简介:ToovercomethelimitationoflowimagesignalswingrangeandlongresettimeinfourtransistorCMOSactivepixelimagesensor,achargepumpcircuitispresentedtoimprovethepixelresetperformance.Thechargepumpcircuitconsistsoftwostageswitchcapacitorserialvoltagedoubler.Cross-coupledMOSFETswitchstructurewithwellcloseandopenperformanceisusedinthesecondstageofthechargepump.Thepixelresettransistorwithgatevoltagedrivenbyoutputofthepumpworksinlinearregion,whichcanaccelerateresetprocessandcompleteresetisachieved.Thesimulationresultsshowthatoutputofthechargepumpisenhancedfrom1.2to4.2Vwithvoltageripplelowerthan6mV.Thepixelresettimeisreducedto1.14nsindark.Imagesmearduetonon-completelyresetiseliminatedandtheimagesignalswingrangeisenlarged.ThechargepumpissuccessfullyembeddedinaCMOSimagesensorchipwith0.3×106pixels.
简介:Theadiabaticelectrontransportistheoreticallystudiedinazigzaggraphenenanoribbon(ZGNR)junctionwithtwotime-dependentpumpingelectricfields.BymodelingaZGNRp–njunctionandapplyingtheKeldyshGreen’sfunctionmethod,wefindthatapumpedchargecurrentisflowinginthedeviceatazeroexternalbias,whichmainlycomesfromthephoton-assistedtunnelingprocessandthevalleyselectionruleinaneven-chainZGNRjunction.ThepumpedchargecurrentanditsONandOFFstatescanbeefficientlymodulatedbychangingthesystemparameterssuchasthepumpingfrequency,thepumpingphasedifference,andtheFermilevel.AferromagneticZGNRdeviceisalsostudiedtogenerateapurespincurrentandafullypolarizedspincurrentduetothecombinedspinpumpeffectandthevalleyvalveeffect.Ourfindingmightpavethewaytomanipulatethedegreeoffreedomofelectronsinagraphene-basedelectronicdevice.
简介:AnexperimentalapparatustoinvestigateACMHDpumpwasestablished,whichmainlyconsistsofarotarypermanentmagnetwith4polesanannularchannel,amotor,ashaftandaplatform.Themagnetgeneratesafieldsimilartosinusoidwiththemaximumof0.9TinthechannelwhenitisrotatedupbythemotortosimulateanACmagneticfield.Thismovingmagneticfieldactsontheconductivefluidinthechannel,andproducesanelectromagneticforcetomovethefluidinthesamedirectionasthatofthemagnetrotating.Experimentswerecarriedouttoinvestigatetheperformanceofthepump.Flowvelocityintheannularchannelwasmeasuredfordifferentconductivitiesandrotatingspeedsofthemagnet.Theresultsshowthattheflowrateandpressureincreaseasthemagneticfieldstrength,fluidconductivityandfrequencyofthemagneticfieldincrease.
简介:Anewpiezoelectricpumpcanpumpliquideitherforwardorbackwardandadjusttheflowrate.Thusanobjectcanbedrivenforwardorbackwardatdifferentspeeds.Thedriverofthepump,acircularpiezoelectricplate,ismodelledbyFiniteElementMethod(FEM)inANSYSanditsperformanceissimulatedandanalyzed.Thepumpgivesthebestperformancewhenthedrivingsignalsoftheinletandoutletvalveshaveabiggerdutycycleandtheplatehasahighervoltageapplied.
简介:基于海军司烧方程和Spalart-Allmaras骚乱模型,在有long-mid-short片建筑群impeller的离心的泵的三块维的狂暴的流动地数字地计算、分析。在flowpart的相对速度和压力分布被获得。在复杂impeller的经过的流动由于在涡囊和impeller之间的联合行动是不对称的,这被发现。逆流区域在长片的吸方面的入口,在长片的压力方面和短片的吸方面的插头的中间的部分附近。涡囊喉咙附近的流动被涡囊极大地影响。相对速度大,在涡囊喉咙附近在复杂impeller的插头带回来流动是容易的。静电干扰和全部的压力在impeller从入口一致地升起到插头。在impeller插头,压力周期性地严厉地从压力方面减少到吸方面,然后静态的压力喉咙附近的上升。试验性的结果证明在impeller的背流动在泵的表演上有重要影响。
简介:BackgroundIntra-aorticballoonpump(IABP)hasbeenwidelyusedatpresent.Wecanuseitatdifferentstagesofperioperativeperiodinoff-pumpcoronaryarterybypassgrafting(CABG).However,whentouseditwasseldomconfirmed.MethodsFromJanuary2008toJune2012,the89coronaryheartdisease(CHD)patientsacceptedimplantationofIABPatdifferentstagesofoff-pumpCABG,preoperativeandpostoperativeventricularsystolicfunction,leftventricularremodelingsituationandthechangesofmyocardialenzymeswereevaluated.ResultsAllthepatientshadleftheartinsufficiencyandmultivesseldisease.TheirpostoperativeleftventricularsystolicfunctionandventricularremodelingweresignificantlyimprovedwhilemyocardialenzymesdecreasedwithpreoperativeinterventionalimplantationofIABP.Theperioperativemortalitywas7.86%(7/89).NopatientshadcomplicationofIABP.ConclusionEarlierIABPimplantationatpreoperationisusefultoimproveheartfunction,improvethetolerabilityofsurgery,reducetheincidenceofpostoperativelowcardiacoutputsyndrome(LCOS)anddecreasethemortality.
