质点与质点之间由一组虚拟的切向键和法向键连结。

These mass particles were connected with virtual normal bonds and tangent bonds.

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微观上法向键和切向键的密度衰减分别决定着材料不同的宏观全过程破坏特征。

The density evolutions of normal bond and tangent bond in micro scale determined different characters of material failure in macro scale respectively.

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如果需要得到头字段键，可以向最后一个方法传递一个参数，这个参数表示在结果集中所感兴趣的项的索引。

Should you need to get the header field key, you could pass a parameter to the final method representing the index of the entry in the result set you were interested in.

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But because there's this lone pair here, it's pushing down on the other bonds, 5° so we end up with an angle of less than 109 . 5 degrees.

但因为这里有孤对，它会把其它键向下压，所以键角会小于109。

麻省理工公开课 - 化学原理课程节选

So since we have two lone pairs, we're going to be pushing down even further on the bonding electrons, so we're going to smoosh those bonds even closer together.

因为我们有了两个孤对，我们会把成键电子,更加向下压，所以我们把这些键更加紧得推到一起。

麻省理工公开课 - 化学原理课程节选

So what actually turns out the reality is that h e 2 does exist, but it exists as the weakest chemical bond known, and it wasn't, in fact, even found to exist until 1993, so I can assure you this is not a bond that you see very often in nature, and it is a very, very weak bond.

实际上He2键是存在的，但它是目前所知的最弱的键，直到1993年它才被发现，所以我可以向你们保证在,自然界你们不可能经常看到它，它是种非常非常弱得键。

麻省理工公开课 - 化学原理课程节选