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The temperature dependence of optical properties of InGaN alloys

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Science China(Physics,Mechanics & Astronomy) 2012年第3期55卷 396-399页

作者： ZHAO ChuanZhen ZHANG Rong LIU Bin fu deyi CHEN Hui LI Ming XIE ZiLi XIU XiangQian GU ShuLin ZHENG YouDou Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials Department of PhysicsNanjing National Laboratory of MicrostructuresNanjing UniversityNanjing 210093China School of Information and Communication Engineering Tianjin Polytechnics UniversityTianjin 300160China

In our experiments,the PL spectra of several In x Ga 1 x N alloy samples with In contents x=0.1,0.15 and 0.25 were measured as a function of temperature ranging from 10 K to 300 K.S-shaped temperature dependencies were observed in all InGaN samples and a sharp decrease in the full width at half maximum occurred with decreasing temperature in the moderate temperature *** was found that both phenomena are relative to localization *** addition,the degree of localization effects in three samples was investigated using the band-tail *** findings are presented in this paper.

关键词： InGaN photoluminescence full width at half maximum

Temperature dependence of the point defect properties of GaN thin films studied by terahertz time-domain spectroscopy

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Science China(Physics,Mechanics & Astronomy) 2013年第11期56卷 2059-2064页

作者： FANG HeNan ZHANG Rong LIU Bin LI YeCao fu deyi LI Yi XIE ZiLi ZHUANG Zhe ZHENG YouDou WU JingBo JIN BiaoBing CHEN Jian WU PeiHeng Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronics Science and EngineeringNanjing National Laboratory of MicrostructureNanjing University Research Institute of Superconductor Electronics School of Electronic Science and EngineeringNanjing National Laboratory ofMicrostructureNanjing University

The dielectric functions of GaN for the temperature and frequency ranges of 10–300 K and 0.3–1 THz are obtained using terahertz time-domain *** is found that there are oscillations of the dielectric functions at various ***,the oscillation behavior is attributed to the resonance states of the point defects in the ***,the dielectric functions are well fitted by the combination of the simple Drude model together with the classical damped oscillator *** to the values of the fitting parameters,the concentration and electron lifetime of the point defects for various temperatures are determined,and the temperature dependences of them are in accordance with the previously reported ***,terahertz time-domain spectroscopy can be considered as a promising technique for investigating the relevant characteristics of the point defects in semiconductor materials.

关键词： THz time-domain spectroscopy GaN film temperature dependence

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基于AE与STFT的变桨轴承裂纹诊断研究

振动．测试与诊断 2021年第2期41卷 299-303,412页

作者：李婷付德义薛扬中国电力科学研究院有限公司新能源研究中心北京100192 中国电力科学研究院有限公司新能源与储能运行控制国家重点实验室北京100192

由于变桨轴承不完全转动的工作特殊性,基于振动或应变等常规监测手段难以奏效,为此提出一种基于声发射(acoustic emission,简称AE)技术监测方法获取信号,并采用短时傅里叶方法(short time Fourier transform,简称STFT)进行分析诊断的方... 详细信息

由于变桨轴承不完全转动的工作特殊性,基于振动或应变等常规监测手段难以奏效,为此提出一种基于声发射(acoustic emission,简称AE)技术监测方法获取信号,并采用短时傅里叶方法(short time Fourier transform,简称STFT)进行分析诊断的方法。首先,研究了AE技术的信号采集方法,推导了STFT的原理及过程,并在某风电机组变桨轴承上进行实验验证;其次,先后在时域、频域及时频域对有裂纹数据和无裂纹数据进行对比,发现时频域基于STFT分析方法可以有效发现裂纹;最后,通过新的裂纹数据进行验证,可以确认裂纹特征。结果表明:AE信号能较好地获取变桨轴承的状态信息,STFT分析方法可以较好地识别裂纹故障,较少受工况或其他因素的影响,有较高的实用价值。

关键词：声发射技术短时傅里叶变桨轴承裂纹诊断风电机组

Ship collision impact on the structural load of an offshore wind turbine

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Global Energy Interconnection 2020年第1期3卷 44-51页

