简介：AdesignofthemainAC/DCconvertersystemforITERisdescribedandthecon-figurationofthemainAC/DCconvertersispresented.Toreducethereactivepowerabsorbedfromtheconverterunits,themainAC/DCconvertersaredesignedtobeseries-connectedandworkinasequentialmode.Thestructureoftheregulatoroftheconvertersystemisdescribed.AsimulationmodelwasbuiltupforthePSCAD/EMTDCcode,andthedesignwasvalidatedaccordingly.Harmonicanalysisandreactivepowercalculationoftheconvertersunitsarepresented.Theresultsrevealtheadvantageofsequentialcontrolinreducingreactivepowerandharmonics.

简介：Magnetohydrodynamic(MHD)acceleratorisproposedasanextgenerationpropulsionsystem.Itcanbeusedtoincreasetheperformanceofapropulsionsystem.TheobjectiveofthisstudyistoinvestigatetheperformanceofMHDacceleratorusingnon-equilibriumairplasmaasworkinggas.Inthisstudy,thefundamentalperformanceofMHDacceleratorsuchasflowperformanceandelectricalperformanceisevaluatedatdifferentlevelsofappliedmagneticfieldusing1-Dnumericalsimulation.ThenumericalsimulationisdevelopedbasedonasetofdifferentialequationswithMHDapproximation.TosolvethissetofdifferentialequationstheMacCormackschemeisused.AspecifiedchanneldesignedanddevelopedatNASAMarshallSpaceFlightCentreisusedinthenumericalsimulation.Thecompositionofthesimulatedairplasmaconsistsofsevenspecies,namely,N2,N,O2,O,NO,NO+,ande-.Theperformanceofthenon-equilibriumMHDacceleratorisalsocomparedwiththeequilibriumMHDaccelerator.

简介：Intheplasmasheathanarrowplasmachannelgeneratedbyultraintenselaserpulsesissimplifiedasaspecialcylindricalandhollowplasmawaveguidewiththeinfinitethicknessoftheplasmacladding.Theelectromagneticwave(EM)propagationpropertiesoftheplasmachannelnearthecutoffandfarfromthecutoffareconsidered.TheoreticalanalysisshowsthatTE0mandTM0mandhybridmodesemergeintheplasmachannel,whichisinfluencedbythenormalizedfrequencyparameterBandnumericalapertureNA.Thecutoffsofthevariousmodesareapproximated.Single-modeoperationispossiblewithoutahigh-frequencylimitationinthechannel.

简介：Chemicalvapordeposition-tungsten(CVD-W)coatingcoveringthesurfaceoftheplasmafacingcomponent(PFC)isaneffectivemethodtoimplementthetungstenmaterialasplasmafacingmaterial(PFM)infusiondevices.ResidualthermalstressinCVD-Wcoatingduetothermalmismatchbetweencoatingandsubstratewassuccessfullysimulatedbyusingafiniteelementmethod(ANSYS10.0code).Thedepositionparametriceffects,i.e.,coatingthicknessanddepositiontemperature,andinterlayerwereinvestigatedtogetadescriptionoftheresidualthermalstressintheCVD-Wcoating-substratesystem.AndtheinfluenceofthesubstratematerialsonthegenerationofresidualthermalstressintheCVD-WcoatingwasanalyzedwithrespecttotheCVD-WcoatingapplicationasPFM.ThisanalysisisbeneficialforthepreparationandapplicationofCVD-Wcoating.

简介：Thegeometryofaninductivelycoupledplasma(ICP)etcherisusuallyconsideredtobeanimportantfactorfordeterminingbothplasmaandprocessuniformityoveralargewafer.Duringthepastfewdecades,theseparametersweredeterminedbythe'trialanderror'method,resultinginwastesoftimeandfunds.Inthispaper,anewapproachofregressionorthogonaldesignwithplasmasimulationexperimentsisproposedtoinvestigatethesensitivityofthestructuralparametersontheuniformityofplasmacharacteristics.ThetoolforsimulatingplasmaisCFD-ACE+,whichiscommercialmulti-physicalmodelingsoftwarethathasbeenproventobeaccurateforplasmasimulation.Thesimulatedexperimentalresultsareanalyzedtogetaregressionequationonthreestructuralparameters.Throughthisequation,engineerscancomputetheuni-formityoftheelectronnumberdensityrapidlywithoutmodelingbyCFD-ACE+.Anoptimizationperformedattheendproducesgoodresults.

简介：Opticalemissionspectroscopy(OES)wasappliedforplasmacharacterizationduringtheerosionofasphaltenesubstrates.Anamountof100mgofasphaltenewascarefullyappliedtoanelectrodeandexposedtoair-plasmaglowdischargeatapressureof1.0Torr.Theplasmawasgeneratedinastainlesssteeldischargechamberbyanacgeneratoratafrequencyof60Hz,outputpowerof50Wandagasflowrateof1.8L/min.Theelectrontemperatureandiondensitywereestimatedtobe2.15±0.11eVand(1.24±0.05)×1016m-3,respectively,usingadoubleLangmuirprobe.OESwasemployedtoobservetheemissionfromtheasphalteneexposedtoairplasma.BothmolecularbandemissionfromN2,N+2,OH,CH,NH,O2aswellasCN,andatomiclightemissionfromVandHγwereobservedandusedtomonitortheevolutionofasphalteneerosion.Theasphalteneerosionwasanalyzedwiththeaidofascanningelectronmicroscope(SEM)equippedwithanenergydispersiveX-ray(EDX)detector.TheEDXanalysisshowedthatthetimeevolutionofelementsC,O,SandVweresimilar;andthechemicalcompositionoftheexposedasphaltenesremainedconstant.Particlesizeevolutionwasmeasured,showingamaximumsizeof2307μmafter60min.Thisbehaviorismostlikelyrelatedtoparticleagglomerationasafunctionoftime.

简介：Athreedimensionalsteady-statemagnetohydrodynamicmodelisdevelopedforthearcplasmainaDCsubmergedelectricarcfurnacefortheproductionoffusedMgO.Thearcisgeneratedinasmallsemi-enclosedspaceformedbythegraphiteelectrode,themoltenbathandunmeltedrawmaterials.Themodelisfirstusedtosolveasimilarprobleminasteelmakingfurnace,andthecalculatedresultsarefoundtobeingoodagreementwiththepublishedmeasurements.ThebehaviorofarcswithdifferentarclengthsisalsostudiedinthefurnaceforMgOproduction.Fromthedistributionofthearcpressureonthebathsurfaceitisshownthatthearcplasmaimpingementislargeenoughtocauseacrater-likedepressiononthesurfaceoftheMgObath.Thecirculationofthehightemperatureairundertheelectrodemayenhancethearcefficiency,especiallyforashorterarc.