何为主保护?
参考答案:
是指发生短路故障时,能满足系统稳定及设备安全的基本要求,首先动作于跳闸,有选择地切除被保护设备和全线路故障的保护。
---- Good morning, Hilton Hotel.
---- Hello, I’d like to book a room for three nights.
----__________
A.Can I help you?
B.Just a minute, please.
C.What’s the matter with you?
D.At your service.
KNO3的溶解度在t1℃时为50g,t2℃时为30g,若将t1℃时KNO3饱和溶液冷却到t2℃时,有24gKNO3晶体析出,则原饱和溶液是()克。
A.1800
B.180
C.18
D.1.8