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：Anexperimentalinvestigationofananosecondpulseddielectricbarrierdischargeinatmosphericairispresented.Inthesetupaquartztubewasinsertedbetweentheconeandplaneelectrodesinthedirectionparalleltotheelectricfield.Itwasshownthattheappearanceandpropertyofthedischargeweresensitivetothesizeandthepositionofthequartztube.Whenthetubewasplacedonthegroundedplaneelectrode,thedischargeintensitywasfoundtoimprovegraduallywiththeincreaseinthediameterofthequartztube.Furthermore,withanappropriatedistancebetweenthebottomedgeofthequartztubeandtheplaneelectrode,thedischargetendedtoexhibitbetterperformanceingeneratinghomogeneousdiffusiveplasma.Thepossiblemechanismisdiscussed.

简介：Lowtemperatureairplasmawasusedasthemutationtoolforpenicillin-producingstrainPenicilliumchrysogenum.ThedischargeconditionswereRFpowerof360W,temperatureof40℃inasealedchamber,andpressureof10Pato30Pa.Theresultshowedthatthekineticsofthesurvivalratefollowedatypicalsaddle-shapedcurve.Basedonastatisticanalysis,atthetreatingdurationof10min,thepositivemutationratewasashighas37.5%whilethenegativemutationratewaslow.Thecolonialmorphologychangedobviouslywhentheplasmatreatingdurationreachedorexceeded45min.Afterbothprimaryandsecondaryscreening,amutantdesignatedasaPc051310withhighproductivityofpenicillinwasobtained,andastrongmutageniceffectonP.chrysogenumwasobservedintheprocess.Itwasprovedthatafterfivegenerations,themutantaPc051310stillexhibitsahighproductivity.Alltheresultsprovethattheplasmamutationmethodcouldbedevelopedasaconvenientandeffectivetooltobreedhigh-yieldstrainsinthefermentationindustry,whileexpandingtheplasmapplicationatthesametime.

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：Inthiswork,laserinducedtungstenplasmahasbeeninvestigatedintheabsenceandpresenceof0.6Tstatictransversemagneticfieldatatmosphericpressureinair.Thespectroscopiccharacterizationoflaserinducedtungstenplasmawasexperimentallystudiedusingspace-resolvedemissionspectroscopy.Theatomicemissionlinesoftungstenshowedasignificantenhancementinthepresenceofamagneticfield,whiletheionicemissionlinesoftungstenpresentedlittlechange.Temporalvariationoftheopticalemissionlinesoftungstenindicatedthattheatomicemissiontimeinthepresenceofamagneticfieldwaslongerthanthatintheabsenceofamagneticfield,whilenosignificantchangesoccurredfortheionicemissiontime.Thespatialresolutionofopticalemissionlinesoftungstendemonstratedthatthespatialdistributionofatomsandionswereseparated.Theinfluenceofamagneticfieldonthespatialdistributionofatomswasremarkable,whereasthespatialdistributionofionswaslittleinfluencedbythemagneticfield.Thedifferentbehaviorsbetweenionsandatomswithandwithoutmagneticfieldinairwererelatedtothevariousatomicprocessesespeciallytheelectronsandionsrecombinationprocessduringtheplasmaexpansionandcoolingprocess.

简介：Inthispaper,a3Dmagneto-hydrodynamic(MHD)arcsimulationmodelisappliedtoanalyzethearcmotionduringcurrentinterruptioninacertainaircircuitbreaker(ACB).Thedistributionsofpressure,temperature,gasflowandcurrentdensityofthearcplasmainthearcregionarecalculated,andthefactorsinfluencingthecommutationprocessareanalyzedaccordingtothecalculatedresults.Basedontheairflowinthearcchamber,thecausesofarccommutationasynchronyandthebackcommutationareinvestigated.Itindicatesthatareasonablecontactspacedesigniscrucialtoasuccessfularccommutationprocess.Toverifythesimulationresults,theinfluenceofcontactspaceonarcvoltageandarccommutationistested.ThisresearchcanprovidemethodsandreferencestotheoptimizationofACBdesign.

简介：Effectsofdischargemode,voltageapplied,sizeofthenozzledischargeelectrodeandflowrateofwateronthegenerationofhydroxylradicalwereinvestigatedinairdischargewithatomizedwater,byusingopticalemissionspectroscopy(OES).Waterwasinjectedintothedischargeregionthroughthedischargenozzleelectrode,andalargeamountoffinewaterdrops,formedanddistributedinthedischargeregion,wereobserved.ItwasfoundthatnegativeDCcoronadischargewasmoreeffectivetogeneratethehydroxylradicalsincomparisontopositiveDCcoronadischargeornegativepulseddischarge.Alargerouterdiameterofthenozzleelectrodeorastrongerelectricfieldisbeneficialforhydroxyl-radicalgeneration.Moreover,thereisacriticalvalueintheflowrateofatomizedwateragainstthedischargevoltage.Belowthiscriticalvalue,hydroxyl-radicalgenerationincreaseswiththeincreaseinflowrateofthewater,whileabovethisvalue,itdecreases.Inaddition,itisobservedthatOESfromthedischargeismainlyintheultravioletdomain.Theresultsarehelpfulinthestudyofthemechanismandapplicationofplasmainpollution-controlineitherairorwater.

