学科分类
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54 个结果
  • 简介:在垂直的泵的吸入附近的流动结构试验性地并且数字地被调查以便在设计垂直的泵,没有失去高效,他们的安装区域在被要求最小的吸入的最佳形状获得一个指南。我们作为泵的形状的一个代表性的特征在吸入的扩大比率上集中我们的注意并且在泵性能上调查扩大比率的效果。如果我们为泵的安装需要的区域应该是最小的考虑,最佳扩大比率在1.1锝?.2变化,这被结束如果我们为泵的安装需要的区域应该是最小的考虑。关键词垂直的泵-吸入的形状-在吸入CLC数字TK7附近的流动结构

  • 标签: 立式泵 通风口外形 进口流动结构 导向索
  • 简介:ToovercomethelimitationoflowimagesignalswingrangeandlongresettimeinfourtransistorCMOSactivepixelimagesensor,achargepumpcircuitispresentedtoimprovethepixelresetperformance.Thechargepumpcircuitconsistsoftwostageswitchcapacitorserialvoltagedoubler.Cross-coupledMOSFETswitchstructurewithwellcloseandopenperformanceisusedinthesecondstageofthechargepump.Thepixelresettransistorwithgatevoltagedrivenbyoutputofthepumpworksinlinearregion,whichcanaccelerateresetprocessandcompleteresetisachieved.Thesimulationresultsshowthatoutputofthechargepumpisenhancedfrom1.2to4.2Vwithvoltageripplelowerthan6mV.Thepixelresettimeisreducedto1.14nsindark.Imagesmearduetonon-completelyresetiseliminatedandtheimagesignalswingrangeisenlarged.ThechargepumpissuccessfullyembeddedinaCMOSimagesensorchipwith0.3×106pixels.

  • 标签: 电荷泵电路 CMOS 像素 复位 有源 驾驶
  • 简介:Theadiabaticelectrontransportistheoreticallystudiedinazigzaggraphenenanoribbon(ZGNR)junctionwithtwotime-dependentpumpingelectricfields.BymodelingaZGNRp–njunctionandapplyingtheKeldyshGreen’sfunctionmethod,wefindthatapumpedchargecurrentisflowinginthedeviceatazeroexternalbias,whichmainlycomesfromthephoton-assistedtunnelingprocessandthevalleyselectionruleinaneven-chainZGNRjunction.ThepumpedchargecurrentanditsONandOFFstatescanbeefficientlymodulatedbychangingthesystemparameterssuchasthepumpingfrequency,thepumpingphasedifference,andtheFermilevel.AferromagneticZGNRdeviceisalsostudiedtogenerateapurespincurrentandafullypolarizedspincurrentduetothecombinedspinpumpeffectandthevalleyvalveeffect.Ourfindingmightpavethewaytomanipulatethedegreeoffreedomofelectronsinagraphene-basedelectronicdevice.

  • 标签: 纳米带 锯齿型 石墨 泵效 量子 绝热
  • 简介:纸在操作条件的部分流动指光线的流动泵更弥漫的翼更少的行为。一些试验性的数据用2D/2CPIV和在内的不稳定的压力大小被获得了更弥漫,处于各种各样的操作条件。以更低的流动率的试验性的结果与二维的数字计算相比。

  • 标签: 旋转式喷灌器 喷头 不稳定性 方法
  • 简介:AnexperimentalapparatustoinvestigateACMHDpumpwasestablished,whichmainlyconsistsofarotarypermanentmagnetwith4polesanannularchannel,amotor,ashaftandaplatform.Themagnetgeneratesafieldsimilartosinusoidwiththemaximumof0.9TinthechannelwhenitisrotatedupbythemotortosimulateanACmagneticfield.Thismovingmagneticfieldactsontheconductivefluidinthechannel,andproducesanelectromagneticforcetomovethefluidinthesamedirectionasthatofthemagnetrotating.Experimentswerecarriedouttoinvestigatetheperformanceofthepump.Flowvelocityintheannularchannelwasmeasuredfordifferentconductivitiesandrotatingspeedsofthemagnet.Theresultsshowthattheflowrateandpressureincreaseasthemagneticfieldstrength,fluidconductivityandfrequencyofthemagneticfieldincrease.

  • 标签: 流体动力学 水泵 实验研究 施工工程
  • 简介:Anewpiezoelectricpumpcanpumpliquideitherforwardorbackwardandadjusttheflowrate.Thusanobjectcanbedrivenforwardorbackwardatdifferentspeeds.Thedriverofthepump,acircularpiezoelectricplate,ismodelledbyFiniteElementMethod(FEM)inANSYSanditsperformanceissimulatedandanalyzed.Thepumpgivesthebestperformancewhenthedrivingsignalsoftheinletandoutletvalveshaveabiggerdutycycleandtheplatehasahighervoltageapplied.

  • 标签: 仿生水下推进装置 压电泵 控制阀 磁性线圈
  • 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。

  • 标签: 复合叶轮 离心泵 数值模拟 STOKES方程 压力分布 流量
  • 简介:热泵周期广泛地为他们的高效率被用于干衣机。然而,自从一个标准热泵周期不能在低温度操作,电的加热器经常是的lowefficiency在早为冻结的食物或冬季弄干舞台期间使用了。这研究介绍了代替电的加热器在低温度改进干衣机性能的串联热泵。实验被执行在与周围的温度,低阶段的周期团流动率,和高阶段的周期团流动的关系在串联热泵干衣机的性能检验变化率。结果与串联热泵周期的介绍在低温度的干衣机性能显示出重要改进。

  • 标签: 低温干燥机 热泵循环 热泵干燥装置 R134A R404A 电加热器
  • 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.

