【多选题】以下哪些情况需要对废旧制冷剂回收( )
A.
制冷装置发动故障,需要通过拆换零部件或者拆卸零部件维修
B.
制冷装置存在部分泄漏,需要通过气密性实验查找漏点
【简答题】A.He can't sleep at night. B.He can't find a quiet place to study. C.He can't narrow down his research topic. D.He can't find enough information for his research paper.
【多选题】在以下哪些情况下需要对制动系统排空( ) 。
【判断题】当RLC串联电路发生谐振时,电路中的电流将达到其最大值。串联谐振阻抗最小电流最大,并联谐振相反
【单选题】除 RNA 复制外,属于 RNA 生物合成的还有
【单选题】下述对于LTE帧结构类型1描述错误的是()
【单选题】In a narrow channel or fairway when overtaking can take place only if the vessel to be over-taken has to take action to permit safe passing, the vessel intending to overtake shall indicate her intenti...
A.
the vessel to be overtaken shall sound appropriate signal first
B.
the overtaking vessel shall sound appropriate signal first
C.
the overtaking vessel shall take action to permit safe passing
D.
the vessel to be overtaken shall take action to permit safe passing before hearing appropriate signal
【多选题】电动机与减速机联轴器的检查要点有哪些?
A.
在断开主电源的情况下,使用棉纱或百洁布等清洁电动机与减速机联轴器,应表面整洁,无积尘、油污、杂质等(永磁同步无齿轮曳引机,不适用)
B.
使用扳手检查电动机与减速机联轴器的螺栓,应紧固无松动,检查弹性联轴器胶套、胶圈,如有磨损、老化,应立即更换
C.
运转中需要检查轴承有无异常的滚动声及异常的振动等
D.
根据制造单位维护保养说明书的要求,对曳引轮轴承和导向轮轴承进行润滑,润滑时特别注意润滑油或润滑脂的油质