【单选题】Which of the following is NOT true about Reefer hold?
A.
Reefer is shorted for refrigerated container.
B.
Reefer holds are used to transport grain.
C.
Reefer holds are pretty gigantic.
D.
Reefer holds are often fitted with large cargo-refrigeration systems.
【单选题】Reefer holds must be pre-cooled before surveyed
A.
Reefer holds must be pre-cooled
B.
Reefer holds must be cleaned
C.
Reefer holds must be surveyed
D.
Reefer holds must be ventilated
【判断题】轴交角 δ = 90° 的直齿锥齿轮传动中,作用于两齿轮上的力有如下关系(大小齿轮齿数不等): F a1 =F a2 , F r1 =F r2 。 F r 、 F a 分别为径向力、轴向力。
【简答题】对轴交角∑=90°的直齿圆锥齿轮传动,下列传动比公式中不对的是( )。 A. B. C.i12=tanδ2 D.i12=tanδ1对轴交角∑=90°的直齿圆锥齿轮传动,下列传动比公式中不对的是( )。
【单选题】对轴交角∑=90°的直齿圆锥齿轮传动,下列传动比公式中不对的是( )。