  • 标签: 围手术期 冠状动脉 体外循环 主动脉 球囊 患者
  • 简介:Thispaperpresentsasemi-empiricallumpedparametermodeldevelopedforanalysingthedynamicstabilityandperformancelimitationsofapressurecompensatedvanepumpforanautomotiveapplicationwithlow-costcomponents.Themodelcalculatescontinuousdisplacementchamberpressureprofilesandinertialeffectsforthedeterminationoftheinternalforcesactingonthevanepump'spivotingcam.Measurementsconductedonacustomteststandwereusedtodefineanonlinearlyprogressivebiasspringmodelandablackboxrepresentationofthepumpcontrolsystemvalves.Analysisofthecompletemodelrevealsthattheperformancelimitationsimposedbythecontrolsystemvalves,intermsofsystemstabilityandachievablecontrollerbandwidth,aremorerestrictivethanthelimitationsimposedbythelow-costvanepumpandlimitthethatbandwidthto1.84Hz.Thecontrolsystemalsoimposeslimitationstothesystemperformancebasedonresonancephenomenawhichmaybesignificantinsomeapplications.

  • 标签:
  • 简介:PartandDraftmodulesofSolidEdgeareusedtoconstruct3Dsolidmodelsandgeneratepartdrawings,whileActiveXAutomationofVBisusedtoaccessengineeringdatabasefilestorealizedimension-drivenmodificationofthedesignedparts.Moreover,VBplaystheenablingroleofintegratingallworkprocessesofgearpumpdesign,resultinginacomprehensiveCADsystem.

  • 标签: CAD 齿轮泵 VB 立体侧面
  • 简介:Thispaperpresentsasemi-empiricallumpedparametermodeldevelopedforanalysingthedynamicstabilityandperformancelimitationsofapressurecompensatedvanepumpforanautomotiveapplicationwithlow-costcomponents.Themodelcalculatescontinuousdisplacementchamberpressureprofilesandinertialeffectsforthedeterminationoftheinternalforcesactingonthevanepump'spivotingcam.Measurementsconductedonacustomteststandwereusedtodefineanonlinearlyprogressivebiasspringmodelandablackboxrepresentationofthepumpcontrolsystemvalves.Analysisofthecompletemodelrevealsthattheperformancelimitationsimposedbythecontrolsystemvalves,intermsofsystemstabilityandachievablecontrollerbandwidth,aremorerestrictivethanthelimitationsimposedbythelow-costvanepumpandlimitthethatbandwidthto1.84Hz.Thecontrolsystemalsoimposeslimitationstothesystemperformancebasedonresonancephenomenawhichmaybesignificantinsomeapplications.

  • 标签: PRESENTS SEMI-EMPIRICAL lumped PARAMETER CHAMBER
  • 简介:影响在噪音特征上由拉曼效果导致了一弄空并且有损耗的双泵纤维光参量的放大器(FOPA)被调查。考虑拉曼效果,修改联合振幅方程第一被造,然后,拉曼的影响在Stokes和反上完成--司烧有不同起始的信号力量的波长进一步被分析。而且,FOPA获得上的效果也与一样的起始的信号力量和经常的噪音数字(NF)被显示出。

  • 标签: 拉曼效应 噪声特性 双泵 光参量放大器 信号功率 反斯托克斯
  • 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.

  • 标签: YAG length Ho A STABLE WAVELENGTH
  • 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

  • 标签: GASTRITIS Diagnosis HELICOBACTER PYLORI PROTON pump
  • 简介:Understandingtheradiationmodelofaflashlampisessentialforthereflectordesignofalaseramplifier.Reflectordesignofteninvolvesseveralsimplifyingassumptions,likeapointorLambertiansource;eitheroftheseassumptionsmayleadtosignificanterrorsintheoutputdistribution.Inpractice,sourcenon-idealitiesusuallyresultinsacrificingtheamplifier’sgaincoefficient.Weproposeanoveltesttechniqueforattainingthexenonflashlampabsolutespectralintensityatvariousanglesofview,andthenaccuratelypredictradiationdistributionsandgeneratethereflectorshape.Itisshownthatduetotheabsorptionofemittedradiationbythelampitself,thebehavioroftheradiationmodelatvariouswavelengthsisdifferent.Numericalresultsofxenonplasmaabsorptioncoefficientwerecomparedwiththemeasureddata.Areasonableagreementwasobtainedfortheabsorptioncoefficientparameters.Thus,thisworkprovidesausefulanalyticaltoolfortheengineeringdesignoflaseramplifierreflectorsusingxenonflashlampsaspumps.

  • 标签: ABSORPTION COEFFICIENT current density RADIATION model
  • 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.

  • 标签: EIP 海洋工程 燃料注入系统 动力装置
  • 简介:木材干燥能耗高的原因之一是常规蒸汽干燥的排气热损失大,能量利用率低.除湿干燥与太阳能干燥都是节能效果好的干燥方法,该文介绍了作者在这方面的研究成果,阐述了除湿机与太阳能联合干燥系统的设备组成与工作原理、技术特点与试验测试数据,最后对此类干燥技术作了一些评价和建议.

  • 标签: 木材干燥 除湿机 太阳能
  • 简介:Sinceitsintroductionin1967,intra-aorticballoonpumping(IABP)hasbecomethemainstayinthemanagementofacuteleftventriculardysfunctioninthecriticalcaresetting.Typically,presentIABPsystemsareunabletoprovideconsistent,effectivecar-diacassistanceinthepresenceofarrhythmiasorrapidlychangingheartrates.Anew-generation,closedloop,fullyautomaticintra-aorticballoonpump(CL-IABP)

  • 标签: balloon PUMPING unable ASSISTANCE PUMPED augmentation