Which characteristic of Halon is a disadvantage when it is used as a fire extinguishing medium?()
A. Leaves a residue
B. Cost,relative to other agents
C. Breaks down while under prolonged storage
D. Conducts electricity
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35kV架空线路跨越公路且在最大弛度时,导线对路面的最小垂直距离为()m。
A. 5.5
B. 6.0
C. 6.5
D. 7.0
当调节时间Ts一定时,对于高水头电站,导叶(阀门)的关闭规律宜采用()
A. 先快后慢
B. 先慢后快
C. 直线规律关闭
D. 与关闭规律无关