应用F展开法求KdV方程的周期波解

提出了求非线性数学物理演化方程周期波解的F展开法,该方法可看作最近提出的扩展的Jacobi椭圆函数展开方法的浓缩.直接利用F展开法而不计算Jacobi椭圆函数,我们可同时得到著名的KdV方程的多个用Jacobi椭圆函数表示的周期波解.当模数m→1 时,可得到双曲函数解(包括孤立波解).     

Davey StewartsonⅠ的周期波解

利用新近提出的F展开法，导出了Davey StewartsonⅠ方程的由Jacobi椭圆函数表示的周期波解；并且在极限的情况下，得到了Davey StewartsonⅠ方程的孤波解以及其他形式解.     

2+1 维变系数广义KP方程的椭圆周期解

运用Jacobi椭圆函数展开法求得了2 1维变系数广义KadoratsevPetviashvili方程的椭圆周期解及孤立波解．     

Klein-Gordon-Zakharov方程组的周期波解

通过使用符号计算系统Mathematica,并借助于推广的F-展开法,我们得到了Klein- Gordon-Zakharov方程组的用不同Jacobi椭圆函数表示的一系列周期波解．在极限情况下,还求出了对应的孤立波解．     

广义随机KP方程的椭圆周期解

利用Hermite变换和Jacobi椭圆函数展开法研究(2+1)-维广义随机Kadomtsev-Petviashvili方程,并给出了它的随机椭圆周期解及随机孤立波解.     

准一维单原子晶格非线性振动方程的双周期解

利用行波变量代换和辅助椭圆方程法,求解了准一维单原子非线性晶格振动方程,得到了新的双周期波形式的椭圆函数解.在极限情形下,不仅可以还原为前人给出的扭结孤子解,同时还给出了一类新的类孤子解.     

耦合的凝聚态Bose-Einstein方程的双周期解

本文通过引入参数假设,利用雅可比椭圆函数展开法,得到了自散焦的耦合非线性Schr(o)dinger(NLS)方程的四种双周期解(雅可比椭圆函数).     

关于Jacobi椭圆函数展开法

主要利用Jacobi椭圆函数所满足的方程并用其解代替Jacobi椭圆函数以求非线性偏微分方程的周期解,并举例说明该方法的应用.     

Zhiber-Shabat方程的孤立波解与周期波解

结合齐次平衡法原理并利用F展开法,再次研究了Zhiber-Shabat方程的各种椭圆函数周期解.当椭圆函数的模m分别趋于1或0时,利用这些椭圆函数周期解,得到了Zhiber-Shabat方程的各种孤子解和三角函数周期解,从而丰富了相关文献中关于Zhiber-Shabat波方程的解的类型.     

推广的β平面近似下带有外源和耗散强迫的非线性Boussinesq方程及其孤立波解

在推广的β平面近似下,从包含耗散和外源的准地转位涡方程出发,利用Gardner-Morikawa变换和弱非线性摄动展开法,推导出带有外源和耗散强迫的非线性Boussinesq方程去刻画非线性Rossby波振幅的演变和发展.利用修正的Jacobi椭圆函数展开法,得到Boussinesq方程的周期波解和孤立波解,从解的结构分析了推广的β效应、切变基本流、外源和耗散是影响非线性Rossby波的重要因素.     

Single-Phase averaging for the Ablowitz-Ladik chain

The Bogolyubov-Whitham averaging method is applied to the Ablowitz-Ladik chain $$ \begin{gathered} - i\dot q_n - (1 - q_n r_n )(q_{n - 1} + q_{n + 1} ) + 2q_n = 0, \hfill \\ - i\dot r_n + (1 - q_n r_n )(r_{n - 1} + r_{n + 1} ) + 2r_n = 0 \hfill \\ \end{gathered} $$ in the single-phase case. We consider an averaged system and prove that the Hamiltonian property is preserved under averaging. The single-phase solutions are written in terms of elliptic functions and, in the “focusing” case, Riemannian invariants are obtained for modulation equations. The characteristic rates of the averaged system are stated in terms of complete elliptic integrals and the self-similar solutions of the systemare obtained. Results of the corresponding simulations are given.     

Numerical solutions of coupled systems of nonlinear elliptic equations

This article deals with numerical solutions of a general class of coupled nonlinear elliptic equations. Using the method of upper and lower solutions, monotone sequences are constructed for difference schemes which approximate coupled systems of nonlinear elliptic equations. This monotone convergence leads to existence‐uniqueness theorems for solutions to problems with reaction functions of quasi‐monotone nondecreasing, quasi‐monotone nonincreasing and mixed quasi‐monotone types. A monotone domain decomposition algorithm which combines the monotone approach and an iterative domain decomposition method based on the Schwarz alternating, is proposed. An application to a reaction‐diffusion model in chemical engineering is given. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 28: 621–640, 2012     

