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Chinese physics b 2022年第6期31卷 678-682页

作者： Ying-Zhe Wang Mao-Sen Wang Ning Hua Kai Chen Zhi-Min He Xue-Feng Zheng Pei-Xian li Xiao-Hua Ma li-xin Guo Yue Hao key laboratory of Wide bandgap Semiconductor Materials and Devices School of MicroelectronicsXidian UniversityXi’an 710071China Shanghai Aerospace Electronic Technology Institute Shanghai 201109China school of Advanced Materials and Nanotechnology Xidian UniversityXi’an 710071China school of physics and Optoelectronic engineering Xidian UniversityXi’an 710071China

The degradation mechanism of GaN-based near-ultraviolet(NUV,3.0-400 nm)light emitting diodes(LEDs)with low-indium content under electrical stress is studied from the aspect of defects.A decrease in the optical power and an increase in the leakage current are observed after electrical *** defect behaviors are characterized using deep level transient spectroscopy(DLTS)measurement under different filling pulse *** stress,the concentration of defects with the energy level of 0.47-0.56 eV increases,accompanied by decrease in the concentration of 0.72-0.84 eV *** the defect energy level with the increased yellow luminescence in photoluminescence spectra,the device degradation can be attributed to the activation of the gallium vacancy and oxygen related complex defect along dislocation,which was previously passivated with *** study reveals the evolution process of defects under electrical stress and their spatial location,laying a foundation for manufacture of GaN-based NUV LEDs with high reliability.

关键词： light emitting diodes GaN electrical stress defect

Detection and Classification of Transmission line transient Faults based on Graph Convolutional Neural Network

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CSEE Journal of power and Energy Systems 2021年第3期7卷 456-471页

作者： Houjie Tong Robert C.Qiu Dongxia Zhang Haosen Yang Qi Ding xin Shi Department of Electrical engineering Center for Big Data and Artificial IntelligenceShanghai Jiao Tong UniversityShanghai 200240China school of Electronic Information and Communication Huazhong University of Science and TechnologyWuhan 430000China Electric power Research Institute Haidian DistrictBeijing 100192China school of Control and Computer engineering North China Electric Power UniversityBeijing 102206China

We present a novel transient fault detection and classification approach in power transmission lines based on graph convolutional neural *** with the existing techniques,the proposed approach considers explicit spatial information in sampling sequences as prior knowledge and it has stronger feature extraction *** this basis,a framework for transient fault detection and classification is *** structure is generated to provide topology information to the *** approach takes the adjacency matrix of topology graph and the bus voltage signals during a sampling period after transient faults as inputs,and outputs the predicted classification results ***,the proposed approach is tested in various situations and its generalization ability is verified by experimental *** results show that the proposed approach can detect and classify transient faults more effectively than the existing techniques,and it is practical for online transmission line protection for its rapidness,high robustness and generalization ability.

关键词： Graph convolutional network(GCN) power transmission line fault detection and classification spatio-temporal data topology information

Experimental study on flow control of the turbulent boundary layer with micro-bubbles

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Acta Mechanica Sinica 2018年第5期34卷 830-838页

作者： Peng-Long Zhao Yao-Hui Chen Gang Dong Yi-xin liu Xu-Jian Lyu key laboratory of transient {3. Nanjing University of Science and TechnologyNanjing 210094China school of Energy and power engineering Nanjing University of Science and TechnologyNanjing 210094China

The effect of micro-bubbles on the turbulent boundary layer in the channel flow with Reynolds numbers (Re) ranging from 0.87 × 105 to 1.23.× 105 is experimentally studied by using particle image velocimetry (PIV) *** microbubbles are produced by water *** velocity profiles,Reynolds stress and instantaneous structures of the boundary layer,with and without micro-bubbles,are measured and *** presence of micro-bubbles changes the streamwise mean velocity of the fluid and increases the wall shear *** results show that micro-bubbles have two effects,buoyancy and extrusion,which dominate the flow behavior of the mixed fluid in the turbulent boundary *** buoyancy effect leads to upward motion that drives the fluid motion in the same direction and,therefore,enhances the turbulence intense of the boundary *** for the extrusion effect,the presence of accumulated micro-bubbles pushes the flow structures in the turbulent boundary layer away from the near-wall *** interaction between these two effects causes the vorticity structures and turbulence activity to be in the region far away from the *** buoyancy effect is dominant when the Re is relatively small,while the extrusion effect plays a more important role when Re rises.

