SnO2 (x 0 0.1) compositions. Consequently, excellent photoelectrochemical stability and the highest efficiency of 4.1% is obtained for (Sn0.95Nb0.05)O2:N 600 NTs never observed for other known TiO2, ZnO, and Fe2O3 systems to date. Additionally, theoretical first principles study provides understanding of Nb and N co doping on the electronic structure and band gap of SnO2 semiconductor, further corroborating results of the experimental study.", "author_names": [ "Prasad Prakash Patel", "Prashanth Jampani Hanumantha", "Oleg I Velikokhatnyi", "Moni Kanchan Datta", "Bharat Gattu", "James A Poston", "Ayyakkannu Manivannan", "Prashant N Kumta" ], "corpus_id": 100780008, "doc_id": "100780008", "n_citations": 23, "n_key_citations": 2, "score": 0, "title": "Vertically aligned nitrogen doped (Sn,Nb)O2 nanotubes Robust photoanodes for hydrogen generation by photoelectrochemical water splitting", "venue": "", "year": 2016 }, { "abstract": "Ionization threshold in a semiconductor is determined through the value of band gap energy (Eg, 1 eV to 5 eV) which monitors the avalanche breakdown phenomenon of corresponding reverse biased p n junctions. Further the p n junction under avalanche breakdown can generate high frequency (hf) power (between 10 and 400GHz and beyond) in Impatt mode, as negative resistance oscillator, performance of which again depends on band gap energy of the semiconductor. Computer aided studies on breakdown and hf performance characteristics of flat DD (ppnn) Impatts based on conventional materials with moderate band gap energy Si, GaAs and InP having Eg=1.12, 1.36 and 1.26 eV respectively) as well as wide band gap semiconductors (ZnS, SiC and GaN, with respectively values of Eg =3.68, 2.9 and 3.4 eV) are presented. The p n junctions of materials having wide band gap energy needs sufficiently high reverse electric field/reverse bias voltage to initiate avalanche breakdown, as compared to the same for materials with low gap. For 3 micron pp nn type flat doped junction, the breakdown field and breakdown voltage for ZnS diode become 170 V/micron and 661 V respectively as against 40 V/micron and 72 V for corresponding Si junction. Similar trend has been observed for SiC, GaN and InP, GaAs diode junctions. The rf analysis of the corresponding Impatt diodes shows that the Device efficiency (21.1% and negative resistance (0.228 x 10 O.m) for 60 GHz (1 micron) ZnS DDRs are respectively around 1.9, 2.4 times of the values of the same parameters of corresponding Silicon DDR. The inherent avalanche noise associated with ZnS diode has been computed to be only 7% of the noise generated in Si Impatt diode. The performance of ZnS diode is also compared 230 Shankar P. Pati, Pravash R. Tripathy and Santosh K. Dash with diodes based on GaAs, InP, GaN and SiC diodes. The computed value of efficiency rf power output remains low, noise level becomes high for GaAs, InP, SiC and GaN devices compared to ZnS DDD. Computed values of rf power from 60 GHz Si, GaAs, InP, SiC, GaN and ZnS DDRs have been found respectively to be 18.9, 66.65, 119.95, 1532.7, 979.99 and 1987.4 W. RF power generation also have been investigated by considering respective diode area to be 50a, 10a, 5a,2a, and a where a is 10m for different frequency ranges (11 GHz 140GHz) for ZnS based IMPATTs which indicates similar trend of high rf power realization from ZnS DDDs in this entire frequency range. Indexing Terms: Band Gap Energy, ZnS, GaN, SiC, InP, GaAs, Si, Flat DDD, Impatt, mm power, Avalanche Noise. Introduction Ionization threshold in a semiconductor is determined through the value of band gap energy (normally the value of band gap energy, Eg, remains in the range of 0.66 eV to 5.1 eV for practical semiconductors) which monitors the avalanche breakdown phenomenon of reverse biased p n junctions based on the same semiconductor. Further reverse biased p n junction under avalanche breakdown can generate high frequency (hf) power (fundamental frequency ranges between 10 and 400 GHz) in impatt mode, as negative resistance oscillator, performance of which is supposed to depend on band gap energy of the semiconductor. Under harmonic mode the frequency can be still pushed to 1000 GHz, which is usually not achievable by any other solid state semiconductor device. Further advantage of impatt class of device is that the junction device can be fabricated from any semiconductor as the device physics is not typical to particular semiconductor. The negative resistance is produced due to combined phenomena of transit time delay and avalanche phase delay, making the total phase delay between rf current and voltage between p/2 and 3p/2. The efficiency and rf power output fall when the frequency is pushed to mm wave/submm wave bands. Research work is being carried out by different groups of scientists/engineers to enhance the efficiency and mm wave power from this class of device even at beyond mm wave frequencies. New materials are being studied and explored for impatt diodes with a view to achieve the above mentioned objectives. The indication from report of better microwave performance from GaAs and InP impatt over silicon diode due their higher band gap provides motive to study the device characteristics of wide gap semiconductor based impatt diodes vis a vis impatt diodes fabricated from narrow gap semiconductor. The authors have selected ZnS, SiC GaN (respective values of Eg =3.68, 2.9 and 3.4eV) as prospective wide band semiconductors and considered Si, InP GaAs (having Eg=1.12, 1.36 and 1.26 eV respectively) as moderate band gap semiconductors and compared breakdown as well as hf characteristics of p n junction impatts with above mentioned base semiconductors. The properties of ZnS impatt diodes are observed to excel over the rest. This has given reasons to the authors to provide due emphasis to ZnS as one Avalanche Breakdown Charecteristics of Wide 231 prospective material for high efficiency and high rf power generation associated with low noise. Since the device technology is now very advanced and a lot of experimental reports are available on Silicon Impatts, first the properties of ZnS Impatts are compared with those of Silicon diodes. A review of recent reports [1 4] on high field transport properties and ionization rate data in ZnS indicate some interesting features like very high value of electron ionization rate at electric field above 1.5x10 V/m and its sharp fall below this field. These properties are supposed to identify ZnS as a prospective material for impatt device. Flat doped ZnS impatt diodes (pp nn) have been analyzed for a wide range of doping/frequencies through use of a three phase generalized computer algorithm, which can be used to compute microwave/mm wave properties and also to estimate the generation of avalanche noise for any form of impatt represented in figure 1. The results have been compared with Si Impatts designed for corresponding frequencies. The results indicate high values of breakdown electric field (Em) and breakdown voltage (VB) for ZnS diode. The avalanche zone becomes localized leading to possible realization of optimum high efficiency (e 28% at 18 GHz) and enhanced value of diode negative resistance (Zr) High VB would make the diode capable of handling high power and high e and Zr help in producing high rf power. In addition the computed value of mean square avalanche noise voltage (NV) and Noise measure (NM) are observed to be lower by an order of magnitude compared to corresponding conventional devices based on common semiconductors. However, the advantages of ZnS impatts are observed to be moderated at frequencies beyond 140 GHz. Thus ZnS may prove to be a promising high Eg material for use in Impatt diode fabrication in order to realize high rf power with high e and low noise form X band to D band (10140 GHz) Analysis also has been carried out for Impatt diodes based on GaAs InP low band gap materials and SiC GaN wide band gap materials IMPATTs. A comparative account of the rf performance of the devices are presented in this paper which indicates possibility of high mm wave power generation associated with low noise from ZnS devices compared to Si, GaAs, InP, SiC and GaN based Impatts. 232 Shankar P. Pati, Pravash R. Tripathy and Santosh K. Dash Figure 1: Schematic Double Drift Structure of Impatt Diode. Theory and Simulation Method Extracting the values of electron ionization rate (a) at different electric field values [2] a usual exponential (a=a.exp b/Eg) as well as high order polynomial form (a=a0+a1E+a2E +a3E +anE of equations for a~E, are framed following usual curve fitting technique. The values of 'a' 'b' and g in the exponential form and those of a1 to a8 are determined/used for the high field and low field zones. The drift velocities are taken from [4] The electron and hole ionization rate are taken to be equal as ZnS is a very wide band gap semiconductor. Ionization rate, drift velocities and other material parameters for other semiconductors are taken from recent available experimental reports. A double iterative computer method to solve Poison, Carrier Continuity and space charge equations simultaneously subject to fulfillment of boundary conditions in electric field and carrier currents has been framed ensuring speedy convergence. The basic equations for DC analysis are, Poisson's equation, x E q (ND NA+p n) (1) and the current continuity equation is given by,", "author_names": [ "Shankar P Pati", "Kaushik Dash", "Pravash R Tripathy", "Santosh Kumar Dash" ], "corpus_id": 219544286, "doc_id": "219544286", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Avalanche Breakdown Characteristics of Wide Band GaP vis a vis Low Band Gap Junctions and High RF Power/Low Noise Generation in ZnS DD IMPATTs", "venue": "", "year": 2010 }, { "abstract": "Abstract The generation of hydrogen and oxygen from the photocatalytic water splitting reaction under visible light is a promisingly renewable and clean source for H2 fuel. The transition metal oxide semiconductors (e.g. TiO2, WO3, ZnO, and ZrO2) are have been widely used as photocatalysts for the hydrogen generation. Because of safety, low cost, chemical inertness, photostability and other characteristics (bandgap, corrosion resistance, thermal and environmental stability) TiO2 is considered as a most potential catalyst of the semiconductors being investigated and developed. However, the extensive applications of TiO2 are hampered by its inability to exploit the solar energy of visible region. Other demerits are lesser absorbance under visible light, and recombination of photogenerated electron hole pairs. In this review, we focus on the all the possible reactions taking place at the catalyst during photo induced H2 from water splitting reaction, which is green and promising technology. Various parameter affecting the photocatalytic water splitting reactions are also studied. Predominantly, this review is focussed on bandgap engineering of TiO2 such as the upward shift of valence band and downward shift of conduction bands by doping process to extend its light absorption property into the visible region. Furthermore, the recent advances in this direction including various new strategies of synthesis, multiple doping, hetero junction, functionalization, perspective and future opportunities of non metals doped TiO2 based nanostructured photocatalysts for various photocatalytic applications such as efficient hydrogen production, air purification and CO2 reduction to valuable chemicals have been discussed.", "author_names": [ "Shivaraj B Patil", "Patil S Basavarajappa", "Nagaraju Ganganagappa", "M S Jyothi", "Anjanapura V Raghu", "Kakarla Raghava Reddy" ], "corpus_id": 145892757, "doc_id": "145892757", "n_citations": 109, "n_key_citations": 0, "score": 0, "title": "Recent advances in non metals doped TiO2 nanostructured photocatalysts for visible light driven hydrogen production, CO2 reduction and air purification", "venue": "International Journal of Hydrogen Energy", "year": 2019 }, { "abstract": "Summary form only given. High power ultrashort pulse lasers that operate around 2mm spectral region are of particular interest in expanding access to broadband coherent source options for the mid infrared spectral region. For example, such optical frequency comb generators can be utilized for real time, high sensitivity and high resolution detection of absorption features of molecular species present in the so called \"molecular fingerprint\" region. Amongst other potential implementations of 2 mm ultrafast lasers are free space optical communications, high harmonic generation, infrared pulsed laser ablation of polymer materials and surgery. Tm doped crystalline gain media could offer an attractive route towards the development of high power and efficient ultrashort pulse lasers for the 2 mm spectral region as alternatives to fiber [1] or semiconductor thin disk laser [2] approaches for which only rather limited average powers have been reported to date. For such purposes, Tm doped crystals having characteristic broadband and relatively homogeneous gain spectra extending beyond 2 mm (that avoid strong water absorption at l<;1950 nm) are required. Additionally, such media should support efficient cross relaxation processes in a Tm Tm manifold for efficient conversion of the pump radiation at 800 nm to laser emission around 2 mm and, as more general requirement, they possess good thermo mechanical properties.Here we report our recent results on femtosecond mode locking of Tm doped sesquioxides (Sc2O3, Lu2O3 and LuScO3) in the 2.0 2.1 mm region. The distinguishing features of these media include strong ground level Stark splitting that results in the emission spectra that extend beyond 2100 nm and superior thermo mechanical properties. All the experimental assessments were carried out with a Ti:sapphire pump laser (that produced up to 2.6 W at 796 nm) and an asymmetric, astigmatically compensated Z fold resonator which was configured with two high reflectivity (R 99.2% from 1770 to 2100 nm) folding mirrors having radii of curvature of 100 mm, an output coupling of 1.2% 2.3% or 4% and a SESAM. The SESAMs used for passive mode locking initiation and stabilization are based on an ion implanted InGaAsSb quantum well structure and characterised by an initial reflectivity of 99.5 98% in the 1950 2100 nm range. Pairs of IR grade fused silica or CaF2 prisms were used for the intracavity group velocity dispersion control. The shortest pulse duration of 105 fs was realised with a Tm:LuScO3 crystal operating around 2010 nm (Fig. 1) because it offered the broadest emission features [3]amongst all investigated gain media. The highest average power during mode locking of up to 0.75 W was achieved with the Tm:Lu2O3 ceramic gain medium at 2070 nm for a corresponding pulse duration of 382 fs. Continuous tunability was realized from 2030 nm to 2100 nm during the mode locking of the Tm:Lu2O3 laser where pulses as short as 300 fs were generated with an average power of 430 mW at around 2040 nm. The prospects of further power and energy scaling of femtosecond Tm doped sesquioxide lasers under highpower laser diode pumping will be discussed where the generation of yet shorter pulses can be expected when optimized SESAM devices or alternative broadband absorbers based on graphene are deployed.", "author_names": [ "Alexander a Lagatsky", "Philipp Koopmann", "Oleg L Antipov", "C Tom A Brown", "Gunter Huber", "Wilson Sibbett" ], "corpus_id": 23299455, "doc_id": "23299455", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Femtosecond pulse generation with Tm doped sesquioxides", "venue": "2013 Conference on Lasers Electro Optics Europe International Quantum Electronics Conference CLEO EUROPE/IQEC", "year": 2013 }, { "abstract": "Graphene quantum dots (GQDs) have emerged as a new group of quantum confined semiconductors in recent years, with possible applications as light absorbers, luminescent labels, electrocatalysts, and photoelectrodes for photoelectrochemical water splitting. However, their semiconductor characteristics, such as the effective band gap, majority carrier type, and photochemistry, are obscured by defects in this material. Herein, we use surface photovoltage spectroscopy (SPS) in combination with photoelectrochemical measurements to determine the parameters that are essential to the use of GQDs as next generation semiconductor devices and photocatalysts. Our results show that ordered GQDs (1 6 nm) behave as p type semiconductors, based on the positive photovoltage in the SPS measurements on Al, Au, and fluorine doped tin oxide substrates, and generate mobile charge carriers under excitation of defect states at 1.80 eV and under band gap excitation at 2.62 eV. Chemical reduction with hydrazine removes some defects and increases the effective band gap to 2.92 eV. SPS measurements in the presence of sacrificial electron donor and acceptors show that photochemical charge carriers can be extracted and promote redox reactions. A reduced GQDs photocathode supports an unprecedented photocurrent of 50 mA cm 2 using K3Fe(CN)6 as sacrificial electron acceptor. Additionally, while pristine GQDs do not photoreduce protons under visible light, hydrazine treated GQDs generate H2 from aqueous methanol under visible and UV light (0.04% quantum efficiency at 375 nm) without added co catalysts. These findings are relevant to the use of GQDs in photochemical and photovoltaic energy conversion systems.", "author_names": [ "Mauricio A Melo", "Frank E Osterloh" ], "corpus_id": 51697235, "doc_id": "51697235", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Defect States Control Effective Band Gap and Photochemistry of Graphene Quantum Dots.", "venue": "ACS applied materials interfaces", "year": 2018 } ]

[ { "abstract": "In recent years, semiconductor lighting technology, also known as green lighting, has been developed rapidly. The light emitting diode (LED) is one of the most promising solid green light sources of the twenty first century.", "author_names": [ "Nan Chi" ], "corpus_id": 139619306, "doc_id": "139619306", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "The Transmitter of the Visible Light Communication System", "venue": "", "year": 2018 }, { "abstract": "The method of implementations visible light communication system and the transmitting and receiving devices, including post transmitting side data to be sent constellation modulation, maps the modulated signal to the light source corresponding to and data to be sent optical signal transmitted through; receiving end will receive the the optical signal into an electrical signal, and determines the signal constellation of modulated light source according to the received signal corresponding to the received data obtained after demodulation. In the present invention, the transmission end in accordance with the visible light source is placed constellation modulation constellation, and the data to be transmitted is a signal obtained after the modulation constellation, mapped onto constellation points corresponding to the position of light source and driving the light source, so that by an optical signal transmitted data to be sent to the receiver; the receiver terminal determines the corresponding constellation point constellation according to a modulation signal source emitting a position, to acquire data from the sender. By the process of the present invention, to achieve a visible light communication, a visible light to meet the future demand scenarios.", "author_names": [ "" ], "corpus_id": 133027750, "doc_id": "133027750", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Implemented method of visible light communication system and transmitter and receiver means", "venue": "", "year": 2013 }, { "abstract": "Due to limited interference range, the advantage of visible light communication (VLC) over wireless fidelity (WiFi) lies more in the unit area transmission rate rather than the single link transmission rate. To characterize the achievable transmission rate per unit area, we consider an indoor downlink VLC network with dense attocell configuration for the transmitters with single color light emitting diode (LED) and multi color LEDs, assuming binomial distributed users. We divide each attocell into central region and boundary region, and propose the transmission protocols based on such attocell division. We optimize the LED half power angle to maximize the mean achievable transmission rate per unit area. More specifically, we investigate the rates of cell center and cell boundary users under fairness consideration for the single LED transmitter system. We characterize the mean achievable transmission rate per unit area under the white light constraints in the multiple LEDs transmitter system. The performance of the proposed transmission protocols is evaluated by numerical results.", "author_names": [ "Jiaojiao Xu", "Chen Gong", "Jianghua Luo", "Zhengyuan Xu" ], "corpus_id": 220606788, "doc_id": "220606788", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "LED Half Power Angle Optimization for Ultra Dense Indoor Visible Light Communication Network Deployment", "venue": "IEEE Open Journal of the Communications Society", "year": 2020 }, { "abstract": "A high efficiency linear assisted Visible Light Communication (VLC) LED driver working as a transmitter is presented in this work. A linear assisted transmitter is based on the idea of using a high efficiency but bandwidth limited circuitry which delivers most of the power and a low efficiency but fast linear amplifier (linear assistance) which corrects the distortion of the signal. The presented solution takes advantage of the light in a VLC system by summing the contribution of the linear amplifier in light instead of electrically, which leads to a electrical isolation between both stages and a reduction of the complexity comparing to the traditional approach used in Envelope Tracking (ET) and Envelope Elimination and Restoration (EER) techniques. As experimental results, the design of a linear assisted Class E amplifier delivering a 16 PSK phase digital modulation with a 1 MHz carrier is presented. On one hand, the Class E amplifier delivers most of the power (92% of the signal power) at high efficiency (81 and, on the other hand, the linear amplifier only delivers the error signal at lower efficiency. The efficiency of the signal circuitry is up to 75% and the efficiency of the whole system considering the signal and the LED biasing circuitry is up to 85%", "author_names": [ "Daniel Garcia Aller", "Diego G Lamar", "Pablo Fernandez Miaja", "Juan Rodriguez", "Javier Sebastian" ], "corpus_id": 209321156, "doc_id": "209321156", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of a Linear Assisted VLC LED Transmitter Based on Summing the Light", "venue": "IECON 2019 45th Annual Conference of the IEEE Industrial Electronics Society", "year": 2019 }, { "abstract": "The emergence of visible light communication (VLC) as a subset of optical wireless communication (OWC) in the early 2000s has turned any light emitting diode (LED) source into a potential data transmitter. The design process for any VLC or OWC system typically involves a link budget analysis performed by studying the signal to noise ratio (SNR) at the receiver. Since this SNR strongly depends on the radiant flux collected by the receiver, an accurate model for this parameter is required. The point source model has been widely used since 1979 and generally provides a good approximation of the received radiant flux. However, it might be less accurate for typical extended lighting sources like LED panels or large area organic LEDs. In this paper, the radiant flux distribution of flat Lambertian rectangular or circular sources is derived from a vector analysis of their irradiance. It is then validated through actual measurements in the case of a circular source. The resulting extended source models thus better capture the light beam pattern of such transmitters to enable a more accurate link budget. It provides at the same time almost identical results to the point source model for small sources and can, therefore, be seen as a natural extension of this already widely used model.", "author_names": [ "Juan Camilo Valencia-Estrada", "Bastien Bechadergue", "Jorge Garcia-Marquez" ], "corpus_id": 220938199, "doc_id": "220938199", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Full Field Radiant Flux Distribution of Multiple Tilted Flat Lambertian Light Sources", "venue": "IEEE Open Journal of the Communications Society", "year": 2020 }, { "abstract": "Visible light communications (VLC) is a short range optical wireless communication technology that uses light emitting diodes (LEDs) as lighting devices and data transmitters. This paper describes a multiuser VLC system using Hadamard coded modulation (HCM) for indoor data transmission. Considering the peak transmitted power limit of the LEDs, a DC reduced HCM (DCR HCM) is used to reduce the nonlinear clipping distortion. Since the Hadamard codewords have different bandwidth requirements for a given symbol rate, they can be assigned to users with varying hardware capabilities. Optimally assigning codewords to users is found to significantly improve the average throughput, up to twice higher than a random assignment for a typical scenario. When the number of active users is less than the size of the Hadamard matrix used, more than one codeword can be assigned per user, which further improves the throughput. This paper also examines a scenario where multiple lamps in an indoor space transmit the same data. Since the time of arrival for the received signals emitted from different lamps is different, the Hadamard codes received are no longer orthogonal, resulting in multiple access interference and inter chip interference. The number of acceptable codewords is computed based on the specific interference experienced in different parts of the indoor space. The spatial distribution of the maximum throughput is also simulated, showing that the ratio of the maximum to the minimum data rate can be as high as 10 when considering the entire area of a typical indoor room. This article is part of the theme issue 'Optical wireless communication'", "author_names": [ "Jie Lian", "Mohammad Noshad", "Maite Brandt-Pearce" ], "corpus_id": 211573396, "doc_id": "211573396", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Indoor multiuser visible light communication systems using Hadamard coded modulation", "venue": "Philosophical Transactions of the Royal Society A", "year": 2020 }, { "abstract": "Visible light communication (VLC) is an emerging paradigm that enables multiple functionalities to be accomplished concurrently, including illumination, high speed data communications, and localization. Based on the VLC technology, visible light positioning (VLP) systems aim to estimate locations of VLC receivers by utilizing light emitting diode (LED) transmitters at known locations. VLP presents a viable alternative to radio frequency (RF) based positioning systems by providing inexpensive and accurate localization services. In this paper, we consider the problem of localization in visible light systems and provide an extensive survey of various location estimation techniques, accompanied by discussions of their relative merits and demerits within the context of accuracy and computational complexity. In addition, we investigate a cooperative VLP system architecture in which VLC receiver units are able to communicate with each other for the purpose of cooperation, and present a low complexity, iterative localization algorithm to demonstrate the benefits of cooperation in VLP systems. Finally, we investigate optimal strategies for power allocation among LED transmitters to maximize the localization accuracy subject to power and illumination constraints.", "author_names": [ "Musa Furkan Keskin", "Ahmet Dundar Sezer", "Sinan Gezici" ], "corpus_id": 44063884, "doc_id": "44063884", "n_citations": 46, "n_key_citations": 6, "score": 0, "title": "Localization via Visible Light Systems", "venue": "Proceedings of the IEEE", "year": 2018 }, { "abstract": "Mobile wireless communication heavily relies on the radio frequency to convey message and data. However, its limited spectrum can hardly meet the demands for the future high data rate applications. Optical wireless communication, in particular visible light communication, opens up vast optical spectrum for communication, and meanwhile can retrofit the light sources as the communication transmitters in the existing working or living environments. In conjunction with the ubiquitous cameras in hand held consumer electronics such as smartphones and pads, optical camera communication (OCC) further takes advantages of image sensors as the communication receivers and realizes low cost communication systems. This article first provides an overview of OCC systems. It then addresses some practical constraints, ranging from sensor low frame rate and instability, rolling shutter readout, to visual qualities of displayed images and videos, and link blockage between the transmitter and receiver. Accordingly, it introduces existing and new solutions to deal with those constraints by data modulation, newly developed camera structures, post processing of sensed signals and non line of sight OCC as a new form. In particular, indirect paths by either the indoor surface reflection or the outdoor atmospheric scattering are explored for link connectivity under blockage. Finally, some future research directions are suggested. This article is part of the theme issue 'Optical wireless communication'", "author_names": [ "Weijie Liu", "Zhengyuan Xu" ], "corpus_id": 211573400, "doc_id": "211573400", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Some practical constraints and solutions for optical camera communication", "venue": "Philosophical Transactions of the Royal Society A", "year": 2020 }, { "abstract": "Visible light communication (VLC) systems are inherently signal to noise ratio (SNR) limited due to link budget constraints. One favourable method to overcome this limitation is to focus on the pre log factors of the channel capacity. Multiple input multiple output (MIMO) techniques are therefore a promising avenue of research. However, inter channel interference in MIMO limits the achievable capacity. Spatial modulation (SM) avoids this limitation. Furthermore, the performance of MIMO systems in VLC is limited by the similarities among spatial channels. This limitation becomes particularly severe in intensity modulation/direct detection (IM/DD) systems because of the lack of phase information. The motivation of this paper is to propose a system that results in a multi channel transmission system that enables reliable multi user optical MIMO SM transmission without the need for a precoder, power allocation algorithm or additional optics at the receiver. A general bit error performance model for the SM system is developed for an arbitrary number of light emitting diodes (LEDs) in conjunction with pulse amplitude modulation. Based on this model, an LED array structure is designed to result in spatially separated multiple channels by manipulating the transmitter geometry. This article is part of the theme issue 'Optical wireless communication'", "author_names": [ "Tezcan Cogalan", "Harald Haas", "Erdal Panayirci" ], "corpus_id": 211573406, "doc_id": "211573406", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Optical spatial modulation design", "venue": "Philosophical Transactions of the Royal Society A", "year": 2020 }, { "abstract": "To support multiple users in an indoor multiple input multiple output visible light communication (MIMO VLC) system adopting spatial multiplexing, orthogonal frequency division multiple access (OFDMA) is usually adopted, where the overall modulation bandwidth is shared by all the users. In this paper, by fully exploiting the spatial distributions of light emitting diode (LED) transmitters in the ceiling and end users around the receiving plane, we propose a space division multiple access (SDMA) technique for indoor spatial multiplexing based MIMO VLC systems. When applying SDMA, users within the MIMO VLC system are divided into different user groups (UGs) based on their spatial locations with respect to different LED transmitters. Specifically, each UG can use the overall modulation bandwidth of the system. For efficient implementation of SDMA, two distributed user grouping (DUG) approaches are proposed, including basic DUG and transmit diversity enhanced DUG (TD DUG) and a two step resource allocation algorithm is further designed. The achievable rates of the MIMO VLC system employing SDMA with both basic DUG and TD DUG are derived accordingly. To verify the superiority of SDMA over conventional OFDMA, detailed analytical and simulation results are presented. Moreover, a proof of concept experiment is conducted to demonstrate the advantage of SDMA in a practical spatial multiplexing based MIMO VLC system.", "author_names": [ "Chen Chen", "Yanbing Yang", "Xiong Deng", "Pengfei Du", "Helin Yang" ], "corpus_id": 220938242, "doc_id": "220938242", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Space Division Multiple Access With Distributed User Grouping for Multi User MIMO VLC Systems", "venue": "IEEE Open Journal of the Communications Society", "year": 2020 } ]

