作业时禁止向滑轮上套钢丝绳,禁止在卷筒、滑轮附近用手触碰运行中的钢丝绳,禁止跨越行走中的钢丝绳,禁止在导向滑轮的内侧()。
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未动操作的情况下轴流式调压阀阀后压力升高并与上游压力持平的原因可能是()。
A. 鼠笼上有赃物
B. 节流针阀被赃物堵塞
C. 用户减少用气量
D. A和C
设有接触网的线路上,特殊情况下可以攀登车顶及在车辆装载的货物之上作业。()
A. 正确
B. 错误
Many diesel engine exhaust valves are being constructed with hollow stems filled with sodium in order to ()
A. provide added wear protection against today’s corrosive quality of fuel
B. increase overall valve strength due to the high gas pressures
C. assist in dissipating heat due to the extreme operating temperatures
D. reduce the overall weight of the valve thus helping eliminate valve spring surge and hammering
男性,40岁,发作性咳嗽、气喘4年,近日外出旅游后咳嗽加剧。最可能的疾病是()
A. 支气管肺癌
B. 急性左心衰
C. 支气管哮喘
D. 慢性支气管炎
E. 支气管结核