查询词典 implicit difference scheme

This discretization scheme replaced the gradient magnitude with the absolute value of the difference and omitted an item of the original model. The smoothing velocity and effect are affected by these simplifications according to the analyses of this paper.

这个离散格式用差商代替梯度，并略去了原模型的一项，本文通过理论分析发现这些简化影响了平滑的速度和效果。

How to establish the adjoint medel is discussed by using the Gateaux differential of function and the concepts of the adjoint operators in Hibert space. At the same time it is verified that selecting proper finite difference scheme can ensure discrete form remaining the same adjoint r...

文中利用泛函的Gateaux微分和Hilbert空间上伴随算子的概念讨论了连续的伴随模型的建立，并通过选择适当的差分格式离散伴随模型，使其保持连续时的伴随关系，同时给出了水温初始场最优化过程及相应的同化试验数值结果。

The numerical solution of incompressible viscous flow over an aerofoil is obtained by H-type grids and a special difference scheme.

本文用H型网格和特殊的差分格式数值求解了粘性不可压缩叶型绕流。

This section presents two kinds of characteristic schemes, one is the natural use of the usual backward Euler characteristic difference scheme ( [60] ) onto the triangular mesh, the other replaces the backward Euler's method by modified Euler formula to approximate the characteristic differential equation, so that the discretization for characteristic curve can get up to second order accuracy.

本节给出了两种三角形网格上的特征差分格式，第一种是通常的向后Euler型特征差分格式（[60]）在三角形网格上的自然运用，第二种采用§3.3、§3.4的离散思想，使用改进的Euler公式代替向后Euler公式来近似特征微分方程，使其对特征线的离散达到了二阶精度。

Lastly, we study a model of the heat flow cryptosystem base on a linear pseudoparabolic equation. The C-N difference scheme arithmetic of the encryption and decryption problems is designed. Then the numerical simulation is done through computer programming. So by analysing the simulation data we deduce many regularly conclusions on the influence of the key functions to the encryption and decryption operations, which establish the theoretical base for the application of this cryptosystem.

最后，文章研究了一类基于线性伪抛物型方程的热流密码体制模型，设计了加、解密问题的C—N差分算法并通过计算机编程进行了数值模拟，得出了一些不同密钥函数对加、解密作业影响的规律性结论，为该密码体制的现实应用奠定了理论基础。

Improvement of MT migration tomography technology Based on the immanent relationship between tomography purpose and suitable frequency segment selection, we raise an entire frequency segment multi-parameter tomography scheme of MT finite difference migration. We establish a mathematical relationship among apparent electromagnetism reflectance, migration reflectance, background resistivity and the true resistivity distribution. After the introduction of TE/TM mode superpose rate, we carry out the associated resistivity tomography of two polarization mode to adapt the practical data interpolating situation.

大地电磁偏移成像的改进：针对频段选择和成像效果的内在关系，提出全频段、多参数有限差分偏移的解决方案；构建视反射系数、偏移反射系数、背景电阻率与实际电阻率分布的数学关系实现偏移电阻率成像；同时引入TE、TM模式加权因子以实现两个模式的联合偏移电阻率成像，更好的适应解释工作需要。

Not only is the method applied in this paper better to solve the iteration between unsteady convection and conduction and the boundary condition problem, but also is a developmental application on forward and backward difference of windward scheme under unsteady condition.

不仅较好地解决了对流换热和导热的迭代求解和边界条件的处理问题，还将迎风格式的向前和向后差分发展性地应用于非稳态求解过程。

By analyzing the reason of the numerical oscillation phenomenon and computing the temperature field in plate rolling process,it is found that numerical oscillation can be restrained effectively when the heat capacity matrix is lumped by using backward difference scheme.

近年来，许多研究人员采用有限元法分析热轧和淬火等过程中的瞬态温度场。

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。

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。

Chimborazo and Cotopaxi, took me by the hand.

越过琴博腊索山和科托帕克西山。

This car is in a good condition.

这辆车的状况很好。