学科分类
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10 个结果
  • 简介:Theoreticalbeamintensitydistributionisderivedfortheneutral-beam-injectionionsourcewithamulti-slotextractioninEAST.Thebeamintensityprofile,bothalongandperpendiculartotheinjectingdirectionandthebeampowerdepositiontotheinnerelementsintheneutralbeaminjector(NBI)areevaluated.Theresultsindicatethatthetransversebeamintensityismuchhigherthanthelongitudinalone.Thisstudycouldprovideinformationforthedesignofvacuumsystem,structureofinnerelementsandcoolingsystemoftheneutralbeaminjectorinEAST.

  • 标签: 中性束注入器 强度分布 冷却系统设计 真空系统 离子源
  • 简介:Thetransportprocessof12CionsinwaterwasstudiedwithSRIMcodeandGeant4toolkit.TheSRIMresultsindicatethatthetransversediffusionof12Cionbeamcausesdistortionofenergydepositalongthebeamdirection.Thedistortionbecomesmorenotableasthetrans-versediffusionincreases.ThesimulationresultsofGeant4indicatethattheinfluenceofsecondaryfragmentsonenergydepositdistributionwouldbethemainfactorcausingthedistortioninhigherenergyrange.Intheregionadjacenttothebeamlinewherethecontributionfrom12Cionsdomi-nates,thecontributionsfromsecondaryfragmentsareignorable.Thefurtherfromthebeamaxistheregionlocates,thelargerthecontributionsfromsecondaryfragments,untilthecontributionsfromsecondaryfragmentsareignorable.Thefurtherfromthebeamaxistheregionlocates,thelargerthecontributionsfromsecondaryfragments,untilthecontributionsfromsecondaryfrag-mentsexceedthatof12C.Amongallthesecondaryfragments,thecontributionsofH,HeandBionsaremostlynotable.Itisalsofoundthatsomepositron-emittingsecondaryfragmentscouldbeveryusefulforpositionemittingtomography(PET).

  • 标签: 能量沉积分布 离子水 GEANT4 正电子发射 扭曲 SRIM
  • 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.

  • 标签: 电压分布特性 混合式断路器 高电流 中断 真空灭弧室 瞬态恢复电压
  • 简介:AfewCT-basedvoxelphantomswereproducedtoinvestigatethesensitivityofMonteCarlosimulationsofX-raybeamandelectronbeamtotheproportionsofelementsandthemassdensitiesofthematerialsusedtoexpressthepatient'sanatomicalstructure.Thehumanbodycanbewelloutlinedbyair,lung,adipose,muscle,softboneandhardbonetocalculatethedosedistributionwithMonteCarlomethod.TheeffectsofthecalibrationcurvesestablishedbyusingvariousCTscannersarenotclinicallysignificantbasedonourinvestigation.ThedeviationfromthevaluesofcumulativedosevolumehistogramderivedfromCT-basedvoxelphantomsislessthan1%forthegiventarget.

  • 标签: 蒙特卡洛法 核辐射 临界分布计算 标定曲线 计算机断层摄影
  • 简介:Tomakethelarge-scaleheliumcryogenicsystemoffusiondeviceEAST(experimentaladvancedsuper-conductingtokamak)runstably,asthecorepart,theheliumturbineexpandermustmeettherequirementofrefrigerationcapacity.However,previousdesignswerebasedononedimensionflowtodeterminetheaveragefluidparametersandgeometricparametersofimpellercross-sections,sothatitcouldnotdescriberealphysicalprocessesintheinternalflowoftheturbineexpander.Therefore,basedontheinversepropositionofstreamlinecurvaturemethodinthecontextofquasi-three-dimensionalflows,theall-over-controlledvortexconceptwasadoptedtodesigntheimpellerunderspecifiedcondition.Thewrapangleoftheimpellerbladeandthewholeflowdistributiononthemeridianplanewereobtained;meanwhiletheperformanceofthedesignedimpellerwasanalyzed.Thusanewdesignmethodisproposedherefortheinversepropositionoftheheliumturbineexpanderimpeller.

  • 标签: 透平膨胀机 叶轮叶片 设计方法 控制 超导托卡马克
  • 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.

  • 标签: 等离子体聚焦 速度 磁探测器 立体 前护套 充电电压
  • 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.

  • 标签: 颗粒粒径分布 非热等离子体 柴油机 成分 间接 低温等离子体技术
  • 简介:AnovelfittingprocedureisproposedforabetterdeterminationofH2rovibrationaldistributionfromtheFulcher-abandspectroscopy.WehaverecalculatedthetransitionprobabilitiesandtheresultsshowthattheydeviatefromFranck-Condonapproximationespeciallyforthenon-diagonaltransitions.Wealsocalculatedthecompletesetsofvibrationallyresolvedcrosssectionsforelectronimpactd3∏u-X3∑gtransitionbasedonthesemi-classicalGryzinskitheory.AnexampleofexperimentalstudyconfirmsthatcurrentapproachprovidesatoolforabetterdiagnosticsofH2rovibrationaldistributioninelectronicgroundstate.

  • 标签: 低温等离子体 转振激发 氢气分子 Fulcher-α波段分光镜