查询词典 calculus of finite differences

At the same time,the finite element model of base plate is used in modal analysis and transient dynamic analysis by means of the elasticity finite element method.

为了优化发射器座钣的结构设计，采用有限单元法对某型号发射器座钣三维空间板壳结构进行了整体三维建模，同时运用弹性力学有限元法对座钣建立的有限元模型进行模态分析和瞬态动力学分析。

With consideration of various analysis methods for reinforced embankment, the model of homogeneous earth slope is setup on the base of Finite Element Method. Using ANSYS-APDL language, the nonlinear finite element program for static analysis of the high reinforced embankments is made in this paper.

在综合考虑加筋路堤各种分析方法的基础上，利用ANSYS的APDL语言，建立了基于有限元法的加筋路堤参数化模型，编写了对加筋路堤进行稳定性分析的非线性有限元程序，并且综合各种影响因素对加筋路堤结构进行优化设计。

The finite difference approximation for this equation is presented.The stability and convergence of the finite difference approximation are analyzed.

并证明了显式格式条件稳定和条件收敛，而隐式格式则是无条件稳定和无条件收敛。

In order to solve the problem,starting from the analysis of the simplest plane wave numerical theory,we derived the formula of relative phase velocity and group velocity under the condition of arbitrary high-order finite-difference approximation,and gave the computational method for acquiring the optimum Courant number,and then analyzed the anisotropic effects due to finite difference approximation.

针对此，从最简单的平面波数值理论分析出发，推导了任意高阶有限差分近似条件下相对相速度和相对群速度的计算公式，给出了求解最佳Courant数的计算方法，分析了差分近似造成的各向异性效应。

A new scheme for approximating the solution of 2D Maxwell's equations-the high order symplectic scheme is proposed to overcome the shortcoming of the conventional finite difference time domain. The scheme is obtained by discretizing the Maxwell's equations in time domain based on symplectic scheme with high order, and then evaluating the equation in spatial domain with second or fourth order finite difference approximation.

为克服标准时域有限差分方法的缺陷，引入一种新的数值计算方法－高阶辛算法求解Maxwell方程，即在时间上用高阶辛差分格式离散，空间分别采用二阶及四阶精度的差分格式离散。

College of Guandong Business, Guanzhou 510320, China）Abstract: Since large-scale vertical quench furnace is voluminous, whose working condition is a typically complex process with distributed parameter, nonlinear, multi-inputs/multi-outputs, close coupled variables, etc, dynamically decoupling control algorithm of temperature distributed parameter system in the furnace was presented, by which the whole system was decoupled to several subsystems and the implementation of controller was simplified. With finite difference approximation, the space and time step size was solved to ensure the convergency of finite difference approximation. After decoupling, the subsystems were controlled with self-learning PID control algorithm. The results show that the temperature control precision and homogeneity are improved; the overshoot and process in temperature rising period are reduced simultaneity.

摘 要：针对大型立式淬火炉体积庞大，工况复杂，炉内温度分布呈本征非均匀性，具有多输入/多输出、非线性、强耦合等特性，难以实现炉内温度高精度高均匀性控制目标等问题，提出一种温度分布参数系统动态解耦控制算法，其原理是：采用有限维逼近方法将对象解耦为多个独立的子系统，简化控制器的实现过程；通过分析有限维逼近方法的收敛性，获得保证收敛性的空间和时间步长应满足的条件；解耦后的子系统采用自学习PID控制算法，实现炉内温度高精度和高均匀性控制以及升温过程的快速性和小超调。

It contains boththe finite element equations and finite difference equations in one equation.

拟协调元法是广义协调方程的解，自然满足平衡对弱连续条件的要求。

There are many ways to analysis and computation of Mikthw's two rotations equation,finite difference method is the most one while using the finite difference method,a flood of data need be collected and computed.

而在目前高性能计算机系统中，最广泛使用的并行环境是MPI(Message Pass-ing Interface)，它已成为一种并行程序的标准。

Maxwell's equations are replaced by a set of finite difference equation. If we solve it in time domain, we can get Finite Difference Time domain method.

从麦克斯韦方程出发建立地质雷达的数学模型，麦克斯韦方程可以转化成有限差分方程组，若在时域中对其求解就是时域有限差分方法。

The main contents of this course include: the construction, convergence, compatibility and stability of finite difference scheme of elliptic equation, parabolic equation and hyperbolic equation, the construction method and computation format of finite difference scheme of a system of partial differential equations.

本课程主要内容有：椭圆型方程的有限差分格式的构造，有限差分格式的收敛性，相容性及稳定性、抛物型方程的有限差分格式的构造，有限差分格式的收敛性，相容性及稳定性、双曲型方程的有限差分格式的构造，有限差分格式的收敛性，相容性及稳定性、偏微分方程组的有限差分格式的构造方法及有关的计算格式。

You can snipe the second and third union leaders from this position.

您可以鹬第二和第三工会领袖从这一立场出发。

Aiming at the currently shortage of XML streams quality detecting, this paper proposes a new forecasting method of XML streams quality by least squares support vector machines, which is used the method of XML keys' vector matrix as windows, and vector product wavelet transform to multilevel decompose and refactor the XML streams series, that can fulfill real-time checking demand of XML quality, and ensure constraint, consist- ency and integrality. For even more adapting net load, it proposes a control strategy by weight and adaptive adjustment to ensure XML streams quality.

针对当前XML数据流质量检测存在的不足，提出构建XML键的矢量矩阵作为窗口，利用矢量积小波变换多级分解与重构XML数据流，再结合最小二乘支持向量机对XML数据流质量进行预测的一种方法，满足XML数据流质量重构时实时检测的要求，保证XML数据的约束性、一致性与完整性；为了更好的适应网络负载，采取加权与自适应窗口调整等调度策略充分保证XML数据流的质量检测。