作者： Haikun Jia Shiyao Qin Ruiming Wang Yang Xue deyi fu Anqing Wang State Key Laboratory of Operation and Control of Renewable Energy&Storage Systems China Electric Power Research InstituteP.R.China

When a maintenance and operations ship is berthing,there is a chance the ship may collide into the wind *** these ships collide into wind turbine structures,this can result in significant changes to the foundation and structure of the wind *** this paper,the structural load of a 4 MW offshore wind turbine was analyzed during a collision with an operations and maintenance *** variations in the wind speeds on hub height,waves,and the sea currents were *** dynamic simulation of the wind turbine was carried out using the test data as the input *** a result,the load condition of the turbine without a collision was ***,the measured turbine load was compared with the simulation *** study shows that the collision of the operation and the maintenance ship increases the bending moments at the tower’s bottom and the blade’s roots.

关键词： Offshore wind turbine Ship collision Offshore experiment Wind-wave-current coupling filed

A 4H-SiC semi-super-junction shielded trench MOSFET: p-pillar is grounded to optimize the electric field characteristics

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Journal of Semiconductors 2022年第12期43卷 79-87页

作者： Xiaojie Wang Zhanwei Shen Guoliang Zhang Yuyang Miao Tiange Li Xiaogang Zhu Jiafa Cai Rongdun Hong Xiaping Chen Dingqu Lin Shaoxiong Wu Yuning Zhang deyi fu Zhengyun Wu Feng Zhang College of Physical Science and Technology Xiamen UniversityXiamen 361005China Key Laboratory of Semiconductor Material Sciences Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Shenzhen Research Institute of Xiamen University Shenzhen 518057China Jiujiang Research Institute of Xiamen University Jiujiang 332000China

A 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor(UMOSFET)with semi-super-junction shiel-ded structure(SS-UMOS)is proposed and compared with conventional trench MOSFET(CT-UMOS)in this *** advantage of the proposed structure is given by comprehensive study of the mechanism of the local semi-super-junction structure at the bottom of the trench *** particular,the influence of the bias condition of the p-pillar at the bottom of the trench on the static and dynamic performances of the device is compared and *** on-resistance of SS-UMOS with grounded(G)and ungrounded(NG)p-pillar is reduced by 52%(G)and 71%(NG)compared to CT-UMOS,***,gate ox-ide in the GSS-UMOS is fully protected by the p-shield layer as well as semi-super-junction structure under the trench and p-base ***,a reduced electric-field of 2 MV/cm can be achieved at the corner of the p-shield ***,the quasi-intrinsic protective layer cannot be formed in NGSS-UMOS due to the charge storage effect in the floating p-pillar,resulting in a large electric field of 2.7 MV/cm at the gate oxide ***,the total switching loss of GSS-UMOS is 1.95 mJ/cm2 and is reduced by 18%compared with *** the contrary,the NGSS-UMOS has the slowest overall switching speed due to the weakened shielding effect of the p-pillar and the largest gate-to-drain capacitance among the *** proposed GSS-UMOS plays an important role in high-voltage and high-frequency applications,and will provide a valuable idea for device design and circuit applications.

关键词： breakdown voltage specific on-resistance silicon carbide switching energy loss super-junction-shield(SS) trench gate MOSFET grounded(G) ungrounded(NG)

A Digital Controller Design Method to Improve Performance of PFC Converter

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Energy and Power Engineering 2013年第4期5卷 162-166页

作者： Xiaoqiang Zhang Weiping Zhang Peng Mao deyi fu Beijing Institute of Technology Beijing China North China University of Technology Beijing China North China University of Technology Beijing China

With the rapid development of digital signal processing chip in recent years, DSP began to be used in more switching power supply. The advantages of digital control of their own, making the digital control PFC become a hotspot research. However, compared with the simulation system, the digital control technology still has many problems. In this paper, the problem of digital PI compensator as a voltage compensator is discussed, and the Single-pole voltage loop compensator is used in digital control PFC circuit. Because current loop bandwidth is narrow, a method to expand current loop bandwidth is put forward. Output power 300 W of prototype is made, and experimental results verify the correctness of the theory.

