查询词典 wave propagation

This paper discusses some application cases of the error propagation law by the examples of trigonometrical survey, and presents that not only sum function and numeral multipling function in which there is only one independent observed value but also more complex functions which are equal in mathematics are not opposite in the process of error propagation according to the error propagation law.

1引言本文以三角测量为例，对误差传播定律一些应用问题进行了讨论，指出当只有一个独立的观测值时，和函数与倍数函数运用误差传播定律不会出现悖论；如果在测量工作中有多余的直接观测值，就需用平差后的间接观测值按协方差传播律来计算，这样数学中相等的函数关系才能得到同样的函

After comparing nonlinear simulation with linear, the results indicate that: Weak nonlinearity has definite and apparent influence on the distribution of acoustic fields and focused gain of array, which cause the distribution of waveform is closer to the array and the focused gain deteriorate ; the strong nonlinearity have a strong waveform aberration, because the other waves of non-fundamental frequency appear . No evident distinction is found in the effects between the oblique propagation and the vertical propagation, though less focused gain and influence caused by strong nonlinear produced by the acoustic diffraction which results in more attenuation in terms of oblique propagation.

将线性条件下的模拟结果与非线性条件下的模拟结果进行比较发现：弱非线性会对声场的分布和阵列聚焦增益产生一定的影响，使得声场分布波形比线性条件下的更加靠近阵列，聚焦效果变差；强非线性会使波形发生更严重畸变，这是由于产生了基频以外的其他频率声波引起的；非线性对斜向传播时声场分布的影响与垂直传播时的影响效果基本相同，但由于斜向辐射时的声波衍射造成的衰减要大于垂直辐射时的，因此聚焦增益和强非线性的影响都将小于垂直辐射时的情况。

With the propagation of the input negative-falltime pulse along the transmission line, the capacitance of varactor diodes is decreased by the increase of reverse bias voltage, and the variation in propagation delay at the nodes results in the compression of negative-going wavefronts during propagation.

随着输入脉冲在传输线上的传播，变容二极管的电容随反偏压增大而减小，导致每个节点传播延迟的变化，从而压缩脉冲波前，产生前沿可达1ps的超快脉冲。

The results of conversion show that the serious disc must be rejected because its reliable L-HCCF life is greatly less than an overhaul period. Finally, the load distribution of centrifugal and vibration force on labe is derived. Using two method, load on the crack labe gradually reducing and keeping constant with the crack propagation, a crack propagation analysis of fir-tree slot is carried out, and the calculating L-HCCF crack propagation life of slot on the unload method, which is nearly 3 times longer than that on constant method, is 20 times shorter than the pure low cycle life, and agree well with the experimental's.

最后，分析了离心力载荷和振动载荷在榫齿上的分布，进行了榫槽榫齿的有限元计算；提出了枞树型榫槽的卸载概念，并按带裂纹榫齿上的承载随裂纹增长而逐步减少和始终保持不变两种处理方法，进行了复合疲劳裂纹扩展及其寿命计算，由计算得出卸载下复合疲劳裂纹扩展寿命较单纯低周疲劳寿命下降二十多倍；按卸载处理的疲劳裂纹扩展寿命是按恒载处理的三倍多，前者与试验吻合，而后者则偏差较大。

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。

We develop and apply the Hirota bilinear-θfunction method,Jacobi elliptic function expansion method,linear superposition method and F-expansion method respectively to solve many 2+1 dimensional nonlinear wave models including 2+1 dimensional 2DsG equation,the coupled ZK equation,2+1 dimensional KdV equation,2+1 dimensional long wave short wave resonance interaction equation and 2+1 dimensional dispersive long wave equation,abundant Jacobi elliptic function doubly periodic solutions are derived.These solutions show various periodic wave shapes and special periodic characters.

发展和应用Hirota双线性-θ函数方法，雅克比椭圆函数展开法，线性叠加法，F-函数展开法等分别求解2+1维2DsG方程，耦合ZK方程，2+1维KdV方程，2+1维长波短波共振相互作用方程，2+1维色散长波方程，获得丰富的雅克比椭圆函数双周期波解，描述了一些周期波形态及周期特性。

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。

Objective:To explore the feasibility of laparoscopy in diagnosing and treating of abdominal diseases.

目的：探讨腹腔镜用以诊断腹部外科疾病及选择治疗方案的可行性。

The lifetime of nylon 1010 and nylon 1010/POSS composites decreased with increasing temperature.

热重-红外联用分析表明尼龙1010在氮气气氛下的降解产物主要为小分子的低聚物，POSS并不改变尼龙1010降解产物的组成。