查询词典 harmonic wave

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。

The square wave or corrected sine wave auto inverters have many limitations. When supplying to inductive load (such as electric fan, electric drill etc.), a square wave or corrected sine wave auto inverter produces too much harmonic current which makes the load seriously heated and even damaged. When supplying to capacitive load or rectificative load such as notebook PC, mobile phone charger etc.

方波或修正正弦波电源有很多局限性：在为感性负载供电时产生大量谐波电流，导致电器严重发热，甚至损坏；为容性或整流性负载（笔记本电脑、手机充电器等）供电时产生严重的脉冲电流，严重时可能导致电器损坏。

As response signal of damped free vibration could be considered as product of the harmonic wave and the unilateral exponential function and the rectangle window, the peak frequency and phase are frequency and phase of the harmonic wave signal is proved in theory in this paper.

针对自由衰减振动信号的连续谱，将其看成无限长谐波信号与单边指数函数及矩形窗的乘积，在理论上证明峰值点的频率和相位就是信号的实际频率和相位。

Both approximate and calculated results of fundamental wave and second harmonic wave for intensity variation with phase aberrated coefficient have been presented. It is applicable to designs of harmonic generation for high power lasers.

第三部分：把准晶态结构引入到非线性光学介质中，得到所谓的超晶格，当这种超晶格的倒格矢与光波矢可以相比拟时，光波在其内的传播将与传统情况有很大的不同。

Liapunov—Schmidt method is one of the most important method in the bifurcation theory.

Liapunov—Schmidt方法是分叉理论的最重要方法之一。

Be courteous -- even when people are most discourteous to you .

要有礼貌──即使当別人对你最不礼貌的时候。