波的传播

SH guided wave dispersion characteristics and wave structure for free surface isotropic elastic pipe circumferential waveguide were calculated and analyzed to guide pipeline inspection,and these characteristics were compared with those of the plate SH guided wave.

为指导基于超声导波的管道无损检测，计算并分析水平切变（shear horizontal，SH）导波在具有自由内表面、外表面的弹性各向同性管道周向波导中传播的频散和波结构特性，将这些特性与平板SH导波的对应特性进行对比分析。

In this paper, an all fluid Kraken normal model is employed to analyze the propagation characteristics of shallow water channels.

本文采用了一种全液态Kraken简正波模型，对位于浅海信道的目标海区的传播特性进行分析，得到了不同传播条件下信道的传播损失和频率特性图，为水声通信系统的设计提供了理论基础。

From the results obtained it can be found that, in dispersion curves higher branches cut on as fluid waves and then quickly change their behaviour to that of shell waves described by plateaux, finally they convert to fluid waves again.

研究结果发现，频散曲线中高阶分支曲线所代表的波都是以流体型波开始传播的，然后再转变为平直段的壳体型波，最后又转变为流体型波。

Based on two order approximation of the variation of refraction index produced by self-action while optical pulses are traveling in Kerr-medium,the propagation equation has been solved.Furthermore,the strict analytical expressions of the amplitu

文摘：将光脉冲在克尔介质中自作用产生的折射率变化作二阶近似，求解所得到的传播方程，得到啁啾高斯脉冲幅度，脉冲宽度和周啾参数随传播距离变化的严格解析解，讨论了基模高斯脉冲孤波传播的条件。

It is found that the characteristic equations for right hand and left hand circularly polarized waves are identical.

在这种波导中，右旋和左旋圆极化波的特征方程是相同的，因此，它们的传播常数也是一样的；而当线极化波通过这种波导时，不出现极化面的旋转。

Therelationship between the turbulent kinetic energy and its dissipation rate,whichis widely used to parameterize the dissipation rate in turbulence closure models,is found to hold well for both reversing and rotating flows,but with differentcoefficients.Microstructure profiling measurements at two comparative stations (a deepercentral basin and a local shelf break) in the stratified Yellow Sea are analyzed,with emphasis on tidal and internal-wave induced turbulence near the bottomand in the pyenocline.The water column has a distinct three-layer thermohaline structure,consisting of weakly stratified surface and bottom boundary layers anda narrow sharp pycnocline.Turbulence in the surface layer is controlled by thediurnal cycle of buoyancy flux and wind forcing at the sea surface.while thebottom stress induced by barotropic tidal eurrents dominates turbulence in thebottom boundary layer.The maximum level at which the tidally enhanced mixingcan affect generally depends on the magnitude of the tidal current,and it canbe up to 10-15 m in the Yellow Sea.This suggests that,in the deeper regionsof the shelf seas,turbulent dissipation and mixing are very weak at the levelsbetween the near-bottom tidally enhanced layer and the pycnocline.Therefore,these levels provide a significant bottle neck for the vertical exchanges.In theshallow regions,however,the tidally-induced turbulence can occupy the wholewater colum below the pycnocline.A quarter-diurnal periodicities of the turbulentdissipation rate and eddy diffusivity are found at different heights with evidenttime lag.In the relatively flat central basin,the pycnocline is essentially non-turbulent and internal-wave activity is very weak.Therefore,vertical fluxes acrossthe pycnocline decreased to molecular levels.In contrast,internal waves of variousperiods can be always found near the local shelf break.

对强层化季节黄海两对比性站位(分别位于中央海盆区与局地陆坡区)处层化、内波以及湍流混合特征的研究结果表明：1、强层化季节的陆架海水体一般呈现显著的三层热盐结构，在水体近乎混合均匀的上混合层与潮流底边界层之间为强跃层；2、近表层水体的湍流混合强度主要由海表浮力通量的日变化与海表风强迫控制，而在潮流底边界层内，潮混合是水体热量、物质、动量与能量垂直交换的主要机制；3、潮混合影响的深度由潮流大小决定，在黄海，一般可达10-15 m，因此，在水深较深的区域，在跃层与潮混合所至深度范围的上界之间存在湍流混合非常弱的区域，这显著抑制水体内物质的垂直通量，为物质垂直交换的瓶颈，而在水深较浅的区域，潮混合影响范围可至跃层底部，因此物质在跃层以下整个水体中混合非常均匀，当跃层内间歇性强混合发生时，可以产生显著的跨跃层物质输运；4、近底潮致强湍流耗散缓慢地向上传播，底上不同深度处垂直湍扩散系数也具有显著的位相差异，且二者均随时间呈现四分之一周日周期的变化；5、在地形较为平坦的中央海盆区，内波活动非常微弱，因此跃层内湍流混合非常弱，垂直扩散系数为分子扩散水平，跨跃层物质通量受到显著抑制，而在地形变化较为显著的局地陆坡区，内波活动非常活跃，除内潮的影响外，高频内波与内孤立波的影响也很显著，因此跃层内存在很强的间歇性强混合，内孤立波存在的区域，水体湍流混合显著增强。

Numerical results indicate that in some cases detonation wave may quench when detonation wave front diffracts at the entrance of expanding chamber due to the extreme declination of temperature and pressure.

结果表明，爆轰波传播至突变截面扩张管道时，由于稀疏波的作用可能会使爆轰波局部熄爆甚至完全熄爆，对于某些敏感度高的反应气体爆轰波可以二次起爆。

The ideal to be aimed at was to devise an instrument that could record with a pen on paper, the movements of the ground or of the table as the quake passed by.

首先记录下的是纵向波的到达；然后记录下的是横向波的到达，横向波比纵向波传播得慢，在纵向波到过几分钟后能到达。

3D effect is analyzed and the average velocity of wave propagating in the pile, which mainly influences inverse interpretation, is discussed. Finally, the theory results are verified by model experiment. It is shown that 3D results have the same phase with ID results. The pile radius, the duration of impulse, the ratio of hammer radius to pile radius and shear velocity of the soil around the pile have influences on 3D effect. The best position of receiver is 0.55R from the pile center. The average velocity of wave propagating in the pile reduces due to transversal inertia effect and 3D effect.

结果表明：三维曲线与一维结果在相位特征上一致；波场图直观地反映了波在桩中的传播规律；三维效应与桩径、激振脉冲宽度、相对激振半径及桩周土剪切波速有关；传感器放在0.55R处可以得到干扰较小的信号；三维效应和横向惯性效应的存在会使桩中的波速减小，土的性质对波速影响不大；反演精度与缺陷的性质、激振条件有关。

The study on Rayleigh wave characteristics in layered soil shows that shear wave velocity of soil can be attained.

许多学者对瑞利波在地基中的传播特性的研究表明，瑞利波能够反演地基土的剪切波速度，而剪切波速度跟地基土特性又有联系，因此，可以利用瑞利波法来反演地基土的特性。

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。