什么是制动效能因数?试分别说明领从蹄式制动器和钳盘式制动器效能因数的大小和稳定性。
查看答案
2008年9月27日16时41分,打开神舟七号载人飞船轨道舱舱门,首度实施出舱活动的航天员是().
A. 刘伯明
B. 景海鹏
C. 翟志刚
D. 杨利伟
调整好工艺技术条件可以有效降低汽耗提高蒸发效率,在实际操作中应控制好哪些工艺条件?
断路器控制柜应密封良好,内部清洁干燥,在环境温度低于(),湿度较大时应投入加热器。
A. 15℃
B. 10℃
C. 5℃
D. 0℃
A vessel is equipped with cross-connected deep tanks. In which situation should the cross-connection valve be closed? ()
A. The tanks lie above the waterline and are filled
B. The tanks are partially filled with dry cargo
C. The tanks are partially filled with liquid cargo
D. The tanks are filled and lie below the waterline