波动方程

According to the boundary conditions,Laplace equation of SEW before the media changing abruptly and the homogeneous wave equation after the media changing abruptly were constructed.

结合相应的边界条件，建立了球面电磁波入射到时变媒质时的Laplace方程和时变媒质突变后的齐次波动方程。

It also make students grasp building method and analyzing method of some important mathematical model (such as wave equation,Laplace equation).

使学生熟悉一些重要的电磁场问题的数学模型（如波动方程、拉氏方程等）的建立过程以及分析方法。

In order to probe the absorb coefficients of earth medium by the direct wave, reflected wave and transmied wave amplititude which are picked up from the radar wave racords yielded by finite element method,the paper gives out the attenuated radar wave equations in time domain and the attenuated radar wave differential equations while the motion changes simple harmonic with time and electric parametets change slowly with space.

摘 要 为了用有限元方法生成雷波正演记录，从而拾取直达波、反射波、透射波振幅信息，以确定介质吸收系数，文章在时间域给出了雷达波含衰减项的波动方程，及在运动随时间简谐变化以及电性参数随空间缓变的条件含衰减项的雷达波遵循的简化微分方程。

To a general KdV equation with singular curves on phase plane, we explain the reason why these non-smooth traveling wave solutions arise.Based on the bifurcation analysis, all possible traveling wave solutions have been known qualitatively.

论文的第三章考虑奇异性对非线性波动方程解的结构的影响，针对相空间上出现奇异线的广义KdV方程，详细讨论了奇异线的存在对解的结构的影响，分析系统中非光滑行波解产生的原因。

In order to test spectral element method and Newmark time integral, the codes of program and the feasibility of spectral element method for aeroacoustics, One question which has analytical solution and two typical questions of computational aerocaustics are simulated numerically by the program.

为了验证谱元方程和Newmark时间积分方法的正确性、自己所编程序代码的有效性以及谱元方法求解气动声学问题的可行性，本文使用程序分别求解了具有解析解的波动方程和计算气动声学问题中的两个典型问题。

The standard parabolic equation method was obtained by the decompocition of the scalar wave equation and the expansion of the pseudo-differential operator.

通过对传统波动方程的分解和伪微分算子的近似展开，获得了标准抛物线方程。

TEM field is slowly changing in middle to deep depth prospecting, which is characterized by unperceivable wave and dominant dissemination, thus it can be assumed to be quasi-static state approximate and the wave equation of electromagnetic wave radiation is retrogressive and replaced by diffusion equation.

在中、深层勘探情况下，TEM场是缓变的，其波动性已经很不明显，扩散特征起支配作用，波动方程退化成了扩散方程。

In this paper, the initial-boundary value problem of a kind of nonlinear fourth-order wave equations with damping and source terms is studied on the base of Beam Equation.

本文在梁方程的基础上研究了一类具有非线性阻尼项和力源项的四阶波动方程的初边值问题。

From acoustic wave equation, current continuity equation and boundary conditions, we have solved the interface potential produced by BAWs in interface between piezoelectric solid and semiconductor. The results of YZ LiNb03/n-Si structure with SV wave incidence have been calculated and experimental result has been given. Finally, we have presented some kinds of BAW acoustoelectric convolver structures and analyzed their features.

由声波动方程，边界条件和半导体的电流连续性方程出发，推导出了斜入射体波在压电体/半导体界面产生的界面电势以及通过半导体的作用产生的倍频电势的结果，并且对YZ-LiNb03/n-Si结构，SV波入射的情况进行了计算，给出了部分实验结果，提出了几种可能的体波声电卷积器的结构，并分析了它们各自的特点，理论和实验的结果将为今后这类器件的研制提供依据。

Based on the wave equation in the acoustic fluid space and the theory of thin-wall structure, the uncoupling error in low frequency range about the nonsymmetrical coupled structure-acoustic analysis equation is studied.

该对称模型特征值的非负性及特征问题的可降阶性也在本文中进行了深入研究，同时指出了在复模态分析中应当注意的问题；（2）由声空间波动方程和薄板理论出发，对非对称声振耦合方程的低频解耦误差问题进行了研究。

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。