[ { "abstract": "The objective of this paper is to monitor complex process dynamics manifest in multivariate (multidimensional) time series data using a spectral (algebraic) graph theoretic approach. We test the hypothesis that the spectral graph based topological invariants detect incipient process drifts earlier [lower average run length (ARL₁ and with higher fidelity (consistency of detection) when compared with the conventional statistics based approaches. The presented approach maps a multidimensional sensor data stream <inline formula> <tex math notation=\"LaTeX\"\\mathcal {X}{N\\times d} /tex math>/inline formula> (visualize <inline formula> <tex math notation=\"LaTeX\"$N$ /tex math>/inline formula> as time and <inline formula> <tex math notation=\"LaTeX\"$d$ /tex math>/inline formula> as the number of sensors) as an unweighted and undirected network graph <inline formula> <tex math notation=\"LaTeX\"$G(V,E) /tex math>/inline formula> indexed by its vertices <inline formula> <tex math notation=\"LaTeX\"$V$ /tex math>/inline formula> and edges <inline formula> <tex math notation=\"LaTeX\"$E$ /tex math>/inline formula> i.e. <inline formula> <tex math notation=\"LaTeX\"\\mathcal {X}\\mapsto G(V,E) /tex math>/inline formula> The rationale is that the graph based topological invariants are surrogate representatives of the system state. We compare the monitoring performance of spectral graph theoretic invariants with conventional statistical features in an exponentially weighted moving average control chart setting. The practical utility of the approach is substantiated in the context of process monitoring in two advanced manufacturing scenarios, namely, ultraprecision machining (UPM) and semiconductor chemical mechanical planarization. These studies corroborate the hypothesis that graph theoretic invariants, when used as monitoring statistics, lead to lower ARL₁ and more consistent detections in contrast to conventional statistical features. For instance, in the UPM case, the fault detection delay using graph theoretic invariants is less than 160 ms, compared with over 8 s of delay with statistical features./p><p>Note to Practitioners This paper addresses the critical problem of capturing process drifts from multidimensional (multisensor) data. The novelty of this paper is the development of a graph theoretic approach that combines signals from multiple in situ sensors for detecting abnormal process drifts. We show that this approach, which invokes graph based topological invariants instead of statistical feature mining, is capable of capturing process drifts at an earlier stage (in terms of detection delay or lower average run length) and higher consistency of detection than conventional statistical features. As a practical consequence of this research, the operator can track the status of a complex process in a tractable control chart setting with only two graph theoretic topological invariants, as opposed to complex black box models involving several features.", "author_names": [ "Mohammad Samie Tootooni", "Prahalad K Rao", "Chun-An Chou", "Zhenyu James Kong" ], "corpus_id": 31606228, "doc_id": "31606228", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "A Spectral Graph Theoretic Approach for Monitoring Multivariate Time Series Data From Complex Dynamical Processes", "venue": "IEEE Transactions on Automation Science and Engineering", "year": 2018 }, { "abstract": "The supremacy of quantum approach is able to solve the problems which are not practically feasible on classical machines. It suggests a significant speed up of the simulations and decreases the cha.", "author_names": [ "Pritpal Singh", "Gaurav Dhiman", "Amandeep Kaur" ], "corpus_id": 126244859, "doc_id": "126244859", "n_citations": 37, "n_key_citations": 0, "score": 0, "title": "A quantum approach for time series data based on graph and Schrodinger equations methods", "venue": "", "year": 2018 }, { "abstract": "In this paper, we propose a real time algorithm to realize a diagnosis of switched systems for abrupt parametric faults. This algorithm is based on interaction between a Qualitative Diagnosis (QD) and a monitoring component that performs a Qualitative Trend Analysis (QTA) of residual signals generated from Bond Graph (BG) elements called residual sinks. The QTA is applied in order to on line detect change in the mean of residual signal based on combination of Piecewise Aggregate Approximation (PAA) with Page Hinkley Test (PHT) The QD procedure is performed in two stages. In the first off line stage, Symbolic Fault Signature Matrix (SFSM) is generated from a Parameterized Temporal Causal Graph (PTCG) The PTCG is valid for all system modes and deduced from a unified Hybrid Bond Graph (HBG) model by converting its elements into node and labeled edge. Each entry in the SFSM matrix gives the residual symbolic signature which corresponds to the lower order signature predicted using the PTCG model by propagating initial deviation from the fault parameter in the label of edge to the residual node. In the second on line stage, trend extraction by linear regression is triggered after change detection in order to estimate the lower order time derivative symbol for each residual sinks. Subsequently, we propose a stepwise similarity measure for fault isolation task. The functioning of this approach is illustrated in simulating with a switched quarter car active suspension system. Hybrid BG extends the ability of BG to model switched systems using intuitive representation for structural discontinuities.HBG is used as a unified tool for a combination of Quantitative Qualitative FDI appraoch that numerically evaluate residual signalsQualitative Trend Analysis and Page Hinkley Test are used for a real time symbolic signature estimation of residual signalsCausal Graph deduced from HBG and parameterized by the state of the controlled junction is used for symbolic prediction.", "author_names": [ "Mariam Taktak", "Slim Triki", "Anas Kamoun" ], "corpus_id": 31043376, "doc_id": "31043376", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Real time algorithm based on time series data abstraction and hybrid bond graph model for diagnosis of switched system", "venue": "Eng. Appl. Artif. Intell.", "year": 2017 }, { "abstract": "Abstract Fault diagnosis of photovoltaic array plays an important role in operation and maintenance of PV power plant. The nonlinear characteristics of photovoltaic array and the Maximum Power Point Tracking technology in the inverter prevent conventional protection devices to trip under certain faults which reduces the system's efficiency and increases the risks of fire hazards. In order to better diagnose photovoltaic array faults under Maximum Power Point Tracking conditions, the sequential data of transient in time domain under faults are analyzed and then applied as the input fault features in this work. Firstly, the sequential current and voltage of the photovoltaic array are transformed into a 2 Dimension electrical time series graph to visually represent the characteristics of sequential data. Secondly, a Convolutional Neural Network structure comprising nine convolutional layers, nine max pooling layers, and a fully connected layer is proposed for the photovoltaic array fault diagnosis. The proposed model for photovoltaic array fault diagnosis integrates two main parts, namely the feature extraction and the classification. Thirdly, this model automatically extracts suitable features representation from raw electrical time series graph, which eliminates the need of using artificially established features of data and then employs for photovoltaic fault diagnosis. Moreover, the proposed Convolutional Neural Network based photovoltaic array fault diagnosis method only takes the array of voltage and current of the photovoltaic array as the input features and the reference panels used for normalization. The proposed approach of photovoltaic array fault diagnosis achieved over 99% average accuracy when applied to the case studies. The comparisons of the experimental results demonstrate that the proposed method is both effective and reliable.", "author_names": [ "Xiaoyang Lu", "Peijie Lin", "Shuying Cheng", "Yaohai Lin", "Zhicong Chen", "Lijun Wu", "Qianying Zheng" ], "corpus_id": 198346847, "doc_id": "198346847", "n_citations": 42, "n_key_citations": 2, "score": 0, "title": "Fault diagnosis for photovoltaic array based on convolutional neural network and electrical time series graph", "venue": "Energy Conversion and Management", "year": 2019 }, { "abstract": "The spatio temporal graph learning is becoming an increasingly important object of graph study. Many application domains involve highly dynamic graphs where temporal information is crucial, e.g. traffic networks and financial transaction graphs. Despite the constant progress made on learning structured data, there is still a lack of effective means to extract dynamic complex features from spatio temporal structures. Particularly, conventional models such as convolutional networks or recurrent neural networks are incapable of revealing the temporal patterns in short or long terms and exploring the spatial properties in local or global scope from spatio temporal graphs simultaneously. To tackle this problem, we design a novel multi scale architecture, Spatio Temporal U Net (ST UNet) for graph structured time series modeling. In this U shaped network, a paired sampling operation is proposed in spacetime domain accordingly: the pooling (ST Pool) coarsens the input graph in spatial from its deterministic partition while abstracts multi resolution temporal dependencies through dilated recurrent skip connections; based on previous settings in the downsampling, the unpooling (ST Unpool) restores the original structure of spatio temporal graphs and resumes regular intervals within graph sequences. Experiments on spatio temporal prediction tasks demonstrate that our model effectively captures comprehensive features in multiple scales and achieves substantial improvements over mainstream methods on several real world datasets.", "author_names": [ "Ting Yu", "Haoteng Yin", "Zhanxing Zhu" ], "corpus_id": 76666421, "doc_id": "76666421", "n_citations": 26, "n_key_citations": 3, "score": 0, "title": "ST UNet: A Spatio Temporal U Network for Graph structured Time Series Modeling", "venue": "ArXiv", "year": 2019 }, { "abstract": "Pre processing is a prerequisite to conduct effective and efficient downstream data analysis. Pre processing pipelines often require multiple routines to address data quality challenges and to bring the data into a usable form. For both the construction and the refinement of pre processing pipelines, human in the loop approaches are highly beneficial. This particularly applies to multivariate time series, a complex data type with multiple values developing over time. Due to the high specificity of this domain, it has not been subject to in depth research in visual analytics. We present a visual interactive approach for preprocessing multivariate time series data with the following aspects. Our approach supports analysts to carry out six core analysis tasks related to pre processing of multivariate time series. To support these tasks, we identify requirements to baseline toolkits that may help practitioners in their choice. We characterize the space of visualization designs for uncertainty aware pre processing and justify our decisions. Two usage scenarios demonstrate applicability of our approach, design choices, and uncertainty visualizations for the six analysis tasks. This work is one step towards strengthening the visual analytics support for data pre processing in general and for uncertainty aware pre processing of multivariate time series in particular.", "author_names": [ "Jurgen Bernard", "Marco Hutter", "Heiko Reinemuth", "Hendrik Pfeifer", "Christian Bors", "Jorn Kohlhammer" ], "corpus_id": 197627759, "doc_id": "197627759", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Visual Interactive Preprocessing of Multivariate Time Series Data", "venue": "Comput. Graph. Forum", "year": 2019 }, { "abstract": "Abstract Shield tunneling operation affects project scheduling, cost estimation, and safety risk during metro construction. Given the importance of this process, tunnel engineers should understand the complexities of shield tunneling parameters. This study addresses the characteristics of shield tunneling parameters by introducing a visibility graph model implemented in a complex network of shield tunneling in metro construction. Time series data are collected for the analysis of six parameters generated in each segment ring tunneling cycle. These parameters are total thrust, torque, penetration rate, rotation rate, advance speed, and working chamber pressure. Bridging time series and the complex network with visibility graph algorithm indicates that all degree distributions of the construct networks follow the power law, establishing the scale free time series of the parameters. Small world features and hierarchical structures also indicate that the fluctuation and variance of the parameters are attracted, limited, or affected by a previous shield operation of segment rings. In addition, findings reveal turning points in the parameters' time series with vital node identification based on complex network analysis. Implications relevant for shield operators and managers are proposed to improve shield tunneling performance, efficiency, and safety.", "author_names": [ "Cheng Zhou", "Lieyun Ding", "Ying Zhou", "Miros aw J Skibniewski" ], "corpus_id": 133165288, "doc_id": "133165288", "n_citations": 12, "n_key_citations": 0, "score": 1, "title": "Visibility graph analysis on time series of shield tunneling parameters based on complex network theory", "venue": "Tunnelling and Underground Space Technology", "year": 2019 }, { "abstract": "The unsupervised detection of anomalies in time series data has important applications, e.g. in user behavioural modelling, fraud detection, and cybersecurity. Anomaly detection has been extensively studied in categorical sequences, however we often have access to time series data that contain paths through networks. Examples include transaction sequences in financial networks, click streams of users in networks of cross referenced documents, or travel itineraries in transportation networks. To reliably detect anomalies we must account for the fact that such data contain a large number of independent observations of short paths constrained by a graph topology. Moreover, the heterogeneity of real systems rules out frequency based anomaly detection techniques, which do not account for highly skewed edge and degree statistics. To address this problem we introduce a novel framework for the unsupervised detection of anomalies in large corpora of variable length temporal paths in a graph, which provides an efficient analytical method to detect paths with anomalous frequencies that result from nodes being traversed in unexpected chronological order.", "author_names": [ "Timothy LaRock", "Vahan Nanumyan", "Ingo Scholtes", "Giona Casiraghi", "Tina Eliassi-Rad", "Frank Schweitzer" ], "corpus_id": 166228163, "doc_id": "166228163", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Detecting Path Anomalies in Time Series Data on Networks", "venue": "ArXiv", "year": 2019 }, { "abstract": "Abstract With increasing popularity of social media, Twitter has become one of the leading platforms to report events in real time. Detecting events from Twitter stream requires complex techniques. Event related trending topics consist of a group of words which successfully detect and identify events. Event detection techniques must be scalable and robust, so that they can deal with the huge volume and noise associated with social media. Existing event detection methods mostly rely on burstiness, mainly the frequency of words and their co occurrences. However, burstiness sometimes dominates other relevant details in the data which could be equally significant. Besides, the topological and temporal relationships in the data are often ignored. In this work, we propose a novel graph based approach, called the Enhanced Heartbeat Graph (EHG) which detects events efficiently. EHG suppresses dominating topics in the subsequent data stream, after their first detection. Experimental results on three real world datasets (i.e. Football Association Challenge Cup Final, Super Tuesday, and the US Election 2012) show superior performance of the proposed approach in comparison to the state of the art techniques.", "author_names": [ "Zafar Saeed", "Rabeeh Ayaz Abbasi", "Imran Razzak", "Onaiza Maqbool", "Abida Sadaf", "Guandong Xu" ], "corpus_id": 196197285, "doc_id": "196197285", "n_citations": 14, "n_key_citations": 1, "score": 0, "title": "Enhanced Heartbeat Graph for emerging event detection on Twitter using time series networks", "venue": "Expert Syst. Appl.", "year": 2019 }, { "abstract": "Narrative and storytelling have played an important role in communication. In this work, we demonstrate that the techniques of storytelling, and in particular raising attention to abnormality, can be used to add interestingness and memorability to descriptions of time series data. A computational system has been developed for automatically generating descriptions for data graphs. The system identifies visual patterns in the graph, and treats the graph's deviations from corresponding ideal patterns as abnormal events. It then uses storytelling templates to generate a graph description with the abnormal events highlighted.", "author_names": [ "Zev Battad", "Mei Si" ], "corpus_id": 53740626, "doc_id": "53740626", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Apply Storytelling Techniques for Describing Time Series Data", "venue": "ICIDS", "year": 2018 } ]

[ { "abstract": "This brief presents a cost efficient all digital CMOS digital to time converter (DTC) that innovatively applies binary weighted pulse expansion. The DTC consists of a pulse generator (PG) for pulse generation <inline formula> <tex math notation=\"LaTeX\"$t_{p} /tex math>/inline formula> a binary weighted pulse expanding circuit (BWPEC) as a main circuit for digital to time conversion, and a time subtractor (TS) for <inline formula> <tex math notation=\"LaTeX\"$t_{p} /tex math>/inline formula> removal. Compared with the original pulse expanding unit (PEU) a novel PEU with reduced complexity and a linear pulse expansion was developed for binary weighted operation. The use of the BWPEC with the binary weighted PEUs exhibits lower circuit complexity and considerably reduces the circuit cost compared to the original unary weighted pulse expanding circuit (PEC) A prototype of the 4 bit all digital DTC was fabricated using a Taiwan Semiconductor Manufacturing Company (TSMC) 0.35 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> CMOS process. The fabricated DTC exhibited an area of 0.02 mm² achieving twofold improvement considerably. The measured resolution was approximately 5 ps, with the integral nonlinearity being 1.2 1 least significant bit (LSB) Without requiring an advanced CMOS process, the pulse variation technique with a simple structure can easily achieve fine resolution. The DTC features cost efficient pulse expansion with binary weights and low circuit complexity.", "author_names": [ "Chun-Chi Chen", "Chorng-Sii Hwang", "Kai-Hsiang Chang" ], "corpus_id": 214452513, "doc_id": "214452513", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "All Digital Cost Efficient CMOS Digital to Time Converter Using Binary Weighted Pulse Expansion", "venue": "IEEE Transactions on Very Large Scale Integration (VLSI) Systems", "year": 2020 }, { "abstract": "1. Introduction. 2. Fundamentals. 3. Intensity Transformations and Spatial Filtering. 4. Frequency Domain Processing. 5. Image Restoration. 6. Color Image Processing. 7. Wavelets. 8. Image Compression. 9. Morphological Image Processing. 10. Image Segmentation. 11. Representation and Description. 12. Object Recognition.", "author_names": [ "Rafael C Gonzalez", "Richard E Woods", "Steven L Eddins" ], "corpus_id": 44708800, "doc_id": "44708800", "n_citations": 6387, "n_key_citations": 352, "score": 0, "title": "Digital image processing using MATLAB", "venue": "", "year": 2004 }, { "abstract": "The Digital Signal Processing Group develops signal processing algorithms that span a wide variety of application areas including speech and image processing, sensor networks, communications, radar and sonar. Our primary focus is on algorithm development in general, with the applications serving as motivating contexts. Our approach to new algorithms includes some unconventional directions, such as algorithms based on fractal signals, chaotic behavior in nonlinear dynamical systems, quantum mechanics and biology in addition to the more conventional areas of signal modeling, quantization, parameter estimation, sampling and signal representation.", "author_names": [ "Alan V Oppenheim", "Ronald W Schafer" ], "corpus_id": 18019078, "doc_id": "18019078", "n_citations": 849, "n_key_citations": 76, "score": 0, "title": "Digital Signal Processing", "venue": "IEEE Transactions on Systems, Man, and Cybernetics", "year": 1978 }, { "abstract": "2. A sampled (but not quantized) image, whose brightness before quantization, in each spatial position, can take values in the range [0mV;250mV] has the linear histogram of its brightness represented (approximately) in Fig. 2.a) After the quantization, the histogram of the resulting digital image is the one in Fig. 2.b) Then, most likely, the quantizer that was used is: a) an 8 bit uniform quantizer; b) a 2 bit optimal quantizer; c) a 4 bit optimal quantizer; d) a 2 bit uniform quantizer.", "author_names": [ "Rafael C Gonzalez", "Richard E Woods" ], "corpus_id": 7472395, "doc_id": "7472395", "n_citations": 7564, "n_key_citations": 914, "score": 0, "title": "Digital Image Processing", "venue": "IEEE Transactions on Pattern Analysis and Machine Intelligence", "year": 1981 }, { "abstract": "1. Introduction. 2. Discrete Time Signals and Systems. 3. The Z Transform and Its Application to the Analysis of LTI Systems. 4. Frequency Analysis of Signals and Systems. 5. The Discrete Fourier Transform: Its Properties and Applications. 6. Efficient Computation of the DFT: Fast Fourier Transform Algorithms. 7. Implementation of Discrete Time Systems. 8. Design of Digital Filters. 9. Sampling and Reconstruction of Signals. 10. Multirate Digital Signal Processing. 11. Linear Prediction and Optimum Linear Filters. 12. Power Spectrum Estimation. Appendix A. Random Signals, Correlation Functions, and Power Spectra. Appendix B. Random Numbers Generators. Appendix C. Tables of Transition Coefficients for the Design of Linear Phase FIR Filters. Appendix D. List of MATLAB Functions. References and Bibliography. Index.", "author_names": [ "John G Proakis", "Dimitris G Manolakis" ], "corpus_id": 56699897, "doc_id": "56699897", "n_citations": 3941, "n_key_citations": 236, "score": 0, "title": "Digital Signal Processing: Principles, Algorithms, and Applications", "venue": "", "year": 1992 }, { "abstract": "An integrated and comprehensive theory of PWM. The selection of the best algorithm for optimum pulse width modulation is an important process that can result in improved converter efficiency, better load (motor) efficiency, and reduced electromagnetic interference. However, the identification of the best approach is a complex process requiring extensive mathematical manipulation.", "author_names": [ "Donald Grahame Holmes", "Thomas A Lipo" ], "corpus_id": 107760500, "doc_id": "107760500", "n_citations": 2333, "n_key_citations": 321, "score": 0, "title": "Pulse Width Modulation for Power Converters: Principles and Practice", "venue": "", "year": 2003 }, { "abstract": "For courses in Digital Communications. Exceptionally accessible, this book presents the often \"difficult\" concepts of digital communications in an easy to understand manner without diluting the mathematical precision. Using a student friendly approach, it develops the important techniques in the context of a unified structure (in block diagram form) providing organization and structure to a field that has, and continues, to grow rapidly, and ensuring that students gain an awareness of the \"big picture\" even while delving into the details (the most up to date modulation, coding, and signal processing techniques that have become the basic tools of our modern era) It traces signals and key processing steps from the information source through the transmitter, channel, receiver, and ultimately to the information sink.", "author_names": [ "Bernard Sklar" ], "corpus_id": 62253895, "doc_id": "62253895", "n_citations": 477, "n_key_citations": 65, "score": 0, "title": "Digital communications fundamentals and applications", "venue": "", "year": 2020 }, { "abstract": "Optical fiber transmission is impacted by linear and nonlinear impairments. We study the use of digital backpropagation (BP) in conjunction with coherent detection to jointly mitigate dispersion and fiber nonlinearity. We propose a noniterative asymmetric split step Fourier method (SSFM) for solving the inverse nonlinear Schrodinger equation (NLSE) Using simulation results for RZ QPSK transmitted over terrestrial systems with inline amplification and dispersion compensation, we obtain heuristics for the step size and sampling rate requirements, as well as the optimal dispersion map.", "author_names": [ "Ezra Ip", "Joseph M Kahn" ], "corpus_id": 16576505, "doc_id": "16576505", "n_citations": 886, "n_key_citations": 75, "score": 0, "title": "Compensation of Dispersion and Nonlinear Impairments Using Digital Backpropagation", "venue": "Journal of Lightwave Technology", "year": 2008 }, { "abstract": "A class of digital linear phase finite impulse response (FIR) filters for decimation (sampling rate decrease) and interpolation (sampling rate increase) are presented. They require no multipliers and use limited storage making them an economical alternative to conventional implementations for certain applications. A digital filter in this class consists of cascaded ideal integrator stages operating at a high sampling rate and an equal number of comb stages operating at a low sampling rate. Together, a single integrator comb pair produces a uniform FIR. The number of cascaded integrator comb pairs is chosen to meet design requirements for aliasing or imaging error. Design procedures and examples are given for both decimation and interpolation filters with the emphasis on frequency response and register width.", "author_names": [ "Eugene B Hogenauer" ], "corpus_id": 17227048, "doc_id": "17227048", "n_citations": 1280, "n_key_citations": 87, "score": 0, "title": "An economical class of digital filters for decimation and interpolation", "venue": "", "year": 1981 }, { "abstract": "Implementing efficient and cost effective power regulation schemes for battery powered mixed signal SoCs is a key focus in integrated circuit design. This paper presents a fully integrated switched capacitor DC DC converter in 45 nm digital CMOS technology. The proposed implementation uses digital capacitance modulation instead of traditional PFM and PWM control methods to maintain regulation against load current changes. This technique preserves constant frequency switching while also scaling switching and bottom plate losses with changes in load current. Therefore, high efficiency can be achieved across different load current levels while maintaining a predictable switching noise behavior. The converter occupies only 0.16 mm2, and operates from 1.8 V input. It delivers a programmable sub 1 V power supply with efficiency as high as 69% and load current between 100 mA and 8 mA. Measurement results confirm the theoretical basis of the proposed design.", "author_names": [ "Yogesh K Ramadass", "Ayman A Fayed", "Anantha Chandrakasan" ], "corpus_id": 6448558, "doc_id": "6448558", "n_citations": 186, "n_key_citations": 13, "score": 0, "title": "A Fully Integrated Switched Capacitor Step Down DC DC Converter With Digital Capacitance Modulation in 45 nm CMOS", "venue": "IEEE Journal of Solid State Circuits", "year": 2010 } ]

[ { "abstract": "Unexpected etching of nanocrystals, nanorods, and their heterostructures by one of the most commonly used metal precursors, metal oleates, is reported. Zn oleate is shown to etch CdS nanorods anisotropically, where the length decreases without a significant change in the diameter. Sodium oleate enhances the etch rate, whereas oleic acid alone does not cause etching, indicating the importance of the countercation on the rate of oleate induced etching. Subsequent addition of Se precursors to the partially etched nanorods in Zn oleate solution can lead to epitaxial growth of CdSe particles rather than the expected ZnSe growth, despite an excess amount of Zn precursors being present. The composition of this epitaxial growth can be varied from CdSe to ZnSe, depending on the amount of excess oleic acid or the reaction temperature. Similar tuning of composition can be observed when starting with collinear CdSe/CdS/CdSe rod/rod/rod heterostructures and spherical CdS (or CdSe/CdS core/shell) nanocrystals. Conversion of collinear rod/rod/rod structures to barbells and interesting rod growth from nearly spherical particles among other structures can also result due to the initial etching effect of metal oleates. These observations have important implications on our understanding of nanocrystal heterostructure synthesis and open up new routes to varying the composition and morphology of these materials.", "author_names": [ "Nuri Oh", "Moonsub Shim" ], "corpus_id": 4963551, "doc_id": "4963551", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Metal Oleate Induced Etching and Growth of Semiconductor Nanocrystals, Nanorods, and Their Heterostructures.", "venue": "Journal of the American Chemical Society", "year": 2016 }, { "abstract": "The size and shape of CdSe nanorods, CdSe tetrapods, and CdS nanowires were tailored by chemical and photochemical etchings in chloromethane solvents. Nanocrystals were synthesized by colloidal growth, and their sizes and shapes were visualized by transmission electron microscopy before and after etching. Crystal structures were confirmed by X ray diffraction, and optical properties were monitored during etching. Chemical etching with tributylphosphine preferentially shortens the length of nanocrystals, whereas photochemical etching with both primary alkylamine and tributylphosphine reduces the diameter more than the length. The surface of etched nanocrystals was characterized by X ray photoelectron spectroscopy, and the etching products dissolved in solvent were analyzed by matrix free laser desorption ionization mass spectrometry. Spectroscopic results suggest that the chloride ion is the active species: Chloride ions are generated either by chemical activation of chloromethane solvents with tributylpho.", "author_names": [ "Sung Jun Lim", "Wonjung Kim", "Sunghan Jung", "Jongcheol Seo", "Seung Koo Shin" ], "corpus_id": 101085260, "doc_id": "101085260", "n_citations": 47, "n_key_citations": 0, "score": 1, "title": "Anisotropic Etching of Semiconductor Nanocrystals", "venue": "", "year": 2011 }, { "abstract": "Vertically aligned ZnO nanorods were grown on a SiO2/Si surface by optimization of the temperature and atmosphere for annealing of the seed. The seed layer annealed at 500 degC in vacuum provided well separated and uniform seeds which also provided the best condition to get densely packed, uniformly distributed, and vertically aligned nanorods. These nanorods grown on the substrates were used to fabricate electrolyte insulator semiconductor (EIS) devices for pH sensing. Etching of ZnO at acidic pH prevents the direct use of nanorods for pH sensing. Therefore, the nanorods functionalised with 3 aminopropyltriethoxysilane (APTES) were utilized for pH sensing and showed the pH sensitivity of 50.1 mV/pH. APTES is also known to be used as a linker to immobilize biomolecules (such as antibodies) The EIS device with APTES functionalized nanorods was used for the label free detection of prostate specific antigen (PSA) Finally, voltage shifts of 23 mV and 35 mV were observed with PSA concentrations of 1 ng/ml and 100 ng/ml, respectively.", "author_names": [ "Narendra Kumar", "Sujata Senapati", "Satyendra Kumar", "Jitendra Kumar", "Siddhartha Panda" ], "corpus_id": 138071366, "doc_id": "138071366", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Functionalized vertically aligned ZnO nanorods for application in electrolyte insulator semiconductor based pH sensors and label free immuno sensors", "venue": "", "year": 2016 }, { "abstract": "The growth of ZnO nanorods by directly etching Zn foil through a low temperature aqueous method has been demonstrated. The as obtained ZnO nanorod possesses a single crystalline structure. The morphologies of ZnO nanostructures are sensitive to a series of growth parameters. Room temperature photoluminescence property of the as synthesised ZnO nanorods shows a strong ultraviolet emission peak at 379 nm. The present work demonstrates the feasibility of the growth of semiconductor nanorods by directly etching the substrate.", "author_names": [ "Ying Lei", "Jing Wang", "Fengyu Qu", "Hui Li", "Xiang Wu" ], "corpus_id": 94036054, "doc_id": "94036054", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Facile approach to ZnO nanorods by directly etching zinc substrate", "venue": "", "year": 2012 }, { "abstract": "The capability of noble metal nanoparticles (NPs) as efficient charge transfer mediators to stimulate Schottky junction triggered charge flow in multifarious photocatalysis has garnered enormous attention in the past decade. Nevertheless, fine tuning and controllable fabrication of a directional charge transport channel in metal/semiconductor heterostructures via suitable interface engineering is poorly investigated. Here, we report the progressive fabrication of a tailor made directional charge transfer channel in Pt nanoparticles (NPs) inlaid WO3 (Pt WO3) nanocomposites via an efficient electrostatic layer by layer (LbL) self assembly integrated with a thermal reduction treatment, by which oppositely charged metal precursor ions and polyelectrolyte building blocks were intimately and alternately assembled on the WO3 nanorods (NRs) by substantial electrostatic interaction. LbL self assembly buildup and in situ self etching induced structural variation of WO3 NRs to a microsized superstructure occur simultaneously. We found that such exquisitely crafted Pt WO3 nanocomposites exhibit conspicuously enhanced and versatile photoactivities for nonselective mineralizing of organic dye pollution and reduction of heavy metal ions at ambient conditions under both visible and simulated sunlight irradiation, demonstrating a synergistic effect. This is attributed to the imperative contribution of Pt NPs as electron traps to accelerate the directional high efficiency electron transport from WO3 to Pt NPs, surpassing the confinement of electron transfer kinetics of WO3 owing to low conduction level. More intriguingly, photoredox catalysis can also be triggered simultaneously in the same reaction system. The primary in situ produced active species in the photocatalytic reactions were specifically analyzed, and underlying photocatalytic mechanisms were determined. Our work would provide a universal synthesis strategy for constructing various metal decorated semiconductor nanocomposites for widespread photocatalytic utilizations.", "author_names": [ "Huaxiang Lin", "Shuai Xu", "Xiaoguo Fu", "Zhi-quan Wei", "Ming-Hui Huang", "Xin Lin", "Yunhui He", "Guangcan Xiao", "Fang-Xing Xiao" ], "corpus_id": 212564024, "doc_id": "212564024", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Layer by Layer Self Assembly of Metal/Metal Oxide Superstructures: Self Etching Enables Boosted Photoredox Catalysis.", "venue": "Inorganic chemistry", "year": 2020 }, { "abstract": "The physical properties of inorganic nanoparticles (NPs) depend on their shape, size and composition. Noble metal NPs exhibit strong localized surface plasmon resonances (LSPR) in the visible or near IR wavelength range. Hence, metal and semiconductor NPs of different nature have found broad application in imaging and colorimetric bioanalytical assays. Gold nanorods (AuNRs) and fluorescent semiconductor quantum dots (QDs) can be employed as a highly sensitive platform to probe environmental changes through variations in their size. The longitudinal LSPR frequency demonstrated by Au NRs is highly sensitive to minute changes in the AuNR aspect ratio. The emission spectra of spherical QDs depends on their diameter and concentration. We discovered for the first time that the oxidative enzyme Horseradish Peroxidase is able to produce free radicals which oxidize AuNRs and semiconductor QDs. We introduced novel bio analytical assays based on enzymatic etching of inorganic nanoparticles. HRP is able to induce a gradual oxidation of the AuNRs in the presence of trace concentrations of H2O2 and halide ions.[1] As a consequence, other enzymatic reactions, carried out by Glucose Oxidase (GOx) can be easily coupled to the HRP activity assay, thereby allowing for the detection of different amounts of glucose. Modification of AuNRs with thiol containing organic molecules such as glutathione and thiocholine hinders enzymatic etching of AuNR. Higher concentrations of thiol containing molecules in the reaction mixture gradually decrease the rate of enzymatic etching. Interestingly, the decrease in the rate of AuNR shortening can be easily monitored by UV Vis spectroscopy, through changes in the longitudinal LSPR band, highly sensitive to variations in AuNR aspect ratio. This effect can be applied to develop the novel optical assays for acetylcholine esterase (AChE) activity (Figure 1) The biocatalytic hydrolysis of acetylthiocholine by AChE yields thiocholine, which prevents enzymatic AuNR etching in the presence of HRP. 2 We also descovered a facile, mild and inexpensive enzymatic etching method for resizing of CdS QDs. It was found out that the biocatalytic process involving bromide, HRP and H2O2 decreased the size of semiconductor CdS QDs. Thus, this phenomenon can be applied to resizing of semiconductor CdS QDs under mild physiological conditions and rapid and sensitive detection of H2O2 and HRP (Figure 2) It was proven that CdS QDs immobilized on polyvinyl chloride microspheres can be etched biocatalytically too. Thus, we introduced a new platform for optical detection of analytes based on etching of semiconductor NPs. 3 References [1] Saa L, Coronado Puchau M, Pavlov V, Liz Marzan LM, Nanoscale. 6(13) (2014) 7405. [2] Saa L, Grinyte L, Liz Marzan LM, Pavlov V. manuscript in preparation. [3] Grinyte R, Saa L, Garai Ibabe G, Pavlov V, Chem. Commun. 51, (2015),17152.", "author_names": [ "Laura Saa", "Ruta Grynite", "Marc Coronado-Puchaua" ], "corpus_id": 195817309, "doc_id": "195817309", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Enzymatic etching of nonoparticles in biosensing", "venue": "", "year": 2016 }, { "abstract": "Operational stability and sensitivity are key issues in the practical application thin film transistor (TFT) of sensors, and the interdigital electrode is an important element that can be applied to TFT. In this study, a completely transparent interdigital electrode was printed on the glass plated with indium tin oxide (ITO) material using a laser etching machine. The produced interdigital electrode has the characteristics of high density, small line spacing, high sensitivity, and laser etching can be large. The amplitude reduces the production time of the device. Use a semiconductor tester to test the electrical transfer characteristics of the interdigital electrodes. The photoelectric generation spectrum and absorption spectrum of the interdigital electrode array plated with indium gallium zinc oxide (IGZO) material were tested. After plated with IGZO material, the ability to absorb light was greatly enhanced. The interdigital electrodes plated with IGZO material can be applied to the driving and test circuits of flexible wearable spectroscopic industrial detection sensors. It can amplify the circuit signal. After being plated with IGZO material, the power consumption of the circuit can be greatly reduced, and the measurement with low power consumption, high stability and high accuracy can be realized.", "author_names": [ "Zhenwu Tang", "Zhaohai Liu", "Zhi Tao", "Wen-Jian Kuang" ], "corpus_id": 235454429, "doc_id": "235454429", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fully Transparent TFT Sensor Array with IGZO/Nanorods Enhancing Structure", "venue": "2021 IEEE 4th International Conference on Electronics Technology (ICET)", "year": 2021 }, { "abstract": "Single crystalline a Fe2O3 nanorods were prepared by a simple and direct hydrothermal method in large quantities. The 1, 2 propanediamine played the role of shape control agent for the formation of a Fe2O3 nanorods. The characteristics and the evolution mechanism of a Fe2O3 nanorods were investigated in detail. As reaction time prolonged, the hydrogen ions generated by the hydrolysis of Fe3+ could etch the surface of a Fe2O3 nanorods and resulted in the eroded a Fe2O3 nanorods formation. HRTEM results demonstrated that the eroded a Fe2O3 nanorods have rough edges and corners which leading to higher photodegradation ability. Absorption spectra and photocurrent responses indicated that the eroded a Fe2O3 nanorods have a narrow bandgap and higher photocurrent response, which were benefit for absorbing photons and inhibiting the recombination of photogenerated charges. It is expected that the etching of semiconductor materials is an effective way to design the photocatalysts with a high performance, and the a Fe2O3 nanorods with high visible light photocatalytic activity could find potential applications in the field of environmental management.", "author_names": [ "Xiaole Yan", "Yiduo Wu", "Dingding Li", "Jie Hu", "Gang Li", "Pengwei Li", "Huabei Jiang", "Wendong Zhang" ], "corpus_id": 139228033, "doc_id": "139228033", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Synthesis and evolution of a Fe2O3 nanorods for enhanced visible light driven photocatalysis", "venue": "Journal of Materials Science", "year": 2018 }, { "abstract": "GaN/InGaN multiple quantum wells (MQW) is a promising material for high efficiency solid state lighting. Ultrafast optical pump probe spectroscopy is an important characterization technique for examining fundamental phenomena in semiconductor nanostructure with sub picosecond resolution. In this study, ultrafast exciton and charge carrier dynamics in GaN/InGaN MQW planar layer and nanorod are investigated using femtosecond transient absorption (TA) techniques at room temperature. Here nanorods are fabricated by etching the GaN/InGaN MQW planar layers using nanosphere lithography and reactive ion etching. Photoluminescence efficiency of the nanorods have been proved to be much higher than that of the planar layers, but the mechanism of the nanorod structure improvement of PL efficiency is not adequately studied. By comparing the TA profile of the GaN/InGaN MQW planar layers and nanorods, the impact of surface states and nanorods lateral confinement in the ultrafast carrier dynamics of GaN/InGaN MQW is revealed. The nanorod sidewall surface states have a strong influence on the InGaN quantum well carrier dynamics. The ultrafast relaxation processes studied in this GaN/InGaN MQW nanostructure is essential for further optimization of device application.", "author_names": [ "Weijian Chen", "Xiaoming Wen", "Michael Latzel", "Jianfeng Yang", "Shujuan Huang", "Santosh Shrestha", "Robert J Patterson", "Silke H Christiansen", "Gavin Conibeer" ], "corpus_id": 139823603, "doc_id": "139823603", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Ultrafast carrier dynamics in GaN/InGaN multiple quantum wells nanorods", "venue": "Micro Nano Materials, Devices, and Applications", "year": 2018 }, { "abstract": "We report a hybrid solar cell based on well aligned crystalline silicon nanorods (SiNRs) and an organic semiconductor, 2,2',7,7' Tetrakis (N,N di 4 methoxyphenylamino) 9,9' spirobifluorene (Spiro OMeTAD) in a core sheath heterojunction structure. The device is formed by spin coating Spiro OMeTAD on SiNRs array fabricated by electroless chemical etching. A silver grid on a conductive poly (3,4 ethylene dioxythiophene) polystyrenesulfonate layer is used as the top transparent anode. A power conversion efficiency of 10.3% has been obtained for a 1 cm2 cell with 0.35 um long SiNRs. The high efficiency and simple solution process used suggest that such devices are promising for developing low cost and high efficiency SiNRs/organic solar cells.", "author_names": [ "Lining He", "Changyun Jiang", "", "Donny Jiancheng Lai", "Hao Wang" ], "corpus_id": 122300009, "doc_id": "122300009", "n_citations": 97, "n_key_citations": 3, "score": 0, "title": "Highly efficient Si nanorods/organic hybrid core sheath heterojunction solar cells", "venue": "", "year": 2011 } ]

