简介:AfewCT-basedvoxelphantomswereproducedtoinvestigatethesensitivityofMonteCarlosimulationsofX-raybeamandelectronbeamtotheproportionsofelementsandthemassdensitiesofthematerialsusedtoexpressthepatient'sanatomicalstructure.Thehumanbodycanbewelloutlinedbyair,lung,adipose,muscle,softboneandhardbonetocalculatethedosedistributionwithMonteCarlomethod.TheeffectsofthecalibrationcurvesestablishedbyusingvariousCTscannersarenotclinicallysignificantbasedonourinvestigation.ThedeviationfromthevaluesofcumulativedosevolumehistogramderivedfromCT-basedvoxelphantomsislessthan1%forthegiventarget.
简介:Asanimportantnon-ferrousmetalstructuralmaterialmostusedinindustryandproduction,aluminum(Al)alloyshowsitsgreatvalueinthenationaleconomyandindustrialmanufacturing.HowtoclassifyAlalloyrapidlyandaccuratelyisasignificant,popularandmeaningfultask.Classificationmethodsbasedonlaser-inducedbreakdownspectroscopy(LIBS)havebeenreportedinrecentyears.AlthoughLIBSisanadvanceddetectiontechnology,itisnecessarytocombineitwithsomealgorithmtoreachthegoalofrapidandaccurateclassification.Asanimportantmachinelearningmethod,therandomforest(RF)algorithmplaysagreatroleinpatternrecognitionandmaterialclassification.ThispaperintroducesarapidclassificationmethodofAlalloybasedonLIBSandtheRFalgorithm.TheresultsshowthatthebestaccuracythatcanbereachedusingthismethodtoclassifyAlalloysamplesis98.59%,theaverageofwhichis98.45%.ItalsorevealsthroughtherelationshiplawsthattheaccuracyvarieswiththenumberoftreesintheRFandthesizeofthetrainingsamplesetintheRF.Accordingtothelaws,researcherscanfindouttheoptimizedparametersintheRFalgorithminordertoachieve,asexpected,agoodresult.TheseresultsprovethatLIBSwiththeRFalgorithmcanexactlyclassifyAlalloyeffectively,preciselyandrapidlywithhighaccuracy,whichobviouslyhassignificantpracticalvalue.
简介:Theaccuracyoflaser-inducedbreakdownspectroscopy(LIBS)quantitativemethodisgreatlydependentontheamountofcertifiedstandardsamplesusedfortraining.However,inpracticalapplications,onlylimitedstandardsampleswithlabeledcertifiedconcentrationsareavailable.Anovelsemi-supervisedLIBSquantitativeanalysismethodisproposed,basedonco-trainingregressionmodelwithselectionofeffectiveunlabeledsamples.Themainideaoftheproposedmethodistoobtainbetterregressionperformancebyaddingeffectiveunlabeledsamplesinsemi-supervisedlearning.First,effectiveunlabeledsamplesareselectedaccordingtothetestingsamplesbyEuclideanmetric.Twooriginalregressionmodelsbasedonleastsquaressupportvectormachinewithdifferentparametersaretrainedbythelabeledsamplesseparately,andthentheeffectiveunlabeledsamplespredictedbythetwomodelsareusedtoenlargethetrainingdatasetbasedonlabelingconfidenceestimation.Thefinalpredictionsoftheproposedmethodonthetestingsampleswillbedeterminedbyweightedcombinationsofthepredictionsoftwoupdatedregressionmodels.Chromiumconcentrationanalysisexperimentsof23certifiedstandardhigh-alloysteelsampleswerecarriedout,inwhich5sampleswithlabeledconcentrationsand11unlabeledsampleswereusedtotraintheregressionmodelsandtheremaining7sampleswereusedfortesting.Withthenumbersofeffectiveunlabeledsamplesincreasing,therootmeansquareerroroftheproposedmethodwentdownfrom1.80%to0.84%andtherelativepredictionerrorwasreducedfrom9.15%to4.04%.
简介:ApoolcooledexperimentalmagnetbasedonthecopperstabilizedNbTisuperconductingwirewasdesigned,fabricatedandtested,inordertoevaluatetheengineeringdesignofthedipolesuperconductingmagnetforthecollectorring(CR)ofthefacilityforantiprotonandionresearch(FAIR)project.Inthispaper,theexperimentalsetupincludingquenchprotectionsystemwaspresented.Performanceoftheliquidheliumpoolcooledtestwasintroduced.Alloftheresultsindicateboththeperformanceofconductorandtheexperimentalsuperconductingmagnetunderlowtemperatureisstable,whichsuggeststheengineeringdesignarefeasiblefortheformalmagnetinCRoftheFAIRproject.
