Working principle and structural features of SYZX 75 wire - line coring hydro - hammer are presented.介绍了SYZX75型绳索取心液动潜孔锤的工作原理及结构特点.A worker's arm was injured whilst operating a concrete coring machine.工人在操作混凝土钻孔机时引致...
火箭发动机的作用是瞬间的, 在适当的地方燃烧推进物生成 高速 粒子.A rocket motor's'bullets'are minute, high - speed particles produced by burning propellants in a suitable chamber.一种蓝色透明、有磁性的液体,由压缩气态氧获得,用作火箭推进物中的氧化剂.A two - component roc...