[ { "abstract": "it was demonstrated that an optical switch which was operated at 10 Gbit/s was realized using SOA's in a Mach Zehnder(SOA MZI) configuration, which based on cross phase modulation (XPM) in semiconductor optical amplifier(SOA) and interference struct. An analysis was presented to describe the phase changing in SOA, which caused by optical power injected into S OA. The interference struct supplied a method to transform phase shift into amplitude. At this process, the switch window would been created. Through the simulation the switch was approved.", "author_names": [ "Ya lin Guan", "Rui-dong Wang" ], "corpus_id": 119759985, "doc_id": "119759985", "n_citations": 12, "n_key_citations": 0, "score": 1, "title": "Demonstration of an optical switch based on SOA MZI operation at 10 Gbit/s", "venue": "", "year": 2013 }, { "abstract": "In this paper, the semiconductor optical amplifier (SOA) is used with a Mach Zehnder interferometer (MZI) forming an SOA MZI structure which is used to perform the logic gates OR, and NOT. It is simulated at 10 Gbps, 20 Gbps, and 40 Gbps to extract simple design rules. Two binary input data signals are simulated at several bitrate 10 Gbps, 20 Gbps, and 40 Gbps. It is demonstrated that high data rate can be achieved with a specific injection current in SOA. SOAs required low injection current, which leads to a low value on the total power consumption of the gate. In addition, this work includes the study of the effect of the bit rate on the received power, minimum bit error rate (BER) and maximum quality factor (Q factor) The logical output of the gate has an extinction ratio of more than 10 dB with good eye opening. The output of the OR, NOT gates shows error free operation at different bit rate with a clear eye opening. General Terms Optical amplifier, MZI, optical logic gates.", "author_names": [ "Azhar Hussein", "Ismael Shanan" ], "corpus_id": 53442802, "doc_id": "53442802", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High Data Rate Optical logic OR, and NOT Gates at Optimum Injection Current based on SOA MZI", "venue": "", "year": 2017 }, { "abstract": "We experimentally demonstrate on chip all optical wavelength conversion (AOWC) of four level pulse amplitude modulation (PAM 4) signals by cross gain modulation in an InP monolithically integrated turbo switch circuit based on semiconductor optical amplifiers (SOAs) Full characterization of the photonic integrated circuit (PIC) is given, where sevenfold reduction in effective gain recovery is achieved by the PIC turbo switch compared with a case of single SOA switch. Wavelength conversion of 25 Gbit/s PAM 4 signal in the C band is successfully demonstrated with ~2 dB power penalty at 1 x 10 3 bit error rate. Moreover, the wavelength dependence of the converter is studied. The integrated AOWC device has the advantages of high speed switching operation as well as small footprint, high stability, and low switching power.", "author_names": [ "Adnan A E Hajomer", "Marco Presi", "Nicola Andriolli", "Claudio Porzi", "Weisheng Hu", "Giampiero Contestabile", "Xuelin Yang" ], "corpus_id": 191137555, "doc_id": "191137555", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "On Chip All Optical Wavelength Conversion of PAM 4 Signals Using an Integrated SOA Based Turbo Switch Circuit", "venue": "Journal of Lightwave Technology", "year": 2019 }, { "abstract": "in this paper, a Kerr tunable all optical switch is presented which works in photonic crystal platform and implement octagonal shape ring resonator(s) for enhancing the level of nonlinear light amplitude required for the device operation. Two switches are designed and compared; one based on a single (SR) and the other based on a double vertically (DR) aligned ring resonators. Silicon (Si) nanocrystal is used as the driving material for the nonlinear parts. Since the transmission spectra of the DR switch has a higher Q factor rather than SR and also since the optical power reads more nonlinear rods within the DR, thus the optical power required is much lower (at least 10 folds) than the SR switch. The required time for DR switch to change its state from on to off is computed to be less than 10ps, at l0=1552nm. The minimum power required to turn DR switch state on/off is less than 6mW/mm. Performance of the switch is simulated by means of finite difference time domain (FDTD) method, which confirmed the ultra compact sized for the structure working with an ultrafast speed.", "author_names": [ "Alireza Tavousi", "Mehdi Saffari", "Mohammad Ali Mansouri-Birjandi" ], "corpus_id": 53983070, "doc_id": "53983070", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Proposal for a Kerr Tunable All Optical Switch Based on Photonic Crystal Ring Resonators", "venue": "", "year": 2018 }, { "abstract": "At the dawning of the exaflop era, High Performance Computers are foreseen to exploit integrated all optical elements, to overcome the speed limitations imposed by electronic counterparts. Drawing from the well known Memory Wall limitation, imposing a performance gap between processor and memory speeds, research has focused on developing ultra fast latching devices and all optical memory elements capable of delivering buffering and switching functionalities at unprecedented bit rates. Following the master slave configuration of electronic Flip Flops, coupled SOA MZI based switches have been theoretically investigated to exceed 40 Gb/s operation, provided a short coupling waveguide. However, this flip flop architecture has been only hybridly integrated with silica on silicon integration technology exhibiting a total footprint of 45x12 mm2 and intra Flip Flop coupling waveguide of 2.5cm, limited at 5 Gb/s operation. Monolithic integration offers the possibility to fabricate multiple active and passive photonic components on a single chip at a close proximity towards, bearing promises for fast all optical memories. Here, we present for the first time a monolithically integrated all optical SR Flip Flop with coupled master slave SOA MZI switches. The photonic chip is integrated on a 6x2 mm2 die as a part of a multi project wafer run using library based components of a generic InP platform, fiber pigtailed and fully packaged on a temperature controlled ceramic submount module with electrical contacts. The intra Flip Flop coupling waveguide is 5 mm long, reducing the total footprint by two orders of magnitude. Successful flip flop functionality is evaluated at 10 Gb/s with clear open eye diagram, achieving error free operation with a power penalty of 4dB.", "author_names": [ "Stelios Pitris", "Christos Vagionas", "George T Kanellos", "Rifat Kisacik", "Tolga Tekin", "Ronald Broeke", "Nikos Pleros" ], "corpus_id": 124997711, "doc_id": "124997711", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "All optical SR flip flop based on SOA MZI switches monolithically integrated on a generic InP platform", "venue": "SPIE OPTO", "year": 2016 }, { "abstract": "We report on the first timescale based entirely on optical technology. Existing timescales, including those incorporating optical frequency standards, rely exclusively on microwave local oscillators owing to the lack of an optical oscillator with the required frequency predictability and stability for reliable steering. We combine a cryogenic silicon cavity exhibiting improved long term stability and an accurate {87}Sr lattice clock to form a timescale that outperforms them all. Our timescale accumulates an estimated time error of only 48+ 94 ps over 34 days of operation. Our analysis indicates that this timescale is capable of reaching a stability below 1x10^ 17} after a few months of averaging, making timekeeping at the 10^ 18} level a realistic prospect.", "author_names": [ "William R Milner", "John M Robinson", "Colin J Kennedy", "Tobias Bothwell", "Dhruv Kedar", "Dan G Matei", "Thomas Legero", "Uwe Sterr", "Fritz Riehle", "Holly Leopardi", "Tara M Fortier", "Jeff A Sherman", "Judah Levine", "Jian Yao", "Jun Ye", "Eric Oelker" ], "corpus_id": 195833739, "doc_id": "195833739", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Demonstration of a Timescale Based on a Stable Optical Carrier.", "venue": "Physical review letters", "year": 2019 }, { "abstract": "We present a new forwarding gate scheme using a single SOA MZI. We show a bi stable behavior with a 13.6 dB extinction ratio and rise and fall times below 30ps. Error free operation is achieved at 40 Gb/s.", "author_names": [ "Houssem Brahmi", "Marios Bougioukos", "Mourad Menif", "Alexandros Maziotis", "Chronis Stamatiadis", "Ch Kouloumentas", "Dimitrios Apostolopoulos", "Hercules Avramopoulos", "Didier Erasme" ], "corpus_id": 42724414, "doc_id": "42724414", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Experimental demonstration of an all optical packet forwarding gate based on a single SOA MZI at 40 Gb/s", "venue": "2011 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference", "year": 2011 }, { "abstract": "We investigated the feasibility of using an optical divider circuit with a semiconductor optical amplifier Mach Zehnder interferometer (SOA MZI) based exclusive or (XOR) gate for an all optical forward error detection and correction scheme with a cyclic code. We employed a conventional cyclic code scheme: the same divider circuit acts as both encoder and decoder with a given generator polynomial. The divider circuit consists of cascaded XOR circuits and feedback lines. Therefore, the performance of the XOR circuit is one of the key factors for realizing an all optical scheme. We numerically investigated the operation performance of the SOA MZI based all optical XOR gate. Dynamic operation was simulated using rate equations via the transfer matrix method. The XOR function was also investigated experimentally. The eye diagram obtained from the simulation at a bit rate of 10 Gb/s showed good qualitative agreement with experimental results. Additionally, we confirmed that the optimal condition for a high quality factor (Q factor) is obtained with equal power for each signal. Next, we demonstrated all optical divider processing with the SOA MZI based XOR circuit and a feedback line that forms the generator polynomial x 1. The preliminary results for division operation could be verified.", "author_names": [ "Yohei Aikawa", "Satoshi Shimizu", "Hiroyuki Uenohara" ], "corpus_id": 36764908, "doc_id": "36764908", "n_citations": 45, "n_key_citations": 0, "score": 0, "title": "Demonstration of All Optical Divider Circuit Using SOA MZI Type xor Gate and Feedback Loop for Forward Error Detection", "venue": "Journal of Lightwave Technology", "year": 2011 }, { "abstract": "On chip all optical wavelength conversion of 56 Gbit/s non return to zero signals in an integrated SOA based turbo switch is demonstrated. A power penalty of 2.6 dB (5 dB) at BER of 10 6 is achieved for down (up conversion.", "author_names": [ "Adnan A E Hajomer", "Francesca Bontempi", "Nicola Andriolli", "Claudio Porzi", "W Hu", "X Yang", "Giampiero Contcstabile" ], "corpus_id": 201812647, "doc_id": "201812647", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "56 Gb/s All Optical Wavelength Conversion based on a Photonic Integrated Turbo Switch", "venue": "2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC)", "year": 2019 }, { "abstract": "In this paper, we demonstrated an optical D type flip flop based on the electro optic switching effect of silicon microring resonator. The operation of the flip flop has been verified by simulation using a clock signal of 10 Gbps and data signal of 1 Gbps. The results of the proposed flip flop have been presented by the timing diagrams.", "author_names": [ "Law Foo Kui", "M Rakib Uddin" ], "corpus_id": 4337945, "doc_id": "4337945", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Demonstration of digital optical D flip flop based on photonic micro ring resonator", "venue": "2018 20th International Conference on Advanced Communication Technology (ICACT)", "year": 2018 } ]

