英语翻译For 4 CO-planar contacts,Nguyen 171 gave a geometrictest for form-closure’ and showed how to check form closureby drawing a quadrilateral covering the overlapping conesformed by pairs of force vec
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进进出出 PS：我觉得没有那么简单..
楼主在哪里看到的?告知的话,方便探查是否有特定含义...
..科技文?数学?化学?物理?- -不是很了解……
Nguyen人名吧...