脉动理论

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。

Based on fluid network theory ,the mathematical model of fluid pulsation attenuator was established.

采用流体网络理论方法对流体网络的特点和基本参数法进行分析，研究并建立一种流体脉动衰减器的数学模型，并通过脉动衰减器的阻抗及系统插入损失，对其性能进行研究。

This paper discusses the principle of the torque ripple of BLDCM with focuses on the theoretical analysis of the relationships between torque ripple and parameters of windings,motor speed and bus voltage,as well as 3-phase reverse electrodynamic potential during phase converting.

对永磁无刷直流电机的换相转矩脉动的产生机制进行了分析，主要从理论上探讨了换相引起的转矩脉动与电机绕组的参数、换相期间的三相反电动势、电机的运行速度及母线直流电压等之间的关系。

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 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。

Through the theory analyse, we gave the concept of broad sense and the formula of drag force, then analysed main facts of drag force; based on existing experiment datas and theory results, the thesis discussed calculate method for hydrodynamic pressure and pulsating pressure which effect on soleplate, at the same time, based on special structure of local material dam overshot spillway and essentiality of safe flowing, we gave advice on fixing parameter.

通过理论分析，提出了广义拖曳力的概念并推导出拖曳力的计算公式，分析了影响拖曳力的主要因素；根据已有的试验资料及理论成果对作用于底板的动水压力和脉动压力的确定方法进行了探讨，并依据当地材料坝坝体溢洪道的结构特殊性和泄水安全的重要性，对有关参数的合理取值提出了建议。

2Theory of pulse combustion was analyzed and its mechanism were discussed with planewave transferring theory in the thesis.Models of pulse combustor were reviewed and analyzed.Theone-dimensional unsteady nonlinear model of pulse combustor was simplified with lineal method.The phase relation between pulse pressure and combustion heat discharge which may prompt ordamp pulse combustion process were discussed.

对脉动燃烧理论进行了分析探讨，从平面波的传递理论出发，分析了脉动燃烧的机理；在归纳综合现有的脉动燃烧器理论模型的基础上，采用线性化分析方法，对一维非线性脉动燃烧器理论模型进行了简化，并定性分析了脉动压力与燃烧放热之间的相位关系对脉动燃烧过程的激励和阻尼作用。

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。

The article starts with the principle of pulse combustion heating furnace, on the basis of mastering the theory of pulse combustion, do research on the basic structure and principle and provide zero-dimensional thermal model of heating furnace system.

本文从脉动燃烧加热炉工作原理入手，在掌握脉动燃烧理论基础上，研究脉动燃烧加热炉基本结构和工作原理，给出加热炉系统零维热力模型。

On the basis of the mechanism of dust collection by fog-drop and the theory of turbulance pulsation,an industrial test was made on the effect of a wet vibrating fibre-grid dust-removing and cleaning device.

根据雾滴捕尘原理和紊流脉动理论，对湿式振动纤维栅除尘净化装置的效果进行了工业试验。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。