非线性Kirchhoff型波动方程全局吸引子的存在性

非线性Kirchhoff型波动方程描述了竖直方向上的波动.利用近似FaedoGalerkin的方法通过先验估计和一种新的验证紧性的方法(条件C)讨论了这类波动方程强解的全局吸引子.     

考虑非傅立叶效应的瞬态导热过程的波动响应分析

瞬态导热分析需要考虑非傅立叶效应.通过对抛物型及双曲型热传导方程,以及耦合热传导方程后的波动方程的数值求解,研究了非傅立叶效应下导热过程中的波动响应.结果表明,双曲型热传导过程具有明显的波动特性,所引起的波动响应前沿值成倍提高,且呈现显著的跃变行为,而波动峰值外的部位围绕着初始值小幅波动.     

基于Gristensen算法的砂岩储层横波速度计算方法

由于横波测量成本高,大部分油田测井资料中仅有少部分横波数据,则依据常规测井资料准确构建横波曲线已成为关键.考虑到横波构建理论方法更多地依赖实验室分析资料,提出在Gristensen经验公式基础上,以研究区横波测量曲线为约束,通过优化反演确立公式系数是一种好的研究思路.优化方法实现中采用阻尼型高斯牛顿法,保障了多参数优化迭代的收敛性和精度.将研究方法用于卫星油田横波数据构建中,取得好的计算结果.     

一般非自治单种群Kolmgorov时滞生态系统的持久性准则及其应用

本文研究一般非自治单种群Kolmgorov时滞生态系统．关于种群的持久性和系统的正周期解的存在性的充分条件被建立,作为这些准则的应用，一系列特殊的单种群增长的时滞系统被研究．关于种群的持久性和系统的正周期解的存在性的一系列具体的判别准则被建立．     

On the stability of two new two-step explicit methods for the numerical integration of second order initial value problem on a variable mesh

We present two novel two-step explicit methods for the numerical solution of the second order initial value problem on a variable mesh. In the case of a constant mesh the method is superstable in the sense of Chawla (1985). Numerical experimentation is provided to verify the stability analysis.     

Influence of moving magnetic field on three dimensional Couette flow

A three dimensional steady fully developed MHD Couette flow of a viscous incompressible electrically conducting fluid is analysed. The lower stationary porous plate is subjected to a periodic injection velocity and the upper porous plate in uniform motion to a constant suction velocity. A magnetic field of uniform strength applied normal to the planes of the plates is fixed with the moving plate. Neglecting the induced magnetic field, an approximate solution for the flow field is obtained and discussed with the help of graphs.     

REMARKS ON THE LIFESPAN FOR THE SOLUTION TO NONLINEAR WAVE EQUATIONS IN THREE SPACE DIMENSIONS

The authors consider the Cauchy problem for the following nonlinear wave equationswhere x ∈ R3, t ≥ 0, ε > 0 is a small parameter, and obtain the sharp bounds for the lifespan of solution to (0.1). Specially, it is proved that there exist two constants C1 and C2, which are independent of ε, then the lifespan T(ε) satisfies the folowing inequalities     

Etude de la restauration de l'aluminium irradié aux electrons (Etape III)

The nature of the electron bombarded aluminium electrical recovery process has been studied by combining quenches with irradiations. Measured Frenkel pair formation rates per incident electrons as well as annealing kinetics emphasize the role of impurity interstitial trapping.