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New Submicron Low Gate Leakage In_0.52Al_0.48As-In_0.7Ga_0.3As pHEMT for Low-Noise Applications

MICROMACHINES 2021年第12期12卷 1497-1497页

作者： Mohamed, Mohamed Fauzi Packeer Omar, Mohamad Faiz Mohamed Khan, Muhammad Firdaus Akbar Jalaludin Ghazali, Nor Azlin Hairi, Mohd Hendra Falina, Shaili Baharin, Mohd Syamsul Nasyriq Samsol Univ Sains Malaysia Sch Elect & Elect Engn Nibong Tebal 14300 Pulau Pinang Malaysia Univ Sains Malaysia Collaborat Microelect Design Excellence Ctr CEDEC Sains USM Bayan Lepas 11900 Pulau Pinang Malaysia Tech Univ Malaysia Malacca Fac Elect Engn Durian Tunggal 76100 Melaka Malaysia Waseda Univ Fac Sci & Engn Tokyo 1698555 Japan Univ Sains Malaysia Inst Nano Optoelect Res & Technol INOR Sains USM Bayan Lepas 11900 Pulau Pinang Malaysia

Conventional pseudomorphic high electron mobility transistor (pHEMTs) with lattice-matched InGaAs/InAlAs/InP structures exhibit high mobility and saturation velocity and are hence attractive for the fabrication of three-terminal low-noise and high-frequency devices, which operate at room temperature. The major drawbacks of conventional pHEMT devices are the very low breakdown voltage (< 2 V) and the very high gate leakage current (& SIM;1 mA/mm), which degrade device and performance especially in monolithic microwave integrated circuits low-noise amplifiers (MMIC LNAs). These drawbacks are caused by the impact ionization in the low band gap, i.e., the InxGa((1-x))As (x = 0.53 or 0.7) channel material plus the contribution of other parts of the epitaxial structure. The capability to achieve higher frequency operation is also hindered in conventional InGaAs/InAlAs/InP pHEMTs, due to the standard 1 mu m flat gate length technology used. A key challenge in solving these issues is the optimization of the InGaAs/InAlAs epilayer structure through band gap engineering. A related challenge is the fabrication of submicron gate length devices using I-line optical lithography, which is more cost-effective, compared to the use of e-Beam lithography. The main goal for this research involves a radical departure from the conventional InGaAs/InAlAs/InP pHEMT structures by designing new and advanced epilayer structures, which significantly improves the performance of conventional low-noise pHEMT devices and at the same time preserves the radio frequency (RF) characteristics. The optimization of the submicron T-gate length process is performed by introducing a new technique to further scale down the bottom gate opening. The outstanding achievements of the new design approach are 90% less gate current leakage and 70% improvement in breakdown voltage, compared with the conventional design. Furthermore, the submicron T-gate length process also shows an increase of about 58% and 33% in f(

关键词： 2DEG iii-V material InAlAs InGaAs InP LNA low temperature (LT) MBE MMIC pHEMT semiconductor device

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A Computational Camera with Programmable Optics for Snapshot High-Resolution Multispectral Imaging 14th

A Computational Camera with Programmable Optics for Snapshot...

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14th Asian Conference on Computer Vision (ACCV)

作者： Chen, Jieen Hirsch, Michael Eberhardt, Bernhard Lensch, Hendrik P. A. Eberhard Karls Univ Tuebingen Tubingen Germany Amazon Res Tubingen Germany Stuttgart Media Univ Stuttgart Germany

ISBN: (纸本)9783030208936;9783030208929

Spectral imaging has many uses in the field of conservation of cultural heritage, medical imaging, etc. It collects spectral information at each location of an image plane as an image cube. Among various approaches, snapshot multispectral imaging techniques measure the cube within one integration period. Previous work has addressed the issue of optical design, while recent developments have shifted the focus towards computation. In this paper, we present a snapshot multispectral imaging technique with a computational camera and a corresponding image restoration algorithm. The main characteristics are: (1) transferring spectral information to the spatial domain by engineering user-defined PSFs;(2) measuring spectral images by computationally inverting the image formation. The design of our computational camera is based on a phase-coded aperture technique to generate spatial and spectral variant PSFs. The corresponding algorithm is designed by adapting single-channel and cross-channel priors. We show experimentally the viability of our technique: it reconstructs high resolution multispectral images from a snapshot. We further validate that the role of PSF design is critical.

