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有源区掺杂的AlGaN基深紫外激光二极管性能优化

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原子与分子物理学报 2024年第3期41卷 170-175页

作者：尹孟爽张傲翔张鹏飞贾李亚王芳刘俊杰刘玉怀郑州大学电气与信息工程学院电子材料与系统国际联合研究中心河南省电子材料与系统国际联合实验室郑州450001 郑州大学智能传感研究院郑州450001 郑州大学产业技术研究院有限公司郑州450001 郑州唯独电子科技有限公司郑州450001

为了改善深紫外激光二极管的性能,本文提出了有源区量子势垒n掺杂、p掺杂和n-p掺杂三种结构.利用Crosslight软件,对原始结构和有源区掺杂的三种结构进行仿真研究,比较四种结构的P-I特性曲线、V-I特性曲线、载流子浓度、辐射复合速率和... 详细信息

为了改善深紫外激光二极管的性能,本文提出了有源区量子势垒n掺杂、p掺杂和n-p掺杂三种结构.利用Crosslight软件,对原始结构和有源区掺杂的三种结构进行仿真研究,比较四种结构的P-I特性曲线、V-I特性曲线、载流子浓度、辐射复合速率和能带图.仿真结果表明,有源区量子势垒n-p掺杂结构的性能更优,其阈值电压和阈值电流分别为4.40V和23.8mA;辐射复合速率达到1.64×10^(28)cm^(-3./s;同一注入电流下电光转换效率达到42.1%,比原始结构增加了3.9%;改善了深紫外激光二极管的工作性能.

关键词： AlGaN 有源区量子势垒掺杂深紫外激光二极管

Large-scale phase retrieval

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eLight 2021年第1期1卷 34-45页

作者： Xuyang Chang Liheng Bian jun zhang school of information and electronics&Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijingChina

High-throughput computational imaging requires efficient processing algorithms to retrieve multi-dimensional and multi-scale *** computational phase imaging,phase retrieval(PR)is required to reconstruct both amplitude and phase in complex space from intensity-only *** existing PR algorithms suffer from the tradeoff among low computational complexity,robustness to measurement noise and strong generalization on different *** this work,we report an efficient large-scale phase retrieval technique termed as *** extends the plug-and-play generalized-alternating-projection framework from real space to nonlinear complex *** alternating projection solver and enhancing neural network are respectively derived to tackle the measurement formation and statistical prior *** framework compensates the shortcomings of each operator,so as to realize high-fidelity phase retrieval with low computational complexity and strong *** applied the technique for a series of computational phase imaging modalities including coherent diffraction imaging,coded diffraction pattern imaging,and Fourier ptychographic *** simulations and experiments validate that the technique outperforms the existing PR algorithms with as much as 17dB enhancement on signal-to-noise ratio,and more than one order-of-magnitude increased running ***,we for the first time demonstrate ultralarge-scale phase retrieval at the 8K level(7680×43.0 pixels)in minute-level time.

关键词： Phase retrieval Computational imaging Phase imaging Large scale

基于TC275的质子交换膜燃料电池控制器设计

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现代电子技术 2024年第18期47卷 22-28页

作者：黄文辉于庆瑞王军张景峰孙娜董海鹰甘肃长城氢能源工程研究院有限公司甘肃天水741000 兰州交通大学新能源与动力工程学院甘肃兰州730000

为提高质子交换膜燃料电池系统的能量转换效率,减少研发成本,通过分析燃料电池控制系统的功能需求,设计一种基于英飞凌TC275微处理器的燃料电池智能控制器。该控制器采集所供给燃料的温度、湿度、压力、流量,以及电堆运行时的温度、压... 详细信息

为提高质子交换膜燃料电池系统的能量转换效率,减少研发成本,通过分析燃料电池控制系统的功能需求,设计一种基于英飞凌TC275微处理器的燃料电池智能控制器。该控制器采集所供给燃料的温度、湿度、压力、流量,以及电堆运行时的温度、压力和输出的电压、电流等参量,根据负载功率需求,经过智能算法实时计算后,输出相应的控制指令来调节流量计等执行器件,维持燃料电池系统智能高效、安全稳定的运行;此外,该控制器采用RS 485通信,实现燃料电池系统与上位机之间的信息交互,并实时控制燃料电池系统的运行工况。将该控制器应用于3.kW的质子交换膜燃料电池系统,其监控性能良好、运行稳定可靠,并与建立的仿真模型进行对比,实验结果一致,满足燃料电池系统的控制要求。

关键词：质子交换膜燃料电池智能控制器 TC275 微处理器 RS 485通信信息交互电路设计

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Determination of inter-satellite relative position using X-ray pulsars

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Journal of Zhejiang University-Science C(Computers and electronics) 2013年第2期14卷 133-142页

作者： Da-jun FENG Lu-ping XU Hua zhang Shi-bin SONG school of Electronic engineering Xidian University Institute of astronautics and aeronautics Xidian University

Pulsars are rapidly rotating neutron stars that generate pulsed electromagnetic radiation.A new method for intersatellite relative position determination between a global navigation satellite system(GNSS) and spacecraft using X-ray pulsars is proposed in this *** geometric model of this method is formulated,and two different resolution algorithms are introduced and *** phase cycle ambiguity resolution is investigated,and a new strategy is proposed and *** the direct vector parameters of the pulsar,geometric dilution of precision(GDOP) is *** is shown that this method has advantages of simplicity and efficiency,and is able to eliminate the clock *** analytical results are verified numerically via computer simulations.

