差分系数

In the light of the complex, high-level and non-linear feature of the mathematical model which describe the transport of the coalbed methane, this paper study the fully-implicit solving method of the mathematical model in detail. Based on the complexity of the algebraic equations which are formed eventually, according to the alternating direction implicit difference pattern, this paper use the iterative method and the fully main element Gauss-Jordan eliminating method to solve equations, which is to use the iterative method to determine coefficient matrix and use the fully main element Gauss-Jordan method to solve th linear algebraic equation group, at the same time of studying the solving method of the mathematical model, according to the devising requirement of FORTRAN77 program structure, this paper draw up computer program and form the corresponding computer model, and verify the validity and reliability of the model in theory by operating the model.

重点研究了模型内、外边界及有关参数的处理，针对描述煤层甲烷运移的数学模型是一个复杂、高阶非线性数学模型的特点，详细研究了模型的全隐式求解方法，根据最后形成的代数方程组的复杂性，按交替方向隐式差分格式，采用迭代与全选主元高斯约当消去法相结合的方法求解方程：即确定系数矩阵采用迭代法，求解线性方程组时采用全选主元高斯约当消去法，在研究模型解法的同时按FORTRAN结构化程序设计的要求，编制计算机程序，形成相应的CBMRS计算机模型，并通过模型的运行从理论上证明了模型的正确性与可靠性。

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。

Majority of the problems researched by them were confined to the difference equations with positive variable or constant coefficient.

但大部分讨论的都是确定方程中变系数为正、或常系数的差分方程问题。

Using the apparatus of high stress and high hydraulic pressure developed by author, a series of tests was carried out, and the expressions of dewater consolidated settlement with hydraulic pressure and coefficient of permeability with efficient stress was obtained.

通过自行设计的高应力、高水压试验装置，进行了一系列的试验，获得了疏排水沉降量与水压变化、渗透系数与有效应力之间的关系表达式；首次对回归系数的主要影响因素从颗粒级配的特征粒径和特性参数入手，进行了系统的分析；得到了压缩模量与水压降的正相关关系式；提出了一种简便、易行的先期固结压力的确定方法，并对深土力学特性进行了初步研究；推导了各种边界条件下Terzaghi 和Biot 固结理论的水头及沉降量的解析解或半解析解；编写了隐式差分

Based on the existed approaches of hydrometeor classification and the requirement of application in China,we construct a algorithm to classify the precipitation particles with the polarimetric radar observations,and make a comparison of polarimetric radar variables sensitivity Z_DR,K_DPand ρ_HV(0) in this model.

在综合分析国内外降水粒子相态识别方法的基础上，结合我国双线偏振雷达的应用需求，建立了一套利用双线偏振雷达探测资料识别降水粒子类型的识别模式，并根据美国KOUN雷达观测资料对该模式进行了分析验证，同时检验了模式中的几个偏振参数：差分反射率因子ZDR、差传播相移KDP、水平偏振和垂直偏振回波功率零滞后互相关系数ρHV(0)对不同降水粒子的识别效果。

Based on Wu's elimination method and "divide-and-conquer" strategy, the undetermined coefficient method for constructing polynomial conservation laws of nonlinear differential-difference equations was improved. Furthermore, a Maple package CLawDDEs was developed to automatically derive conserved densities and associated fluxes of polynomial differential-difference equations.

基于吴消元法和"分治"策略，改进了基于标度不变性构造非线性微分差分方程多项式形式守恒律的待定系数算法，并在计算机代数系统Maple上实现了改进后的算法，其中的软件包CLawDDEs可自动推导出微分差分方程的守恒密度及连带流。

It indicates that simulation results by Z transform method are closer to analytical values than recursion convolution algorithm.

结果表明，Z变换算法的模拟结果比卷积分更接近理论值，标签时域有限差分 Z变换磁化等离子体反射系数透射系数 FDTD method Z transform Magnetized plasma Reflection coefficient Transmission coefficient

This one-way wave equation fits eikonal equation and transport equation corresponding to full acoustic wave equation in travel-time and first order amplitude. According to the perturbation theory often used in inverse solution, we split the velocity field into intraformational constant velocity background and variable velocity disturbance. Then we calculate time-shift quantity of migration and amplitude correction coefficients for wavefield depth continuation in total uniform formation and each formation.

基于反问题求解中常用的摄动理论，把速度场分裂为层内常速背景和变速扰动，求得整个均匀层波场深度延拓的偏移时移量及振幅校正系数、各层的偏移时移量及振幅校正系数，从而得到一个基于傅里叶有限差分法的双域保幅叠前深度偏移算子方程。

An 1-D sediment mathematic model is developed in the second part. Techniques are suggested for some problems in calculations, such as the effective suspended load carrying capacity of the different bed material reach, the coefficient of suspended load carrying capacity, the recovering coefficient of the carrying capacity, the thickness of the mixed layer, the transport width of the bedload, bifurcation and confluence of main and branch channel, and the distribution of deposition and erosion along the cross section, etc. The numerical scheme of 1-D model is induced.

第二部分建立了一维泥沙数学模型，对计算中的几个关键问题提出了处理方法，如不同床沙组成河段的有效挟沙力、挟沙力系数、挟沙力的恢复饱和系数、床面混合层厚度、推移质输移带宽度、干支流入汇及分流问题、横断面冲淤形态及断面修正方法，导出了一维模型的差分格式。

Wideangle parabolic approximations to wave equation usually lead to nonconstant differential migrators with their coefficients varying with lateral velocity variations, and hence require a finitedifference numerical implementation.

波动方程宽角抛物逼近得到的通常是非常系数的单程波传播算子，其系数是速度横向变化的函数，因此需要利用有限差分进行数值实施。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。