力的平行四边形

Composition of Forces; The parallelogram Formula; Vector; High school student

中文关键词：力的合成；平行四边形定则；矢量；中学生

If many forces are acting simultaneously in different directions on any body, the direction of its motion will not correspond with any one of the forces, but will always follow a middle course, the summary of them, what is expressed in mechanics by the diagonal of the parallelogram of forces.

如果同时有许多各种不相同的力作用于某一物体，该物体运动的方向不可能与任何一个力的运动的方向相符合；而总是平均最短的方向，即力学所说的平行四边形的对角线。

The main results gained in this dissertation are as follows:1. The vector theory which originates from parallelogram rule of velocity and force is inspected in detail.

主要研究成果如下：一、较深入地考察了起源于力和速度的平行四边形法则的向量理论。

The formula was established about calculating design parameters and technological parameters of ideal strip and bent strip in the period of forming. The thesis presented how to calculate the deformed area length and contact are radius of contact deforming between two elastic bodies on condition of the friction. The calculating formula of pinch force about plate-strip pinch mill was given and the results were analyzed that friction coefficient and radius of pinch rolls are very important for determining pinch force. Moreover, the rule of deforming and stress distribution of different 〓 ratio were gained on condition that the deforming was considered to be non-uniform distribution in the gap. The differential equations were got that calculate the displacements of large deflection of elastic cantilever rectangle plate with fixed end and the formula of the Finite Strip Method was conducted to study the regularity of mid-plane displacements, deformation and stresses for elastic-plastic large deflection bend of cantilever parallelogram plate with fixed or slidable end by integrating Prandtl-Reuss equation.

建立了一套完整的设计参数计算公式和在成型过程中理想带钢或具有月牙弯带钢的工艺参数的调整公式；在考虑摩擦力的条件下，对两弹性体接触变形过程中的接触变形区长度和接触弧半径用位移解法进行了研究，推导了板带递送机的递送力计算公式，从而得知在递送机设计过程中，应选择适当摩擦系数和辊身直径；另外，还从辊缝内带钢实际变形出发，分析了对于不同的〓值，带钢的变形规律及应力分布状况；建立了固定端悬臂矩形板弹性大挠度弯曲变形的控制方程，并且在对Prandtl-Reuss方程的积分处理的基础上，导出了固定端和滑动端悬臂平行四边形薄板的弹塑性大挠度的中面伸展位移、变形和应力的有限条元法公式，编写了Fortran语言计算程序，在各种参数条件下，对螺旋焊管成型过程变形规律进行了全面的分析研究，从而为螺旋焊管的生产和进一步的改进提供了理论依据。

Based on the theory of hanging on laneway roof with roof bolt and taking the bolt as base point, this new preceding support can work in the free space on the laneway roof, allowing other equipments such as the entry-driving machine work at the same time, thus improving the utilizing efficiency of the laneway. On the cirques track of bolts, its three groups of claw, which are driven by hydraulic force, work as fulcrums to one another to push the support move forward.

基于顶板锚杆悬挂理论，以锚杆为基点，采用自制圆形梁为执道，以液压力驱动3组机爪互为支点实现超前支架在巷道顶部空间的迈步前移，采用具有顶板适应性的变运动方向平行四边形机构作为超前支护机构，来实现超前支架的支护作业。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。