关键词： optical design

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丝素蛋白纤维及功能化材料的设计与构筑

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高分子学报 2021年第1期52卷 29-46,I0003,I0001页

作者：范苏娜陈杰顾张弘姚响张耀鹏东华大学纤维材料改性国家重点实验室材料科学与工程学院上海201620

随着环境污染、资源枯竭和医疗健康等问题的加剧,研发同时满足特定使用性能、安全性及可再生性的新型材料成为当前的发展趋势.而丝素蛋白材料正是以天然蚕丝为基本原材料,经一定的加工和功能化而形成的具有特殊结构、独特性能和广泛应... 详细信息

随着环境污染、资源枯竭和医疗健康等问题的加剧,研发同时满足特定使用性能、安全性及可再生性的新型材料成为当前的发展趋势.而丝素蛋白材料正是以天然蚕丝为基本原材料,经一定的加工和功能化而形成的具有特殊结构、独特性能和广泛应用的生物质材料,近年来在生物医药、生物电子、智能传感等领域展现出巨大的应用潜力.本专论总结了丝素蛋白纤维及功能化材料的最新成果,结合本课题组相关工作,重点阐述了再生丝素蛋白纤维的仿生制备、生物医用支架的构筑与功能化、智能电子材料的设计以及天然多功能蚕丝及其构筑基元制备的研究进展,以期为高性能丝素蛋白材料的设计与构筑提供指导和借鉴.

关键词：丝素蛋白多级结构功能材料仿生构筑

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Proceedings of SPIE - The International Society for optical engineering

Proceedings of SPIE - The International Society for Optical ...

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Physics, Simulation, and Photonic engineering of Photovoltaic Devices Viii 2019

ISBN: (纸本)9781510624689

The proceedings contain 28 papers. The topics discussed include: simulation of photon transport in resonant double-diode structures;light absorption enhancement in ultra-thin layers for hot-carrier solar cells: first developments towards the experimental demonstration of an enhanced hot-carrier effect with light trapping;slowed hot carrier cooling in multiple quantum wells for application to hot carrier solar cells;unusual hot carrier effect and improved carrier extraction observed in asymmetric dilute-nitride quantum-engineered solar cells through photoluminescence (PL) and external quantum efficiency (EQE) measurements;efficient multiphysics modeling of thin-film solar cells with periodically textured surfaces;tunable prism based upon novel piezoelectric nanoparticle/sol-gel design used for active solar cells concentrators;optimized solar cells based on changes in resonance structure as a function of the refractive index and the thickness;and a porous Ge/Si interface layer for defect-free iii-V multi-junction solar cells on silicon.

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Comparison of the Efficacy of Three Direct Ophthalmoscopes: A Clinical Study 20

Comparison of the Efficacy of Three Direct Ophthalmoscopes: ...

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Conference on current developments in Lens design and optical engineering XX

作者： Parthasarathy, Mohana Kuppuswamy Faruq, Ibrahim Arthurs, Eugene Lakshminarayanan, Vasudevan Univ Waterloo Sch Optometry & Vis Sci Theoret & Expt Epistemol Lab Waterloo ON Canada Costco Opt Waterloo ON Canada SPIE Bellingham WA USA Univ Waterloo Dept Phys Waterloo ON Canada Univ Waterloo Dept ECE Waterloo ON Canada Univ Waterloo Dept Syst Design Engn Waterloo ON Canada