简介:Thetriple-to-doublecoincidenceratio(TDCR)methodofliquidscintillationcount-ingisanabsolutemeasurementmethodofradioactivity.TheformulationoftheTDCRmethodandtheestablishedTDCRliquidscintillationcounterarepresentedinthispaper.TheNISTstandardreferencematerial(SRM)oftritiumwaterwasmeasuredtoverifytheperformanceoftheTDCRliquidscintillationcounter.
简介:An8-channelHCNlaserinterferometerwillbeinstalledonHL-2Ainnearterm.InordertogetthespatialprofileoftheelectrondensityBarrnumericalmethodisadoptedtorealizetheAbelinversion.InthisarticletheresultoftheAbelinversionbyMatlabGUIisgivenwhichcanbeupdatedtoprocessthemeasureddataofthe8-channellaserinterferometerandprovidethespatialdistributionoftheelectrondensity.
简介:Inapoloidalfield(PF)convertermodule,fuseprotectionisofgreatimportancetoensurethesafetyofthethyristors.Thefuseispre-selectedinatraditionalwayandthenverifiedbyfiniteelementanalysis.A3DphysicalmodelisbuiltbyANSYSsoftwaretosolvethethermalelectriccoupledproblemoftransientprocessincaseofexternalfault.Theresultshowsthatthismethodisfeasible.
简介:Implementationofaweb-basedlogbooksystemonEASTisintroduced,whichcanstorethecommentsfortheexperimentsintoadatabaseandaccessthedocumentsviavariouswebbrowsers.Thethree-tiersoftwarearchitectureandasynchronousaccesstechnologyareadoptedtoimprovethesystemeffectively.Authorizeduserscanviewtheinformationofreal-timedischarge,commentsfromothersandsignalplots;add,delete,orrevisetheirowncomments;searchsignaldataorcommentsundercomplicatedsearchconditions;andcollectrelevantinformationandoutputittoanexcelfile.Thewebpagescanbeautomaticallyupdatedafteranewdischargeiscompletedandwithoutrefreshment.
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简介:Theneutronfluxmonitor(NFM),asasignificantdiagnosticsystemintheInternationalThermonuclearExperimentalReactor(ITER),willplayanimportantroleinthereadingsofaseriesofkeyparametersinthefusionreactionprocess.AsthecoreofthemainelectronicsystemoftheNFM,theneutron-gammapulseshapediscrimination(n-γPSD)candistinguishtheneutronpulsefromthegammapulseandotherdisturbingpulsesaccordingtothethresholdsoftherisingtimeandtheamplitudepre-installedontheboard,thedoubletimingpointCFDmethodisusedtogettherisingtimeofthepulse.Then-γPSDcanprovideanaccurateneutroncount.
简介:Athreedimensionalbounce-averagedFokker-Planck(FP)numericalcodehasbeennewlydevelopedbasedonfullyimplicititerativesolvingmethod,andrelativisticeffectisalsoincludedinthecode.Thecodehasbeentestedagainstvariousbenchmarkcases:OhmicconductivityinthepresenceofweakOhmicelectricfield,runawaylossesofelectronsinthepresenceofstrongOhmicelectricfield,lowerhybridcurrentdriveandelectroncyclotroncurrentdriveviatwo-orthree-dimensionalsimulation.Allthetestcasesrunfastandcorrectlyduringcalculations.Asaresult,thecodeprovidesasetofpowerfultoolsforstudyingradiofrequencywaveheatingandcurrentdriveintokamakplasmas.
简介:Non-contactmagneticmeasurementmethodisaneffectivewaytostudytheairarcbehaviorexperimentally.Oneofthecrucialtechniquesistosolveaninverseproblemfortheelectromagneticfield.Thisstudyisdevotedtoinvestigatingdifferentalgorithmsforthiskindofinverseproblempreliminarily,includingthepreconditionedconjugategradientmethod,penaltyfunctionmethodandgeneticalgorithm.Thefeasibilityofeachalgorithmisanalyzed.Itisshownthatthepreconditionedconjugategradientmethodisvalidonlyforfewarcsegments,theestimationaccuracyofthepenaltyfunctionmethodisdependentontheinitialconditions,andtheconvergenceofgeneticalgorithmshouldbestudiedfurtherformoresegmentsinanarccurrent.
