有限差分近似法给出合成地震剖面

有限差分近似法对波动方程已经编出了产生合成地震剖面的程序。这里使用的方程与常用的弹性波传播的方程稍有差别,但不是声学上的差别。假定介质是不均匀的,也可能是正交各向异性介质。所采用的座标系统是基于以圆柱轴为对称的圆柱座标系统,即轴是对称的。有限差分法还有一点不同的地方就是它允许在两个方向上使用不均匀的网格点距,而且。

基于星敏感器的载体角速度测定方法研究

提出了一种新的测定航天器角速度矢量的方法。该方法只需得到来自星敏感器的载体矢量测量信息,就可确定载体角速度。提出了基于各种不同差分法的运算规则,表示出了每种近似法的估计误差协方差。仿真结果表明,结合简单的滤波,该方法能够提供非常精确的角速度估计值,而且计算量远比卡尔曼滤波小得多。

电阻抗断层成像中抑制电极移动伪影方法的研究进展

电阻抗断层成像现已被广泛应用于肺功能成像、乳腺癌早期检测以及颅脑功能成像等医学领域,在成像过程中,测量对象边界上的电极产生位置变动,将会引起电阻抗成像算法中模型参数误差,从而导致重构图像产生大量伪影。针对这一问题,本文首先综述了改善此种严重噪声干扰的几种算法,并对这些算法的物理基础进行了简单的介绍,然后,总结现行几种抗电极位置变动干扰的算法原理,对其特点进行总结和评述,并在文章的最后,对几种算法的不足做出分析,对其未来的研究与应用进行了展望。

求压杆稳定的临界力的数学方法

求压杆稳定临界力是个老问题，扩充其方法，采用多种数学方法讨论．

Effects of Pressure Stress Work and Viscous Dissipation in Mixed Convection Flow Along a Vertical Flat Plate

The Effects of pressure stress work and viscous dissipation in mixed convection flow along a vertical fiat plate have been investigated. The results are obtained by transforming the governing system of boundary layer equations into a system of non-dimensional equations and by applying implicit finite difference method together with Newton＇s linearization approximation. Numerical results for different values of pressure stress work parameter, viscous dissipation parameter and Prandtl number have been obtained. The velocity profiles, temperature distributions, skin friction co-efficient and the rate of heat transfer have been presented graphically for the effects of the aforementioned parameters.

Finite Difference Scheme for Solving Parabolic Partial Differential Equations with Random Variable Input under Mean Square Sense

This study deal with seven points finite difference method to find the approximation solutions in the area of mean square calculus solutions for linear random parabolic partial differential equations. Several numerical examples are presented to show the ability and efficiency of this method.