发布时间:2025-01-30 16:09:18
这个根据荷载而定,荷载小用小螺栓,荷载大用大螺栓,根据梁的大小而定。具体根据设计师设计来做!或者多上两个螺栓。
怎么把有毒的盐河盐沙滩盐过滤成无毒的盐求一简单的方法古代又是怎么提纯的
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