脉动

The power system forced oscillation introduced by anharmonic periodic disturbances is then discussed. The effect of complicated pressure pulsation, ballistic pressure pulsation and quasiperiodic pressure pulsation on the stability of power system based on a single machine infinite bus power system and multi-machine power system are analyzed respectively through simulation.

从理论上探讨非简谐周期性扰动下的电力系统强迫振荡，并通过时域仿真分析单机无穷大系统和多机系统中汽轮机复杂压力脉动、准周期压力脉动及冲击性压力脉动对电力系统稳定性的影响。

The results show that the equiaxed zone ratio of the casting billet is greatly increased,with its soidification structure is obviously improved,and the momentum values of the electromagnetic forces both parallel to and perpendicular to the direction of the traveling magnetic field pulsate periodically with time.

采用三相通入不同电流的非平衡线性电磁搅拌技术进行了铸坯的静态浇铸实验，并对电磁搅拌过程中钢液内的电磁力各分量的瞬时值进行了理论分析·结果表明，当采用将电磁搅拌器的三相通入不同电流的非平衡线性电磁搅拌时，在钢液内所产生的电磁力是脉动的，其大小呈周期性变化，尤其是垂直于磁场运动方向上的电磁力，其脉动的幅度很大·由此认为，当采用将搅拌器的三相通入不同电流的非平衡线性电磁搅拌时，所产生的垂直于磁场运动方向上的脉动电磁力是提高等轴晶比率，改善铸坯凝固组织的一个重要原

The influences of relevant parameters such as mass velocity, heat flux, pressure, inlet subcooling, and compressible volume on the threshold, period and amplitude of oscillation were studied.

分别研究了压力降脉动和密度波脉动的特征、脉动机理及其有关参数，如质量流速、系统压力、过冷度、可压缩容积、热负荷等参数对脉动界限值、周期和振幅的影响。

In this paper,the effect of over big pulsating voltage is described,the formation of pulsating voltage is analyzed.

过大的脉动电压造成发电机部件的危害和影响，分析脉动电压的形成，重点论述设计和制造中如何控制脉动电压，以

On the base of the mathematic model of the PMSM, the reasons of the torque pulsation are analyzed. Then the validity of Iterative Learning Control in torque ripple minimization is expatiated. A whole simulation model is developed using SIMPOWER, and the effective of ILC in torque suppressing is proved. The scheme for hardware and software of integrated PMSM are demonstrated in the thesis.

本文在永磁同步电机数学模型的基础上，总结分析了永磁同步电机转矩脉动产生的原因，引入迭代学习控制抑制转矩脉动，利用SIMPOWER工具箱建立了永磁同步电机控制系统的仿真模型，对PMSM控制系统进行了仿真，仿真结果证明迭代学习控制能有效地抑制转矩脉动。

The torque ripple in SRM are relatively higher compared to induction machines. In this paper, based on the experimental data of static torque characteristic, a fuzzy-neural network is applied to learning it's inverse model off line, then according to the predefined torque distribute function, optimal current profile is real-time gained by the FNN on line, which results in a linear, decoupled, low ripple control of torque. The performances of the proposed method is demonstrated by computer simulation results.

与传统交、直流电机相比，SRM的一个最突出的缺点是其驱动系统转矩脉动比较严重，为此，论文提出了一种基于模糊神经网络转矩逆模型的SRM转矩控制方案，并设计了SRM滑模电流控制器，理论分析和仿真结果表明，基于滑模电流控制器的SRM电动机转矩逆模型控制策略能够有效的解耦、补偿和抵消SRM非线性转矩脉动特性，有效的控制SRM相转矩按期望相转矩变化，从而实现了SRM高性能、低脉动转矩控制。

The purpose of opening the orifice was to sluice. The influence of fluctuating pressure upon the dam was another problem which was concerned by engineer. The paper analyzed Shuangkoudu masonry arch dam. The result indicated that the dam natural frequencies which consider the dam and the reservoir water interaction have great different from the preponderant frequencies of fluctuating pressure, the dam's first rank of vibration was far away from the high energy region of the fluctuating flow, so the sympathetic vibration would not take place.

坝身开设孔口主要目的是为了泄洪，泄洪时水流脉动压力对坝体结构动的影响是设计人员关心的另一课题，论文针对双口渡浆砌石拱坝进行了分析，研究结果表明：在考虑坝体一库水相互作用时坝体自振频率和水流脉动压力的优势频率相差较大，坝体的一阶振动远离脉动水流的高能量范围，二者不会发生共振。

Experimental investigations on pulsant behaviors of particle flow were carried out on a two-dimensional spouted bed using PIV .

本文基于 PIV 处理颗粒流动图像获得了颗粒流动的瞬时速度；基于功率谱密度分布对瞬时速度的分析结果表明，喷射区轴线的中下部颗粒存在较强的速度脉动，环隙区颗粒速度脉动较弱；研究发现喷动周期与床体压力脉动周期基本一致。

The parameters of pulse combustor such asfrequency,length of feed tube drying tube effecting on drying property were analyzed.It ispropitious to dry high surface-water containing,small granule or liquid materials.

分析了脉动燃烧器频率、热负荷、干燥管长等参数对干燥性能的影响；发现脉动燃烧器尾管内干燥更适合于含表面水高的小颗粒物料或液体物料，可充分利用脉动气流和声波能的作用，使物料分散雾化，增大表面积，提高干燥效率；研究了脉动燃烧器尾管内干燥颗粒物料的传热特性，并将试验结果与其它类型的干燥器进行了比较。

Based on Wavelet Packet Analysis and Smoothed Pseudo Wigner-Ville Distribution, the experiment data is time-frequency analyzed. The experimental results indicate that the amplitude of the laser-induced acoustic waves increases with the laser energy; the frequency coverage is from 0 to 150 KHz, and in the meantime there is a peak located at about 25 KHz. In addition, the spectrum and the peak of frequency are basically stable in spite of the change of laser energy and target texture.

从基本的空泡动力学理论出发，推导了空泡各特征参量之间的关系，进而对空泡动力学模型进行了修正；采用有限差分法对空泡脉动进行数值模拟，得到了空泡脉动特性随液体粘性、空泡含气量、表面张力以及可压缩性的变化规律；实验上采用光偏转测试装置探测了激光空泡脉动以及空泡溃灭的细节过程，进而分析了液体粘性和作用激光能量对空泡脉动周期、泡半径及泡能等特征参数的影响。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。