[ { "abstract": "We studied the structural, electronic, and optical characters of SiS2, a new type of group IV VI two dimensional semiconductor, in this article. We focused on monolayer SiS2 and its characteristic changes when different strains are applied on it. Results reveal that the monolayer SiS2 is dynamically stable when no strain is applied. In terms of electronic properties, it remains a semiconductor under applied strain within the range from 10% to 10% Besides, its indirect band gap is altered regularly after applying a strain, whereas different strains lead to various changing trends. As for its optical properties, it exhibits remarkable transparency for infrared and most visible light. Its main absorption and reflection regions lie in the blue and ultraviolet areas. The applied uniaxial strain causes its different optical properties along the armchair direction and zigzag direction. Moreover, the tensile strain could tune its optical properties more effectively than the compressive strain. When different strains are applied, the major changes are in blue and ultraviolet regions, but only minor changes can be found in infrared and visible regions. So its optical properties reveal good stability in infrared and visible regions. Therefore, SiS2 has a promising prospect in nano electronic and nano photoelectric devices.", "author_names": [ "Qingyuan Chen", "Ming-yang Liu", "Chao Cao", "Yao He" ], "corpus_id": 232091943, "doc_id": "232091943", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Strain dependent optical properties of the novel monolayer group IV dichalcogenides SiS2 semiconductor: a first principles study", "venue": "Nanotechnology", "year": 2021 }, { "abstract": "Motivated by the recent synthesis of layered hexagonal aluminum nitride $h$ AlN) we investigate its layer and strain dependent electronic and optical properties by using first principles methods. Monolayer $h$ AlN is a wide gap semiconductor, which makes it interesting especially for usage in optoelectronic applications. The optical spectra of 1 2 3 and 4 layered $h$ AlN indicate that the prominent absorption takes place outside the visible light regime. Within the ultraviolet range, absorption intensities increase with the number of layers, approaching the bulk case. On the other hand, the applied tensile strain gradually redshifts the optical spectra. The many body effects lead to a blueshift of the optical spectra, while exciton binding is also observed for 2D $h$ AlN. The possibility of tuning the optoelectronic properties via thickness and/or strain opens doors to novel technological applications of this promising material.", "author_names": [ "D Kecik", "Cihan Bacaksiz", "R T Senger", "Engin Durgun" ], "corpus_id": 44139432, "doc_id": "44139432", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Layer and strain dependent optoelectronic properties of hexagonal AlN", "venue": "", "year": 2015 }, { "abstract": "The search for new two dimensional (2D) materials with novel optical and electronic properties is always desirable for material development. Herein, we report a comprehensive theoretical prediction of 2D SiC compounds with different stoichiometries from C rich to Si rich. In addition to the previously known hexagonal SiC sheet, we identified two types of hitherto unknown structural motifs with distinctive bonding features. The first type of 2D SiC monolayer, including t SiC and t Si2C sheet, can be described by tetragonal lattice. Among them, t SiC monolayer sheet is featured by each carbon atom binding with four neighboring silicon atoms in almost the same plane, constituting a quasi planar four coordinated rectangular moiety. More interestingly, our calculations demonstrate that this structure exhibits a strain dependent insulator semimetal transition, suggesting promising applications in strain dependent optoelectronic sensors. The second type of 2D SiC sheet is featured by silagraphyne with acetylenic linkages CC Silagraphyne shows both high pore sizes and Poisson's ratio. These properties make it a potentially important material for applications in separation membranes and catalysis. Moreover, one of the proposed structures, g silagraphyne, is a direct band gap semiconductor with a bandgap of 0.89 eV, which has a strong absorption peak in the visible light region, giving a promising application in ultra thin transistors, optical sensor devices and solar cell devices.", "author_names": [ "Dong Fan", "Shaohua Lu", "Yundong Guo", "Xiaojun Hu" ], "corpus_id": 119336127, "doc_id": "119336127", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Novel bonding patterns and optoelectronic properties of the two dimensional SixCy monolayers", "venue": "", "year": 2016 }, { "abstract": "Since their discovery, single layer semiconducting transition metal dichalcogenides have attracted much attention, thanks to their outstanding optical and mechanical properties. Strain engineering in these two dimensional materials aims to tune their bandgap energy and to modify their optoelectronic properties by the application of external strain. In this paper, we demonstrate that biaxial strain, both tensile and compressive, can be applied and released in a timescale of a few seconds in a reproducible way on transition metal dichalcogenides monolayers deposited on polymeric substrates. We can control the amount of biaxial strain applied by letting the substrate expand or compress. To do this, we change the substrate temperature and choose materials with a large thermal expansion coefficient. After the investigation of the substrate dependent strain transfer, we performed micro differential spectroscopy of four transition metal dichalcogenides monolayers (MoS2, MoSe2, WS2, WSe2) under the application of biaxial strain and measured their optical properties. For tensile strain, we observe a redshift of the bandgap that reaches a value as large as 95 meV/ in the case of single layer WS2 deposited on polypropylene. The observed bandgap shifts as a function of substrate extension/compression follow the order MoSe2 MoS2 WSe2 WS2. Theoretical calculations of these four materials under biaxial strain predict the same trend for the material dependent rates of the shift and reproduce well the features observed in the measured reflectance spectra.Strain engineering: Tuning the bandgap of 2D materialsThe bandgap of two dimensional semiconducting materials can be easily tuned in real time by stretching or compressing them. An international team of researcher led by Dr. Andres Castellanos Gomez at IMDEA Nanoscience, Spain, studied the optical properties of single atom thick two dimensional semiconductors under the application of tensile or compressive biaxial strain. In order to apply the strain the researchers exploited the thermal expansion or compression of the different substrates carrying the atomically thin materials and then compared their results to atomistic simulations. This strain method can be applied in a fast and reversible way and it leads to large changes in the band structure of these semiconducting materials. Research into strain engineering two dimensional materials may help us in fabricating novel devices like color changing light emitters or novel and more efficient solar cells.", "author_names": [ "Riccardo Frisenda", "Matthias Druppel", "Robert Schmidt", "Steffen Michaelis de Vasconcellos", "David Perez De Lara", "Rudolf Bratschitsch", "Michael Rohlfing", "Andres Castellanos-Gomez" ], "corpus_id": 119330658, "doc_id": "119330658", "n_citations": 98, "n_key_citations": 1, "score": 0, "title": "Biaxial strain tuning of the optical properties of single layer transition metal dichalcogenides", "venue": "npj 2D Materials and Applications", "year": 2017 }, { "abstract": "We describe a facile technique based on polymer encapsulation to apply several percent controllable strains to monolayer and few layer Transition Metal Dichalcogenides (TMDs) We use this technique to study the lattice response to strain via polarized Raman spectroscopy in monolayer WSe2 and WS2. The application of strain causes mode dependent redshifts, with larger shift rates observed for in plane modes. We observe a splitting of the degeneracy of the in plane E modes in both materials and measure the Gruneisen parameters. At large strain, we observe that the reduction of crystal symmetry can lead to a change in the polarization response of the A mode in WS2. While both WSe2 and WS2 exhibit similar qualitative changes in the phonon structure with strain, we observe much larger changes in mode positions and intensities with strain in WS2. These differences can be explained simply by the degree of iconicity of the metal chalcogen bond. One of the iconic characteristics of monolayer 2D materials is their incredible stretchability which allows them to be subjected to several percent strain before yielding [1] The application of moderate ~1% strains is expected to change the anharmonicity of interatomic potentials [2, 3] phonon frequencies [4, 5] and effective masses [6, 7] At larger strains, topological electronic[8] [9] and semiconductor metal structural phase changes have been predicted [10 13] Important technological applications such as piezoelectricity can be explored by the application of systematic strain [14, 15] One of the chief problems in achieving reproducible strain is the intrinsic nature of 2D materials as single layer sheets they need to be held to a flexible substrate which is then stretched or compressed. Previous experiments [16 19] have used flexible polymers as substrates and metal or polymer caps in order to constrain the 2D material. Using these techniques, approximate strains up to 4% have been reported so far in the literature, but independent verification of the applied strain has been lacking. Achieving large reproducible strains in engineered geometries will allow us to probe these exciting properties of individual 2D materials and their heterostructures [4, 17, 20 26] In this work, we develop a new strain platform to apply large range accurate uniaxial tensile strains on monolayer and fewlayer materials. One of our chief innovations is the development of a novel polymer based encapsulation method to enable the application of large strain to 2D materials. Here, we apply this technique to study the strain dependent properties of monolayer WSe2 and WS2 grown by Chemical Vapor Deposition (CVD) on SiO2/Si substrates [27 29] We use cellulose acetate butyrate (CAB) to lift the monolayers from the SiO2/Si substrates and transfer to polycarbonate substrates. The two polymers are then bonded to produce encapsulated monolayers and multilayers. The key to achieving good bonding is perfect control over the temperature, time and pressure during the bonding process. Additionally, polymer layers that are in the amorphous phase cause nonlinear strain deflection behavior which is not desirable in our experiments. To resolve this issue, we crystallize the polymer stacks by annealing near the glass transition temperature followed by slow cooling. The crystallized polymers are fully flexible, elastic and springy substrates as shown in Fig. 1(a) After all of our processing steps, we find that the polymer stacks enter into the plastic regime at 7% strain. We find that strains up to this value are perfectly transferred to the encapsulated 2D material as described below. Our strain method adopts the extra neutral axis bending technique Fig. 1(b) in which areas above the neutral axis undergo tensile strain while those below the axis experience compressive strain. In our method, we use a screw driven vertical translation stage to apply strain to the polymer stacks. We solve the Euler Bernoulli equation for our geometry in order to achieve an accurate relation between the vertical displacement d of the translation stage and the strain e of the 2D material. For a fully isotropic, linear and elastic material, the strain displacement relation is derived as: e 3td a(3b 2a) where t is the substrate thickness, b and a are center support and cantilever lengths respectively. In our experiments, the use of a fine adjustment screw gives us a resolution of 0.05% strain for 0.5 mm substrates, with essentially no limit to the maximum strain that can be applied. More details are provided in the Supplemental Material. Shown in Fig. 1(c) is an optical image of triangular flakes of WSe2 encapsulated by this process. We adjust the CVD process to produce triangular flakes in order to easily identify the crystallographic directions of the grown monolayers. Since the strains achievable in our experiments are large, we can directly verify from optical measurements that the strain being applied to 2D layer is the calculated value. This is illustrated in Fig. 1(d) Each of these images is obtained by overlaying two images, one at zero strain and one at a fixed value of strain (4.2% and 6.5% respectively) Only the edges of the triangles are shown in the images, which are lined up to be at the same vertical height at the top vertex of the triangle. We can directly see by inspection that the length of the triangle along the strain direction is larger when strained as one expects. A pixel height measurement of the edge detected images gives us a direct experimental measure of the applied strain, which can be compared to the calculated strain based on the screw displacement. It is found that the two measurements match within 0.1% absolute strain. Thus, our technique allows for the application of uniform, highly repeatable and independently measurable strain on TMD monolayers and heterostructures. In order to probe the effects of strain on our samples, we choose to characterize with Raman spectroscopy a simple yet powerful way to measure lattice properties and their coupling to the electronic degrees of freedom. Strains were applied in both zigzag and armchair directions (Y and X axes in Fig. 1(e) in our experiments. Our Raman setup with 532 nm excitation wavelength is shown in Fig. 1(f) The measurements were performed while controlling for the incident light's polarization (Ei) direction (th in Fig. 1(e) For each experiment, Raman spectra were collected in both the parallel(Es Ei) and crosspolarized (Es Ei) detector geometries, shown with standard notations Z(YY)Z and Z(YX)Z respectively. In our experiments, we found no dependence of the Raman spectra on the angle of incidence relative to the crystallographic axis at zero strain. We therefore fix our incidence angle to the Y direction, and measure the unpolarized, parallel polarized and cross polarized Raman spectra at each value of strain which is applied in the X direction. We first discuss the properties of monolayer WSe2. Shown in Fig. 2(a) are a sequence of spectra taken at different values of strain in the unpolarized, parallel and cross polarization geometries. Previous Raman spectroscopy measurements performed on monolayer WSe2 have identified three vibrational modes [30 32] termed A, E and 2LA. A is an out of plane phonon mode in which the top and bottom chalcogen atoms vibrate in opposing directions; while E is in plane mode where the metal atoms vibrate out of phase with the chalcogen atoms [33] The 2LA mode results from a double resonance process involving two phonons from the LA branch. Second order processes can in general give rise to a complex lineshape in the Raman spectrum; yet, in the case of WSe2 we find that a single Lorentzian can be used to model well the 2LA mode lineshape. Although Aand E modes are nearly degenerate, they can be distinguished from each other by polarization dependency of their intensities. The out of plane, symmetric A mode disappears due to its symmetry in the cross polarization geometry, leaving behind only the E mode. Our spectra in the cross polarization geometry can thus be modeled well as the sum of two Lorentzian peaks corresponding to E and 2LA modes. Information of the E mode position can then be used to fit the spectra seen in the parallel polarization geometry in order to extract the nearlyoverlapping A mode position. Having understood the polarization dependent Raman spectra of unstrained monolayer WSe2, we apply uniaxial strains and measure the Raman response. The effects of uniaxial strain up to 1% on monolayer WSe2 has previously been experimentally investigated via unpolarized Raman [17] and absorption spectroscopy [34] Raman spectra under increasing uniaxial strain up to 3% are shown in Fig. 2(a) A close examination of spectral lineshapes in the cross polarization geometry shows that the E mode becomes broader with increasing strain. In general, we expect that the initially doubly degenerate E mode splits on the application of strain into E and E. The displacement eigenvector of the E mode is orthogonal to the direction of strain, while it is parallel for the Emode, as has previously been observed for MoS2 and graphene [3, 16, 21] While we cannot observe a complete separation of the E and E modes in our data, it is nevertheless straightforward to fit the lineshape to two Lorentzian functions and extract the splitting as a function of strain, as shown in Fig. 2(e) The splitting of the E mode under tensile strain due to the anharmonictiy of molecular potentials can be described by Gruneisen parameter g |oE' |oE' 2oE'(1 v) and the shear deformation potential b |oE' |oE' 2oE'(1 v) where oE' is the frequency of E mode, oE' and oE' are the frequency shifts of split modes per unit percent strain and v is Poisson's ratio which is 0.27 for our substrates. We obtain values of g 0.38 b 0.10 for WSe2 which are smaller than those reported for graphene [2, 3] Using t", "author_names": [ "Abdollah Motmaen Dadgar", "Declan Scullion", "Kyung Nam Kang", "Daniel V Esposito", "Eui-Hyeok Yang", "Irving P Herman", "Marcos A Pimenta", "Elton J G Santos", "Abhay N Pasupathy" ], "corpus_id": 39369533, "doc_id": "39369533", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Achieving Large, Tunable Strain in Monolayer Transition Metal Dichalcogenides", "venue": "", "year": 2017 }, { "abstract": "Strain engineering is an effective way to tune the thermal and electrical properties of novel two dimensional (2D) materials. In this work, first principles density functional theory (DFT) is used to systematically investigate the strain dependent lattice thermal conductivity and phonon properties of buckled arsenene and phosphorene, which are the 2D materials with the highest thermal conductivities among monolayers in group VA. We implemented an iterative self consistent solution to the Peierls Boltzmann transport equation (PBTE) Our results showed that the thermal conductivity in both monolayers exhibits an up and down behavior when biaxial tensile strain is applied in the range from 0% to 9% The peak values in the thermal conductivities occur at 5% of strain in arsenene and 3% in phosphorene, with the maximum conductivities of strained arsenene and phosphorene being 1.4 and 1.2 times higher than those of unstrained samples, respectively. We provide a rigorous description of the underlying phonon physics responsible for these thermal responses to strain, addressing the interplay between phonon group velocities, heat capacities, and relaxation times. The acoustic optical phonon band gaps in arsenene and phosphorene were found to reduce with strain, being the reduction more significant in phosphorene. Our results also showed that the use of the single mode relaxation time approximation (SMRTA) predict substantially lower thermal conductivities for arsenene and phosphorene than those predicted by the iterative solution of the PBTE.", "author_names": [ "Armin Taheri", "Carlos da Silva", "Cristina H Amon" ], "corpus_id": 53096428, "doc_id": "53096428", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Effects of biaxial tensile strain on the first principles driven thermal conductivity of buckled arsenene and phosphorene.", "venue": "Physical chemistry chemical physics PCCP", "year": 2018 }, { "abstract": "[Synthesis and Terahertz Applications of Large Area Monolayer Graphene] by Minjie Wang Monolayer graphene, successfully isolated in 2004 for the first time, is the first member of the class of materials called two dimensional (2D) materials. It consists of a 2D honeycomb lattice of sp2 bonded carbon atoms, possessing extraordinary mechanical, chemical, and physical properties. The unique band structure and gate tunability of graphene are expected to result in novel highfrequency (THz) and optical phenomena. In this thesis work, we used two different ways to grow graphene on a copper foil via chemical vapor deposition (CVD) One method synthesized continuous, large size monolayer graphene, while the other method created signalcrystal graphene with no domain boundaries. We transferred grown graphene from copper foil to SiO2/Si substrates by the wet etch method with four types of copper etchants that are commonly used by researcher: HNO3, FeCl3, (NH4)2S2O8, and a commercial copper etchant. Further tests and analysis showed that the commercial copper etchant is the best for transfer purposes from the perspective of structural integrity, amount of residues, and doping carrier concentration. We conducted strain dependent THz transmission measurements of graphene on a polyimide substrate (Kapton) using a strain controllable mechanicaloptical testing system. Experimental results showed that THz transmittance of graphene changes significantly with strain up to ~30% but no reversible change of THz transmittance was observed. On the other hand, by using a recently proposed total internal reflection (TIR) geometry, we demonstrated significant enhancement of THz wave absorption in monolayer graphene. Our scheme allowed the incident THz beam to be reflected by graphene four times at varying incidence angles, both below and above the critical angle for TIR. We observed extremely large THz absorption, especially for spolarized radiation. The experimental results are quantitatively consistent with our calculations, incorporating realistic values of carrier scattering time and Fermi energy.", "author_names": [ "Minjie Wang" ], "corpus_id": 139400008, "doc_id": "139400008", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Synthesis and Terahertz Applications of Large Area Monolayer Graphene", "venue": "", "year": 2016 }, { "abstract": "We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi LAT to cover the g ray range from 0.1 GeV to 20 TeV; RXTE and Swift to cover wavelengths from UV tohard X rays; and GASP WEBT, which provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St. Petersburg observatories. We evaluate the variability of the source and interband correlations, the g ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self Compton (SSC) scenarios. Aims. The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model to data agreement in the individual model parameters, hence providing a less biased interpretation than the \"single curve SSC model adjustment\" typically reported in the literature. Methods. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid scan shows that the flaring activity around May 22 cannot be modeled adequately with a one zone SSC scenario (using an electron energy distribution with two breaks) while it can be suitably described within a two (independent) zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5 month observing period, while the other one, which is spatially separated from the first, dominates the flaring emission occurring at X rays and very high energy >100 GeV, VHE) g rays. The flaring activity from May 1, which coincides with a rotation of the electric vector polarization angle (EVPA) cannot be satisfactorily reproduced by either a one zone or a two independent zone SSC model, yet this is partially affected by the lack of strictly simultaneous observations and the presence of large flux changes on sub hour timescales (detected at VHE g rays) Results. The higher variability in the VHE emission and lack of correlation with the X ray emission indicate that, at least during the 4.5 month observing campaign in 2009, the highest energy (and most variable) electrons that are responsible for the VHE g rays do not make a dominant contribution to the ~1 keV emission. Alternatively, there could be a very variable component contributing to the VHE g ray emission in addition to that coming from the SSC scenario. The studies with our dedicated SSC grid scan show that there is some degeneracy in both the one zone and the two zone SSC scenarios probed, with several combinations of model parameters yielding a similar model to data agreement, and some parameters better constrained than others. The observed g ray flaring activity, with the EVPA rotation coincident with the first g ray flare, resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties.", "author_names": [ "M L Ahnen", "Stefano Ansoldi", "Lucio Angelo Antonelli", "P Antoranz", "A Babic", "B Banerjee", "Priyadarshini Bangale", "Ulisses Barres DE Almeida", "J A Barrio", "J Becerra Gonz'alez", "W Bednarek", "Elisa Bernardini", "Alessio Berti", "Barbara Biasuzzi", "Adrian Biland", "O Blanch", "S Bonnefoy", "G Bonnoli", "F Borracci", "Thomas Bretz", "Sara Buson", "Alessandro Carosi", "Arka Chatterjee", "R Clavero", "Pierre Colin", "E Colombo", "Jose Luis Contreras", "J Cortina", "Stefano Covino", "Paolo Da Vela", "Francesco Dazzi", "Alessandro De Angelis", "Barbara De Lotto", "Emma de Ona Wilhelmi", "Federico Di Pierro", "Marlene Doert", "Alberto Dom'inguez", "D Dominis Prester", "Daniela Dorner", "Michele Doro", "Sabrina Einecke", "D Glawion", "D Elsaesser", "M Engelkemeier", "Vandad Fallah Ramazani", "A Fern'andez-Barral", "David Carreto Fidalgo", "M V Fonseca", "L Font", "Katharina Frantzen", "Christian Fruck", "D Morachis Galindo", "R J Garc'ia L'opez", "M Garczarczyk", "D Garrido Terrats", "Markus Gaug", "Paola Giammaria", "Nikola Godinovi'c", "Adiv Gonzalez Munoz", "Dariusz Gora", "Daniel A Guberman", "D Hadasch", "A Hahn", "Yoshitaka Hanabata", "Masaaki Hayashida", "J Herrera", "Juergen Hose", "D Hrupec", "Gareth Hughes", "W Idec", "Kazuhito Kodani", "Yusuke Konno", "H Kubo", "J Kushida", "Antonio La Barbera", "D Lelas", "E Lindfors", "S Lombardi", "Francesco Longo", "M A L'opez", "Rub'en L'opez-Coto", "P Majumdar", "M Makariev", "K Mallot", "Galina Maneva", "Marina Manganaro", "Karl Mannheim", "Laura Maraschi", "Benito Marcote", "Mose Mariotti", "M C Mart'inez", "D Mazin", "Uta Menzel", "J M Miranda", "R Mirzoyan", "A Moralejo", "E Moretti", "Daisuke Nakajima", "V V Neustroev", "Andrzej Niedzwiecki", "M Nievas Rosillo", "K Nilsson", "K Nishijima", "K Noda", "L Nogu'es", "A -K Overkemping", "Simona Paiano", "Joaquim Palacio", "M Palatiello", "D Paneque", "Riccardo Paoletti", "Josep Maria Paredes", "Xavier Paredes-Fortuny", "Giovanna Pedaletti", "Michele Peresano", "Luca Perri", "Massimo Persic", "Juri Poutanen", "P G Prada Moroni", "E Prandini", "I Puljak", "Ignasi Reichardt", "Wolfgang Rhode", "Marc Rib'o", "J Rico", "J Rodriguez Garcia", "T Saito", "Konstancja Satalecka", "S Schroder", "Cornelia Schultz", "Thomas Schweizer", "Steven N Shore", "Aimo K Sillanpaa", "J Sitarek", "Iva Snidaric", "D Sobczynska", "A Stamerra", "T Steinbring", "Marcel Strzys", "T Suri'c", "Leo O Takalo", "Fabrizio Tavecchio", "P Temnikov", "Tomislav Terzi'c", "Diego Tescaro", "Masahiro Teshima", "Julia Thaele", "Diego F Torres", "Takeshi Toyama", "Aldo Treves", "G Vanzo", "V Verguilov", "I Vovk", "John E Ward", "Martin Will", "M H Wu", "Roberta Zanin", "Anushka Udara Abeysekara", "Simon Archambault", "Avery Archer", "W Benbow", "R Bird", "M Buchovecky", "James Henry Buckley", "Viatcheslav Bugaev", "Michael P Connolly", "Wei Wei Cui", "Hugh Dickinson", "Abraham D Falcone", "Qi Feng", "John Park Finley", "H Fleischhack", "A Flinders", "Lucy Fortson", "G H Gillanders", "Sean Griffin", "Jeff Grube", "Moritz Hutten", "David Hanna", "Jamie Holder", "Thomas Brian Humensky", "Philip Kaaret", "Payel Kar", "Nathan C Kelley-Hoskins", "M P Kertzman", "D Kieda", "M Krause", "Frank Krennrich", "M J Lang", "Gernot Maier", "Andrew McCann", "Patrick J Moriarty", "Reshmi Mukherjee", "Daniel Nieto", "Stephan O'Brien", "R A Ong", "N Otte", "Nahee Park", "Jeremy S Perkins", "Ana Pichel", "Martin Pohl", "Alexis Popkow", "E Pueschel", "Joseph F Quinn", "K Ragan", "Philip T Reynolds", "Gordon T Richards", "E Roache", "Adrian C Rovero", "Cameron B Rulten", "Iftach H Sadeh", "M Santander", "Glenn H Sembroski", "K Shahinyan", "Igor Telezhinsky", "J V Tucci", "Joshua Tyler", "Scott Patrick Wakely", "A Weinstein", "P Wilcox", "Alina Wilhelm", "D A Williams", "Benjamin Zitzer", "Stefano Villata", "C M Raiteri", "Hugh D Aller", "M F Aller", "V M Larionov", "A Arkharov", "Dmitry Blinov", "Natalia V Efimova", "Tatiana S Grishina", "Vladimir A Hagen-Thorn", "Evgenia N Kopatskaya", "Liudmilla V Larionova", "Elena G Larionova", "Daria A Morozova", "Ivan S Troitsky", "Rolando Ligustri", "Paolo Calcidese", "Andrei V Berdyugin", "O M Kurtanidze", "M G Nikolashvili", "Givi N Kimeridze", "Lorand A Sigua", "S O Kurtanidze", "Revaz Chigladze", "W P Chen", "Ekaterina Koptelova", "Takanori Sakamoto", "Alberto Carlo Sadun", "J Ward Moody", "Cameron J Pace", "Richard L Pearson", "Yoichi Yatsu", "Y A Mori", "A Carraminyana", "Luis Carrasco", "E De la Fuente", "Jay Norris", "P Smith", "Ann Elizabeth Wehrle", "Mark A Gurwell", "Alma C Zook", "Claudio Pagani", "Matteo Perri", "M Capalbi", "Andrea Cesarini", "H A Krimm", "Y Y Kovalev", "Yu A Kovalev", "Eduardo Ros", "A B Pushkarev", "M L Lister", "Kirill V Sokolovsky", "Matthias Kadler", "Glenn Piner", "Anne Lahteenmaki", "Merja Tornikoski", "Emmanouil Angelakis", "Thomas P Krichbaum", "Ioannis Nestoras", "Lars Fuhrmann", "J Anton Zensus", "Pietro Cassaro", "Andrea Orlati", "Giuseppe Maccaferri", "P Leto", "Marcello Giroletti", "Joseph L Richards", "W Max-Moerbeck", "Applied Biosciences Eth Zurich", "", "Universita' di Udine", "Infn Trieste", "Inaf - National Institute for Astrophysics", "Universit'a di Siena", "Infn sez di Pisa", "Croatian Magic Consortium", "Rudjer Boskovic Institute", "University of Rijeka", "University of Split", "University of Zagreb", "Saha Institute of Nuclear Physics", "Max-Planck-Institut fur extraterrestrische Physik", "Universidad Complutense", "Instituto de Astrof'isica de Canarias", "Universidad de la Laguna", "Dpto Astrof'isica", "University of L'od'z", "Deutsches Elektronen-Synchrotron", "Institut de F'isica d'Altes Energies", "The Barcelona Institute of Science", "Universitat Wurzburg", "Universita di Padova", "Institute for Space Sciences", "Technische Universitat Dortmund", "Finnish Magic Consortium", "Tuorla Astronomical Observatory", "University of Turku", "Astronomy Division", "University of Oulu", "Unitat de F'isica de les Radiacions", "Departament de F'isica", "Universitat Aut'onoma de Barcelona", "Japanese Magic Consortium", "The University of Tokyo", "Department of Engineering Physics", "Hakubi Center", "Kyoto University", "Tokai University", "The University of Tokushima", "Inst for Nucl Research", "Nucl Energy", "Universita' di Pisa", "Now at Centro Brasileiro de Pesquisas F'isicas", "Rio de Janeiro", "Nasa Goddard Space Flight Center", "Humboldt University of Berlin", "Institut fur theoretische Physik", "Berlin Germany", "also at University of Trieste", "now at Ecole polytechnique f'ed'erale de Lausanne", "now at Max-Planck-Institut fur Kernphysik", "also at Japanese Magic Consortium", "now at Finnish Centre for Astronomy with Eso", "also at INAF-Trieste", "Dept of Physics Astronomy", "University of Bologna", "also at Isdc - Science Data Center for Astrophysics", "A Misaki Department of Physics", "Department of Physics Astronomy", "University of Maryland", "College Park", "University of Utah", "Salt lake City", "Physics Department", "M L Sukhadia University", "Washington State University", "St Louis", "Fred Lawrence Whipple Observatory", "Harvard--Smithsonian Center for Astrophysics", "School of Cosmic Physics", "University College Dublin", "University of Southern California", "Los P Angeles", "National University of Ireland Galway", "Purdue University", "West Lafayette", "Center for Computational Astrophysics", "Tsinghua University", "Iowa State University", "525 Davey Lab", "Pennsylvania State University", "University Park", "University of Minnesota", "Astronomy Department", "Adler Planetarium", "Astronomy Museum", "the Bartol Research Institute", "University of Delaware", "Columbia University", "New York", "University of Iowa", "Van Allen Hall", "Iowa City", "DePauw University", "Barnard College", "Enrico Fermi Institute", "University of Chicago", "Instituto de Astronomia y Fisica del Espacio", "Ciudad de Buenos Aires", "Institute of Metal Physics", "University of Potsdam", "Department of Astrophysical Sciences", "Cork Institute of Technology", "Georgia Institute of Technology", "Santa Cruz Institute for Particle Physics", "Santa Cruz", "Argonne National Laboratory", "University of Johannesburg", "South Africa", "INAF-Osservatorio Astrofisico di Torino", "University of Michigan", "Ann Arbor", "Astronomical Institute", "St Petersburg State University", "St Petersburg", "Pulkovo Astronomical Observatory", "Institute for Particle Physics", "University of Crete", "Foundation for Research", "Circolo Astrofili Talmassons", "Osservatorio Astrofisico della Regione Autonoma Valle d'Aosta", "Abastumani Astrophysical Observatory", "Engelhardt Astronomical Observatory", "Kazan Federal University", "Guangzhou University", "Graduate Institute of Astronomy", "National Central University", "College of Materials Science", "952 Engineering", "Aoyama Gakuin University", "Sagamihara Kanagawa", "University of Colorado Denver", "Brigham Young University", "Tokyo Institute of Technology", "Meguro City", "Instituto Nacional de Astrof'isica", "'optica y Electr'onica", "Instututo de Astronomia y Meteorologia", "Dpto de Fisica", "Universidad de Guadalajara", "Steward Observatory", "University of Arizona", "Space Telescope Science Institute", "Pomona College", "University of Leicester", "Asi Science Data Center", "Via del Politecnico", "I-00133 Roma", "University of Trento", "Center for Space Research", "Exploration in Space Science", "Universities Space Research Association", "Astro Space Center of the Lebedev Physical Institute", "Max--Planck--Institut fur Radioastronomie", "Observatori Astronomic", "Universitat Politecnica de Valencia", "Departament d'Astronomia i Astrof'isica", "Crimean Astrophysical Observatory", "Sternberg Astronomical Institute", "Mcgill University", "Institute of Radio Astronomy", "Space Applications", "Remote Sensing", "National Observatory of Athens", "Whittier College", "Aalto University Metsahovi Radio Observatory", "Inaf Istituto di Radioastronomia", "Sezione di Noto", "Stazione Radioastronomica di Medicina", "M Guainazzi Iasfinaf Bologna", "Inaf - Osservatorio Astrofisico di Catania", "Cahill Center for Astronomy", "California Institute of Technology" ], "corpus_id": 11162445, "doc_id": "11162445", "n_citations": 35, "n_key_citations": 5, "score": 0, "title": "Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009", "venue": "", "year": 2016 }, { "abstract": "We present recent advances in understanding of the ground and excited states of the electron phonon coupled systems obtained by novel methods of Diagrammatic Monte Carlo and Stochastic Optimization, which enable the approximation free calculation of Matsubara Green function in imaginary times and perform unbiased analytic continuation to real frequencies. We present exact numeric results on the ground state properties, Lehmann spectral function and optical conductivity of different strongly correlated systems: Frohlich polaron, Rashba Pekar exciton polaron, pseudo Jahn Teller polaron, exciton, and interacting with phonons hole in the t J model.", "author_names": [ "Andrei S Mishchenko", "N Nagaosa Crest", "Japan Science", "Technology Agency", "Russian Research CenterKurchatov Institute", "The University of Tokyo" ], "corpus_id": 14234416, "doc_id": "14234416", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Spectroscopic Properties of Polarons in Strongly Correlated Systems by Exact Diagrammatic Monte Carlo Method", "venue": "", "year": 2007 }, { "abstract": "Systematic self monitoring of glycaemia represents acornerstone in intensified insulin therapy. In fact,self monitoring of blood glucose (SMBG) marksprobably the most important advance in diabetescare since the discovery of insulin. However, at leasttwo aspects make conventional SMBG difficult. Fin ger pricking to obtain the droplet of blood is regardedby many patients as even more daunting and painfulthan insulin injections [1] On the other hand, spotmeasurements of blood glucose, even if performedseveral times daily, only provide an incomplete pic ture of the blood glucose changes occurring over thewhole day. A continuous and reliable in vivo glucosemonitoring system would allow diabetic patients tocheck their metabolic control at their convenience.This would supply the diabetic patient with all infor mation required to optimise insulin therapy and,possibly, to improve metabolic control. Further more acute metabolic deteriorations, such as hypo glycaemic episodes, should easily become detectableby a continuously working glucose sensor.Several minimally invasive and non invasive ap proaches have been studied to monitor blood glucosemore or less continuously: 1) Implantable subcutane ous (s.c. glucose sensors, 2) S.c. interstitial fluidsampling by microdialysis or open tissue microperfu sion, 3) Transdermal glucose monitoring systems, 4)Optical glucose sensors. The minimally invasive ap proaches (1 and 2) are based on the analysis of inter stitial fluid. Insertion of electrodes into the s.c. tissuehas not yet resulted in a glucose sensor that could beused reliably for longer periods of time in humans[2 5] Lack of biocompatibility of the electrode sur face results in drifts of the electrode signal, associatedwith a loss of glucose sensitivity. The minimally inva sive microdialysis technique and related techniquesreduce such problems by pumping a perfusatethrough a dialysis fibre inserted in the subcutaneoustissue [6 10] Glucose diffuses from the interstitialfluid into the perfusate and is measured ex vivo. Inother approaches devices are attached to the skin tocollect glucose containing fluid transdermally [11].We will not review these minimally invasive ap proaches for glycaemic monitoring but will focus onnon invasive optical glucose sensors that avoid anumber of the problems of former approaches. Wewill discuss the problems of reliable glucose monitor ing using the spectrometric absorption technologyand present a novel approach making use of the factthat the variation of blood glucose levels changes thelight scattering properties of skin tissue.In vivo glucose monitoringby light absorption measurementSome research groups are trying to develop non inva sive glucose monitoring systems based on absorptionmeasurements [12 16] Up to now, however, nonehas been converted into a reliable glucose monitoringsystem, although a number of companies have pre sented or announced glucose monitoring devices us ing similar approaches.Spectrophotometry is an established method forthe quantification of solutes in liquids. It is based onsolute specific absorption bands in the visible (VIS),near infra red (NIR) or mid infra red (MIR) spectralrange. Quantification of the solutes is possible by de termination of light attenuation caused by absorptionat a single wavelength when taking the light pathlength (i.e. the cuvette thickness) into account. Thesolution has to be clear, as light scattering would re sult in an additional attenuation of light.", "author_names": [ "Lutz Heinemann", "Gunther Schmelzeisen-Redeker", "On behalf of the European Society of Paediatric Radio Force" ], "corpus_id": 6755621, "doc_id": "6755621", "n_citations": 98, "n_key_citations": 3, "score": 0, "title": "Non invasive continuous glucose monitoring in Type I diabetic patients with optical glucose sensors", "venue": "Diabetologia", "year": 1998 } ]

[ { "abstract": "Molecular recognition between complementary strands of DNA allows construction on a nanometre length scale. For example, DNA tags may be used to organize the assembly of colloidal particles, and DNA templates can direct the growth of semiconductor nanocrystals and metal wires. As a structural material in its own right, DNA can be used to make ordered static arrays of tiles, linked rings and polyhedra. The construction of active devices is also possible for example, a nanomechanical switch, whose conformation is changed by inducing a transition in the chirality of the DNA double helix. Melting of chemically modified DNA has been induced by optical absorption, and conformational changes caused by the binding of oligonucleotides or other small groups have been shown to change the enzymatic activity of ribozymes. Here we report the construction of a DNA machine in which the DNA is used not only as a structural material, but also as 'fuel' The machine, made from three strands of DNA, has the form of a pair of tweezers. It may be closed and opened by addition of auxiliary strands of 'fuel' DNA; each cycle produces a duplex DNA waste product.", "author_names": [ "Bernard Yurke", "Andrew J Turberfield", "Allen P Mills", "Friedrich C Simmel", "Jennifer Neumann" ], "corpus_id": 2064216, "doc_id": "2064216", "n_citations": 1741, "n_key_citations": 43, "score": 1, "title": "A DNA fuelled molecular machine made of DNA", "venue": "Nature", "year": 2000 }, { "abstract": "Molecular recognition between complementary strands of DNA allows construction on a nanometre length scale. For example, DNA tags may be used to organize the assembly of colloidal particles, and DNA templates can direct the growth of semiconductor nanocrystals and metal wires. As a structural material in its own right, DNA can be used to make ordered static arrays of tiles, linked rings and polyhedra. The construction of active devices is also possibleDfor example, a nanomechanical switch, whose conformation is changed by inducing a transition in the chirality of the DNA double helix. Melting of chemically modi(r)ed DNA has been induced by optical absorption, and conformational changes caused by the binding of oligonucleotides or other small groups have been shown to change the enzymatic activity of ribozymes. Here we report the construction of a DNA machine in which the DNA is used not only as a structural material, but also as `fuel' The machine, made from three strands of DNA, has the form of a pair of tweezers. It may be closed and opened by addition of auxiliary strands of `fuel' DNA; each cycle produces a duplex DNA waste product. Single strands of DNA composed of complementary sequences of the bases adenine, cytosine, guanine and thymine (A, C, G and T) hybridize to form a stable duplex (double helix) bound together by hydrogen bonds between complementary base pairs (A+ T and C+ G) Our machine is prepared by mixing stoichiometric quantities of three strands, A, B and C, in SPSC buffer (see Methods) at 20 8C to give a (r)nal concentration of 1 mM; the base sequences chosen for the three strands are given in Fig. 1. The structure and operation of the machine are shown in Fig. 2. Strand A consists of two 18 base sequences which hybridize with complementary sequences at the ends of strands B and C to form two stiff arms; the hinge is formed from a four base single stranded region of A between the regions hybridized to strands B and C. In the machine's rest state, the remaining unhybridized 24 base portions of the 42 base strands B and C dangle oppily from the ends of the tweezers: double stranded DNA has a persistence length of the order of 100 base pairs, whereas at 1 M salt concentration singlestranded DNA has a persistence length of about 1 nm (ref. 16) or approximately three bases. Strand A is labelled at the 59 and 39 ends with dyes TET (59 tetrachlorouorescein phosphoramidite) and TAMRA (carboxytetramethylrhodamine) respectively. When TET is excited by the 514.5 nm emission of an argon ion laser, it uoresces with a peak emission wavelength of 536 nm; this emission is quenched by resonant intramolecular energy transfer from TET to TAMRA (a longer wavelength dye whose absorption band overlaps the emission band of TET) with an ef(r)ciency that decreases rapidly as the distance between the dyes increases. Fluorescence quenching is used as an indicator to titrate strands B and C against A; as half of A is straightened from a random coil by hybridization with B (or C) the mean separation between the dye groups on A increases leading to a (r)vefold increase in the uorescence intensity. The cumulative effect of hybridization with both B and C is a sevenfold increase in uorescence intensity in the rest state. The assembled tweezers are opened and closed with fuel strands F and FA. The 56 base closing strand F consists of two consecutive 24base sections, which are complementary to the dangling ends of B and C, with an additional 8 base overhang section. Figure 2b shows how closing strand F hybridizes with the free ends of strands B and C, pulling the ends of the tweezers together. The average free energy change associated with the hybridization of a complementary base pair is 78 meV 1.8 kcal mol) at 20 8C (ref. 19) and the separation between base pairs in single stranded DNA is 0.43 nm (ref. 20) giving an average closing force of about 15 pN which is consistent with that required to pull apart double stranded DNA. This is at the upper end of the range of measured forces exerted by singlegroup kinesin and myosin motors. The second component of the fuel is removal strand FA, the complement of F: the additional free energy gained when the overhang (single stranded in the initial state) hybridizes with FA ensures that when a stoichiometric quantity of FA is added it removes F from the machine to form a doublestranded waste product FFA and returns the tweezers to the open state. Hybridization between the closing and removal fuel strands is expected to occur (r)rst at the exposed overhang and to proceed by branch migration, a random walk of the junction between the region of F newly hybridized to the removal strand FA and the region still hybridized to the tweezer components B and C; this branch migration continues until both B and C have been completely displaced and the FFA duplex diffuses away. The random walk occurs suf(r)ciently quickly that the rate limiting step in such strand displacement reactions is the endothermic nucleation of a region in which complementary bases are joined (in this case, the nucleation of hybridization between the F and FA strands) this", "author_names": [ "Nathalie Capron", "Francesco G Gatti", "FrancEois Kajzar", "David A Leigh", "Francesco Zerbetto", "Songwei Zhang" ], "corpus_id": 9884081, "doc_id": "9884081", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A DNA fuelled molecular machine made of DNA", "venue": "", "year": null }, { "abstract": "The predictable and specific hybridization of complementary strands of DNA allows construction on a nanometre length scale: (i) DNA tags may be used to organize the assembly of colloidal particles; (ii) DNA may be used as a structural material in its own right to make complicated objects, e.g. ordered arrays of tiles, linked rings and polyhedra; (iii) DNA may act as a template to direct the growth of semiconductor nanocrystals and metal wires. These are static structures: Seeman and co workers have produced an active device, a nanomechanical switch whose conformation is changed by inducing a B Z transition (from a rightto a left handed double helix) by changing the composition of the buffer solution. Conformational changes caused by the binding of oligonucleotides or other small molecules have been shown to change the enzymatic activity of ribozymes We report the construction of a new class of active nanostructure: a machine in which DNA is used not only as a structural material but also as a fuel.", "author_names": [ "Bernard Yurke", "Andrew J Turberfield Mills" ], "corpus_id": 81738347, "doc_id": "81738347", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A molecular machine made and powered by DNA", "venue": "", "year": 2000 }, { "abstract": "Significance The circadian clock is an internal molecular 24 h timer that is critical to life on Earth. We describe a series of artificial intelligence (AI) and machine learning (ML) based approaches that enable more cost effective analysis and insight into circadian regulation and function. Throughout the manuscript, we illuminate what is inside the ML \"black box\" via explanation or interpretation of predictive ML models. Using this interpretation of our models, we derive biological insights into why a prediction was made, alongside accurate predictions. Most innovatively, we use only DNA sequence features for accurate circadian gene expression prediction. Using explainable AI, we define possible, responsible regulatory elements as we make these predictions; this critically requires no prior knowledge of regulatory elements. The circadian clock is an important adaptation to life on Earth. Here, we use machine learning to predict complex, temporal, and circadian gene expression patterns in Arabidopsis. Most significantly, we classify circadian genes using DNA sequence features generated de novo from public, genomic resources, facilitating downstream application of our methods with no experimental work or prior knowledge needed. We use local model explanation that is transcript specific to rank DNA sequence features, providing a detailed profile of the potential circadian regulatory mechanisms for each transcript. Furthermore, we can discriminate the temporal phase of transcript expression using the local, explanation derived, and ranked DNA sequence features, revealing hidden subclasses within the circadian class. Model interpretation/explanation provides the backbone of our methodological advances, giving insight into biological processes and experimental design. Next, we use model interpretation to optimize sampling strategies when we predict circadian transcripts using reduced numbers of transcriptomic timepoints. Finally, we predict the circadian time from a single, transcriptomic timepoint, deriving marker transcripts that are most impactful for accurate prediction; this could facilitate the identification of altered clock function from existing datasets.", "author_names": [ "Laura-Jayne Gardiner", "Rachel Rusholme-Pilcher", "Joshua Colmer", "Hannah Rees", "Juan Manuel Crescente", "Anna Paola Carrieri", "Susan Duncan", "Edward O Pyzer-Knapp", "Ritesh Krishna" ], "corpus_id": 236935240, "doc_id": "236935240", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Interpreting machine learning models to investigate circadian regulation and facilitate exploration of clock function", "venue": "Proceedings of the National Academy of Sciences", "year": 2021 }, { "abstract": "Significance DNA mismatch repair (MMR) is critical to avoid mutations that can lead to genetic disease, cancer, and death. The MMR system is evolutionarily conserved from bacteria to humans and is an example of a remarkable molecular machine. Here we show that this machine operates unidirectionally with respect to the chromosome of Escherichia coli. The most likely explanation for this directionality is that the MMR machinery is associated with the complex responsible for DNA replication. We suggest that this association facilitates the mechanism of strand discrimination in MMR. Defects in DNA mismatch repair (MMR) result in elevated mutagenesis and in cancer predisposition. This disease burden arises because MMR is required to correct errors made in the copying of DNA. MMR is bidirectional at the level of DNA strand polarity as it operates equally well in the 5' to 3' and the 3' to 5' directions. However, the directionality of MMR with respect to the chromosome, which comprises parental DNA strands of opposite polarity, has been unknown. Here, we show that MMR in Escherichia coli is unidirectional with respect to the chromosome. Our data demonstrate that, following the recognition of a 3 bp insertion deletion loop mismatch, the MMR machinery searches for the first hemimethylated GATC site located on its origin distal side, toward the replication fork, and that resection then proceeds back toward the mismatch and away from the replication fork. This study provides support for a tight coupling between MMR and DNA replication.", "author_names": [ "A M Mahedi Hasan", "David R F Leach" ], "corpus_id": 2497139, "doc_id": "2497139", "n_citations": 10, "n_key_citations": 2, "score": 0, "title": "Chromosomal directionality of DNA mismatch repair in Escherichia coli", "venue": "Proceedings of the National Academy of Sciences", "year": 2015 }, { "abstract": "Significance Tailed bacteriophages and herpes viruses use powerful molecular machines to package their genomes into a viral capsid using ATP as fuel. Recent biophysical and structural studies have provided a detailed picture of mechanochemistry of DNA packaging. However, little is known about the packaging initiation step owing to its transient nature. Here, we reconstituted the bacteriophage T4 DNA packaging machine and imaged individual packaging events in real time. We discovered that initiations occur in bursts and through multiple pathways, including direct capture of DNA by the capsid portal, and they require rapid input of energy, analogous to the cranking of an engine. This system opens a new window into the mechanism of viral genome packaging initiation and the evolution of icosahedral viruses. Viral DNA packaging motors are among the most powerful molecular motors known. A variety of structural, biochemical, and single molecule biophysical approaches have been used to understand their mechanochemistry. However, packaging initiation has been difficult to analyze because of its transient and highly dynamic nature. Here, we developed a single molecule fluorescence assay that allowed visualization of packaging initiation and reinitiation in real time and quantification of motor assembly and initiation kinetics. We observed that a single bacteriophage T4 packaging machine can package multiple DNA molecules in bursts of activity separated by long pauses, suggesting that it switches between active and quiescent states. Multiple initiation pathways were discovered including, unexpectedly, direct DNA binding to the capsid portal followed by recruitment of motor subunits. Rapid succession of ATP hydrolysis was essential for efficient initiation. These observations have implications for the evolution of icosahedral viruses and regulation of virus assembly.", "author_names": [ "Reza Vafabakhsh", "Kiran Kondabagil", "Tyler M Earnest", "Kyung Suk Lee", "Zhihong Zhang", "Li Dai", "Karin A Dahmen", "Venigalla B Rao", "Taekjip Ha" ], "corpus_id": 39911040, "doc_id": "39911040", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "Single molecule packaging initiation in real time by a viral DNA packaging machine from bacteriophage T4", "venue": "Proceedings of the National Academy of Sciences", "year": 2014 }, { "abstract": "In this work, biomolecules, such as membrane proteins, lipids, and DNA, were identified and their spatial distribution was mapped within a single Escherichia coli cell by Raman hyperspectral imaging. Raman spectroscopy allows direct, nondestructive, rapid, and cost effective analysis of biological samples, minimizing the sample preparation and without the need of chemical label or immunological staining. Firstly, a comparison between an air dried and a freeze dried cell was made, and the principal vibrational modes associated to the membrane and nucleic acids were identified by the bacterium's Raman chemical fingerprint. Then, analyzing the Raman hyperspectral images by multivariate statistical analysis, the bacterium biological status was investigated at a subcellular level. Principal components analysis (PCA) was applied for dimensionality reduction of the spectral data, then spectral unmixing was performed by multivariate curve resolution alternating least squares (MCR ALS) Thanks to multivariate data analysis, the DNA segregation and the Z ring formation of a replicating bacterial cell were detected at a sub micrometer level, opening the way to real time molecular analysis that could be easily applied on in vivo or ex vivo biological samples, avoiding long preparation and analysis process.", "author_names": [ "Giulia Barzan", "Alessio Sacco", "Luisa Mandrile", "Andrea Mario Giovannozzi", "Chiara Portesi", "Andrea Mario Rossi" ], "corpus_id": 234832163, "doc_id": "234832163", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hyperspectral Chemical Imaging of Single Bacterial Cell Structure by Raman Spectroscopy and Machine Learning", "venue": "", "year": 2021 }, { "abstract": "The anti tumor potency of poly(ADP ribose) polymerase (PARP) inhibitors (PARPis) has been linked to trapping of PARP1 on damaged chromatin. However, little is known about their impact on PARP2, an isoform with overlapping functions at DNA lesions. Whether the release of PARP1/2 from DNA lesions is actively catalyzed by molecular machines is also not known. We found that PARPis robustly trap PARP2 and that the helicase ALC1 (CHD1L) is strictly required for PARP2 release. Catalytic inactivation of ALC1 quantitatively traps PARP2 but not PARP1. ALC1 manipulation impacts the response to single strand DNA breaks through PARP2 trapping, potentiates PARPi induced cancer cell killing, and mediates synthetic lethality upon BRCA deficiency. The chromatin remodeler ALC1 actively drives PARP2 turnover from DNA lesions, and PARP2 contributes to the cellular responses of PARPi. This suggests that disrupting the ATP fueled remodeling forces of ALC1 might enable therapies that selectively target the DNA repair functions of PARPs in cancer.", "author_names": [ "Charlotte Blessing", "Imke K Mandemaker", "Claudia Gonzalez-Leal", "Julia Preisser", "Adrian Schomburg", "Andreas G Ladurner" ], "corpus_id": 227297734, "doc_id": "227297734", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "The Oncogenic Helicase ALC1 Regulates PARP Inhibitor Potency by Trapping PARP2 at DNA Breaks.", "venue": "Molecular cell", "year": 2020 }, { "abstract": "Machines undergo repeated energy (fuel) driven cycling between various functional and structural states. Such cycling involves motions of the machine parts, which take place in a highly coordinated manner in time and space. This description applies not only to man made machines but also to the molecular machines that mediate many of the key processes in all forms of life [1] Examples include protein synthesis by the ribosome, DNA unwinding by helicases during replication, protein degradation by the proteasome and protein folding by chaperones. The coordinated movements of most biomolecular machines are achieved by allosteric regulation of ATP binding and hydrolysis. Consequently, a molecular level understanding of how the essential machines of life work requires invoking and further developing allosteric theory. Hence, the motivation for the Royal Society Discussion Meeting entitled 'Allostery and molecular machines' that took place in June 2017. The meeting brought together scientists interested in allostery, in general, with others who are studying specific biomolecular machines of interest. The meeting led to many interesting discussions and resulted in this special issue of the Philosophical Transactions B In 1965, Monod, Wyman Changeux published a seminal paper [2] that described a so called 'concerted model' (referred to here and generally as the MWC model) for cooperative ligand binding by oligomeric proteins. This issue contains a paper by one of the co authors of this landmark paper in which the MWC model is explained in brief and its application to the nicotinic acetylcholine receptor is then described [3] The MWC model remains important but its elegance has come at the price of several restrictive assumptions. One key assumption is that cooperativity is due to a shift in equilibrium between different quaternary", "author_names": [ "George H Lorimer", "Amnon Horovitz", "Tom C B McLeish" ], "corpus_id": 25758923, "doc_id": "25758923", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Allostery and molecular machines", "venue": "Philosophical Transactions of the Royal Society B: Biological Sciences", "year": 2018 }, { "abstract": "Molecular machines have previously been designed that are propelled by DNAzymes1 3, protein enzymes4 6 and strand displacement7 9. These engineered machines typically move along precisely defined one and two dimensional tracks. Here, we report a DNA walker that uses hybridisation to drive walking on DNA coated microparticle surfaces. Through purely DNA:DNA hybridisation reactions, the nanoscale movements of the walker can lead to the generation of a single stranded product and the subsequent immobilisation of fluorescent labels on the microparticle surface. This suggests that the system could be of use in analytical and diagnostic applications, similar to how strand exchange reactions in solution have been used for transducing and quantifying signals from isothermal molecular amplification assays10,11. The walking behaviour is robust and the walker can take more than 30 continuous steps. The traversal of an unprogrammed, inhomogeneous surface is also due entirely to autonomous decisions made by the walker, behaviour analogous to amorphous chemical reaction network computations12,13 that have been shown to lead to pattern formation14 17.", "author_names": [ "Cheulhee Jung", "Peter B Allen", "Andrew D Ellington" ], "corpus_id": 6944369, "doc_id": "6944369", "n_citations": 189, "n_key_citations": 0, "score": 0, "title": "A stochastic DNA walker that traverses a microparticle surface", "venue": "Nature nanotechnology", "year": 2016 } ]

