OSCILLATION OF SECOND-ORDER NEUTRAL DYNAMIC FUNCTIONAL EQUATIONS

In this paper we establish some oscillation criteria for the second-order neutral dynamic delay equations on time scales. By using the generalized Riccati technique, new oscillation criteria are obtained.     

Doubly Perturbed Neutral Stochastic Functional Equations Driven by Fractional Brownian Motion

In this paper, we study a class of doubly perturbed neutral stochastic functional equations driven by fractional Brownian motion. Under some non-Lipschitz conditions, we will prove the existence and uniqueness of the solution to these equations by providing a semimartingale approximation of a fractional stochastic integration.     

广义中立型Emden-Fowler时滞阻尼微分方程的振动性

研究了一类具有阻尼项的广义中立型Emden-Fowler时滞微分方程的振动性.利用Riccati变换、积分平均技巧等方法,获得了该方程解振动的充分条件,所得结果推广和改进了最近研究中的一些结果.     

HL-2A中性束大功率离子源的研制

2007年3月, 为HL-2A中性束注入器研制的大功率离子源在核工业西南物理研究院成功通过了测试. 该离子源为圆柱结构的桶式离子源型; 加速器采用三电极的加减速系统. 实验运行参数如下: 灯丝加热电流1100A, 电压12V, 弧放电电压120V, 弧放电电流1050A, 等离子体密度达2.5×10¹²/cm³, 离子流密度0.44A/cm²; 在距等离子体电极5mm的平面上, 等离子体的均匀性好于5%, 工作脉宽2s. 离子源物理设计、工程考虑、实验研究结果等将在本文介绍.     

基于物理中面FGM中厚板自由振动的有限元分析

基于物理中面和一阶剪切变形板理论,研究了不同边界条件下功能梯度材料(FGM)中厚板的自由振动问题．假设功能梯度板的材料性质沿厚度方向按幂函数规律连续变化．根据哈密顿原理建立了FGM板有限元形式的自由振动方程,利用MATLAB软件编写程序进行了计算．通过数值算例,讨论了不同边界条件下FGM中厚板的无量纲频率随材料梯度指数和厚宽比的变化情况,并与经典板理论下的频率进行了比较．     

Nonlinear vibration analysis of functionally graded beams considering the influences of the rotary inertia of the cross section and neutral surface position

In the paper work, the nonlinear vibration response of functionally graded (FG) Euler–Bernoulli beam resting on elastic foundation is studied. Based on von Kármán’s geometric nonlinearity, the partial differential governing equations describing the nonlinear vibration of FG Euler–Bernoulli beam are derived from Hamilton’s principle and are reduced to an ordinary nonlinear differential equation with quadratic and cubic nonlinear terms via Galerkin’s procedure. Due to unsymmetrical material variation along the thickness of FG beam, the neutral surface concept is proposed to remove the stretching and bending coupling effect and the rotary inertia of the cross section is incorporated to obtain an analytical solution. Numerical results are presented to show the effects of the nonlocal parameters and vibration amplitude on the frequency responses. This results may be useful in design and engineering applications.     

方程 λ(1+ ce~(-τλ)+a+ be~(-τλ)= 0所有根具有负实部的充要条件

考虑方程     

二阶中立型方程的强迫振动

讨论了一类具有偏差变元的二阶中立型方程,给出了该类方程解振动的充分条件.     

关于中立型时滞模型的周期正解

本文利用拓扑度理论和某些新技巧,研究了一类中立型时滞模型N′(t)=N(t)［a(t)-b(t)N(t-τ(t))-c(t)N′(t-τ(t))］周期正解的存在性,得到了一些新结果,解决了一个公开问题,并推广、改进了一些已知文献的结果,同时也改正了文［3］中微分运算的错误和定理2.     

The method of Lyapunov functionals in stability analysis of functional-differential equations

We develop the method of Lyapunov functionals in the stability analysis of linear nonautonomous functional-differential equations of neutral type. The approach is based on the construction of limit equations and limit Lyapunov functionals. Translated fromMatematicheskie Zametki, Vol. 68, No. 3, pp. 323–331, September, 2000.