【单选题】Which system(s) in the hydraulic systems of crane always hold(s) single side of load?
B.
hoisting system and luffing system
C.
hoisting system and slew and slewing system
【判断题】Paint事件的参数中可以有Graphics对象
【单选题】For a balanced three-phase △ -connected load, the average power absorbed by the load is P . Change the △ -connected load to Y-connected load, the power will :
【单选题】The slender column is under axial compressive load P, the critical load 【图片】is independent of ( ).
A.
the material of the column
B.
the length of the column
C.
the magnitude of the P
D.
the shape and dimension of the cross section of the column
【单选题】The vessel’s load line certificate is always issued by ____.
A.
The register of shipping
D.
maritime safety administration
【单选题】One should always be careful with _ (load) guns.
【单选题】The vessel’s load line certificate is always issued by ____.
A.
the register of shipping
D.
maritime safety administration
【单选题】The load on the crosshead pin is always ______, so it is the ______ half of the bearing which is subject to wear.
【单选题】The vessel’s Load Line Certificate is always issued by ().
A.
The Register of Shipping
D.
Maritime Safety Administration