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Improved performance of GaN-based light-emitting diodes by using short-period superlattice structures

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Progress in Natural Science:Materials International 2010年第1期20卷 70-75页

作者： Yi-jung LIU~1,Chien-chang HUANG~1,Tai-you CHEN~1,Chi-shiang HSU~1,Shiou-ying CHENG~2, Kun-wei LIN~3.Jian-kai LIOU~1,Wen-chau LIU~1 1.institute of Microelectronics,Department of Electrical engineering,National Cheng-Kung University, Tainan 70101,Taiwan,{3. 2.Department of electronic engineering,Nation Ilan University,I-Lan 26041,Taiwan,{3. 3.Department and Graduate institute of Computer Science and information engineering, Chaoyang University of technology,Taichung 413.9,Taiwan,{3. [a] institute of Microelectronics Department of Electrical Engineering National Cheng-Kung University Tainan 70101 Taiwan China [b] Department of electronic engineering Nation Ilan University I-Lan 26041 Taiwan China [c] Department and Graduate institute of Computer Science and information engineering Chaoyang University of Technology Taichung 41349 Taiwan China

An InGaN/GaN multiple-quantum-well（MQW）light-emitting diode（LED）with a ten-period i（undoped）-InGaN/p（Mg doped）-GaN（2.5 nm/5.0 nm）superlattice（SL）structure,was *** SL structure that can be regarded as a confinement layer of holes to enhance the hole injection efficiency is inserted between MQW and p-GaN *** studied LED device exhibits better current spreading performance and an improved quality,compared with a conventional one without SL *** to the reduced contact resistance as well as more uniformity of carriers injection,the operation voltage at 20 mA is decreased from 3.3. to 3.14 V.A remarkably reduced reverse-biased leakage current(10-7-10-9A)and higher endurance of the reverse current pulse are *** measured output power and external quantum efficiency（EQE）of the studied LED are 13.6 mW and 24.8%,respectively. In addition,significant enhancement of 25.4%in output power as well as increment of 5%in EQE for the studied devices is observed, as the studied devices show superior current spreading ability and reduction in dislocations offered by the SL structure.

关键词： GaN superlattice(SL) current spreading hole confinement electrostatic discharge(ESD)

Estimation of Semiparametric Model with Censored Data

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Estimation of Semiparametric Model with Censored Data

Fractional Fourier domain equalization for single carrier broadband wireless systems

2010 Chinese Control and Decision Conference

作者： Chen Zhongwei and Lu Yiqiang institute of electronic technology,the PLA {3. engineering University,zhengzhou,450004

For semiparametric regression model with censored data,we firstly propose the estimators of parametric and nonparametric part by the use of kernel method based on distribution function and least squares ***,the asympt... 详细信息

关键词： semiparametric model censored data asymptotic normality strong consistency

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Science china(information Sciences) 2012年第10期55卷 2257-2268页

作者： HUANG KeWu 1,2,TAO Ran 1 & WANG Yue 1 1 Department of electronic engineering,Beijing institute of {3.,Beijing 100081,china 2 institute of Manned Space System engineering,china Academy of Space {3.,Beijing 100094,china 1. Department of electronic engineering Beijing Institute of Technology Beijing 100081 China2. Institute of Manned Space System Engineering China Academy of Space Technology Beijing 100094 China

In this paper,a novel single carrier equalization approach in the fractional Fourier domain(FRFD) is *** can remove all the inter-symbol interference(ISI) and avoid the considerable noise enhancement of the frequency domain-zero forcing(FD-ZF) *** the fractional Fourier transform makes a chirp spread,the impulse response of the deep fading channel may be flattened in some orders of the FRFD while it would be greatly attenuated in the *** searching for an optimal order under certain criterion,we take advantages of the ZF algorithm to mitigate the effects of the ISI *** approach can overcome the contradiction between the ISI mitigation and the noise enhancement of the FD-ZF *** analysis and simulation results show that the proposed FRFD-ZF equalizer can achieve a significant performance and have the same computation cost O(N log N) as the conventional FD linear equalizer,especially in the frequencyselective deep-fading channels.