关键词： Pulsar navigation Position determination Phase cycle ambiguity Geometric dilution of precision(GDOP)

Line defects in monolayer TiSe_(2) with adsorption of Pt atoms potentially enable excellent catalytic activity

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Nano Research 2022年第5期15卷 4687-4692页

作者： Zhipeng Song Juxia Yi Jing Qi Qi Zheng Zhili Zhu Lei Tao Yun Cao Yan Li Zhaoyan Gao Ruizi zhang Li Huang Geng Li Ziqiang Xu Xu Wu Yeliang Wang Chengmin Shen Yu-Yang zhang Hongliang Lu Xiao Lin Shixuan du Hong-{3. Gao Institute of Physics and University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100190China CAS Center for Excellence in Topological Quantum Computation Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China school of information and electronics Beijing Institute of TechnologyBeijing 100081China

Two-dimensional(2D)materials with defects are desired for catalysis after the adsorption of monodispersed noble metal ***-performance catalysts with the absolute value of Gibbs free energy(|△GH|)close to zero,is one of the ultimate goals in the catalytic ***,we report the formation of monolayer titanium selenide(TiSe2)with line *** low-temperature scanning tunneling microscopy/spectroscopy(STM/S)measurements revealed the structure and electronic states of the line *** functional theory(DFT)calculation results confirmed that the line defects were induced by selenium vacancies and the STM simulation was in good agreement with the experimental ***,DFT calculations show that monolayer TiSe_(2) with line defects have good catalytic activity for hydrogen evolution reaction(HER).If the defects are decorated with single Pt atom,the HER catalytic activity will be enhanced dramatically(|△GH|=0.006 eV),which is much better than Pt metal(|△GH|=0.09 eV).Line defects in monolayer TiSe_(2)/Au(111)provide a wonderful platform for the design of high-performance catalysts.

关键词： line defects hydrogen evolution reaction monolayer titanium selenide(TiSe_(2)) scanning tunneling microscope density functionaltheorycalculation

Robust leaderless time-varying formation control for unmanned aerial vehicle swarm system with Lipschitz nonlinear dynamics and directed switching topologies

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Chinese Journal of aeronautics 2022年第1期35卷 124-136页

作者： Yuhang KANG Yu KUANG jun CHENG Bangchu zhang Yahui QI Shaolei ZHOU Kai MAO Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China school of Basic Science Naval Aviation UniversityYantai 264001China school of aeronautics and astronautics Sun Yat-Sen UniversityGuangzhou 510275China

This paper tackles the robust leaderless Time-Varying Formation(TVF)control problem for the Unmanned Aerial Vehicle(UAV)swarm system with Lipschitz nonlinear dynamics,external disturbances and directed switching *** comparison with the previous achievements on formation control problems,the UAV swarm system with Lipschitz nonlinear dynamics can accomplish the pre-designed TVF while tracking a pre-given trajectory which is produced by a virtual leader UAV in the presence of external ***,by applying the consensus theory,a TVF controller is developed with the local neighborhood status information,the errors of real time status of all UAVs,the expected formation configuration and the pre-given trajectory under directed switching ***,through a certain matrix variable substitution,the UAV swarm system formation control issue is transformed into a lower dimensional asymptotically stable control ***,by introducing the minimum dwell time,the design steps of formation control algorithm are further *** the meantime,the stability of the UAV swarm system is analyzed through the construction of a piecewise continuous Lyapunov functional and via the Linear Matrix Inequalities(LMIs)***,the comparison results of a numerical simulation are elaborated to verify the validity of the proposed approach.

