离心泵振动并发出较大噪声,是由于()引起的。A.联轴器不同心 B.泵的运转温度过低 发布时间:2017-05-26 03:28 │ 来源:www.tikuol.com 题型:单项选择题 问题: 离心泵振动并发出较大噪声,是由于()引起的。A.联轴器不同心B.泵的运转温度过低C.电机电流不足D.吸人管路堵塞
题型:单项选择题 用所给词的适当形式填空。1. My sister is a_____ girl. She does everything _____ (care) .2. There are a few _____ (ladder)under the apple trees.3. Danny was _____ (injure) yesterday.4. I heard him _____ (go) out just now.5. Look! Danny _____ (lie) on the floor. 查看答案
题型:单项选择题 已知限流孔板前后压力P1=1.96×106Pa,P2=1.47×106Pa,压缩系数Z1=1,孔板直径do=10mm,限流孔系数C=0.7。相对分子质量M=18,气体绝热指数K=1.4,温度t=30℃,则气体流量W是()。A.895.33kg/hB.626.73kg/hC.470.05kg/hD.335.00kg/h 查看答案