检索结果-内蒙古大学图书馆

DYNAMICAL CHARACTER FOR A PERTURBED COUPLED NONLINEAR SCHRDINGER SYSTEM

applied mathematics and Mechanics(English Edition) 2005年第7期26卷 823-829页

作者：余沛高平郭柏灵 School of Computer and Information Chongqing Jiaotong University Chongqing 400074 P.R.China Department of Applied Mathematics Guangzhou University Guangzhou 510405 P.R.China Institute of Applied Physics and Computational Mathematics P.O.Box 8009 Beijing 100088 P.R.China

The dynamical character for a perturbed coupled nonlinear Schrodinger system with periodic boundary condition was studied. First, the dynamical character of perturbed and unperturbed systems on the invariant plane was analyzed by the spectrum of the linear operator. Then the existence of the locally invariant manifolds was proved by the singular perturbation theory and the fixed-point argument.

关键词： coupled nonlinear Schrodinger system dynamical character invariantmanifold

来源：评论

学校读者我要写书评

暂无评论

First-principles study of the interfacial adhesion between SiO2 and MoSi2

引用

Physical Review B 2005年第16期72卷 165410-165410页

作者： D. E. Jiang Emily A. Carter Department of Chemistry and Biochemistry Box 951569 University of California Los Angeles California 90095-1569 USA Department of Mechanical and Aerospace Engineering and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544-5263 USA

Upon oxidation, a silica scale forms on MoSi2, a potential high-temperature coating material for metals. This silica scale protects MoSi2 against high-temperature corrosive gases or liquids. We use periodic density functional theory to examine the interface between SiO2 and MoSi2. The interfacial bonding is localized, as evidenced by an adhesion energy that changes only slightly with the thickness of the SiO2 layer. Moreover, the adhesion energy displays a relatively large (0.40J∕m2) variation with the relative lateral position of the SiO2 and MoSi2 lattices due to changes in Si−O bonding across the interface. The most stable interfacial structure yields an ideal work of adhesion of 5.75J∕m2 within the local density approximation (5.02J∕m2 within the generalized-gradient approximation) to electron exchange and correlation, indicating extremely strong adhesion. Local densities of states and electron density difference plots demonstrate that the interfacial Si−O bonds are covalent in character. Mo−O interactions are not found in the SiO2∕MoSi2 interface investigated here. Our work predicts that the SiO2 scale strongly adheres to MoSi2, and further supports the potential of MoSi2 as a high-temperature structural material and coating.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Fluid permeabilities of triply periodic minimal surfaces

引用

Physical Review E 2005年第5期72卷 056319-056319页

作者： Y. Jung S. Torquato Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

It has recently been shown that triply periodic two-phase bicontinuous composites with interfaces that are the Schwartz primitive (P) and diamond (D) minimal surfaces are not only geometrically extremal but extremal for simultaneous transport of heat and electricity. The multifunctionality of such two-phase systems has been further established by demonstrating that they are also extremal when a competition is set up between the effective bulk modulus and electrical (or thermal) conductivity of the bicontinuous composite. Here we compute the fluid permeabilities of these and other triply periodic bicontinuous structures at a porosity ϕ=1∕2 using the immersed-boundary finite-volume method. The other triply periodic porous media that we study include the Schoen gyroid (G) minimal surface, two different pore-channel models, and an array of spherical obstacles arranged on the sites of a simple cubic lattice. We find that the Schwartz P porous medium has the largest fluid permeability among all of the six triply periodic porous media considered in this paper. The fluid permeabilities are shown to be inversely proportional to the corresponding specific surfaces for these structures. This leads to the conjecture that the maximal fluid permeability for a triply periodic porous medium with a simply connected pore space at a porosity ϕ=1∕2 is achieved by the structure that globally minimizes the specific surface.

关键词： EXACT COMPUTATION FLOW SIMULATIONS COMPOSITES TRANSPORT SYSTEMS PHASES STEP

来源：评论

学校读者我要写书评

暂无评论

Interplay of single-wall carbon nanotubes and encapsulated La@C82, La2@C80, and Sc3N@C80

引用

Physical Review B 2005年第23期71卷 235417-235417页

作者： Jing Lu Shigeru Nagase Suyong Re Xinwei Zhang Dapeng Yu Jin Zhang Rushan Han Zhengxiang Gao Hengqiang Ye Shuang Zhang Lianmao Peng Department of Physics Mesoscopic Physics Laboratory Peking University Beijing 100871 People’s Republic of China Department of Theoretical Studies Institute for Molecular Science Okazaki 444-8585 Japan Institute of Applied Physics and Computational Mathematics Beijing 100088 People’s Republic of China Department of Electronics Peking University Beijing 100871 People’s Republic of China

Encapsulations of metallofullerenes (La@C82, La2@C80, and Sc3N@C80) inside single-wall carbon nanotubes are investigated by using first-principles calculations. We found that La@C82, La2@C80, and Sc3N@C80 are endothermically encapsulated inside the (17,0) nanotube, while the encapsulation processes are exothermic inside the (14,7) and (19,0) nanotubes. Electron transfer takes place from the nanotubes to strongly electrophilic La@C82 and La2@C80. Dependent on the tube chirality, the Van Hove singularity positions of the nanotube may be significantly shifted by a local 3% radial strain induced by metallofullerene insertion.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Parallel adaptive quantum trajectory method for wavepacket simulations

Parallel adaptive quantum trajectory method for wavepacket s...

