查询词典 difference equation

Based on the Boltzmann equation,taking the silicon film as example,the temperature effects on the heat capacity of carrier and lattice,thermal conductivity,relaxation time have been studied with the finite difference method.

基于Boltzmann方程，采用了Chen J K等人建立的自相关模型，考虑了Si薄膜的热容、热导率、弛豫时间等热力学参量随温度非线性变化的影响。

The thesis is organized as follows:In Chapter 1,a new partial differential equation model for Spontaneous Potential log in heterogeneous formations is introduced.At the same time,the existence and uniqueness of weak solution to the problem are proved,and the problem of resistance identification in SP log is studied.Furthermore,a jump condition capturing finite difference scheme is proposed and applied to solve such elliptic interface problems.The effects of various factors on SP response,which include objective layers resistivity,bed thickness,bore-hole diameter,invasion and water-flooded zones and so on,are investigated quantitatively by the proposed method, and satisfactory results are obtained.

具体安排如下：第一章首先建立复杂地层中自然电位测井的偏微分方程数学模型，证明了该边值问题弱解的存在唯一性，在此基础上研究了自然电位测井电阻率识别问题：然后发展了用于求解椭圆交界面问题的间断捕捉有限差分方法，利用该方法定量分析了目的层电阻率、地层厚度、井径、侵入带和水淹层等因素对自然电位测井响应的影响，取得了满意的结果。

Compared with Finite Element Method and Finite Difference Method, Boundary Integral Equation Method is computationally more efficient.

与有限元法和有限差分法相比，该方法具有更高的计算效率。

Preserved-amplitude migration ; One-way wave equation ; Fourier finite difference ; Migration operator ; Boundary conditions ; Imaging conditions

保幅偏移；单程波方程；傅里叶有限差分；偏移算子；边界条件；成像条件

By discussing the position hypothesis of fractional-dimension derivative about general function and the formula form the hypothesis of fractional-dimension derivative about power function, the concrete equation formulas of fractional-dimension derivative, differential and integral are described distinctly further, and the difference between the fractional-dimension derivative and the fractional-order derivative are given too. Subsequently, the concrete forms of measure calculation equations of self-similar fractal obtaining by based on the definition of form in fractional-dimension calculus about general fractal measure are discussed again, and the differences with Hausdorff measure method or the covering method at present are given. By applying the measure calculation equations, the measure of self-similar fractals which include middle-third Cantor set, Koch curve, Sierpinski gasket and orthogonal cross star are calculated and analyzed.

通过讨论一般函数的分维导数的位置假设及幂函数的分维导数的形式假设，进一步明晰了幂函数的分维导数、分维微分及分维积分的具体方程形式，给出分维导数与分数阶导数的区别，随后讨论了基于一般分形测度的分维微积分形式定义导出的自相似分形的测度计算方程具体形式，给出了其与目前 Hausdorff 测度方法的区别，并对包括三分 Cantor 集合、 Koch 曲线、 Sierpinski 垫片及正交十字星形等自相似分形在内的测度进行了计算分析。

Numerical simulations of the three dimension viscous flow over the SUBOFF-1 model provided by DARPA and other two models are processed by solving RANS equations withκ-εtwo-equation turbulence model and finite volume method, and with SIMPLEC method for pressure-linked terms, central difference shemes for temporal derivative terms, and second-order upwind schemes for convective and diffusive terms.

本文基于RANS方程，采用κ-ε两方程湍流模型来封闭控制方程，采用有限体积法离散控制方程，对于速度压力关联方程，应用协调一致的SIMPLEC算法求解，变化率项用中心差分，对流扩散项采用二阶迎风格式，分别对DARPA提出的裸艇体SUBOFF-1模型以及另外两种回转体模型进行了数值模拟计算。

The central difference explicit scheme based on the dynamic equation can get good results.

而采用基於动力学方程的中心差分显式积分方法可以得到良好的数值结果。

Absorbing boundary condition ; wave equation ; spectral element ; central difference method

吸收边界条件；波动方程；谱元；中心差分法

The model is applied to numerically analyze the wave field and the coastwise current formed by the breaking of oblique incident wave in the Leadbetter Beach, Santa Barbara, California, USA. In the analysis the Crank-Nicolson scheme is adopted to solve the parabolic mild slope equation and the ADI finite difference scheme is applied to solve the model of wave induced coastwise current.

运用该近岸流方程，对美国Santa Barbara Leadbetter海岸波浪斜向入射所产生的波浪场及波浪破碎所形成的沿岸流进了数值模拟，其中抛物型缓坡模型采用Crank-Nicolson格式进行数值离散，近岸流方程采用ADI差分格式离散。

First of all,we construct a semidiscrete finite difference scheme to Burgers equation with initial condition and Dirichret boundary conditions.

首先，对Burgers方程的初边值问题建立了一个半离散的有限差分格式。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。