查询词典 wave equation

So, in this paper, a circular cavity witha large radius is used to replace the straight boundary of thehalf space, then the half space problem can be changed tothe scattering problem of two circular cavities to the steadyincident P-wave . Having the aid of the mature cylinderfunction theory, the general solutions of the wave functionscan be given, and an infinite linear algebraic equations ofthe unknown coefficients in the wave functions can be gottenwith the boundary conditions and the Fourier complex seriesexpansion technology, the infinite linear algebraic equationscan be approximately solved by the finite trunction withsatisfying some definite precision, at the basis of thissolution of the equation, the variations and the lay-outs ofthe DSCF at the circular cavity boundary vs. the differentincident angles, the different embedded depths of thecircular cavity as well as the different dimensionless wavenumber of the incident P-wave.

为此，本文采用一个半径很大的圆孔来代替半空间的直边界，将该半空间问题转化为一无限大空间中两个圆孔对稳态P波的共同散射问题，借助于成熟的柱函数理论，通过写出问题波函数的一般形式解，利用问题的边界条件，并采用复数傅立叶级数展开技术将其化为一个仅包含问题波函数中未知系数的一无穷线性代数方程组，在满足一定计算精度的前提下，通过有限项截断进行近似求解，进而讨论了圆孔边界处的动应力集中系数随不同入射角、不同的圆孔掩埋深度、入射波的不同无量纲波数以及介质的泊松比变化和分布情况。

Second, based on the spherical vector wave function in uniaxial anisotropic medium, and the first, second, third and fourth spherical Bessel functions satisfy the same differential equation and recursive formula. The scattering fields in terms of spherical vector wave function from a uniaxial anisotropic spherical shell and an anisotropic uniaxial-coated conducting sphere by a plane wave are derived. The electromagnetic fields in uniaxial anisotropic medium and free space can be expressed in terms of spherical vector wave functions in uniaxial anisotropic media and isotropic medium.

二、在建立均匀各向异性单轴介质球矢量波函数理论的基础上，利用二阶线性偏微分方程的性质和第一、第二、第三和第四类球Bessel函数满足相同的微分方程和递推关系，我们分别研究了单轴介质球壳和单轴介质涂覆导体球对平面波的电磁散射特性，首先给出了各个区域的电磁场用球矢量波函数来表示的解析表达式，进而利用电磁场在边界上满足电磁场切向连续的边界条件和球谐函数的正交性，得出了各向异性单轴介质球结构中电磁场用球矢量波函数表示的系数所满足的矩阵方程。

Based on basic theory of elastic wave propagation, wave equation forpropagation of elastic wave in 2 dimension vertical inhomogeneous mediumof similar concrete cutoff wall model is developed. 2 dimension elastic sheetof concrete cutoff wall is established to research law and energy distributionrelations between propagation, attenuation, reflection and transmission ofelastic wave in concrete cutoff wall; Based on the concept of resolution, thecontent of vertical reflection method used to inspect concrete cutoff wallresolution is raised and factors will have influences on resolution are analyzed,expression of defective layer composite reflection factor and detectabledefective layer maximum thickness are developed; Relations between allsteps of sampling system of vertical reflection are build, the influence ofcentrum characteristics and receiving sensor on testing results are analyzed,therefore parameter requirements for testing instrument and parameter selection principle of collected parameters are raised.

2从弹性波传播的基本理论研究出发，推导了弹性波在类似混凝土防渗墙模型的二维垂向不均匀介质中传播的波动方程式；建立了混凝土防渗墙二维弹性薄板模型，研究弹性波在混凝土防渗墙中的传播、衰减、反射、透射规律及能量分配关系；从分辨率的概念出发，提出了垂直反射法检测混凝土防渗墙分辨率的内涵，对影响分辨率的因素进行了分析，推导出了缺陷层复合反射系数、可检测缺陷层极限厚度的表达式；建立了垂直反射法采样系统各环节之间的关系，研究分析了震源特性、接收传感器对测试结果的影响，提出了对测试仪器参数的要求及采集参数的选择原则。

