查询词典 impact force

The modal tests of PCB and PCB assembly (free boundary condition and fixed boundary condition) were carried out. The equivalent elastic modulus and damping parameters of PCB can be gained, and the fixed boundary condition of finite element model was also determined. These will help to the following work. Second, drop impact tests of three different heights were carried out. Strains and acceleration responses of PCB were measured. Failed BGA packages of different test conditions were dyeing, and cross section analysis of failed solder joints was conducted. It was found in our drop tests that the root cause of lead-free solder joints under drop impact was the combined effect of mechanical shock and PCB bending vibration.

针对JEDEC标准试件的局限性，提出了设计便于统计学研究焊点可靠性的试验试件的构想，利用有限元模态分析方法确定并验证了用圆形PCB组件替代JEDEC标准试件的可行性；通过一系列模态试验和有限元模态分析，确定了圆形PCB组件的相关试验参数，这不仅为跌落碰撞下PCB组件有限元模拟确定了较为合理准确的有限元模型，而且为正确地评价跌落碰撞下PCB组件的可靠性问题奠定了基础。

Micro-computer monitors work inside the electron gun to emit electronic, through the acceleration of high-voltage electrode, adjust shooting at the screen, the screen of fluorescent material by high-speed electronic flow impact, resulting in X-ray, scientific evidence shows that more than 20 of each year only Guoqin dose of radiation, will constitute a harm to humans, operate microcomputer year will not be more than 0.3 Roentgen of exposure; even when engaged in computer work for 30 years, the cumulative exposure will not be sufficient to cause human injury lowest half, but during early pregnancy (the first 3 months) the fetus is in a cell division, organ differentiation sensitive period, or should be:(1) hours of work per week is not more than 20 hours (2) one meter away from the computer (3) wearing protective skirt (4) work completed Huanyi bath in order to reduce the electromagnetic radiation on the impact of the fetus.

微电脑显示器工作时，内部的电子枪发射出电子来，经过高压电极的加速，调整射向荧光屏，屏幕上的荧光物质受到高速电子流的撞击，产生X射线，科学论证表明，每年只有超过20论琴的剂量照射，才构成对人体的伤害、操作微机一年也不会超过0.3伦琴的照射量；即使从事微机工作30年，累积的照射量也不足以造成人体损伤最低值的一半，不过妊娠早期(头3个月)胎儿正处于细胞分裂，器官分化的敏感时期，还是应当：(1)每周工作不超过20小时(2)距电脑一米开外(3)穿防护裙(4)工作完毕洗澡换衣，以减少电磁辐射对胎儿的影响。

The analytical and experimental system for the responses of blade under the bird impact, which can be used in the design of the resistance of new fan or compressor blades to FOD on the bird impact, is established in the research work of this paper.

本文开展的叶片鸟撞击瞬态响应计算与试验研究，在国内属首次进行。这些研究工作建立了较为完整的叶片鸟撞击瞬态响应分析系统，可供进行叶片抗外物损伤设计时应用。

Cold air was the factor of synoptic system that producing maximal effect on acid rain, followed by low pressure trough, especially the westpath frontolysis and low pressure trough in South China Sea, which have very obvious impact. Subtropical high pressure has a low impact to acid rain.

对酸雨影响最大的是冷空气，其次是低压槽，其中以西路锋消和南海低压槽影响较为明显，副热带高压影响较小。

B Through theoretical and experimental studies, the paper investigats the relationships between hammer geometer and stress waveform generated by the hammer. After the mechanical meanings of linear model used by others are demonstrated, a simple expression of rigidity of an equivalent spring for direct impact between a hammer and a rod is obtained. Based on the above work, a mathematical model and numerical method for the impact of the hammer with progressively changing cross-section on the rod are presented.

2应用理论分析和实验研究相结合的方法，探讨了冲击应力波波形和冲锤形状尺寸之间的关系；阐明了冲锤与杆撞击局部变形的线性模型的物理意义，继而分析讨论了冲锤端头曲率半径与撞击弹簧刚度的关系；在此基础上，提出了连续变截面冲锤与杆撞击的数学模型和计算方法。

"Impact","His return to the country will make a great impact on the political circle.

1，他的回国将对政界产生很大的影响。

Consists of groundwood papers which are used in forms manufactured for use in data processing machines. This grade may contain coloured stripes and impact or non impact computer printing.

含磨木浆的计算机用纸：用于数据处理机的表格纸，允许掺有一定数量的经过表面处理的纸张。

The invention relates to a vertical rotor mill, especially to an impact pulverizer or to a hammer mill for grinding granular material using impact tools.

本发明涉及一种竖直旋转体粉碎机，特别是一种冲击式粉碎机或一种锤式粉碎机，用于通过冲击工具(8)粉碎颗粒状材料。

The problem is impact bias, the tendency to overestimate the "hedonic impact" of future events.

问题在于影响偏差，一种过高估计未来时间的享乐影响力。

It is not hierarchic, so I do not think the arrests or the killings of its senior officials have ever had any impact, any significant impact on the movement.

这不是等级，所以我不认为逮捕或杀害其高级官员有过任何影响，任何对运动产生重大影响。

Methods Clinical data of 3 cases of bile duct injury during laparoscopic cholecystectomy were analyzed retrospectively.

回顾总结3例LC术中胆管损伤的临床资料，分析3例胆管损伤的原因及对策。

These techniques are applied to the gobang.

本文将这些技术用于五子棋中。