查询词典 wave theory

The spread of the periodic wave, the advantage and disadvantage of the solid dynamic theory, the orderly system and the disorderly system physics; It also discuss the classification of the phase transformation and the division between the quantum method and the classical method in the condensed matter physics; and also point out the major developing trend of the present condensed matter physics.

对周期波的传播、固体能带理论的优缺点以及有序体系和无序体系的物理学；相变分类、凝聚态物理中量子方法与经典方法的界定进行了讨论，并指出了凝聚态物理发展的主要方向。

We employ ab initio plane-wave pseudopotential density functional theory to calculate the coordinate,the equilibrium lattice parameters,bulk modulus,shear modulus and elastic constant,and those calculated results agree well with the other experimental data and the theoretical data which have been published.

本文采用平面波赝势密度泛函理论方法计算了PtN2的坐标、平衡态的晶格常数、体模量、剪切模量和弹性常数，计算结果与已有的实验值和理论值吻合较好。

In order to study the influence of defect on the surface acoustic wave,based on the theory of elastodynamics,the interaction between elastic surface acoustic waves and surface-breaking defect was simulated numerically by means of the finite element method.

为了分析材料表面缺陷对声表面波传播的影响，以弹性动力学理论为基础，采用有限元方法数值模拟了声表面波沿金属表面传播及其与表面缺陷的相互作用。

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。

The electromagnetic wave spreads in empty space. This, again, is a consequence of the theory.

电磁波是在空间传播的，这又是一个麦克斯韦理论的结果。

First ,I will talk of some theory about how electromagnetic wave transmits .

为了方便大家的理解，本文还介绍了无线传播的一些理论知识。

According to the theory of wave acoustics and ray acoustics,train is regarded as a moving limited line sound source and the mathematics model of sound field distribution is set up around the elevated railway.

根据波动声学和几何声学原理，将列车看作一运动着的有限长线声源，建立了有声屏障时城市高架轨道交通沿线声场分布计算模型。

The vapour and plasma ignition times of the target are got based on the equation of heat conduction and cascade model. We suppose that the plasma is ignited when 210 generations of new electrons are born in vapour generation time. The influence of temperature on the thermodynamics and optics parameters of material also have been considered in the model. The resulting theory has good agreement with the experiment and overseas report. A blade method to measure the laser spot is given in this paper with validation and error analysis. The plasma threshold of metals in atmosphere and water ambients both are diagnosed with the light deflection and piezoelectric transducer. A Q-switched pulsed Nd:YAG laser operating at infrared (1064nm), visible(532nm) and ultraviolet (355nm) wavelengths has been used. Al、Fe、Cu are used as targets and get a similar results with both method. Theoretical and experimental analyses are applied on the influence of wavelength on the threshold have been done, both of which have shown that the plasma threshold of metals decrease as the laser wavelength increases; The plasma threshold of metals are higher in water than in air and the pressure of the shock wave in water is five times higher than in air.

从热传导方程和雪崩电离机制出发，假设当电子增值2~(10)倍时，考虑了温度对材料热力学和光学参数的影响时，得到了气化和等离子体点燃的时间，利用该模型进行计算得到的结果与国内外报道及自行通过实验测得的阈值基本一致；提出了利用刀刃法测量激光光斑面积的方法，并通过实验进行了验证和误差分析；利用光偏转装置和压电换能器分别对空气和水中金属等离子体点燃阈值进行了实验诊断，激光器均为调Q—YAG激光器(波长1064nm，532nm，355nm，脉宽10ns)，靶材分别为Al、Fe和Cu，两种测试方法得到的等离子体点燃阈值基本一致；本文从实验和理论计算两个方面讨论了波长对等离子体点燃阈值的影响，均得到了等离子体点燃阈值随着波长的增加而减小的结论；对空气中和水中不同环境下金属等离子体的点燃阈值进行了比较研究，得到了金属在水中的等离子体点燃阈值比空气中的大，且水中产生的冲击波的压强是空气中的5倍左右的结论。

In chapter 4, According to the theory of scalar diffraction, firstly, the equipollence of spatial distribution of the plane-wave interferential field and parallel projective sine grating is discussed.

在第四章，根据标量衍射理论，首先讨论了两平面波干涉场的空间分布与平行投影正弦光栅的等价性。

The non-relativistic energies and wave functions were determined by Rayleigh-Ritz method. The relativistic effects, including the correction to kinetic energy, the electron-electron contact term, and the orbit-orbit interaction, Darwin term, and mass-polarization effect on the energies were calculated by using first-order perturbation theory. In order to obtain a more accurate result for the larger Z system, the quantum-electrodynamics correction should be included. This correction to energy can be evaluated for the valence electron by using a hydrogenic formula with an effective nuclear charge, Z. The ionization potential, the excitation energies and the fine structure split-tings for a lithium-like ion with higher nuclear charge (Z=26) were calculated.

非相对论能量用Rayleigh-Ritz变分法确定，包括动能修正、电子—电子接触项、轨道—轨道相互作用项以及Darwin项的相对论修正和质量极化项由全实加关联波函数的一阶微扰给出，量子电动力学修正由有效核电荷方法和类氢公式计算；给出了较高核电荷(Z=26)类锂体系1s^2nl组态的电离能、激发能和1s^2np组态的精细结构劈裂。

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％。