带有分段常数变元的时滞微分方程解的振动性

本文研究了带有分段常数变元的时滞微分方程解的振动性,获得了方程解振动的若干充分条件.     

带有分段常数变元的时滞微分方程解的稳定性和振动性

本文讨论带有分段常数变元的时滞微分方程解的渐性性质。我们利用Ｒａｚｕｍｉｋｈｉｍ方法证明了零解的稳定性，并且改进了文［１］得到的两上振动定理。     

具分段常变元的时滞微分方程的振动性

The delay differential equation with piecewise constant argument x′(t)+a(t)x(t)+b(t)x([t-k])=0 is considered,where a(t) and b(t) are continuous functions on [-k,∞),b(t)≥0,k is a positive integer and [·] denotes the greatest integer function.Some new oscillation and nonoscillation conditions are obtained.     

变量代换法在常微分方程求解中的应用

本文总结归纳了常数代换法在常微分方程中的应用技巧,从而对常微分方程的求解方法进行了拓展.     

线性常微分方程的不变量及其应用

在这篇文章里，我们证明了ｎ阶线性常微分方程在变换Ｔ＝（ｔ）与交换ｘ＝ｕ（ｔ）ｙ下分别有ｎ—１个不变量，并对后一情形给出了不变量的具体表述式．最后，我们还利用这些不变量研究了（１）的解的非振动性等问题．     

常系数非齐次线性微分方程的变量替换法

常系数非齐次线性微分方程求解是微积分教学的一个难点,主要困难是特解形式复杂和计算量大.本文用变量替换的思想研究这类微分方程的特解,从最简单的情形出发,通过类比得出复杂情形下方程的解法.使用变量替换把复杂问题简单化,求解不需要特解形式,有效降低了计算量.     

具分片常变量泛函微分方程的全局稳定性

本文研究具分片常变量泛函微分方程,其中[·]表示取整函数,r(t)∈C([0,+c),(0,+c)),P_i∈[0,+c),(i=1,2,…,m),P_m>0,文中给出了保证方程的每一满足初始条件N(0)=N₀>0,N(-j)=N_-j≥0(j=1,2,…,m),的解N(t)满足lim_t→∞N(t)=N^*的一些新的充分条件.     

一阶非线性脉冲多时滞微分方程的振荡性

研究了具有多时滞的一阶非线性脉冲微分方程的振荡性,同时建立了其振荡准则.这些结果从而优化和发展了以前文献的相关结论.     

具有无界分段常矩阵的n阶微分方程解空间的分解

分段定常系统在微分方程稳定性理论及应用中,特别是在现代科学技术实践中,是一种常见的数学模型。如时变线性微分方程的冻结系统往往就是分段定常系统([1][2])。在文[3]中研究了三阶无界分段定常系统。本文将讨论n阶分段定常系统解的上、下指数并以上下指数为特征将其解空间分解为若干子空间的直接和。所得结论对其稳定性研究和定性研究都提供了重要依据。     

一类自变量分段连续的非线性延迟微分方程数值解振动性

主要考虑一类自变量分段连续的非线性延迟微分方程数值解的振动性.主要通过线性化的理论将非线性方程的振动性转化为线性方程的振动性,从而得到数值解振动的条件,进而得到线性θ-方法保持方程振动性的条件.为了更有力的说明我们的结果,最后给出了相应的算例.     

具有分段常数变元的时滞微分方程解的振动性(英文)

我们获得了带有分段常数变元的时滞微分方程ｘ′（ｔ）＋ａ（ｔ）ｘ（ｔ）＋∑ｍｉ＝１ｂｉ（ｔ）ｘ（［ｔ－ｉ］）＝０，ｔ≥０所有解振动的新的充分条件，这里［·］定义为最大整数函数．我们的结果改进了文献中的某些已知结果．     

Pseudo Almost Periodic Solutions of a Singularly Perturbed Differential Equation with Piecewise Constant Argument

Under suitable assumptions, the existence and the uniqueness of the pseudo-almost periodic solution for a singularly perturbed differential equation with piecewise constant argument are obtained. In addition, the stability properties of these solutions are characterized by the construction of manifolds of initial data.     

A Necessary and Sufficient Condition for the Oscillation of a Delay Equation with Continuous and Piecewise Constant Arguments

In this paper, a necessary and sufficient condition for the oscillation of a delay equation with continuous and piecewise constant arguments is obtained.     

On Quasi-Periodic Solutions of Differential Equations with Piecewise Constant Argument

We study the existence of quasi-periodic solutions to differential equations with piecewise constant argument (EPCA, for short). It is shown that EPCA with periodic perturbations possess a quasi-periodic solution and no periodic solution. The appearance of quasi-periodic rather than periodic solutions is due to the piecewise constant argument. This new phenomenon illustrates a crucial difference between ODE and EPCA. The results are extended to nonlinear equations.     

Some Results Concerning a Class of Differential Equations with Piecewise Constant Argument

Under some conditions the asymptotic behavior of the solutions of a class of differential equations with piecewise constant argument is studied.     

A New Almost Periodic Type Solution of First Order Neutral Delay Differential Equations with Piecewise Constant Argument

In this paper, we introduce a new class of ergodic sequences, pseudo almost periodic sequences, and study the existence of pseudo almost periodic sequences to difference equations. On the basis of these, we investigate the existence of pseudo almost periodic solutions for neutral delay differential equations with piecewise constant argument, Received September 21, 1998, Accepted July 6, 1999     

一类具有逐段常变量微分方程的渐近概周期解

利用差分方程的渐近概周期序列解，讨论了一类具有逐段常变量微分方程的渐近概周期解的存在性．