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Terahertz radiation sources based on free electron lasers and their applications

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Science china(information Sciences) 2012年第1期55卷 1-15页

作者： TAN Ping1,HUANG Jiang2.LIU KaiFeng2.XIONG YongQian2.FAN MingWu1,2.1Department of Electronic and information engineering,Huazhong University of Science and {2.,Wuhan 43.074,china 2.4} of electrical and Electronic engineering,State Key Laboratory of Advanced Electromagnetic engineering and {2.,Huazhong University of Science and {2.,Wuhan 43.074,china 1. Department of Electronic and information engineering Huazhong University of Science and Technology Wuhan 430074 China2. College of Electrical and Electronic Engineering State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China

The tunability,high power and flexible picoseconds-pulse time structure of terahertz(THz)radiation make the THz free-electron laser(FEL)a very attractive THz source of coherent *** paper focuses on the development and perspectives of THz radiation sources based on the *** principles of the low gain THz FEL oscillator,the SASE THz FEL amplifier and the supperradiant THz FEL are reviewed briefly,and the key technologies of THz FEL,such as injector,accelerator,undulator and optical cavity,are discussed,*** current status of and future prospects for THz radiation sources based on the FEL are emphasized in this *** research and development have shown bright future in free-electron laser(FEL)THz radiation *** potential applications can be carried out in the field of imaging,material research,biology medicine,communication,diagnostics and many others.

关键词： terahertz source terahertz applications free electron laser

A New Secure Password Authentication Scheme Using Smart Cards

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Wuhan University Journal of Natural Sciences 2008年第6期13卷 739-743页

作者： WANG Bangju1,2. WANG Yuhua3. ZHANG Huanguo1 1. School of Computer, Wuhan University/Key Laboratory of Aerospace information Security and Trust Computing of Ministry of Education, Wuhan 43.072. Hubei,{3. 2. School of Science, Huazhong Agricultural University, Wuhan 43.070, Hubei,{3. 3. college of information Science and engineering, Henan University of technology Zhengzhou 450001, Henan,{3. School of information Science and technology Southwest Jiaotong University Chengdu 610031 Sichuan China

Thirteen security requirements for an ideal password authentication scheme using smart cards are listed and a new smart card based password authentication scheme with identity anonymity is proposed. The new scheme can satisfy all the listed ideal security requirements and has the following merits：（1） it can resist all the attacks listed in introduction; （2. less storage memory requirement due to no verification table stored in server; （3. low computational cost due to hash functions based operations; （4） even if the smart card is lost, the new system is still secure; （5） As user identity is anonymous, this scheme is more practical. The new proposed scheme can be applied in source constraint networks.

关键词： password password authentication hash function attack smart card

A fusion algorithm for remote sensing images based on nonsubsampled pyramids and bidimensional empirical decomposition

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Science china(Technological Sciences) 2010年第S1期53卷 196-204页

作者： ZHANG XiaoDong 1,WANG WenBo 2.WANG DiFeng 3.& ZHANG Yu 4 1 State Key Laboratory of information engineering in Surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 43.079,{2. 2.college of Sciences,Wuhan University of Science and technology,Wuhan 43.065,{2. 3.tate Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,State Oceanic Administration,Hangzhou 3.0012.{2. 4 Spatial information technology Application Research Institute,Changjiang River Scientific Research Institute,Wuhan 43.010,{2. Wuhan Univ State Key Lab Informat Engn Surveying Mapping & R Wuhan 430079 Peoples R China Wuhan Univ Sci & Technol Coll Sci Wuhan 430065 Peoples R China State Ocean Adm Inst Oceanog 2 State Key Lab Satellite Ocean Environm Dynam Hangzhou 310012 Zhejiang Peoples R China Changjiang River Sci Res Inst Spatial Informat Technol Applicat Res Inst Wuhan 430010 Peoples R China

In order to improve the quality of remote sensing image fusion,a new method combining nonsubsampled Laplacian pyramid (NLP)and bidimensional empirical mode decomposition(BEMD)is ***,the high resolution panchromatic image (PAN)is decomposed using NLP until the approximate component and the low resolution multispectral image(MS)contain features with a similar ***,the approximation component and the MS are decomposed by BEMD,resulting in a number of bidimensional intrinsic mode functions(BIMF)and a residue *** instantaneous frequency is computed in 4 directions of the *** the positive or negative coefficients in the corresponding position,a weighted algorithm is designed for fusing the high frequency details using the instantaneous frequency and the coefficient absolute value of the BIMFs as fusion *** fused image is then obtained through inverse BEMD and *** results have illustrated the advantage of this method over the IHS,DWT andà-Trous wavelet in both spectral and spatial detail qualities.