As the foundation of ultrasonic testing of composite materials, this thesis is intended to explore in detail a number of features of wave propagation in anisotropic plates, and the following essential problems will be considered:(1) Propagation of plane bulk waves in homogeneous and orthotropic anisotropic media;(2) Lamb wave propagation in multilayered anisotropic plates;(3) Influence of isotropic solid or liquid loading on Lamb wave propagation in anisotropic solid media;(4) Influence of interface layers on Lamb wave propagation in layered anisotropic composite laminates;(5) Dispersion characteristic analysis of attenuation Lamb wave while existing an thin viscous layer which is used for simulating the poor curing in adhesively bonded joints.

作为复合材料超声检测的基础，本文研究了如下国际前沿性的课题：（1）平面体波在正交均匀各向异性媒质中的传播；（2）多层各向异性媒质中Lamb波的传播；（3）各向同性固体或液体负载对各向异性固体媒质中Lamb波传播的影响；（4）界面层对层状各向异性复合媒质中Lamb波传播的影响；（5）胶粘剂未固化而呈现粘弹性时粘接结构中衰减Lamb波的频散特性分析。

The paper presents a linear transient solution for the solitary wave generated by a piston-type paddle in a finite flume based on the boundary condition derived by Dean and Dalrymple (1991). The wavemaker problem is simplified by decomposing the wave potential into two parts. One is the evanescent wave and the other is progressive wave. The possible solution for the evanescent wave is expressed in form of the Fourier series.

本文根据Dean与Dalrymple（1991）描述造波水槽内部之线性边界条件，将水槽内部之流速势分为振荡波与前进波以简化问题，再以Fourier级数展开，可将问题化为二非齐次常微分方程式，在给定造波初始条件的情况下即可解析有限长度造波水槽自静止开始造波一段时间后停止之线性暂态解。

Compared with the initial value problems of scalar conservation laws with smooth flux function, the global weak entropy solutions for the initial-boundary value problems of scalar conservation laws with weak discontinuous flux function include the following new interaction types: a rarefaction wave collides with the boundary and is absorbed compltetely or partially by the boundary; a rarefaction wave collides with the boundary and the boundary will reflect a contact or non-contact shock wave; a contact or non-contact shock wave collides with the boundary and is absorbed by the boundary; a contact or non-contact shock wave collides with the boundary and a new non-contact shock will rebound from the boundary simultaneously or later.

与具有光滑流函数的单个守恒律的初始值问题相比，具有弱间断流函数的单个守恒律初边值问题的整体弱熵解中包括下列新的相互作用类型：稀疏波碰到边界并被边界部分或全部吸收；稀疏波与边界相撞，边界反射出一个接触或非接触激波；接触或非接触激波碰到边界并被边界吸收；接触或非接触激波与边界相撞，边界同时或稍后反射出一个新的非接触激波。

Results: Objective hearing loss were at different levels, with the main wave (including wave ⅠⅢ and Ⅴ) having 4 kinds: with each wave peak latencies and interpeak latencies at normal range; with each wave PL prolonged but IPL at normal range; with IPL prolonged; and main wave being absent dissimilarly.

结果 客观听力不同程度损失，主波分化有4种情况：①Ⅰ、Ⅲ、Ⅴ波都能引出，各主波峰潜伏期、峰间潜伏期在正常范围；②Ⅰ、Ⅲ、Ⅴ波都能引出，IPL均延长，IPL正常；③Ⅰ、Ⅲ、Ⅴ波都能引出，IPL延长；④各主波有不等缺失。

Based on the item of national high technology development project, the thesis studies the reasonable construction pattern of the tunnel portal, incidence of the micro-pressure wave and the the effect of bell-mouthed hood, lacunaris hood and expansile hood on alleviating the micro-pressure wave in the situations of single line and double line, obtains the relationship between the max micro-pressure wave and the velocity of the train as well as the relationship between the max micro-pressure wave and distance of measuring point at the velocity of 100km/h-550km/h, compares the different alleviative effect of the three different hood to max micro-pressure wave and finally proposes the reasonable construction pattern of the tunnel portal.

