Two physical quantities, β1 (the ratio of B to P components of displacement) and β2 (the ratio of B to P components of stress), are defined for Rayleigh wave. By the theoretical and numerical analyses, it is found that β1 and β2 ard closely related to the stratified structure of media, gi and β2 are two important physical quantities for the exploration of the structure of the interfaces of layers in stratified media.
By recommanding the absorption boundary condition in developing the combinational method of partial separation of variables and finite differences for computing theoretical seismograms in stratified media,the computation process could be simplified.
A full-wave hybrid algorithm that combines the finite difference time-domain (FDTD) method and the dyadic Green's functions for cylindrically stratified media is used to analyze the impedance and radiation characteristics of this antenna, as well as the mutual coupling effects between the two antenna elements.
The results of the experiment on a model of artificial stratified media on outdoor site show that the bjstatic FM-CW radar has the ability to map stratified media. The vertical resolution is 45cm (when ε=1).
The dispersive characteristics of the Rayleigh waves propagated in a stratified media were analyzed by a time-frequency analysis method,the Reassignment of Smooth Pseudo-Wigner Ville Distribution(RSPWVD). Theoretical simulations and experiments were implemented for the homogeneous half-space and the two-layered half-space.
对分层介质半空间瑞利波的频散特性,用一种时频分析方法——重排的平滑伪魏格纳维尔分布(RSPWVD,Reassign- ment of Smooth Pseudo-Wigner Ville Distribution)进行了分析和研究。
The problem of inverse scattering has received increasing attention in recent years.This paper is a mini review concerning only the methods of inverse scattering in electro-magnetics. They are: 1. Bojarski-Lewis method, 2. Use of inverse boundary conditions,3. Use of ramp response waveform. Inverse scattering in stratified media is mentionedbriefly.
With the normal and abnormal vector wave functions and their conversion relations, the multipole expansion expression of radiation and scattering fields for the buried object in the stratified media is presented. The result coincides with the formula derived by Prof. K. K. Mei, but the proving is simpler and more reasonable. This technique and computation can be applied to some other boundary value problems in which boundary conditions must be described with spherical and rectangular coordinates.
In this papar the general expressions of stratified media dyadic Green'sfunction for both plane wave and cylindrical wave expansions are given.The derivation of the transmission coefficients in these expressions usingthe method of wave matrix is also given.