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作者： Ling Xu Fei Yang Yuanbao Liao Wenqiang Liu Dong Liu Jun Xu Zhongyuan Ma and Kunji Chen National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and electronic Materials sciences and technology school of physics and school of electronic science and technology Nanjing University Nanjing 210093 People’s Republic of China

Ternary alloy, Ge2Sb2Te5, Ge1Sb2Te4 are two kinds of compounds along the GeTe-Sb2Te3 pseudobinary line. They are found to have good optical and electrical contrast between the amorphous and crystalline states and, and have featuring characteristics for phase change memory. In this study, the sputtering method is used to prepare Ge2Sb2Te5 and Ge1Sb2Te4 thin films. The band gaps of GST thin films are determined from the measured absorption spectra. With the help of Tauc equation,the estimated optical band gaps of the amorphous, fcc and hexagonal Ge2Sb2Te5 thin films are 0.8, 0.7 and 0.65 eV, respectively. The estimated band gaps of the amorphous, fcc and hexagonal Ge1Sb2Te4 thin films are 0.5 eV, 0.4 and 0.3 eV, which are smaller than that of amorphous. The results of the temperature dependence of the sheet resistance upon a heating rate show that both Ge2Sb2Te5 and Ge1Sb2Te4 thin film exhibit a temperature-activated electrical conductivity. We also measure the carrier mobility μ using surface acoustic wave technology, which is an appropriate method for materials with low conductivities. Typical mobilities for Ge2Sb2Te5 and Ge1Sb2Te4 thin films of about 0.001-1 cm2/Vs and 1-10 cm2/Vs in the temperature range of 300-480 K were found at amorphous and crystalline states respectively. Transport via the hopping among localized states （both from band tail of the valence band and structural vacancies such as localized Tellurium lone pairs） were thought to dominate the temperature between 20-80 C.

关键词： Ge2Sb2Te5 and Ge1Sb2Te4 phase-change materials electronic band structure Electrical transport properties

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Dynamic behavior of micro-diaphragms and its characterized description

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science China(physics,Mechanics & Astronomy) 2009年第8期52卷 1345-1356页

作者： GE LiFeng school of electronic science and technology, Anhui University, Hefei 230039, China school of electronic science and technology Anhui University Hefei China

Diaphragm structures with micron scale play a significant role in microtransducers and micro-nano devices, and the performance of these devices depends mainly on the dynamic behaviour of diaphragms. Micro-diaphragms are treated commonly as membranes and in some cases as plates or plates in tension (called TD plates for short), but they also show in many cases the behaviour of plates in tension and supported by air spring (called TDK plates for short). Therefore, it is necessary to perform systematic research on the dynamic behaviour of micro-diaphragms, and establish a characterized mathematical description. This paper focuses on the TDK plates since they possess universality, gives the corresponding basic equations, and then derives analytical solutions of TDK circular plates under clamped and simply supported boundary conditions. This paper also gives a 3D plot representation of characteristic curved surfaces, revealing the transition from the TDK and TD plate to the pure plate or pure membrane behaviour; and further uses the value φ to determine the property of diaphragms. Its two extreme cases, i.e. φ = 0 and φ = ∞ , correspond to pure plate or pure membrane, respectively. Thus, membrane, plate and TD plate can be treated as special cases of TDK plate. In addition, this paper reveals that the presence of air-spring not only enhances the restoring force of diaphragm such that increases its natural frequencies, but also results in the resonance of a dynamic system consisting of diaphragm and air-spring. These analytical and computational results are significant for the understanding of the operation mechanism of capacitive microtransducers and their optimized design.

关键词： micro-diaphragm membrane and plate TD plate and TDK plate dynamic behaviour characterized description

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Study of the starting pressure gradient in branching network

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science China(Technological sciences) 2010年第4期53卷 2397-2403页

作者： LI Yan & YU BoMing school of physics,Huazhong University of science and technology,Wuahn 430074,China school of physics Huazhong University of Science and Technology

In order to increase the production of oil in low permeability reservoirs with high efficiency,it is necessary to fully understand the properties and special behaviors of the reservoirs and correctly describe the flow in the *** paper applies the branching network mode to the study of the starting pressure gradient of nonlinear Newtonian fluid (Bingham fluid) in the reservoirs with low permeability based on the fact that the fractured network may exist in the *** proposed model for starting pressure gradient is a function of yield stress,microstructural parameters of the *** proposed model may have the potential in further exploiting the mechanisms of flow in porous media with fractured network.

关键词： Bingham fluid flow branching network starting pressure gradient

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C^MC^N D-computable state

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science China(physics,Mechanics & Astronomy) 2008年第9期51卷 1300-1307页

作者： LIU DongDong1,2 & DI YaoMin1 1 school of physics & electronic Engineering,Xuzhou Normal University,Xuzhou 221116,China 2 school of Mathematics & physics science,Xuzhou Institute of technology,Xuzhou 221008,China school of physics & electronic Engineering Xuzhou Normal University Xuzhou China school of Mathematics & physics science Xuzhou Institute of Technology Xuzhou China

The notions of D-computable state and D-concurrence are generalized to the CMCN system. A class of D-computable state on CMCN is given and the calculating method of the lower bound of D-concurrence is provided. Th... 详细信息

关键词： quantum entanglement entanglement of formation concurrence D-computable state

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The analyticity of solutions to a class of degenerate elliptic equations

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science China Mathematics 2010年第8期53卷 2061-2068页

作者： LI ChunHe school of Mathematical science,University of electronic science and technology of China,Chengdu 610054,China school of Mathematical science University of Electronic Science and Technology of China Chengdu China

In the present paper,the analyticity of solutions to a class of degenerate elliptic equations is obtained.A kind of weighted norms are introduced and under such norms some degenerate elliptic operators are of weak coe... 详细信息