本文针对国家高技术研究发展计划(863计划)课题"磁浮交通沪杭线越黄浦江隧道的工程技术问题研究"，在单洞单线和单洞双线两种工况下，对隧道洞口的合理结构形式和影响范围，以及洞口喇叭形入口缓冲段、多孔壁入口缓冲段以及隧道出口膨胀室对减缓微压波的作用进行了研究，得到了磁浮列车速度在100km/h～550km/h时隧道出口微压波最大值与速度的关系以及微压波最大值与测点距离的关系，比较了三种不同形式缓冲结构对微压波最大值的减缓效果，提出了隧道洞口的合理结构形式。

Derives the formulae for calculating the distortion and stress on the acting surface of flexspline load in the drive process of the harmonic gear drive with three-wave wavegenerator;(2) analyzes and compares the performance of plastic and steel products under light load drive and calculates the probably reached limit of drive ratio for both types of flexsplines under the same load;(3) applies the harmonic gear drive with three-wave wavegenerator to the small-sized multiple-revolution electric device of valves by taking into consideration of the low limit of the drive ratio for the harmonic gear drive with three-wave wavegenerator made of plastics, improves the design on the main drive mechanism of the traditional small-sized multiple-revolution electric device of valves, and validates through examples the feasibility for the harmonic gear drive with three-wave wavegenerator made of plastics to be applied to the small-sized multiple-revolution electric device of valves. Finally the author performs calculations on the two types of the flexsplines of the harmonic gear with three-wave wavegenerator by using the finite element method and analyzes the causes for the errors.

本文根据三波谐波齿轮传动的运动变形特点，采用弹性薄壳的力矩理论，推导了三波谐波齿轮传动柔轮载荷作用面上的变形及应力计算公式；分析比较了轻载传动情况下塑料和钢材的性能，计算了塑料制谐波柔轮和钢制谐波柔轮在相同载荷情况下可能达到的传动比极限；对塑料制及钢制三波谐波齿轮柔轮进行了有限元计算，分析了产生误差的原因；针对三波塑料谐波齿轮传动比极限低的特点，将之运用于小转矩多回转阀门电动装置中，对传统的小型多回转阀门电动装置的主传动机构进行了改良设计，并通过实例验证了三波塑料谐波齿轮传动在小转矩多回转阀门电动装置中应用的可行性。

Through S-wave polarization scanning mode of ultrasonic impulse testing, rock samples with three different properties are measured to evaluate the variation of S-wave velocity in three perpendicular coordinates. By analyzing S-wave splitting of three directions and polarization of the maximum or minimum speed S-wave amplitudes, we think that the velocity orthotropy and fracture orientation observed in the grain sandstones and crack marble samples can be estimated in terms of the polarization and velocity of S-wave. Also, perpendicularity characteristics on the two types of rocks can attribute to the bedding and structure of rocks (directional grains or crystallize).

在实验室通过选择了三种不同岩性的岩石，采用超声脉冲测试方法中的横波偏振扫描方式，观测了岩石样品三个坐标方向上的横波速度变化，通过分析三个传播方向上出现横波分裂的差异，以及出现最大或最小快慢横波振幅的偏振方向发现，可从横波偏振方向和速度值判断出纹理砂岩和裂隙大理岩样品存在不同程度的速度正交各向异性和裂隙方向等特征，认为这两种岩石的正交特性的原因是岩石的层理或裂隙与岩石本身的结构构成的。

The changes of the HAF after liver injury may be related to the volume of blood loss, the intraabdominal pressure and the pneumoperitoneum duration.

肝撞击伤伴失血后肝动脉血流量的变化与失血量、气腹压力以及气腹持续时间等有密切联系。

Reneging on our commitments to the world's poor cannot be an austerity measure, she said.

放弃我们给世界上的穷国的承诺不能成为一种紧缩措施。