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Science china(physics,Mechanics & Astronomy) 2010年第5期53卷 856-863页

作者： CAI Xin1,2,LIU JinSong1 & WANG ShengLie1 1 wuhan National Laboratory for Optoelectronics,School of Optoelectronic Science and Engineering,Huazhong university of Science and technology,wuhan 43.074,china 2 School of Science,wuhan university of technology,wuhan 43.070,china wuhan National Laboratory for Optoelectronics School of Optoelectronic Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

The transverse effects of two Gauss waves mixing in a photovoltaic photorefractive crystal,i.e.,the dynamical evolutions of signal beam with different parameters,are traced numerically and *** the one-dimensional numerical simulations and two-dimensional experimental investigations show that the self-focusing effect of signal beam becomes more obvious as the intensity of pump beam and the angle between the signal and pump beams *** accordance with these results,the state of two Gaussian waves mixing is controllable.

关键词： numerical simulation experimental investigation two-wave mixing transverse effects Gaussian distribution

Preparation and Structural Characterization of Polystyrene-Rectorite Nanocomposites

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wuhan university Journal of Natural Sciences 2003年第3A期8卷 817-820页

作者： Fang Peng\|fei, Liu Li\|ming, Zhang Ming, Zhang Shao\|ping, Wang Bo, Wang Shao\|jie School of physics and technology, wuhan university, {3. 430072. Hubei,china School of physics and technology Wuhan University Wuhan Hubei China

The polystyrene/rectorite nanocomposites were prepared by free radical polymerization of styrene containing dispersed organophilic rectorite. The structures and thermal properties of these hybrids have been investigated by X\|ray diffraction (XRD), fourier transform infrared (FT\|IR), positron annihilation spectroscopy (PAS) and thermal gravimetric analysis (TGA) techniques. It was found that exfoliation of rectorite in polystyrene (PS) matrix was achieved. The average free\|volume radius in the PS/clay nanocomposites is generally same as that in PS. Along with increment of rectorite contents, the interface between rectorite and polystyrene matrix increases, and the free\|volume concentration decreases obviously. And the polystyrene nanocomposites have higher thermal decomposition temperature than pure PS.

关键词： polystyrene rectorite nanocomposites positron annihilation spectroscopy

SULFATE RESISTANCE MECHANISM OF HIGH- PERFORMANCE CONCRETE CONTAINING NCI

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Journal of wuhan university of technology(Materials Science) 1999年第1期14卷 6-15页

作者： MA Baoguo wuhan university of technology wuhan university of technology China Coll. of Mat. Sci. and Engineering Wuhan University of Technology Wuhan 430070 China

It is found that the incorporation of Nitrite Corrosion Inhibitor (NCI) greatly weakens the resistance of mixtures to sulfate attack. To study the mechanism of this phenomenon, in this paper, the influence of NCI addition on the cement paste and microstructure change of high performance concrete specimens is studied by means of quantitative XRD, SEM tests. The results demonstrate that the incorporation of NCI accelerates the formation of calcium hydroxide and ettringite crystals, and weakens the pore refinement effect caused by the secondary hydration reaction of fly ash and microsilica. At the age up to one year, the relative crystal quantity in mixture containing NCI is always higher than that in control mixture. The reasons for the degradation in sulfate resistance of mixtures may be attributed to the increase and stability of the calcium hydroxide and ettringite crystals formed and the weakening of secondary hydration reaction. Based on the results, conclusion can be drawn that NCI should be used cautiously in practical engineering where high resistance to sulfate attack is required. (Author abstract) 7 Refs.

关键词： nitrite corrosion inhibitor high-performance concrete microstructure sulfate resistance

Development of Mathematical Model on Preparation of Functionally Graded Material by Co-sedimentation

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Journal of Materials Science & technology 2001年第2期17卷 275-277页

作者： Zhongmin YANG, Lianmeng ZHANG and Qiang SHEN Institute of Materials Science and Engineering, wuhan university of technology, wuhan 43.070, {3. Inst. of Mat. Sci. Wuhan Univ. of Technol. Wuhan 430070 China

From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.

