检索结果-内蒙古大学图书馆

Simulation of Hydrogen Emission Spectrum in Debye Plasmas

Chinese physics Letters 2011年第5期28卷 84-87页

作者： DING Qi-Yong ZHANG Song-Bin WANG Jian-Guo The Key Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsP.O.Box 8009Beijing 100088 Graduate School of China Academy of Engineering Physics P.O.Box 2101Beijing 100088 Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics University of Science and Technology of ChinaHefei 230026

We investigate the screening effects on the spectrum of spontaneous radiation and radiative recombination to the 1s,2s and 2p states of hydrogen with total atom density N=1.7×10^(19)cm^(-3)and electron temperatures 1eV,2eV and 5eV under the local thermodynamic equilibrium(LTE)*** needed atomic energy levels,the radiative transition probabilities and radiative recombination cross sections are calculated by solving the Schr(o)dinger equation numerically incorporating the Debye-Hückel model in *** plasma emission spectrum is simulated for the first time by using the screened atomic *** red shift and the cutoff of Rydberg spectra are observed and it is also found that the 2 eV electron temperature case has the strongest screening effects and the emission spectra to the 2s and 2p states are more likely affected by screening effects than that of the ls state.

关键词： Debye radiative spectrum

来源：评论

学校读者我要写书评

暂无评论

Optimized pulses for the control of uncertain qubits

引用

Physical Review A 2012年第5期85卷 052313-052313页

作者： Matthew D. Grace Jason M. Dominy Wayne M. Witzel Malcolm S. Carroll Department of Scalable and Secure Systems Research Sandia National Laboratories Livermore CA 94550 United States Program in Applied and Computational Mathematics Princeton University Princeton NJ 08544 United States Department of Advanced Device Technologies Sandia National Laboratories Albuquerque NM 87185 United States Department of Photonic Microsystem Technologies Sandia National Laboratories Albuquerque NM 87185 United States Center for Quantum Information Science and Technology University of Southern California Los Angeles CA 90089 United States

Constructing high-fidelity control fields that are robust to control, system, and/or surrounding environment uncertainties is a crucial objective for quantum information processing. Using the two-state Landau-Zener model for illustrative simulations of a controlled qubit, we generate optimal controls for π/2 and π pulses and investigate their inherent robustness to uncertainty in the magnitude of the drift Hamiltonian. Next, we construct a quantum-control protocol to improve system-drift robustness by combining environment-decoupling pulse criteria and optimal control theory for unitary operations. By perturbatively expanding the unitary time-evolution operator for an open quantum system, previous analysis of environment-decoupling control pulses has calculated explicit control-field criteria to suppress environment-induced errors up to (but not including) third order from π/2 and π pulses. We systematically integrate this criteria with optimal control theory, incorporating an estimate of the uncertain parameter to produce improvements in gate fidelity and robustness, demonstrated via a numerical example based on double quantum dot qubits. For the qubit model used in this work, postfacto analysis of the resulting controls suggests that realistic control-field fluctuations and noise may contribute just as significantly to gate errors as system and environment fluctuations.

关键词： Quantum optics

来源：评论

学校读者我要写书评

暂无评论

Nonlinear Geometric Effects in Mechanical Bistable Morphing Structures

引用

Physical Review Letters 2012年第11期109卷 114302-114302页

作者： Zi Chen Qiaohang Guo Carmel Majidi Wenzhe Chen David J. Srolovitz Mikko P. Haataja Department of Mechanical and Aerospace Engineering Princeton University Princeton New Jersey 08544 USA Princeton Institute for the Science and Technology of Materials (PRISM) Princeton University Princeton New Jersey 08544 USA Department of Biomedical Engineering Washington University St. Louis Missouri 63130 USA College of Materials Science and Engineering Fuzhou University Fuzhou Fujian 350108 China Department of Mathematics and Physics Fujian University of Technology Fuzhou Fujian 350108 China Department of Mechanical Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213 USA Department of Materials Science and Engineering Fujian University of Technology Fuzhou Fujian 350108 China Institute for High Performance Computing 1 Fusionopolis Way Singapore 138632 Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA School of Mathematics Institute for Advanced Study Princeton New Jersey 08540 USA

Bistable structures associated with nonlinear deformation behavior, exemplified by the Venus flytrap and slap bracelet, can switch between different functional shapes upon actuation. Despite numerous efforts in modeling such large deformation behavior of shells, the roles of mechanical and nonlinear geometric effects on bistability remain elusive. We demonstrate, through both theoretical analysis and tabletop experiments, that two dimensionless parameters control bistability. Our work classifies the conditions for bistability, and extends the large deformation theory of plates and shells.

