检索结果-内蒙古大学图书馆

作者： Huang, Yunqing Li, Jichun Yang, Wei Hunan Key Laboratory for Computation and Simulation in Science Engineering Xiangtan University Hunan 411105 China Department of Mathematical Sciences University of Nevada Las Vegas Las Vegas NV 89154-4020 United States

We investigate the well-posedness of a perfectly matched layer model developed by Cohen and Monk [Comput Methods Appl Mech Eng 169 (1999), 197-217]. A new time-domain finite element method is proposed to solve the model. A novel feature of the scheme is that the number of unknowns is reduced to two from four in the original form. The scheme's effectiveness is demonstrated through numerical experiments. © 2013 Wiley Periodicals, Inc.

关键词： Maxwell equations

来源：评论

学校读者我要写书评

暂无评论

Two classes of implicit–explicit multistep methods for nonlinear stiff initial-value problems

引用

Applied Mathematics and Computation 2014年 247卷 47-60页

作者： Aiguo Xiao Gengen Zhang Xing Yi School of Mathematics and Computational Science Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan Hunan 411105 China

The initial value problems of nonlinear ordinary differential equations which contain stiff and nonstiff terms often arise from many applications. In order to reduce the computation cost, implicit–explicit (IMEX) methods are often applied to these problems, i.e. the stiff and non-stiff terms are discretized by using implicit and explicit methods, respectively. In this paper, we mainly consider the nonlinear stiff initial-value problems satisfying the one-sided Lipschitz condition and a class of singularly perturbed initial-value problems, and present two classes of the IMEX multistep methods by combining implicit one-leg methods with explicit linear multistep methods and explicit one-leg methods, respectively. The order conditions and the convergence results of these methods are obtained. Some efficient methods are constructed. Some numerical examples are given to verify the validity of the obtained theoretical results.

关键词： Stiff problems Singular perturbation problems Implicit–explicit multistep methods One-leg methods Linear multistep methods Convergence

来源：评论

学校读者我要写书评

暂无评论

Time-splitting finite difference method with the wavelet-adaptive grids for semiclassical Gross–Pitaevskii equation in supercritical case

引用

Journal of Computational Physics 2014年 267卷 146-161页

作者： Xueyang Li Aiguo Xiao School of Mathematics and Computational Science Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan Hunan 411105 PR China

The Gross–Pitaevskii equation is the model equation of the single-particle wave function in a Bose–Einstein condensation. A computation difficulty of the Gross–Pitaevskii equation comes from the semiclassical problem in supercritical case. In this paper, we apply a diffeomorphism to transform the original one-dimensional Gross–Pitaevskii equation into a modified equation. The adaptive grids are constructed through the interpolating wavelet method. Then, we use the time-splitting finite difference method with the wavelet-adaptive grids to solve the modified Gross–Pitaevskii equation, where the approximation to the second-order derivative is given by the Lagrange interpolation method. At last, the numerical results are given. It is shown that the obtained time-splitting finite difference method with the wavelet-adaptive grids is very efficient for solving the one-dimensional semiclassical Gross–Pitaevskii equation in supercritical case and it is suitable to deal with the local high oscillation of the solution.

关键词： Gross–Pitaevskii equation Wavelet-adaptive grids Time-splitting finite difference method Interpolating wavelet Lagrange interpolation method

来源：评论

学校读者我要写书评

暂无评论

Highly regioselective 1,3-dipolar cycloaddition of diphenylnitrilimine to Sc₃N@I_h-C₈₀ affording a very stable, unprecedented pyrazole-ring fused derivative of endohedral metallofullerenes

引用

Chemical Communications 2014年第84期50卷 12710-12713页

作者： Liu, Bin Cong, Hailin Li, Xiaofang Yu, Bing Bao, Lipiao Cai, Wenting Xie, Yunpeng Lu, Xing Key Laboratory of Theoretical Chemistry and Molecular Simulation Ministry of Education Hunan Province College Key Laboratory of QSAR/QSPR School of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan 411201 China Lab for New Fiber Materials and Modern Textile-Growing Base State Key Laboratory College of Chemical and Environmental Engineering Qingdao University Qingdao 266071 China State Key Laboratory of Materials Processing and Die and Mold Technology School of Materials Science and Engineering Huazhong University of Science and Technology (HUST) Wuhan 430074 China

