发布时间:2025-02-02 00:49:40
为上安装示意图,因为螺钉底部它有一个锥形,而且外壳有开几个槽,当旋紧螺母时,就会让锥面挤压外壳,外壳因有开槽,它就会向外变形,从而紧锁住墙体.
所以这并不是剪力,应该为斜面(锥面)挤压力
我想养一些中型热带鱼可我是新手所以想请问一下大家哪些鱼混养比较好看而且好养
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