关键词： fractional Fourier transform single carrier systems zero-forcing equalizer frequency domain linear equalizer

Effect of rare earths on phase transformation in as-cast ZA27 alloy dur-ing compressive creep

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Rare Metals 2003年第4期22卷 259-264页

作者： WEIXiaowei SHENBaoluo DepamnentofAppliedPhysics UniversityofElectronicScienceandTechnologyofChinaChengdu610045China DeparlanentofMetalScience SichuanUniversityChengdu610065China

The effect of the mixed rare earths of Ce on the phase transformation in ascast ZA 27 alloy during compressive was investigated under 3. MPa and at 160 deg C by X-raydiffraction technique and SEM. The results showed that the as cast microstructure of ZA 27-RE alloyconsisted of a dendritic Al-rich alpha' surrounded by Zn-rich beta' phase, interdendritic epsilonphase and Zn-rich eta phase together with a complex Z phase which was a complex constitute compound,(RE,Cu)Al_5Zn_(16), dispersed in crystal interfaces or branch crystal interfaces and stable duringcompressive creep test at 160 deg C. The phase transformations of ZA 27-RE alloy, decomposition ofbeta' phase arid four transformation, were delayed by the addition of rare earths, also the lamellarstructure and the spheroidized structure in ZA 27-RE alloy were finer than in ZA 27 alloy duringcompressive creep test at 160 deg C at the same creep time, and the compressive creep resistance ofZA 27-RE alloy was higher than that of ZA 27 alloy.

关键词： microstructure change compressive creep rare earths ZA 27 alloy

ATN-XPSL:An Access Control Policy Specification Language for Automated Trust Negotiation

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ATN-XPSL:An Access Control Policy Specification Language for...

The discrete multiple-parameter fractional Fourier transform

2006北京地区高校研究生学术交流会

作者： ZHOU Jing, ZHANG Hong-Qi, GENGYan-Jun (institute of electronic technology, {3. engineering University, zhengzhou HeNan 450004, china)

In Automated Trust Negotiation) ATN), the provider of the service or resources and the requester establish trust relationships through exchanging digitally signed credentials. The participants specify corresponding access control policies to protect the services, resources they are providing and the credentials they are holding. After analyzing the requirements of the ATN for policy specification language, an XML based policy specification language which is named ATN-XPSL is developed for the ATN. The syntax, semantic and the Basic-Policy, Combo-Policy, Chain-Policy are expatiated with instances. At last, two tools for developing the policy based on ATN-XPSL is introduced.

关键词： Automated Trast Negotiation Access Control Policy XML

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Science china(information Sciences) 2010年第11期53卷 2287-2299页

作者： LANG Jun, TAO Ran& WANG Yue Department of electronic engineering, Beijing institute of {3., Beijing 100081, china 1. Department of electronic engineering Beijing Institute of Technology Beijing 100081 China

As a generalization of the Fourier transform (FT), the fractional Fourier transform (FRFT) has many applications in the areas of optics, signal processing, information security, etc. Therefore, the efficient discrete computational method is the vital fundament for the application of the fractional Fourier transform. The multiple-parameter fractional Fourier transform (MPFRFT) is a generalized fractional Fourier transform, which not only includes FRFT as special cases, but also provides a unified framework for the study of FRFT. In this paper, we present in detail the discretization method of the MPFRFT and define the discrete multiple-parameter fractional Fourier transform (DMPFRFT). Then, we utilize the tensor product to define two-dimensional multiple-parameter fractional Fourier transform (2D-MPFRFT) and the corresponding two-dimensional discrete multiple-parameter fractional Fourier transform (2D-DMPFRFT). Finally, as an application, a novel image encryption method based on 2D-DMPFRFT is proposed. Numerical simulations are performed to demonstrate that the proposed method is reliable and more robust to blind decryption than several existing methods.

