波的传播

Water waves travel in expanding circles, and air waves in expanding spheres.

水波是以不断扩大的圆圈来传播，而空气波是以不断扩大的球体来传播的。

Different from the scattering theory used in the derivation of conventional generalized screen propagator, in this paper, a high order formula of generalized screen propagator for oneway wave equation is proposed by using the asymptotic expansion of singlesquareroot operator.

不同于常规广义屏传播算子的推导中使用散射理论，本文利用单平方根算子的渐近展开，推导出了单程波方程广义屏传播算子的高阶表达式。

Carrier wave and modulating wave with high frequency were used to control the exciting current and frequency respectively.

可用于波流共存场多向随机波浪传播变形的模拟和预报。9。利用载波和高频调幅波分别控制励磁电流(0~15 A)和励磁频率(50~1000 Hz)的大小。

The two small cells born at southeast of Beijing develop rapidly and gradually move northwestward into urban area.

分析还表明，20：00左右的超强雷达回波是由大气异常传播造成的虚假超折射回波。

It was found that the pulse distortion can be quite severe depending on frequency, pulse width ,and path length.

应用傅立叶时域积分近似解方法对毫米脉冲波通过雨媒质时的传输特性进行了研究和分析，得出了脉冲畸变随频率、降雨率、脉冲宽度及传播距离的变化关系，讨论了脉冲展宽与压缩随传播常数二阶导数的关系。

Based on the localization properties of wavefield decomposition and propagation in the beamlet domain, and according to relevant extrapolation formula, the beamlet domain is implemented, and finally imaging values are computed using image-forming condition.

利用小波束域波场分解和传播在空间和方向上的双重局域性，将小波束域波场依据相应的外推公式进行延拓，最终应用成像条件求取成像值。

Ray-Kirchhoff propagators are kinematically acceptable in the range of seismic frequencies for heterogeneous media, but theoretically suffer congenital deficiencies.

Ray-Kirchhoff传播算子较为精确地描述了波在非均匀介质中传播的运动学特征，其理论上的先天不足依赖于介质的复杂性。

The contents can be outlined as follows. Chap. 1 provides an overview of the studies on transient EM radiation and the propagation of nonsinusoidal waves in lossy medium.

这些进展主要涉及对非正弦波辐射能量慢衰减现象的深入认识以及非正弦波进入有耗媒质中传播时Maxwell方程组的适用性及其求解。

According to the purpose of the research in this paper, 3D elastic theory was chosen. The propagational characteristics of Lamb waves in isotropic and antisotropic materials were modeled and the dispersive curves of Lamb waves in an aluminum plate and a carbon fiber composite lamina were calculated separately through the given parameters of certain plate.

首先，比较了现有对Lamb波传播特性建模的方法，根据本文的研究目的选择三维弹性理论作为研究方法，对各向同性材料和各向异性材料中的Lamb传播特性进行建模。

Ohms radiating coaxial cable is mainly used in tunnel.mine,subway,high building and high way where there is no direct or good radio wave as signal transmission and transmitting and receiving antennas duplex functions,The cables is characterized with low attenuation,lowVSWR,high power capacity,good signal coupling and corrosion resistance.

50欧姆漏泄同轴电缆主要用于隧道、矿井、地铁、大型建筑内及高速公路、铁路等场合无线电波不能直接传播或传播不良的特殊环境内，兼有信号传输线的发送、接收天线的双重功能。具有衰减低、驻波比低、功率容量高，信号耦合性能优良，抗腐蚀性好等特点。

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％。