关键词： Directed switching topologies Lipschitz nonlinear dynamics Lyapunov functional Swarm system Time-Varying Formation(TVF) Unmanned Aerial Vehicle(UAV)

A Compact Ultra-Wideband Circularly Polarized Antenna Array for Vehicular Communications

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china Communications 2023年第6期20卷 310-320页

作者： Wei He Yejun He Long zhang jun Hong Haixia Cui Amir Boag school of Electrical and information engineering Hunan Institute of TechnologyHengyang 421002China College of electronics and information engineering Shenzhen UniversityShenzhen 518060China school of Physics and Telecommunication engineering South China Normal UniversityGuangzhou 510630China school of Electrical engineering Tel Aviv UniversityTel Aviv 69978Israel

In this paper,a new compact ultrawideband(UWB)circularly polarized(CP)antenna array for vehicular communications is *** antenna array consists of a 2×2 sequentially rotated T-shaped cross dipole,four parasitic elements,and a feeding *** loading the T-shaped cross dipoles with parasitic rectangular elements with cut corners,the bandwidth can be *** this basis,the radiation pattern can be improved by the topology with sequential rotation of four T-shaped cross-dipole antennas,and the axial ratio(AR)bandwidth of the antenna also can be further *** addition,due to the special topology that the vertical arms of all Tshaped cross dipoles are all oriented toward the center of the antenna array,the gain of proposed antenna is improved while the size of the antenna is almost the same as the traditional cross *** and measured results show that the proposed antenna has good CP characteristics,an impedance bandwidth for S113.26:1,1.57-5.12 GHz)and the 3.d B AR bandwidth of about 104.1%(3.17:1,1.57-4.98 GHz),a wide 3.d B gain bandwidth of 73.3.as well as the peak gain of 8.6 d Bic at 3.5 *** overall size of antenna is 0.56λ×0.56λ×0.12λ(λrefers to the wavelength of the lowest operating frequency in free space).The good performance of this compact UWB CP antenna array is promising for applications in vehicular communications.

关键词： circularly polarized antenna vehicle satellite communications cross-dipole antenna ultrawideband(UWB)antenna

A Novel Orthogonal LoRa Multiple Access Algorithm for Satellite Internet of Things

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china Communications 2022年第3期19卷 279-289页

作者： Chengwen zhang Liankai Wang Libin Jiao Shipeng Wang jun Shi Jia Yue school of electronics and information {3. Harbin Institute of TechnologyHarbin 150080China Science and Technology on Communication Networks Laboratory Shijiazhuang 050081China Key Laboratory of Police Wireless Digital Communication Ministry of Public SecurityHarbin 150001China

In recent years,LoRa has been extensively researched in the satellite Internet of Things(IoT).However,the multiple access technology of LoRa is still one of the bottlenecks of satellite *** improve the multiple access performance of LoRa satellite IoT,based on the orthogonality of LoRa symbols in the fractional domain,this paper proposes a low complexity Orthogonal LoRa Multiple Access(OLMA)algorithm for multiple LoRa users occupying the same frequency *** algorithm introduces the address code to divide the fractional bandwidth into multiple parts,and the OLMA users with different address codes occupy different parts to transmit the information code,thus avoiding mutual interference caused by collisions in the same frequency *** multiple access capability of OLMA can be flexibly configured only by simply adjusting the length of the address code according to the actual application requirements of data *** analysis and simulation results show that the OLMA algorithm can greatly improve the multiple access capability and the total transmission bit rate of LoRa IoT without changing the existing LoRa modulation parameters and process.

关键词： LoRa satellite Internet of Things multiple access fractional domain linear frequency modulation

Defect engineering in g‑C_(3.N_(4)Quantum‑Dot‑Modified TiO_(2)Nanofiber:Uncovering Novel Mechanisms for the Degradation of Tetracycline in Coexistence with Cu^(2+)

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Advanced Fiber Materials 2023年第1期5卷 168-182页

作者： Jingzhe zhang Xin Wang Kaixiang Shen Wenjing Lu jun Wang Fuming Chen Guangdong Provincial Key Laboratory of Quantum engineering and Quantum Materials Guangdong Engineering Technology Research Center of Efficient Green Energy and Environment Protection MaterialsSchool of Physics and Telecommunication EngineeringSouth China Normal UniversityGuangzhou 510006China school of Electrical engineering and Automation Wuhan UniversityWuhan 430000China school of electronics and information {3. South China Normal UniversityFoshan 528225China

Herein,g-C_(3.N_(4)quantum-dot-modified TiO_(2)nanofibers were fabricated and used as an efficient photocatalyst for the investigation of the influence of Cu^(2+)and the interaction mechanism between Cu^(2+)and surface defects in tetracycline *** showed that the effect of Cu^(2+)switched from promoting to inhibiting the tetracycline degradation as the amount of Cu^(2+)accumulated on the catalyst surface *** introduction of surface defects can prevent the inhibiting effect of Cu^(2+),resulting in the more complete degradation of tetracycline in contrast to the non-defective *** calculations further revealed that the defects can be used to tune the conduction band of the composite,inducing the reduction reaction of Cu^(2+)and inhibiting the accumulation of Cu on the surface of ***,the Cu introduced to the catalyst surface provided new active sites,thereby promoting photocatalytic *** findings provide new insights into the design of advanced fiber materials for water purification in complex environments.

关键词： Tetracycline Cu^(2+) C_(3.N_(4) TiO_(2) Defect