【单选题】He hasn't slept at all for three days. ____he is tired out. [ ]
【单选题】下列哪一种敏感元件不属于弹性式压力敏感元件()
【单选题】He hasn't slept at all for three days. _____ he is tired out. [ ]
【简答题】There is a big in our city. We can see many there. A(n) , the biggest animal on land is also there. Many birds fly in the sky(在天空飞).Some beautiful ducks (鸭子)always in the river. What are these i...
【单选题】光栅位移传感器,是利用光栅的( )来工作的测量反馈装置。
【多选题】实施保护接零的三‘目四线,“供电系“中采取重复接地的作用是()
A.
将变压器零线已相四线制供电系统中的零千线〕多点接地〔重复接地〕,目的是防止变压器零线断线造成该线路上电气设备金属外亮带电的严重后果
C.
采用重复接地后,如果变压器零线断线,接零设备发生漏电或接零设备带电部分碰外亮时仍有安全保护,而且不会发生其他完好接零设备外亮带触电电压,对保护人身安全有很重要的作用
【单选题】变换力的弹性元件有很多种,下列哪种弹性元件不属于变换力弹性元件
【判断题】接地的主要作用是保证人身和设备的安全,若按接地的目的及工作原理来分工作接地、保护接地、保护接零和重复接地
【单选题】It is a fact that there is a (n) _______ towards regional cooperation.