当无缝线路钢轨折断,断缝大于50mm时,应立即进行紧急处理。
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Increasing the valve clearance between a valve stem and rocker arm, will result in the valve ()
A. closing later
B. opening sooner
C. staying open for a shorter period of time
D. staying open for a longer period of time
顶部采光是在屋顶处设置天窗,顶部采光率比侧窗低,但其构造简单,造价较低。
A. 正确
B. 错误
巷道瓦斯浓度超过()时,由通风部门编制措施,矿总工程师批准,并组织排放。
A. 0.01
B. 0.015
C. 0.02
D. 0.03