临界速度

The truck cast steel three big piece type bogie is easy to maintain. But since the grate weight under spring and the large operation strength during running, it is difficult for the bogie to keep the positive position. The critical speed of the snaking motion is low, which is inapplicable for high speed running. The other type of truck bogie is H type integrative truss. Its structure is complicate relatively, which is not easy to manufacture and maintain. But it can keep the positive position of the bogie preferably. And because it is adopted the structure of axle box one series elastic suspend, the weight under spring reduces. Which achieve the effective control to wheel sets and improve the running quality of the bogie distinctly.

货车铸钢三大件式转向架便于制造维修，但因其簧下质量大，在运行中轮轨作用力大，转向架难以保持正位，蛇行运动临界速度低，不适用于高速运行；货车转向架的另一种形式是"H"型构架一体式，结构较为复杂，不便于制造和检修，但它能够较好地保持转向架的正位，而且由于采用了轴箱一系弹性悬挂结构，降低了簧下质量，实现了对轮对的有效控制，明显地改善了转向架的运行品质。

It has been shown that there is unstable hunting in the monorail car which inheres with the bogie structure.

分析结果表明跨坐式独轨车辆的转向架存在不稳定的蛇行运动，其临界速度取决于转向架本身的结构及参数。

From the numerical results of critical conicity calculatians for bogies with different steering stiffness and different construction parameters, the paper concludes that the low conicity instability can be reduced by means of optimizing the bogie parameters to a va...

得到不同导向刚度下产生失稳的临界踏面锥度和不同锥度下的临界速度值。研究发现，通过参数的合理匹配，可使临界锥度降至常见最小锥度以下，从而可以避免低锥度失稳，为迫导向转向架的参数设计提出了一个新的准则。

Numerical method is used to investigate the bogie's ateral stability under diverse nonlinear factors. The influence of nonlinearities and conicity on the critical speed is investigated. The nonlinear forces considered in the bogie system include creep-force between the rail and wheel, longitudinal damping and the flange contact force.

利用数值方法研究了不同非线性力作用下转向架的横向稳定性，得到轮轨饱和力、蠕滑力、纵、横向阻尼力、轮缘死区接触力、踏面斜率以及轮轨间隙对转向架系统线性、非线性临界速度的影响规律。

A linear saturated law is used to restrain flutter. The critical velocity can be improved more than 30%.

实现了颤振的主动抑制，可以将原有气动弹性系统的临界速度提高30％以上。

Adiabatic shear instability will take place when the normal component of particle velocity excesses critical value.

发生绝热剪切失稳的条件是入射速度的法向分最大于碰撞过程的临界速度。

The critical rate equation of the particles engulfment is drawn on the bases of thermodynamic conditions and relative movement of the particles against the interface.

基于两相流原理，给出了粒子进入熔体的临界条件，定量描述了考虑粒子浓度时粒子在熔体中的运动速度，建立了粒子俘获/推移的热力学条件，并在热力学条件及粒子相对于固-液界面运动的基础上，建立了粒子俘获的临界速度判据。

In this paper, the effects of factors like flotation、cooling velocity on distribution and microstructure of the material were studied under the condition of unidirectional and multidi〓tional solidification, an order of magnitude analysis was performad in order to understand the dynamics of an advancing solid/liquid interface behind a particle as well as the behavior of the particle in front of the interface, and a model of critical velocity for the pushing/engulfment transition of particles by the interface was built, the theoretic result gave a good explain to experimental one.

本文考察了在常规铸造和定向凝固条件下，浮力、冷却速度等因素对SiC颗粒分布以及材料组织的影响，分析了颗粒在凝固过程中的行为以及对界面的作用，建立了在胞状树枝晶凝固条件下枝晶对颗粒的推移/吞并临界速度模型，理论分析和实验结果基本一致。

On the basis of simulating unsteady viscous flows, coupling the structure dynamics equations, the problem of flutter is investigated for wings, empennage and wing-body configuration.On the basis, many examples, simulating the steady and unsteady viscous flows around wings, are given in this paper.

在模拟非定常粘性绕流的基础上，与颤振运动方程相耦合，分别对机翼、尾翼和组合体流固耦合现象中颤振问题进行了研究，准确求解跨音速颤振临界速度，分析它们在跨音速范围的颤振规律，并研究分析了机翼剖面形状变化对颤振速度的影响。

The results show that nonlinear dry friction between mandril and tube conduces to the self excited vibration of tube and the drawing speed is the main factor which determines whether the mandril static balance is stable.

分析结果表明，抖纹产生的主要原因是芯棒与钢管之间的非线性干摩擦力导致芯棒产生自激振动；钢管的拉拔速度及钢管表面润滑层的好坏是决定芯棒的静平衡位置是否稳定的关键因素，提高拉拔速度可将干摩擦阻尼转化为粘性阻尼，同时也使拉拔速度远离临界速度，从根本上消除抖

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。