查询词典 sinusoidal wave

The numerical result shows that this method can correctly and quickly separate pure compress wave and pure shear wave from hybrid wave field with high precision, good boundary absorption, and the numerical process is stable, so it can be used to guide multi-wave multi-components seismic datum processing, and also point out that the method has difficulty to separate the coupled wave type such as surface wave.

数值模拟结果表明，该方法能够从混合波场中准确地分离出纯纵横波波场，且精度高，边界吸收效果好，计算速度快，计算过程稳定，可用于指导实际多波多分量地震资料处理，同时指出本文算法对相互耦合的波型无法实现准确分离。

The article presents the developing condition of PWM and SVPWM first.Then the theory of SVPWM is discussed in detail.The SVPWM is based on the thought of magnetic chain tracking.It makes the ideal magnetic chain circle of three-phased sysmmetry electric motor supplied by three-phased sysmmetry sine wave voltage for basis,uses the practical magnetic chain vector formed by the different switch modes of three-phased inverter to track the basic magnetic chain circle.During the course of tracking,the inverter changes the switch modes properly to form the PWM waves.Then the modulation wave of SVPWM is analyzed in detail.The modulation wave of SVPWM is implicit,but the analogous modulation wave in A-B-C axis needs to be calculated in order to expose the internal relation of SVPWM and SPWM.That is to show the implicit modulation wave of SVPWM. SVPWM actually is a transformed SPWM ruly sampled by the modulation wave which is injected by the zero prefaces based on space vectors.

本文首先对脉宽调制技术的发展现状进行了综述，在此基础上分析了电压空间矢量脉宽调制技术的发展现状；接着对空间电压矢量脉宽调制技术的基本原理进行了详细的分析和推导，SVPWM是基于磁链追踪的思想，它以三相对称正弦波电压供电下三相对称电动机定子理想磁链圆为基准，由三相逆变器不同开关模式下所形成的实际磁链矢量来追踪基准磁链圆的，在追踪的过程中，逆变器的开关模式作适当的切换，从而形成PWM波；然后详细分析了电压空间矢量脉宽调制技术的调制波，虽然SVPWM法的调制波是隐含的，但是为了揭示SVPWM法与SPWM法的内在联系，需要求出SVPWM在A-B-C坐标系上的等效调制波，也就是将SVPWM的隐含调制波显化；SVPWM实质是一种基于空间矢量在三相正弦波中注入了零序分量的调制波进行规则采样的一种变形SPWM。

In addition, the Chinese CRT TV screen points of light, depending on the magnetic field changes in the tilt, So with the need to control the current ramp, triangle wave, This is the same square wave can not ignore the role of function generator is generally automatically generate square wave, sine wave, saw tooth wave and triangular wave, etc. ladder circuit voltage waveform or equipment.

此外，如在电视机中显像管荧光屏上的光点，是靠磁场变化进行偏转的，所以需要要用锯齿波电流来控制，对于三角波，方波同样有这不可忽视的作用而函数发生器是指一般能自动产生方波、正弦波、三角波以及锯齿波阶梯波等电压波形的电路或仪器。

Based on aforementioned findings, the author disclosed China have gone through three wave of marketing since the open policy reform in the end of seventies in the last century: the first wave taken place from the end of seventies to the end of eighties of last century, during this period of time, enterprises commonly took a marketing tactics mix of unitary product, high gross-profit pricing, wholesale and information notification; the second wave happened from the end of eighties to the end of nineties in the last century, during the second wave, enterprises often took a marketing tactics mix of serialized products, medium gross profit pricing, regional distribution and advertisement on mass media; the third wave occurred from the end of nineties of last century to now, during the third wave, enterprises usually adopted a marketing tactics mix of segmented products, low gross profit pricing, outlet interception and tangible benefits promotion.

基于上述认识，本书进而揭示出，中国市场自上个世纪70年代末改革开放以来，已经经历了三次营销浪潮：第一次营销浪潮发生在20世纪70年代末至80年代末，期间，企业界普遍采取的是&单一化产品+高毛利政策+批发销售+信息告知&的链接标记营销策略组合。第二次营销浪潮发生在20世纪80年代末至90年代末，期间，企业界普遍采取的是&系列化产品+中毛利政策+区域链接标记分销+大众链接标记广告&的营销策略组合。第三次营销浪潮发生在20世纪90年代末至今，期间，企业界普遍采取的是&细分化产品+低毛利政策+链接标记终端拦截+实惠促销&的营销策略组合。

Based on aforementioned findings, the author disclosed China have gone through three wave of marketing since the open policy reform in the end of seventies in the last century: the fi rst wave taken place from the end of seventies to the end of eighties of last century, during this period of time, enterprises commonly took a marketing tactics mix of unitary product, high gross-profit pricing, wholesale and information notification; the second wave happened from the end of eighties to the end of nineties in the last century, during the second wave, enterprises often took a marketing tactics mix of serialized products, medium gross profit pricing, regional distribution and advertisement on mass media; the third wave occurred from the end of nineties of last century to now, during the third wave, enterprises usually adopted a marketing tactics mix of segmented products, low gross profit pricing, outlet interception and tangible benefits promotion.

