简介：Thekeyproblemfornumericalsimulationofplasmaarcwelding(PAW)processistodevelopasuitableandadaptivevolumetricheatsourcemodewhichreflectsthephysicalcharacteristicsofkeyholePAW.Tothisend,thekeyholegeometryunderdifferentPAWprocessconditionsmustbepredicted.Inthispaper,amathematicalmodelfordeterminingthekeyholeshapeisdevelopedwithconsideringthemassandmomentumconservationofthein-keyholeplasmajetaswellasthepressureequilibriumattheplasmajet/liquidmetalboundary.AsuitableheatsourcemodelrelatedtothekeyholeshapeisappliedtothecalculationofPAWwelddimensions.Thepredictedresultsareingoodagreementwiththeexperimentalones.

简介：AnanalysistechniquecombiningRBSwithPIXEtechnologybyx-particlesincidentbeamwasconstructedandappliedtoanalyselightimpuritiesinheaviersubstrates.ItcanruninmeasuringRutherfordbackscatteringandX-rayspectrainrandomandchannelingmode,simultaneously.Beingusedtoanalysesulphuratomsim-plantedintoGaAssinglecrystals,thismethodisrelativelysimpleandquick-operating.Itisespeciallyusefulforanalysinglightimpuritiesinsemiconductorcompounds,optoelectronicandmicrowavematerials.

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简介：Inthispaper,onthebasisofthephase-shiftedcontrolledzero-voltage-switch(ZVS)full-bridgeconverterwithpulsewidthmodulation(PWM),anovelzero-voltageandzero-currentswitch(ZVZCS)PWMconverterusingasimpleauxiliarycircuitwasdesigned.TheZVZCSsoftswitchisachievedbytheresonanceamongtheresistingelectromagneticdeflectioncapacitor,thecapacitorofthesimpleauxiliarynetworkandtheleakageinductoroftransformer.Therearenodissipationdevicesofthesaturationinductorandtheauxiliaryswitchintheconverter,meantimethecapacitoroftheauxiliarycircuitisalsousedtoclampthevoltageoftherectifier,andthereisnoadditionalclampedcircuit.Thereisnobigcirculatingcurrentintheconverter,alltheactiveandpassivedevicesworkontheconditionofthelowcurrentandvoltagestress,andtheproposedconverterhaswideloadrangeandsmalldutyloss.

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简介：Numericalsimulationconcerningtheformingandweldingprocessofspiralweldedpipewasconducted,whichincludedthreesteps:thefirststepwasthestressanalysiswhenthespiralwasformed,andthenthestresswasregardedasinitialconditionofmeldingduringthetemperaturefieldanalysisintheprocessofwelding,thelaststepwasthethermalstressanalysisoftheweldseamaftertheweldingwasover.Moreover,whenthesteelstripwaspushed,thestresswasalsocalculatedbynon-linearitycontacttechnologyusingAbaqusSoftware.Byfiniteelementmodelingandcalculatingoftheformingandweldingprocessofthespiralweldedpipe,thekeypointsofthemulti-fieldssyntheticsimulatingwerestudiedanddiscussed.

简介：Ａｎａｌｙｓｉｓｏｎｍｅｃｈａｎｉｓｍｏｆａｘｉａｌｄｒｉｆｔｉｎｇｏｆｃｙｌｉｎｄｅｒｗｏｒｋｐｉｅｃｅｏｎｗｅｌｄｉｎｇｒｏｌｌｅｒｂｅｄ￥ＳＨＥＮＦｅｎｇｇａｎｇ；ＰＡＮＸｉｄｅ；ＸＵＥＪｉｎａｎｄＷＡＨＧＺｈｅｎｇ（ＷｅｌｄｉｎｇＲｅｓｅａｒ...

简介：Inthiswork,thewettability,agingandshearpropertiesofanewtypeoflead-freesolderpasteSn-07Ag-05Cu+BiNi(SACBN07)wasinvestigatedbyconductingaseriesofcomparisonexperimentswithSAC305andSAC0307solderpaste.TheresultsshowthatwettabilityofSACBN07isalmostequaltoSAC305,andbetterthanthatofSAC0307solderpaste.Thethicknessofintermetalliccompound(IMC)layerinSACBN07/Cuislowerthanthatofothertwotypesofsolderjointafteraging.AndCu_3SnlayerofSACBN07/CuisthinnerthanthatofSAC305andSAC0307.Inaddition,theSACBN07solderjointsperformthebestshearstrengthamongthesethreetypesofsolderpastes.

简介：ＭｅｃｈａｎｉｃａｌｓｔｒｅｎｇｔｈａｎａｌｙｓｉｓｏｆＳＭＴｓｏｌｄｅｒｊｏｉｎｔｓｂｙｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄ￥ＷＡＮＧＣｈｕｎｑｉｎｇ；ＷＡＮＧＲｕｉｊｕｎ；ＳＡＮＧＹａｎａｎｄＱＩＡＮＹｉｙｕ（ＷｅｌｄｉｎｇＤｅｐａｒｔｍｅｎｔ...

简介：Ｅｎｅｒｇｙｔｒａｎｓｆｏｒｍａｔｉｏｎａｎａｌｙｓｉｓｄｕｒｉｎｇｆｒｉｃｔｉｏｎｗｅｌｄｉｎｇｏｆｓｕｐｅｒａｌｌｏｙｌｎｃｏｎｅｌ７１８ＤｕａｎＬｉｙｕ；ＤｕＳｕｉｇｅｎｇ；ＳｈｉＷｅｉｑｉｎｇ；ＹｉａｎＪｕｎｈｕｉａｎｄＰａｎｇＹｕｎｈｏｎｇ...

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简介：Thedissolutionkineticsofvanadiumtrioxideinsulphuricacid-oxygenmediumwasexamined.Itwasdeterminedthattheconcentrationofsulphuricacidandstirringspeedabove800rmin1didnotsignificantlyaffectvanadiumextraction.Thedissolutionrateincreasedwithincreasingtemperatureandoxygenpartialpressure,butdecreasedwithincreasingparticlesize.Thedissolutionkineticswascontrolledbythechemicalreactionatthesurfacewiththeestimatedactivationenergyof43.46kJ·mol-1.Thel...

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简介：Aimingattheweldingconditionofspacecomplexseamisuncertainandtheintelligenceofweldingrobotisunideal,atwo-wheeledmobilerobotisdeveloped.Itnotonlyhasthecapacityofautonomousdecisionandavoidingobstacles,butalsocanflexiblymoveandstronglyadaptvariableenvironment.Thecompositionoftheweldingrobotisdescribedandthedynamicmodelisestablished.Thefeasiblecontrolstrategyandcontrolalgorithmisputforward.Thesimulationexperimentsofrealworldareconducted,theresultsaresatisfying.

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