查询词典 implicit differential equation

In order to determine the solution set of the equation , by the means of meet-irreducible element and irredundant finite meet-decomposition, we first obtain the maximal solutions to the simple equation in the case that b has an irredundant finite meet-decomposition, and then consider the relation between the equation and the equation , based on this, we obtain the maximal solutions to the equation in the case that each element of the matrix B has an irredundant finite meet-decomposition and so determine its solution set completely.

为了确定方程的解集，本文利用交既约元与不可缩短的有限交分解等工具，同样地先求出简单形式的型矩阵方程的所有极大解，然后讨论方程与方程之间的关系，在此基础上，在B的每个元素均有不可缩短的有限交分解的情况下，求出了方程的所有极大解，从而完全确定了方程的解集。

One way is to regard them as the random variables submit to a certain distribution; another is to take them as a random process—— we derive random variables form any of its function's time development, and, the diffusion equation could be partially approached by a equation which is similar to the Ito stochastic integral equation so that the Ito stochastic integral equation is inter-related with the diffusion equation. Therefore, this process could basically reflect the uncertainty in different models.

PSFEM法是假定基本随机变量在均值点处产生微小摄动，利用Taylor级数把随机变量表示为确定部分和由摄动引起的随机部分，从而将有限元控制方程转化为一组线性的递推方程，求解得出位移的统计特性，进而求出应力的统计特性。

The non-isothermal kinetic data were analyzed with the Achar equation, Coats-Redfern equation, Kissinger equation, Flynn-Wall-Ozawa equation and Starink equation.The mechanism function and kinetic parameters of the thermal decomposition in the third step were obtained.The chemical reaction mechanism (F3) controlled the third thermal decomposition process.The apparent activation energy and the pre-exponential factor were 351 kJ·mol-1 and 2.57×10 30s-1 respectively.

采用Achar方程、Coats-Redfern方程、Kissinger方程、Flynn-Wall-Ozawa方程和Starink方程对非等温动力学数据进行了分析，得到了第3步热分解反应的机理函数、动力学参数和热分解反应动力学方程，其热分解反应过程受F3机理控制，表观活化能为351 kJ·mol-1，指前因子为2.57×

First the three-dimensional Hailmuhz equation of magnetotelluric field is split into two 2D equations which could be changed into 1D equation by Fourier transformation method. The two zootomic coefficients of the equation are found out by the derivation of vertical component of electromagnetic field being sufficient the equation and the boundary condition. The resolution of 1D equation can be confirmed.

首先将大地电磁场满足的三维亥姆霍兹方程降维分裂成两个二维响应方程，然后对每一个二维方程进行傅里叶变换，使二维方程变为一维方程，通过大地电磁场垂向方向的导数在地面上所满足的边界条件，确定外推方程中的两个待定系数，从而得到一维外推方程的解。

Spectral element methods for partial differencial equation is introduced in this study from viewpoint of the collocation approximation of Chebyshev polynomial. Wave Equation and its space discretization are deduced. Two time integral methods, central difference method and implicit Newmark method, are introduced, and their stability and applicability are also discussed in some details. The significance of absorbing boundary conditions in spectral element methods for Aeroacoustics is explained, and Clayton-Engquist-Majda absorbing boundary conditions is emphasized and introduced, then the discrete scheme of this boundary conditions is deduced and applied to spectral element methods for wave equation.

本文从Chebyshev多项式逼近理论出发，详细介绍了谱元方法求解偏微分方程的过程；推导了流体中的声波动方程并在空间上对其进行了谱元离散；详细讨论了两种时间积分方法──中心差分法和Newmark方法，分析了它们的稳定性条件，并从理论上对比了两种方法的优缺点和适用范围；将吸收边界条件推广应用于谱元方法求解气动声学问题中，重点介绍了Clayton-Engquist-Majda吸收边界条件的原理和公式，推导了该吸收边界条件的变分形式，并将其引入波动方程的离散形式中。

By introducing the parameter , construct a new kind of weighted implicit difference scheme for (1+1)-dimension nonlinear Sine-Gordon equation and the generalized nonlinear Sine-Gordon equation respectively. Give out an ADI scheme for (2+1)-dimension nonlinear Sine-Gordon equation.

通过引进参数，分别为（1+1）维的非线性Sine-Gordon方程和广义的非线性Sine-Gordon方程建立了它们的加权隐式差分格式，给出了（2+1）维的非线性Sine-Gordon方程的ADI格式。

Starting with the basic concept about particle transport and the universal form of transport equation, the discuss is concentrated upon the transport equation and the implicit difference scheme under 3-D Cartesian coordinate, as well as the transport equation and the discontinuous finite element scheme under 2-D cylindrical geometry.

从粒子输运的基本概念和输运方程的一般形式入手，重点讨论了三维直角坐标中子输运方程和隐式差分格式，以及二维柱坐标中子输运方程和间断有限元格式。

In this paper, a high order accuracy difference method is presented for solving unsteady convection diffusion equation by using Implicit Perturbation Finite Difference scheme. Firstly, we use the steady convection diffusion equation, the constant coefficients of this equation are expanded to power series of grid-spacings, then the high-order Perturbation Finite Difference scheme is obtained by determining the coefficients of the power series. Put this scheme on unsteady convection diffusion equations and modified it, the IPFD scheme is constructed.

本文利用摄动差分思想，对定常对流扩散方程中的空间微商系数进行摄动展开，展开幂级数系数通过消去摄动格式修正微分方程的截断误差项求出，由此获得方程的隐式摄动差分格式，将此方法应用于非定常对流扩散方程，并加以修正，得到该方程的修正隐式摄动差分格式。

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。

For gas flow past cylinder, the characters of flow field in different Mach number and Knudsen number condition were investigated, and especially for low Knudsen number cases, the results were compared with calculating results of Euler's equation. It showed that they are correspondent by comparing the characters of bow shock and wake. The convergence rates of different high resolution and implicit schemes were also investigated. The convergence behavior of the implicit WENO scheme developed in this paper is better than others. For gas flow past NACA 0012 airfoil, the calculating results were compared with results of experiment. It showed that the results of WENO scheme are of higher accuracy for the case with angle of attack.

在圆柱流场时，我们探讨不同马赫数且不同纽森数时的流场特性，并在低纽森数时，与那维尔-史托克方程式的计算结果比较，我们比较了弓形震波及尾流附近的特性，其结果是相当符合的，同时我们也比较不同高解析隐式算则的收敛历程，从收敛历程图可得到，本文发展出来的隐式WENO算则有较佳的收敛效果；在NACA 0012翼形的流场中，我们将与实验结果做比较，发现利用WENO算则计算的结果，对於具有攻角的流场，亦有相当高的准确度。

After explaining total design of automated test system for microcircuit , the thesis introduces GPIB standard .

文章在说明了微电路模块自动测试系统的总体设计后，对GPIB标准进行了介绍。

He interceded in my behalf.

他替我说情。