检索结果-南通市图书馆

An Application of a Mountain Pass Theorem

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2002年第1期18卷 27-36页

作者： ZHOU Huan Song Laboratory of Mathematical physics. wuhan {2. of physics and mathematics. chinese academy of sciences, P. O. Box 71010, wuhan 430071. P. R. china Laboratory of Mathematical physics Wuhan Instiute of Physics and Mathematics Chinese Academy of Sciences Wuhan P. R. China

We are concerned with the following Dirichlet problem: -△u(x) = f(x, u), x ∈ Ω. u ∈ H_0~1(Ω). (P) where f(x, t) ∈ C(Ω×R), f(x, t)/t is nondecreasing in t ∈ R and tends to an L~∝-function q(x) uniformly in x ∈ Ω as t→+∝ (i.e., f(x, t) is asymptotically linear in t at infinity). In this case. an Ambrosetti-Rabinowitz-type condition, that is. for some θ>2. M>0, 0<θF(x. s)≤ f(x, s)s, for all |s|≥M and x ∈ Ω, (AR) is no longer true, where F(x, s) = integral from n=0 to s f(x, t)dt. As is well known, (AR) is an important technical condition in applying Mountain Pass Theorem. In this paper, without assuming (AR) we prove, by using a variant version of Mountain Pass Theorem, that problem (P) has a positive solution under suitable, conditions on f(x, t) and q(x). Our methods also work for the case where f(x, f) is superlinear in t at infinity. i.e., q(x) ≡∞.

关键词： Dirichlet problem Mountain Pass Theorem Asymptotically linear Resonant problem

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

在线全文

学校读者我要写书评

暂无评论

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 430072.china 2. Laboratory of Computational physics,institute of Applied physics and Computational mathematics,Beijing 100088. china 1. Department of mathematics Wuhan University 430072 Wuhan China 2. Laboratory of Computational physics Institute of Applied Physics and Computational Mathematics 100088 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.

TIME-IGGCAS model validation:Comparisons with empirical models and observations

在线全文

学校读者我要写书评

暂无评论

Science china Technological sciences 2008年第3期51卷 308-322页

作者： YUE XinAn1,2.3, WAN WeiXing1, LIU LiBo1, NING BaiQi1, ZHAO BiQiang1 & ZHANG ManLian1 1 institute of Geology and Geophysics,{2., Beijing 10002., china 2.wuhan institute of physics and mathematics,{2., wuhan 430071, china 3 Graduate University,{2., Beijing 100049, china 1. institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China 2. wuhan institute of physics and mathematics Chinese Academy of Sciences Wuhan 430071 China 3. chinese academy of sciences Graduate University Beijing 100049 China

The TIME-IGGCAS (Theoretical Ionospheric Model of the Earth in institute of Ge- ology and Geophysics,{2.) has been developed re- cently on the basis of previous works. To test its validity, we have made compari- sons of model results with other typical empirical ionospheric models (IRI, NeQuick-ITUR, and TItheridge temperature models) and multi-observations (GPS, Ionosondes, Topex, DMSP, FORMOSAT, and CHAMP) in this paper. Several conclu- sions are obtained from our comparisons. The modeled electron density and elec- tron and ion temperatures are quantitatively in good agreement with those of em- pirical models and observations. TIME-IGGCAS can model the electron density variations versus several factors such as local time, latitude, and season very well and can reproduce most anomalistic features of ionosphere including equatorial anomaly, winter anomaly, and semiannual anomaly. These results imply a good base for the development of ionospheric data assimilation model in the future. TIME-IGGCAS underestimates electron temperature and overestimates ion tem- perature in comparison with either empirical models or observations. The model results have relatively large deviations near sunrise time and sunset time and at the low altitudes. These results give us a reference to improve the model and enhance its performance in the future.

关键词： ionosphere theoretical model empirical model satellite observation relative deviation

BIHARMONIC EQUATIONS WITH ASYMPTOTICALLY LINEAR NONLINEARITIES

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2007年第3期27卷 549-560页

作者：刘玥王征平 wuhan institute of {2. and mathematics Chinese Academy of sciences

This article considers the equation △2. = f（x,u）with boundary conditions either u｜aΩ = au/an｜aΩ = 0 or u｜aΩ = △u｜aΩ = 0, where f（x, t） is asymptotically linear with respect to t at infinity, and Ω is a smooth bounded domain in R^N, N 〉 4. By a variant version of Mountain Pass Theorem, it is proved that the above problems have a nontrivial solution under suitable assumptions of f（x, t）.

