摩擦力

This paper described several applicable measurement techniques and characteri-stics in the study of Spacer grid clipping force relaxation behaviour,such asmeasuring clipping force relaxation in the laboratory,measuring fuel rod brea-kaway force and withdrawal force within the cell of post-irradiated 17×17 asse-mbly,measuring friction force and cell size withi...

本文介绍了定位格架夹持力辐照松弛研究中几种适用的测量方法及其特点，如在实验室研究中测定位格架弹簧力的松弛，在辐照后的17×17验证组件中测燃料棒在栅元中的移动力和滑动力、在抽出燃料棒的空栅元中测栅元摩擦力及栅元尺寸等方法。

The test equipment, installation and test principle of gigacycle friction fatigue were introduced in this paper,On the basis of the fatigue test apparatus of 20 KHz ultrasonic vibration,the frequency value,the dimension calculation formulas and the specific shape of the specimen were given.

介绍了高周摩擦疲劳试验设备、装置及试验原理根据 2 0 0 0 0Hz超声波震动疲劳试验机的要求，给出了试件的频率值、尺寸计算、公式和具体形状；最后，给出了摩擦力、应力与位移的表达形式和疲劳寿命的记录方

Also, it's better to use a less grit uhm, on your nail file.

还有，这会更好用更少的的摩擦力在你的指甲钳。

The main results of the investigation are as following:(1) Some important criteria for the design of multi-layer structure are acquired: the ratio of the layer thickness to the contact diameter should be controlled to a value about 0.8; increasing the number of the gradient layers and elasticity modulus of the top layer would benefit to the yield strength and the stress status at the interface.（2）By means of molecular dynamics simulations for a indentation and sliding process, it is discovered that dislocations of 45 direction to the surface occur in the surfaces layer, which is correspond to the direction of the plastic flows observed in the macroscopic continuous medium. The irreversible deformation caused by the dislocation and the atom piles at the surface are responsible for the irreversibility of the force response. They are also the main factors for the friction generation. The temperature and the indentation velocity have significant effects on the deformation behaviors of the material of the surface layer. The yield strength would increase obviously if the indentation velocity is greater than 10 m/s.（3）A method to evaluate the fracture toughness of coating by estimating the crack-density functionβof a Wicker''s indentation was proposed. Meanwhile a new surface treatment technology was developed using non-equilibrium plasma.（4）A MD-FE hybrid method and corresponding software was developed to analysis the tribological behaviors for multiplayer system.

研究主要内容和结果有：（1）得到指导梯度膜设计的几个准则：控制膜层厚度与接触半径比在0.8左右为宜；适当增加梯度层层数和顶层弹性模量，有利于提高抗屈服能力和改善界面处的应力状态；（2）通过对嵌入和滑动摩擦过程的分子动力学模拟，发现表层产生一个与宏观连续介质的塑性流动方向观测一致的45 方向位错；位错造成的不可逆变形和表面的原子堆积，是力的响应不可逆性的原因，也是构成摩擦力的主要因素；温度和嵌入速度对材料变形特性有显著的影响，当嵌入速度大于10 m/s时，屈服强度明显增加；（3）提出压痕裂纹密度系数β半定量判定膜层断裂韧性的方法；并开发出表面强化新工艺；（4）开发出分析表面摩擦学特性的MD-FE复合模拟方法和相应模拟软件。

In a theoretically friction less, or ideal, machine, the work input and work output are equal, and the efficiency would be 1, or 100%.

理论上，一个无摩擦力的，或者说是理想的机器，输入和输出的功相等，因此效率是1，或者说是100%。

Nature, gravity, elasticity, friction, magnetic, electrical, power and other inertial force.

自然界有重力、弹力、摩擦力、磁力、电力、惯性力等各种力。

The method utilizes the friction force between the object to be moved and the fixed base plane, and the reaction of the inertial force caused by a dynamic rapid deformation of a piezoelectric element.

这种方法是利用移动体与固定的基平面之间的摩擦力以及由压电元件动态的急速变形所产生的惯性力的反作用力来产生精确运动的。

Four-node degenerated shell element and rigid shell element are used in our FEM model.Updated Lagrange formulation and rate form constitutive equation are adopted to solve the problem of large strain and large rotation in sheet forming process.Sheet metal material property is described by plastic anisotropy yielding model and isotropic hardening model.Master surface-slave surface contact model is used to define the contact between tools and blank.Contact constraints are enforced with a kinematic algorithm and friction stress is computed by Coulomb friction law.Dynamic relaxation method is used to treat springback after forming stroke.

四结点蜕化壳单元和刚体壳单元分别用来建立板和模具的有限元模型；更新Lagrange法和速率型本构关系被用来处理板料变形中的大应变和大转动；材料模型采用塑性各向异性屈服与等向强化模型；通过主从面模型定义板料和模具的接触，接触算法采用运动约束法，摩擦力用库仓定律计算；并利用动力松弛法对回弹过程进行了计算。

For the sake of accurately estimating the contact force, we describe a new method, in which the contact force is considered as a jump function of time, and by use of response to jump function, the history of impact force is detected in the duration of rotor contacting with stator.

为更准确地获得接触作用力，本文将接触过程中转子所受作用反力函数视为在微小时间间隔下的阶跃函数，提出一种计算接触作用力的新模型，利用系统对阶跃函数的响应可以得到转子与定子碰摩时的切向摩擦力与法相作用力的时间历程及相应的位移、速度量。

It obeys the rule of gravity and the rules of kinetic energy and friction which slow it down.

它遵守重力定律和能量守恒定律以及让它减速的摩擦力定律。

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。