关键词： Deformation

来源：评论

学校读者我要写书评

暂无评论

Building Chessboard-like Nanoporous suprastructures at Surface

Building Chessboard-like Nanoporous suprastructures at Surfa...

引用

中国物理学会2012年秋季学术会议

作者： Ruifen Dou Yu Yang Ping Zhang Dingyong Zhong Harald Fuchs Yue Wang Lifen Department of Physics Beijing Normal University Beijing 100875 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China Physikalishes Institut Westf(a)lische Wihlms-Universit(a)t Münster Wilhelm-klemm-Str. 10 48149 Münster Germany Key Laboratory for Supramolecular Structure and Materials of the Ministry of Education College of Chemistry Jilin University Chang Chun 130012 China

investigate an anthracene derivative,3(5)-(9-anthryl) pyrazole (ANP),a light-emitting,nonplanar molecule,self-assembling on a Au (111) surface by means of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations.A chessboard-like porous networks composed of ANP molecules is found on the Au (111) surface.

关键词： Self-Assembly of Monolayers (SAMs) Porous Networks Au(111) Scanning Tunneling Microscopy (STM) Density functional theory (DFT)

来源：评论

学校读者我要写书评

暂无评论

Optimal Filling of Shapes

引用

Physical Review Letters 2012年第19期108卷 198304-198304页

作者： Carolyn L. Phillips Joshua A. Anderson Greg Huber Sharon C. Glotzer Applied Physics Program University of Michigan Ann Arbor Michigan 48109 USA Department of Chemical Engineering University of Michigan Ann Arbor Michigan 48109 USA Center for Cell Analysis and Modeling University of Connecticut Health Center Farmington Connecticut 06032 USA Department of Cell Biology University of Connecticut Health Center Farmington Connecticut 06032 USA Department of Mathematics University of Connecticut Storrs Connecticut 06032 USA Department of Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA

We present filling as a type of spatial subdivision problem similar to covering and packing. Filling addresses the optimal placement of overlapping objects lying entirely inside an arbitrary shape so as to cover the most interior volume. In n-dimensional space, if the objects are polydisperse n-balls, we show that solutions correspond to sets of maximal n-balls. For polygons, we provide a heuristic for finding solutions of maximal disks. We consider the properties of ideal distributions of N disks as N→∞. We note an analogy with energy landscapes.

关键词： Filling

来源：评论

学校读者我要写书评

暂无评论

Effective Maxwell Equations from Time-dependent Density Functional Theory

引用

Acta Mathematica Sinica,English Series 2011年第2期27卷 339-368页

作者： Weinan E Jianfeng LU Xu YANG Department of Mathematics and Program in Applied and Computational Mathematics Princeton University Princeton NJ 08544 USA Beijing International Center for Mathematical Research and School of Mathematical Sciences Peking University Beijing 100871 P. R. China Department of Mathematics Courant Institute of Mathematical Sciences New York University New York NY 10012 USA

The behavior of interacting electrons in a perfect crystal under macroscopic external electric and magnetic fields is studied. Effective Maxwell equations for the macroscopic electric and magnetic fields are derived starting from time-dependent density functional theory. Effective permittivity and permeability coefficients are obtained.

关键词： Time-dependent density functional theory Maxwell equations effective permittivity electromagnetic fields

来源：评论

学校读者我要写书评

暂无评论

Dynamics of a Single Spin-1/2 Coupled to x - and y -Spin Baths: Algorithm and Results

引用

physics Procedia 2012年 34卷 90-99页

作者： M.A. Novotny Marta L. Guerra Hans De Raedt Kristel Michielsen Fengping Jin Department of Physics and Astronomy and HPC2 Center for Computational Sciences Mississippi State University P.O. Box 5167 Mississippi State MS 39762-5167 USA Institute for Advanced Simulation J’ulich Supercomputing Centre Forschungszentrum J’ulich D-52425 J’ulich Germany Department of Sciences & Mathematics Mississippi University for Women 1100 College Street MUW-100 Columbus MS 39701 USA Department of Applied Physics Zernike Institute for Advanced Materials University of Groningen Nijenborgh 4 NL-9747 AG Groningen The Netherlands RWTH Aachen University D-52056 Aachen Germany

The real-time dynamics of a single spin-1/2 particle, called the central spin, coupled to the x ( y )-components of the spins of one or more baths is simulated. The bath Hamiltonians contain interactions of x ( y )-components of the bath spins only but are general otherwise. An efficient algorithm is described which allows solving the time-dependent Schr’odinger equation for the central spin, even if the x ( y ) baths contain hundreds of spins. The algorithm requires storage for 2 × 2 matrices only, no matter how many spins are in the baths. We calculate the expectation value of the central spin, as well as its von Neumann entropy S( t ), the quantum purity P( t ), and the off-diagonal elements of the quantum density matrix. In the case of coupling the central spin to both x - and y - baths the relaxation of S( t ) and P( t ) with time is a power law, compared to an exponential if the central spin is only coupled to an x -bath. The effect of different initial states for the central spin and bath is studied. Comparison with more general spin baths is also presented.

