查询词典 variable-density system

In chapter 4, the application of synthetic variable structure control theory to the multivariable electric transmission system is studied.

第四章对复合变结构控制在多变量电气传动系统中的应用进行研究。

The neuralgic center of the "Hub" is the Arena, central space of convergence equipped with a modular system of curtains, furniture, collapsible tiers for a variable configuration.

该"中心"是竞技场的中枢，与一个窗帘，家具，可折叠层的变量配置的模块化系统配备衔接的中央空间。

A curve coordinate system which is suitable for variable height curved box-girder were established.

当曲轴线半径与箱梁宽度比小于10时，必须考虑曲率沿横向变化的影响。3。

As a result, it shows thatthe static or dynamic subsystem optimum alone is not equal to the system optimum. Three initial value problems met in the optimal design of flying vehicle are studied andconclusions are derived that: orthogonal test method can be adopted to decide the initial valueof static optimization problem, some mathematical techniques can be used to deal with thecostate variables of Maximum Principle and decide the initial value of the costate variable,the indirect method can be used to get the analytical solution under ideal case to guide thechoice of the initial control curve in the direct method. With some numerical examples oftrajectory optimization, it shows that all these methods are useful not only in accelerating theconvergence but also in converging to the global optimum.

针对飞行器优化设计中的三种初始值问题进行了研究，以远程弹道导弹弹道的工程优化为例说明，对于静态优化问题，采用正交试验法选取初始值，不仅可以大大加快收敛的速度，而且更有可能收敛到全局最优解；以气动力辅助变轨问题为例说明，用共态变量的一阶泰勒级数展开可以解决极大值原理中共态变量初值难于确定的问题；以二级弹道导弹的主动段弹道优化为例说明，利用间接法在理想情况下得到的解析解来指导直接法初始控制曲线的选择，将大大有利于提高直接法的收敛速度。

Based on description method of damping motion in mechanical vibration, variables movement of generator are divided into two basic motion models: damping oscillation and critical damping motion. Detail methods of extracting damping parameters from simulation data is introduced to establish variable motion models. An approximate method is put forward to simulate low-frequency signal and generator response characteristic, from which motion models and damping parameters of main variables are obtained. The influences of oscillation amplitude, frequency and initial operating point of power system to the motion damping parameters are analyzed.

借鉴机械振动中阻尼运动的描述方法，将低频振荡下发电机主要变量的运动归纳为阻尼振荡和临界阻尼两种基本运动形态；介绍了从仿真数据提取阻尼参数建立参数运动模型的方法，实现对发电机振荡特性的量化分析；提出一种系统侧低频振荡信号的近似模拟方法，并应用于发电机响应仿真，获得了主要变量的运动模型和阻尼参数；分析了系统侧振荡幅度、频率以及初始工况对发电机功角振荡的影响。

We have set up a system which can measure thermoelectric powers at low temperatures in a 4He variable temperature cryostat.

我们在4He降温系统下，架设了一个可以量测热电势的样品座。

The crystallization speed is variable with the changing of temperature and pH in the system.

沥青铀矿的结晶速度在不同的温度和pH条件下是不同的。

Based on application of 3D body-fitted numerical grid with a curvilinear coordinates system and the theories about turbulent flow and the laminar flow, the new techniques that the independent variables were expressed by co-variable velocities were applied to solve the problems about flow around a high-speed car body for the first time.

采用当今数值新技术，较为全面和深入地研究了高速汽车车身绕流问题。本文依据k-ε双方程湍流模型和附面层理论，采用先进的曲线坐标系下的贴体与边界正交数值网格技术，首次把以协变速度分量作为独立变量的数值技术运用于汽车车身绕流问题的求解。

By considering torque characteristics of variable-frequency motors and mesh stiffness as well as backlash nonlinearity in gear transmission,a dynamics model for the cutting system of shield tunneling machine with redundant drives was established. The fluctuation characteristics of torque loads and dynamic cutterhead driving torque in composite strata were analyzed.

复合地层掘进扭矩载荷突变是造成盾构机掘进过程中堵转停机的直接原因，考虑盾构机刀盘驱动变频调速电机特性、转矩传递过程中齿轮啮合刚度及齿侧间隙等非线性因素，建立冗余驱动的盾构机刀盘切削系统机电耦合动力学模型；针对典型复合地层地质条件，对盾构机在上软下硬地层掘进过程中刀盘驱动转矩动态特性进行仿真分析。

In the paper,by using Fourier Series,basic harmonic balancing approximation and optimum numerical iterration,the response computation of a two-degrees-of-freedom dry friction damped vibration absorber system with velocith-dependent variable coefficient of sliding friction under harmonic excitation is discussed.

研究了两自由度滑动摩擦系数随相对速度变化的干摩擦吸振系统简谐激励响应计算问题，提出了最优化处理方法，并推导了相应的迭代方程。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。