关键词： PIV Micro-bubbles Turbulent boundary layer Reynolds stress

An integral calculation approach for numerical simulation of cavitating flow around a marine propeller behind the ship hull

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Journal of Hydrodynamics 2018年第6期30卷 1186-1189页

作者： Cheng-zao Han Yun Long bin Ji xin-ping Long Zhi-rong Zhang State key laboratory of Water Resources and Hydropower {3. science Wuhan University school of power and Mechanical engineering Wuhan University national key laboratory on Ship Vibration and Noise China Ship Scientific Research Center

In this paper, the unsteady cavitating turbulent flow around a marine propeller is simulated based on the unsteady Reynolds averaged Navier-Stokes(URANS) with emphasis on the hull-propeller interaction by an integral calculation approach, which means the propeller and hull are treated as a whole when the cavitating flow is calculated. The whole calculational domain is split to an inner rotating domain containing a propeller and an outer domain containing a hull. And the two split sections are connected together in ANSYS CFX by using the GGI interfaces and the transient rotor stator frame change/mi{3.g model. The alternate rotation model is employed for the advection term in the momentum equations in order to reduce the numerical error. Comparison of predictions with measurements shows that the propeller thrust coefficient can be predicted satisfactorily. The unsteady cavitating flow around the propeller behind the ship hull wake shows quasi-periodic features including cavity inception, growth and shrinking. These features are effectively reproduced in the simulations which compare well to available experimental data. In addition, significant pressure fluctuations on the ship hull surface induced by the unsteady propeller cavitation are compared with experimental data at monitoring points on the hull surface. The predicted amplitudes of the first components corresponding to the first blade passing frequencies match well with the experimental data. The maximum error between the predictions and the experimental data for the pressure pulsations is around 8%, which is acceptable in most engineering applications.

关键词： Integral calculation approach cavitating flow hull-propeller interactions pressure fluctuations

带并联电抗器的交流特高压输电线路单相自适应重合闸故障识别方法(英文)

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高电压技术 2013年第4期39卷 769-775页

作者： liN xin XIE Yinzhi SUI Dongpeng XU Jianyuan liU Yang school of Electrical engineering Shenyang University of Technology liaoning Province key Lab of power Grid Safe Operation and Monitoring

In order to avoid single-phase adaptive reclosure overlap in a permanent fault,accurate identification of the fault types on transmission line is *** present a fault nature identification method for ultra-high voltage alternating current(UHVAC) transmission lines with shunt *** voltage amplitude ratios of the neutral small reactance voltage to terminal voltage under {3. fault and permanent fault are *** significant differences of the ratio under the two faults have been *** is found that the ratio can be a criterion to distinguish the fault type,{3. or permanent,***,we also proposed a method that delays a beat frequency oscillation cycle to decide the fault types for the existence of beat frequency oscillation which will cause misidentification on {3. *** simulation results of ATP/EMTP show that the voltage amplitude ratio under {3. fault is between 0.6 and 0.7,which is bigger than 2.5,the ratio under permanent fault.

关键词：单相自适应重合闸特高压输电线路高压并联电抗器识别方法故障性质永久性故障故障类型瞬态故障

一种基于集总电荷的大功率PIN二极管改进电路模型

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电工技术学报 2019年第3期34卷 506-515页

作者：李鑫罗毅飞段耀强刘宾礼黄永乐海军工程大学舰船综合电力技术国防科技重点实验室武汉430033 华中科技大学电气与电子工程学院武汉430074

提出了一种基于集总电荷建模方法的大功率PIN二极管改进电路模型。传统的集总电荷模型使用有效载流子寿命模型,未考虑载流子寿命和基区电荷浓度之间的关系,导致模型的仿真精度偏低。该文在研究传统PIN二极管集总电荷模型的基础上,首先... 详细信息

提出了一种基于集总电荷建模方法的大功率PIN二极管改进电路模型。传统的集总电荷模型使用有效载流子寿命模型,未考虑载流子寿命和基区电荷浓度之间的关系,导致模型的仿真精度偏低。该文在研究传统PIN二极管集总电荷模型的基础上,首先分析了二极管基区载流子寿命随注入浓度和温度的变化规律,并提出了载流子寿命随浓度和温度变化的集总电荷模型。然后,基于提出的载流子寿命模型建立了改进的PIN二极管集总电荷电路模型,并加入模型物理参数的温度函数,实现了模型对不同温度下PIN二极管通态和瞬态特性的表征,并在PSPICE仿真平台中实现了该模型。最后,用1 700 V/1 000 A IGbT模块中反并联续流二极管对模型进行了实验,仿真和实验结果对比验证了该模型的准确性。

关键词： PIN二极管集总电荷模型温度特性过剩载流子寿命

Simultaneous polarization separation and switching for 100-Gbps DP-QPSK signals in backbone networks

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Chinese physics b 2019年第2期28卷 299-305页

