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A NOTE ON THE DIPERNA-LIONS FLOWS

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Acta Mathematica Scientia 2011年第5期31卷 1719-1724页

作者：刘昕黄文亮 School of Computer science and technology Huazhong University of Science and Technology department of Mathematics East China University of Science and Technology

In this note, we give a short proof for the DiPerna-Lions flows associated to ODEs following the method of Crippa and De Lellis [3]. More precisely, assume that [divb] ∈ Ll∞oc（Rd）, ｜b｜/（1 ＋｜x｜ log ｜x｜） ∈ L∞（Rd） and ｜ b｜ φ（｜ b｜） ∈ Ll1oc（Rd）, where φ（r） = log log（r ＋ c）, c 0. Then, there exists a unique regular Lagrangian flow associated with the ODE X˙（t, x） = b（X（t, x））, X（0, x） = x.

关键词： DiPerna-Lions flow Hardy-Littlewood maximal function

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On degrees of freedom of the cellular network

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science china(Information sciences) 2010年第05期53卷 1034-1043页

作者： SUN Jun 1,2 , LIU YingZhuang 1,2 & ZHU GuangXi 1,2 1 department of Electronics and Information Engineering, huazhong university of science and technology, wuhan 430074, china 2 Division of Optical Network and Intelligent Communication, wuhan National Laboratory for Optoelectronics, wuhan 430074, china 1. department of Electronics and Information Engineering Huazhong University of Science and Technology Wuhan 430074 China2. Division of Optical Network and Intelligent Communication Wuhan National Laboratory for Optoelectronics Wuhan 430074 China

In this paper, we consider the capacity limits of the cellular network by modeling it as consisting of two mutually interfering multiple access channels with multiple antennas at each receiver (e.g., base station). By developing a tight outerbound as well as an achievable scheme which exploits the idea of interference alignment, we are able to exactly characterize the sum degrees of freedom (DoF) of the network when the channel coefficients are timeor frequency-varying, which equals KM K+min(M,K) (where M and K denote the number of receiver antennas and number of users in per cell, respectively) per cell. From the DoF result, it can be observed that in addition to the multi-user gain which has been reported for the network with single-antenna BSs, there also exists the multi-antenna gain in the cellular network. In particular, when the number of users is large, we can nearly achieve the interference-free DoF of a cellular network with multiple-antenna BSs, which is a somewhat surprising result.

关键词： capacity degrees of freedom cellular network interference alignment interference channel MIMO

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 technology,wuhan 430074,china 2College of Electrical and Electronic Engineering,State Key Laboratory of Advanced Electromagnetic Engineering and technology,huazhong university of science and technology,wuhan 430074,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

Particle swarm optimization algorithm for partner selection in virtual enterprise

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Progress in Natural science:Materials International 2008年第11期18卷 1445-1452页

作者： Qiang Zhao~a Xinhui Zhang~(b,*) Renbin Xiao~c a School of Mechanical science and Engineering,huazhong university of science and technology,wuhan 430074,china b department of Biomedical,Industrial & Human Factors Engineering,Wright State university,Dayton,OH 45435,USA c Institute of Systems Engineering,huazhong university of science and technology,wuhan 430074,china School of Mechanical science and Engineering Huazhong University of Science and Technology Wuhan 430074 China department of Biomedical Industrial & Human Factors Engineering Wright State University Dayton OH 45435 USA Institute of Systems Engineering Huazhong University of Science and Technology Wuhan 430074 China

Partner selection is a fundamental problem in the formation and success of a virtual *** partner selection problem with precedence and due date constraint is the basis of the various extensions and is studied in this paper.A nonlinear integer program model for the partner selection problem is *** problem is shown to be NP-complete by reduction to the knapsack problem,and therefore no polynomial time algorithm *** solve it efficiently,a particle swarm optimization(PSO)algorithm is adopted,and several mechanisms that include initialization expansion mechanism,variance mechanism and local searching mechanism have been developed to improve the performance of the proposed PSO algorithm.A set of experiments have been conducted using real examples and numerical simulation,and have shown that the PSO algorithm is an effective and efficient way to solve the partner selection problems with precedence and due date constraints.