关键词： Co Mo Development of Mathematical Model on Preparation of Functionally Graded Material by Co-sedimentation

Frequency Synthesizer of Short-Wave SFH/MFSK System

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wuhan university Journal of Natural Sciences 1998年第1期3卷 71-75页

作者： Gan Liangcai, Bao Yongqiang(college of Electronic Information, Wuha university, wuhan 430072. china) Wuha university College of Electronic Information Wuhan China

The technology of DDS-driven PLL is introduced and a new scheme of frequency synthesizer which is suitable for SW SFH/MFSK System is presented in this paper. Based on the special requirement of SW communication, a model of the scheme is given and the results show that the frequency synthesizer has small frequency insteval (≤0.1 Hz), short switch pierod (<200 ms) and high frequency stability as crystal oseillator.

关键词： Key words frequency synthesizer frequency inteval switch pierod FH communication

Microstructures and fatigue-free properties of the La^(3.) and Nd^(3.) doped Bi_4Ti_3._(12) thin films prepared by modified sol-gel technique

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Science china(Technological Sciences) 2008年第11期51卷 1843-1849页

作者： LI MeiYa1,2, PEI Ling1, LIU Jun1, YU BenFang1, GUO DongYun1, SUN XiaoHua3.& ZHAO XingZhong1,2 1 Department of Electronic Science and technology, School of Physical Science and technology, wuhan university,{3. 2 Key Laboratory of Acoustic and Photonic Material and Device of the Ministry of Education, wuhan Uni- versity,{3. 3.School of Mechanical and Material Engineering, china Three Gorges university, Yichang 443.02, china Department of Electronic Science and technology School of Physical Science and Technology

Ferroelectric Bi3.25La0.75Ti3.12 (BLT) and Bi3.15Nd0.85Ti3.12 (BNT) thin films were fab- ricated on Pt/TiO2/SiO2/Si (100) substrates by a modified sol-gel technique. X-ray diffraction indicated that these films were of single phase with random polycrystal- line orientations. The surface morphologies of the films were observed by scanning electron microscope, showing uniform, dense films with grain size of 50―100 nm. Well-saturated hysteresis loops of the films were obtained in metal-ferroelectric- metal type capacitors with Cu top electrodes at an applied voltage of 400 kV/cm, giving the remanent polarization (2Pr) and coercive field (2Ec) values of the films of 25.1 μC/cm2 and 203.kV/cm for BLT, and 44.2 μC/cm2 and 296 kV/cm for BNT, re- spectively. Moreover, these capacitors did not show fatigue behaviors after up to 1.75×1010 switching cycles at the test frequency of 1 MHz, suggesting a fatigue-free character. The influences of the La3. and Nd3. doping on the properties of the films were comparatively discussed.

关键词： bismuth oxides ferroelectrics fatigue sol-gel technique

Mathematical stencil and its application in finite difference approximation to the Poisson equation

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Science china Mathematics 2005年第10期48卷 1421-1429页

作者： FENG Hui~1 ZHANG Baolin~(1,2) & LIU Yang~1 1. Department of Mathematics,wuhan university,wuhan {3.china 2. Laboratory of Computational physics,Institute of Applied physics and Computational Mathematics,Beijing 100088. china Department of Mathematics Wuhan University Wuhan China Laboratory of Computational physics Institute of Applied Physics and Computational Mathematics Beijing China

The concept of mathematical stencil and the strategy of stencil elimination for solving the finite difference equation is presented, and then a new type of the iteration algorithm is established for the Poisson equation. The new algorithm has not only the obvious property of parallelism, but also faster convergence rate than that of the classical Jacobi iteration. Numerical experiments show that the time for the new algorithm is less than that of Jacobi and Gauss-Seidel methods to obtain the same precision, and the computational velocity increases obviously when the new iterative method, instead of Jacobi method, is applied to polish operation in multi-grid method, furthermore, the polynomial acceleration method is still applicable to the new iterative method.

关键词： mathematical stencil, stencil elimination, Poisson equation, finite difference, iterative algorithm,parallelism.