作者： Yu-Long Su Huan Feng Hui Hu Wei Wang Tao Duan Yi-Shan Wang Jin-Hai Si Xiao-Ping Xie He-Ning Yang xin-Ning Huang State key laboratory of transient Optics and Photonics Xi'an Institute of Optics and Precision MechanicsChinese Academy of Sciences key laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi key laboratory of Information Photonic Technique School of Electronic and Information EngineeringXi'an Jiaotong University university of Chinese Academy of sciences

We propose a novel scheme of simultaneous polarization separation and switching, based on the orthogonallypolarized four-wave mixing(FWM) effect, for ultra-high-speed polarization multiplexing(Pol-MUX) fiber networks such as 100-Gbps and 400-Gbps backbone networks. We use theoretical and experimental analysis of the vector theory of FWM to successfully achieve polarization separation and all-optical switching by utilizing a 100-Gbps dual polarizationquadrature phase shift {3.ing(DP-QPSK) signal and two orthogonally-polarized pumps. both of the polarization-separated QPSK signals have clear constellation diagrams, with root mean square(RMS) error vector magnitudes(EVMs) of 14.3.%and 14.11% respectively. The wavelengths of idlers can be created at 3. different wavelengths, which are consistent with International Telecommunication Union-Telecommunication(ITU-T) wavelengths, by flexibly changing the wavelength of the pump light. Moreover, the idlers that have distinct wavelengths have power distributed in a range from-10 dbm to-15 dbm, which can support error-free transmission. The power penaltyis 5 d b lower than that of back-to-back(bTb)signal for both the X-and Y-polarization components measured at a bit error ratio(bER) of 3.8×10^(-3.. Our experimental results indicate that this scheme has promising applications in future backbone networks.

关键词： polarization separation and switching four-wave mixing orthogonal polarization 100-Gbps dual polarization-quadrature phase shift keying

Efficient thermal dissipation in wafer-scale heterogeneous integration of single-crystalline𝛽β-Ga_(2)O_(3.thin film on SiC

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Fundamental Research 2021年第6期1卷 691-696页

作者： Wenhui Xu Tiangui You Yibo Wang Zhenghao Shen Kang liu lianghui Zhang Huarui Sun Ruijie Qian Zhenghua An Fengwen Mu Tadatomo Suga Genquan Han xin Ou Yue Hao Xi Wang State key laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China The State key Discipline laboratory of Wide band Gap Semiconductor Technology School of MicroelectronicsXidian UniversityXi’an 710071China school of science and Ministry of Industry and Information Technology key {3. of Micro-Nano Optoelectronic Information System Harbin Institute of TechnologyShenzhen 518055China Department of physics State Key Laboratory of Surface PhysicsInstitute of Nanoelectronic Devices and Quantum ComputingFudan UniversityShanghai 200433China High-Frequency High-Voltage Device and Integrated Circuits R&D Center Institute of MicroelectronicsChinese Academy of SciencesBeijing 100029China Collaborative Research Center Meisei UniversityHinoJapan Center of Materials science and Optoelectronics engineering University of Chinese Academy of SciencesBeijing 100049China

The semiconductor,β-Ga_(2)O_(3.is attractive for applications in high power electronic devices with low conduction loss due to its ultra-wide bandgap(∼4.9 eV)and large baliga’s figure of ***,the thermal conductivity of𝛽β-Ga_(2)O_(3.is much lower than that of other wide/ultra-wide bandgap semiconductors,such as SiC and GaN,which results in the deterioration of𝛽β-Ga_(2)O_(3.-based device performance and reliability due to *** overcome this problem,a scalable thermal management strategy was proposed by heterogeneously integrating wafer-scale single-crystalline𝛽β-Ga_(2)O_(3.thin films on a highly thermally conductive SiC *** of the transferred𝛽β-Ga_(2)O_(3.thin film indicated a uniform thickness to within±2.01%,a smooth surface with a roughness of 0.2 nm,and good crystalline quality with an X-ray rocking curves(XRC)full width at half maximum of 80 *** thermoreflectance measurements were employed to investigate the thermal *** thermal performance of the fabricated𝛽β-Ga_(2)O_(3./SiC heterostructure was effectively improved in comparison with that of the𝛽β-Ga_(2)O_(3.bulk wafer,and the effective thermal boundary resistance could be further reduced to 7.5 m 2 K/GW by a post-annealing *** barrier diodes(SbDs)were fabricated on both a𝛽β-Ga_(2)O_(3./SiC heterostructured material and a𝛽β-Ga_(2)O_(3.bulk *** thermal imaging revealed the temperature increase of the SbDs on𝛽β-Ga_(2)O_(3./SiC to be one quarter that on the𝛽β-Ga_(2)O_(3.bulk wafer with the same applied power,which suggests that the combination of the𝛽-Ga_(2)O_(3.thin film and SiC substrate with high thermal conductivity promotes heat dissipation in𝛽β-Ga_(2)O_(3.-based devices.

