数值微分

Firstly, the isotropic difference templates were introduced to approximate the differential in the ADI-FDTD method, and the weighting coefficients of difference terms were determined for implementing isotropic numerical dispersion; Then the permittivity and permeability were adjusted manually to reduce the numerical dispersion error in any directions. Therefore the simulation accuracy and efficiency can be improved effectively for time domain problems with some finite bandwidths.

该方法在ADI-FDTD方法的差分近似微分中引入各向同性差分模板，并通过确定各向同性差分的加权系数来近似实现各向同性，然后人为修正空间的介质参数来减少各个方向上的数值色散误差，因此在模拟一定带宽的时域问题时可有效提高计算精度和计算效率。

In this paper, based on the Bessel function, an Ordinary Differential Equation was derived for time-domain Green function and its gradients in this paper. A new efficient calculation method based on solving ODE is proposed.

在探索求解精度和计算效率的矛盾中，提出了结合求解常微分方程的节点制表、节点间插值的快速计算Gre en函数的方法并据此开发了一套三维深水时域Green函数的数值计算程序。

The grid generation technique for body_fitted coordinate system by means of numerical solution of biharmonic equations is studied, then the topical H_type grid and the flow field is generated and simulated numerically, respectively.

本文对利用双调和方程微分法生成贴体坐标网格的技术进行了探讨和尝试，生成了典型的H型网格，并对流场进行了数值模拟。

Routh-Hurwitz is used to determine that the characteristic equation has negative real root, and Center-Manifold theorem is used to study the stability of autonomous differential system in the case of hyperbolic and non-hyperbolic at the equilibrium point.

利用Routh-Hurwitz判定特征方程有负实部根，并利用中心流形定理研究了自治微分系统在平衡点处双曲和非双曲情况下的稳定性，由此产生系统趋于不同稳定点时病毒分裂的临界值，同时利用数值模拟验证了分析的合理性。

The Computation Fluid Dynamics solute a group of differential coefficient equation on mass,energy,momentum,user-defined scalar quantity by numerical value method ,and the solution can predict the detail of the flowing process.It have been the tool to optimize the process set or magnify the fix quantity design .

计算流体力学的原理是用数值方法求解非线性联立的质量、能量、动量和自定义的标量的微分方程组，求解结果能预报流动过程的细节，并成为过程装置优化和放大定量设计的有力工具。

Conditional stability.

反问题，边值问题，不适定问题，偏微分方程，积分方程，条件稳定性，数值分析

On the basis of similarity principle study of the ASP ternary complex flooding, we adopt the method of simplicity, take the foam into differential equation, construct the similarity criterion and the similarity principle of differential conditions, the similarity criterion and the similarity principle are checked and analyzed by numerical simulation and physical simulation method.

在三元复合驱相似原理研究的基础上，采用简化的方法，将泡沫相引入微分方程，建立了泡沫复合驱物理模拟全相似准数及不同条件下的相似准则，并利用数值模拟方法、物理模拟方法对准则进行了检验和敏感性分析。

Based on the equilibrium equation of an arch element the cubic nonlinear dynamic model with second order is established and the nonlinear differential dynamic system without constant term is obtained through a transfer process of T=U+b. Hence three fixed points and the homoclinic orbits are found. The critical condition of the chaotic vibration of the elastic arch is given by using the method of Melnikov function. The numerical results of the stationary and chaotic motion are given and discussed.

首先利用拱的单元平衡方程建立了拱的二阶三次非线性动力学模型；然后通过变换使方程转化为不含常数项的非线性微分动力系统，并由此得到无扰动系统的3个不动点与同宿轨道；再用Melnikov函数法给出了发生混沌的临界条件；最后给出了该系统出现定常运动和混沌运动的数值结果。

A numerical simulation to the whole motion differential equation is finished, and a continuous angular displacement curve of micro reflectmirror is obtained.

通过对该模型的完整机电动力学微分方程数值求解所作的运动仿真，得到了微镜基板的连续角位移曲线，表明该装置具有良好的光束稳定特性

A curve coordinate system is established in which the original problem may be reduced to a fixed boundary problem over a rectangular region and thus may be solved by difference methods .

给出了一种用曲线坐标求解椭圆型偏微分方程自由边值问题的数值解法；该方法通过引入两个辅助问题，它们构成一个曲线坐标系。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。