简介:Thispaperpresentsasemi-empiricallumpedparametermodeldevelopedforanalysingthedynamicstabilityandperformancelimitationsofapressurecompensatedvanepumpforanautomotiveapplicationwithlow-costcomponents.Themodelcalculatescontinuousdisplacementchamberpressureprofilesandinertialeffectsforthedeterminationoftheinternalforcesactingonthevanepump'spivotingcam.Measurementsconductedonacustomteststandwereusedtodefineanonlinearlyprogressivebiasspringmodelandablackboxrepresentationofthepumpcontrolsystemvalves.Analysisofthecompletemodelrevealsthattheperformancelimitationsimposedbythecontrolsystemvalves,intermsofsystemstabilityandachievablecontrollerbandwidth,aremorerestrictivethanthelimitationsimposedbythelow-costvanepumpandlimitthethatbandwidthto1.84Hz.Thecontrolsystemalsoimposeslimitationstothesystemperformancebasedonresonancephenomenawhichmaybesignificantinsomeapplications.
简介:PartandDraftmodulesofSolidEdgeareusedtoconstruct3Dsolidmodelsandgeneratepartdrawings,whileActiveXAutomationofVBisusedtoaccessengineeringdatabasefilestorealizedimension-drivenmodificationofthedesignedparts.Moreover,VBplaystheenablingroleofintegratingallworkprocessesofgearpumpdesign,resultinginacomprehensiveCADsystem.
简介:Thispaperpresentsasemi-empiricallumpedparametermodeldevelopedforanalysingthedynamicstabilityandperformancelimitationsofapressurecompensatedvanepumpforanautomotiveapplicationwithlow-costcomponents.Themodelcalculatescontinuousdisplacementchamberpressureprofilesandinertialeffectsforthedeterminationoftheinternalforcesactingonthevanepump'spivotingcam.Measurementsconductedonacustomteststandwereusedtodefineanonlinearlyprogressivebiasspringmodelandablackboxrepresentationofthepumpcontrolsystemvalves.Analysisofthecompletemodelrevealsthattheperformancelimitationsimposedbythecontrolsystemvalves,intermsofsystemstabilityandachievablecontrollerbandwidth,aremorerestrictivethanthelimitationsimposedbythelow-costvanepumpandlimitthethatbandwidthto1.84Hz.Thecontrolsystemalsoimposeslimitationstothesystemperformancebasedonresonancephenomenawhichmaybesignificantinsomeapplications.
简介:AstablewavelengthoperationHo:YAGlaserdual-pumpedbytwoorthogonallypolarizedTm:YLFlasersisreported.Underthecwoperationmode,alaseroutputpowerof24Wismeasured.Thecorrespondingopticalopticalconversionefficiencyis44.75%andtheslopeefficiencyis50.12%.UndertheQ-switchedoperationmode,theoutputmaximumaveragepoweris22.8Watthere-frequencyof6kHz.Thecorrespondingoptical-opticalconversionefficiencyandslopeefficiencyare42.64%and48.01%,respectively.Theoutputcentralwavelengthis2090.73nm,thelinewidthis0.40nm,andthebeamqualityisM~2<1.6.Moreover,theshiftoftheoutputcentralwavelengthislessthan0.01nm,andthelinewidthshiftisalsolessthan0.01nm.
