离散

We show a multi-symplectic scheme for the equations by the multi-symplectic Euler method. The truncation error of its local discrete energy conservation law is also exhibited.

用多辛Euler方法离散此方程组得到了它的多辛格式，并且推导了它的局部能量守恒律的离散误差。

In the PFD, both the differentials and non-differential terms in the differential equation are discretized, and the coefficients of the power series are determined by means of eliminating the truncation error of the corresponding modified scheme, then the high accurate difference scheme is obtained.

摄动有限差分方法在微分方程的差分近似中，离散微商项的同时，也离散非微商项，把非微商项摄动展开成网格步长△x的幂级数，并通过提高差分格式相应修正微分方程误差阶的方法求出摄动幂级数系数，从而获得高精度差分格式。

Based on Crank-Nicoson's technique, and a new approach for the numerical simulation of the model is raised. The truncation error of the one step difference method reaches O (△t^2+△x^2) and of quite good stability condition.

基于Coriolis加速度和Lagrangian应力公式，利用Newton第二定律导出轴向加速度运动弦线横向振动的动力学模型；通过线性变换将方程化为一阶无量纲的非线性微分方程组；并利用Crank-Nicoson的中点离散技巧，给出运动方程的单步二阶差分方法；算法把对运动方程和本构方程分别离散，使之可以用于不同本构的运动弦线的数值仿真。

This method bases on distance transformation in Euclidean metric with the computational complexity of O(2+kn,and is the same with non-Euclidean metric space.

基于欧氏空间中离散点集的2阶V图距离变换原理，论述了栅格形式下离散点集和一般点集图形的2阶V图生成的方法，确定了它的时间复杂性为O(2+kn，适用于欧氏及非欧度量空间的自然图形2阶V图构造。

Interval slope method is proposed for a class of unconstrained min-max-min problems, in which the objective functions are factorable functions. An interval algorithm is given by interval slope discard tests and interval extension of objective functions. Numerical results are also presented.

讨论目标函数为因子函数的离散无约束min-max-min问题，利用区间斜率，构造目标函数的区间扩张和区问斜率删除原则，建立了求解离散无约束min-max-min问题的区间斜率算法，并给出了数值算例。

The outflow fields of a simplified fastback car were studied with numerical methods of different turbulence models and diflerent discretization scheme s with the CFD code STARCD.

以简化的直背式轿车模型为研究对象，以商用计算流体力学软件STAR-CD为工具，应用不同的湍流模型和离散格式对轿车外流场进行了数值模拟，通过与试验结果的对比，研究了湍流模型和离散格式对直背式轿车外流场数值计算精度的影响，同时对SIMPLE算法及其两种修正方法PISO和SIMPISO算法的计算精度进行了比较。

This model used the finite—difference approximation to the advection— dispersion equation. The spatial derivatives in the flow equation are approximated by central difference written about grid—block boundaries and time derivatives are approximated by a fully implicit backward scheme.

水流方程的空间导数采用中心差分格式离散，时间导数采用隐式差分格式离散，建立了土壤水分和污染物在各种饱和度的条件下迁移转化方程耦合求解的二维数值计算模型。

A new scheme for approximating the solution of 2D Maxwell's equations-the high order symplectic scheme is proposed to overcome the shortcoming of the conventional finite difference time domain. The scheme is obtained by discretizing the Maxwell's equations in time domain based on symplectic scheme with high order, and then evaluating the equation in spatial domain with second or fourth order finite difference approximation.

为克服标准时域有限差分方法的缺陷，引入一种新的数值计算方法－高阶辛算法求解Maxwell方程，即在时间上用高阶辛差分格式离散，空间分别采用二阶及四阶精度的差分格式离散。

As we know, the resulting algebraic equations are large systems of non-linear equations with the expanded mixed finite element method for the equation.

用扩张混合有限元方法对其进行离散是常用的方法，其离散化所获得的代数方程组是一很大的非线性方程组。

The approach of computational simulation is the finite element method.The whole research is combined by the following three parts. In part one, a program on quadtree method is compiled. It can automatically generate planar structures with all-quadrangular, good quality elements in high speed, and it can create data files on information of elements and nodes, which provide the foundation for finite element analysis. In part two, a program on finite element calculation is compiled by object-oriented method, During the simulation of fracture, the displacement and stress are calculated by the program.

本文的工作可分为三大部分：第一部分编制了四叉树法程序，通过它可对平面结构进行单元离散，快速自动生成质量较好的全四边形单元，并获得离散后的单元信息和节点信息，为有限元计算打下基础；第二部分利用面向对象方法编制了有限元计算程序，在破坏模拟过程中，利用它进行位移、应力分析；第三部分对脆性材料的破坏过程进行了模拟。

For a big chunk of credit-card losses; the number of filings (and thus charge-off rates) would be rising again, whether

年美国个人破产法的一个改动使得破产登记急速下降，而后引起了信用卡大规模的亏损。

Eph. 4:23 And that you be renewed in the spirit of your mind

弗四23 而在你们心思的灵里得以更新