查询词典 geometric difference equation

Differential Difference Equation; Neutral Functional Differential Equation; Stability Switch; Characteristic Equation; Stability; Liapunov Method; Monotone Semiflow; Periodic Solution

基础科学，数学，数学分析微分差分系统；中立型泛函微分方程；特征方程；稳定性开关；解的稳定性；李雅普诺夫方法；单调半流；周期解

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。

Therefore,it is necessary to research diffusion equation for suspended sediment because it describes the sediment move process in the water body.The equation is a various coefficients second-order linear partial differential equa-tion,such equation under complex boundary condition is very difficult to get its analytical solution,while its numerical solution relative analytical solution is more easier and has the obvious superiority:simple,the computation convenience.but to get a kind of difference format which is good accuracy and stability is not easy.

泥沙扩散方程实际上是一个变系数的二阶线性偏微分方程，这样的方程在各种复杂边界条件下求解是十分困难的，求它的解析解在数学上存在着难以克服的障碍，无法求出其精确解，因此常用数值方法求它的近似解，相比较而言，数值方法有着明显的优势：即简单灵活、计算方便快捷，但要寻找一种精度高、稳定性好、计算方便的差分格式也并非易事。

In this paper, based on summarizing previous numerical studies on wave transformations, deriving an extended form of mild slope equation, which is taken as the governing equation. The equation simulates wave transformation in offshore area with finite difference.

本文在总结概述前人关于缓坡方程波浪数学模型的基础上，推导出一改进型缓坡方程，并以此为控制方程，采用有限差分方法，模拟近海海域的波浪变形。

For example, a regenerative reheating furnace fluid flow and heat transfer is researched, which has simplified the flow and heat transfer of hot air stove according to its real operating conditions.The fluid flow and heat transfer of a hot air stove are numerically simulated by using finite volume method or finite difference method,which bases on the heat transfer equation,flow equation of the gas and heat balance equation.

根据热风炉的实际运行状况对蓄热式热风炉内的流动换热过程进行了合理的简化，并基于热传导方程、气体流动方程和气体的热平衡方程，建立了蓄热体的非稳态传热模型，在对模型利用有限差分法和有限容积法得到离散方程的基础上，采用C 语言编制了模拟计算程序。

The equation of ESCDAC is presented. Secondly, Based on this equation and the independent characteristic of observation valves, the ESR of the azimuth measurement error is presented by full - difference of the measurement equation which acts as the precision of ESCDAC.

然后以该方程为基础，根据该方程中各个观测量相互独立的特点，方位测量误差的均方根值可由测向方程的全微分求得，并将其作为电扫描恒差比幅测向的精度，由该精度公式可以看出，电扫描恒差比幅测向有很高的精度，并且在不同的角度上，其精度保持稳定。

The optimal control law obtained consists of linear analytic functions and a compensation term which is a series sum of the adjoint vectors. The analytic functions can be found by solving a Riccati matrix difference equation and a matrix difference equation. The compensation term can be obtained by a recursion formula that solves adjoint vector equations.

得到的最优输出跟踪控制律由状态向量的线性解析函数和伴随向量级数形式的补偿项组成，其解析函数由一次性求解Riccati矩阵差分方程和矩阵差分方程得到，补偿项由求解伴随向量差分方程的递推公式得到。

The main idea of the finite difference method is as follows: We consider the discrete difference equation with the finite alphas as approximate substitution for the differential equation with the continuous variant and boundary conditions.

有限差分方法的基本思想是用离散的，只含有有限个未知数的差分方程去近似代替连续变量的微分方程及边界条件，并把相应的差分方程解作为微分方程的近似解。

It takesthe weighted average of the L2 norm of the difference of the observation and thesolution of the system and the L2 norm of the difference of conormal derivativeat the different sides of the interface for every subdomain as cost functional andthe smooth coefficients of the subproblem and the value of solution of the originalproblem at interface as identification parameters;Using the property of continu-ous functional defined on compact set,the existence of the optimal solution of theidentification problem is proved;The necessary conditions of optimality charac-terized by the system equation,the adjoit equation and the variational inequalitysimultaneously are given by introducing the conception ofdifferential andadjoit variable;An algorithm is devised and its flow graph is given.

其次，针对分片光滑动力系统的特征，结合正演过程的区域分解算法，建立了分片光滑系统的分解区域参数辨识模型，该模型以子区域上解的实测值与计算值之差的L2范数和界面两侧的通量差的L2范数的加权平均作目标泛函，各子问题的光滑系数及界面上真解的值为待辨识参量；利用紧致集上连续泛函的性质，证明了子区域上参数辨识问题最优辨识参量的存在性；引入微分的概念，借助伴随变量，给出了由系统方程，伴随方程和变分不等式共同表征的最优性必要条件；根据此必要条件设计了算法，给出了算法的程序框图。

The changes of the HAF after liver injury may be related to the volume of blood loss, the intraabdominal pressure and the pneumoperitoneum duration.

肝撞击伤伴失血后肝动脉血流量的变化与失血量、气腹压力以及气腹持续时间等有密切联系。

Reneging on our commitments to the world's poor cannot be an austerity measure, she said.

放弃我们给世界上的穷国的承诺不能成为一种紧缩措施。