ISBN: (数字)9781510629028

ISBN: (纸本)9781510629028

Retinal examination using direct ophthalmoscope is preferred over other techniques for screening purposes because of its portability and high magnification, despite its power sustainability and cost issues. With increasing number of low-cost sustainable devices available in the market, it is important to assess the efficacy of the devices. We compared three devices - Arclight ophthalmoscope, a D-Eye attached to iPhone 6, and conventional ophthalmoscope Heine K180 - in terms of ease of examination, usage, field of view, color rendition, patient comfort, length of examination, and closeness to the eye. Two trained optometrists examined 26 undilated eyes and graded the ease of retinal examination, ease of use and assessed vertical cup:disc ratio (VCDR). Patients reported their comfort level in terms of glare produced by the light source, length of examination and closeness to the eye. The examiners had a good agreement for all assessments. Of 26 eyes, VCDR assessment was not possible in 10/ 26 (38.4%) of the examinations, in (3/26, 11.5%) examinations with Arclight, in 0/26 examinations with D-Eye. Ease of use score was higher for Arclight and D-Eye than Heine. D-Eye had a relatively larger field of view than other 2 devices. Heine ranked first in color rendition. The luminance level of the high-beam setting of Arclight was more than twice that of Heine and D-Eye. Despite that, the patients reported experiencing uncomfortable glare in Heine (14/26, 53.8%), significant glare with Arclight (16/26, 61.5%) and some/no glare with D-Eye. The examination time was shorter when using D-Eye. Overall, D-Eye scored better in most of the evaluation items followed by Arclight.

关键词： Direct Ophthalmoscope Retina cup to disc ratio D-Eye smartphone ophthalmoscope Arclight ophthalmoscope Heine ophthalmoscope solar powered ophthalmoscope

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optical-RF dual relay communication system for 1000-Au interstellar mission 70

Optical-RF dual relay communication system for 1000-Au inter...

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70th International Astronautical Congress, IAC 2019

作者： Kufahl, Katelyn M. Boone, Bradley G. Beck, Adam L. Space Exploration Sector Johns Hopkins University Applied Physics Laboratory 11100 Johns Hopkins Rd LaurelMD20755 United States Whiting School of Engineering Johns Hopkins University BaltimoreMD21218 United States

The goal of a realistic interstellar mission to the nearest star, recently announced by NASA as a new space exploration objective targeted for circa 2069, presents an exciting prospect for creating a pragmatic but visionary mission design. In light of such a long-term mission goal, potential technological developments that might be mission enablers are a matter of speculation at best, but the basic physical principles underlying telecommunications subsystem conceptual design are well within our grasp. For example, the range required of a communications link to the Alpha Centauri system is prohibitively large due to current and foreseeable engineering limits in pointing capability, receiver sensitivity, and power transmission in both RF and optical domains. However, realistic design specifications can be identified if the mission concept is broadened in two ways: launch a precursor mission to a distance of 1000 AU, and implement the precursor mission not as a single spacecraft but as a fleet of several spacecraft launched in periodic succession. In doing so, the communications subsystem can take the form of a relay chain for which the spacing is determined by the upper limits of downlink transmission capability at the time of launch. By reducing the required link range to within achievable limits, link analysis can be further constrained by examination of tradeoffs in transmitter output power, data rate, bit error rate, antenna sizes, pointing loss, path attenuation, turbulence effects, and link availability at both optical and radio frequencies. The proposed subsystem is dual-channel: an optical link to achieve the minimum required downlink data rates, and an RF link to minimize pointing loss for spacecraft emergency recovery. Through the implementation of a relay-based dual-channel design, the subsystem can yield effective and reliable downlink data transmission over communication distances of unprecedented vastness. Copyright © 2019 by the International Astronauti

关键词： optical communication

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current trends, challenges, and perspectives of anti-fogging technology: Surface and material design, fabrication strategies, and beyond

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PROGRESS IN MATERIALS SCIENCE 2019年 99卷 106-186页