[ { "abstract": "Single photon sources are basic building blocks for quantum communications, processing, and metrology. Solid state quantum emitters in semiconductors have the potential for robust and reliable generation of photons, and atomically thin transition metal dichalcogenides, such as MoS2, MoSe2, WS2, and WSe2, are a promising new class of two dimensional semiconductors with a direct optical bandgap in the visible or near IR. Here, we observe bright and stable single photon emission from localized excitons in a monolayer of tungsten diselenide (WSe2) The emitters appear at the edges of the flakes and are linearly polarized. The spectral width of their emission is below 120 meV in a freestanding WSe2 monolayer. Photoluminescence excitation spectroscopy reveals the excitonic nature of the emitters and provides evidence that these single excitons originate from free excitons trapped in local potential wells at the edges of the atomically thin flakes. We find that the emitters can also be deterministically created by scratching the WSe2 monolayer. Their excellent spectral stability implies that these localized single photon emitters could find application in optoelectronics. Our results light the way to single exciton physics and quantum optics with atomically thin semiconductors.", "author_names": [ "Philipp Tonndorf", "Robert Schmidt", "Robert J Schneider", "Johannes Kern", "Michele Buscema", "Gary A Steele", "Andres Castellanos-Gomez", "Herre S J van der Zant", "S Michaelis de Vasconcellos", "Rudolf Bratschitsch" ], "corpus_id": 137394181, "doc_id": "137394181", "n_citations": 275, "n_key_citations": 9, "score": 2, "title": "Single photon emission from localized excitons in an atomically thin semiconductor", "venue": "", "year": 2015 }, { "abstract": "The demonstration of stable quantum emitters in semiconductor transition metal dichalcogenides (TMDs) [1] and insulating hexagonal boron nitride (hBN) [2] has begun to impact the field of integrated quantum optics due to the promising properties of two dimensional materials, such room temperature operation, stretchability, heterogeneous device assembly and straightforward integration with photonic circuits. Nevertheless, major questions remain. Single photon emitters (SPEs) in hBN are associated with atom like defects that confine electronic levels deep within the wide band gap. As recently reported, hBN can host several different families of emitters with emission energy that spans over a large spectral band [3] On the other hand, quantum emission in TMDs is attributed to individual excitons bound to defects or impurities of the crystal structure. Recently, it has been shown that strain pockets can create potential traps able to confine single excitons producing SPEs with high spatial control [4,5] Nevertheless, the relation between strain and emission energy is still not fully clear. The lack of a clear understanding of the nature of these defects [6] brings along the challenge of controlling the emission energy and of the deterministic creation of such emitters. These crucial aspects present central problems for developing identical single photon sources and for integration with photonic platforms. We developed a material processing based on ion irradiation and high temperature annealing of exfoliated hBN that sharply improves the single photon purity with g(2)(0) 0.08, and brightness with emission rate exceeding 10^7 counts/sec at room temperature. We also showed that the emitters persist material transfer process allowing to integrate them onto different platforms. To investigate the wide span of the emission energy we applied external compressive and tensile strain. Emitters in hBN show different tuning coefficients up to 6 meV per strain unit [7] Furthermore, we performed photoluminescence excitation experiments at cryogenic temperature on different families of emitters. Our experimental results allow to identify the excited states of these atom like systems and shine light on the characteristic level structures of the different families of emitters in hBN and can potentially help to reduce the spectral wandering with more efficient resonant excitation. Recently, new methods to develop quantum emitters in monolayer TMDs have been reported [4,5] They rely on the strain induced by nanostructures in the substrate. This technique allows to create emitters with high spatial resolution. Unfortunately, it is still not possible to engineer the single photon energy with strain since the relation between strain and the emission energy of the localized excitons in TMDs is still not fully understood. To answer this question, we transferred CVD grown WSe2 on a pre patterned Si3N4 substrate with pillars of 200 nm in diameter. We combined hyperspectral measurements, which allow to locate a single energy emission peak with a spatial resolution of around 10 nm, with strain measurements. Strain is measured optically by resolving in polarization the intensity of the second harmonic signal. This method allows to measure the photoelastic tensor of TMD monolayers and to retrieve the magnitude of biaxial strain with a spatial resolution of 200 nm [8] The combination of these techniques opens a new way to investigate the correspondence between the strain magnitude created by a nanopatterned substrate and the emission energy of the single photon emitted due to exciton localization in the nanostructures. [1] Perebeinos, V. Nat. Nano. 10, 485 (2015) [2] Tran, T. T. et al. Nat. Nano. 11, 37 (2016) [3] Tran, T. T. et al. ACS Nano 10, 7331 (2016) [4] Branny, A. et al. Nature Comm. 8, 15053 (2017) [5] Palacios Berraquero, C. et al. Nature Comm. 8, 15093 (2017) [6] Tawfik, S.A. et al. Nanoscale 9, 13575 (2017) [7] Grosso, G. Moon, H, et al. Nature Comm. 8, 705 (2017) [8] L. Mennel, et al. Nature Comm. 9, 516 (2018)", "author_names": [ "Gabriele Grosso", "Hyowon Moon", "D Englund" ], "corpus_id": 139688788, "doc_id": "139688788", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Spectroscopy of single photon emitters based on 2D materials (Conference Presentation)", "venue": "2D Photonic Materials and Devices II", "year": 2019 }, { "abstract": "Deterministic Single Photon Sources in 2 D Semiconductors Two dimensional semiconductors present a new potential solid state host for single photon sources. A notable characteristic of these systems compared with traditional single photon sources, such as InGaAs quantum dots or color centers in diamond, is the ability to trap single excitons at a surface. This asset could unlock the potential for developing highly effi cient photon extraction mechanisms and for coupling confi ned excitons to photonic structures and other quantum systems. Since 2015, single photon emitt ing sites of unknow n origin have been reported to appear at random locations in monolayer fl akes of WSe2, WS2 and MoSe2. This year, we were able to deterministically engineer such sources at precise locations with a 96 percent yield, in unlimited numbers, in a scalable manner and with bett er optical properties than their randomly occurring counterparts.3 We accomplished this deterministic source by deforming the material locally at the nanoscale, using patt erned substrates. We fi rst exfoliated monolayer fl akes of WSe2 and WS2 from bulk crystals. Then, we transferred the fl akes onto silica substrates patt erned with square arrays of nanopillars, spaced 4 mm apart and ranging from 100 to 200 nm in height and with a 90 nm apex diameter. Atomicforce microscopy scans show that the fl akes tent over each nanopillar and att ach by Van der Waals forces to the fl at areas of the substrate in between. Low temperature photoluminescence (PL) measurements showed a brightening of PL and narrow spectral lines from the pillar locations. Photon correlation measurements on these narrow lines confi rmed the single photon nature of the emission, and high resolution spectral measurements revealed a fi ne structure in the majority of dots. The parameters measured are very similar to those measured for the randomly appearing single photon emitt ing sites in the same materials, which suggests a common origin. Characterization of the quantum emission with increasing pillar height also yielded interesting results: the number of narrow lines per site decreases and the spectral wandering improves by an order of magnitude compared with the random emission sites. We believe that this work paves the way for a true singlephoton emitt er that can be easily scaled up and integrated with other photonic components. In addition, as a new platform for deterministic quantum light matt er interaction between single excitons and photons, it allows researchers to explore the potential for optical single spin control toward quantum information applications. OPN", "author_names": [ "Duhee Yoon", "Anna K Ott", "Andrea C Ferrari" ], "corpus_id": 221693963, "doc_id": "221693963", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Deterministic Single Photon Sources in 2 D Semiconductors", "venue": "", "year": 2017 }, { "abstract": "We observe stable and narrowband single photon emission from localized quantum emitters in a WSe 2 monolayer. Photoluminescence excitation spectroscopy reveals that the emission originates from single excitons trapped in a local potential well.", "author_names": [ "Philipp Tonndorf", "Robert Schmidt", "Johannes Kern", "Michele Buscema", "Gary A Steele", "Andres Castellanos-Gomez", "Herre S J van der Zant", "S Michaelis de Vasconcellos", "Rudolf Bratschitsch" ], "corpus_id": 117098728, "doc_id": "117098728", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Single photon emission from localized excitons in monolayer WSe 2", "venue": "CLEO 2015", "year": 2015 }, { "abstract": "We observe stable and narrowband single photon emission from localized quantum emitters in a WSe2 monolayer. Photoluminescence excitation spectroscopy reveals that the emission originates from single excitons trapped in a local potential well.", "author_names": [ "Philipp Tonndorf", "Robert Schmidt", "Johannes Kern", "Michele Buscema", "Gary A Steele", "Andres Castellanos-Gomez", "Herre S J van der Zant", "Steffen Michaelis de Vasconcellos", "Rudolf Bratschitsch" ], "corpus_id": 24604617, "doc_id": "24604617", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Single photon emission from localized excitons in monolayer WSe2", "venue": "2015 Conference on Lasers and Electro Optics (CLEO)", "year": 2015 }, { "abstract": "We report on the principle and realization of a new trap for excitons the diamond electrostatic trap which uses a single electrode to create a confining potential for excitons. We also create elevated diamond traps which permit evaporative cooling of the exciton gas. We observe the collection of excitons towards the trap center with increasing exciton density. This effect is due to screening of disorder in the trap by the excitons. As a result, the diamond trap behaves as a smooth parabolic potential which realizes a cold and dense exciton gas at the trap center.", "author_names": [ "Alexander A High", "A K Thomas", "Gabriele Grosso", "Mikas Remeika", "Aaron Tynes Hammack", "Andrew Meyertholen", "Michael M Fogler", "L V Butov", "Micah P Hanson", "Arthur C Gossard" ], "corpus_id": 33526567, "doc_id": "33526567", "n_citations": 42, "n_key_citations": 0, "score": 0, "title": "Trapping indirect excitons in a GaAs quantum well structure with a diamond shaped electrostatic trap.", "venue": "Physical review letters", "year": 2009 }, { "abstract": "Voltage tunable quantum traps confining individual spatially indirect and long living excitons are realized by providing a coupled double quantum well with nanoscale gates. This enables us to study the transition from confined multiexcitons down to a single, electrostatically trapped indirect exciton. In the few exciton regime, we observe discrete emission lines identified as resulting from a single dipolar exciton, a biexciton, and a triexciton, respectively. Their energetic splitting is well described by Wigner like molecular structures reflecting the interplay of dipolar interexcitonic repulsion and spatial quantization.", "author_names": [ "G J Schinner", "Jens Repp", "Enrico Schubert", "Ashish K Rai", "Dirk Reuter", "Andreas Dirk Wieck", "Alexander O Govorov", "Alexander W Holleitner", "Jorg P Kotthaus" ], "corpus_id": 34251926, "doc_id": "34251926", "n_citations": 48, "n_key_citations": 0, "score": 0, "title": "Confinement and interaction of single indirect excitons in a voltage controlled trap formed inside double InGaAs quantum Wells.", "venue": "Physical review letters", "year": 2013 }, { "abstract": "Measuring fluorescence photon statistics of single chains of a conjugated polymer we determine the lifetime of the metastable dark state, the triplet exciton. The single molecule emits single photons one at a time, giving rise to photon antibunching. These photons appear bunched in time over longer timescales because of excursions to the triplet dark state. Remarkably, this triplet intermittency in the fluorescence is spontaneously suppressed over timescales of seconds, implying that either triplet formation is inhibited; or that triplets are selectively quenched without the singlet fluorescence being affected. Such discrete switching in the strength of photon bunching is only seen in highly ordered and rigid chains of a ladder type conjugated polymer. It does not occur in single dye molecules. We propose that trapped photogenerated charges on the chain selectively quench triplets but not singlets, presumably because the effective diffusion length of triplets is longer along the highly rigid ladder type backbone.", "author_names": [ "Jakob Schedlbauer", "Ullrich Scherf", "Jan Vogelsang", "John M Lupton" ], "corpus_id": 219537195, "doc_id": "219537195", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Dynamic Quenching of Triplet Excitons in Single Conjugated Polymer Chains.", "venue": "The journal of physical chemistry letters", "year": 2020 }, { "abstract": "The temperature of Bose Einstein condensation and the fraction of particles in a condensate for a system of spatially indirect dipole excitons in an electrostatic ring trap have been found. If only levels of the radial motion close to the bottom of the potential well of the trap are populated considerably, the oscillatory model of the single particle spectrum is applicable. In this case, even the strong exciton exciton interaction can be taken into account.", "author_names": [ "Alexander V Chaplik" ], "corpus_id": 125561163, "doc_id": "125561163", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Bose Einstei condensation of dipolar excitons in a ring trap", "venue": "", "year": 2016 }, { "abstract": "We report on the principle and realization of a new trap for excitons the diamond electrostatic trap which uses a single electrode to create a confining potential for excitons. We also create elevated diamond traps which permit evaporative cooling of the exciton gas. We observe collection of excitons towards the trap center with increasing exciton density. This effect is due to screening of disorder in the trap by the excitons. As a result, the diamond trap behaves as a smooth parabolic potential which realizes a cold and dense exciton gas at the trap center.", "author_names": [ "Alexander A High", "A K Thomas", "Gabriele Grosso", "Mikas Remeika", "Aaron Tynes Hammack", "Andrew Meyertholen", "Michael M Fogler", "L V Butov", "Micah P Hanson", "Arthur C Gossard" ], "corpus_id": 119235745, "doc_id": "119235745", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Collection of indirect excitons in a diamond shaped electrostatic trap", "venue": "", "year": 2009 } ]

[ { "abstract": "Abstract The accomplishment of 1D semiconductor nanowires (SN) in the field of energy has attracted intense interest in recent years due to their advantageous properties (e.g. large surface area, unique surface chemistry, and tunable transport properties) Considerable efforts were devoted to explore 1D SN building blocks as the harvesting channel/unit (e.g. in thermal, chemical, mechanical, and solar energy applications) and as the storage media (for electrochemical energy) A wide bandgap tuning of SN in the range of 0.39 eV (in case of InAs nanowires) to 4.66 eV (in case of b Ga2O3 nanowires) due to quantum size effect makes them a suitable candidate for optoelectronic applications. This review focuses on 1D SN wherein the travel of electron and photon is confined in two directions but in one dimension. The SN emerged as promising nanostructures for developing electronic devices of high carrier mobilities (e.g. >12000 cm2V 1s 1 for holes and 3000 cm2V 1s 1 for electrons in case of Ge nanowires) A list of efficient fabrication strategies (e.g. vapor liquid solid [VLS] hard template approaches, and solution phase) are discussed along with ultrafast electron transport dynamics of SN and piezoelectric nanowires. The control on electrons, photons, and phonons transport makes 1D SN ideal for solid state energy conversion, harvesting, and storage applications. State of the art 1D SN energy nano systems have been demonstrated to yield diverse outcomes of high significance including single nanowire and array based photovoltaic cells (InP nanowires with a maximum power conversion efficiency up to 17.8% nanogenerators (SiGe nanowires with a maximum power output of 7.1 mW/cm2) supercapacitors (core shell hierarchical CoS@MoS2 nanowire array with an energy density of 95.7 Wh kg 1 at power density of 711.2 W kg 1) and lithium air batteries (3D freestanding hierarchical CuCo2O4 nanowires@Ni foam with an excellent specific capacity of 13654 mAh g 1 at 0.1 mA cm 2) This review will serve as a key platform to understand 1D SN to fabricate the next generation novel nano systems for developing efficient energy devices of high performance.", "author_names": [ "Monika Nehra", "Neeraj Dilbaghi", "Giovanna Marrazza", "Ajeet Kumar Kaushik", "Reza Abolhassani", "Yogendra Kumar Mishra", "Sandeep Kumar" ], "corpus_id": 224995283, "doc_id": "224995283", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "1D semiconductor nanowires for energy conversion, harvesting and storage applications", "venue": "", "year": 2020 }, { "abstract": "Semiconductor nanowires represent an important class of nanostructure building block for photovoltaics as well as direct solar to fuel application because of their high surface area, tunable bandgap and efficient charge transport and collection. In this talk, I will highlight several recent examples in this lab using semiconductor nanowires and their heterostructures for the purpose of solar energy harvesting. In addition, we have also discovered that the thermoconductivity of the silicon nanowires can be significantly reduced due to phonon scattering, pointing to a very promising approach to design better thermoelectrical materials. It is important to note that the engines that generate most of the world's power typically operate at only 30 40 per cent efficiency, releasing roughly 15 terawatts of heat to the environment. If this \"wasted heat\" could be recycled, the impact globally would be enormous. Our silicon nanowire thermoelectric technology could have a significant impact in alternative energy generation.", "author_names": [ "Peidong Yang" ], "corpus_id": 1841634, "doc_id": "1841634", "n_citations": 1071, "n_key_citations": 0, "score": 1, "title": "Semiconductor nanowires for energy conversion", "venue": "2010 3rd International Nanoelectronics Conference (INEC)", "year": 2010 }, { "abstract": "Semiconductor nanowires represent an important class of nanostructure building block for photovoltaics as well as direct solar to fuel application because of their high surface area, tunable bandgap and efficient charge transport and collection. In this talk, I will highlight several recent examples in this lab using semiconductor nanowires and their heterostructures for the purpose of solar energy harvesting. In addition, we have also discovered that the thermoconductivity of the silicon nanowires can be significantly reduced due to phonon scattering, pointing to a very promising approach to design better thermoelectrical materials. It is important to note that the engines that generate most of the world's power typically operate at only 30 40 per cent efficiency, releasing roughly 15 terawatts of heat to the environment. If this \"wasted heat\" could be recycled, the impact globally would be enormous. Our silicon nanowire thermoelectric technology could have a significant impact in alternative energy generation.", "author_names": [ "Peidong Yang" ], "corpus_id": 137444356, "doc_id": "137444356", "n_citations": 152, "n_key_citations": 3, "score": 0, "title": "Semiconductor nanowires for energy conversion", "venue": "", "year": 2010 }, { "abstract": "In this paper, a thermodynamic analysis on current photovoltaics is given within the Shockley Queisser model. Then the latest progresses of designing semiconductor nanowire arrays are introduced to achieve effective light trapping and reduce emission angle. Among them, non uniform nanowire arrays with gradient shapes hold both advantages of ultralow emission angle and light trapping, therefore which have attracted much research interest toward ultrahigh efficiency of solar energy conversion from visible to near infrared wavelength.", "author_names": [ "Tong Zhongying", "Xie Tian", "Ye Xin-Hui", "Xia Hui", "Li Ju-Zhu", "Zhang Shuai-Jun", "Jiang Xin-Yang", "Chen Ze-zhong", "Liang Tianxin" ], "corpus_id": 213727909, "doc_id": "213727909", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research progress on semiconductor nanowires for high efficiency solar energy conversion", "venue": "", "year": 2019 }, { "abstract": "Cubic semiconductor nanowires grown along <100> directions have been reported to be promising for optoelectronics and energy conversion applications, owing to their pure zinc blende structure without any stacking fault. But, till date, only limited success has been achieved in growing <100> oriented nanowires. Here we report the selective growth of stacking fault free <100> nanowires on a commercial transparent conductive polycrystalline fluorine doped SnO2 (FTO) glass substrate via a simple and cost effective chemical vapor deposition (CVD) method. By means of crystallographic analysis and density functional theory calculation, we prove that the orientation relationship between the Au catalyst and the FTO substrate play a vital role in inducing the selective growth of <100> nanowires, which opens a new pathway for controlling the growth directions of nanowires via the elaborate selection of the catalyst and substrate couples during the vapor solid liquid (VLS) growth process. The ZnSe nanowires grown on the FTO substrate are further applied as a photoanode in photoelectrochemical (PEC) water splitting. It exhibits a higher photocurrent than the ZnSe nanowires without preferential orientations on a Sn doped In2O3 (ITO) glass substrate, which we believe to be correlated with the smooth transport of charge carriers in ZnSe <100> nanowires with pure zinc blende structures, in distinct contrast with the severe electron scattering happened at the stacking faults in ZnSe nanowires on the ITO substrate, as well as the efficient charge transfer across the intensively interacting nanowire substrate interfaces.", "author_names": [ "Kai Zhang", "Yasir Abbas", "Saad Ullah Jan", "Lei Gao", "Yuan Ma", "Zhishan Mi", "Xianglei Liu", "Yimin Xuan", "Jian Ru Gong" ], "corpus_id": 214679750, "doc_id": "214679750", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Selective growth of stacking fault free <100> nanowires on a polycrystalline substrate for energy conversion application.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "Controlling the growth and composition of nanowires is key to building photovoltaics, thermoelectrics and betavoltaics with optimal performance.Controlling the growth and composition of nanowires is key to building photovoltaics, thermoelectrics and betavoltaics with optimal performance.", "author_names": [ "Melissae Stuart Fellet" ], "corpus_id": 139576489, "doc_id": "139576489", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Semiconductor nanowires improve the performance of energy conversion devices", "venue": "", "year": 2018 }, { "abstract": "Semiconductor nanowires are promising building blocks for next generation solar energy conversion at low cost, due to their large absorption cross sections. Here, the understanding of their absorption power is explored via computational and experimental methods as well as its use in other fields, such as bio physics.", "author_names": [ "Eleonora Frau", "Gozde Tutuncuoglu", "Federico Matteini", "H Potts", "Rune Federiksen", "Karen L Martinez", "Anna Fontcuberta i Morral", "Esther Alarcon-Llado" ], "corpus_id": 24297201, "doc_id": "24297201", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Understanding and exploiting optical properties in semiconductor nanowires for solar energy conversion", "venue": "2016 IEEE Photonics Society Summer Topical Meeting Series (SUM)", "year": 2016 }, { "abstract": "Semiconductor nanowires (NW) possess several beneficial properties for efficient conversion of solar energy into electricity and chemical energy. Due to their efficient absorption of light, short distances for minority carriers to travel, high surface to volume ratios, and the availability of scalable synthesis methods, they provide a pathway to address the low cost to power requirements for wide scale adaptation of solar energy conversion technologies. Here we highlight recent progress in our group towards implementation of NW components as photovoltaic and photoelectrochemical energy conversion devices. An emphasis is placed on the unique properties of these one dimensional (1D) structures, which enable the use of abundant, low cost materials and improved energy conversion efficiency compared to bulk devices.", "author_names": [ "Neil P Dasgupta", "Peidong Yang" ], "corpus_id": 14992692, "doc_id": "14992692", "n_citations": 54, "n_key_citations": 0, "score": 0, "title": "Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion", "venue": "", "year": 2014 }, { "abstract": "Pb doping of SnO2 nanowires grown by the vapor liquid solid mechanism on 1 nm Au/Si has been investigated between 500 and 1000 degC via the reaction of Sn containing Pb with O2 at 10 1 mbar. The SnO2 nanowires have diameters of 50 nm, lengths up to 100 mm, and a tetragonal rutile crystal structure, but they do not contain Pb because of its significant depletion during the temperature ramp and re evaporation from the surface of the SnO2 nanowires. Consequently, we do not observe a semiconductor to semimetal transition and band gap narrowing. Instead, the Pb reacts with O2, leading to the deposition of PbO directly on Si but not on the SnO2 nanowires, which have carrier densities of 1016 cm 3. Furthermore, one dimensional growth was completely suppressed by increasing the amount of Pb in Sn. As such, Pb doping of SnO2 and the growth of PbxSn1 xO2 nanowires is difficult, if not impossible, because PbO2 nanowires cannot be grown by the vapor liquid solid mechanism irrespective of the growth temperature. In con.", "author_names": [ "Matthew Zervos", "Andreas Othonos", "Eugenia Tanasa", "Eugeniu Vasile" ], "corpus_id": 197318666, "doc_id": "197318666", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High Temperature Pb Doping of SnO2 and Growth Limitations of PbxSn1 xO2 Nanowires Versus Low Temperature Growth of PbxSn1 xO for Energy Storage and Conversion", "venue": "The Journal of Physical Chemistry C", "year": 2019 }, { "abstract": "Abstract Branched heterostructures play an important role in solar energy harvesting through an efficient separation of photogenerated charges as well as enhancement in catalytic reaction sites. Here we report the CuO/Cu2O nanoflake/nanowire heterostructure with the enhanced surface area directly grown on Cu foil through scalable process steps ensuring easy large scale fabrication. A hydrothermal treatment on Cu2O nanowires, obtained through anodization of Cu foil and argon annealing, leads to a partial conversion of Cu2O into CuO nanoflakes resulting in a heterostructure with a highly enhanced surface area facilitating a higher semiconductor electrolyte interface. Brief annealing at 250 degC for 5 min on the sample results in a photocurrent density of 1.9 mA/cm2 (at 0.3 V vs. Ag/AgCl under AM1.5G illumination) which is about an order of magnitude higher than the Cu2O nanowires. Further, CuO/Cu2O shell/core heterostructure is fabricated through direct annealing of Cu2O nanowires to understand the effect of highly enhanced surface area over the charge separation due to heterostructure. A comparative study on both heterostructures by photocurrent, electrochemical impedance, and Mott Schottky measurements reveals that although CuO/Cu2O heterojunction helps in charge separation, however, the enhanced surface area obtained through nanoflake morphology has a dominating effect in deciding high photocurrent density.", "author_names": [ "Subish John", "Somnath Chanda Roy" ], "corpus_id": 213707908, "doc_id": "213707908", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "CuO/Cu2O nanoflake/nanowire heterostructure photocathode with enhanced surface area for photoelectrochemical solar energy conversion", "venue": "", "year": 2020 } ]

