一类复代数微分方程组解的级

本文利用Zalcman引理研究了一类高阶代数微分方程组解的级的问题，将S．Bank和R．Kaufman，G．Garsegian，以及A．A．Gol’dberg等人的有关代数微分方程的一个结果推广至一类微分方程组中．     

时滞微分方程的不共轭性

本文推广了共轭点和不共轭微分方程的概念，证明了时滞微分方程的不共轭区间不可能是一个单点集．此外，还证明了时滞微分方程的不共轭性与边值问题的可解性之间的联系．     

常系数线性微分方程RMI解题机

本文介绍的常系数线性微分方程解题机是利用数学方法论的研究成果，摸拟人的数学思维过程，采用关系映射反演（ＲＭＩ）方法，通过符号推理给出微分方程解析解的数学软件．文中介绍了研制该解题机的基本思想和实现技术，并给出了用解题机求解微分方程和微分方程组的几个实例．     

一类非线性泛函微分方程的渐近性

本文利用单调半流理论研究一类非线性泛函微分方程的渐近性态，发展了ＨｉｒｓｃｈＭ．Ｗ．和ＳｍｉｔｈＨ．Ｌ．关于常微分方程所得的某些结果．     

倒向随机微分方程弱解（英）

引入倒向随机微分方程弱解的概念，应用Girsanov变换，建立了两类倒向随机微分方程（0．1）和（0．2）弱解存在的等价性，由此得到倒向 随机微分方程弱解存在的几个充分条件。     

浅析二阶齐次线性变系数微分方程的一个可积类型

本文讨论了二阶齐次线性变系数微分方程的特殊形式，给出了这种微分方程的一个可积类型．     

全国平均每百户居民私家车拥有量预测

为了对全国平均每百户居民私家车拥有量进行预测，建立了可分离变量微分方程的数学模型，采用最小二乘法，借助Excel作为计算工具，得到了微分方程近似解的参数值，并用微分方程的近似解估计了最大拥有量以及2010年以后某些年的拥有量．     

双曲积分微分方程的有限元方法及其插值后处理技术应用

本文对一类半线性双曲积分微分方程首次应用有限元方法，研究了它的半离散和全离散有限元格式，获得了Ｌ∞（Ｌ２）模意义下的最优误差估计．又对线性双曲积分微分方程利用插值后处理技术获得了Ｌ∞（Ｌ１）模意义下整体超收敛１阶的高精度，而且计算量并未因此增加．本文方法可运用到各类发展型微分及积分微分方程上面．     

Banach空间中非线性脉冲积分微分方程的正解(英)

借助于锥理论，本文讨论Banach空间中非线性脉冲积分微分方程的解．给出一阶脉冲微分方程存在唯一正解的条件及混合型脉冲积分微分方程至少具有两解的条件．     

偏微分方程在图像去噪中的应用

本文介绍用于图像去噪的偏微分模型、方法的发展历程．从理论上分析了线性模型、简单非线性模型、复杂非线性模型、多步处理模型出现的背景和优缺点，并从空域和频域上对偏微分方程模型的去噪原理进行了分析．最后，指出了偏微分方程去噪与小波去噪结合的途径，据此对偏微分方程未来的发展方向进行了展望．     

Output feedback vibration control of a string driven by a nonlinear actuator

In this paper, we design an observer-based output feedback controller to exponentially stabilize a system of nonlinear ordinary differential equation-wave partial differential equation-ordinary differential equation. An observer is designed to estimate the full states of the system using available boundary values of the partial differential equation. The output feedback controller is built via the combination of the ordinary differential equation backstepping which is applied to deal with the nonlinear ordinary differential equation, and the partial differential equation backstepping which is used for the wave partial differential equation-ordinary differential equation. The controller can be applied into vibration suppression of a string-payload system driven by an actuator with nonlinear characteristics. The global exponential stability of all states in the closed-loop system is proved by Lyapunov analysis. The numerical simulation illustrates the states of the actuator, string, payload and the observer errors are fast convergent to zero under the proposed output feedback controller.     