关键词： Quantum Dynamics Spin Bath Decoherence Thermalization

来源：评论

学校读者我要写书评

暂无评论

Electron-Ion Collision Studies with Highly Charged Sulfur Ions

引用

Journal of physics: Conference Series 2012年第6期388卷

作者： S Ali S Mahmood I Orban S Tashenov Y M Li Z Wu R Schuch Department of Physics Stockholm University Albanova University Center 106 91 Stockholm Sweden Institute of Applied Physics and Computational Mathematics 100088 Beijing People's Republic of China

We have obtained dielectronic recombination (DR) cross sections for H-like and He-like S, using the Stockholm Refrigerated Electron Beam Ion Trap (R-EBIT). The experimental results are compared with a calculation for the resonance positions and strengths and show good agreement within the error bars, but also deviations in some cases.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Taxonomies of networks from community structure

引用

Physical Review E 2012年第3期86卷 036104-036104页

作者： Jukka-Pekka Onnela Daniel J. Fenn Stephen Reid Mason A. Porter Peter J. Mucha Mark D. Fricker Nick S. Jones Department of Biostatistics Harvard School of Public Health Boston Massachusetts 02115 USA Department of Health Care Policy Harvard Medical School Boston Massachusetts 02115 USA Department of Physics University of Oxford Oxford OX1 3PU United Kingdom CABDyN Complexity Centre University of Oxford Oxford OX1 1HP United Kingdom Mathematical and Computational Finance Group University of Oxford Oxford OX1 3LB United Kingdom Oxford Centre for Industrial and Applied Mathematics Mathematical Institute University of Oxford OX1 3LB United Kingdom Carolina Center for Interdisciplinary Applied Mathematics Department of Mathematics and Institute for Advanced Materials Nanoscience & Technology University of North Carolina Chapel Hill North Carolina 27599 USA Department of Plant Sciences University of Oxford South Parks Road Oxford OX1 3RB United Kingdom Oxford Centre for Integrative Systems Biology Department of Biochemistry University of Oxford Oxford OX1 3QU United Kingdom Department of Mathematics Imperial College London SW7 2AZ United Kingdom

The study of networks has become a substantial interdisciplinary endeavor that encompasses myriad disciplines in the natural, social, and information sciences. Here we introduce a framework for constructing taxonomies of networks based on their structural similarities. These networks can arise from any of numerous sources: They can be empirical or synthetic, they can arise from multiple realizations of a single process (either empirical or synthetic), they can represent entirely different systems in different disciplines, etc. Because mesoscopic properties of networks are hypothesized to be important for network function, we base our comparisons on summaries of network community structures. Although we use a specific method for uncovering network communities, much of the introduced framework is independent of that choice. After introducing the framework, we apply it to construct a taxonomy for 746 networks and demonstrate that our approach usefully identifies similar networks. We also construct taxonomies within individual categories of networks, and we thereby expose nontrivial structure. For example, we create taxonomies for similarity networks constructed from both political voting data and financial data. We also construct network taxonomies to compare the social structures of 100 Facebook networks and the growth structures produced by different types of fungi.

关键词： Taxonomies

来源：评论

学校读者我要写书评

暂无评论

Second-order time evolution scheme for time-dependent neutron transport equation

Second-order time evolution scheme for time-dependent neutro...

引用

作者： Hong, Zhenying Yuan, Guangwei Fu, Xuedong Yang, Shulin Institute of Applied Physics and Computational Mathematics Department 6 NO.2. Fenghaodong Road Haidian District Beijing 100094 China

In this paper, the typical exponential method, diamond difference and modified time discrete scheme is researched for self adaptive time step. The second-order time evolution scheme is applied to time-dependent spherical neutron transport equation by discrete ordinates method. The numerical results show that second-order time evolution scheme associated exponential method has some good properties. The time differential curve about neutron current is more smooth than that of exponential method and diamond difference and modified time discrete scheme.

关键词： Diamonds

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：