简介:Neutrondiagnostics,includingfluxandenergyspectrummeasurements,havebeenappliedontheexperimentaladvancedsuperconductingtokamak(EAST).TheabsolutecalibrationofneutronyieldshasbeenachievedbyacalculationmethodusingtheMonteCarloautomaticmodeling(MCAM)systemandtheMonteCarloN-Particles(MCNP)code.Sincetheneutronyieldiscloselyrelatedwiththeiondensityandtemperature,itisagoodmeasureofplasmaperformance,especiallythewaveheatingeffect.Inioncyclotronrangeoffrequencies(ICRF)experiments,theincreaseintheiontemperaturederivedbytheneutronyieldindicatesaneffectiveplasmaheating.Minorityprotonsdampalargefractionofthetotalwavepower,andthentransferpartoftheenergytodeuteriumbycollisions.NeutronspectrummeasurementsalsoindicatethatnotailiscreatedbyhighenergydeuteronsduringICRFheating.However,theiontemperaturederivedbytheneutronyieldisconsistentwiththeresultbyusingapoloidalX-rayimagingcrystalspectrometer(PXCS),showingareliabletransportcalculation.
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简介:Atriggerdeviceandatriggeredpseudosparkswitch(TPSS)weredesignedbasedonsurfaceflashovertechnology,inordertomeettherequirementsfrompresentpulsepowertechnol-ogyandpulsecurrenttesttechnologysuchasalonglifetime,reliabilityinawidevoltagerange,ashortdelaytime,aswellassmalldelayjitters.Thetriggerdevicesweremadefromdifferentdielectricmaterials,withtheirpermittivitiesfromtenstothousands.ThetriggercharacteristicsofTPSSwereinvestigated.Theresultsindicatethatthehigh-dielectrictriggerdeviceshowsbetterperformanceandhigheremittedchargeoftheelectronemissionwithinalladjustedparametersincludingthegaspressureandappliedvoltage.Forthedielectricmaterialwithrelativepermittiv-ityε_rof3460,whenthegaspressureis7Pa,thehold-offvoltageofTPSSis28kV,theminimumtriggerswitchvoltagedropsto128V,theminimumdischargingdelaytimeanddelayjitterarelessthan35nsand6ns,respectively,andthereliableoperationcanbereachedwithinaverylargerangeofchargingvoltage,between0.46%and99%ofitsself-breakdownvoltage.
简介:Breakdowncharacteristicsofagapbreakdownloadwasinvestigatedinthispaper,andareverselyswitcheddynistor(RSD)dischargecircuitwasdesignedbasedontheload.Basedonthecharacteristicsoftheload,theRSDdischargecircuitwasimprovedandoptimized.Thevolumeofthemagneticswitchwasreduced.ToprotectthethyristorandRSD,adiodewasantiparallelyconnectedwiththethyristor,whichreducedthetimerequirementwhenapowervoltagewasappliedtoRSD.Experimentalresultsshowthecircuitdesignedinthispapercanswitchahighvoltageandhighcurrentsmoothly,andallowsthepowervoltagetochangeinawiderrange.
简介:Amulti-objectivehybridgeneticbasedoptimizationalgorithmisproposedaccordingtothemulti-objectivePropertyofinverseplanning.Itisbasedonhybridadaptivegeneticalgorithmwhichcombinesthesimulatedannealing,usesadaptivecrossoverandmutation,andadoptsnichedtournamentselection.Theresultoftheteatcalculatationdemonstratesthatanexcellentconvergingspeedcanbeachievedusingthisapproach.
简介:Ageneratoroftheglidingarcjet(GAJ),whichisdrivenbyatransversemagneticfield,isdevelopedtoproducenon-equilibriumplasmaatatmosphericpressure.ThegastemperatureisestimatedusingthespectrumofOHradicalstobeabout2400±400K.Thedeterminationsofelectrontemperatureandelectrondensitybyusingaline-ratiomethodareelaboratedfortheglidingarcjetplasma.Thisline-ratiomethodisbasedonacollisional-radiativemodel.Theexperimentresultsshowthatelectrontemperatureisabout1.0eVandelectrondensityisabout6.9×1014cm-3.Obviously,theplasmaofGAJisinanon-equilibriumstate.