查询词典 elastic wave

For a heterogeneous elastic solid consisting of two homogeneous layers, three homogeneous layers whose shear wave velocities increasing with depth, or three homogeneous layers whose interlayer has high velocity, if there are multi-mode dispersion curves, the phase velocity V〓 of the first mode will close up to the Rayleigh wave velocity of the bottom layer when frequency f→OHz, and V〓 of the first mode will close up to the Rayleigh wave velocity of the top layer when f→∞.

由多导波模式的相速度频散曲线还可知，对于二层固体介质、结构层的横波速度随深度而递增的三层固体介质、含硬夹层的三层固体介质而言，若频率f→OHz，其基阶模式的瑞利波相速度V〓→V〓（V〓为最底层介质的瑞利波速度）；若f→∞，其基阶模式的V〓→V〓（V〓为最上层介质的瑞利波速度）；因此，随着频率f逐渐升高，野外实测的瑞利波相速度V〓曲线应该主要为基阶导波模式。

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 algorithm of finite element modelling is discussed for elastic wave propagating in two dimensional media. Two analytical formulas of the initial motion and wave form of P wave are derived in time domain for a point force source directing vertically down as a function of time with a bell shape.

本文讨论了二维介质中弹性波有限元模拟的一种方法；导出了二维无界空间中集中力点源的理论初动表达式和位移波形表达式，并和相似情况下的有限元结果进行了比较；对用有限元方法算得的几个中小模型的节点位移进行了分析。

When the velocity proportion of longitudinal wave to transverse wave of a bed is distinctly different from that of another bed, the reflection factor will be changed with the variation of incident angle according to the elastic wave mechanics, which is the foundation of AVO theory.

由弹性波动力学理论可知，当一种岩层纵、横波速度与另一种岩层纵、横波速度之比明显不同时，反射系数随入射角的变化而变化。

In the process of building and using the mass concrete structures, because of the effect of out-side condition and themselves, some faults will form in the structure, these faults will effect the bearing capability and endurance Using nondestructive testing method to test the concrete"s quality and diagnose its healthy, which has the significant sense in assessing the safety stability and research of the administering diseasesThis dissertation mostly researched the testing methods in the mass concrete structure, discussed the principles, methods, features, sphere of application of the ultrasonic testing in the mass concrete structure with faults, used dynamic FEM to simulate the testing process, discussed when the concrete structure with cracks is under the effect of the pulse, how the elastic waves propagate and what are their changing feature, Researched the principles of the first-arriving waves" phase when the cracks" depths are not same, obtained the relation between the inversion point and the cracks" depth, which has the direction sense in the application of projects,The second part of this dissertation is CT , which used the ultrasonic wave running through the tested-substance to get arriving-time of the ultrasonic wave, then inverse the image This dissertation drawed one CT program which can well present the different little cells ultrasonic wave velocity profiles of the substance, thereby to diagnose the quality of the part of the tested-substance, CT has the better using foreground..

在混凝土结构的施工及使用过程中，由于受其自身及外界各种因素的影响，常常会产生一些缺陷，对结构物的承载能力和耐久性造成严重影响，采用无损检测技术进行质量检测和健康诊断，这对混凝土结构开展安全、稳定性评估以及病害隐患治理研究具有重要意义。本论文主要针对大体积混凝土结构缺陷的检测方法展开研究工作，重点讨论了超声波法检测混凝土结构裂缝的基本原理和方法及其特点、适用范围，运用动力有限元数值模拟其检测过程，探讨了有裂缝缺陷的混凝土结构在脉冲荷载作用下弹性波的传播及其变化特征，研究了不同裂缝深度下首波相位变化规律，得出了反转临界点与裂缝深度之间的关系，这对实际工程应用具有指导意义。声波CT是一种新的无损检测技术，它是利用声波穿透被检测体获取声波接收时间，来进行计算机反演成像的技术。本文利用直射线法编制了层析成像程序，能较好地呈现被检测物体各微小单元的声波速度分布图像，从而对检测体的质量状况作出诊断评估，具有较好的应用发展前景。

Based on the hypothesis of rectangle and biconvex section shape of the yarn, and different collocation between the inner warp and outer warp, thickness, section shape of the same structure being considered especially, a model for predicting the elastic property of 2.5-D woven composites was developed. To verify the elastic model, 62 samples of 2.5-D woven composites with 6 various structures were selected and the elastic properties were measured.

基于经纱矩形截面及纬纱双凸透镜截面假设，重点考虑了该结构表层经纱与内部经纱密度的不同及相同机织结构合成不同厚度和纤维束截面的情况，建立了2.5维机织复合材料的弹性性能预测模型。

Bulk stretch silk and differential tussah/mulberry elastic silk, two kinds of new real silk materials recently successfully developed, are investigated in this paper. Their structures and properties are studied, as well as the properties of the cloth. The results show that both of them have good elastic elongation, good elastic recovery and high bulkiness.

膨体弹力真丝和柞/桑弹力真丝是近年来开发的较为成功的二种全真丝新材料，本研究以此为主要研究分析对象，研究分析了膨体弹力真丝和柞/桑弹力真丝的结构和性能，对这两种材料的织物性能也进行探索性研究。

Assuming that linear elastic continuums will deform following the elastic rules of Hook and taking the transformation of linear elastic organs in medical images as that of continuity, Finite element method is used to perform motion analysis, which is non-rigid algorithm based motion.

我们采用基于非刚体的有限元方法对超声心动图像进行运动分析，其中涉及到弹性力学的引入、有限元理论的介绍、单元网格的划分、单元的集成、位移边界条件以及对实验结果的分析。

In view of the usual vertical-horizontal elastic mesh's shortage in left falling stroke and right falling stroke, we present a new elastic mesh structure method—diagonal elastic mesh, which is composed of diagonal beelines of and , and divides the Chinese character image into many diamonds.

针对通常的纵横弹性网格对汉字"撇、捺"笔画特征提取的不足，提出一种新的网格构造技术——对角弹性网格，它由45°和135°的对角直线构成，将汉字图像划分为多个菱形，能够很好地适应汉字在"撇、捺"方向的变化。

There are two different elastic calculation methods in imperfect competition market; they are constant elastic of transition and Armington substitute elastic model.

不完全竞争部门所面临的市场需求弹性计算方法有两种，即通过国产内销商品与出口商品间的CET转换弹性定价模型和通过国产内销商品与进口商品间的Armington替代弹性定价模型。

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。