Formation of a very stable, unprecedented pyrazole-ring fused derivative of endohedral metallofullerenes was achieved by the first 1,3-dipolar cycloaddition reaction of Sc3N@C80 with diphenylnitrilimine in a highly re... 详细信息

关键词： METALLOFULLERENES RESEARCH PYRAZOLES REGIOSELECTIVITY (Chemistry) RING formation (Chemistry) HIGH performance liquid chromatography MASS spectrometry

来源：评论

学校读者我要写书评

暂无评论

Underlying scaling relationships between solar activity and geomagnetic activity revealed by multifractal analyses

引用

Journal of Geophysical Research: Space Physics 2014年第9期119卷 7577-7586页

作者： Yu, Zu-Guo Anh, Vo Eastes, Richard Hunan Key Laboratory for Computation and Simulation in Science and Engineering Ministry of Education Xiangtan University Xiangtan Hunan China School of Mathematical Sciences Queensland University of Technology Brisbane QLD Australia Florida Space Institute University of Central Florida Orlando FL United States

This paper identifies some scaling relationships between solar activity and geomagnetic activity. We examine the scaling properties of hourly data for two geomagnetic indices (a_p and AE), two solar indices (solar X-rays X_l and solar flux F10.7), and two inner heliospheric indices (ion density Ni and flow speed Vs) over the period 1995-2001 by the universal multifractal approach and the traditional multifractal analysis. We found that the universal multifractal model (UMM) provides a good fit to the empirical K(q) and τ(q) curves of these time series. The estimated values of the Lévy index α in the UMM indicate that multifractality exists in the time series for a_p, AE, X_l, and Ni, while those for F10.7 and Vs are monofractal. The estimated values of the nonconservation parameter H of this model confirm that these time series are conservative which indicate that the mean value of the process is constant for varying resolution. Additionally, the multifractal K(q) and τ(q) curves, and the estimated values of the sparseness parameter C₁ of the UMM indicate that there are three pairs of indices displaying similar scaling properties, namely a_p and X_l, AE and Ni, and F10.7 and Vs. The similarity in the scaling properties of pairs (a_p,X_l) and (AE,Ni) suggests that a_p and X_l, AE and Ni are better correlated - in terms of scaling - than previous thought, respectively. But our results still cannot be used to advance forecasting of a_p and AE by X_l and Ni, respectively, due to some reasons. key Points The scaling properties of the geomagnetic and the solar indices are examinedThe results suggest that multifractality exists in a_p, AE, Xl, and ion densityThe scaling similarity of the a_p and Xl data suggests flare-storm dependence ©2014. American Geophysical Union. All Rights Reserved.

关键词： geomagnetic indices multifractal analysis scaling property solar indices universal multifractal model

来源：评论

学校读者我要写书评

暂无评论

Jacobi spectral Galerkin methods for fractional integro-differential equations

引用

Calcolo 2014年第4期52卷 519-542页

作者： Yang, Yin Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Xiangtan People’s Republic of China

We propose general spectral and pseudo-spectral Jacobi–Galerkin methods for fractional order integro-differential equations of Volterra type. The fractional derivative is described in the Caputo sense. We provide rigorous error analysis for spectral and pseudo-spectral Jacobi–Galerkin methods, which show that the errors of the approximate solution decay exponentially in $$L^\infty $$ norm and weighted $$L^2$$ -norm. The numerical examples are given to illustrate the theoretical results.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A high order composite scheme for the second order elliptic problem with nonlocal boundary and its fast algorithm

引用

Applied Mathematics and Computation 2014年 227卷 212-221页

作者： Cunyun Nie Shi Shu Haiyuan Yu Qianjiang An Department of Mathematics and Physics The Hunan Institution of Engineering Xiangtan City Hunan 411104 China Hunan Key Laboratory for Computation & Simulation in Science and Engineering Key Laboratory of Intelligent Computing & Information Processing of Ministry of Education Xiangtan University Hunan 411105 China Department of Mathematics The Institute of Tongren Guizhou 554300 China

The elliptic problem with nonlocal boundary condition is widely applied in the field of science and engineering. Firstly, we construct a linear finite element scheme for the nonlocal boundary problem, and derive the optimal L 2 error estimate. Then, based on the quadratic finite element and the extrapolation linear finite element methods, we present a composite scheme, and prove that it is convergent order three. Furthermore, we design an upper triangular preconditioning algorithm for the linear finite element discrete system. Finally, numerical results not only validate that the new algorithm is efficient, but also show that the new scheme is convergent order three, furthermore order four on uniform grids.

