Criteria for System of Three Second-Order Ordinary Differential Equations to Be Reduced to a Linear System via Restricted Class of Point Transformation

This paper is devoted to the study of the linearization problem of system of three second-order ordinary differential equations and . The necessary conditions for linearization by general point transformation and are found. The sufficient conditions for linearization by restricted class of point transformation and are obtained. Moreover, the procedure for obtaining the linearizing transformation is provided in explicit forms. Examples demonstrating the procedure of using the linearization theorems are presented.

A HIGH ACCURACY DIFFERENCE SCHEME FOR THE SINGULAR PERTURBATION PROBLEM OF THE SECOND-ORDER LINEAR ORDINARY DIFFERENTIAL EQUATION IN CONSERVATION FORM

In this paper, combining the idea of difference method and finite element method, we construct a difference scheme for a self-adjoint problem in conservation form. Its solution uniformly converges to that of the original differential equation problem with order h3.

DIFFERENTIATOR SERIES SOLUTION OF LINEAR DIFFERENTIAL ORDINARY EQUATION

In this paper, the principle techinique of the differentiator method, and some examples using the method to obtain the general solution and special solution of the differential equation are introduced. The essential difference between this method and the others is that by this method special and general solutions can be obtained directly with the operations of the differentor in the differential equation and without the enlightenment of other scientific knowledge.

Existence and Multiplicities of Solutions for Asymptotically Linear Ordinary Differential Equations Satisfying Sturm-Liouville BVPs with Resonance

In this paper, we prove existence and multiplicities of solutions for asymptotically linear ordinary differential equations satisfying Sturm-Liouville boundary value conditions with resonance. Adding assumption H3 that is similar to (LL) in Theorem 1.1, by index theory and Morse theory, we obtain more nontrivial solutions.

THE ESTIMATION OF SOLUTION OF THE BOUNDARY VALUE PROBLEM OF THE SYSTEMS FOR QUASI-LINEAR ORDINARY DIFFERENTIAL EQUATIONS

This paper deals with the singular perturbation of the boundary value problem of the systems for quasi-linear ordinary differential equationswhere x,f, y , h, A, B and C all belong to Rn , and g is an n×n matrix function. Under suitable conditions we prove the existence of the solutions by diagonalization and the fixed point theorem and also estimate the remainder.

INSTABILITY OF SOLUTION FOR THE FOURTH ORDER LINEAR DIFFERENTIAL EQUATION WITH VARIED COEFFICIENT

In this paper, we give some sufficient conditions of the instability for the fourth order linear differential equation with varied coefficient, at least one of the characteristic roots of which has positive real part, by means of Liapunov's second method.

Linearization of Emden Differential Equation via the Generalized Sundman Transformations

The Emden differential equation is one of the most widely studied and challenging nonlinear dynamics equations in literature. It finds applications in various areas of study such as celestial mechanics, fluid mechanics, Steller structure, isothermal gas spheres, thermionic currents and so on. Because of the importance of the equation, the method of generalized Sundman transformation (GST) as proposed by Nakpim and Meleshko is used for linearizing the Emden differential equation. The Emden differential equation considered here is a modification of the equation given by Berkovic. The results obtained in this paper imply that the Emden equation cannot be linearized by a point transformation. The general solution of the modified Emden equation is also obtained.

一类常微分方程的反问题

研究一类常微分方程的反问题:任给函数组,求以函数组为解的常微分方程.应用待定系数法,在不同条件下,构造了两种以函数组为解的常微分方程,包括高阶非齐次线性微分方程和一阶非线性微分方程,最后通过实例对构造方法进行应用.

ACCURATE ESTIMATES OF CHARACTERISTIC EXPONENTS FOR SECOND ORDER DIFFERENTIAL EQUATION

In this paper, a second order linear differential equation is considered, and an accurate estimate method of characteristic exponent for it is presented. Finally, we give some examples to verify the feasibility of our result.

High Accuracy Arithmetic Average Discretization for Non-Linear Two Point Boundary Value Problems with a Source Function in Integral Form

In this article, we report the derivation of high accuracy finite difference method based on arithmetic average discretization for the solution of Un=F(x,u,u′)+∫K(x,s)ds , 0 x s < 1 subject to natural boundary conditions on a non-uniform mesh. The proposed variable mesh approximation is directly applicable to the integro-differential equation with singular coefficients. We need not require any special discretization to obtain the solution near the singular point. The convergence analysis of a difference scheme for the diffusion convection equation is briefly discussed. The presented variable mesh strategy is applicable when the internal grid points of the solution space are both even and odd in number as compared to the method discussed by authors in their previous work in which the internal grid points are strictly odd in number. The advantage of using this new variable mesh strategy is highlighted computationally.

