周期系数二阶线性微分方程的稳定性

讨论周期系数二阶线性微分方程的稳定性问题,给出了判定稳定性较精确的方法,利用这个方法,获得了判定稳定性简洁而实用的若干准则。     

一类多项式系数二阶线性微分方程解法的研究

给出了一类具有多项式系数的二阶线性微分方程有多项式型特解和通解的充要条件,并在Maple下实现了这类微分方程具有多项式型特解和通解自动判定和求解的算法.     

一类二阶半线性时滞微分方程解的振动性质

研究了一类二阶半线性时滞微分方程解的振动性质.在一定条件下,建立了两个新的振动性定理,推广和改进了已知的结果.     

变系数二阶线性微分方程的一个新的可解类型

通过双变换——未知函数的线性变换和自变量变换 ,将一类变系数线性微分方程化为二阶常系数线性微分方程 ,从而得到变系数二阶线性微分方程的一个新的可解类型 ,推广了著名的二阶 Euler方程 .     

二阶变系数线性系统的稳定性

本文研究变系数二阶线性微分方程组零解的稳定性。引入了时变方向场的概念，用定性方法建立了稳定及不稳定的定理。     

二阶变系数线性微分方程的解法探讨

给出了变系数满足几种特定条件的二阶变系数齐次线性微分方程的特解形式,得到了一个命题.之后通过几个典型实例验证了命题在求解几类二阶变系数线性微分方程特解和通解中的有效性.     

一些特殊类型的变系数二阶线性微分方程解法的研究

运用变量变换的方法将一些特殊类型的变系数二阶线性微分方程化为常系数二阶线性微分方程,或已知齐次方程的一个解来求出齐次方程的另一个线性无关解,从而达到按照常系数二阶线性微分方程的特殊方法和利用常数变易法来求方程的通解的目的,同时纠正了文献[3]的结论和例子2的错误.     

一类二阶变系数非齐次线性微分方程的通解

通过在二阶变系数非齐次线性微分方程两边同乘以某个积分因子将该方程转化为常系数非齐次线性微分方程,进而得出二阶变系数非齐次线性微分方程的通解公式.     

一类二阶变系数线性微分方程及其解的构造方法

利用构造法构造二阶变系数线性齐次微分方程及其解,根据这种方法也能求得某些二阶变系数线性齐次微分方程的非零解,并给出了二阶变系数线性齐次微分方程存在非零解的充要条件.     

关于二阶线性周期微分方程的次正规解

研究了一类二阶周期系数线性微分方程的次正规解的存在性和形式, 以及估计了所有解的增长性, 回答了Gundersen 和 Steinbart提出的一个问题.     

The quasiderivative method for derivative estimates of solutions to degenerate elliptic equations

We give an example of quasiderivatives constructed by random time change, Girsanov’s Theorem and Levy’s Theorem. As an application, we investigate the smoothness and estimate the derivatives up to second order for the probabilistic solution to the Dirichlet problem for the linear degenerate elliptic partial differential equation of second order, under the assumption of non-degeneracy with respect to the normal to the boundary and an interior condition to control the moments of quasiderivatives, which is weaker than non-degeneracy.     

On periodic solutions of linear degenerate second-order ordinary differential equations

We consider a scalar linear second-order ordinary differential equation whose coefficient of the second derivative may change its sign when vanishing. For this equation, we obtain sufficient conditions for the existence of a periodic solution in the case of arbitrary periodic inhomogeneity.     

非自治Lienard型系统的周期解

利用Mawhin的重合度理论及Brousk定理给出了一类非自治二阶微分系统周期解存在的一些充分条件，所获结果推广与扩展了有关文献的相应结果。     

二阶常系数线性微分方程的积分形式通解及首次积分

利用一阶线性微分方程的通解 ,导出了二阶常系数线性微分方程的积分形式通解 .研究了通解的结构 ,并给出了首次积分 .     

关于三阶变系数线性微分方程解的不稳定性

文献[1]用李雅普诺夫第二方法证明了特征根均具有负实部的缓变系数动力系统的渐近稳定性.本文也用李雅普诺夫第二方法给出至少有一个特征根具有正实部的三阶变系数线性微分方程解的不稳定性的充分条件.     

THE ESTIMATION OF CHARACTERISTIC EXPONENTS FOR A CLASS OF SECOND ORDER LINEAR DIFFERENTIAL EQUATION WITH PERIODIC COEFFICIENTS

In this paper we shall give a simple and easy method to estimate the characteristic exponents for a class of second order linear different equation with periodic coefficient which frequently occurs in application.     

Stochastic semidiscretization method: Second moment stability analysis of linear stochastic periodic dynamical systems with delays

In this paper, an efficient numerical approach is presented, which allows the analysis of the moment dynamics, stability, and stationary behavior of linear periodic stochastic delay differential equations. The method leads to a high dimensional stochastic mapping with periodic statistical properties, from which the periodic first and second moment mappings are derived. The application of the method is demonstrated first through the analysis of the stochastic delay Mathieu equation. Then a practical case study, where the effect of spindle speed variation on the stability and the resulting surface quality of turning operations is investigated.     

具无穷时滞高阶中立型微分方程的周期解

利用重合度理论研究了一类具有无穷时滞高阶中立型泛函微分方程周期解的存在性,获得了该方程存在周期解的充分条件,推广和改进了二阶方程的相应结果.     

Periodic first order linear neutral delay differential equations

Some new asymptotic and stability results are given for a first order linear neutral delay differential equation with periodic coefficients and constant delays. The asymptotic behavior of the solutions and the stability of the trivial solution are described by the use of an appropriate real root of an equation, which is in a sense the corresponding characteristic equation.