互易定理

Differential scattering field of vertical incident Gaussian beam from a two-dimensional target near a plane interface is studied by means of a new hybrid method based on the reciprocity theorem, the image theory and the method of moment.

基于矩量法、互易性定理及镜像理论，提出了一种新的混合方法用于研究水平分界面上方二维介质目标对垂直入射高斯波束的差值散射场。

Associating with the reciprocity theorem, the second-order coupling scattered fields between the rough sea surface and a 2-D cylinder above it are calculated.

根据得到的表面电流及散射场，结合互易性定理求解了二维柱体同海面之间的二次耦合散射场。

In order to overcome this problem, in this paper, the surface electric current of the conducting sea surface and the first-order scattering from the conducting plate are obtained by employing Physic Optics method. The backscattering field of the time-dependant sea surface is calculated by using Kirchhoff Approximation. Meanwhile, taking the advantage of a newly developed technique that utilizes the reciprocity theorem, the difficulty in formulating the secondary scattered fields from the composite target is reduced. The dependences of the backscattered field on the parameters, such as the wind speed and the sizes of the plate are discussed.

为了克服这一问题，本文应用物理光学近似求解了导体海面表面电流及导体平板的一阶散射场，应用基尔霍夫近似给出了海面的后向散射场，同时借助互易性定理降低了求解平板和海面之间二次耦合散射场的难度，讨论了平板尺寸、风速等对后向复合散射场的影响。

Reciprocity theorem ; EM scattering ; Gaussian beam ; 2D target

互易性定理；电磁散射；高斯波束；二维目标

In order to reduce the effect of probe errors in near-field antenna measurement, the solutions are proposed as follows: On the one hand, theoretical formula of probe-compensated is derived; on the other hand, drop-shaped probe is designed and near-zone gain, far-field patterns, axial ratio, main lobe width, input impedance, voltage standing-wave ratio, electromagnetic field and current distribution of probe are obtained through the computer simulation.

针对近场测量中的重要误差源之一&探头&的影响，本文提出解决方法：一方面用探头补偿的方法，根据洛仑兹互易定理和微波网络理论对补偿的解析式进行详细推导；另一方面用两种不同的仿真软件求解终端开口矩形波导探头的近场增益、远场方向图、轴比、主瓣宽度、输入阻抗、电压驻波比、电场分布、磁场分布、表面电流分布等特性参数，可实现探头增益的修正。

Based on Betti energy iterative law, the damage deformation mechanism of fractured rock mass under stress and seepage pressure has been studied. Furthermore 3D elastic and elastoplastic damage-fracture constitutive relation and damage evolution equation considering seepage pressure have been established.

基于Betti能量互易定理，系统研究了应力场与渗流场共同作用下的岩体损伤演化机制，建立了考虑渗透压力的三维含水裂隙岩体脆弹性和弹塑性断裂损伤本构模型和损伤演化方程。

Calculations on the basis of the self-consistent approximation are used to study the effects of slit cracks, elliptical cracks and penny-shaped cracks. The influence of slit cracks on the elastic moduli under all kinds of loading conditions is discussed by Betti's reciprocal theorem and Irwin's relation describing the released energy rate of fracture to the stress intensity factors. The friction between the cracks' surfaces is taken into account for the closed cracks.

采用自恰方法研究了狭长型，椭圆型及硬币型裂纹在荷载作用下对弹性常数的影响；采用Betti的互易定理以及lrwin关于断裂能量释放率与应力强度因子的关系，分析了狭长型裂纹在各种应力状态下对弹性常数的影响；分析研究了裂纹闭合时，由于裂纹面上摩擦力的存在，闭合裂纹时弹性常数的影响。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。