无阻尼波

Based on the equation of the model, the acceleration, displacement and story shear of a seven- story building with a three-story appurtenant structure under three control systems including only rubber-bearing base, rubber-bearing and damper and no rubber-bearing are computed under the earthquake record of 1940 EI- Centrol, respectively.

根据控制系统方程，在无橡胶垫、仅设橡胶垫和同时布置橡胶垫和阻尼器的三种工况下，运用1940EI-Centrol加速度波，对具有三层裙房的七层建筑结构进行了分析，得到了七层建筑的加速度、位移和楼层剪力等参数。

A novel hybrid active power filterwith series resonance circuit turned at fundamental frequency is proposed,which is composed of high-capacity passive power filtersfor harmonic currents suppression as well as reactive power compensation and an active power filterfor improving filtering performance as well as overcoming resonance problem due to PPFs.

提出一种基波串联谐振式混合型有源滤波器，利用大容量无源滤波器实现谐波抑制和无功补偿；采用有源滤波器改善系统滤波效果并阻尼无源滤波器与系统阻抗之间的串、并联谐振。

In order to overcome the difficulty in estimating the ripple component on dc-side capacitor reference voltage, the modified control algorithm is proposed by ignoring the ripple component. Furthermore, the relation between control performance and damping coefficient is researched. In addition, the reasons of voltage source converter inner-loop control overmodulation are also analyzed. Based on the relation between control performance and VSC inner-loop input saturation, damping coefficient is adjusted on-line by fuzzy logic reasoning so that the trade-off between control accuracy and limitation of VSC inner-loop control overmodulation is solved preferably.

由于在线计算直流电容指令电压波动量十分困难，在控制方法的执行中忽略波动量的影响，简化了控制方法的实现；此外，该方法还研究了所注入的阻尼大小对控制效果的影响以及APF内层控制过调制产生的原因，针对无源性控制律跟踪精度的要求与内层控制过调制限幅条件间的矛盾，通过构造模糊逻辑推理环节实现阻尼系数的在线调整，在满足内层控制限幅条件下确保跟踪精度和补偿效果。

It is found thatthere exist three modes in a magnetized, homogeneous, and collisional dusty plasma:the wholly damped mode due to the thermal diffusion, damped electrostatic dustacoustic wave, and damped electrostatic dust cyclotron wavediscovered by the dissertation for the first time; As neutral gas pressure increases,the damping rates of the EDA and EDC waves increase; The effects of dust densityon the EDA and EDC waves are remarkably different from unmagnetized orcollisionless plasma; A possible explanation to plasma crystallization is suggestedon the basis of the present results.

EDA的阻尼速度随中性气体压强的增大而增大，这一点与实验相符，对于EDC也存在同样的关系。尘粒密度对EDA波和EDC波的影响明显不同于非磁化或者无碰撞尘埃等离子体中的情况。当忽略碰撞时，阻尼的EDA和EDC波回到纯振荡波。最后就尘埃等离子体晶化给出了一个可能的解释。

I am sure after a few weeks of adaptation and familiarization I will have no difficulty in functioning on a daily basis in an English speaking society or in participating fully in graduate studies.

在大学的三年的学习生活不仅给予我自身的充实，更重要的是磨练和培养了我较强的自觉能力和严谨，踏实的作风以及不怕困难的精神，对未来充满了信心！

As the first volcanoes erupted, one of the gases that bellowed out was steam.

在第一批火山喷发时，喷出的气体之一就是水蒸汽。