关键词： bidimensional empirical mode decomposition nonsubsampled pyramid instantaneous frequency remote sensing image fusion

Adaptive interactive genetic algorithms with individual interval fitness

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Progress in Natural Science:Materials International 2008年第3期18卷 359-365页

作者： Dunwei Gong , Guangsong Guo, Li Lu, Hongmei Ma School of information and electrical {2.,{3. University of Mining & technology, Xuzhou 2.1008,{3. School of information and electrical {2. China University of Mining & Technology Xuzhou 221008 China

It is necessary to enhance the performance of interactive genetic algorithms in order to apply them to complicated optimization prob- lems successfully. An adaptive interactive genetic algorithm with individual interval fitness is proposed in this paper in which an indi- vidual fitness is expressed by an interval. Through analyzing the fitness, information reflecting the distribution of an evolutionary population is picked up, namely, the difference of evaluating superior individuals and the difference of evaluating a population. Based on these, the adaptive probabilities of crossover and mutation operators of an individual are presented. The algorithm proposed in this paper is applied to a fashion evolutionary design system, and the results show that it can find many satisfactory solutions per generation. The achievement of the paper provides a new approach to enhance the performance of interactive genetic algorithms.

关键词： Optimization Genetic algorithm Interaction Interval Probability of genetic operator

Direct gray-scale extraction of topographic features for vein recognition

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Science china(information Sciences) 2010年第10期53卷 2062-2074页

作者： KANG WenXiong 1, LI HuaSong 2.& DENG FeiQi 1 1 college of Automation Science and engineering, South{2. University of technology, Guangzhou 510640,{2. 2.School of information engineering, Wuyi University, Jiangmen 52.000,{2. 1. college of Automation Science and engineering South China University of Technology Guangzhou 510640 China2. School of Information Engineering Wuyi University Jiangmen 529000 China

Binarization processing is a key step in most vein pattern recognition, but may create flaws such as leakage of some feature information. In order to overcome this problem, a new approach is explored in this paper which can extract topographic features directly from gray-scale vein images without binarization processing. First, an extreme graph of directional fields (EGDF) is calculated according to neighborhood information of every pixel, and then the intravenous main ridge of the image can be separated step by step from EGDF with the defined constraint template sets. After that, the sub-ridge is extracted from end points of the main ridge in range constraint image with the tracing method of maximal neighboring point. According to contrast experiment the proposed method is better than the traditional processing (performing binarization first and then skeletonization), in that it can overcome the problem that some separate vein lines are extracted incorrectly, and it can avoid extracting two neighboring vein lines as one ridge. As such, the proposed method is an effective way to extract topographic features for vein recognition

关键词： vein recognition feature extraction directional fields

Restoration method of characters on Jiagu rubbings based on Poisson distribution and fractal geometry

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Science china(information Sciences) 2010年第7期53卷 1296-1304页

作者： GU ShaoTong1,2.3. FENG GeFei1,2.3. MA XiaoHu1,2.4 & YANG YiMing1,2.3.1Institute of Linguistics, Xuzhou Normal University, Xuzhou 2.1009, china 2.iangsu college Key Lab of Linguistic Sciences and Neuro-cognition {2., Xuzhou Normal University, Xuzhou 2.1009, china 3.inguistic Science college, Xuzhou Normal University, Xuzhou 2.1009, china 4School of Computer Science and technology, Soochow University, Suzhou 2.5006, china 1. Institute of Linguistics Xuzhou Normal University Xuzhou 221009 China2. Jiangsu College Key Lab of Linguistic Sciences and Neuro-cognition Engineering Xuzhou Normal University Xuzhou 221009 China3. Linguistic Science College Xuzhou Normal University Xuzhou 221009 China4. School of Computer Science and Technology Soochow University Suzhou 215006 China

A scheme for character restoration of Jiagu rubbings based on Poisson distribution and fractal geometry is proposed in this paper. The distribution characteristics of the connected regions on Jiagu rubbings is analyzed, and all the connected regions are recognized according to differences between these and their mathematical expectations. Regions are recognized as noise regions and filled if the differences are negative, while stroke regions are reserved. The attributes of the character image edges on Jiagu rubbings are also analyzed. The fractal dimensions of the character edge of Jiagu rubbings are calculated by means of statistics. The feature points are obtained using the cosine of the angle between the two vectors of the point and the consecutive two points. Different compression transformations with weighted coordinates are performed on different strokes and segments of the characters so as to smoothen the character edge of Jiagu rubbings images. Experimental results show that our scheme could successfully clear noise regions and polish the character edge of Jiagu rubbings.

