波动方程

In this paper the theory and computation of finite element method is discussed for solving seismic response in anisotropic viscoelastic media, the relations between the attenuation factor and viscosity are presented.

本文论述准各向异性粘弹波动方程有限元数值解地震波响应的原理与计算方法，并给出地震衰减因子与方程中粘滞系数的计算关系式。

On the basis of the dispersion relation, we investigated the properties of nonlinear surface waves. It is shown that there exist backward surface waves, with the phase velocity and group velocity opposite in direction. For transverse electric waves, the nonlinear wave equation is transformed into Bernoulli equation, and the exact solutions of magnetic fields are obtained.

在色散关系的基础上研究了非线性旋磁表面波的频率特性，揭示了该系统能激发后向表面波，其群速度与相速度反向；将反铁磁晶体中TE表面波满足的非线性波动方程变形为伯努利方程，用反函数形式给出了表面波磁场的精确解。

The stable wave-field propagators of one-way wave equation for Born and Rytov approximations are derived by using the local Born and local Rytov approximation methods in the scatter theory of wave-field propagation, and their application effects in prestack depth migration imaging of wave equation are compared theor...

利用波场传播散射理论中的局部Born近似和局部Rytov近似，分别导出了单程波方程的稳定的Born近似波场传播算子和稳定的Rytov近似波场传播算子，然后从理论和实践上比较了它们在地震数据波动方程叠前深度偏移成像中的应用效果。

The model can be designed according to the absolute normal model scale or the distorted model scale, in consideration of the conditions of the test site and water supply capacity etc., this experiment designs model in the light of the distorted model scale . The distorted model scale can satisfy the similarity conditions of surge equation and water hammer equation.

试验模型可以设计成正态，也可以设计成变态，考虑到试验场地、供水能力等因素，模型按变态设计，模型比尺同时满足了波动方程和水击方程的相似条件。

Based on the wave equation of longitudinal vibration of variable cross-session rod, the frequency equation and parameter formula of cosine horn are educed, the cosine horn with same frequency and different area ratio is designed by using Matlab language.

根据变截面杆纵向振动的波动方程，推导了余弦形变幅杆的频率方程和重要参数的计算公式。

To research the propagation characteristics of travelling wave along transmission line in depth, the authors establish a mathematical model of travelling wave along lossless transmission line with the format of discrete time and space mesh lines, derive the stable condition and boundary condition of the wave equations using numerical solution of partial differential equation, and attempt the simplification of the boundary condition to realize full decoupling of voltage and current.

为深入研究行波在配电线路上的传播特性，建立了时间-空间网格线离散格式的无损传输线行波数学模型，采用偏微分方程的数值解法推导了波动方程的稳定条件和边界条件，并尝试对边界条件进行简化，以实现电压和电流的完全解耦。

Firstly, based on the wave equation, determining reasonably its initial boundary condition, the paper establishes a computer diagnostic model of oil pumping mechanical well, the damping factor in the model has been reasonably determined, the implicit difference solutionis conducted to the model by changing of step width expression difference solves, and the half analytical solution is explored to the model - fine integral method; and realizes the transformation from dot indicator diagram to indicator diagram of any section.

首先从抽油机井计算机诊断技术的理论基础入手，考虑多级抽油杆连续性，建立了粘滞阻尼波动方程，合理确定模型中的阻尼系数，采用无条件稳定的隐式差分法及半解析方法求解方程，获得抽油杆柱任意断面和抽油泵处的示功图。

Based on the linear elastodynamics theory, an analytical model is established for the propagation of generalized Rayleigh waves in a coated structure. Moreover, the dispersion equation is derived from the wave motion equations and the boundary conditions.

基于弹性动力学的线性理论，建立了涂层材料中广义瑞利波传播的理论分析模型，并且由波动方程和边界条件推导了波的频散方程。

Nonlinear flexural wave equation is solved by the Jacobi elliptic function expansion method. Two kinds of exact periodic solutions of the nonlinear equations are obtained, that is, the shock wave solution and the solitary wave solution. The necessary condition for existence of exact periodic solutions, shock solution and solitary solution is discussed, which is consistent with the qualitative analysis.

利用Jacobi椭圆函数展开法，对该非线性方程进行求解，得到了非线性波动方程的准确周期解及相对应的孤波解和冲击波解，讨论了这些解存在的必要条件，这与定性分析的结果完全相同。

When the porous solid skeleton is approximately taken as a micropolar medium and the fluid in the pores a point medium, the elastic pragmatic wave equations in a saturated porous micropolar medium are obtained from the results of the micropolar theory and those of Biot's pragmatic wave theory.

利用微极理论和Biot波动理论的研究成果，把饱和土中多孔固体骨架部分近似地视为微极介质，孔隙中的流体部分视为质点介质，获得饱和多孔微极介质的弹性波动方程。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。