关键词： Biharmonic mountain pass theorem asymptotically linear

Multifractal Decomposition of Statistically Self-Similar Sets

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2001年第3期17卷 507-516页

作者： Jing Hu YU wuhan institute of {2. and mathematics,The chinese academy of sciences,wuhan 430071,P.R.china E-mail:ding@wipm.whcnc.ac.cnDi He HU College of mathematics and Statistics.wuhan University,wuhan 430072.P.R.china E-mail:dhhu@*** wuhan institute of {2. and mathematics The Chinese Academy of Sciences Wuhan 430071 P. R. China College of mathematics and Statistics Wuhan University Wuhan 430072 P. R. China

Let K be a statistically self-similar set defined by *** this paper,we construct a random measure ρ which is supported by K and study the multifractal decomposition for K with p. Under such a decomposition,we obtain ... 详细信息

关键词： Statistically self-similar sets Multifractal decomposition Spectrum function

COLLECTIVELY COMPACT COMPOSITION OPERATOR SEQUENCES BETWEEN BERGMAN AND HARDY SPACES

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2004年第2期24卷 206-212页

作者：王茂发刘培德 SchoolofmathematicsandStatistics WuhanUniversityWuhan430072China

This paper studies the collective compactness of composition operator sequences between the Bergman and Hardy spaces. Some sufficient and necessary conditions involving the generalized Nevanlinna counting functions fo... 详细信息

关键词： Bergman space Hardy space composition operator collectively compact operator sequence

Photodissociation/photoionization processes of chlorobromomethane induced by femtosecond laser pulses with pump-probe scheme

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2008年第5期53卷 681-686页

作者： ZHANG Feng1,2. WEI ZhengRong1,2. CAO ZhenZhou1,2. ZHANG ChangHua1,2.& ZHANG Bing1,2.1 State Key Laboratory of Magnetic Resonance and Atomic and Molecular physics, wuhan {2. of physics and mathematics, chinese academy of sciences, wuhan 430071, china 2.Graduate University of chinese academy of sciences, Beijing 100039, china State Key Laboratory of Magnetic Resonance and Atomic and Molecular physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan China Graduate University of chinese academy of sciences Beijing China

The photodissociation/photoionization processes of chlorobromomethane (CH_2.rCl) induced by fem- tosecond laser pulses have been investigated using pump-probe scheme combined with the time-of-flight mass spectra. The dominate photoproducts are observed at different delay time of the pump (400 nm) and probe (800 nm) pulses and the corresponding time-dependence of them is obtained. The results show that the decaying time of the molecule CH_2.rCl in the A-band is in the 100 fs. The decaying tendencies of the fragment ions (CH_2.l^+ and CH_2.r^+) and the parent ion (CH_2.rCl^+) are almost the same and the relative ratios of the yields of them keep constant during the delay time of 0 to 150 fs. These facts suggest that the fragment ions come from the fragmentation of the parent ions in excited electronic states. The probabilities to form CH_2.l^+ and CH_2.r^+ are obtained from the relative ratio of the ion intensity and are about 71.6% and 14.2., respectively.

关键词：毫微秒激光氯溴化甲烷激光探针光解作用光化电离作用

MULTI-DIMENSIONAL GEOMETRIC BROWNIANMOTIONS, ONSAGER-MACHLUP FUNCTIONS, AND APPLICATIONS TO MATHEMATICAL FINANCE

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2000年第3期20卷 341-358页

作者：胡耀忠 Univ Kansas Dept Math Lawrence KS 66045 USA chinese Acad Sci Wuhan Inst Phys & Math Wuhan 430071 Peoples R China

The solutions of the following bilinear stochastic differential equation are studied [GRAPHICS] where A(t)(k), B-t are (deterministic) continuous matrix-valued functions of t and w(1) (t),..., w(m) (t) are m independent standard Brownian motions. Conditions are given such that the solution is positive if the initial condition is positive. The equation the most probable path must satisfy is also derived and applied to a mathematical finance problem.

关键词： multi-dimensional geometric Brownian motions Onsager-Machlup functions most probable path positivity most likely interest rate

POINTWISE MULTIPLIERS OF DIRICHLET TYPE SPACES ON THE UNIT BALL OF C^n

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2001年第3期14卷 306-310页

作者： FENG Shaoji (institute of Systems Science, academy of {2. and Systems Science, chinese academy of sciences, Beijing 100080 wuhan institute of physics and {2., chinese academy of sciences, wuhan 430071, china) 中科院系统科学所北京 100080

In this paper, we establish a criterion for a holomorphic function to be a pointwise multiplier of Dirichlet type spaces, and use this criterion to consider the inclusion relations among M(Dr), α-Bloch spaces and Qp ... 详细信息

关键词： Dirichlet type spaces pointwise multipliers inclusion relation.