简介:摘要本文分别对MARC和DC的发展和特点进行了详细的阐述,并比较分析了其不同点。在此基础上说明了当今社会MARC、DC并存的的意义
简介:Thegasdynamicandelectromagneticfactorsaffectingthepositionofarcrootsinatubulararcheaterareanalyzed.Magnitudesofthevariousfactorsareestimatedthroughnumericalmodelling,andtheoverallactiononthearcassessed.Itisfoundthattheactionsonthearcintherearelectrodecanbebalancedinastablemannerandthearcrootcanbestabilizedatacertainaxialposition.Inthefrontelectrode,thevariousfactorscannotbebalanced,andthearerootcanonlystaywithintheelectrodethroughthemechanismofrecurrentshunting.Theseconclusionsagreewithexperimentalobservations.
简介:煤气的金属弧焊(GMAW)的数字模型正在试着联合液体(VoF)的弧和体积的magnetohydrodynamics(MHD)模型的电流金属转移当模特儿。他们忽视蒸发并且为弧区域假定氩气氛,因为它是为煤气的钨弧焊的模型的普通实践。这些模型在20000K和类似于钨的温度分布上面预言温度惰性的气体(TIG)弧。然而,在GMAW弧的当前的分光镜的温度大小表明低得多的弧温度。与TIG弧相对照,他们发现了光线的温度分发的中央本地最小。纸论述考虑金属蒸汽的一个GMAW弧模型并且它在与试验性地观察的温度的一个很好的协议。而且,模型能第一次在光线的温度和光线的电流密度分布预言本地中央最小。向轴的方向焊接火炬,工作片,电线和弧(液体领域)的对称的模型象在氩的狂暴的混合和金属蒸汽的热demixing一样实现MHD。从模拟获得的铁蒸汽的集体部分在2000~5000K在弧的穗上在弧核心和另一累积显示出累积。demixing效果导致在这二个区域之间的铁的很低的集中。敏感分析证明运输的影响和金属蒸汽的放射性质喂。最后模型预言与Zieliska等的测量结果相比。
简介:Thearcsprayingprocessisdividedintotwostages:thefirststageisatomization-sprayingstream(ASS)andthesecondoneissprayingdeposition(SD).Thenstudystatusisdescribedofbothstages'physicalmodelandcorrespondingcontrolling-equation.Basedontheanalysisofstudystatus,theconclusionasfollowsisgot.TheheatandmasstransfermodelswithtwoorthreedimensionsinASSstageshouldbeestablishedtofardeeplyanalysesthedynamicalandthermalbehavioroftheoverheatdroplet.Thestatisticslawofoverheateddropletsshouldbefurtherstudiedbyconnectingsimulationwithexperiments.MorepropervalidationexperimentsshouldbedesignedforflatteningsimulationtomodifythemodelsinSDstage.
简介:AprototypeofPulsedPlasmaArcCladdingsystemwasdeveloped,inwhichsinglepowersourcesuppliesbothtransferredplasmaarc(TPA)andnon-transferredplasmaarc(N-TPA).BothplasmasworkinturninahighfrequencycontrolledbyanIGBTconnectingnozzleandworkpiece.TheworkingfrequencyofIGBTrangesfrom50~7000Hz,inwhichtheplasmascanworkinturnsmoothly.Higherthan500HzofworkingfrequencyissuggestedforpromotionofcladdingqualityandprotectionofIGBT.DragphenomenonofTPAintensifiesasthefrequencygoesup,whichtendstoincreasethecurrentproportionofTPAandsuppressN-TPA.TheoccupationratioofIGBTcanberegulatedfrom5%~95%,whichbalancesthepowersuppliesofbothplasmas.Anoccupationratiohigherthan50%givesadequateproportionofarccurrentforN-TPAtopreheatpowder.
简介:Forgivendata(ti,yi),I=0,1,…,n,0=t0<t1<…<tn=1westudyconstrainedinterpolationproblemofFavardtypeinf{‖f'‖∞|f∈W2∞[0,1],f(ti)=yi,i=0,…,n,l(f;[0,1])≤l0},wherel(f';[0,1])=∫10/1+f'2(x)dxisthearclengthoffin[0,1].Weprovetheexistenceofasolutionf*oftheaboveproblem,thatisaquadraticsplinewithasecondderivativef'*,whichcoincideswithoneoftheconstants-‖f'*‖∞,0,‖f'*‖∞betweeneverytwoconsecutiveknots.Thus,weextendaresultofKarlinconcerningFavardproblem,tothecaseofrestrictedlengthinterpolation.
简介:Thispaperpresentsanewsplinecalledarcspline.Ittakestwoarcsconnectingadjacentpointsamongasampledseries,withknowntangentalofeachsampledpoint.Thecalculationfortheparallel.thecurvelengthandthesegment-ingpointcoordinatesaresimple,thusmakingmapsymbolgenerationsimplified.When'arclet'occurs,somespecialprocessingmustbetaken.
简介:Aspectraldiagnosticsofcomplexareplasmausingmultiplespectralinformationofareself-emittingispro-posed.Thismethodisabletosimultaneouslydeterminecomponentdensities,thecorrespondingtemperatureandtheirdis-tributionsbyafewlineintensitiesmeasurent.Theprincipleofthemethodandtherelevantmeasuringsystemarede-scribed.Anequationsystemisestablishedforcomputationofthestatevariablesinareplasma.Anexperimentunderweldingareconditionismadeasanapplicationofthemethod.Theeffectsofprobableerrorsourcesonthemeasurementarealsoanalysed.
