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Basin filling algorithm for the circular packing problem with equilibrium behavioral constraints

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science china({2. sciences) 2010年第5期53卷 885-895页

作者： LIU JingFa1& LI Gang2.1school of Computer and Software, nanjing {2. of information science & technology, nanjing 2.0044, china 2.0} of mathematics and physics, nanjing {2. of information science & technology, nanjing 2.0044, china 1. school of Computer and Software Nanjing University of Information Science & Technology Nanjing 210044 China2. School of Mathematics and Physics Nanjing University of Information Science & Technology Nanjing 210044 China

With the background of the satellite module layout design, the circular packing problem with equilibrium behavioral constraints is a layout optimization problem and NP-hard problem in math. For lack of a powerful optimization method, this problem is hard to solve. The energy landscape paving (ELP) method is a class of stochastic global optimization algorithms based on the Monte Carlo sampling. Based on the quasiphysical strategy and the penalty function method, the problem is converted into an unconstrained optimization problem. Here by combining the improved ELP method, the gradient method based on local search and the heuristic configuration update mechanism, a new global search algorithm, basin filling algorithm, is put forward. The numerical results show that the proposed algorithm is effective to solving the circular packing problem with equilibrium behavioral constraints, and is easy to be popularized to other layout optimization problems.

关键词： equilibrium behavioral constraints packing problem layout optimization

Characteristics of fMRI BOLD signal and its neurophysiological mechanism

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Progress in Natural science:Materials International 2007年第6期17卷 630-638页

作者： Zhao Xiaohu1,2. Wu Yigen3 and Guo Shengli3(1. College of Life sciences, Zhejiang university, Hangzhou 310058, {2. 2. Imaging Department of Tongji Hospital of Tongji university, Shanghai 2.0065, {2. 3. College of mathematics and physics, nanjing university of information science and technology, {12., {2.) College of Life sciences Zhejiang University Hangzhou 310058 China Imaging Department Tongji Hospital Tongji University Shanghai 200065 China College of mathematics and physics Nanjing University of Information Science and Technology Nanjing 210044 China

The functional magnetic resonance imaging (fMRI) based on blood oxygen level dependent (BOLD) contrast has emerged as one of the most potent noninvasive tools for mapping brain function and has been widely used to explore physiological, pathological changes and mental activity in the brain. Exploring the nature and property of BOLD signal has recently attracted more attentions. Despite that great progress has been made in investigation of the characteristics and neurophysiological basis, the exact nature of BOLD signal remains unclear. In this paper we discuss the characteristics of BOLD signals, the nonlinear BOLD response to external stimuli and the relation between BOLD signals and neural electrophysiological recordings. Furthermore, we develop our new opinions regarding nonlinear BOLD response and make some perspectives on future study.

关键词： functional magnetic resonance imaging blood oxygen level dependent nonlinear response neural electrophysiological activity.

Two possible mechanisms for vortex self-organization

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science china Earth sciences 2006年第2期49卷 202-211页

作者： LUO Zhexian2. ZHOU Xiuji1 & GAO Shouting3 1. Chinese Academy of Meteorological sciences, Beijing 100081, china 2. Department of Space {2. science, nanjing university of {2. science and technology, nanjing 2.0044, china 3. Institute of Atmospheric physics, Chinese Academy of sciences, Beijing 10002., china 2. Department of Environmental science Nanjing University of Information Science and Technology Nanjing 210044 China 1. Chinese Academy of Meteorological sciences Beijing 100081 China 3. Institute of Atmospheric physics Chinese Academy of Sciences Beijing 100029 China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.