[ { "abstract": "Technology computer aided design (TCAD) semiconductor device simulators solve partial differential equations (PDE) using the finite volume method (FVM) or related methods. While this approach has been in use over several decades, its methods continue to be extended, and are still applicable for investigating novel devices. In this paper, we present an element edge based (EEB) FVM discretization approach suitable for capturing vector field effects. Drawing from a 2D approach in the literature, we have extended this method to 3D. We implemented this method in a TCAD semiconductor device simulator, which uses a generalized PDE (GPDE) approach to simulate de vices with the FVM. We describe how our EEB method is compatible with the GPDE approach, allowing the modeling of vector effects using scripting. This method is applied to solve polarization effects in a 3D ferro capacitor, and a 2D ferroelectric field effect transistor. An example for field dependent mobility in a 3D MOSFET is also presented.", "author_names": [], "corpus_id": 238153151, "doc_id": "238153151", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Element Edge Based Discretization for TCAD Device Simulation", "venue": "IEEE Transactions on Electron Devices", "year": 2021 }, { "abstract": "In this work, the magnitude of the electric field and the deple tion inside a simplified two dimensional model of the ATLAS planar pixel sensor for th e insertable b layer and the super LHC upgrade have been studied. The parameters influen cing the breakdown behavior were studied using a finite element method to solve the drift iffusion equations coupled to Poisson's equation. Using these models, the number of guard rings, dead edge width and sensor's thickness were modified with respect to the ATLAS ac tual pixel sensor to investigate their influence on the sensor's depletion at the edge and on its internal electrical field distribution. The goal of the simulation is to establish a mo del to discriminate between different designs and to select the most optimized to fit the need s in radiation hardness and low material budget of ATLAS inner detector during super LHC op eration. A three defects level model has been implemented in the simulations to study the be avior of such sensors under different level of irradiation. Using the results of our sim ulations, we propose guidelines for the design of future pixel sensor structures and propose test structures to be inserted in a wafer production to verify and calibrate our simulation mod el.", "author_names": [ "A Lounis", "Dominique Martinot", "Giovanni Calderini", "Giovanni Marchiori", "Mathieu Benoit", "Nicoleta Dinu" ], "corpus_id": 115152034, "doc_id": "115152034", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "TCAD Simulation of ATLAS Pixel Guard Ring and Edge Structure for Super LHC Upgrade", "venue": "", "year": 2010 }, { "abstract": "In this work, the magnitude of the electric field and the depletion inside a simplified two dimensional model of the ATLAS planar pixel sensor for the insertable b layer and the super LHC upgrade have been studied. The parameters influencing the breakdown behavior were studied using a finite element method to solve the drift diffusion equations coupled to Poisson's equation. Using these models, the number of guard rings, dead edge width and sensor's thickness were modified with respect to the ATLAS actual pixel sensor to investigate their influence on the sensor's depletion at the edge and on its internal electrical field distribution. The goal of the simulation is to establish a model to discriminate between different designs and to select the most optimized to fit the needs in radiation hardness and low material budget of ATLAS inner detector during super LHC operation. A three defects level model has been implemented in the simulations to study the behavior of such sensors under different level of irradiation. Using the results of our simulations, we propose guidelines for the design of future pixel sensor structures and propose test structures to be inserted in a wafer production to verify and calibrate our simulation model.", "author_names": [ "A Lounis", "Dominique Martinot", "Giovanni Marchiori", "Mathieu Benoit", "Nicoleta Dinu", "Giovanni Calderini" ], "corpus_id": 114367074, "doc_id": "114367074", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "TCAD Simulations of ATLAS Pixel Guard Ring and Edge Structure for SLHC Upgrade", "venue": "", "year": 2010 }, { "abstract": "Two dimensional and three dimensional finite element TCAD simulations have been used to investigate the electrical and charge collection properties of fine pitch 3D sensors. The electrical characteristics were compared to experimental results of non irradiated devices, showing a very good agreement, and also proving the effectiveness of the slim edge termination. The charge collection properties of 3D sensors after irradiation up to the maximum fluence expected at HL LHC have been estimated, confirming the very high radiation tolerance of fine pitch devices. SIMULATION OF 3D PIXEL SENSORS CELLS Deliverable: D7.1", "author_names": [ "V Radulovic" ], "corpus_id": 150382242, "doc_id": "150382242", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "AIDA 2020 Advanced European Infrastructures for Detectors at Accelerators Deliverable Report Simulation of 3 D pixel sensors cells", "venue": "", "year": 2016 }, { "abstract": "Abstract Using finite element simulations with Sentaurus TCAD (Technology Computer Aided Design) software, a progress from simple and classic termination for a Schottky diode to new topology termination has been studied in this paper. A polyimide trench under field plate termination has been used. The efficiency increases from 67% for a simple field plate with optimum parameters up to 97% The maximum electric field in the termination dielectric has been evaluated also. A wide study of the termination geometry has been made in order to extract the optimum parameters in two directions. The first one is to obtain a high efficiency regarding the breakdown voltage, and the second one is to have the minimum electric field peak at the termination edge.", "author_names": [ "Houssam Arbess", "Karine Isoird", "Moustafa Zerarka", "Henri Schneider", "Marie Laure Locatelli", "Dominique Planson" ], "corpus_id": 137444942, "doc_id": "137444942", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "High termination efficiency using polyimide trench for high voltage diamond Schottky diode", "venue": "", "year": 2015 }, { "abstract": "An element edge method is developed for the evaluation of stiffness matrix for the 8 node brick element. Handling of large data leads to take more computational time in finite element analysis. The.", "author_names": [ "Shyjo Johnson", "T Jeyapoovan" ], "corpus_id": 210237439, "doc_id": "210237439", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Evaluation of stiffness matrix in finite element analysis using element edge method for the 8 node brick element", "venue": "", "year": 2019 }, { "abstract": "CMOS scaling became popular among researchers and the semiconductor industry since it provides many advantages like faster speed, higher performance, and increased integration density on a chip. Despite the above advantages, short channel effects are a major concern for planar devices at lower technology nodes which led to the development of multiple gate FETs (MugFET) such as Nanosheet FETs (NSFET) Nanowire FET (NWFET) and FinFET as a replacement for planar MOSFETs. Among all these MugFETs, for sub 7nm technology node, NSFETs are a potential replacement of FinFET and NWFETs due to their high drive current and speed. However, the small channel area and doping profile make these MugFETs more susceptible to Process induced variation. In this thesis, some of these issues are discussed and solutions are proposed. The work presented in this thesis is done using Synopsys Sentaurus TCAD and all the characterization is done using Cascade manual prober along with Keysight B1500 parameter analyzer. In the initial part of the thesis, CMOS FETs are designed and simulated using Sentaurus TCAD to match Semiconductor Laboratory (SCL) CMOS 0.18mm device's physical design and electrical characteristics. Id Vgs of n and p type FETs are measured in linear as well as in the saturation region and finally calibrated using the Sentaurus TCAD model. SOI device's faster speed, resistance to latch up, and immunity against radiation make it preferable over conventional planar devices. PD SOI and FD SOI FETs are also designed to a specific 0.18um CMOS target using a calibrated TCAD model for radiation analysis. MugFETs with small channel area are subject to Line edge roughness (LER) due to process induced variation. LER can result in a high mismatch in FET's electrical characteristics. In this thesis, a 3 D LER model has been taken for the accurate analysis of mismatch in NS and NW FETs electrical characteristics. The mismatch performance of NSFET is investigated and reported for different NS widths. Also, SCE performance parameters, like DIBL (mV) and SS (mV/dec) sensitivity to LER are investigated in this chapter. Moreover, the Junctionless mode devices (JL) are preferred over Inversion mode (IM) devices for nanoscale FETs design due to their simple fabrication process, high drive current, and feasibility of doing short channel length design. However, JL FETs are more susceptible to process induced variation. This thesis also includes a study of matching the performance of inversion (INV) and junctionless (JL) NS/NW FETs devices for 3 D LER. Semiconductor devices are also being widely used in space for various applications, also affected by the presence of Cosmic rays consist of different particles such as heavy ions, neutrons, protons, electrons, alpha particles, and gamma rays. Among these cosmic ray particles, heavy ions cause a change in the state of memory element or temporary circuit failure due to instantaneous transient current spike in devices. In the next part of the thesis, heavy ion induced single event transient (SET) in bulk and SOI NSFET are discussed. Vertically stacked nanosheets are designed and simulated using the inbuilt heavy ion Sentaurus TCAD model. SET current in bulk and SOI NSFETs for different device dimensions are investigated and discussed in this thesis. Also, the effect of the different angles of ion incidence on SET performance is analyzed. SOI NSFETs show a distinct advantage over bulk devices for heavy ion SET. Further, different 3 D SOI MugFETs, such as FinFET, NSFET, and NWFET are simulated for SET due to heavy ion irradiation and compared. Finally, an empirical model is also presented in this thesis to predict the SET current with physical design parameters of MugFETs, and as well as the heavy ion model parameters. Physical design as well as heavy ion parameters, such as nanosheet fin width/ thickness, the diameter of a nanowire, linear energy transfer (LET) angle of incidence, and channel doping are incorporated to accurately predict SET due to heavy ion irradiation on these MugFETs.", "author_names": [], "corpus_id": 232401250, "doc_id": "232401250", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "TCAD Based Modelling of Line Edge Roughness and Radiation Effects in Advanced CMOS Devices", "venue": "", "year": 2021 }, { "abstract": "This paper presents a technique to evaluate the fracture parameters by combining the edge based smoothed finite element method (ESFEM) and the scaled boundary finite element method (SBFEM) A semi analytical solution is sought in the region close to the vicinity of the crack tip using the SBFEM, whilst, the ESFEM is used for the rest of the domain. As both methods satisfy the partition of unity and the compatibility condition, the stiffness matrices obtained from both methods can be assembled as in the conventional finite element method. The stress intensity factors (SIFs) are computed directly from their definition. Numerical examples of linear elastic bodies with cracks are solved without requiring additional post processing techniques. The SIFs computed using the proposed technique are in a good agreement with the reference solutions. A crack propagation study is also carried out with minimal local remeshing to show the robustness of the proposed technique. The maximum circumferential stress criterion is used to predict the direction of propagation.", "author_names": [ "Mahesh Surendran", "A L N Pramod", "Sundararajan Natarajan" ], "corpus_id": 56268229, "doc_id": "56268229", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Evaluation of Fracture Parameters by Coupling the Edge Based Smoothed Finite Element Method and the Scaled Boundary Finite Element Method", "venue": "", "year": 2019 }, { "abstract": "The logical element of matching on the STG DICE cell for a content addressable memory was simulated. The element contains two identical groups of transistors. The TCAD simulation of the 65 nm CMOS element showed the resistance to impacts of single nuclear particles up to 60 MeVxcm2/mg comparing to elements on 6 transistors memory cells. The charge collection from the track of single nuclear particles by only transistors of just one of the two groups doesn't lead to the failure state of the cell. In combinational logic of the element of matching can be short term noise pulses can be registered in the range of the linear energy transfer 20 60 MeVxcm2/mg on the tracks of single nuclear particles.", "author_names": [ "Yu V Katunin", "Vladimir Ya Stenin" ], "corpus_id": 31244677, "doc_id": "31244677", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "TCAD simulation of single event transients in the 65 nm CMOS element of matching for a content addressable memory", "venue": "2017 25th Telecommunication Forum (TELFOR)", "year": 2017 }, { "abstract": "Soil tillage is an energy intensive operation and design improvements that reduce forces have been pursued for many different tools. Due to the high cost of prototyping and testing, computer modelling has been adopted to design tillage equipment. In order to model soil tool interaction two methods namely; finite element method (FEM) and discrete element method (DEM) have been used. Fielke (1994 and 1996) found that for shallow working low rake angle tools the cutting edge geometry of a tillage tool has a major effect on tillage forces and soil movement. FEM modelling of the tests was also carried out in Fielke (1999) In this paper the experimental work of Fielke (1994) was simulated using DEM techniques and the results were compared to both the measured data and FEM predicted results. The results of the study showed that better vertical force prediction was obtained using DEM whereas forward soil movements below the tillage depth were simulated more accurately using FEM. This can be attributed to the larger size of particles used in DEM simulation than needed to pass around the cutting edge. It was also shown that DEM can be used to accurately predict soil failure planes.", "author_names": [ "Mustafa Ucgul", "Chris Saunders", "John M Fielke" ], "corpus_id": 103141960, "doc_id": "103141960", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Comparison of the discrete element and finite element methods to model the interaction of soil and tool cutting edge", "venue": "", "year": 2018 } ]

[ { "abstract": "High quality vanadium dioxide (VO2) thin films have been successfully deposited by pulsed laser deposition without postannealing on (0001) and (1010) sapphire substrates. X ray diffraction reveals that the films are highly oriented with (010) planes parallel to the surface of the substrate. VO2 thin films on (0001) and (1010) substrates show semiconductor to metal transistions with electrical resistance changes as large as 4x104, 105, respectively. Thin films on (1010) substrate have a transition at as low as 55 degC with a hysteresis less than 1 degC. These transition properties are comparable with single crystal VO2.", "author_names": [ "Donghwan Kim", "H S Kwok" ], "corpus_id": 123496311, "doc_id": "123496311", "n_citations": 172, "n_key_citations": 2, "score": 1, "title": "Pulsed laser deposition of VO2 thin films", "venue": "", "year": 1994 }, { "abstract": "For growing high quality epitaxial VO2 thin films, the substrate with suitable lattice parameters is very important if considering the lattice matching. In addition, the thermal conductivity between the substrate and epitaxial film should be also considered. Interestingly, the c plane of hexagonal 6H SiC with high thermal conductivity has a similar lattice structure to the VO2 (010) which enables epitaxial growth of high quality VO2 films on 6H SiC substrates. In the current study, we deposited VO2 thin films directly on 6H SiC (0001) single crystal substrates by pulsed laser deposition (PLD) and systematically investigated the crystal structures and surface morphologies of the films as the function of growth temperature and film thickness. With optimized conditions, the obtained epitaxial VO2 film showed pure monoclinic phase structure and excellent phase transition properties. Across the phase transition from monoclinic structure (M1) to tetragonal rutile structure (R) the VO2/6H SiC (0001) film demonstrated a sharp resistance change up to five orders of magnitude and a narrow hysteresis width of only 3.3 degC.", "author_names": [ "Xiankun Cheng", "Qiang Gao", "Kaifeng Li", "Zhongliang Liu", "Qinzhuang Liu", "Qiangchun Liu", "Yongxing Zhang", "Bing Li" ], "corpus_id": 198910818, "doc_id": "198910818", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Enhanced Phase Transition Properties of VO2 Thin Films on 6H SiC (0001) Substrate Prepared by Pulsed Laser Deposition", "venue": "Nanomaterials", "year": 2019 }, { "abstract": "", "author_names": [ "Zeshan Adeel Umar", "N Ahmed", "Rizwan Ahmed", "Muhammad Adnan Arshad", "M Anwar-ul-Haq", "Tousif Hussain", "Maughal Ahmed Ali Baig" ], "corpus_id": 103668701, "doc_id": "103668701", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Substrate temperature effects on the structural, compositional, and electrical properties of VO2 thin films deposited by pulsed laser deposition", "venue": "", "year": 2018 }, { "abstract": "Microwave switching devices based on the semiconductor metal transition of VO2 thin films were developped on two types of substrates C plane sapphire and SiO2 Si, and in both shunt and series configurations. Under thermal activation, the switches achieved up to 30 40 dB average isolation of the radio frequency rf signal on 500 MHz 35 GHz frequency band with weak insertion losses. These VO2 based switches can be electrically activated with commutation times less than 100 ns, which make them promising candidates for realizing efficient and simple rf switches.", "author_names": [ "Frederic Dumas-Bouchiat", "C Champeaux", "A Catherinot", "Aurelian Crunteanu", "Pierre Blondy" ], "corpus_id": 120039637, "doc_id": "120039637", "n_citations": 90, "n_key_citations": 5, "score": 0, "title": "rf microwave switches based on reversible semiconductor metal transition of VO2 thin films synthesized by pulsed laser deposition", "venue": "", "year": 2007 }, { "abstract": "Abstract Undoped and boron (B) doped VO2 thin films were successfully deposited by pulsed laser deposition. Boron doping enables to drastically reduce the metal insulator transition (MIT) temperature (TMIT) at a rate as large as 31.5 degC/at.%B. As boron doping is interstitial, B atoms can be incorporated in the VO2 matrix without affecting its stoichiometry as demonstrated by the invariability of the valence state of vanadium ions. Therefore, boron doping stands as an efficient strategy to reduce TMIT toward room temperature, while maintaining the contrast of both electrical resistivity and infrared transmittance across the MIT suitable for applications such as smart radiators.", "author_names": [ "Thameur Hajlaoui", "Nicolas Emond", "Christian Quirouette", "Boris Le Drogoff", "Joelle Margot", "Mohamed Chaker" ], "corpus_id": 210803010, "doc_id": "210803010", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Metal insulator transition temperature of boron doped VO2 thin films grown by reactive pulsed laser deposition", "venue": "", "year": 2020 }, { "abstract": "Abstract Vanadium dioxide (VO2) because of its unique metal insulator phase transion around room temperature, has enormous potential for applications in thermochromic, electrochromic, microbolometery, and non volatile switches. However, obtaining phase pure VO2 has been challenging due to its narrow window of thermodynamic stability. Pulsed laser deposition (PLD) is considered to be one of the most promising technique to deposit phase pure VO2 thin films. While optimizing PLD processing parameters, (such as oxygen pressure (PO2) substrate temperature (Ts) laser energy (EL) target substrate distance (dT S) and laser repetition rate (RR) is crucial, and their effects have been reported, the effect of gas flow rate (QO2) has been largely neglected. Since the QO2 and PO2 of the PLD system are intertwined at the outset, most reports are focused only on either QO2 or PO2. We report on the effect of gas flow rate under constant PO2, on the quality of the VO2 thin films. Controlling flow rate affected the resistivity contrast between the metallic and insulator phases, the temperature ranges of the transition, and the width of hysteresis. We anticipate that this study will help set the standard for obtaining high quality VO2 thin films.", "author_names": [ "Syed Asad Manzoor Bukhari", "Sooraj Kumar", "Pawan Kumar", "Sarang P Gumfekar", "Hyun-Joong Chung", "Thomas Thundat", "Ankur Goswami" ], "corpus_id": 225682340, "doc_id": "225682340", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "The effect of oxygen flow rate on metal insulator transition (MIT) characteristics of vanadium dioxide (VO2) thin films by pulsed laser deposition (PLD)", "venue": "", "year": 2020 }, { "abstract": "Abstract The influence of oxygen pressure on the structural and electrical properties of vanadium oxide thin films deposited on glass substrates by pulsed laser deposition, via a 5 nm thick ZnO buffer, was investigated. For the purposes of comparison, VO2 thin films were also deposited on c cut sapphire and glass substrates. During laser ablation of the V metal target, the oxygen pressure was varied between 1.33 and 6.67 Pa at 500 degC, and the interaction and reaction of the VO2 and the ZnO buffer were studied. X ray diffraction studies showed that the VO2 thin film deposited on a c axis oriented ZnO buffer layer under 1.33 Pa oxygen had (020) preferential orientation. However, VO2 thin films deposited under 5.33 and 6.67 Pa were randomly oriented and showed (011) peaks. Crystalline orientation controlled VO2 thin films were prepared without such expensive single crystal substrates as c cut sapphire. The metal insulator transition properties of the VO2/ZnO/glass samples were investigated in terms of electrical conductivity and infrared reflectance with varying temperatures, and the surface composition was investigated by X ray photoelectron spectroscopy.", "author_names": [ "Te-Wei Chiu", "Kazuhiko Tonooka", "Naoto Kikuchi" ], "corpus_id": 96001939, "doc_id": "96001939", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Influence of oxygen pressure on the structural, electrical and optical properties of VO2 thin films deposited on ZnO/glass substrates by pulsed laser deposition", "venue": "", "year": 2010 }, { "abstract": "There are significant challenges accompanied by fabricating a pure crystalline VO2 (M1) thin film with an abrupt metal to insulator phase change properties. Most fabrication methods yield an amorphous VO2 thin film that requires a post annealing process to be converted into crystalline VO2 (M1) Hence, the thickness of VO2 (M1) films produced is very limited. In this work, we report the growth of pure VO2 (M1) crystalline thin films onto a sapphire substrate in an oxygen atmosphere by the femtosecond pulsed laser deposition technique and using vanadium pentoxide (V2O5) as an ablation target. The thin films were deposited at substrate temperatures of 25 degC, 400 degC, and 600 degC, which reveal the crystallized structures of VO2 (M1) without post annealing. The thin film deposited at a substrate temperature of 600 degC exhibits a sharp and an abrupt metal to insulator transition (MIT) at a temperature of 66.0 2.5 degC with nearly four orders of magnitude of the resistivity change (3.5 decades) and a narrow MIT hysteresis width of 3.9 degC. Furthermore, the influence of the substrate temperature, nanoparticle or grain size, and film thickness on the MIT parameters such as sharpness of the transition temperature, hysteresis width, and amplitude are discussed for potential applications of tunable antennas, terahertz planar antennas, and RF microwave switches.", "author_names": [ "Eric Kumi-Barimah", "Dimitris E Anagnostou", "Gin Jose" ], "corpus_id": 225767010, "doc_id": "225767010", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Phase changeable vanadium dioxide (VO2) thin films grown from vanadium pentoxide (V2O5) using femtosecond pulsed laser deposition", "venue": "", "year": 2020 }, { "abstract": "The technique of pulse laser deposition with the separation of plume drops is used to produce VO2 thin films on sapphire(0001) and silicon(111) substrates. It is established that the energy density at the target and the oxygen pressure influence the structural and electrical properties of the films. All of the VO2 crystal films exhibit semiconductor metal transitions with a substantial change in the resistance (by 2 5 orders of magnitude) The transmittance in the range 200 800 nm and reflectance in the range 400 700 nm are studied in the temperature range from 20 to 100degC. The transmittance of the films at wavelengths from 300 to 800 nm shows a jump and hysteresis upon heating and cooling. It is for the first time established that the changes in the transmittance of the film are different in character at different wavelengths and the shape of the temperature hysteresis loop for optical transmittance in the visible and near ultraviolet regions does not in all areas replicate the shape of the hysteresis loop for the resistivity of the VO2 films. The difference in the behavior of the hysteresis curves for the transmittance and resistance is attributed to variations in the absorption of the films under variations in temperature.", "author_names": [ "Oleg Alexeyevic Novodvorsky", "L S Parshina", "Olga D Khramova", "Vladimir Mikhalevsky", "Kirill D Shcherbachev", "Vladislav Ya Panchenko" ], "corpus_id": 98029251, "doc_id": "98029251", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Influence of the conditions of pulsed laser deposition on the structural, electrical, and optical properties of VO2 thin films", "venue": "", "year": 2015 }, { "abstract": "In this contribution, we demonstrate room temperature growth of highly oriented single phase nanocrystalline films of VO 2 (A) on glass substrates using pulsed laser deposition (PLD) technique under high oxygen pressure and small target substrate separation. The structural, morphological, optical, electrical and compositional properties of the deposited thin films have been studied by means of X ray diffraction, atomic force microscopy, spectrophotometry, 04 point probe method and X ray photoelectron spectroscopy, respectively. The plasma under which VO 2 (A) was grown has been analyzed by means of time and space resolved optical emission spectroscopy (OES) and Langmuir probe (LP) techniques. We evidenced a correlation between growth conditions and plasma characteristics. While OES showed that at the deposition distance corresponding to the length of the visible plasma, the plasma species are completely thermalized and characterized by a very low degree of excitation, the LP technique indicated a formation of charged clusters within the gas phase. By combining OES and LP data, a quadruple plasma structure has been shown. The growth of under stoichiometric (comparing to the parent V 2 O 5 target) nanocrystalline VO 2 (A) phase has been attributed to nanoparticle formation in the gas phase under a plasma environment rarefied in oxygen atoms due to the scattering and backscattering effects. This finding opens up the opportunity to grow VO 2 polymorphs at very low temperature by PLD for novel promising new device functionalities.", "author_names": [ "Slimane Lafane", "S Malek", "Jackie J Nel", "Samira Abdelli-Messaci" ], "corpus_id": 230797004, "doc_id": "230797004", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Room temperature and high pressure pulsed laser deposition of nanocrystalline VO2 thin films on glass substrate: plasma and film analyses", "venue": "", "year": 2021 } ]

[ { "abstract": "Load resistance and line voltage impact on electric parameters of power supply circuits used in LED lamps are discussed in this paper. Investigations were performed for two power supplies typically used in CLA25 and CLA60 lamps offered by OSRAM Semiconductor. Measurements were performed for load resistance ranging from 10 O to 10 kO and for the alternating input voltage of line frequency and RMS value ranging from about 10 V to 230 V. The impact of power supplies of LED lamps on deformation of the current drawn from the network was also analysed.", "author_names": [ "Przemyslaw Ptak", "Krzysztof Gorecki", "Janusz Zarebski" ], "corpus_id": 201052433, "doc_id": "201052433", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Power supply circuits used in LED lamps", "venue": "", "year": 2016 }, { "abstract": "LED lamps are widely used in household, nonetheless they are still non linear. Therefore, LEDs need a power supply system to correcting their operation, which introduces nonlinearities into the electrical grid and distortions on waveform. Then analysis and quantification of electrical signals is becoming a key issue. This work presents a spectral analysis of analysis of electric current signal in LEDs lamps which yields a novel collection of characteristics and measures to quantify the waveform quality. In particular, periodogram and Fourier transform are considered. For experiments, two circuits are considered: one that corresponds to the commercial LEDs lamp connected to AC source and another one incorporating a power factor corrector. Experimentally, the usefulness and applicability of proposed characteristics is proved.", "author_names": [ "Diego Hernan Peluffo-Ordonez", "Edgardo Javier Revelo-Fuelagan" ], "corpus_id": 15260160, "doc_id": "15260160", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Novel spectral characteristics of the electrical current waveform to quantifying power quality on LED lamps", "venue": "2014 XIX Symposium on Image, Signal Processing and Artificial Vision", "year": 2014 }, { "abstract": "Today,although the application of high power LED Lamps is more and more popular,the singleLamp working voltage is only about 3. 3 V and with a luminous intensity strongly related to the working current. To make the LED Lamp to work in different voltages,different Controlling Circuits and Controlling ICs emerge as the times require. constant current driving Integrated Circuit Chip QX9910 is widely used in the commercial 220 V power supply system due to its low Power,high control precision,large Tuning Range of Pulse width and low cost,but it still needs to be improved for its imperfect typical application circuit and the resulted seriously heating.", "author_names": [ "Wan Wenjian" ], "corpus_id": 203967977, "doc_id": "203967977", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Improving of IC QX9910 with Constant Current Driving in the Typical Application Circuit of Normal High power LED Lamps", "venue": "", "year": 2014 }, { "abstract": "LED lamps are widely used in household, nonethe less they are still non linear. Therefore, LEDs need a power supply system to correcting their operation, which introduces nonlinearities into the electrical grid and distortions on wave form. Then analysis and quantification of electrical signals is becoming a key issue. This work presents a spectral analysis of analysis of electric current signal in LEDs lamps which yields a novel collection of characteristics and measures to quantify the waveform quality. In particular, periodogram and Fourier transform are considered. For experiments, two circuits are considered: one that corresponds to the commercial LEDs lamp connected to AC source and another one incorporating a power factor corrector. Experimentally, the usefulness and applicability of proposed characteristics is proved.", "author_names": [ "versidad Cooperativa de Colombia", "Ernesto Javier Paspuel Revelo" ], "corpus_id": 112393962, "doc_id": "112393962", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Novel spectral characteristics of the electrical current waveform to quantifying power quality on LED lamps", "venue": "", "year": 2014 }, { "abstract": "The increased popularity of LEDs has challenged LED lighting technology to come up with efficient and cost effective solutions on the design of driver circuits. LED driver circuit uses buck, boost and buck boost converters as switching power a conversion circuit which acts as a constant current source for LED lamps. These converters process a large amount of power during current regulation and hence they are inefficient. In this paper, we propose a highly efficient driver circuit with a fly back converter as current regulator. The fly back converter is placed between the dc source and the LED lamp. It uses only a partial power for current regulation and hence the efficiency is improved. Simulation results of open loop highly efficient LED driver with fly back converter as current regulator is presented in this paper.", "author_names": [ "V T Sreedevi", "V Kamala Devi", "Ahire Akanksha Sunil" ], "corpus_id": 42041560, "doc_id": "42041560", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Analysis and simulation of a single stage power supply for LED lighting", "venue": "2013 International Conference on Green Computing, Communication and Conservation of Energy (ICGCE)", "year": 2013 }, { "abstract": "High power white light emitting diode (LED) has attracted a lot of attention from both industry and academia for its high efficacy, simple to drive, environmentally friendly, and long lifespan. It becomes possible applications to replace the incandescent bulbs and fluorescent lamps in residential, industry and commercial lighting. As a result of light emitting diodes with a save electricity, environmental protection, long life, fast response speed, etc. Future will replace the traditional light emitting components into a new light source, so this study will also be LED lighting for the light source for optical analysis. This paper uses constant current IC circuits to provide the stable forward current for LED and achieve the brightness consistency. Finally, we employ the experiments to validate the characteristics of the lamp developed in this paper.", "author_names": [ "Wen-Bin Lin", "" ], "corpus_id": 115506581, "doc_id": "115506581", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Fabrication of LED Lighting with Uninterruptible Power Supply Function", "venue": "", "year": 2014 }, { "abstract": "The utility model relates to an LED (light emitting diode) illumination power supply and drive control system, which comprises a switch power supply, LED lamps and LED control switches, wherein the switch power supply is arranged inside a distribution box or outside the distribution box; the alternating current input end of the switch power supply is connected with a 220V alternating current power supply through a breaker in the distribution box; the direct current safety voltage output end of the switch power supply is connected with main circuits leading to various rooms; and LED control switches of various rooms and the LED lamps in the rooms are connected to DC+ and DC of the main circuit in series. By using the LED illumination power supply and drive control system provided by the utility model, a potential safety hazard problem and a problem that in the prior art, because the 220V alternating current directly enters into the LED lamp, the drive power supply and the LED lamp are centralized so that heat dissipation is difficult are solved; and moreover, the cost of the LED lamps is lowered. An LED drive controller can perform diming control to the LED lamp on the existing arranged illuminating circuit, thus the popularization of LED illumination under the existing conditions can be prompted.", "author_names": [ "" ], "corpus_id": 69483728, "doc_id": "69483728", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "LED (light emitting diode) illumination power supply and drive control system", "venue": "", "year": 2011 }, { "abstract": "The invention provides an LED drive circuit and a power supply circuit and an LED lamp thereof, which are suitable for the field of LED lamps. The power supply circuit of the LED drive circuit comprises a transient power supply unit and a steady state power supply unit. In the embodiment of the invention, the transient power supply unit supplies power to a PFC (Power Factor Correction) control circuit and a PWM (Pulse Width Modulation) control circuit by utilizing voltage output by the rectifier bridge of the LED drive circuit, whereas the steady state power supply unit supplies power to the PFC control circuit and the PWM control circuit by utilizing voltage output by the transformer of the LED drive circuit. The power supply circuit has simple structure and low cost, and when the rectifier bridge does not have output, the power supply circuit stops supplying power to the control circuits, and thereby, the electric energy is greatly saved.", "author_names": [ "" ], "corpus_id": 116025496, "doc_id": "116025496", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "LED (light emitting diode) drive circuit and power supply circuit and LED lamp thereof", "venue": "", "year": 2010 }, { "abstract": "The present invention is applicable to the field of LED lighting, there is provided a power anti reverse circuit, LED lamps and LED lighting circuits, power supply circuit includes an anti reverse switching device and a bias voltage module. In the present invention, the anti reverse power supply circuit using MOS transistor as a switching device, when the power is reversed, the use of the switching characteristics of MOS tube LED lamps disconnect the power path of the circuit, and thus play a role in anti reverse power, and due to the small MOS tube resistance, low pressure drop, so its small power consumption.", "author_names": [ "" ], "corpus_id": 115866122, "doc_id": "115866122", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Circuit for preventing reverse connection of power supply, LED lamp circuit and LED lamp", "venue": "", "year": 2010 }, { "abstract": "This paper presents input EMI filter and damping circuits for phase dimmable LED lamps. An input EMI filter is implemented as part of LED lamp power supplies to comply with conducted emission standards set by regulatory agencies. The use of conventional EMI filter configurations are limited in this application due to the absence of earth (chassis) connection and the presence of stringent mechanical size constraints. This paper describes alternative EMI filter topologies suitable for 2 wire input connections present in Edison or Bayonet sockets. Criteria for achieving dimmer compatibility are introduced and the impact of an EMI filter on phase dimming operation is studied. The influence of different damping networks on transient performance of systems is analyzed using pole zero mapping techniques and minimum damping requirements are established. A step by step procedure for EMI filter and damping network design is outlined and verified for a 16 W, 230 VAC LED power supply example based on a discontinuous conduction mode (DCM) Flyback topology.", "author_names": [ "Montu Doshi", "James Patterson" ], "corpus_id": 19287865, "doc_id": "19287865", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Input filter design for TRIAC dimmable LED lamps", "venue": "2013 IEEE Energy Conversion Congress and Exposition", "year": 2013 } ]