Ambrosio-Tortorelli approximation of quasi-static evolution of brittle fractures

We define a notion of quasistatic evolution for the elliptic approximation of the Mumford-Shah functional proposed by Ambrosio and Tortorelli. Then we prove that this regular evolution converges to a quasi static growth of brittle fractures in linearly elastic bodies.Received: 1 January 2003, Accepted: 29 January 2004, Published online: 12 May 2004Mathematics Subject Classification (2000): 35R35, 74R10, 35J25     

Multiperiodic multifractal martingale measures

A nonnegative 1-periodic multifractal measure on is obtained as infinite random product of harmonics of a 1-periodic function W(t). Such infinite products are statistically self-affine and generalize certain Riesz products with random phases. They are martingale structures, therefore converge. The criterion on W for nondegeneracy is provided. It differs completely from those for other known random measures constructed as martingale limits of multiplicative processes. In particular, it is very sensitive to small changes in W(t). When these infinite products are interpreted in the framework of thermodynamic formalism for random transformations, logW is a potential function when W>0. For regular enough potentials, in case of degeneracy, the natural normalization makes the sequence of measures converge. Moreover, this normalization is neutral for nondegenerate martingales. The multifractal analysis of the limit martingale measure is performed for a class of potential functions having a dense countable set of jump points.     

An Elliptic Non Distributive Algebra

In this paper we extend the results of hyperbolic scator algebra introduced in [5], to consider an elliptic product in a subset of ${\mathbb{R}^{1 + n}}$ which recovers the field of complex numbers when only one director component is present. The product of this algebra, that we call elliptic scator algebra in ${\mathbb{E}^{1 + n}}$ , is associative and commutative provided that divisors of zero are excluded. However, as with the hyperbolic case, the elliptic product is not distributive over addition. We explore the geometry of this algebra by considering some interesting objects, such as spheres.     

Spectral Estimates for Resolvent Differences of Self-Adjoint Elliptic Operators

The concept of quasi boundary triples and Weyl functions from extension theory of symmetric operators in Hilbert spaces is developed further and spectral estimates for resolvent differences of two self-adjoint extensions in terms of general operator ideals are proved. The abstract results are applied to self-adjoint realizations of second order elliptic differential operators on bounded and exterior domains, and partial differential operators with δ-potentials supported on hypersurfaces are studied.     

关于共轭温度系统的 Herz-型Hardy 空间

记（ｎ－１）／ｎ〈ｐ〈ｑ〈∞,１〈ｐ,且α＝ｎ（１／ｐ－１／ｑ）。本文引进了关于Ｒ＾（ｎ＋１）上温度函数的共轭系统的Ｈｅｒ－型Ｈａｒｄｙ空间ＴＨＫｑ＾（α,ｐ）（Ｒ＾ｎ）,并且证明了它们的边值分布等同于通常的调和函数的共轭系统的Ｈｅｒｚ－型Ｈａｒｄｙ空间ＨＫｑ＾（α,ｐ）（Ｒ＾ｎ）。     

Über eine partielle Differentialgleichung mit p+2 Variablen und deren Zusammenhang mit den allgemeinen Kugelfunktionen

This paper essentially deals with operators that map harmonic functions into solutions of a class of elliptic partial differential equations in p+2 variables. Starting with the representation by means of integral operators, obtained by R. P. Gilbert, a representation free of integrals is derived by using the properties of the Riemann function. This operator has a very simple form-there are only used differential operators with respect to a parameter. Furthermore,with this result, we are able to give a representation formula for the Spherical Harmonics of degree N in 2l+1 dimensions, similar to that given by K. W. Bauer.     

Eine verallgemeinerte Darboux-Gleichung I

The paper is concerned with the elliptic equation $$\begin{gathered} w_{z\bar z} + \left[ {\frac{{n (n + 1)}}{{(z - \bar z)^2 }} - \frac{{m (m + 1)}}{{(z + \bar z)^2 }} + \frac{{q (q + 1)}}{{(1 + z\bar z)^2 }} - \frac{{p (p + 1)}}{{(1 - z\bar z)^2 }}} \right]w = 0, \hfill \\ n, m, p, q \in \mathbb{N}_0 . \hfill \\ \end{gathered} $$ General representation theorems for, the solutions are derived by differential operators if three parameters are different from zero or two parameters are equal. Some applications are given to pseudo-analytic functions and generalized Tricomi equations.     

Eine verallgemeinerte Darboux-Gleichung II

The paper is concerned with the elliptic equation $$\begin{gathered} w_{z\bar z} + \left[ {\frac{{n(n + 1)}}{{(z - \bar z)^2 }} - \frac{{m(m + 1)}}{{(z + \bar z)^2 }} + \frac{{q(q + 1)}}{{(1 + z\bar z)^2 }} - \frac{{p(p + 1)}}{{(1 - z\bar z)^2 }}} \right]w = 0, \hfill \\ n,m,p,q \in \mathbb{N}_0 . \hfill \\ \end{gathered}$$ General representation theorems for the solutions are derived by differential operators if three parameters are different from zero or two parameters are equal. Some applications are given to pseudo-analytic functions and generalized Tricomi equations.