题目内容

测流体流量时，随流量增加孔板流量计两侧压差值将增加，若改用转子流量计，随流量增加转子两侧压差值将不变

查看答案

搜索结果不匹配？点我反馈

更多问题

静止液体内部压力与其表面压力无关。

Yourdatabasehasexperiencedalossofdatafileusers_01.dbf，whichisassociatedwithaablespacecalledUSERS.
Thedatabaseisstillrunning.
Whichanswerproperlydescribestherderofthestepsthatyouwouldusetorecoverfromthiserror？（）
a. Shutdownthedatabase.
b.Taketheusers_01.dbfdatafileofflinewiththealterdatabasecommand.
c.Restoretheusers_01.dbfdatafilefrombackupmediawiththerequiredarchivedredologs.
d.Restorealluserstablespace-relateddatafilesfrombackupmedia.
e.Issuetherecovertablespaceuserscommand.
f.Issuetherecoverdatafileusers_01.dbfcommand.
g.Startupthedatabase.
h.Bringtheusers_01.dbfdatafileonlinewiththealterdatabasecommand.

离心泵的泵壳既是汇集叶轮抛出液体的部件，又是流体机械能的转换装置。

离心泵的扬程是液体出泵和进泵的压强差换算成的液柱高度。