作者： Duran, Ivan Rodriguez Laroche, Gaetan Univ Laval Dept Genie Mines Met & Mat Ctr Rech Mat Avances Lab Ingn Surface 1065 Ave Med Quebec City PQ G1V 0A6 Canada Hop St Francois Assise Ctr Hosp Univ Quebec Ctr Rech 10 Rue Espinay Quebec City PQ G1L 3L5 Canada

Transparent materials such as glasses and some polymers play an essential role in our daily life. Indeed, it is well known that their application in mirrors, windows, automobile windshields, and eyewear make our day-to-day activities more comfortable. These examples aside, many more can also be found in several spheres of human activity, including such sectors as diverse and distinct as the medical, photovoltaic and food industry fields. Unfortunately, due to the unavoidable condensation of water vapor on solid surfaces, these materials undergo fogging under normal operating conditions. More than a mere nuisance, this naturally occurring phenomenon adversely affects their optical performance as it lowers the light-transmitting capability and often gives rise to esthetical, hygienic, and safety concerns. In this context, research in the field of anti-fogging technology has attracted growing interest, particularly in recent years, for numerous potential applications. In this review, recent developments in the design and manufacturing of anti-fogging surfaces are described in detail, beginning with the fogging mechanism in terms of nucleation and growth of water drops. Anti-fogging strategies explored thus far and mainly focusing on hydrophilic and hydrophobic surfaces are then extensively described. Finally, based on current research in this promising field, future trends and prospects for their effective implementation are presented.

关键词： Fog resistant surfaces Theoretical aspects of fogging Water drops Light scattering Anti-fogging strategies

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optical designs of the objectives for special studies in polarizing microscope 19

Optical designs of the objectives for special studies in pol...

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19th Conference on current developments in Lens design and optical engineering

作者： Frolov, Dmitry N. Vinogradova, Olga A. Frolov, Alexey D. Tabachkov, Alexey G. Project Labor Microscopes Zapovednaya St 51A St Petersburg 194356 Russia

Presents the results of the optical design of lens objectives for polarization light microscopes, including to ensure that the special techniques. Sometimes such methods require the use of objectives similar magnifica... 详细信息

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

关键词： Microscopy Lens system design optical design and fabrication Objectives for microscopes Lens objectives system design Objectives for polarizing microscopes Polarizing microscopy

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optical design of CCF PlanApo microobjectives 50 mm observation and super long working distance 19

Optical design of CCF PlanApo microobjectives 50 mm observat...

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19th Conference on current developments in Lens design and optical engineering

作者： Frolov, Dmitry N. Vinogradova, Olga A. Frolov, Alexey D. Wen, Liyun Jing, Fanhua Project Labor Microscopes Zapovednaya St 51A St Petersburg 194356 Russia Kozo Opt Ltd 19E18 Zhenghong St Nanjing Jiangsu Peoples R China

The main difference is a significant expansion of the linear field, which reaches 50 mm in the image plane. However, in this case, a planapochromatic correction must be achieved for the usual visible spectral range. S... 详细信息

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

关键词： Lens system design optical design and fabrication Microscopy Objectives for microscopes

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optical design of LED Marine Beacons 19

Optical Design of LED Marine Beacons

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19th Conference on current developments in Lens design and optical engineering

作者： Lin, Shih-Kang Jen, Yung-Chang Lee, Xuan-Hao Yu, Yeh-Wei Yang, Tsung-Hsun Sun, Ching-Cherng Natl Cent Univ Dept Opt & Photon Chungli 32001 Taiwan Natl Cent Univ Opt Sci Ctr Taoyuan 32001 Taiwan

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

Two optical designs for marine beacon based on Direct In-line Package (DIP) LED is proposed and demonstrated. The luminous intensity of the marine beacon using DIP LED can achieve to the IALA recommendation's requirement of 5 nautical miles. The measurement of color coordinates can also fit the IALA recommendation's requirement. By the surface-structured TIR lens, we successfully keep the divergence angle to 68 degrees in the horizontal direction and converge to 8 degrees in the vertical direction.

关键词： DIP LED optical design marine beacons IALA

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