A relative local variational principle for topological pressure

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science china {2. 2010年第6期53卷 1491-1506页

作者： MA XianFeng1,CHEN ErCai2.3,& ZHANG AiHua2.4 1Department of mathematics,East china {2. of science and technology,Shanghai 2.02.7,china 2.6} of mathematics and Computer science,nanjing Normal {2.,nanjing 2.0097,china 3Center of Nonlinear science,nanjing {2.,nanjing 2.0093,china 4College of mathematics and physics,nanjing {2. of Posts and Telecommunications,nanjing 2.0046,china 1. Department of mathematics East China University of Science and Technology Shanghai 200237 China2. School of Mathematics and Computer Science Nanjing Normal University Nanjing 210097 China3. Center of Nonlinear Science Nanjing University Nanjing 210093 China4. College of Mathematics and Physics Nanjing University of Posts and Telecommunications Nanjing 210046 China

We define the relative local topological pressure for any given factor map and open cover,and prove the relative local variational principle of this *** precisely,for a given factor map π:(X,T)→(Y,S) between two topological dynamical systems,an open cover U of X,a continuous,real-valued function f on X and an S-invariant measure ν on Y,we show that the corresponding relative local pressure P(T,f,U,y) satisfies sup μ∈M(X,T){ hμ(T,U|Y)+∫X f(x)dμ(x) :πμ=ν}=∫Y P(T,f,U,y)dν(y),where M(X,T) denotes the family of all T-invariant measures on ***,the supremum can be attained by a T-invariant measure.

关键词： pressure conditional entropy relative local variational principle

Travelling wave solutions of a generalized Camassa-Holm-Degasperis-Procesi equation

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science china {2. 2011年第3期54卷 555-572页

作者： DENG ShengFu1, GUO BoLing2.& WANG TingChun2.3 1Department of mathematics, Zhanjiang Normal university, Zhanjiang 52.048, {2. 2.nstitute of Applied physics and Computational mathematics, Beijing 100088, {2. 3 College of Math and physics, nanjing university of information science and technology, {12., {2. 1. Department of mathematics Zhanjiang Normal University Zhanjiang 524048 China2. Institute of Applied Physics and Computational Mathematics Beijing 100088 China3. College of Math and Physics Nanjing University of Information Science and Technology Nanjing 210044 China

The travelling wave solutions of a generalized Camassa-Holm-Degasperis-Procesi equation ut-uxxt + (1 + b)umux = buxuxx + uuxxx are considered where b > 1 and m are positive integers. The qualitative analysis methods of planar autonomous systems yield its phase portraits. Its soliton wave solutions, kink or antikink wave solutions, peakon wave solutions, compacton wave solutions, periodic wave solutions and periodic cusp wave solutions are obtained. Some numerical simulations of these solutions are also given.

关键词： homoclinic orbits heteroclinic orbits peakon wave solutions compacton wave solutions periodic cusp wave solutions

A study of two-dimensional magnetic polaron

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science china({2.,Mechanics & Astronomy) 2006年第4期49卷 421-429页

作者： LIU Tao1, ZHANG Huaihong1, FENG Mang1,2.& WANG Kelin1,3 1. school of science, Southwest {2. of science and technology, Mianyang 62.010, china 2. Wuhan Institute of physics and mathematics, Chinese Academy of sciences, Wuhan 430070, china 3. Department of Modern physics, {2. of science and technology of china, Hefei 2.002., china school of science Southwest University of Science technology Mianyang 621010 China Wuhan Institute of physics mathematics Chinese Academy of Sciences Wuhan 430070 China Department of Modern physics University of Science technology of china Hefei 230026 China

By using the variational method and anneal simulation, we study in this paper the self-trapped magnetic polaron (STMP) in two-dimensional anti-ferromagnetic material and the bound magnetic polaron (BMP) in ferromagnetic material. Schwinger angular momentum theory is applied to changing the problem into a coupling problem of carriers and two types of Bosons. Our calculation shows that there are single-peak and multi-peak structures in the two-dimensional STMP. For the ferromagnetic material, the properties of the two-dimensional BMP are almost the same as that in one-dimensional case; but for the anti-ferromagnetic material, the two-dimensional STMP structure is much richer than the one-dimensional case.

关键词： self-trapped magnetic polaron, bound magnetic polaron, impurity potential, anti-ferromagnet.

