01入门级别的主语名词/名词短语1)Youngpeopleshouldbeencouragedtobroadentheirhorizons.2)Youngadultsmayendupneverreturningtotheirstudies.3)Thiscarisveryexpensive.4)Thecomputerisagreatinvention.02代词作主语Thesearemypresents.Itiswinternow.03动名词作主语1)Seeingisbelieving.眼见为实。2)Smokingisharmfultopeople’shealth.3)Workingathomeallowspeopletosavemoney.04Todo形式(又称不定式)ToliveinGuangzhouisv...
一、离心泵轴功率计算公式流量×扬程×9.81×介质比重÷3600÷泵效率流量单位:立方/小时,扬程单位:米P=2.73HQ/η,其中H为扬程,单位m,Q为流量,单位为m3/h,η为泵的效率.P为轴功率,单位KW.也就是泵的轴功率P=ρgQH/1000η(kw),其中的ρ=1000Kg/m3,g=9.8比重的单位为Kg/m3,流量的单位为m3/h,扬程的单位为m,1Kg=9.8牛顿则P=比重流量扬程9.8牛顿/Kg=Kg/m3m3/hm9.8牛顿/Kg=9.8牛顿m/3600秒=牛顿m/367秒=瓦/367上面推导是单位的由来...