共查询到3条相似文献,搜索用时 15 毫秒
1.
Inmodernuninterruptablepowersupplies ,in verterswith pulsewidthmodulation (PWM )con trolareusedtogeneratethesinusoidaloutputvolt age .Therequirementstoinvertersincludeahighstability ,highreliability ,fastdynamicresponseoveralltypesofloads,aswellasminimumtotalharmonicdistortion .Inthepast,openloopcontrolwithfeed for wardwereusedininverterstoproducethesinusoi dalwaveoutput ,whilearelativelyslowoutputvoltagermsfeedbackloopwereusedtoregulatethermsoftheoutputvoltage .Althoughthistypeofcontrolcould… 相似文献
2.
Theclassiccableequationhasbeenusedtore presenttheexcitationoflongandstraightperipheral nervesinanelectricfield.Itpredictsthatexcitation occursnearthemaximumofthenegativefirstspa tialgradient-E'‖=- Ex/ xinthedirectionofan x axialfiber[1],whichisinagreem… 相似文献
3.
刘俊田 《西安交通大学学报(英文版)》1998,(2)
Occlusivevasculardisorders,bothvenousandarterial,aresomeofthemostcommoncausesofmorbidityandmortalityindevelopedcountries.Theaimoftherapyinsuchconditionsis,firstly,torestoreandmaintainbloodflowtotheaffectedtissueororgan,andsecondly,torestorethesystemtothenormalhaemostaticstatewithoutovercompensatingandproducingcomplicationssuchashaemorrhage.Thrombolyticagents,suchasrecombinanttissueplasminogenactivator(rt-PA),arewidelyusedinthetreatmentofpatientswithacutemyocardialinfarction.However,successful… 相似文献