查询词典 wave theory

Here, the theory and the deducing process of the SEM based on the Legendre polynomial is given. The SEM can get a global diagonal mass matrix, which leads to a very simple explicit time difference scheme and high efficiency. Numerical simulation in the transversely isotropic medium are shown and the results approved that the SEM is a effective method for seismic wave modeling.

文中阐述了基于Legendre多项式的谱元法的理论和推导过程，该方法可以形成全局对角质量矩阵，在时间域使用显式的差分算法，提高运算效率，最后通过横向各向同性介质的数值计算，模拟结果表明该方法是一种有效的数值模拟方法。

By using slowly-varying envelope approximation, a family of solutions of the paraxial wave equation are found in theory, which represents a new family of ultrashort pulsed beams called ultrashort pulsed complex argument Sinc-Gaussian beams.

杨振峰 河北科技大学经济管理学院，石家庄 050018杨振军河北师范大学物理学院，石家庄 050016胡巍华南师范大学传输光学实验室，广州 510631利用理论解析推导的方法，在傍轴近似条件下，给出了一组新的超短脉冲光束的解析解，称为超短脉冲复宗量辛格高斯光束。

This burst waveform has benefits compared to a continuous wave emission in that the laser peak power can be very high for measuring long distances, yet the average power can be kept low for eye safety. And more, the pre-amplified optical receiver possessing temperature compensation and feedback resistance noise compensation is designed which is based on the noise spectrum density theory of silicon avalanche-photodiode.

同时根据硅雪崩光电二极管噪声谱密度理论，设计了具有温度补偿和反馈电阻噪声补偿的激光测距仪前放接收模块，详细分析了背景光，反向高压和反馈电阻对于Si-APD接收性能的影响。

Moreover,a numerical model of embeded pipeline/soil interaction under complex wave laod is developed, the behavior of pipeline in the liquefied soil is simulated base on finite distortion theory, finaly the influence factors are analysed and a set of conclusions are put forward.

建立了复杂波浪荷载作用下埋置管线与周围土体相互作用的数学模型，并基于大变形理论，对管线在液化土体中的移动进行了模拟，并对影响土体液化和管线在液化土体中行为的因素进行了分析。

In order to solve the problem,starting from the analysis of the simplest plane wave numerical theory,we derived the formula of relative phase velocity and group velocity under the condition of arbitrary high-order finite-difference approximation,and gave the computational method for acquiring the optimum Courant number,and then analyzed the anisotropic effects due to finite difference approximation.

针对此，从最简单的平面波数值理论分析出发，推导了任意高阶有限差分近似条件下相对相速度和相对群速度的计算公式，给出了求解最佳Courant数的计算方法，分析了差分近似造成的各向异性效应。

A new method relying on the Stroh formulism and the theory of the surface impedance tensor was developed to investigate the dynamic instability of interfacial slip waves.The concept of the surface impedance tensor was extended to the case where the wave speed is of a complex value,and the boundary conditions at the frictionally contacting interface were expressed by the surface impedance tensor.Then the boundary value problem was transformed to searching for zeroes of a complex polynomial in the unit circle...

基于Stroh公式和表面阻抗张量理论，提出了研究界面滑移波动态失稳问题的一种新的方法·该方法将表面阻抗张量概念推广到复波速域，并将摩擦接触界面上的边界条件以表面阻抗张量表示·最终将边值问题化归为求解一个复多项式在单位圆内的根·以弹性半空间与刚体平面相对稳态摩擦滑移为例进行了详细的分析，导出了一个4次复特征方程并讨论了方程在单位圆内解的特性，给出了滑移界面波失稳条件的显式解析表达式

The dissertation presents a number of methods and theory involving in diffraction integral, Fourier transform, directly solving differential wave equation, vector analysis, which can be used to study ultrashort pulsed beams propagating in free space, linear dispersive

现将本论文所得主要结论总结如下：基于瑞利—索末菲衍射积分、角谱法和复解析信号法，推导出了等束腰宽度超短脉冲高斯光束在自由空间的严格的传输方程和傅里叶谱，适用于几个光周期甚至一个光周期以下的超短脉冲光束和大衍射角情形，而不产生空间奇异

Using scalar diffraction theory, Fresnel diffraction and the realization of Fraunhofer diffraction of light waves of wave-front propagation and the application of digital holography to help.

详细说明：采用标量衍射理论，实现菲涅尔衍射和夫琅禾费衍射，对光波的波前传播和数字全息的应用有帮助。

Based on the theory of evanescent wave and mode matching in probe,the geometric figure of probe was designed,and five group probes were made.

根据光纤探针的倏逝波理论和模式匹配理论对光纤探针的几何形状进行了设计，制作了数组光纤探针并根据需要对其中一部分进行荧光标记。

Assuming the initial background is an isothermal and hydrostatic equilibrium atmosphere in which the horizontal pressure gradients are balanced by the geostrophic winds, we study the nonlinear propagation characteristics of the gravity waves, analyze the influence of the earth's rotation on the propagation of gravity wave and compare the simulation results with that obtained by the linear gravity theory.

假设初始背景是满足流体静力学平衡和地转平衡的等温大气，我们研究了重力波的传播特性，分析了地球旋转效应对重力波传播的影响，将模拟结果与线性重力波理论给出的结果及实验观测结果进行了比较。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。