引用

作者： Cariño, Ricolindo L. Banicescu, Ioana Vadapalli, Ravi K. Weatherford, Charles A. Zhu, Jianping Center for Computational Sciences Engineering Research Center Mississippi State University PO Box 9627 Mississippi State MS 39762 United States Department of Physics Florida Agricultural and Mechanical University Tallahassee FL 52507 United States Department of Theoretical and Applied Mathematics University of Akron Akron OH 44325-4002 United States Department of Computer Science Mississippi State University PO Box 9637 Mississippi State MS 39762 United States

Time-dependent wavepackets are widely used to model various phenomena in physics. One approach in simulating the wavepacket dynamics is the quantum trajectory method (QTM). Based on the hydrodynamic formulation of quantum mechanics, the QTM represents the wavepacket by an unstructured set of pseudoparticles whose trajectories are coupled by the quantum potential. The governing equations for the pseudoparticle trajectories are solved using a computationally-intensive moving weighted least squares (MWLS) algorithm, and the trajectories can be computed in parallel. This paper contributes a strategy for improving the performance of wavepacket simulations using the QTM. Specifically, adaptivity is incorporated into the MWLS algorithm, and loop scheduling techniques are employed to dynamically load balance the parallel computation of the trajectories. The adaptive MWLS algorithm reduces the amount of computations without sacrificing accuracy, while adaptive loop scheduling addresses the load imbalance introduced by the algorithm and the runtime system. Results of experiments on a Linux cluster are presented to confirm that the adaptive MWLS reduces the trajectory computation time by up to 24%, and adaptive loop scheduling achieves parallel efficiencies of up to 85% when simulating a free particle. © World Scientific Publishing Company.

关键词： Parallel processing systems

来源：评论

学校读者我要写书评

暂无评论

Systematic identification of statistically significant network measures

引用

Physical Review E 2005年第1期71卷 016110-016110页

作者： Etay Ziv Robin Koytcheff Manuel Middendorf Chris Wiggins College of Physicians and Surgeons Columbia University New York New York 10027 USA Department of Biomedical Engineering Columbia University New York New York 10027 USA Department of Applied Physics and Applied Mathematics Columbia University New York New York 10027 USA Department of Physics Columbia University New York New York 10027 USA Center for Computational Biology and Bioinformatics Columbia University New York New York 10027 USA

We present a graph embedding space (i.e., a set of measures on graphs) for performing statistical analyses of networks. Key improvements over existing approaches include discovery of “motif hubs” (multiple overlapping significant subgraphs), computational efficiency relative to subgraph census, and flexibility (the method is easily generalizable to weighted and signed graphs). The embedding space is based on scalars, functionals of the adjacency matrix representing the network. Scalars are global, involving all nodes; although they can be related to subgraph enumeration, there is not a one-to-one mapping between scalars and subgraphs. Improvements in network randomization and significance testing—we learn the distribution rather than assuming Gaussianity—are also presented. The resulting algorithm establishes a systematic approach to the identification of the most significant scalars and suggests machine-learning techniques for network classification.

关键词： ESCHERICHIA-COLI TRANSCRIPTIONAL REGULATION COMPLEX NETWORKS PROTEIN ORGANIZATION SPECIFICITY GRAPHS MOTIFS OPERON

来源：评论

学校读者我要写书评

暂无评论

Geometric Phase for Adiabatic Evolutions of General Quantum States

引用

Physical Review Letters 2005年第14期94卷 140402-140402页

作者： Biao Wu Jie Liu Qian Niu Institute of Physics Chinese Academy of Sciences P.O. Box 603 Beijing 100080 China Condensed Matter Sciences Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing 100088 China Department of Physics The University of Texas at Austin Austin Texas 78712 USA

The concept of a geometric phase (Berry’s phase) is generalized to the case of noneigenstates, which is applicable to both linear and nonlinear quantum systems. This is particularly important to nonlinear quantum systems, where, due to the lack of the superposition principle, the adiabatic evolution of a general state cannot be described in terms of eigenstates. For linear quantum systems, our new geometric phase reduces to a statistical average of Berry’s phases. Our results are demonstrated with a nonlinear two-level model.