关键词： The elliptic problem with nonlocal boundary condition The finite element method An upper triangular preconditioner Algebraic multigrid method

来源：评论

学校读者我要写书评

暂无评论

Multifractal analysis of weighted networks by a modified sandbox algorithm

引用

Scientific reports 2015年第1期5卷 17628页

作者： Yu-Qin Song Jin-Long Liu Zu-Guo Yu Bao-Gen Li Hunan Key Laboratory for Computation and Simulation in Science and Engineering and Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education Xiangtan University Xiangtan Hunan 411105 China. College of Science Hunan University of technology Zhuzhou Hunan 412007 China. School of Mathematical Sciences Queensland University of Technology Brisbane Q4001 Australia.

Complex networks have attracted growing attention in many fields. As a generalization of fractal analysis, multifractal analysis (MFA) is a useful way to systematically describe the spatial heterogeneity of both theoretical and experimental fractal patterns. Some algorithms for MFA of unweighted complex networks have been proposed in the past a few years, including the sandbox (SB) algorithm recently employed by our group. In this paper, a modified SB algorithm (we call it SBw algorithm) is proposed for MFA of weighted networks. First, we use the SBw algorithm to study the multifractal property of two families of weighted fractal networks (WFNs): "Sierpinski" WFNs and "Cantor dust" WFNs. We also discuss how the fractal dimension and generalized fractal dimensions change with the edge-weights of the WFN. From the comparison between the theoretical and numerical fractal dimensions of these networks, we can find that the proposed SBw algorithm is efficient and feasible for MFA of weighted networks. Then, we apply the SBw algorithm to study multifractal properties of some real weighted networks - collaboration networks. It is found that the multifractality exists in these weighted networks, and is affected by their edge-weights.

关键词：

来源：评论

学校读者我要写书评

暂无评论

CONVERGENCE ANALYSIS OF THE JACOBI SPECTRAL-COLLOCATION METHOD FOR FRACTIONAL INTEGRO-DIFFERENTIAL EQUATIONS

引用

Acta Mathematica Scientia 2014年第3期34卷 673-690页

作者： Yang Yin Chen Yanping Huang Yunqing Xiangtan University Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan 411105 School of Mathematical Sciences South China Normal University Guangzhou 510631

We propose and analyze a spectral Jacobi-collocation approximation for frac- tional order integro-differential equations of Volterra type. The fractional derivative is de- scribed in the Caputo sense. We provide a rigorous error analysis for the collection method, which shows that the errors of the approximate solution decay exponentially in L~∞ norm and weighted L~2-norm. The numerical examples are given to illustrate the theoretical results.

关键词： Spectral Jacobi-collocation method fractional order integro-differential equa- tions Caputo derivative

来源：评论

学校读者我要写书评

暂无评论

Adaptive mesh refinement and superconvergence for two-dimensional interface problems

引用

SIAM Journal on Scientific Computing 2014年第4期36卷 A1478-A1499页

作者： Wei, Huayi Chen, Long Huang, Yunqing Zheng, Bin Hunan Key Laboratory for Computation and Simulation in Science and Engineering Key Lab. of Intelligent Comp. and Info. Proc. Comp. Min. of Educ. School of Math. and Computational Sci. Xiangtan University Xiangtan Hunan 411105 China Department of Mathematics University of California at Irvine Irvine 92697 CA United States Northwest National Lab Richland 99352 WA United States

Adaptive mesh refinement and the Börgers algorithm are combined to generate a body-fitted mesh which can resolve the interface with fine geometric details. Standard linear finite element method based on such body-fitted meshes is applied to the elliptic interface problem and proven to be superclose to the linear interpolation of the exact solution. Based on this superconvergence result, a maximal norm error estimate of order one and half is obtained without using the discrete maximum principle. The data structure and meshing algorithms, including local refinement and coarsening, are very simple. In particular, no tree structure is needed. An efficient solver for solving the resulting linear algebraic systems is also developed and shown be robust with respect to both the problem size and the jump of the diffusion coefficients. © 2014 Society for Industrial and Applied Mathematics.

关键词： Adaptive mesh refinement Body-fitted mesh Superconvergence

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：