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.

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简介：AfewCT-basedvoxelphantomswereproducedtoinvestigatethesensitivityofMonteCarlosimulationsofX-raybeamandelectronbeamtotheproportionsofelementsandthemassdensitiesofthematerialsusedtoexpressthepatient'sanatomicalstructure.Thehumanbodycanbewelloutlinedbyair,lung,adipose,muscle,softboneandhardbonetocalculatethedosedistributionwithMonteCarlomethod.TheeffectsofthecalibrationcurvesestablishedbyusingvariousCTscannersarenotclinicallysignificantbasedonourinvestigation.ThedeviationfromthevaluesofcumulativedosevolumehistogramderivedfromCT-basedvoxelphantomsislessthan1%forthegiventarget.

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.

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简介：Non-contactmagneticmeasurementmethodisaneffectivewaytostudytheairarcbehaviorexperimentally.Oneofthecrucialtechniquesistosolveaninverseproblemfortheelectromagneticfield.Thisstudyisdevotedtoinvestigatingdifferentalgorithmsforthiskindofinverseproblempreliminarily,includingthepreconditionedconjugategradientmethod,penaltyfunctionmethodandgeneticalgorithm.Thefeasibilityofeachalgorithmisanalyzed.Itisshownthatthepreconditionedconjugategradientmethodisvalidonlyforfewarcsegments,theestimationaccuracyofthepenaltyfunctionmethodisdependentontheinitialconditions,andtheconvergenceofgeneticalgorithmshouldbestudiedfurtherformoresegmentsinanarccurrent.

简介：Ageneratoroftheglidingarcjet(GAJ),whichisdrivenbyatransversemagneticfield,isdevelopedtoproducenon-equilibriumplasmaatatmosphericpressure.ThegastemperatureisestimatedusingthespectrumofOHradicalstobeabout2400±400K.Thedeterminationsofelectrontemperatureandelectrondensitybyusingaline-ratiomethodareelaboratedfortheglidingarcjetplasma.Thisline-ratiomethodisbasedonacollisional-radiativemodel.Theexperimentresultsshowthatelectrontemperatureisabout1.0eVandelectrondensityisabout6.9×1014cm-3.Obviously,theplasmaofGAJisinanon-equilibriumstate.

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简介：TheprecisionofplasmaelectrondensityandFaradayrotationanglemeasurementisakeyindicatorforfar-infraredlaserinterferometer/polarimeterplasmadiagnosis.Toimprovetheprecision,anewmulti-channelhighsignal-to-noiseratioHCOOHinterferometer/polarimeterhasbeendevelopedontheHL-2Atokamak.Ithasahigherlevelrequirementforphasedemodulationprecision.Thispaperintroducesanimprovedreal-timefastFouriertransformalgorithmbasedonthefieldprogrammablegatearray,whichsignificantlyimprovestheprecision.Wealsoapplyareal-timeerrormonitoringmodule(REMM)andastableerrorinhibitingmodule(SEIM)forprecisioncontroltodealwiththeweaksignal.Wetesttheinterferometer/polarimetersystemwiththisimprovedprecisioncontrolmethodinplasmadischargeexperimentsandsimulationexperiments.Theexperimentalresultsconfirmthattheplasmaelectrondensityprecisionisbetterthan1/3600fringeandtheFaradayrotationanglemeasurementprecisionisbetterthan1/900fringe,whilethetemporalresolutionis80ns.ThisperformancecanfullymeettherequirementsofHL-2A.

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简介：Opticalemissionspectroscopy(OES)usingthetraceraregasesofArandXehavebeencarriedoutinaradiofrequency(RF)drivennegativeionsourceatInstituteofPlasmaPhysics,ChineseAcademyofScience(ASIPP),inordertodeterminetheelectrontemperatureanddensityofthehydrogenplasma.Theline-ratiomethodsbasedonpopulationmodelsareappliedtodescribetheradiationprocessoftheexcitedstateparticlesandestablishtheirrelationswiththeplasmaparameters.Thespectrallinesfromtheargonandxenonexcitedstateatomswiththewavelengthof750.4and828.0nmareusedtocalculatetheelectrontemperaturebasedonthecoronamodel.Theargonionsemissionlineswiththewavelengthof480and488nmareselectedtocalculatetheelectrondensitybasedonthecollisionalradiativemodel.OEShasgiventhepreliminaryresultsoftheelectrontemperatureanddensitybyvaryingthedischargegaspressureandRFpower.Accordingtotheexperimentalresults,thetypicalplasmaparametersisTe2≈2-4eVandne≈1x1017-8x1017m^-3infrontofplasmagrid.

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%.