简介:AIMToinvestigatetheinfluenceofprotonpumpinhibitors(PPIs)exposureonthediagnosisofHelicobacterpylori(H.pylori)gastritisandintestinalmetaplasia.METHODS:ChronicPPIuseisassociatedwithmaskingofH.pyloriinfection.PatientswithH.pyloriinfectionarepredisposedtogastricandduodenalulcers,andlong-terminfectionwiththisorganismhasbeenassociatedwithgastricmucosalatrophyandseriouslong-termcomplications,suchasgastriclymphomaandadenocarcinoma.ThreehundredpatientsdiagnosedwithgastritisbetweenJanuary2008andApril2010wereincludedinourstudy.Thecomputerizedmedicaldatabaseofthesepatientswasreviewedretrospectivelyinordertoassesswhetherthetypeofgastritisdiagnosed(H.pylorivsnon-H.pylorigastritis)isinfluencedbyPPIexposure.H.pyloridensitywasgradedaslow,ifcorrespondingtomilddensityfollowingtheUpdatedSydneySystem,orhigh,ifcorrespondingtomoderateorseveredensitiesintheUpdatedSydneySystem.RESULTS:Patientswereequallydistributedbetweenmalesandfemaleswithamedianageatthetimeofdiagnosisof50yearsold(range:20-87).ThehistologicaltypesofgastritiswereclassifiedasH.pylorigastritis(n=156,52%)andnon-H.pylorigastritis(n=144,48%).Allpatientswithnon-H.pylorigastritishadinactivechronicgastritis.PatientswithnopreviousPPIexposureweremorelikelytobediagnosedwithH.pylorigastritisthanthosewithpreviousPPIexposure(71%vs34.2%,P〈0.001).Intestinalmetaplasiawasmorelikelytobedetectedinthelatterpatients(1.4%vs6.5%,P=0.023).MultivariateanalysishasalsodemonstratedthatinthepresenceofpreviousPPIexposure(OR=0.217,95%CI:0.123-0.385),GERD(OR=0.317,95%CI:0.132-0.763,P=0.01),alcoholintake(OR=0.396,95%CI:0.195-0.804,P=0.01),thedetectionofH.pyloriwaslesslikely.ChronicuseofPPIsmaymaskH.pyloriinfectionspromotingthediagnosisofnon-H.pylorigastritisandleadstoasi
简介:Understandingtheradiationmodelofaflashlampisessentialforthereflectordesignofalaseramplifier.Reflectordesignofteninvolvesseveralsimplifyingassumptions,likeapointorLambertiansource;eitheroftheseassumptionsmayleadtosignificanterrorsintheoutputdistribution.Inpractice,sourcenon-idealitiesusuallyresultinsacrificingtheamplifier’sgaincoefficient.Weproposeanoveltesttechniqueforattainingthexenonflashlampabsolutespectralintensityatvariousanglesofview,andthenaccuratelypredictradiationdistributionsandgeneratethereflectorshape.Itisshownthatduetotheabsorptionofemittedradiationbythelampitself,thebehavioroftheradiationmodelatvariouswavelengthsisdifferent.Numericalresultsofxenonplasmaabsorptioncoefficientwerecomparedwiththemeasureddata.Areasonableagreementwasobtainedfortheabsorptioncoefficientparameters.Thus,thisworkprovidesausefulanalyticaltoolfortheengineeringdesignoflaseramplifierreflectorsusingxenonflashlampsaspumps.
简介:WITElectronicFuelSystemCo.,Ltd.hasdevelopedanewfuelinjector,theElectronicIn-linePump(EIP)system,designedtomeetChina’sdieselengineemissionandfueleconomyregulations.ItcanbeusedonmarinedieselenginesandcommercialvehicleenginesthroughdifferentEIPsystems.AnumericalmodeloftheEIPsystemwasbuiltintheAMESimenvironmentforthepurposeofcreatingadesigntoolforengineapplicationandsystemoptimization.Themodelwasusedtopredictkeyinjectioncharacteristicsunderdifferentoperatingconditions,suchasinjectionpressure,injectionrate,andinjectionduration.Tovalidatethesepredictions,experimentaltestswereconductedundertheconditionsthatweremodeled.Theresultswerequiteencouragingandinagreementwithmodelpredictions.AdditionalexperimentswereconductedtostudytheinjectioncharacteristicsoftheEIPsystem.Theseresultsshowthatinjectionpressureandinjectionquantityareinsensitivetoinjectiontimingvariations,thisisduetothedesignoftheconstantvelocitycamprofile.Finally,injectionquantityandpressurevs.pulsewidthatdifferentcamspeedsarepresented,animportantinjectioncharacteristicforEIPsystemcalibration.
简介:Sinceitsintroductionin1967,intra-aorticballoonpumping(IABP)hasbecomethemainstayinthemanagementofacuteleftventriculardysfunctioninthecriticalcaresetting.Typically,presentIABPsystemsareunabletoprovideconsistent,effectivecar-diacassistanceinthepresenceofarrhythmiasorrapidlychangingheartrates.Anew-generation,closedloop,fullyautomaticintra-aorticballoonpump(CL-IABP)