Tele-Network Design Based on Queue Competition Algorithm

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wuhan university Journal of Natural Sciences 2003年第S1期8卷 327-330页

作者： Huang Zhang-can, Wan Li-jun, Tang Tao, Chen Zheng-xuState Key Laboratory of Software Engineering, wuhan university, wuhan 430072. Hubei, {3.School of Material Science and Engineering, wuhan university of technology , wuhan 43.070, Hubei, {3.School of Automation, wuhan university of technology, wuhan 43.070, Hubei, {3.School of Science, wuhan university of technology, wuhan 43.070, Hubei, {3. State Key Laboratory of Software Engineering Wuhan University Wuhan Hubei China School of Material Science and Engineering Wuhan University of Technology Wuhan Hubei China School of Automation Wuhan University of Technology Wuhan Hubei China School of Science Wuhan University of Technology Wuhan Hubei China

In this paper, we report research on how to design the tele-network. First of all, we defined the reliability of tele-network. According to the definition, we divide the whole reliability into two parts:the reliability of the mini-way and that of the whole system. Then we do algebra unintersection of the mini-way, deriving a function of reliability of tele-network. Also, we got a function of the cost of tele-network after analyzing the cost of arcs and points. Finally, we give a mathematical model to design a tele-network. For the algorithm, we define the distance of a network and adjacent area within certain boundaries . We present a new algorithm--Queue Competition Algorithm (QCA) based on the adjacent area . The QCA correlates sequence of fitnesses in their father-generations with hunting zone of mutation and the number of individuals generated by mutation, making the stronger fitness in a small zone converge at a local extreme value, but the weaker one takes the advantage of lots of individuals and a big zone to hunt a new local extreme value. In this way, we get the overall extreme value. Numerical simulation shows that we can get the efficient hunting and exact solution by using QCA. The QCA efficient hunting and exact solution.

关键词： reliability Queue Competition algorithm the distance of a network adjacent area

Modeling Digital Video Database System with UML

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wuhan university Journal of Natural Sciences 2001年第Z1期6卷 234-238页

作者： Yu Jun qing, Zhou Dong ru, Jin Ye, Xu Jun college of Computer Science and technology, wuhan university,{3. college of Computer Science and technology Wuhan University Wuhan 430072 China

The main purpose of the model is to present how the Unified Modeling Language (UML) can be used for modeling digital video database system (VDBS). It demonstrates the modeling process that can be followed during the analysis phase of complex applications. In order to guarantee the continuity mapping of the models, the authors propose some suggestions to transform the use case diagrams into an object diagram, which is one of the main diagrams for the next development phases.

关键词： UML video database class object sequence

D-Dimensional Dirac Fermions BEC-BCS Crossover Thermodynamics

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Communications in Theoretical physics 2007年第7期48卷 99-106页

作者： CHEN Ji-Sheng Institute of Particle physics & physics Department,Central china Normal {3.,wuhan 43.079,china Institute of Particle physics Central China Normal University physics Department Central China Normal University

An effective relativistic continuum massive Proca Lagrangian action is used to account for the Lorentzvector condensation effects on the equation of state of the strongly interacting fermions *** interior quantumfluctuation effects are incorporated as an external field approximation indirectly through a fictive generalized ThomsonProblem counterterm *** general analytical formulas for the d-dimensional thermodynamics are given nearthe unitary limit region,In the non-relativistic limit for d=3.the universal dimensionless coefficientε=4/9 andenergy gap △/ε_f=5/18 are reasonably consistent with the existing theoretical and experimental *** the unitarylimit for d=2 and T=0,the universal coefficient can even approach the extreme occasion ξ=0 corresponding to theinfinite effective fermion mass m~*=∞,which can be mapped to the strongly coupled two-dimensional electrons and isquite similar to the three-dimensional Bose-Einstein condensation of ideal boson ***,for d=1,the universalcoefficient ξ is negative,implying the non-existence of phase transition from superfluidity to normal *** solutionsmanifest the quantum Ising universal class characteristic of the strongly coupled unitary fermions gas.

关键词： unitary fermions thermodynamics BEC-BCS crossover statistical methods