扰动

With random disturbances on the inlet of the jet, axisymmetric instability appears firstly and then the large coherent structure—vortex ring is formed.

在模拟自然射流的随机扰动的条件下，射流首先出现轴对称失稳，形成大尺度拟序结构一涡环。

With enough free-surface range and collocation point number, this paper discusses the effects of the two kinds of distances on the numerical convergence, proposes the expressions for the inner distance, and has obtained consistent and convergence results.

本文研究了潜水椭球和Wigley船型的兴波问题和绕射问题，计算了非线性的兴波阻力系数、纵向一阶波浪扰动力和二阶倍频波浪扰动力，以及兴波武汉理工大学博士学位论文波形和绕射波形。

Such perturbations might be effected by square, pairwise comparison matrices, one per column of each data matrix.

这样扰动也许由正方形， pairwise 比较矩阵，一个影响每各个数据矩阵专栏。

This can be thought as a particular disturbance of the collectively compact operator introduced by Anselone.

这可视为是对Anselone所引进和研究的那类总体列紧算子的一种特殊扰动的结果。

In order to eliminate the influence caused by the nonminimum phase characteristic of a common Boost DC／DC converter, Viswanathan K has proposed a novel tristate Boost DC／DC converter. For enhancing performance, the statespace averaging model of this converter was first presented in this paper. Due to the nonlinear nature in this model, an inputoutput feedback linearization technique was adopted, and a complete controllable linear system was obtained. Then a statefeedback control strategy was designed based on this linear system. Simulation results show that the proposed control strategy can assure constant output voltage in a wide range, so as to realize the stability of the system during large fluctuation of power supply and load disturbance. Good dynamic performance can also be achieved.

针对 Viswanathan K为消除普通BOOST DC／DC变换器的非最小相位特性而提出的三态Boost DC／DC变换器，为进一步提高这种电路拓扑的性能，在建立了变换器状态空间平均模型的基础上，针对其多变量、非线性特点，采用输入输出线性化将其转化为一个完全可控的线性系统，在此基础上应用现有成熟的线性控制策略进行了控制系统的设计，并且采用MATLAB进行仿真验证，结果表明：这种非线性控制策略可以确保输出电压在大范围内恒定可调，且即使存在大范围扰动(输入电压和负载变化均较大)的情况下，系统也可以确保稳定性和良好的动态性能。

When the parameters of complex system are variable by time, it is more difficult to design the control system.

时滞特性是工业生产过程中普遍存在的现象，由于时滞现象的存在，扰动不能被及时察觉，控制作用需长时间后才能反映到系统输出上，因此使控制器参数不易选取，若控制参数调整不当，会造成系统控制品质的下降，严重时会导致系统不稳定。

Thus it is shown there may be dissipative compressional wave and shead wave in viscous compressible fluid.

本文在小扰动条件下，从粘性可压缩流体的运动方程、状态方程以及连续性方程导出了它的波动方程，从而表明粘性可压缩流体中能够存在有耗损的纵波与横波。

Based on the integrated compressible fluid mechanics equations,using eigen value analysis,the new method of non-reflecting boundary condition was proposed for aeroacoustics simulation of disturbance in shear flows.

基于完整的可压缩流体力学方程，利用特征分析的方法给出了气动声学中数值计算扰动的边界处理方法。

Comparison between Rayleigh-Taylor instability growth rates of compressible and incompressible fluid was made, with the state equation of compressible fluid in an arbitrary function form of density and pressure.

对比研究了可压缩与不可压缩流体的Rayleigh-Taylor不稳定性小扰动阶段的增长速率，其中，压力是密度的任意单值函数，这个函数也即是可压缩流体的状态方程。

Results show that existence from strong convergence of water vapor and the conditional convective instability in the middle and low troposphere probably provided the suitable environment for heavy rainfall.

分析表明，对流层中低层水汽的大量集中以及对流不稳定条件的存在可能对此类系统发展提供了有利环境，对其启动的机制作了初步的讨论，认为地形的动力强迫和地面冷锋以及低空急流扰动可能对此类系统的发生发展起了触发作用。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。