Bell violation for the thermal states of an XXZ spin chain with Dzialoshiski-Moriya interaction

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science china({2.,Mechanics & Astronomy) 2010年第11期53卷 2074-2079页

作者： MA XiaoSan 1 & WANG AnMin 2.1 school of Electric Engineering and information,Anhui {2. of technology,Maanshan 2.3002.china 2.Department of Modern physics,{2. of science and technology of china,Hefei 2.002.,china 1. school of Electric Engineering and information Anhui University of Technology Maanshan 243002 China2. Department of Modern Physics University of Science and Technology of China Hefei 230026 China

The effect of Dzialoshiski-Moriya (DM) interaction on the violation of Bell inequality for thermal states of interacting qubits via a two-qubit XXZ spin chain is *** results imply that the DM interaction and anisotropy taking a large positive value can enhance the Bell violation and improve the threshold temperatures of *** the comparison between the Bell violation and thermal entanglement,we find that the threshold temperatures of thermal entanglement are higher than those of the Bell *** implies that some states are entangled but the Bell inequality is not violated.

关键词： Bell violation threshold temperatures DM interaction

A computational investigation of boron-doped chromium and chromium clusters by density functional theory

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science china({2.,Mechanics & Astronomy) 2010年第5期53卷 812-817页

作者： GE GuiXian1,JING Qun1 & LUO YouHua2.3 1 Key Laboratory of Ecophysics and Department of physics,Normal College,Shihezi {2.,Xinjiang 832.03,china 2.school of science,East china {2. of science and technology,Shanghai 2.02.7,china 3 Institute of Theoretical physics,school of physics and information Optoelectronics,Henan {2.,Kaifeng 475004,china 1. Key Laboratory of Ecophysics and Department of physics Normal College Shihezi University Xinjiang 832003 China2. School of Science East China University of Science and Technology Shanghai 200237 China3. Institute of Theoretical Physics School of Physics and Information Optoelectronics Henan University Kaifeng 475004 China

The geometries,stabilities and electronic properties of Crn and CrnB(n=2.9) clusters have been systematically investigated by density functional *** results suggest that the lowest energy structures for CrnB clusters can be obtained by substituting one Cr atom in Crn+1 clusters with B *** geometries of CrnB clusters are similar to that of Crn+1 clusters except for local structural *** second-order difference and fragmentation energy show Cr4,Cr6,Cr8,Cr3B,Cr5B and Cr8B cluster are the most stable among these studied *** impurity B increases the stabilities of chromium *** B is doped on the Crn clusters,cluster geometry does dominate positive role in enhancing their *** doped B atom does not change the coupling way of the Cr site in Crn clusters,but breaks the symmetry and the Cr atoms are no longer *** doped B atom increases the total magnetic moments of Crn in most cases.

关键词： Crn and CrnB clusters geometries electronic properties

Numerical simulation of Meiyu front and the diagnosis of moist vorticity vector

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Progress in Natural science:Materials International 2007年第11期17卷 1341-1347页

作者： Ping Fan1,2.and Luo Zhexian2.1. Institute of Atmospheric physics, Chinese Academy of sciences, Beijing 10002., {2. 2. nanjing university of information sciences & technology, nanjing 2.0044, {2.) Institute of Atmospheric physics Chinese Academy of Sciences Beijing 100029 China nanjing university of {2. sciences & technology Nanjing 210044 China

Moist vorticity vector is introduced to study the development and evolution of mesoscale convective vortex (MCV) in the Meiyu front precipitation with the Advanced Regional Predication System (ARPS). In this study, the heavy rainfall is simulated to investigate the genesis, development and dissipation of middle scale convective vortex, which occurred from 0000 UTC 3 July to 12.0 UTC 5 July over the Jianghuai River valley. Moist vorticity vector (MVV) has zonal, radial and vertical components in its 3D spatial distribution. The simulation shows that the vertical component of moist vorticity vector well demonstrates the spatial distribution characteristics of middle scale convective vortex, especially in the process of Meiyu front precipitation. Diagnosis upon zonal, radial averaged and mass-integrated quantities of MVV shows that its vertical component and the surface precipitating ratio are in phase with a correlation coefficient of 0.68, indicating that the vertical component of MVV is closely associated with the Meiyu front precipitation. In addition, the tendency of the vertical component of MVV is mainly determined by the interaction between the vorticity and the zonal and radial gradient of condensational or depositional heating.

关键词： moist vorticity vector mesoscale convective vortex Meiyu front precipitation