简介:Theoreticalbeamintensitydistributionisderivedfortheneutral-beam-injectionionsourcewithamulti-slotextractioninEAST.Thebeamintensityprofile,bothalongandperpendiculartotheinjectingdirectionandthebeampowerdepositiontotheinnerelementsintheneutralbeaminjector(NBI)areevaluated.Theresultsindicatethatthetransversebeamintensityismuchhigherthanthelongitudinalone.Thisstudycouldprovideinformationforthedesignofvacuumsystem,structureofinnerelementsandcoolingsystemoftheneutralbeaminjectorinEAST.
简介:Thetransportprocessof12CionsinwaterwasstudiedwithSRIMcodeandGeant4toolkit.TheSRIMresultsindicatethatthetransversediffusionof12Cionbeamcausesdistortionofenergydepositalongthebeamdirection.Thedistortionbecomesmorenotableasthetrans-versediffusionincreases.ThesimulationresultsofGeant4indicatethattheinfluenceofsecondaryfragmentsonenergydepositdistributionwouldbethemainfactorcausingthedistortioninhigherenergyrange.Intheregionadjacenttothebeamlinewherethecontributionfrom12Cionsdomi-nates,thecontributionsfromsecondaryfragmentsareignorable.Thefurtherfromthebeamaxistheregionlocates,thelargerthecontributionsfromsecondaryfragments,untilthecontributionsfromsecondaryfragmentsareignorable.Thefurtherfromthebeamaxistheregionlocates,thelargerthecontributionsfromsecondaryfragments,untilthecontributionsfromsecondaryfrag-mentsexceedthatof12C.Amongallthesecondaryfragments,thecontributionsofH,HeandBionsaremostlynotable.Itisalsofoundthatsomepositron-emittingsecondaryfragmentscouldbeveryusefulforpositionemittingtomography(PET).
简介:Hybridcircuitbreaker(HCB)technologybasedonavacuuminterrupterandaSF6interrupterinserieshasbecomeanewresearchdirectionbecauseofthelow-carbonrequirementsforhighvoltageswitches.Thevacuuminterrupterhasanexcellentabilitytodealwiththesteeprisingpartofthetransientrecoveryvoltage(TRV),whiletheSF6interruptercanwithstandthepeakpartofthevoltageeasily.AnHCBcantakeadvantageoftheinterruptersinthecurrentinterruptionprocess.Inthisstudy,anHCBmodelbasedonthevacuumiondiffusionequations,iondensityequation,andmodifiedCassie-Mayrarcequationisexplored.Asimulationplatformisconstructedbyusingasetofsoftwarecalledthealternativetransientprogram(ATP).AnHCBprototypeisalsodesigned,andtheshortcircuitcurrentisinterruptedbytheHCBunderdifferentactionsequencesofcontacts.ThevoltagedistributionoftheHCBisanalyzedthroughsimulationsandtests.TheresultsdemonstratethatifthevacuuminterrupterwithstandstheinitialTRVandinterruptsthepost-arccurrentfirst,thentherecoveryspeedofthedielectricstrengthoftheSF6interrupterwillbefast.Thevoltagedistributionbetweentwointerruptersisdeterminedbytheirpost-arcresistance,whichhappensaftercurrent-zero,andsubsequently,itisdeterminedbythecapacitiveimpedanceafterthepost-arccurrentdecaystozero.
简介:AfewCT-basedvoxelphantomswereproducedtoinvestigatethesensitivityofMonteCarlosimulationsofX-raybeamandelectronbeamtotheproportionsofelementsandthemassdensitiesofthematerialsusedtoexpressthepatient'sanatomicalstructure.Thehumanbodycanbewelloutlinedbyair,lung,adipose,muscle,softboneandhardbonetocalculatethedosedistributionwithMonteCarlomethod.TheeffectsofthecalibrationcurvesestablishedbyusingvariousCTscannersarenotclinicallysignificantbasedonourinvestigation.ThedeviationfromthevaluesofcumulativedosevolumehistogramderivedfromCT-basedvoxelphantomsislessthan1%forthegiventarget.