关键词： PI compensator Single-pole Compensator the Bandwidth of Current Loop

The growth and properties of an m-plane InN epilayer on LiAlO_2 (100) by metal-organic chemical vapor deposition

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Science China(Physics,Mechanics & Astronomy) 2012年第7期55卷 1249-1252页

作者： XIE ZiLi ZHANG Rong fu deyi LIU Bin XIU XiangQian HUA XueMei ZHAO Hong CHEN Peng HAN Ping SHI Yi ZHENG YouDou School of Electronics and Engineerings Nanjing UniversityJiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Mate-rialsNational Laboratory of Solid State MicrostructuresNanjing 210093China

The m-plane InN （1 100） epilayers have been grown on a LiAlO2 （1 0 0） substrate by a two-step growth method using a met- al-organic chemical vapor deposition （MOCVD） system. The low temperature InN buffer layer （LT-InN） is introduced to overcome the drawbacks of thermal instability of LiAlO2 （LAO） and to relieve the strains due to a large thermal mismatch be- tween LAO and InN. Then the high temperature m-plane InN （1 1 00） epilayers （HT-InN） were grown. The results of X-ray diffraction （XRD） suggest that the m-plane InN （1 1 00） epilayer is a single crystal. The X-ray rocking curves （co scans）（XRC） and atomic force microscopy （AFM） indicate that the m-plane InN （1 1 00） epilayer has anisotropic crystallographic properties. The PL studies of the materials reveal a remarkable energy band gap structure around 0.70 eV at 15 K.

关键词： crystal structure X-ray diffraction vapor-phase epitaxy InN semiconducting indium compound

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风电机组功率特性劣化监测技术研究

兵器装备工程学报 2021年第11期42卷 215-221页

作者：付德义孔令行中国电力科学研究院有限公司新能源与储能运行控制国家重点实验室北京100192

为实现风电机组长期服役条件下功率输出特性劣化的监测与评估,考虑在同一场址条件下,地理位置相近,系统配置相同的风电机组外部环境条件具有相似性以及功率输出特性呈现强相关性,基于改进的非线性状态估计技术,采用改进欧式距离算法,建... 详细信息

为实现风电机组长期服役条件下功率输出特性劣化的监测与评估,考虑在同一场址条件下,地理位置相近,系统配置相同的风电机组外部环境条件具有相似性以及功率输出特性呈现强相关性,基于改进的非线性状态估计技术,采用改进欧式距离算法,建立风电机组功率特性劣化监测模型。结合某海上风电场风电机组簇实际运行数据,对该劣化监测方法和模型进行了测试。研究结果表明:基于改进非线性状态估计模型的风电机组功率特性劣化监测方法,正常情况下功率输出实际值与预测值的残差在0.5%以内;当风电机组功率输出特性出现劣化时,残差会出现异常并逐渐加大。提出的基于改进非线性状态估计的风电机组功率特性劣化监测方法,对于风电机组预测性运维以及优化技改具有指导意义。

关键词：风电机组功率特性非线性状态估计劣化监测

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财会软件如何应对新会计准则的变化

北京工商大学学报（社会科学版） 2007年第2期22卷 50-54页

作者：吴辉付得一北京工商大学会计学院北京100037

我国2006年2月颁布的新会计准则对财会软件将产生较大的影响。财会软件应对“首次执行企业会计准则”措施是一个较紧急的应对措施,而财会软件应对“所得税准则”、“资产减值准则”、“每股收益准则”、“借款费用准则”等的措施是比较... 详细信息

我国2006年2月颁布的新会计准则对财会软件将产生较大的影响。财会软件应对“首次执行企业会计准则”措施是一个较紧急的应对措施,而财会软件应对“所得税准则”、“资产减值准则”、“每股收益准则”、“借款费用准则”等的措施是比较重要的应对措施。

关键词：会计准则财会软件