基于上述认识，本书进而揭示出，中国市场自上个世纪70年代末改革开放以来，已经经历了三次营销浪潮：第一次营销浪潮发生在20世纪70年代末至80年代末，期间，企业界普遍采取的是&单一化产品+高毛利政策+批发销售+信息告知&的营销策略组合。第二次营销浪潮发生在20世纪80年代末至90年代末，期间，企业界普遍采取的是&系列化产品+中毛利政策+区域分销+大众广告&的营销策略组合。第三次营销浪潮发生在20世纪90年代末至今，期间，企业界普遍采取的是&细分化产品+低毛利政策+终端拦截+实惠促销&的营销策略组合。

Based on aforementioned findings, the author disclosed China have gone through three wave of marketing since the open policy reform in the end of seventies in the last century: the first wave taken place from the end of seventies to the end of eighties of last century, during this period of time, enterprises commonly took a marketing tactics mix of unitary product, high gross-profit pricing, wholesale and information notification; the second wave happened from the end of eighties to the end of nineties in the last century, during the second wave, enterprises often took a marketing tactics mix of serialized products, medium gross profit pricing, regional distribution and advertisement on mass media; the third wave occurred from the end of nineties of last century to now, during the third wave, enterprises usually adopted a marketing tactics mix of segmented products, low gross profit pricing, outlet interception and tangible benefits promotion.

基于上述认识，本书进而揭示出，中国市场自上个世纪70年代末改革开放以来，已经经历了三次营销浪潮：第一次营销浪潮发生在20世纪70年代末至80年代末，期间，企业界普遍采取的是&单一化产品+高毛利政策+批发销售+信息告知&的营销策略组合。第二次营销浪潮发生在20世纪80年代末至90年代末，期间，企业界普遍采取的是&系列化产品+中毛利政策+区域分销+大众广告&的营销策略组合。第三次营销浪潮发生在20世纪90年代末至今，期间，企业界普遍采取的是&细分化产品+低毛利政策+终端拦截+实惠促销&的营销策略组合。

Wave after succeeding in escaping make track for of seal shot once the wave met to compare his shape short and small emperor penguin, they were brave, optimism, love help other people and solidify again very intelligent, they all appreciated a wave very much of dance, they decided to help a wave after knowing wave the career of the wave.

有一次在逃脱海豹的追击后波波遇到了比他身材矮小的帝企鹅，它们勇敢、乐观、爱帮助别人并且团结又很聪明，它们都很欣赏波波的舞蹈，在知道了波波的经历后它们决定帮助波波。

In section one, by using FICE scheme and TIME-GCM, a model of trace gases and OH airglow affected by gravity wave is set up, then the propagation of nonlinear gravity wave and the effect on trace gases and OH airglow are analyzed. The result shows gravity wave excited by tropospause forcing can propagate stably to the mesosphere through the stratosphere so that energy and momentum can be transferred from one region to another. In this process, gravity wave undergoes growth, overturning, convection and breaking. And the no-isothermal structure can accelerate the breaking of gravity wave in mesospause, and the breaking of gravity wave is an important source of convection and small-scale waves.

在第一部分的工作中，利用全隐欧拉格式和全球热层-电离层-中间层-电动力学环流耦合模式，对重力波的非线性传播及其在传播过程中对中高层大气中氧族和氢族成分和与之密切相关的OH气辉辐射的影响进行了数值模拟，结果表明，从对流层向上传播的重力波经历了产生、发展、饱和、对流产生直至破碎的非线性演化，大气的非等温结构加速了重力波在中层顶区的破碎，重力波的非线性传播是小尺度对流和湍流产生的一个重要的源。

Second order incident boundary condition on fixed incident boundary is derived for numerical simulations, based on the cnoidal or sinusoidal motions of wave maker paddle, which shows that the prediction with second order incident boundary condition is more accurate than the prediction with first order incident boundary condition. 2 The analytical solution for higher-order Boussinesq equations is derived and its applicable range is discussed. 3 A 2-D fully non-linear numerical model using boundary element method is developed to obtain wave forces acting on rectangular obstacle. 4 The three-dimensional fully non-linear waves are studied in a numerical wave tank using finite element method.The studies on the coupled numerical model combined Boussinesq equations with Laplace equation are following.

非耦合非线性波浪计算模型：1 根据造波板做椭圆余弦运动或正弦运动速度，推导出数值模拟波浪水槽时固定入射边界上的二阶波浪入射边界条件，数值计算结果和实验结果的对比表明采用二阶入射边界条件对波面升高的预报比采用一阶入射边界条件对波面升高的预报更为精确；2 推导了波浪水槽造波板做正弦运动所产生波浪的高阶Boussinesq方程摄动展开解析解，讨论了该解析解的适用范围；3 对整个波浪水槽应用边界元方法数值模拟了波浪对物体的非线性作用；4 用有限元法求解三维Laplace方程模拟了三维完全非线性波浪水槽。

The main contents include the ray phenomenon and its generation conditions; the deduction and physical illumination of wave action conservation equation and wave number conservation equation; ray theory for sinusoidal waves; Fermat's principle; the variation of amplitude in the case of straight and parallel depth contours and circular depth contours; the amplitude near the caustics; wave trapping; deduction of mild-slope equation and the relevant numerical solution methods.

讲授折射现象及其发生的条件；波作用守恒方程和波数守恒方程的推导及物理解释；稳恒正弦波的控制方程及射线方程；费马原理；利用射线方程研究等深线是平行直线和圆周线时波振幅的变化，特别是焦散线附近波高的变化以及由此而产生的波的俘获；缓坡方程的推导及有关的数值求解方法。

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。