[ { "abstract": "We have successfully improved the scaling of Cu Cu hybrid bonding. In this study, 3 \\mu \\mathrm{ m} pitch and 3M Cu Cu connections with sufficient electrical properties and reliabilities were achieved. The ultra fine pitch Cu Cu connections correspond to the 0.75x scaling of conventional Cu Cu hybrid bonding that we previously reported. Our high density 3D chip stacking technology is expected to enhance not only the function of back illuminated CMOS image sensors (BI CIS) but also that of coming 3D stacked semiconductor devices.", "author_names": [ "Yoshihisa Kagawa", "Shogo Hida", "Y Kobayashi", "Keishi Takahashi", "Shunichi Miyanomae", "M Kawamura", "Hiroshi Kawashima", "H Yamagishi", "Tomoyuki Hirano", "Keiji Tatani", "H Nakayama", "K Ohno", "Hayato Iwamoto", "S Kadomura" ], "corpus_id": 174820181, "doc_id": "174820181", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "The Scaling of Cu Cu Hybrid Bonding For High Density 3D Chip Stacking", "venue": "2019 Electron Devices Technology and Manufacturing Conference (EDTM)", "year": 2019 }, { "abstract": "Abstract Due to the advantages of small form factor, high performance, low power consumption, and high density integration, three dimensional integrated circuits (3D ICs) have been generally acknowledged as the next generation semiconductor technology. Low temperature bonding is the key technology to ensure the chip (or wafer) stacking in 3D ICs. In this paper, different low temperature bonding methods for chip (or wafer) stacking were reviewed and described systematically. Materials, processing and reliability will be extremely important, their effects on the 3D IC structure were addressed in detail, the challenging reliability issues may be considered as the major concern in the future work. The latest development of low temperature bonding in 3D ICs is also given here, which helpful may provide a reference for the further study of low temperature bonding.", "author_names": [ "Zhang Liang", "Zhi-Quan Liu", "Sinn-wen Chen", "Yao-dong Wang", "Wei-min Long", "Guo Yonghuan", "Song Wang", "G Ye", "Wen-yi Liu" ], "corpus_id": 116364894, "doc_id": "116364894", "n_citations": 42, "n_key_citations": 0, "score": 0, "title": "Materials, processing and reliability of low temperature bonding in 3D chip stacking", "venue": "", "year": 2018 }, { "abstract": "3D chip stacking with through silicon vias (TSVs) has been identified as one of the major technologies for achieving higher silicon packaging density and shorter interconnect. The test vehicle presented in this paper is a 3D chip stack package. Each layer of the test vehicle has two silicon flip chips mounted at the bottom of a silicon interposer with solder bumps. The flip chip has the equivalent dimensions and pad patterns as commercial memory chips. The interposer, with multiple interconnect TSVs for electrical connection and a central TSV for underfill dispensing, can function as a logic chip or as a redistribution chip in a real application. The assembly steps of the test vehicle include conductive adhesive filling for the interconnect TSVs, bonding two bumped flip chips on an interposer (to form a single layer) vertical stacking of the single layers and underfill dispensing. For the filling of the interconnect TSVs, an auger dispensing method is first adopted to overfill the interconnect TSVs, followed by removing the excessive adhesive beyond the interconnect TSVs by squeegeeing. A jet valve continuously dispenses free dots of an underfill encapsulant into the central TSVs. The central TSVs function as an entrance for underfill dispensing and an uninterrupted point source to provide fluid for each layer. The free dots form a capillary flow to fill the under chip spaces of the test vehicle. The usage of TSVs rather than chip edges eliminates the presence of a wide edge reservoir, resulting in smaller 'keep out' area occupation on the substrate.", "author_names": [ "Fuliang Le", "Shi Wei Ricky Lee", "Qiming Zhang" ], "corpus_id": 115118690, "doc_id": "115118690", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "3D chip stacking with through silicon vias (TSVs) for vertical interconnect and underfill dispensing", "venue": "", "year": 2017 }, { "abstract": "This article consists of a collection of slides from the author's conference presentation on low cost 3D chip stacking with ThruChip's wireless connections. Some of the specific topics discussed include: the challenges of current 3D stacking methods; the deployment of wireless technologies from a cost and bandwidth perspective; advancements in wafer thinning; stacked wireless data communication; and power distribution facilities.", "author_names": [ "David R Ditzel" ], "corpus_id": 8496387, "doc_id": "8496387", "n_citations": 28, "n_key_citations": 7, "score": 0, "title": "Low cost 3D chip stacking with ThruChip wireless connections", "venue": "2014 IEEE Hot Chips 26 Symposium (HCS)", "year": 2014 }, { "abstract": "Abstract The study aims at assessing the growth reaction of the Ni3Sn4 intermetallic compound (IMC) during bonding process and its dependences on the thermal cycling reliability of the Cu/Ni/SnAg micro joints of an advanced 3D chip stacking package under accelerated thermal cycling (ATC) loading. The growth reaction of the IMC during bonding process is also predicted through experiment and classical diffusion theory, and the relation between the IMC thickness and bonding process temperature and time is derived according to the predicted activation energy of the chemical reaction between Sn and Ni by experiment. Moreover, the micro joint reliability prediction is made using finite element (FE) analysis incorporated with an empirical Coffin Manson fatigue life prediction model and also ATC experimental test. To facilitate the FE modeling, the temperature dependent thermoelastic properties of both single crystal and polycrystalline Ni3Sn4 IMC are characterized through molecular dynamics simulation and the Voigt Reuss bound and Voigt Reuss Hill approximation. Results show that monoclinic single crystal Ni3Sn4 reveals a high elastic anisotropy or direction dependence of elasticity. The diffusion reaction of Sn and Ni exhibits that a longer bonding process time and a higher bonding temperature could not only increase the IMC thickness but also vary its surface morphology. In addition, the thermal mechanical performance of the micro joints is strongly affected by the geometry and material of IMC layer, where IMC with a thicker thickness, a less Young's modulus, a smaller CTE and even a more rounded surface morphology can better the reliability.", "author_names": [ "Wen-Hwa Chen", "Ching-Feng Yu", "Hsien-Chie Cheng", "Yu-min Tsai", "Su-Tsai Lu" ], "corpus_id": 33239856, "doc_id": "33239856", "n_citations": 54, "n_key_citations": 0, "score": 0, "title": "IMC growth reaction and its effects on solder joint thermal cycling reliability of 3D chip stacking packaging", "venue": "Microelectron. Reliab.", "year": 2013 }, { "abstract": "With the impressive size shrinkage of advanced transistors and Cu/low k interconnect systems, the introduction of through silicon via integrated with three dimensional (3D) chip stacking approaches has become one of the major packaging technologies to meet the desired requirements of multifunctionality. The use of microbump @m bump) interconnected silicon chips to ensure the reliability of the interconnections is regarded as a critical issue that must be resolved. In this research, wafer level underfill (WLUF) joined with flip chip technology are proposed, and a nonlinear finite element analysis, combined with a process oriented simulation technique, is used to investigate the packaging assembly effect of the WLUF thermal compressive process. The stress predictions during the temperature cycling test is also systematically explored. The proposed simulation methodology is successfully validated through comparison with experimental data. The analytical results indicate that both the assembly and thermomechanical reliabilities of @m bumps are determined by the arrangement of the @m bump arrays. Consequently, the optimal designs of @m bump layouts within the chips must be seriously considered, given that silicon chips thinner than 100@mm are assembled in 3D advanced packages.", "author_names": [ "Chang-Chun Lee", "Tsung-Fu Yang", "Chih-Sheng Wu", "Kuo-shu Kao", "Ren-Chin Cheng", "Tai-Hong Chen" ], "corpus_id": 109947640, "doc_id": "109947640", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Reliability estimation and failure mode prediction for 3D chip stacking package with the application of wafer level underfill", "venue": "", "year": 2013 }, { "abstract": "The misalignment effect in three dimensional (3D) chip packages is studied numerically using the finite element method (FEM) The model features a through silicon via (TSV)/micro bump bonding structure connecting two adjacent silicon (Si) chips, with and without surrounding underfill. Misalignment is implemented through a prescribed shear deformation, and we seek to parametrically explore the trend of stress and deformation fields as affected by the geometry and material. Different solder thicknesses in the micro bump, as well as a special case where the entire solder region is transformed into the intermetallic compound, are considered in this study. The effects of shear deformation are also compared with those due to thermal expansion mismatch. A thinner solder region in the micro bump is found to have a higher propensity of damage initiation. The existence of underfill enhances the resistance to overall shear deformation, although with a much greater buildup of local stresses. With an intermetallic layer in place of the soft solder alloy in the micro bump, the overall shear strength of the structure increases but with a concomitant increase in the risk of local brittle failure.", "author_names": [ "Y -L Shen", "R Wayne Johnson" ], "corpus_id": 17506366, "doc_id": "17506366", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "Misalignment induced shear deformation in 3D chip stacking: A parametric numerical assessment", "venue": "Microelectron. Reliab.", "year": 2013 }, { "abstract": "3D integration, using fine pitch and high density vertical interconnects (TSVs) has been drawing considerable interest due to its promise for higher performance and smaller form factor. As the number of I/O increases and the pitch size decreases, interconnect joining process and reliability become critical in the assembly of 3D chip stacks. In this study, 3D chip stacks with more than 48,000 Pb free solder micro bump interconnects at 50 mm pitch were assembled and the joint reliability evaluated. Multiple bonding processes were developed, enhanced and characterized by investigating the influence of various bonding parameters such as atmosphere, compression mode and temperature profile on the joint formation. Various test vehicle sizes with multiple layers of thinned die were successfully assembled using the enhanced bonding profile. Underfilling of the narrow gaps between the stack dies was demonstrated using underfills with fine particle fillers. The assembly yield and interconnection parasitic resistance was quantitatively studied as a function of the number of die layers. The reliability silicon die stacks integrated into modules with organic laminates was characterized by thermal cycling tests.", "author_names": [ "J Maria", "Bing Dang", "Steven L Wright", "Cornelia K Tsang", "Paul S Andry", "Robert J Polastre", "Yong Liu", "L Wiggins", "John U Knickerbocker" ], "corpus_id": 29266758, "doc_id": "29266758", "n_citations": 38, "n_key_citations": 3, "score": 0, "title": "3D Chip stacking with 50 mm pitch lead free micro c4 interconnections", "venue": "2011 IEEE 61st Electronic Components and Technology Conference (ECTC)", "year": 2011 }, { "abstract": "Recently, the three dimensional chip stacking technology with fine pitch and high input/output interconnects has emerged due to the requirements of multi function and high performance in electronic devices. When the electronic packaging technology develops toward the miniaturization trend, the reliability of interconnect with fine pitch and high density solder bump interconnections will become a critical issue in advanced 3D chip stacking technology. In this study, assembly of chip on chip test vehicle with a micro bump pitch of 30 um was demonstrated and the joint reliability was also evaluated. The Si chip/carrier used in this study had more than 3000 micro bumps with Sn2.5Ag solder material. Ni/Cu under bump metallurgy layer (UBM) was selected on both the top and bottom chip. 3D chip stacking was achieved by thermo bonding and subsequently underfill dispensing for fine gap filling was also conducted with different kinds of underfills. The temperature cycling test was performed on the chip on chip stacking module over 1000 cycles. In addition, with the joint size becoming small, the current for each solder bump carried continues to increase. This leads high current flowing in each individual joint. Therefore, electromigration has become a major reliability issue in microelectronic devices. In this study, electromigration in SnAg solder micro bump with a pitch of 30 mm was investigated under 0.12A at 135degC. Electromigration characteristics of fine pitch micro bump was discussed with the microstructure evolution of micro bump during current stressing. The assembly of 3D stacking chip using two layers of chip with fine pitch and lead free interconnects was achieved in this study. The results of reliability test showed that the reliability of fine pitch solder micro bump interconnections was acceptable under mechanical and electrical evaluations.", "author_names": [ "Chau-Jie Zhan", "Chun-Chih Chuang", "Jin-Ye Juang", "Su-Tsai Lu", "Tao-Chih Chang" ], "corpus_id": 38258886, "doc_id": "38258886", "n_citations": 41, "n_key_citations": 1, "score": 0, "title": "Assembly and reliability characterization of 3D chip stacking with 30mm pitch lead free solder micro bump interconnection", "venue": "2010 Proceedings 60th Electronic Components and Technology Conference (ECTC)", "year": 2010 }, { "abstract": "Due to the raising requirements of functionality and performance in consumer electronics, high density package technology including high I/O interconnections and 3D chip stacking technology have received a great number of attentions. Solder micro bumps are widely applied in high density interconnections packaging, but its bonding temperature is still high during process. During chip stacking process, high bonding temperature would lead chip damage and chip warpage induced by the mismatch of coefficient of thermal expansion among each structure within the chip. Also, warpage would cause stress concentration happened within the chip and damage the device and micro interconnections. In order to meet the purpose of low temperature bonding, we demonstrated the chip to chip stacking module with a bump pitch of 30um by using non conductive film in this study. The reliability of the chip stacking module produced by such low temperature bonding approach was also estimated. A chip on chip (COC) structure was used as the test vehicles. There were about 3000 bumps totally in this test vehicle. For evaluating the feasibility of adhesive bonding by NCF in fine pitch micro bumps, Cu/Ni/Au micro bumps joined with Cu/Sn solder micro bumps was conducted by using NCF in this study. After assembly process, thermal cycling test, thermal humidity storage test and high current test were carried out to evaluate the reliability performance of the micro interconnections by such low temperature bonding approach. In this investigation, the chip on chip stacking module with a bump pitch of 30mm by using non conductive film was achieved. The bonding results revealed that the contact resistance of micro joints was about 100 350 MO. The high deviation of contact resistance was due to the non melting contact between joined micro bump by soft tin solder. The reliability results revealed that the chip stacking module produced by NCF could pass the reliability test of 1000 cycles of TCT and 1000 hours of THST. The results of high current test also showed that the NCF joint had excellence endurance against high current density of 5x104 A/cm2 for more than 1300 hours with an increase of contact resistance less than 2% This study displayed that the NCF material had great potential to be applied in fine pitch 3D chip stacking. The multi chip stacking module with a TSV pitch of 20mm produced by NCF will also be presented in this investigation.", "author_names": [ "Yu-Min Lin", "Chau-Jie Zhan", "Kuo-shu Kao", "Chia-Wen Fan", "Su-Ching Chung", "Yu-wei Huang", "Shin-Yi Huang", "Jing-Yao Chang", "Tsung-Fu Yang", "John H Lau", "Tai-Hung Chen" ], "corpus_id": 2263904, "doc_id": "2263904", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Low temperature bonding using non conductive adhesive for 3D chip stacking with 30mm pitch micro solder bump interconnections", "venue": "2012 IEEE 62nd Electronic Components and Technology Conference", "year": 2012 } ]

[ { "abstract": "Exploring two dimensional (2D) crystals with intrinsic room temperature magnetism is of particular importance to develop practical spintronics applications at the nanoscale. Here, we report the electronic and magnetic properties of a freestanding 2D NbS2 crystal on the basis of first principles calculations. Our results demonstrate that the 2D NbS2 monolayer is a bipolar magnetic semiconductor with a spin bandgap of 0.27 eV by using the screened hybrid density functional HSE06 method. In particular, both electron and hole doping could induce the transition from a bipolar magnetic semiconductor to a half metal in NbS2 nanosheets, where the spin polarization direction of carriers in half metallic NbS2 nanosheets can be tuned with the doping type. The Monte Carlo simulation predicts a Curie temperature of over 141 K in the 2D NbS2 crystal, which can be enhanced up to 273 K by hole doping or applying a biaxial tensile strain. These findings imply the great potential of 2D NbS2 nanosheets in nanoscale spintronics applications.", "author_names": [ "Ying-jie Sun", "Zhiwen Zhuo", "Xiaojun Wu" ], "corpus_id": 139403052, "doc_id": "139403052", "n_citations": 16, "n_key_citations": 0, "score": 1, "title": "Bipolar magnetism in a two dimensional NbS2 semiconductor with high Curie temperature", "venue": "", "year": 2018 }, { "abstract": "Lithium sulfur batteries practically suffer from short cycling life, low sulfur utilization, and safety concerns, particularly at ultrahigh rates and high sulfur loading. To address these problems, we have designed and synthesized a ternary NbS2@S@IG composite consisting of sandwich type NbS2@S enveloped by iodine doped graphene (IG) The sandwich type structure provides an interconnected conductive network and plane to point intimate contact between layered NbS2 (or IG) and sulfur particles, enabling sulfur species to be efficiently entrapped and utilized at ultrahigh rates, while the structural integrity is well maintained. NbS2@S@IG exhibits prominent high power charge/discharge performances. Reversible capacities of 195, 107, and 74 mA h g 1 (1.05 mg cm 2) have been achieved after 2000 cycles at ultrahigh rates of 20, 30, and 40 C, respectively, and the corresponding average decay rates per cycle are 0.022% 0.031% and 0.033% respectively. When the area sulfur loading is increased to 3.25 mg cm 2, the electrode still maintains a high discharge capacity of 405 mAh g 1 after 600 cycles at 1 C. Three half cells in series assembled with NbS2@S@IG can drive 60 indicators of LED modules after only 18 s of charging. The instantaneous current and power of the device reach 196.9 A g 1 and 1369.7 W g 1, respectively.", "author_names": [ "Zhubing Xiao", "Zhi Yang", "Linjie Zhang", "Hui Pan", "Ruihu Wang" ], "corpus_id": 206713730, "doc_id": "206713730", "n_citations": 115, "n_key_citations": 0, "score": 1, "title": "Sandwich Type NbS2@S@I Doped Graphene for High Sulfur Loaded, Ultrahigh Rate, and Long Life Lithium Sulfur Batteries.", "venue": "ACS nano", "year": 2017 }, { "abstract": "Despite intense efforts on all known quasi two dimensional superconductors, the origin and exact boundary of the electronic orderings, particularly charge density waves and superconductivity, are still attractive problems with several open questions. Here, in order to reveal how the superconducting gap evolves, we report on high quality complementary measurements of magneto optical imaging, specific heat, magnetic susceptibility, resistivity measurements, Andreev spectroscopy, and London penetration depth \\ensuremath{\\lambda}}_{ab}(T) measurements supplemented with theoretical calculations for $2\\mathrm{H}\\text{\\ensuremath{ \\mathrm{Nb}\\mathrm{Se}}_{2} and $2\\mathrm{H}\\text{\\ensuremath{ \\mathrm{Nb}\\mathrm{S}}_{2} single crystals. The temperature dependence of \\ensuremath{\\lambda}}_{ab}(T) calculated from the lower critical field and Andreev spectroscopy can be well described by using a two band model with $s$ wave like gaps. The effect of pressure on the superconducting gap of both systems illustrates that both bands are practically affected. Upon compression, the Fermi surfaces do not change significantly, and the nesting remains almost unaffected compared to that at ambient condition. However, a strong bending in the upper critical fields {H}_{\\mathrm{c}2} curves is obtained under pressure and support the presence of a strong Pauli paramagnetic effect. In \\mathrm{Nb}\\mathrm{Se}}_{2} using a two band model with $s$ wave like gaps, the temperature dependence {H}_{\\mathrm{c}2}(T) can be properly described. In contrast to that, the behavior of {H}_{\\mathrm{c}2} for \\mathrm{Nb}\\mathrm{S}}_{2} is ruled by the spin paramagnetic effect. The estimated values of the penetration depth at $T=0\\phantom{\\rule{0.16em}{0ex}\\mathrm{K} confirm that \\mathrm{Nb}\\mathrm{Se}}_{2} and \\mathrm{Nb}\\mathrm{S}}_{2} superconductors depart from a Uemura style relationship between {T}_{\\mathrm{c} with \\mathbit{\\ensuremath{\\lambda}}_{ab}\\ensuremath{ }2}(T) the in plane superconducting penetration depth.", "author_names": [ "Arnab Majumdar", "Derrick VanGennep", "Jeremy Brisbois", "Dmitriy A Chareev", "Andrey V Sadakov", "A S Usoltsev", "M Mito", "Alejandro V Silhanek", "Tapati Sarkar", "Abdelwahab Hassan", "Olof Karis", "Rajeev Ahuja", "Mahmoud M Abdel-Hafiez" ], "corpus_id": 225271579, "doc_id": "225271579", "n_citations": 15, "n_key_citations": 0, "score": 2, "title": "Interplay of charge density wave and multiband superconductivity in layered quasi two dimensional materials: The case of 2H NbS2 and 2H NbSe2", "venue": "Physical Review Materials", "year": 2020 }, { "abstract": "In all known Group 5 transition metal dichalcogenide monolayers (MLs) the metal centers carry a spin, and their ground state phases are either metallic or semiconducting with indirect band gaps. Here, on grounds of first principles calculations, we report that the Haeckelite polytypes 1S NbX2 (X=S, Se, Te) are diamagnetic direct band gap semiconductors even though the Nb atoms are in the 4+ oxidation state. In contrast, 1S VX2 MLs are antiferromagnetically coupled indirect band gap semiconductors. The 1S phases are thermodynamically and dynamically stable but of slightly higher energy than their 1H and 1T ML counterparts. 1S NbX2 MLs are excellent candidates for optoelectronic applications owing to their small band gaps (between 0.5 and 1 eV) Moreover, 1S NbS2 shows a particularly high hole mobility of 2.68x103 cm2 V 1 s 1 which is significantly higher than that of MoS2 and comparable to that of WSe2", "author_names": [ "Yandong Ma", "Agnieszka Beata Kuc", "Yu Jing", "Pierre Herman Theodoor Philipsen", "Thomas Heine" ], "corpus_id": 19694719, "doc_id": "19694719", "n_citations": 20, "n_key_citations": 0, "score": 1, "title": "Two Dimensional Haeckelite NbS2 A Diamagnetic High Mobility Semiconductor with Nb4+ Ions.", "venue": "Angewandte Chemie", "year": 2017 }, { "abstract": "Two dimensional (2D) heterostructures based on layered transition metal dichalcogenides (TMDs) have attracted increasing attention for the applications of the next generation high performance integrated electronics and optoelectronics. Although various TMD heterostructures have been successfully fabricated, epitaxial growth of such atomically thin metal semiconductor heterostructures with a clean and sharp interface is still challenging. In addition, photodetectors based on such heterostructures have seldom been studied. Here, we report the synthesis of high quality vertical NbS2/MoS2 metallic semiconductor heterostructures. By using NbS2 as the contact electrodes, the field effect mobility and current on off ratio of MoS2 can be improved at least 6 fold and two orders of magnitude compared with the conventional Ti/Au contact, respectively. By using NbS2 as contact, the photodetector performance of MoS2 is much improved with higher responsivity and less response time. Such facile synthesis of atomically thin metal semiconductor heterostructures by a simple chemical vapor deposition strategy and its effectiveness as ultrathin 2D metal contact open the door for the future application of electronics and optoelectronics.", "author_names": [ "P Zhang", "Ce Bian", "Jiafu Ye", "Ningyan Cheng", "Xiao Wang", "Huaning Jiang", "Yi Wei", "Yiwei Zhang", "Yi Du", "Lihong Bao", "Weida Hu", "Yongji Gong" ], "corpus_id": 220071773, "doc_id": "220071773", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "Epitaxial growth of metal semiconductor van der Waals heterostructures NbS2/MoS2 with enhanced performance of transistors and photodetectors", "venue": "Science China Materials", "year": 2020 }, { "abstract": "The relatively high recombination rate of charges remains the most critical limiting factor for solar driven water splitting for hydrogen generation. Herein, a tandem 0D/2D/2D NbS2 quantum dot/Nb2 O5 nanosheet/g C3 N4 flake (NSNOCN) system is designed. Owing to the unique spatial arrangement and elaborate morphology of 0D NbS2 2D Nb2 O5 and 2D g C3 N4 in the newly designed NSNOCN, plenty of spatial charge transfer cascades from g C3 N4 to NbS2 via Nb2 O5 are formed to accelerate separation and transfer of charges significantly, thus contributing to a high photocatalytic H2 generation rate of 13.99 mmol h 1 g 1 (an apparent quantum efficiency of 10.8% at 420 nm) up to 107.6 and 43.7 times by contrast with that of g C3 N4 and Nb2 O5 respectively. This work can provide a new platform in the design of artificial photocatalytic systems with high charge transfer efficiency.", "author_names": [ "Bo Lin", "Zihao Chen", "Pin Song", "Haishi Liu", "Lixing Kang", "Jun Di", "Xiao Luo", "Longqing Chen", "Chao Xue", "Bowen Ma", "Guidong Yang", "Jun Tang", "Jiadong Zhou", "Zheng Liu", "Fucai Liu" ], "corpus_id": 221883871, "doc_id": "221883871", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "A Tandem 0D/2D/2D NbS2 Quantum Dot/Nb2 O5 Nanosheet/g C3 N4 Flake System with Spatial Charge Transfer Cascades for Boosting Photocatalytic Hydrogen Evolution.", "venue": "Small", "year": 2020 }, { "abstract": "There is an urgent need to develop efficient and nonprecious electrode materials for practical electrocatalyst hydrogen evolution reaction (HER) application to restrain the depletion of fossil fuels. In the present work, we report an efficient and cost effective electrode with high stability for binder free water electrolysis under all ranges of pH from 0 to 14. Herein, a two dimensional (2D) heterostructure of NbS2/MoS2 ultrathin vertical nanosheets was grown on carbon nanofiber with a high aspect ratio by the one step chemical vapor deposition approach. The resultant hybrid catalyst demonstrates superlative HER performance with a small onset potential (41 mV 0 pH, 22 mV 7 pH and 32 mV 14 pH) and a very low overpotential (0.23 V 0 pH, 0.21 V 7 pH and 0.33 V 14 pH to reach 50 mA/cm2) vs reversible hydrogen electrode (RHE) Besides, the fabricated NbS2/MoS2 CNF displays excellent chronoamperometry stability for more than 50 h in all pH ranges. The proposed heterostructure holds the vital prerequisites for being a significant electrode material owing to multiple HER active edge and planar sulfur sites, excellent barrier free charge transfer ability toward the electrolyte, and impressive endurance. Overall, the 2D/one dimensional (1D) hybrid heterostructure appeared to be a precious metal free flexible electrode for excellent HER performance under wide ranges of pH for water splitting applications.", "author_names": [ "Paulraj Gnanasekar", "Kugalur Shanmugam Ranjith", "Palanisamy Manivel", "Young-Kyu Han", "Jeganathan Kulandaivel" ], "corpus_id": 225674385, "doc_id": "225674385", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Hierarchical NbS2/MoS2 Carbon Nanofiber Electrode for Highly Efficient and Stable Hydrogen Evolution Reaction at All Ranges of pH", "venue": "", "year": 2020 }, { "abstract": "We present magnetic torque, specific heat and thermal expansion measurements combined with a piezo rotary positioner of the bulk transition metal dichalcogenide (TMD) superconductor NbS2 in high magnetic fields applied strictly parallel to its layer structure. The upper critical field of superconducting TMDs in the 2D form is known to be dramatically enhanced by a special form of Ising spin orbit coupling. This Ising superconductivity is very robust against the Pauli limit for superconductivity. We find that superconductivity beyond the Pauli limit still exists in bulk single crystals of NbS2. However, the comparison of our upper critical field transition line with numerical simulations rather points to the development of a Fulde Ferrell Larkin Ovchinnikov state above the Pauli limit as a cause. This is also consistent with the observation of a magnetic field driven phase transition in the thermodynamic quantities within the superconducting state near the Pauli limit.", "author_names": [ "Chang-Woo Cho", "Jian Lyu", "Cheuk Yin Ng", "James Jun He", "T A Abdel-Baset", "Mahmoud M Abdel-Hafiez", "Rolf Lortz" ], "corpus_id": 226289667, "doc_id": "226289667", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Superconductivity beyond Pauli's limit in bulk NbS2: Evidence for the Fulde Ferrell Larkin Ovchinnikov state", "venue": "", "year": 2020 }, { "abstract": "The understanding of the nonlinear optical (NLO) properties of photonic materials is relevant and necessary for basic studies and technological developments. Among the materials with high optical n.", "author_names": [ "Melissa Maldonado", "Manoel L da Silva Neto", "Pilar Gregory Vianna", "Henrique B Ribeiro", "Vanessa Orsi Gordo", "Isabel C S Carvalho", "Leonardo de S Menezes", "Cid B de Araujo", "Christiano J S de Matos", "Leandro Seixas", "Ali Jawaid", "Robert Busch", "Allyson J Ritter", "Richard A Vaia", "Anderson S L Gomes" ], "corpus_id": 225786781, "doc_id": "225786781", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Femtosecond Nonlinear Optical Properties of 2D Metallic NbS2 in the Near Infrared", "venue": "", "year": 2020 }, { "abstract": "In recent days, 2 dimensional (2D) niobium disulphide (NbS2) with the near zero Gibbs free energy and superlative acid electrolyte stability has provoked a great deal of interest towards hydrogen evolution reaction (HER) electrocata lyst due to its active basal and edge sulphur sites. Here in, we developed a single step method for the direct deposition of 2D NbS2 on high aspect ratio topographies of silicon nanowires (NWs) by chemical vapor deposition for the appli cations in HER electrocatalyst. The resultant 2D NbS2 electrocatalyst demonstrates the HER overpotential of ~74mV vs. RHE (reversible hydrogen electrode) 1 mA/cm2 under acidic conditions and stable for more than 20 hours. More importantly, we developed the Si NWs array based photoelectrochemical water splitting system with the direct deposi tion of 2D NbS2 as HER catalyst. The resultant 2D NbS2 Si NWs photocathode system demonstrates improved charge transfer characteristics at the Si NbS2 interfaces that leads to an enhanced turn on potential (from 0.06 V to 0.34 V vs. RHE) with the current density of 28 mA/cm2 at the 0 V vs. RHE. The results evidence the synergistic effect of 2D NbS2 electrocatalysts that addresses poor surface kinetics of Si towards solar water electrolysis. Our comprehensive studies reveal that NbS2 as a new class of photoelectrochemical co catalyst for efficient solar HER performance by promoting the charge transfer process with prolonged acid stability.", "author_names": [ "Paulraj Gnanasekar", "Dharmaraj Periyanagounder", "Purushothaman Varadhan", "Jr-hau He", "Jeganathan Kulandaivel" ], "corpus_id": 207894714, "doc_id": "207894714", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Highly efficient and stable photoelectrochemical hydrogen evolution with 2D NbS2 /Si nanowire heterojunction.", "venue": "ACS applied materials interfaces", "year": 2019 } ]