关键词： Virtual enterprise Partner selection PSO NP-complete

Ferroelectric properties of Bi_(3.4)Ho_(0.6)Ti_3O_(12) thin films prepared by sol-gel method

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science china(Technological sciences) 2008年第9期51卷 1439-1444页

作者： FU ChengJu1, HUANG ZhiXiong1, LI Jie2 & GUO DongYun3 1 School of Materials science and technology, wuhan university of technology, wuhan 430070, china 2 School of Mechanical Engineering, Chongqing university of science and technology, Chongqing 400050, china 3 department of physics, wuhan university, wuhan 430072, china School of Materials science and technology Wuhan University of Technology Wuhan 430070 China School of Mechanical Engineering Chongqing University of Science and Technology Chongqing 400050 China department of physics Wuhan University Wuhan 430072 China

We have prepared the Ho-substituted bismuth titanate (Bi3.4Ho0.6Ti3O12, BHT) thin films on Pt/Ti/SiO2/Si substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure. The 2Pr and 2Ec of the 600-nm-thick BHT film were 38.4 μC/cm2 and 376.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 310 and 0.015 at a frequency of 1 MHz, respectively. The Pr value decreased to 93% of its pre-fatigue values after 4.46×109 switching cycles at 1 MHz frenquency, and the BHT film shows good in-sulating behavior according to the test of leakage current.

关键词： Bi3.4Ho0.6Ti3O12 thin film sol-gel method ferroelectric property fatigue dielectric constant

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STOCHASTIC HEAT EQUATIONS WITH RANDOM INITIAL CONDITIONS

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Chinese Annals of Mathematics 2005年第4期 112-123页

作者： ZHANG XICHENG department of Mathematics, huazhong university of science and technology, wuhan 430074, china.

In this paper the author constructs a solution of parabolic stochastic partial differential equation with random initial conditions by Kolmogorov’s criterion.

关键词： Stochastic partial differential equation Green’s function Kolmogorov’s criterion

ANALYSIS OF SOUND RADIATION FROM THE RING-STIFFENED CYLINDRICAL SHELL COATED WITH VISCOELASTIC LAYER IN FLUID MEDIUM

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Acta Mechanica Solida Sinica 2003年第2期16卷 155-161页

作者： Luo Dongping Cai Minbo Peng Xu Luo Bin (department of Naval and Ocean Engineering,huazhong university of science and technology,wuhan 430074,china) department of Naval Engineering Huazhong Univ. of Sci./Technology Wuhan 430074 China

The Donnell theory of shell is applied to describe shell motion and layer motion is described by means of three-dimensional Navier *** deformation harmonious condi- tions of the interface,the effects of stiffeners and layer are treated as reverse forces and moments acting on the cylindrical *** studying the acoustic field produced by vibration of the sub- merged ring-stiffened cylindrical coated shell,the structure dynamic equation,Helmholtz equation in the fluid field and the continuous conditions of the fluid-structure interface compose the cou- pling vibration equation of the *** extract of sound pressure comes down to the extract of coupling vibration *** use of the solution of the equation,the influ- ences of hydrostatic pressure,physical characters and geometric parameters of the layer on sound radiation are discussed.

关键词： viscoelastic layer ring-stiffened cylindrical coated shell coupling vibration equation sound radiation

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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

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

Investigation on Self-Q-Switched Er3+-Doped Fiber Lasers

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Chinese Journal of Lasers 1995年第3期B4卷 211-216页

作者： SUN Junqiang HUANG Dexiu(department of Optoelectronic Engineeringhuazhong university of science and technology, wuhan 430074, china)LI Zaiguang(National Laboratory of Laser technology, wuhan 430074, china) huazhong Univ of science and Technology Wuhan China

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关键词： changeable nonlinear refraction index self-Q-switching