具有偏差变元的广义二阶Rayleigh型中立微分方程的周期解

研究了一类具有多个偏差变元的广义二阶Rayleigh型中立微分方程的周期解.通过利用重合度理论和不等式分析技巧,获得了方程周期解存在性新的充分条件,推广和改进了早期文献的相关结果.最后,给出一个例子,说明所得结果的可行性.     

一类二阶常微分方程初值问题的无穷多解性

应用分离变量法,得到了一类二阶微分方程初值问题存在无穷多个非负解的充分必要条件,并给出了所有的无穷多个非负解．。     

一类多偏差变元的二阶微分方程周期解问题

作者利用重合度原理研究了一类多偏差变元的二阶微分方程■周期解问题.得到了有关周期解存在性的新的结果     

一类二阶非线性阻尼微分方程解的渐近性质

研究了一类二阶非线性阻尼微分方程非振动解的渐近性质,建立了三个渐近性定理.     

一类二阶具偏差变元中立型泛函微分方程周期解的存在性

本文研究了一类二阶具偏差变元的中立型泛函微分方程周期解的存在性问题.利用J.Mawhin重合度拓展定理,得到了关于中立型泛函微分方程周期解存在的结果.     

Hilbert空间中的二阶微分方程问题

运用多值分析、单调算子理论和Schauder不动点定理讨论了一类具有多点边值条件的二阶微分包含问题．作为一个预备性的结果，给出了一类二阶发展方程的解的存在唯一性和对初值的连续依赖性．最后，给出了以上结论在最优化和偏微分方程方面的两个应用．     

一类中立型退化时滞微分方程的周期解

讨论了一类中立型退化时滞微分方程的周期解的存在条件,并且给出了二维退化滞后微分方程的周期解的存在性问题,且给出了一个充要条件和两个充分条件,最后举例说明结论的有效性。     

可逆系统的KAM定理的一个应用

本文利用可逆系统的KAM定理证明了一类既不保守也不耗散的二阶非线性微分方程解的有界性、不变环面和拟周期解以及次调和解的存在性。     

一类非齐次时滞微分方程概周期解的存在性

该文研究一类非齐次时滞微分方程的概周期解, 结合运用指数二分法, 给出了系统存在概周期解的一组充分条件.     

一类非齐次时滞微分方程概周期解的存在性

该文研究一类非齐次时滞微分方程的概周期解，结合运用指数二分法，给出了系统存在概周期解的一组充分条件．     

Multiple periodic solutions for Hamiltonian systems with not coercive potential

Under an appropriate oscillating behavior of the nonlinear term, the existence of infinitely many periodic solutions for a class of second order Hamiltonian systems is established. Moreover, the existence of two non-trivial periodic solutions for Hamiltonian systems with not coercive potential is obtained, and the existence of three periodic solutions for Hamiltonian systems with coercive potential is pointed out. The approach is based on critical point theorems.     

Steady-state and Hopf bifurcations in the Langford ODE and PDE systems

This paper is concerned with the Langford ODE and PDE systems. For the Langford ODE system, the existence of steady-state solutions is firstly obtained by Lyapunov–Schmidt method, and the stability and bifurcation direction of periodic solutions are established. Then for the Langford PDE system, the steady-state bifurcations from simple and double eigenvalues are intensively studied. The techniques of space decomposition and implicit function theorem are adopted to deal with the case of double eigenvalue. Finally, by the center manifold theory and the normal form method, the direction of Hopf bifurcation and the stability of spatially homogeneous and inhomogeneous periodic solutions for the PDE system are investigated.     

二阶离散Hamiltonian系统的多重周期解

利用变分原理和Clark定理,研究了带参数的二阶离散Hamiltonian系统的多重周期解,得到了此类方程周期解个数的下界估计.     

Periodic solutions for some second order systems

In this paper, we use the Minimax Theorem to investigate periodic solutions of some second order systems, and give some sufficient conditions for the existence for periodic solutions. The results generalize and improve some known results.     

Periodic solutions for sublinear systems via variational approach

The variational method is used to obtain some existence theorems for periodic solutions of second order systems with or without impulsive under weak sublinear growth conditions.     

Periodic solutions for second order Hamiltonian systems with a change sign potential

An existence theorem is obtained for periodic solutions of nonautonomous second order Hamiltonian systems with a change sign potential by the minimax methods in critical point theory.     

Notes on periodic solutions of subquadratic second order systems

Some existence theorems are obtained for periodic solutions of the subquadratic second order systems by the minimax methods in critical point theory.     

Almost Periodic Solutions of Nonlinear Second Order Differential Equations

We provide existence results for almost periodic solutions of nonlinear second order ordinary differential equations. The results extend existence results for periodic solutions of periodic equations, where the existence of periodic sub and supersolutions implied the existence of periodic solutions.     

Periodic solutions for some nonautonomous second order Hamiltonian systems

The existence and multiplicity of periodic solutions are obtained for nonautonomous second order Hamiltonian systems by the minimax methods in critical point theory.     

Some existence results on periodic and generalized periodic solutions for singular hamiltonian systems

In this paper, we use the variational method to study the existence of periodic and generalized periodic solutions of planar second order Hamiltonian systems when a singular potential is present. The results obtained are applied to the study of generalized periodic solutions of the Restricted Three-Body Problem and the Planarn-Body Problem.