[ { "abstract": "Lead halide perovskite semiconductors have recently gained wide interest following their successful embodiment in solid state photovoltaic devices with impressive power conversion efficiencies, while offering a relatively simple and low cost processability. Although the primary optoelectronic properties of these materials have already met the requirement for high efficiency optoelectronic technologies, industrial scale up requires more robust processing methods, as well as solvents that are less toxic than the ones that have been commonly used so successfully on the lab scale. Here we report a fast, room temperature synthesis of inks based on CsPbBr3 perovskite nanocrystals using short, low boiling point ligands and environmentally friendly solvents. Requiring no lengthy post synthesis treatments, the inks are directly used to fabricate films of high optoelectronic quality, exhibiting photoluminescence quantum yields higher than 30% and an amplified spontaneous emission threshold as low as 1.5 mJ cm 2. Finally, we demonstrate the fabrication of perovskite nanocrystal based solar cells, with open circuit voltages as high as 1.5 V. Despite their impressive performance, more efforts are required to develop industrially scalable perovskite solar cells from less toxic solvents. Towards that aim, this study presents the use of colloidal nanoparticle inks for room temperature fabrication of CsPbBr3 solar cells.", "author_names": [ "Quinten A Akkerman", "Marina Gandini", "Francesco Di Stasio", "Prachi Rastogi", "Francisco Palazon", "Giovanni Bertoni", "James M Ball", "Mirko Prato", "Annamaria Petrozza", "Liberato Manna" ], "corpus_id": 136250330, "doc_id": "136250330", "n_citations": 331, "n_key_citations": 0, "score": 1, "title": "Strongly emissive perovskite nanocrystal inks for high voltage solar cells", "venue": "", "year": 2017 }, { "abstract": "The morphology of hybrid perovskite thin films depends strongly on the processing parameters due to its complex crystallization kinetics from a solution to solid perovskite halide phase. It is also profoundly sensitive to the device area of the deposited thin film, and hence reproducible photoconversion efficiency (PCE) remained a bottleneck for the fabrication of efficient photovoltaic devices having large active area. The present work focuses on the investigations of the relationship between perovskite ink concentration dependent quality of the perovskite overlayer and PCE of the perovskite solar cells (PSC) while scaling up process. The field emission scanning electron microscopy images revealed that the surface coverage of perovskite overlayer depends on the concentration of perovskite solution and device area. The active area dependent current density (J) voltage (V) and external quantum efficiency measurements identify morphology dependent variation in charge transport/recombination pathways. We confirmed that among different precursor concentrations, 40 wt% perovskite ink is suitable to produce uniform perovskite overlayer over 1 cm2. As a result, highly reproducible PCE 13% has been achieved for the PSC having an active area of 1 cm2. Overall, our findings significantly provide new insights into the active area dependent PCE of PSC.", "author_names": [ "Arif D Sheikh", "Akhilesh P Patil", "Sawanta S Mali", "Chang Kook Hong", "Pramod S Patil" ], "corpus_id": 155166892, "doc_id": "155166892", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "New insights into active area dependent performance of hybrid perovskite solar cells", "venue": "Journal of Materials Science", "year": 2019 }, { "abstract": "Author(s) Sarang, Som Advisor(s) Ghosh, Sayantani Abstract: In just over a decade, perovskite semiconductors have shown immense promise as candidates for next generation opto electronic technologies, attributed to broad absorption spectra, long recombination lifetimes, ambipolar charge carrier conductivity and impressive electron mobility. Perovskite photovoltaics(PV) with power conversion efficiencies g 23% is challenging existing solar cell technologies and have revolutionized the field of solution processed solar cells. However, several drawbacks arising from perovskite stability and scalability have prevented them from achieving their full potential. The scope of this dissertation is to address some of these concerns, while also shedding light into the atypical physical properties of Perovskite semiconductors. The first part of the thesis deals with developing a rapid thoroughput and scalable fabrication route for perovskite thin film solar cells, utilizing an electro hydrodynamic spraying route inspired from 'Marangoni flow' seen in nature. The fabricated perovskite solar cells had superior current voltage characteristics and displayed an efficiency of g 16% which at the time (2015) was one of the highest reported power conversion efficiencies. Additionally, the developed fabrication method requires lower amounts of precursor solvents compared to other scalable approaches, thus reducing Lead wastage and mitigating environmental issues often associated with perovskite solar cells. Following this project, a range of low temperature, ultrafast optical spectroscopy techniques were used to probe the partial phase transitions in Perovskite thin films. This revealed charge migration pathways in perovskite thin films at low temperatures that prove detrimental for their device performance. In parallel, our experiments showed that the phase transition is associated with a crossover from excitonic to free charge carrier recombination in perovskite thin films.The above results encouraged us to investigate nanocrystals of perovskite semiconductors, aiming to achieve better crystal phase stability at low temperatures. We successfully quenched partial crystal phase transitions at low temperatures in perovskite quantum dots utilizing ligand based surface modification techniques. These findings highlighted aspects of perovskite phase stability linked to nanoscale morphology, paving way for improved perovskite devices operating at low temperatures.Lastly, the potential of perovskite quantum dots in spintronics applications were explored. We demonstrated optical spin polarization in perovskite quantum dots and measured their spin lifetimes using Hanle effect. In addition, Manganese ion dopants in Ruddlesden Popper perovskite quantum dots exhibited polarized photoluminescence emission attributed to strong exchange interactions In conclusion, we successfully developed high performing perovskite PV devices and demonstrated their plausible application in other opto electronic technologies, while also shedding light into its interesting physical properties.", "author_names": [ "Som Sarang" ], "corpus_id": 203530546, "doc_id": "203530546", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Perovskite semiconductors: From high performance devices to optical characterization", "venue": "", "year": 2019 }, { "abstract": "The slowdown of carrier cooling in lead halide perovskites (LHP) may allow the realization of efficient hot carrier solar cells. Much of the current effort focuses on the understanding of the mechanisms that retard the carrier relaxation, while proof of principle demonstrations of hot carrier harvesting have started to emerge. Less attention has been placed on the impact that the energy and momentum relaxation slowdown imparts on the spontaneous and stimulated light emission process. LHP nanocrystals (NCs) provide an ideal testing ground for such studies as they exhibit bright emission and high optical gain, while the carrier cooling bottleneck is further pronounced compared to their bulk analogues due to confinement. Herein, the luminescent properties of CsPbBr3, FAPbBr3, and FAPbI3 NCs in the strong photoexcitation regime are investigated. In the former two NC systems, amplified spontaneous emission is found to dominate over the radiative recombination at average carrier occupancy per nanocrystal larger than 5 10. On the other hand, under the same photoexcitation conditions in the FAPbI3 NCs, a longer lived population of hot carriers results in a competition between hot luminescence, stimulated emission, and defect recombination. The dynamic interplay between the aforementioned three emissive channels appears to be influenced by various experimental and material parameters that include temperature, material purity, film morphology, and excitation pulse width and wavelength.", "author_names": [ "Paris Papagiorgis", "Andreas Manoli", "Sozos Michael", "Caterina Bernasconi", "Maryna I Bodnarchuk", "Maksym V Kovalenko", "Andreas Othonos", "Grigorios Itskos" ], "corpus_id": 149444436, "doc_id": "149444436", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Unraveling the Radiative Pathways of Hot Carriers upon Intense Photoexcitation of Lead Halide Perovskite Nanocrystals.", "venue": "ACS nano", "year": 2019 }, { "abstract": "Abstract Organolead halide perovskite with excellent optoelectronic properties, which endows its potential applications in versatile optoelectronic device including solar cells and photodetectors. In spite of great efforts made on the perovskite photodetectors, novel device configurations based on perovskite films have to be explored to further improve the performance. Here, we present perovskite photodetectors enabled by a novel metal (Al) oxide semiconductor (perovskite) (MOS) structure. The unique photodetector can work on a wide voltage range and exhibits extreme characteristics with a pA scale dark current, and a high detectivity >1014 Jones) Both ultralow dark and light currents enable the small power consumption output ~nW under 2 mW cm 2 at 2 V. The C V data analysis proves that the charge carriers are accumulated at the oxide/perovskite interface, which leads to the reduction of the conduct band offset. At a low voltage the current transport behaviors for the MOS structure photodetectors are dominated by the Ohm's Law, while at a high voltage, the main mechanism is Schottky emission which is demonstrated by temperature dependence I V measurements. Our results strongly propose the use of perovskite based photodetectors with a unique MOS structure in the application of optoelectronic devices.", "author_names": [ "Yuming Zhang", "Kai Sun", "Ziyang Hu", "Yuejin Zhu", "Renxu Jia" ], "corpus_id": 126417765, "doc_id": "126417765", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Organolead halide perovskite based metal oxide semiconductor structure photodetectors achieving ultrahigh detectivity", "venue": "Solar Energy", "year": 2019 }, { "abstract": "We present a cation exchange approach for tunable A site alloys of cesium (Cs+ and formamidinium (FA+ lead triiodide perovskite nanocrystals that enables the formation of compositions spanning the complete range of Cs1 xFA xPbI3, unlike thin film alloys or the direct synthesis of alloyed perovskite nanocrystals. These materials show bright and finely tunable emission in the red and near infrared range between 650 and 800 nm. The activation energy for the miscibility between Cs+ and FA+ is measured ~0.65 eV) and is shown to be higher than reported for X site exchange in lead halide perovskites. We use these alloyed colloidal perovskite quantum dots to fabricate photovoltaic devices. In addition to the expanded compositional range for Cs1 xFA xPbI3 materials, the quantum dot solar cells exhibit high open circuit voltage VOC) with a lower loss than the thin film perovskite devices of similar compositions.", "author_names": [ "Abhijit Hazarika", "Qian Zhao", "E Ashley Gaulding", "Jeffrey A Christians", "Benjia Dou", "Ashley R Marshall", "Taylor Moot", "Joseph J Berry", "Justin C Johnson", "Joseph M Luther" ], "corpus_id": 52813134, "doc_id": "52813134", "n_citations": 75, "n_key_citations": 0, "score": 0, "title": "Perovskite Quantum Dot Photovoltaic Materials beyond the Reach of Thin Films: Full Range Tuning of A Site Cation Composition.", "venue": "ACS nano", "year": 2018 }, { "abstract": "Metal halide perovskites (MHPs) are of great interest for optoelectronics because of their high quantum efficiency in solar cells and light emitting devices. However, exploring an effective strategy to further improve their optical activities remains a considerable challenge. Here, we report that nanocrystals (NCs) of the initially nonfluorescent zero dimensional (0D) cesium lead halide perovskite Cs4PbBr6 exhibit a distinct emission under a high pressure of 3.01 GPa. Subsequently, the emission intensity of Cs4PbBr6 NCs experiences a significant increase upon further compression. Joint experimental and theoretical analyses indicate that such pressure induced emission (PIE) may be ascribed to the enhanced optical activity and the increased binding energy of self trapped excitons upon compression. This phenomenon is a result of the large distortion of [PbBr6]4 octahedral motifs resulting from a structural phase transition. Our findings demonstrate that high pressure can be a robust tool to boost the photoluminescence efficiency and provide insights into the relationship between the structure and optical properties of 0D MHPs under extreme conditions.The potential optoelectronic applications of metal halide perovskites make exploration and tuning of their optical properties of great interest. Here the authors show that non emitting zero dimensional cesium lead halide perovskites become strongly fluorescent under high pressure, due to distortion induced effects.", "author_names": [ "Zhiwei Ma", "Zhun Liu", "Siyu Lu", "Lei Wang", "Xiaolei Feng", "Dongwen Yang", "Kai Wang", "Guanjun Xiao", "Lijun Zhang", "Simon A T Redfern", "Bo Zou" ], "corpus_id": 53092100, "doc_id": "53092100", "n_citations": 96, "n_key_citations": 1, "score": 0, "title": "Pressure induced emission of cesium lead halide perovskite nanocrystals", "venue": "Nature Communications", "year": 2018 }, { "abstract": "Perovskite nanocrystals have shown themselves to be useful for both absorption and emission based applications, including solar cells, photodetectors, and LEDs. Here we present a new class of size composition and shape tunable nanocrystals made from Tl3PbX5 (X= Cl, Br, I) These can be synthesized via colloidal methods to produce faceted spheroidal nanocrystals, and perovskite TlPbI3 nanowires. Crystal structures for the orthorhombic and tetragonal phase materials, for both pure and mixed halide species, are compared to the literature and also calculated from first principles in VASP. We show the ability to tune the band gap by halide substitution to create materials that can absorb strongly between 250 and 450 nm. In addition, we show evidence of the confinement effect in pure halide Tl3PbBr5 nanocrystals suggesting size tuning is possible as well. By tuning the band gap we can create materials with specific absorption spectra suitable for photodetection that display conduction and photoresponse pro.", "author_names": [ "Parth Vashishtha", "Dani Z Metin", "Matthew E Cryer", "Kai Chen", "Justin M Hodgkiss", "Nicola Gaston", "Jonathan E Halpert" ], "corpus_id": 103411545, "doc_id": "103411545", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Shape Size and Composition Controlled Thallium Lead Halide Perovskite Nanowires and Nanocrystals with Tunable Band Gaps", "venue": "", "year": 2018 }, { "abstract": "Colloidal semiconductor nanocrystals (NCs) also known as colloidal quantum dots (QDs) have played an indispensable role in the development of modern nanoscience and nanotechnology because of their unique optical and electronic properties, and they are still being intensively investigated for various potential applications. Semiconductor NCs offer significant advantages over conventional organic fluorescent dyes, including the tunability of emission color by their size and composition, excellent color purity, ease of preparation and controllable surface chemistry enabling their dispersion in various solvents for solution processability. As a consequence, the past two decades have witnessed tremendous progress in the shape controlled synthesis, self assembly, surface functionalization and optoelectronic device applications of II VI and III V semiconductor QDs. Recently, metal halide perovskites have emerged as a new class of semiconductor material with extraordinary optical and electronic properties. Perovskite materials of the form APbX3 (with A as the inorganic or organic cation, and X Cl, Br, or I) have been well known since the late 1970s from the work by Weber. They became popular after the first report on halide perovskite solar cells in 2009 by Kojima et al. Since then, halide perovskites have created large excitement in the photovoltaic research community that was stimulated by a meteoric rise in the power conversion efficiency of perovskite solar cells from 3.8% to over 22% in a short development time. In addition, the outstanding optical properties of perovskites have made them excellent light sources for applications in LEDs, photodetectors, photo transistors and lasers. The early studies on perovskites were focused on the optimization of bulk films for device applications. Despite the rapid progress in perovskite materials in photovoltaics and optoelectronics, the properties that make them so special, like their tolerance to defects, are yet to be fully understood. From the II VI and III V semiconductor materials, we know that colloidal nanocrystals offer several advantages over their bulk counterparts, including solution processability, enhanced photoluminescence efficiency and tunable emission through quantum confinement effects. The first solution phase colloidal synthesis of organic inorganic hybrid perovskite NCs was published in 2014 by Perez Prieto et al. A year later, Kovalenko et al. reported the colloidal synthesis of all inorganic perovskite NCs. Since then, metal halide perovskite NCs have received significant research interest due to their extraordinary optical properties as well as their appeal as emitters in efficient light sources. The unique feature of perovskite NCs is that they exhibit near unity photoluminescence quantum yield (PLQY) without the need of a core shell architecture, unlike the conventional QDs (e.g. CdSe/CdS/ZnS and CdSe/ZnSe/ZnS core multi shell NCs) The emission color of perovskite NCs is easily tunable across the visible spectrum by the halide composition and by confinement effects. Like in conventional colloidal systems, ligands play a crucial role in the shape and size control of perovskite NCs, and also in the passivation of surface defects, which is decisive for high PLQY. In the last few years, we have witnessed extremely rapid progress in the synthesis of perovskite NCs of a wide range of morphologies and shapes, such as quantum dots, nanocubes, nanowires, nanorods, nanoplatelets, and nanosheets. In fact, it is possible to control the dimensions of NCs with monolayer precision, which leads to strong tunability of the band gap in nanowires, nanoplatelets and nanosheets. Introducing organic molecules as spacer layers in between the octahedral planes enabled the fabrication of layered perovskites with a large band gap and emission at a wavelength of around 400 nm, which can be tuned Chair for Photonics and Optoelectronics, NanoInstitute Munich, Department of Physics, LudwigMaximilians Universitat (LMU) Koniginstr. 10, 80539 Munich, Germany. E mail: l.polavarapu@lmu.de Institute of Functional Nano and Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon Based Functional Materials and Devices, Soochow University, China. E mail: qiaozhang@suda.edu.cn Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy. E mail: Roman.Krahne@iit.it", "author_names": [ "Lakshminarayana Polavarapu", "Qiao Zhang", "Roman Krahne" ], "corpus_id": 206145651, "doc_id": "206145651", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Nanoscale Nanoscale Advances joint themed collection on halide perovskite nanocrystals.", "venue": "Nanoscale", "year": 2019 }, { "abstract": "A rational design and construction of white light emitting components based on semiconductor materials are extremely important in lighting and display technologies.[1 4] In general, there are two reasonable approaches developed to realize the white light source. They are the synthesis of semiconductor alloy nanostructures with widely tunable band gaps,[5 7] and the construction of a white lighting emitter with various single band gap semiconductors that have monochromatic luminescence with high quantum efficiency.[8 10] However, white light generated from red green blue emitters based on semiconductor nanostructures has been known as the major challenge in the solid state lighting community.[1,2,8,9] For example, a suitable mix for white light radiation with favorable wavelengths and intensity ratios, proper color rendering index, and high stability is still lacking.[11,12] Recently, perovskite materials have brought a variety of new opportunities for the advancement of nanophotonics and optoelectronics.[13 23] In particular, inorganic metal halide perovskites, such as cesium lead halide perovskites, have drawn enormous attention because they show great promises for various photoelectric applications, such as the natural highquality whispering gallery mode (WGM) or Fabry Perot (F P) resonators,[16,17,24 26] laser cooling,[18] solar cells,[27 30] and light emitting diodes.[31 33] Moreover, they also exhibit a broad band gap tunability for multifunctional devices and circuits covering the entire visible spectrum.[19,20] Therefore, these unusual semiconductor materials may offer the opportunity to design novel white light emitting devices in future full color displays. Currently, solution based synthesis methods have been commonly used to realize the band gap tunable cesium lead halide perovskite (CsPbX3, X Cl, Br, I) quantum dots.[34 37] Protesescu et al. reported a new avenue for the growth of CsPbX3 perovskite nanocrystals by the solution phase method, which shows bright emissions with a wide color gamut.[38] In comparison, chemical vapor deposition (CVD) is another attractive approach for the synthesis of diverse Wavelength tunable nano/microlasers are essential components for various highly integrated and multifunctional photonic devices. Based on the different band gap/composition of inorganic cesium lead halide perovskite materials, broad band light absorption and emission devices can be achieved. Herein, a vapor liquid solid route for growing cesium lead halide perovskite (CsPbX3, X Cl, Br, I) microcrystal structures is demonstrated. These square shaped microstructures exhibit strong blue, green, and red photoluminescence, indicating that their band gaps can be engineered to cover the entire visible range. Optically pumped red green blue whispering gallery mode lasers based on the controlled composition of these microcrystals are successfully realized at room temperature. Moreover, rationally designed white light emitting chips with high brightness are fabricated utilizing these metal halide perovskite microstructures grown on sapphire. All these results evidently suggest a feasible route to the design of red green blue lasers and white light emitters for potential applications in full color displays as well as photonic devices. Perovskite Microlasers", "author_names": [ "Pengfei Guo", "Mohammad Kamal Hossain", "Xia Shen", "Haibin Sun", "Wenchao Yang", "Chao Liu", "Chun Yuen Ho", "Cheuk Kai Gary Kwok", "Sai-Wing Tsang", "Yongsong Luo", "Johnny C Ho", "Kin Man Yu" ], "corpus_id": 103427944, "doc_id": "103427944", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Room Temperature Red Green Blue Whispering Gallery Mode Lasing and White Light Emission from Cesium Lead Halide Perovskite (CsPbX3, X Cl, Br, I) Microstructures", "venue": "", "year": 2018 } ]

[ { "abstract": "Electro optic modulators translate high speed electronic signals into the optical domain and are critical components in modern telecommunication networks1,2 and microwave photonic systems3,4. They are also expected to be building blocks for emerging applications such as quantum photonics5,6 and non reciprocal optics7,8. All of these applications require chip scale electro optic modulators that operate at voltages compatible with complementary metal oxide semiconductor (CMOS) technology, have ultra high electro optic bandwidths and feature very low optical losses. Integrated modulator platforms based on materials such as silicon, indium phosphide or polymers have not yet been able to meet these requirements simultaneously because of the intrinsic limitations of the materials used. On the other hand, lithium niobate electro optic modulators, the workhorse of the optoelectronic industry for decades9, have been challenging to integrate on chip because of difficulties in microstructuring lithium niobate. The current generation of lithium niobate modulators are bulky, expensive, limited in bandwidth and require high drive voltages, and thus are unable to reach the full potential of the material. Here we overcome these limitations and demonstrate monolithically integrated lithium niobate electro optic modulators that feature a CMOS compatible drive voltage, support data rates up to 210 gigabits per second and show an on chip optical loss of less than 0.5 decibels. We achieve this by engineering the microwave and photonic circuits to achieve high electro optical efficiencies, ultra low optical losses and group velocity matching simultaneously. Our scalable modulator devices could provide cost effective, low power and ultra high speed solutions for next generation optical communication networks and microwave photonic systems. Furthermore, our approach could lead to large scale ultra low loss photonic circuits that are reconfigurable on a picosecond timescale, enabling a wide range of quantum and classical applications5,10,11 including feed forward photonic quantum computation.Chip scale lithium niobate electro optic modulators that rapidly convert electrical to optical signals and use CMOS compatible voltages could prove useful in optical communication networks, microwave photonic systems and photonic computation.", "author_names": [ "Cheng Wang", "Mian Zhang", "Xi Chen", "Maxime Bertrand", "Amirhassan Shams-Ansari", "Sethumadhavan Chandrasekhar", "Peter J Winzer", "Marko Loncar" ], "corpus_id": 52810911, "doc_id": "52810911", "n_citations": 619, "n_key_citations": 14, "score": 0, "title": "Integrated lithium niobate electro optic modulators operating at CMOS compatible voltages", "venue": "Nature", "year": 2018 }, { "abstract": "", "author_names": [ "Mian Zhang", "Cheng Wang", "Prashanta Kharel", "Di Zhu", "Marko Loncar" ], "corpus_id": 233707747, "doc_id": "233707747", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Integrated lithium niobate electro optic modulators: when performance meets scalability", "venue": "", "year": 2021 }, { "abstract": "Since the emergence of optical fiber communications, lithium niobate (LN) has been the material of choice for electro optic modulators, featuring high data bandwidth and excellent signal fidelity. Conventional LN modulators however are bulky, expensive and power hungry, and cannot meet the growing demand in modern optical data links. Chip scale, highly integrated, LN modulators could offer solutions to this problem, yet the fabrication of low loss devices in LN thin films has been challenging. Here we overcome this hurdle and demonstrate monolithically integrated LN electro optic modulators that are significantly smaller and more efficient than traditional bulk LN devices, while preserving LN's excellent material properties. Our compact LN electro optic platform consists of low loss nanoscale LN waveguides, micro ring resonators and miniaturized Mach Zehnder interferometers, fabricated by directly shaping LN thin films into sub wavelength structures. The efficient confinement of both optical and microwave fields at the nanoscale dramatically improves the device performances featuring a half wave electro optic modulation efficiency of 1.8 Vcm while operating at data rates up to 40 Gbps. Our monolithic LN nanophotonic platform enables dense integration of high performance active components, opening new avenues for future high speed, low power and cost effective communication networks.", "author_names": [ "Cheng Wang", "Mian Zhang", "Brian Stern", "Michal Lipson", "Marko Loncar" ], "corpus_id": 26152301, "doc_id": "26152301", "n_citations": 266, "n_key_citations": 6, "score": 0, "title": "Nanophotonic lithium niobate electro optic modulators.", "venue": "Optics express", "year": 2018 }, { "abstract": "Both long haul and short distance network interconnects for conventional data networks and intra /interchip data links continue to scale in complexity and bandwidth. This has signalled the emergence of the optical interconnect, with silicon photonics being the leading candidate due to its unique combination of low fabrication costs and performance enhancements. Electronic photonic integration compatibility with CMOS technology, makes integrated photonic circuits more appealing. Hence, it is very critical to make the fabrication of integrated photonic devices as foundry compatible as possible to fully utilize CMOS foundry capabilities. We have proposed a fabrication method for thin film lithium niobate (LN) based electro optic modulators which has excellent compatibility with silicon photonic foundry processes and minimizes the back end of the line processes. This paves the way for large scale production of the hybrid Silicon lithium niobate devices.", "author_names": [ "Reza Safian", "Swapnajit Chakravarty", "Min Teng", "Leimeng Zhuang" ], "corpus_id": 213901099, "doc_id": "213901099", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Foundry compatible thin film lithium niobate electro optic modulators", "venue": "OPTO", "year": 2020 }, { "abstract": "Abstract Integrated optics is poised to revolutionize several data communication applications. The development of high performance electro optic modulators is essential for the technology to be viable. In this paper, single mode electro optic modulators in x cut lithium niobate thin film are designed, simulated, and analyzed. The single mode conditions of lithium niobate ridge waveguides are analyzed in detail. The design parameters of Y branch and separation distances between electrodes and ridge waveguides are optimized. The half wave voltage of the electro optic modulator with device lengths of 10 mm is determined. The half wave voltage length product is about 2.2 V*cm indicating the efficient electric optical modulation. This study is helpful for understand of electro optic modulator structures in lithium niobate thin film, as well as for the fabrication of high performance and multifunctional electro optic modulation devices.", "author_names": [ "Huangpu Han", "Bingxi Xiang" ], "corpus_id": 216327919, "doc_id": "216327919", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Integrated electro optic modulators in x cut lithium niobate thin film", "venue": "", "year": 2020 }, { "abstract": "In this study, we designed, simulated, and optimized proton exchanged integrated Mach Zehnder modulators in a 0.5 mm thick x cut lithium niobate thin film. The single mode conditions, the mode distributions, and the optical power distribution of the lithium niobate channel waveguides are discussed and compared in this study. The design parameters of the Y branch and the separation distances between the electrodes were optimized. The relationship between the half wave voltage length production of the electro optic modulators and the thickness of the proton exchanged region was studied.", "author_names": [ "Huangpu Han", "Bingxi Xiang", "Tao Lin", "Guangyu Chai", "Shuangchen Ruan" ], "corpus_id": 209350853, "doc_id": "209350853", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Design and Optimization of Proton Exchanged Integrated Electro Optic Modulators in X Cut Lithium Niobate Thin Film", "venue": "Crystals", "year": 2019 }, { "abstract": "Author(s) Weigel, Peter Orlando Advisor(s) Mookherjea, Shayan Abstract: Electro optic modulators (EOMs) serve as a technological pillar of the modern telecommunications industry. Without these devices, which convert electrical data into optical data through one of several physical phenomena (depending on the specific technology) telecommunications channels would be severely bandwidth limited, particularly within data centers. To meet the ever increasing bandwidth demands of the industry, either more EOMs are necessary (resulting in higher power requirements) or higher bandwidth EOM technology must be developed. This thesis discusses the theory, design, fabrication, and characterization of foundry compatible hybrid silicon lithium niobate (Si LN) electro optic modulators integrated on a wafer platform, a new technology with potentially far reaching applications.By bonding a thin film of ion sliced LN crystal, which retains the crystal properties of bulk LN, to silicon waveguides in the Mach Zehnder modulator configuration, it is theoretically possible to exceed the bandwidth limitations of all Si modulators without abandoning the scalable, dense silicon on insulator (SOI) platform. These hybrid devices make use of the favorable linear electro optic Pockels effect of LN while using the high index Si waveguide to reduce the optical mode area, so that low voltage, high bandwidth devices can be realized. This thesis focuses on developing broadband EOMs with cutoff frequencies beyond 100 GHz. Developing this technology on an SOI wafer platform fabricated via photolithography in a foundry facility presents a realistic path towards next generation high speed, low power integrated EOMs.", "author_names": [ "Peter O Weigel" ], "corpus_id": 117491738, "doc_id": "117491738", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High Speed Hybrid Silicon Lithium Niobate Electro Optic Modulators Related Technologies", "venue": "", "year": 2018 }, { "abstract": "Silicon photonics is a platform that enables densely integrated photonic components and systems and integration with electronic circuits. Depletion mode modulators designed on this platform suffer from a fundamental frequency response limit due to the mobility of carriers in silicon. Lithium niobate based modulators have demonstrated high performance, but the material is difficult to process and cannot be easily integrated with other photonic components and electronics. In this manuscript, we simultaneously take advantage of the benefits of silicon photonics and the Pockels effect in lithium niobate by heterogeneously integrating silicon photonic integrated circuits with thin film lithium niobate samples. We demonstrate the most CMOS compatible thin film lithium niobate modulator to date, which has electro optic 3 dB bandwidths of 30.6 GHz and half wave voltages of 6.7 Vxcm. These modulators are fabricated entirely in CMOS facilities, with the exception of the bonding of a thin film lithium niobate sample post fabrication, and require no etching of lithium niobate.", "author_names": [ "Nicholas Boynton", "Hong Cai", "Michael Gehl", "Shawn Arterburn", "Christina M Dallo", "Andrew Pomerene", "Andrew L Starbuck", "Dana Hood", "Douglas C Trotter", "Thomas Aquinas Friedmann", "Christopher T DeRose", "Anthony L Lentine" ], "corpus_id": 211833271, "doc_id": "211833271", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "A heterogeneously integrated silicon photonic/lithium niobate travelling wave electro optic modulator.", "venue": "Optics express", "year": 2020 }, { "abstract": "The processes of the excitation of acoustic vibrations and their influence on the optical signals in integrated electro optic modulators on substrates of lithium niobate have been investigated. The resonant frequencies of the excitation of substrate vibrational modes have been determined. It has been shown that acoustic vibrations can make a significant contribution to the modulator transfer characteristic at frequencies up to several hundred megahertz, which should be taken into account when using the modulators at low frequencies, for example, as a part of fiber optic sensors.", "author_names": [ "Andrey V Varlamov", "Mikhail Yu Plotnikov", "Artem Aleinik", "Piotr M Agrusov", "I Il'ichev", "Alexander V Shamray", "Aleksandr A Vlasov" ], "corpus_id": 125160151, "doc_id": "125160151", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Acoustic vibrations in integrated electro optic modulators on substrates of lithium niobate", "venue": "", "year": 2017 }, { "abstract": "We demonstrate a Bragg modulator integrated on a lithium niobate on insulator platform with a footprint of 10x500 mm2 that operates at 56 Gbit/s. This electro optic Bragg reflector has a DC tuning efficiency of 23.37+ 0.55 pm/V.", "author_names": [ "Marc Reig Escale", "David Pohl", "Wolfgang Heni", "Benedikt Baeuerle", "Arne Josten", "Anton Sergeyev", "Juerg Leuthold", "Rachel Grange" ], "corpus_id": 139749437, "doc_id": "139749437", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Integrated Electro optic Bragg Modulators in Lithium Niobate Nanowaveguides", "venue": "", "year": 2018 } ]