简介:ONARC┐TRANSITIVECIRCULANTDIGRAPHSHUANGQIONGXIANGAbstract.DenotebyCn(S)thecirculantdigraphwithvertexsetZn={0,1,2,...,n-1}andsy...
简介:Thevariationinarccharacteristicsandbehaviorofmetaltransferwiththechangeinpulseparametershasbeenstudiedbyhighspeedvideocameraduringpulsecurrentflux-coredarcwelddeposition.Acomparativestudyofsimilarnaturehasalsobeencarriedoutduringflux-coredarcwelddepositioninglobularandspraytransfermodes.Theeffectofpulseparametershasbeenstudiedbyconsideringtheirmeancurrentandarcvoltage.Thearccharacteristicsstudiedbyitsrootdiameter,projecteddiameterandlength,andthebehaviorofmetaltransfernotedbythemetaltransfermodelandthedropletdiameterhavebeenfoundtovarysignificantlywiththepulseparameters.TheobservationmayhelpinunderstandingthearccharacteristicswithrespecttothevariationinpulseparameterswhichmaybebeneficialinusingpulsecurrentFCAWtoproducedesiredweldquality.
简介:Manyapplicationsofultrasonic-assistedmethodswereusedduringmetalsolidification,buttheycouldnotbeintroducedintoweldpool.Inthispaper,awayofultrasonicassistedTIGweldingisintroduced.Bydirectlyimposedultrasonicvibrationonweldingarc,thevibrationinteractswitharcplasmaandpassestotheweldpool.Measurementresultsshowthatarcpressureissignificantlyincreasedwiththeultrasonicvibrationandthearcpressuredistributionmodelsarechanged.Bead-on-plateweldingtestsonSUS304confirmthatthistechnologycaninfluencethestyleofmetalmeltingandincreaseweldpenetrationdepth.
简介:<正>CENTRALCHINAARCSERIESANDITSMETALLOGENYJiangZhenya(HubeiInstituteofGeoscience,Wuhan,430022,Hubei,P.R.China)arc,metailogeny,CentralChinaThecentralChinaarcseriesliesacrossthewholecentralChina,embodyingQinghuaiarc,Esuarc,Changjiangarc,Chuzhearc,andXianggangarc.Itisagigantictecton-icarcseries.TheseriesistheresultofnorthandsouththrustingofhorizontaldiferrentialbucklingundertheuniversalnorthandsouthcompressingineasternChina.ItbeganatYingzhimovement,formedatthefirststageofYanshanmovement,andsolidifiedatthesceondstageofYanshanmovement.Theseriescontrollssedimentation,exogenicdeposits,magmatism,andendogenicdeposits.Menawhileitaffectsmordentopography,alluvialsystem,andclimate.
简介:AnexperimentalsystemofACarcdischargeinwaterwasdesignedwithpole-poleelectrodesandapeakvoltageof1500Vandatestcircuitwassetupusingvirtualinstrumenttechnology.ThemechanismofanACplasmaarcgeneratedinwaterwasanalyzed.ThevoltagecurrentcharacteristicoftheACplasmaarcwasobtainedfromthewaveform.Thetemperaturecharacteristicwastestedwithaspectrumdiagnosissystem,andtheeffectofdifferentelectrodematerialsonthestrikingvoltageandpeakcurrentwasanalyzed.Theresultsshowthatwhenapowersupplyof6kWisappliedonelectrodeswithagapof2mminwater,thestrikingvoltageisfrom900Vto1300V,thearcvoltageisfrom40Vto100V,thearccurrentisfrom2Ato7A,andthezerorestperiodisfrom1msto2ms.Inaddition,thearcvoltageandcurrentaredifferentforelectrodesinaluminum,copperandstainlesssteel.Thearcvoltageislowerandthecurrentishigherforanaluminumelectrodethanthoseforcopperandstainlesssteelones.Thehighesttemperatureofthearcis7643K.
简介:Thekeyproblemfornumericalsimulationofplasmaarcwelding(PAW)processistodevelopasuitableandadaptivevolumetricheatsourcemodewhichreflectsthephysicalcharacteristicsofkeyholePAW.Tothisend,thekeyholegeometryunderdifferentPAWprocessconditionsmustbepredicted.Inthispaper,amathematicalmodelfordeterminingthekeyholeshapeisdevelopedwithconsideringthemassandmomentumconservationofthein-keyholeplasmajetaswellasthepressureequilibriumattheplasmajet/liquidmetalboundary.AsuitableheatsourcemodelrelatedtothekeyholeshapeisappliedtothecalculationofPAWwelddimensions.Thepredictedresultsareingoodagreementwiththeexperimentalones.
简介:Throughtheinvestigationontraditionalarcstudweldingprocess,anewweldinggunanditscontrolsystemweredevelopedinthispaper.Thesteppingarcstudweldinggunwasmainlymadebyasteppingmotorasactuatingunitandascrew-drivendeviceasmovingunit.AcontrolsystemwithaMCS-51single-chipmicrocomputerasmaincontrolcomponentwasusedtorealizethenewstudweldingprocedure.Thisnewweldingprocesswithsteppingstudweldinggunisnamedassteppingarcstudwelding.Inthenewweldingprocess,thestudactioncanbelookedasconstitutedbysomemicrosteps.Thesettingandadjustingofthesteppingarcweldinggunbehaviorparametersareaccomplishedindependently.Itisindicatedfromtheresultsofprocesstestsandbendingtestthatthesteppingarcstudweldingprocessispracticable.