关键词： Thermal management Heterogeneous integration Wafer scale𝛽β-Ga_(2)O_(3.on SiC Ion-cutting technique Schottky barrier diodes(SbDs) transient thermoreflectance(TTR) measurements

Compact CubeSat Gamma-ray detector for GRID mission

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Nuclear science and Techniques 2021年第9期32卷 105-115页

作者： Jia-xing Wen Xu-Tao Zheng Jian-Dong Yu Yue-Peng Che Dong-xin Yang Huai-Zhong Gao Yi-Fei Jin Xiang-Yun Long Yi-Hui liu Da-Cheng Xu Yu-Chong Zhang Ming Zeng Yang Tian Hua Feng Zhi Zeng Ji-Rong Cang Qiong Wu Zong-Qing Zhao bin-bin Zhang Peng An GRID collaboration key laboratory of Particle and Radiation Imaging(Tsinghua university) Ministry of EducationBeijing 100084China Department of engineering physics Tsinghua UniversityBeijing 100084China science and Technology on Plasma physics laboratory Laser Fusion Research CenterCAEPMianyang 621900China school of Electronic and Information engineering Ningbo University of TechnologyNingbo 315201China Department of Astronomy Tsinghua UniversityBeijing 100084China Department of physics Tsinghua UniversityBeijing 100084China key laboratory of Modern Astronomy and Astrophysics({3. university) Ministry of EducationNanjing 210093China nanjing university School of Astronomy and Space SciencesNanjing 210093China

Gamma-Ray Integrated Detectors(GRID)mis-sion is a student project designed to use multiple gamma-ray detectors carried by nanosatellites(CubeSats),forming a full-time all-sky gamma-ray detection network that monitors the transient gamma-ray sky in the multi-mes-senger astronomy era.A compact CubeSat gamma-ray detector,including its hardware and firmware,was designed and implemented for the *** detector employs four Gd 2 Al 2 Ga 3.O 12:Ce(GAGG:Ce)scintillators coupled with four silicon photomultiplier(SiPM)arrays to achieve a high gamma-ray detection efficiency between 10 keV and 2 MeV with low power and small *** first detector designed by the undergraduate student team onboard a commercial CubeSat was launched into a Sun-synchronous orbit on October 29,*** detector was in a normal observation state and accumulated data for approximately one month after on-orbit functional and performance tests,which were conducted in 2019.

关键词： Gamma-ray bursts Scintillation detectors SiPM CubeSat

NiO/Ga_(2)O_(3. p+-n异质结功率二极管中陷阱介导双极型电荷输运研究

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science china Materials 2023年第3期66卷 1157-1164页

作者：汪正鹏巩贺贺郁鑫鑫纪晓丽任芳芳杨燚顾书林郑有炓张荣叶建东 school of Electronic science and engineering Nanjing UniversityNanjing 210023China Shenzhen Research Institute of Shandong university Shenzhen 518000China

构筑NiO/Ga_(2)O_(3.p+-n异质结是克服Ga_(2)O_(3.p型掺杂瓶颈从而实现双极型功率电子器件的有效途径,然而限制器件性能的缺陷行为与双极型电荷输运等物理机制尚不明晰.本论文研究了NiO/Ga_(2)O_(3.p+-n异质结中陷阱介导的载流子输运、... 详细信息

构筑NiO/Ga_(2)O_(3.p+-n异质结是克服Ga_(2)O_(3.p型掺杂瓶颈从而实现双极型功率电子器件的有效途径,然而限制器件性能的缺陷行为与双极型电荷输运等物理机制尚不明晰.本论文研究了NiO/Ga_(2)O_(3.p+-n异质结中陷阱介导的载流子输运、俘获和复合动力学之间的内在关联特性.变温电流-电压特性的量化分析表明,在正偏亚阈值区,陷阱辅助隧穿占据主导地位,符合多数载流子陷阱介导的Shockley-Read-Hall复合模型,其陷阱激活能为0.64 eV,与深能级瞬态谱测试的陷阱能级位置(EC-0.67 eV)非常吻合;当正向偏压大于器件开启电压时,器件输运特性由少数载流子扩散所主导,器件理想因子接近于1.在反向偏置的高场作用下,器件漏电机制则由β-Ga_(2)O_(3.体材料中的陷阱引起的PooleFrenkel(PF)发射所导致.PF发射的势垒高度为0.75 eV,与等温变频深能级瞬态谱测得的陷阱能级位置(EC-0.75 eV)相一致.这一工作有助于建立NiO/Ga_(2)O_(3.p+-n异质结中双极型电荷输运和深能级缺陷行为间的内在关联,对理解和发展Ga_(2)O_(3.双极型功率整流器件具有重要的参考价值.

关键词：深能级瞬态谱双极型功率电子器件电荷输运功率二极管载流子输运开启电压亚阈值区