Theoretical Study Of Acoustic Wave Transmission Property In Layered-medium System

In this paper, we mainly introduce the nonlinear theory, the development of diode, the disordered systems and some basic concepts including the finite difference method and transfer matrix method. The contents of this thesis are introduced as follows:1. The transport properties of acoustic waves in a side-coupled one-dimensional binary chain with short-range correlations are studied by using the transfer matrix method.The results show that the resonant tunneling state is absent in the system whether the side coupled atom is always the same as the corresponding atom in the main chain or not, in which the atoms of main chain randomly appear. There are many resonant tunneling states when the atoms in the main chain are random dimers.2. We assume that the wave propagates in one-dimensional nonlinear system in which the non-linear strength is unevenly distributed. The linear part of equation is derived from wave equation and the nonlinear part is similar to that of Schr?dinger equation. A group of incident waves with equivalent and anastrophic properties act on the model. As a result, the sound wave with a certain frequency and strength has unidirectional permeability in this model and shows behaviors of diode. As the nonlinear strength increase, the unidirectional permeability will enhanced significantly.3. The unidirectional transmission in super lattice with an asymmetric linear layer is investigated theoretically and numerically. The electrons with the same energy are transfused into the model from the positive and negative directions respectively. According to the transmission spectra, it is found that the electron with certain energy has unidirectional permeability in the model; When the transmission mode is given, it is possible to change the size of potential barrier for controlling the energy current and meet the requirement of wave diode.