波的传播

Researched influence of frequency on characteristic of electromagnetic wave transmission in tunnels, and analyzed characteristic of electromagnetic wave transmission in circular, arches and curved tunnels by method of metal wave guide, and gives approximate formulas of attenuation rate. Main conclusions we obtain are as follows: in circular,rches tunnels, if frequency is higher, attenuation rate is smaller, it is beneficial for EM waves to transmit, in curved tunnel, higher frequency, more attenuation rate ...

研究了频率对井下电磁波传输特性的影响，采用金属波导法分析了圆形、拱形及弯曲隧道中电磁波的传输特性并给出衰减率近似公式，得出主要结论：在圆形和拱形隧道中，频率越高，衰减率越小，越有利于电磁波的传播；在弯曲隧道中，频率越高，衰减率越大，不利于电磁波的传播；通过特性曲线与井下实验数据相比较得出在900MHz左右为井下无线通信系统传输信号最佳频段。

Deconvolvtion is used to eliminate effects of ghost multirefluction earth filtering when seismic secondary wave spreading. Deconvolution is a special way to eliminate these factors.

地震资料的反褶积处理是针对地震激发子波在传播过程中受虚反射、层间多次和大地滤波等影响，专门用于消除这些因素对地震子波改造的一种处理方法。

Transmission and energy distribution characteristics of Rayleigh waves in layered ground were important for Rayleigh wave test.

掌握瑞利波在分层地基中的传播和能量分布特征是进行瑞利波勘测的关键。

After an arbitrary time, the new position of the wave front will be that of a surface tangent to these secondary wave lets.

介质中波动传播到的各点都可以看作发射子波的波源，而在其后的任意时刻，这些子波的包络就是新的波前，这就是惠更斯原理。

Some knowledge about wave propagation in anisotropic media has been obtained by studying elastic wave propagation properties of the transversely isotropic media.

3深入地研究了横向各向同性介质中弹性波场的传播特征，获得了一些各向异性介质中波传播的重要认识。

Following, a experiment has been carried out, the incident waves with a frequency band of 200kHz-3 50kHz are used to the experiment, and a series of peak value-time curves are drawn each 10kHz, corresponding time are found through fitting peak value, thus the position of the defect is calculated accurately. The application of awl-shaped sensor head in the heat change water pipe experiment indicates that the ultrasonic guided waves may transmit nearly 50 meters in the pipe, which is not influenced by the elbows and makes it possible to test defects in long distance and large-scale. The water-load pipe experiment indicates that the displace and energy maybe leakage at the near-surface, which is significant for the further research.

而后，采用200kHz至350kHz频段的入射波进行了实验验证，并每隔10kHz绘出一条峰值一时间的曲线，通过拟合峰值点，找到对应的时间，从而准确的计算出了缺陷的所在；应用锥形探头的热交换水管的实验表明，超声导波可以在管道中传播了近50米的距离，且不受弯头的影响，从而使得长范围、大规模检测成为可能，水载管实验说明了离面位移和能量可能会发生泄漏的特性，为导波的深入研究和应用作了铺垫。

Because of the nonlinearity, the width of stop band structure decreases, and the pulse attains an instantaneous frequency which depends on the detuned parameter, velocity, intensity and nonlinear coefficient.

在非线性作用下，禁带宽度会变小，波的频率也会发生偏移，其偏移量主要取决于失谐因子、传播速度、波振幅强度以及非线性系数等参量。

The three-dimensional finite element model of guided wave in the pipe was built by the finite element method.

利用有限元方法建立管道导波3-D模型，通过在管道中激励纵向超声波，模拟导波在管道中的传播形态。

The mode simulated the propagation of guided wave in a pipe by applying the longitudinal ultrasonic to the pipe end.

利用有限元方法建立管道导波3-D模型，通过在管道中激励纵向超声波，模拟导波在管道中的传播形态。

The result shows that gravity wave excited by the tropopause forcing can propagate stably to the mesosphere through the stratosphere so that the energy and momentum can be transferred from a region to another. In the propagation, gravity wave undergoes growth, overturning, convection and breaking. The breaking of gravity wave is the important source of convection and smallscale waves, and convective instability and overturn are the character of nonlinear phenomenon.

分析结果表明，从对流层顶激发的重力波能稳定地经平流层传到中层顶，从而将能量和动量从一个区域带到另一个区域；在向上传播过程中，重力波经历了发展、位温翻转、对流直至最终破碎的演变；重力波的破碎是对流和小尺度波动的重要的源，对流不稳定和翻转是非线性现象的一个基本特征。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。