简介:Tomakethelarge-scaleheliumcryogenicsystemoffusiondeviceEAST(experimentaladvancedsuper-conductingtokamak)runstably,asthecorepart,theheliumturbineexpandermustmeettherequirementofrefrigerationcapacity.However,previousdesignswerebasedononedimensionflowtodeterminetheaveragefluidparametersandgeometricparametersofimpellercross-sections,sothatitcouldnotdescriberealphysicalprocessesintheinternalflowoftheturbineexpander.Therefore,basedontheinversepropositionofstreamlinecurvaturemethodinthecontextofquasi-three-dimensionalflows,theall-over-controlledvortexconceptwasadoptedtodesigntheimpellerunderspecifiedcondition.Thewrapangleoftheimpellerbladeandthewholeflowdistributiononthemeridianplanewereobtained;meanwhiletheperformanceofthedesignedimpellerwasanalyzed.Thusanewdesignmethodisproposedherefortheinversepropositionoftheheliumturbineexpanderimpeller.
简介:Thecurrentsheathvelocityin0.25TorrgaspressureofFilippovtypeplasmafocusisstudiedexperimentally.Byusingtwotridimensionalmagneticprobesontopoftheanodesurface,thecurrentsheathvelocityismeasuredforargon,oxygenandnitrogen.Additionally,theeffectofchargingvoltageonthecurrentsheathvelocityisstudiedinbothaxialandradialphases.Wefoundthat,themaximumcurrentsheathvelocitiesatbothradialandaxialphasesarerespectively4.33±0.28(cm/μs)and3.92±0.75(cm/μs)withargonastheworkinggasat17kV.Also,theminimumvaluesofcurrentsheathvelocityare1.48±0.15(cm/μs)attheradialphaseand1.14±0.09(cm/μs)attheaxialphasewithoxygenat12kV.Thecurrentsheathvelocityattheradialphaseishigherthanthatattheaxialphaseforallgasesandvoltages.Inthisstudy,variationofthefullwidthhalfmaximum(FWHM)ofmagneticprobesignalswithvoltageisinvestigatedfordifferentgasesatradialandaxialphases.
简介:Toexploretheeffectofthegassourceflowrateontheactualdieselexhaustparticulatematter(PM),atestbenchfordieselengineexhaustpurificationwasconstructed,usingindirectnonthermalplasmatechnology.Theeffectsofdifferentgassourceflowratesonthequantityconcentration,composition,andapparentactivationenergyofPMwereinvestigated,usinganengineexhaustparticlesizerandathermo-gravimetricanalyzer.Theresultsshowthatwhenthegassourceflowratewaslarge,notonlythemaximumpeakquantityconcentrationsofparticleshadalargedrop,butalsothepeakquantityconcentrationsshiftedtosmallerparticlesizesfrom100nmto80nm.Whenthegassourceflowratewas10Lmin~(-1),thetotalquantityconcentrationgreatlydecreasedwheretheremovalrateofparticleswas79.2%,andthevariationofthedifferentmodeparticleproportionwasobvious.Non-thermalplasma(NTP)improvedtheoxidationabilityofvolatilematteraswellasthatofsolidcarbon.However,theNTPgassourceratehadlittleeffectsonoxidationactivityofvolatilematter,whileitstronglyinfluencedtheoxidationactivityofsolidcarbon.Consideringthequantityconcentrationandoxidationactivityofparticles,agassourceflowrateof10Lmin~(-1)wasmoreappropriateforthepurificationofparticles.
简介:AnovelfittingprocedureisproposedforabetterdeterminationofH2rovibrationaldistributionfromtheFulcher-abandspectroscopy.WehaverecalculatedthetransitionprobabilitiesandtheresultsshowthattheydeviatefromFranck-Condonapproximationespeciallyforthenon-diagonaltransitions.Wealsocalculatedthecompletesetsofvibrationallyresolvedcrosssectionsforelectronimpactd3∏u-X3∑gtransitionbasedonthesemi-classicalGryzinskitheory.AnexampleofexperimentalstudyconfirmsthatcurrentapproachprovidesatoolforabetterdiagnosticsofH2rovibrationaldistributioninelectronicgroundstate.