对称差分

The full space calculation model, which suits for the asymmetric structure sometimes even including air below the surface of medium, can enable simulative result to approach real one. The FDTD algorithm based on the mixed ABCs is proper to calculate the transmission line where the electromagnetic wave is transmitted in order to send electromagnetic energy along central conductor. The calculation efficiency will be raised if the PML absorbing boundary condition is set on both planes of transmitting direction and so is the MUR two-order absorbing boundary condition in the other planes.

全空间计算模型是适合所有的不对称结构的待研究体的，而且包括了介质下面的空气部分，使仿真更加的接近实验真实情况；基于MUR-PML混合吸收边界条件的时域有限差分法非常适合计算传输线这种结构，因为传输线是传送电磁波的，电磁能量主要是沿着中心导带行进，因此在两个传输端面上设置PML完全匹配层吸收边界条件，在其他面上设置MUR二阶吸收边界条件，会大大提高计算效率，而且计算结果与XFDTD仿真软件计算结果相比较，基本趋于一致。

And the numerical solutions of difference equation are regarded as the approximate solutions for the differential equation.

文中首先对对称正则长波方程提出了一个两层和两个三层的有限差分格式。

In this paper, a new method of moving-people detection based on fusion of coterminous frames differencing and background subtraction is proposed.

提出一种基于对称帧间差分与背景减除相结合的运动目标检测和自适应背景更新方法。

Because resistance is not very precise in the testingmagnetorquer device,differential amplifier circuit is not very symmetrically.

在磁力矩器测试设备中，要求电源的电压是可变的，再加上电阻的实际阻值和标定的阻值之间存在误差，造成差分放大器的正负端的不对称。

In the first part we consider the convergence and stability of finite difference scheme for Landau-Lifshitz equation in one dimensions space and 2d radial symmetric Landau-Lifshitz equation.

在第一部分，我们研究一维Landau-Lifshitz方程非齐次边值问题和二维柱对称Landau-Lifshitz方程Neumann边值问题的有限差分格式。

The nonlinear dynamic equations including the initial geometric imperfections of laminated composite cylindrical shells were derived from Hamilton's philosophy. Assuming the transverse displacements to be composed of axially symmetrical part and axially asymmetrical part, the governing equations expressed as displacement forms of dynamic buckling were obtained by Galerkin method. The equations were solved by finite difference method. The effects of impact velocity, lamination angle, initial geometric imperfection on the axial dynamic buckling of laminated composite cylindrical shells were discussed.

由Hamilton原理导出包含初始几何缺陷的复合材料层合圆柱壳的非线性动力方程；将横向位移设为对称及非对称两部分，由Galerkin方法得到以位移形式表达的动力屈曲控制方程，通过有限差分方法求解；讨论了冲击速度、铺层角度、初始几何缺陷等各种因素对复合材料圆柱壳轴向冲击动力屈曲可能产生的影响。

The topics covered in these sections are the geometric interpretation of systems of linear equations, the classification of finite symmetry groups in two and three dimensions, the exponential of a matrix and its application to solving systems of first order linear differential equations with constant coefficients, and Hurwitz's theorem on the composition of quadratic forms.

这些条文所涉及的主题是线性方程组的几何解释，在两个和三个有限对称群的分类方面，一个矩阵及其应用，以解决一阶常系数线性差分方程，系统指数赫尔维茨定理在二次形式组成。

Inspired by Chans double series representation formula of_∞~(10), the author constructs a new difference equation on quintuple products, which leads to clarification on the four symmetric differences that are equivalent in pairs.

受Chan得到的_∞~(10)的二重级数表示公式的启发，作者构造一个新的关于五重积的差分公式，并澄清迄今为止所出现的四个对称差恒等式之间成对等价的关系。

A new background reconstruction algorithm is proposed to overcome the problems in the current algorithms,which is based on sub-blocks and employs symmetrical differencing.

针对现有的背景重构算法存在的问题，提出一种新的算法，该算法基于子块操作，利用对称差分重构背景。

A new background reconstruction algorithm is proposed to overcome the problems in the current algorithms,which is based on sub-block s and employs symmetrical differencing.

针对现有的背景重构算法存在的问题，提出一种新的算法，该算法基于子块操作，利用对称差分重构背景。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。