关键词： Jiagu rubbings Poisson distribution fractal geometry fractal dimension compression transformation character restoration

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,{2. 2.Department of Electronic engineering,Nation Ilan University,I-Lan 2.041,Taiwan,{2. 3.Department and Graduate Institute of Computer Science and information engineering, Chaoyang University of technology,Taichung 413.9,Taiwan,{2. [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 2. mA is decreased from 3.3.0}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 2..8%,respectively. In addition,significant enhancement of 2..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)

MMSE relay precoding schemes based on quantization error compensation for multi-relay system

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Science china(information Sciences) 2010年第12期53卷 2548-2556页

作者： LI Ting 1,2.& YANG LuXi 2.1 college of Communication and {3. {2.,Nanjing University of Posts and Telecommunications,Nanjing 2.0003.china 2.School of {3. Science and {2.,Southeast University,Nanjing 2.0096,china 1. college of Communication and information {2. Nanjing University of Posts and Telecommunications Nanjing 210003 China2. School of Information Science and Engineering Southeast University Nanjing 210096 China

In order to deal with the performance degradation resulting from the quantization error,this paper introduces the statistics of Grassmannian codebook's quantization error into relay precoding design for multirelay *** on the two-step MMSE optimization algorithm for relay precoding and receiver equalizing with full feedback under QoS requirements,we first propose a limited feedback two-step MMSE optimization scheme for relay precoding and receiver equalizing with quantization error compensation,and then we propose a limited feedback joint MMSE optimization scheme for relay precoding and receiver equalizing with quantization error compensation subject to a global power constraint at the output of *** results show that the proposed joint MMSE optimization scheme with quantization error compensation has a much lower bit-error rate than the two-step MMSE optimization scheme with quantization error compensation and the joint MMSE optimization scheme without quantization error compensation.

关键词： multi-relay precoding limited feedback minimum mean square error

electrical property of 8-mol% yttria-stabilized zirconia electrolyte by spark-plasma sintering

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Science china(Technological Sciences) 2004年第5期47卷 569-576页

作者： JIAN Jiawen1,2. CHANG Aimin3. YANG Bangchao2.& ZHANG Yikang4 1. The School of information Science {3., Ningbo University, Ningbo 3.52.1,{2. 2. The School of Microelectronics and Solid-state Electronics, University of Electronic Science and Tech-nology of{2., Chengdu 610054,{2. 3. The Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 83.02.,{2. 4. Hongtak (Chengdu) Electronic Co., Ltd, Chengdu 610041,{2. Correspondence should be addressed to Jian Jiawen 1. The School of information Science engineering Ningbo University 315211 Ningbo China 2. The School of Microelectronics and Solid-state Electronics University of Electronic Science and Technology of China 610054 Chengdu China 3. The Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of Sciences 830022 Urumqi China 4. Hongtak (Chengdu) Electronic Co. Ltd 610041 Chengdu China

Spark-plasma sintering (SPS) process was used to sinter ZrO2.(8Y) powders, and a relative density of 99% has been reached at a low temperature (13.0°C) and short dwelling time (10 min) compared to the conventional sintered identical samples (1450°C 4 h)(CS). By the X-ray diffraction (XRD) patterns, the microstructure of the SPS pellet and CS pellet are both indexed by the cubic unit cell (Fm3.). The finer crystallite size (D111) of the SPS pellet is 154 nm and D111 of the CS pellet is more than 1 μm. The AC impedance spectroscopy shows that the ionic conductivity of SPS pellet is different from that of CS pellet. The activation energy for the SPS ceramics, estimated from the slope in the range of 400–800°C, was 91 kJ mol?1, which is in good agreement with CS pellet (96 kJ mol?1), indicating that the conduction mechanism in SPS ceramics is similar to that in CS ceramics.

关键词： yttria-stabilized zirconia electrolyte, spark-plasma sintering, AC impedance.