查询词典 finite difference approximation

The generalized Douglas scheme for variable coefficients is applied to wide-angle multistep finite-difference beam propagation method.

交叉波导是集成光学中一种重要的器件单元，它的应用包括制作能量分配器、光开关[1] 、低损耗低串音的交叉光路网络等。

At the end of this paper, perpendicular design calculation of non -linear finite element method is used to evaluate slope reliability. The results are compared with those of Monte-Carlo method, Their difference is small.

提出了非线性有限元法的正交设计计算用于评价边坡工程的可靠性，将其结果与Monte—Carlo计算结果进行了详细比较，二者具有很好的一致性。

The quadrupolar ring's temperature field is studied numerically by finite difference method, its null drift is analyzed at given temperature circumitance.

通过有限差分法，对光纤环的Shupe效应作了研究，对四极子光纤环在非稳态传热的过程中的温度场进行数值求解，分析了光纤环在试验提供的温度环境下的温度零漂。

A general Godunov finite difference schemes-WENO (Weighted Essentially Non-Oscillatory) schemes which have fifth-order accuracy is used to perform a numerical calculation for 2-dimensional axis symmetrical laser-supported plasma flow field under laser ablated solid target.

采用具有五阶精度的WENO差分格式和简易等离子体状态方程模型对激光与等离子体相互作用的复杂物理过程进行了数值计算，分析了激光束能量在等离子体区中的吸收、屏蔽效应等动态耦合规律以及激光支持等离子体前驱冲击波传播。

A general Godunov finite difference schemes-WENO schemes which had fifth-order accuracy was used to make a numerical calculation for 2-dimensional axis symmetrical laser-supported plasma flow field under laser ablated solid target and laser ablated propulsion efficiency parameters(mechanical coupling coefficient etc.) was obtained by the simulation.The models of the calculation of ionization degree of plasma and the interaction between laser beam and plasma and the simplified eos of plasma were considered in the simulation.

采用针对高温气体电离度的一种近似计算方法，以及具有五阶精度的广义Godunov差分格式-加权本质无振荡格式WENO(weighted essentially non-oscillatory schemes)，给出了高温气体状态方程的简便描述，并考虑激光与等离子体的相互作用，模拟了强激光与固体靶相互作用时激光支持靶面等离子体流场的动态物理过程，并给出了不同参数条件下激光烧蚀固体靶的推进效应参数。

According to fully implicit method, seepage model of low-permeability fractured gas reservoirs are discretized with finite difference method, and corresponding numerical model, coefficient matrix and matrix element are obtained; then based on modern software engineering, numerical simulation software was correspondingly developed with Fortran95 programming language

按照全隐式离散化方法，采用有限差分方法对低渗裂缝性气藏渗流数学模型进行了离散，得到了相应的数值模型、系数矩阵和矩阵元素。然后基于现代软件工程的基本思想，用Fortran95语言开发了相应的数值模拟软件

This thesis is divided into six parts. The first chapter is preface, the current status of research in the inverse problems for parabolic partial differential equations is reported; the second chapter is "regularization methods for numerical differentiation and their applications ", in this chapter we investigate many regularization methods from a viewpoint of regularization theory and algorithm, some applications in the inverse problems for parabolic partial differential equations are given; the third chapter is "spectral regularization methods". Based on Fourier analysis, within the framework of regularization theory, we apply the spectral methods to some ill-posed problems. Many numerical experiments are done in order to show the validity of the methods; the fourth chapter is devoted to wavelet dual least squares method and a revised wavelet method; in the fifth chapter,we combine finite difference method with method of lines and apply it to the backward heat conduction problem in time; in the sixth chapter "identification problems for unknown source ", the essence and the degree of two problems related to source identification are pointed out, at the same time, some numerical methods are reported.

本文分为六个部分，第一章前言简要分析了国内外抛物型偏微分方程反问题的研究现状；第二章数值微分的正则化及其应用从正则化理论和算法的角度出发，考察了许多正则化方法，还给出了数值微分在抛物型偏微分方程反问题的一些应用；第三章谱正则化方法是在Fourier分析的基础上，在一般正则化理论的框架下，给出了这种方法在各种不适定问题中的应用，数值实验表明谱方法是有效的；第四章研究了小波对偶最小二乘方法和改进的小波方法；第五章主要研究了有限差分方法结合线方法在时间反向热传导问题中的应用；第六章是未知源识别问题，主要指出了两类未知源问题的不适定程度和不适定本质，同时报告了一些数值方法。

The principles of FEM, finite difference method , numerical mode method and integral equation method are elaborately described.

详细阐述了非均匀介质问题中常用的有限元法、有限差分法、数值模式匹配法和积分方程方法的基本原理和各自的优缺点。

The numerical solution of the model is based on an energy-conservation scheme of finite difference.

模式的数值解满足一套能量守恒的有限差分格式。

First, the finite difference was used to solve numerically the coupled Navier-Stokes equation and the convective-diffusion equation for surfactant in a orthogonal body-fitted coordinate system. The effect of surfactant on the flow field inside and around the deformed drop was successfully simulated.

本文在正交贴体坐标系下采用有限差分方法，对不可压缩流体的Navier-Stokes方程和表面活性剂的对流—扩散方程耦合求解，从而首先模拟了表面活性剂对单液滴运动的影响。

A strange and mysterious deep sea creature.

一种奇异、神秘的深海生物。

It's a yellow rectangle .

这是黄色的长方形。