关键词： multiple-parameter fractional Fourier transform fractional Fourier transform image encryption information security

Application of asymptotic waveform approximation technique to hybrid FE/BI method for 3. scattering

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Science in china(Series F) 2007年第1期50卷 124-134页

作者： PENG Zhen1,2,3.& SHENG XinQing2 1 institute of electronics, Chinese Academy of Sciences, Beijing 100080, china 2 Department of electronic engineering, Beijing institute of technology, Beijing 100081, china 3.Graduated University of Chinese Academy of Sciences, Beijing 10003., china 1. institute of electronics Chinese Academy of Sciences Beijing 100080 China 2. Department of electronic engineering Beijing Institute of Technology Beijing 100081 China 3. Graduated University of Chinese Academy of Sciences Beijing 100039 China

The asymptotic waveform evaluation （AWE） technique is a rational function approximation method in computational mathemetics, which is used in many appllcations in computational electromagnetlca. In this paper, the performance of the AWE technique in conjunction with hybrid finite element/boundary integral （FE/BI） method is firstly Inveetlgeted. The formuletlon of the AWE applied in hybrid FE/BI method is given in detail. The characteristic implementation of the application of the AWE to the hybrid FE/BI method is discussed. Numarlcel results demonstrate that the AWE technique can greatly speed up the hybrid FE/BI method to acquire wide-band and wide-angle backecatter radar-cross-section （RCS） by complex targets.

关键词： hybrid FE/BI AWE electromagnetic scattering RCS

Detection and parameter estimation of multicomponent LFM signal based on the fractional Fourier transform

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Science in china(Series F) 2004年第2期47卷 184-198页

作者： QI Lin1, 2, TAO Ran1, ZHOU Siyong1 & WANG Yue1 1. Department of electronic engineering, Beijing institute of {3., Beijing 100081, china 2. School of information engineering, zhengzhou University, zhengzhou 450052, china Correspondence should be addressed to QI Lin (email: qilin@***) 1. Department of electronic engineering Beijing Institute of Technology 100081 Beijing China 2. School of information engineering Zhengzhou University 450052 Zhengzhou China

This paper presents a new method for the detection and parameter estimation of multicomponent LFM signals based on the fractional Fourier transform. For the optimization in the fractional Fourier domain, an algorithm based on Quasi-Newton method is proposed which consists of two steps of searching, leading to a reduction in computation without loss of accuracy. And for multicomponent signals, we further propose a signal separation technique in the fractional Fourier domain which can effectively suppress the interferences on the detection of the weak components brought by the stronger components. The statistical analysis of the estimate errors is also performed which perfects the method theoretically, and finally, simulation results are provided to show the validity of our method.

关键词： LFM signal parameter estimation fractional Fourier transform.

Influence of p-layer on the performance of n-i-p μc-Si:H thin film solar cells

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Science china(Physics,Mechanics & Astronomy) 2010年第11期53卷 2042-2046页

作者： YUAN YuJie 1,2,ZHANG KaiLiang 1,2,WEI Zhen 1,2 & GENG XinHua 3.1 College of electronics information engineering,Tianjin University of {3.,Tianjin 3.03.4,china 2 Tianjin Key Laboratory of Film electronic and Communication Devices,Tianjin University of {3.,Tianjin 3.03.4,china 3.institute of Photo-electronics Thin Film Devices and Technique,Nankai University,Tianjin 3.0071,china 1. College of electronics information engineering Tianjin University of Technology Tianjin 300384 China2. Tianjin Key Laboratory of Film Electronic and Communication Devices Tianjin University of Technology Tianjin 300384 China3. Institute of Photo-Electronics Thin Film Devices and Technique Nankai University Tianjin 300071 China

The high pressure radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) process was adopted to prepare the n-i-p microcrystalline silicon solar cells,the influence of p-type layers on the performance of the solar cells was investigated,and the optimum p layer suited to the n-i-p microcrystalline silicon solar cells was *** experimental results demonstrate that the performance of the solar cells can be highly affected by the structural and optical properties of the p-layers,and the performance of solar cells can be greatly improved by optimizing p *** have achieved an initial active-area efficiency of 8.17% (V oc =0.49 V,J sc =24.9 mA/cm 2 ,FF=67%) for the μc-Si:H single-junction n-i-p solar cells and an initial active-area efficiency of 10.93. (V oc =1.3. V,J sc =13.09 mA/cm 2 ,FF=64%) for the a-Si:H/μc-Si:H tandem n-i-p solar cells.

关键词： microcrystalline silicon solar cells quantum confinement effect p-type layers