气孔率指在射线底片有效长度范围内,()占焊接接头投影面积的百分比
参考答案:气孔投影面积
汉译英:“毛重;净重;皮重”,正确的翻译为()
A.gross weight;clean weight;tare weight
B.total weight;clean weight;conditioned weight
C.gross weight;net weight;tare weight
D.total weight;net weight;conditioned weight
清理机头时,采煤机、运输机要停电闭锁,转载机不须闭锁。