利用再生核解一类变系数偏微分方程

如何求解偏微分方程,已经成为各个领域内非常重视的课题.在再生核空间中,给出了变系数偏微分方程的级数形式精确解,为了数值计算,给出了一个迭代方法,并证明了迭代方法的收敛性.数值算例表明本文方法是有效的而且具有良好的实用性.     

一类常系数非齐次微分方程的特解

针对非齐次自由项分别为(a0+a1x)cosλx,(a0+a1x)sinλr,和(ao+a1x)eλxi的三种二阶常系数非齐次线性微分方程,利用变换和升阶法推导出它们的特解表达式.     

一类常系数线性微分方程特解的求法

针对一类常系数线性微分方程,运用观察法或特征函数导数法,得到了方程特解的计算公式.当方程非齐次项Aeαx中α=0时,可采用观察法;当α≠0时,可采用特征函数导数法得到方程的一个公式化特解.该方法简便易行,特解形式直观,避免了以前方法计算量过大的不足.     

一类变系数线性偏微分方程的全局可解性

本文应用Euler变换讨论一类变系数线性偏微分方程的可解性,得到了全局可解性。     

一类变系数微分方程的通解

本文给出了一类变系数二阶线性微分方程的通解公式，进而得到了一批变系数微分方程的通解．     

一类二阶常微分方程的特解

研究一类二阶实常系数非齐次微分方程y″+py′+q=(a0+a1x)eαxsinβx的解法,应用叠加原理和Euler公式,将其化为二阶线性非齐次方程,并利用对应的特征方程给出了这一类方程特解的一般公式,简化这一类微分方程的求解过程.     

一类具偏差变元非线性偏微分方程解的振动性

研究了一类具有偏差变元的非线性偏微分方程解的振动性，获得了方程所有解振动的充分条件。     

一类常系数非齐次线性微分方程的特解公式

给出了一类常系数非齐次线性微分方程的特解的计算公式.     

一类二阶常系数非齐次线性微分方程的特解求法

以二阶常系数非齐次线性微分方程为例,讨论教材中两种类型的特解求法,在教材和相关文献的基础上介绍一种相对简单的方法.     

一类具变号系数的二阶非线性变时滞微分方程的振动性

研究一类二阶非线性变时滞微分方程x″(t)+p(t)f(x(g(t)))=0的振动性,对振动因子p(t)可变符号的情况,通过两个引理,得出了方程振动的两个充分性定理.所得结论推广了二阶非线性变时滞微分方程当系数不变号时的振动性结论.     

Exact Solutions of Linear Partial Differential Equations with Variable Coefficients

Bäcklund transformations relating the solutions of linear PDE with variable coefficients to those of PDE with constant coefficients are found, generalizing the study of Varley and Seymour [2]. Auto-Bäcklund transformations are also determined. To facilitate the generation of new solutions via Bäcklund transformation, explicit solutions of both classes of the PDE just mentioned are found using invariance properties of these equations and other methods. Some of these solutions are new.     

一类非线性偏微分方程组的解析解

首先,利用共轭算子的性质,将张鸿庆等提出的求伴随算子对的方法推广到了求一类非线性(即部分非线性的)算子矩阵的伴随算子向量．其次,利用机械化的构造方法给出了求解一类非线性(即,部分非线性的,且以所有线性的为其特例)非齐次微分方程组的统一理论,即通过齐次化和三角化求得恰当的变换,从而将原方程组化为较简单的形式,一般为对角化的．最后利用该方法求得了一些弹性力学方程组的解析解．     

带有三系数的一类偏差分方程的振动性

主要研究了偏差分方程um+3,n+um,n+3+pum+1,n+qum,n+1+rum,n=0,解的振动性,其中参数p,q, r∈R,m,n∈N.     

Summability of Formal Power-Series Solutions of Partial Differential Equations with Constant Coefficients

We study Gevrey properties and summability of power series in two variables that are formal solutions of a Cauchy problem for general linear partial differential equations with constant coefficients. In doing so, we extend earlier results in two articles of Balser and Lutz, Miyake, and Schäfke for the complex heat equation, as well as in a paper of Balser and Miyake, who have investigated the same questions for a certain class of linear PDE with constant coefficients subject to some restrictive assumptions. Moreover, we also present an example of a PDE where the formal solution of the Cauchy problem is not k-summable for whatever value of k, but instead is multisummable with two levels under corresponding conditions upon the Cauchy data. That this can occur has not been observed up to now.     

Probabilistic Representation of Weak Solutions of Partial Differential Equations with Polynomial Growth Coefficients

In this paper we develop a new weak convergence and compact embedding method to study the existence and uniqueness of the L_r^2p(\mathbbR^d;\mathbbR¹)×L_r²(\mathbbR^d;\mathbbR^d)L_{\rho}^{2p}({\mathbb{R}^{d}};{\mathbb{R}^{1}})\times L_{\rho}^{2}({\mathbb{R}^{d}};{\mathbb{R}^{d}}) valued solution of backward stochastic differential equations with p-growth coefficients. Then we establish the probabilistic representation of the weak solution of PDEs with p-growth coefficients via corresponding BSDEs.     

A Method for Obtaining Exact Solutions to Partial Differential Equations with Variable Coefficients

This paper describes techniques that can be used to transform PDEs with variable coefficients into equations with constant coefficients. The techniques are illustrated by calculating shear flows over quite general surfaces, by solving the signaling problem for diffusive processes in inhomogeneous materials, and by solving the signaling problem for acoustical waves when the sound speed varies with distance. The techniques may also be used to solve equations governing processes in inhomogeneous, anisotropic materials.     

一类具时滞的高阶中立型偏微分方程解的振动性

研究一类具时滞的偶数阶非线性中立型偏微分方程解的振动性,获得了一些新的充分判据,所得结果推广和包含了文[1]及[2]的相应结果.     

Convergence of Weighted Polynomial Approximations to Solutions of Partial Differential Equations with Quasianalytical Coefficients

Sequences of polynomial functions which converge to solutions of partial differential equations with quasianalytical coefficients are constructed. Estimates of the degree of convergence are also given.