Inequalities for Sums and Products of Complex Zeros of Solutions to ODE with Polynomial Right Parts

The paper is devoted to non-homogeneous second-order differential equations with polynomial right parts and polynomial coefficients.We derive estimates for the partial sums and products of the zeros of solutions to the considered equations.These estimates give us bounds for the function counting the zeros of solutions and information about the zero-free domains.

非线性动力系统刚性方程精细时程积分法

讨论了非线性动力系统刚性常微分方程的数值积分算法,给出了非线性动力系统刚性方程的单步精细时程积分法.揭示了精细时程积分不仅具有显式积分格式,而且具有绝对稳定性和高精度的特点,避免了刚性方程的计算危险性.算例进一步表明了精细时程积分算法求解刚性方程的有效性.

磁浮列车的动力稳定性分析与Liapunov指数

针对弹性轨道上的磁悬浮列车线性动力控制系统，给出了采用Ｌｉａｐｕｎｏｖ特性指数判别动力系统稳定性的判据：当动力系统的全部Ｌｉａｐｕｎｏｖ特性指数小于零时，动力控制系统是稳定的；而当动力系统中有一Ｌｉａｐｕｎｏｖ特性指数大于零时，动力系统就成为不稳定的．由于Ｌｉａｐｕｎｏｖ特性指数可以由数值积分方式方便地给出，这一判断方法对于不便搜索参数稳定区域的高维动力系统，与寻求周期变系数线性常微分方程动力系统的Ｆｌｏｑｕｅｔ理论的变换矩阵特征值相比，具有计算量小和搜索方法简单等优点．数值算例表明本文方法是有效的．

弯曲井眼中受压管柱的屈曲分析

本文通过微元体的变形和受力分析，导出了弯曲井眼中受压管柱的屈曲方程──一个合参数。的四阶非线性常微分方程。ε是一个综合考虑轴压（Ｆ０）、管柱截面抗弯刚度（ＥＪ）、井眼轴线轨迹曲车半径（Ｒ）以及共眼有效半径（ｒ）的无因次参数。本文利用线性化方法及小参数摄动法求得了屈曲方程的一次分叉点ε１及二次分叉点ε２。当ε＞ε１时，管柱处于稳定状态，对应于屈曲方程的零解；当ε２＜ε≤ε１时，管柱处于正弦屈曲状态，对应于屈曲方程的周期解；当ε≤ε２时，管柱处于螺旋屈曲状态，对应于屈曲方程的螺线解。本文给出的弯曲井眼中受压管柱的两个临界屈曲载荷（与两个分叉声、对应），发生螺旋屈曲时的螺距等理论结果与他人发表的实验结果吻合较好。

线性微分方程的微分算子级数解法

介绍了微分算子级数法及其求解线性常微分方程通解、特解的原理、方法和实例·这个方法和其它解法的差别，在于不借助其它学科知识的启示。

二阶线性常微分方程的两点边值问题的新解法

基于变分原理,将二阶线性常微分方程的两点边值问题转化为等价的变分问题（即泛函极值问题）,利用两点三次Hermite插值构造一个逼近可行函数的近似函数,从而将问题转化为一个多元单目标优化问题,最后运用粒子群优化算法求解该优化问题,由此求得二阶线性常微分方程的两点边值问题的近似解.数值实验表明该方法优于传统的里兹法和有限差分方法.

一类二阶线性常微分方程两点边值问题的数值解

采用有限差分法,将一类二阶线性常微分方程两点边值问题转化为绝对值方程,并给出了一个迭代算法,证明了算法的收敛性.数值实验结果表明,该方法迭代次数少、精度高.

分数阶常微分方程初值问题的高阶近似

对于整数阶常微分方程的数值解法,如欧拉法、线性多步法等都已有较完善的理论.而对于分数阶微分方程数值方法和误差估计的理论研究相对较少.在这篇文章中,我们考虑最简单的分数阶常微分方程,引进了分数阶的线性多步法,导出了分数阶常微分方程初值问题的高阶近似,证明了其方法的相容性和收敛性,并且给出了稳定性分析.最后给出了一些数值例子,证实了这个分数阶线性多步法是解分数阶常微分方程的一个有效方法.

电弧螺旋不稳定性研究中一类二阶线性常微分方程的解法

对电弧螺旋不稳定性理论研究中所遇到的一类二阶线性常微分方程，采用级数解法，给出了适宜计算机迭代计算的解析表达式。

二阶齐次线性微分方程的边值问题的解的相似结构

通过对二阶齐次线性微分方程边值问题的解析表达式进行整理和简化,得到了解式的相似结构形式;说明了该类微分方程的解,具有类似于实数可表为连分式,图形具有相似性的所谓式相似性质;指出了解式的相似性质的研究,有利于进一步地分析解的内在规律,解决相应的应用问题,方便编写相应的分析软件;它是微分方程理论的新发展。