【单选题】When a vacuum boiling evaporator works, the hot jacket water will pass over the tube stack and ___ the sea water passing through the tubes.
【单选题】Bottom blow valves are installed on auxiliary water-tube boilers to ___________.
A.
completely drain the boiler in an emergency
B.
pr sludge from forming in the drum
C.
remove floating impurities from the boiler water suce
D.
remove settled solids from the water drum
【单选题】肝细胞病变时,下列血清蛋白浓度不减少的是
【单选题】Auxiliary boilers can be classified as .
A.
water-tube natural circulation boilers
C.
water-tube forced circulation boilers
【多选题】混凝土浇筑过程中应注意的事项主要有( )。
A.
混凝土运输、浇筑及间歇时间的总和应小于其初凝时间
D.
减少水泥用量,掺加粉煤灰可防止大体积混凝土产生裂缝
【单选题】Bottom blow valves are installed on auxiliary water-tube boilers to _____.
A.
remove suspended and precipitated solids from the boiler water
B.
completely drain the boiler in an emergency situation
C.
pr hardened scale deposits in the water drum
D.
remove floating impurities from the oily water suce
【简答题】可用性的三个目标是:有效性,效率,()。