关键词： .Geometric phase adiabatic evolution Berry phases control parameters general quantum nonlinear quantum geometric part noneigenstates

来源：评论

学校读者我要写书评

暂无评论

Pump-probe scheme for optical coherence tomography using indocyanine green mixed with albumin or human plasma

Pump-probe scheme for optical coherence tomography using ind...

引用

Conference on Lasers and Electro-Optics (CLEO)

作者： Z. Yaqoob J.P. Fingler S. Lintner B.E. Applegate Changhuei Yang Electrical Engineering California Institute of Technology Pasadena CA USA Applied Physics California Institute of Technology Pasadena CA USA Applied & Computational Mathematics California Institute of Technology Pasadena CA USA Department of Biomedical Engineering Duke University Durham NC USA

Use of indocyanine green (ICG) in a pump-probe scheme for OCT is proposed. The study illustrates that ICG in protein solution shows unusual pump-probe imaging potential, indicating its usefulness as a contrast agent f... 详细信息

ISBN: (纸本)1557527954

关键词： Optical pumping Tomography Humans Plasmas Biomedical optical imaging High-resolution imaging Absorption Optical imaging Laser beams Pump lasers

来源：评论

学校读者我要写书评

暂无评论

Vector solitons with an embedded domain wall

引用

Physical Review E 2005年第6期72卷 066604-066604页

作者： P. G. Kevrekidis H. Susanto R. Carretero-González B. A. Malomed D. J. Frantzeskakis Department of Mathematics and Statistics University of Massachusetts Amherst Massachusetts 01003-4515 USA Department of Applied Mathematics University of Twente P.O. Box 217 7500 AE Enschede The Netherlands Nonlinear Dynamical Systems Group Department of Mathematics and Statistics and Computational Science Research Center San Diego State University San Diego California 92182-7720 USA Department of Interdisciplinary Studies Faculty of Engineering Tel Aviv University Tel Aviv 69978 Israel Department of Physics University of Athens Panepistimiopolis Zografos Athens 15784 Greece

We present a class of soliton solutions to a system of two coupled nonlinear Schrödinger equations, with an intrinsic domain wall (DW) which separates regions occupied by two different fields. The model describes a binary mixture of two Bose-Einstein condensates (BECs) with interspecies repulsion. For the attractive or repulsive interactions inside each species, we find solutions which are bright or dark solitons in each component, while for the opposite signs of the intraspecies interaction, a bright-dark soliton pair is found (each time, with the intrinsic DW). These solutions can arise in the context of discrete lattices, and most of them can be supported in continuum settings by an external parabolic trap. The stability of the solitons with intrinsic DWs is examined, and the evolution of unstable ones is analyzed. We also briefly discuss the possibility of generating such families of solutions in the presence of linear coupling between the components, and an application of the model to bimodal light propagation in nonlinear optics.

关键词： BOSE-EINSTEIN CONDENSATE COLLECTIVE EXCITATIONS FESHBACH RESONANCES ELASTIC-SCATTERING OPTICAL LATTICES BINARY-MIXTURES DARK SOLITONS MATTER-WAVES GASES DYNAMICS

来源：评论

学校读者我要写书评

暂无评论

Fidelity for the quantum evolution of a Bose-Einstein condensate

引用

Physical Review A 2005年第6期72卷 063623-063623页

作者： Jie Liu Wenge Wang Chuanwei Zhang Qian Niu Baowen Li Department of Physics and the Beijing–Hong Kong–Singapore Joint Center for Nonlinear and Complex Systems (Singapore) National University of Singapore 117542 Republic of Singapore Institute of Applied Physics and Computational Mathematics P.O. Box 100088 Beijing People’s Republic of China Department of Physics Southeast University Nanjing 210096 People’s Republic of China Department of Physics The University of Texas Austin Texas 78712-1081 USA Center for Nonlinear Dynamics The University of Texas Austin Texas 78712-1081 USA Graduate School for Integrative Sciences and Engineering National University of Singapore 117597 Republic of Singapore

We investigate fidelity for the quantum evolution of a Bose-Einstein condensate (BEC) and reveal its general property with a simple two-component BEC model. We find that, when the initial state is a coherent state, the fidelity decays with time in the ways of exponential, Gaussian, and power law, depending on the initial location, the perturbation strength, as well as the underlying mean-field classical dynamics. In this case we find a clear correspondence between the fast quantum fidelity decay and the dynamical instability of the mean-field system. With the initial state prepared as a maximally entangled state, we find that the behavior of fidelity has no classical correspondence and observe an interesting behavior of the fidelity: periodic revival, where the period is inversely proportional to the number of bosons and the perturbation strength. An experimental observation of the fidelity decay is suggested.

关键词： CHAOTIC SYSTEMS DECOHERENCE GAS

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：