测量螺旋桨螺距时采用的量具是()。 ["螺距规","直尺","塞尺","桥规"]
ZPW-2000系列制式环线发码设备调制低频周期误差小于()。 ["A、+0.05HZ","B、+1HZ","C、+2HZ","D、+3HZ"]
检查YJ19卷烟机上胶器所有零件的磨损和受损的情况时,特别注意检查‘O’型环、隔膜和调节器的()。 ["螺纹线","针阀","磨损情况","阻尼"]
YJ19卷烟机在()生产结束后,应对上胶器喷嘴及周围区域进行清洁。 ["每周","每班","每天","每两周"]
直径为1.25cm,频率为2.25MHz的换能器在水中的半扩散角为()。 ["17.4°","27°","40.5°","61°"]
沅水流域6-8月洪水各有什么特点?