关键词： analyticity degenerate elliptic equations weighted norm weak coerciveness

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Special Orientation Relationships Observed at the Early Stages of Recrystallization in Pure AlMn Alloy

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International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 140-146页

作者： Ping Yang(Material science and Engineering school, University of science and technology Beijing, Beijing 100083, China)(Institute for Metal science and Metal physics, Aachen University of technology, D-52056, Aachen, Germany) Material science and Engineering school University of Science and Technology Beijing Beijing 100083 China Institute for Metal science and Metal physics Aachen University of Technology D-52056 Aachen Germany

Electron Back Scattering Diffraction (EBSD) technique in a SEM was used to obtain local orientationalinformation on new grains and their surrounding deformed matrices at the early stages of recrystallization in pureA1-1 .3%Mn alloy. Results show that special orientation relationships including twin-relationship often exist betweennew grains, between new grains and deformed grains or between deformed grains. The occurrence of such specialorientation relationships is attributed to the special deformation behavior in the samples with large initial grain *** formation of recrystallization twins is discussed in a different way to those of traditional ones.

关键词： Orientation relationship recrystallization AlMn, EBSD

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A regularization method in the electromagnetic inverse scattering problem

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Progress in Natural science:Materials International 2007年第3期17卷 346-351页

作者： XIONG Xiaoyun, ZHAO Yanwen and NIE Zaiping (school of electronic Engineering, University of electronic science and technology of China, Chengdu 610054, China) school of electronic Engineering University of Electronic Science and Technology of China Chengdu 610054 China

Based on the normalization of measurement data equations of the inverse scattering problem, a new regularization matrix is proposed. It can eliminate the unfavorable effects caused by difference of distances between field-point or source-point and target region, reduce the loss of useful information in regularization procedure, and decrease condition numbers of the ill-posed problems. Inversion for conductivity distribution of two-dimensional axisymmetric inhomogeneous media is carried out by combing this new regularization method with distorted Born iterative method. Simulation results show that compared with the conventional method, the new regularization method is of better stability, quicker convergence, higher accuracy of inversion and higher resolution.

关键词： inverse scattering regularization distorted Born iterative method.

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Exploring non-equilibrium statistical ensembles

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science Bulletin 2011年第34期56卷 3654-3660页

作者： BI Qiao & LIU Jie Department of physics, school of science, Wuhan University of technology, Wuhan 430070, China Department of physics School of Science Wuhan University of Technology Wuhan China

Since Gibbs synthesized a general equilibrium statistical ensemble theory, generalizing the Gibbsian theory to non-equilibrium phenomena has been a dream for some theorists. However, the status of the theory for the non-equilibrium ensemble formalism is not as well established as the Gibbsian ensemble theory. In this work, we explore the formalism behind the non-equilibrium statistical ensemble theory based on the sub-dynamic kinetic equation originating from the Brussels-Austin school and developed further by others. The key is establishing a similarity transformation between Gibbsian ensembles and the sub-dynamic ensemble. Using this way, we study a spin-Boson model with strong coupling. A reduced density operator for the canonical ensemble can be easily obtained and the relevant decoherence-free property is revealed.

关键词： subdynamics statistical ensemble non-equilibrium statistical physics

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Hybrid of comprehensive learning particle swarm optimization and SQP algorithm for large scale economic load dispatch optimization of power system

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science China(Information sciences) 2010年第8期53卷 1566-1573页

作者： WANG Yu , LI Bin & YUAN Bo Department of electronic science and technology, school of Information science and technology, University of science and technology of China, Hefei 230027, China Department of electronic science and technology School of Information Science and Technology University of Science and Technology of China Hefei China

Economic load dispatch (ELD) is an important optimization task in power systems. In the previous works, various researchers attempted to address this problem by both mathmatical and heuristic optimization algorithms. However, there are still two practically important issues that have not attracted sufficient attention: 1) the stability of these algorithms cannot be effectively ensured; 2) the performance of these algorithms on large scale ELD optimization tasks remains to be unsatisfactory. CLPSO is an effective global optimization algorithm. To strengthen the convergence ability of CLPSO, the sequential quadratic programming (SQP) is introduced into it. This results in a new algorithm hybrid of comprehensive learning particle swarm optimization and sequential quadratic programming (SQP-CLPSO). To assess the performance of SQP-CLPSO, it is compared with several state-of-the-art evolutionary algorithms (EAs) on the classical ELD optimization problems. Experimental results show that SQP-CLPSO has very good abilities of convergence, diversity maintainence and scalability, which make it suitable for complex ELD problems.

关键词： particle swarm optimization comprehensive learning particle swarm optimization sequential quadratic programming local search power systems economic load dispatch

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An improved model of Robinson equivalent circuit analytical model

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science China(Technological sciences) 2010年第7期53卷 1993-1999页

作者： MAO XiangYu & DU PingAn school of Mechatronics Engineering, University of electronic science and technology of China, Chengdu 611731, China school of Mechatronics Engineering University of Electronic Science and Technology of China Chengdu China

The Robinson equivalent circuit analytical model can be used only in calculating shielding effectiveness of enclosure with the same multi-holes in one wall, but cannot be used in different multi-holes in two walls. According to the practical requirement, this article uses Konefal's and Farhana's characteristic impedance of apertures to improve the equivalent circuit analytical model in different multi-holes in two walls. The improved equivalent circuit analytical model is more useful than Robinson equivalent circuit analytical model. In the article, all kinds of enclosures are simulated by TLM (Transmission-Line Matrix method) to prove that this improved model is feasible in multimode.

关键词： equivalent circuit improved model apertures shielding effectiveness TLM (Transmission-Line Matrix method)

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