Lipschitzian semigroups and abstract functional differential equations

The paper is devoted to studying an abstract functional differential equation by a nonlinear semigroup approach. We first prove in details the equivalence of the well posedness of an abstract functional differential equation and an associated abstract Cauchy problem in the sense of strong solutions. Secondly, a sufficient condition is derived for well posedness of the abstract functional differential equation. Thirdly, we present principles of linearized stability for the abstract functional differential equation. Finally, the results obtained are applied to a reaction-diffusion equation with delays.     

Periodic solutions of retarded functional differential equations

The classical criterion for the existence of a periodic solution of a forced, linear, retarded functional differential equation (rfde) references the solution of an adjoint equation which is an advanced functional differential equation. This paper introduces a new criterion which does away with the (anti-causal) advanced functional differential equation.     

Almost sure stability for uncertain differential equation

Uncertain differential equation is a type of differential equation driven by Liu process. So far, concepts of stability and stability in mean for uncertain differential equations have been proposed. This paper aims at providing a concept of almost sure stability for uncertain differential equation. A sufficient condition is given for an uncertain differential equation being almost surely stable, and some examples are given to illustrate the effectiveness of the sufficient condition.     

On nonlinear systems consisting of different types of differential equations

We consider a system consisting of a quasilinear parabolic equation and a first order ordinary differential equation where both equations contain functional dependence on the unknown functions. Then we consider a system which consists of a quasilinear parabolic partial differential equation, a first order ordinary differential equation and an elliptic partial differential equation. These systems were motivated by models describing diffusion and transport in porous media with variable porosity. Supported by the Hungarian NFSR under grant OTKA T 049819.     

Riccati微分方程特解新求法的研究

通过对一般Riccati方程进行初等变换,使之变为特殊的Riccati方程,然后利用公式、观察实验,或利用二阶微分方程的特解,或利用一阶微分方程组的特解等方法,求得这些Riccati方程的特解.     

Complex Lie symmetries for scalar second-order ordinary differential equations

A scalar complex ordinary differential equation can be considered as two coupled real partial differential equations, along with the constraint of the Cauchy–Riemann equations, which constitute a system of four equations for two unknown real functions of two real variables. It is shown that the resulting system possesses those real Lie symmetries that are obtained by splitting each complex Lie symmetry of the given complex ordinary differential equation. Further, if we restrict the complex function to be of a single real variable, then the complex ordinary differential equation yields a coupled system of two ordinary differential equations and their invariance can be obtained in a non-trivial way from the invariance of the restricted complex differential equation. Also, the use of a complex Lie symmetry reduces the order of the complex ordinary differential equation (restricted complex ordinary differential equation) by one, which in turn yields a reduction in the order by one of the system of partial differential equations (system of ordinary differential equations). In this paper, for simplicity, we investigate the case of scalar second-order ordinary differential equations. As a consequence, we obtain an extension of the Lie table for second-order equations with two symmetries.     

Quasi-periodic solutions of nonlinear elliptic partial differential equations

In a recent paper [9] the KAM theory has been extended to non-linear partial differential equations, to construct quasi-periodic solutions. In this article this theory is illustrated with three typical examples: an elliptic partial differential equation, an ordinary differential equation and a difference equation related to monotone twist mappings.     

Picard-Vessiot theory for real fields

The existence of a Picard-Vessiot extension for a homogeneous linear differential equation has been established when the differential field over which the equation is defined has an algebraically closed field of constants. In this paper, we prove the existence of a Picard-Vessiot extension for a homogeneous linear differential equation defined over a real differential field K with real closed field of constants. We give an adequate definition of the differential Galois group of a Picard-Vessiot extension of a real differential field with real closed field of constants and we prove a Galois correspondence theorem for such a Picard-Vessiot extension.     

临界状态下一阶时滞微分方程的线性化振动性

本文首先在临界状态下建立了一阶非线性非自治时滞微分方程ｘ＇（ｔ）＋＝１ｐｉｘ（ｔ－Ｔｉ）＋ｆ（ｔ,ｘ（ｔ－σ１（ｔ））…,ｘ（ｔ－σｎ（ｔ））＝０与一个相关的二阶常微分方程振动性等价定理,进而给出了一阶非线性自治微分方程与相应的线性方程振动性等价的充分条件,从而较好地回答了张炳根在文［２］中提出的一个公开问题．