简介：Aninvestigationonthedischargecharacteristicofadielectricbarrierdischarge(DBD)devicewascarriedoutusingbareandZnO-coatedaluminadielectriclayerinatmosphericpressureair.HighlyconductiveZnOfilmwasfirstdepositedonthealuminasurface,andthecharacteristicsofthedielectricbarrierdischargewereexaminedandcompared.ExperimentalresultshowsthatdischargebehaviorwasdefinitelyimprovedinthecaseofZnO-coateddielectricbarrierdischarge.Relevantexplanationisofferedtodescribeitsdischargephysics.

简介：

简介：Alowpoweratmosphericpressureplasmajetdrivenbya24kHzACpowersourceandoperatedwithaCH4/airgasmixturehasbeeninvestigatedbyopticalemissionspectrometer.Theplasmaparametersincludingtheelectronexcitationtemperature,vibrationaltemperatureandrotationaltemperatureoftheplasmajetatdifferentdischargepowersarediagnosedbasedontheassumptionthatthekineticenergyofthespeciesobeystheBoltzmanndistribution.TheelectrondensityatdifferentpowerisalsoinvestigatedbyHβStarkbroadening.Theresultsshowthattheplasmasourceworksundernon-equilibriumconditions.Itisalsofoundthatthevibrationaltemperatureandrotationaltemperatureincreasewithdischargepower,whereastheelectronexcitationtemperatureseemstohaveadownwardtrend.Theelectrondensityincreasesfrom0.8×1021m-3to1.1×1021m-3whenthedischargepowerincreasesfrom53Wto94W.

简介：Dielectricbarrierdischarge(DBD)excitatedbypulsedpowerisapromisingmethodforproducingnonthermalplasmaatatmosphericpressure.DischargecharacteristicinaDBDwithsaltwateraselectrodesbyahome-madeunipolarnanosecond-pulsepowersourceispresentedinthispaper.Thegeneratoriscapableofprovidingrepetitivepulseswiththevoltageupto30kVanddurationof70nsata300Ωresistiveload.Appliedvoltageanddischargecurrentaremeasuredundervariousexperimentalconditions.TheDBDcreatedbetweentwoliquidelectrodesshowsthatthedischargeishomogeneousanddiffuseinthewholedischargeregime.Spectradiagnosisisconductedbyanopticalemissionspectroscopy.Theairplasmahasstrongemissionfromnitrogenspeciesbelow400nm,notablythenitrogensecondpositivesystem.

简介：Theobjectiveofthispaperistodemonstratewhetherairplasmacanchangetheseedgerminationcharacteristics,seedlingemergence,aswellasbiochemicalreactivity,inAndrographispaniculata(A.paniculata)seedlingsbymodifyingtheseedcoatandfindingabeneficialtreatmentdose.Eighttreatmentdosesandonecontrolwereusedtoconductelectricalconductivitydetermination,agerminationtest,aseedlingemergencetestandabiochemicalassay.Theresultsshowedthatafterbeingtreatedwithairplasmaexcitedat5950Vfor10s,thepermeabilityoftheseedswasimprovedsignificantly,resultingintheaccelerationofseedgerminationandseedlingemergence.Inthemeantime,thecatalaseactivityandcatalaseisoenzymeexpressionwerealsoimproved,whilethemalondialdehydecontentintheseedlingswasdecreased(whichmeansgreatercounteractionwithenvironmentalstress).Afterbeingtreatedwith4250Vfor10sand5950Vfor20s,theseedgerminationwasenhanced,butwithoutanobviouschangeinseedlingemergence.However,aftertreatmentwith3400Vfor20sand5100Vfor10s,thepermeabilityoftheseedswasdecreased,resultinginadelayinseedlingemergence.TheseresultsindicatethatairplasmacanchangethephysiologicalandbiochemicalcharacteristicsofAndrographispaniculataseedsbymodifyingtheseedcoat,combinedwiththeeffectsoftheactiveplasmaspecies,andthatdifferenttreatingdoseshavedifferenteffects.

简介：

简介：Thispaperproposesanewmethodtopredictthecoronaonsetvoltageforarodplaneairgap,basedonthesupportvectormachine(SVM).BecausetheSVMisnotlimitedbythesize,dimensionandnonlinearityofthesamples,thismethodcanrealizeaccuratepredictionwithfewtrainingdata.Onlyelectricfieldfeaturesarechosenastheinput;nogeometricparameterisincluded.Therefore,theexperimentdataofonekindofelectrodecanbeusedtopredictthecoronaonsetvoltagesofotherelectrodeswithdifferentsizes.Withtheexperimentaldataobtainedbyozonedetectiontechnology,andexperimentaldataprovidedbythereference,theefficiencyoftheproposedmethodisvalidated.Accuratepredictedresultswithanaveragerelativelessthan3%areobtainedwithonly6experimentaldata.

简介：Thispaperpresentstheresultsofaluminumsurfacetreatmentbydiffusecoplanarsurfacebarrierdischarge.Thegoalsaretostudytheeffectivenessoftheplasmatreatmentandthedependenceofitsefficiencyonoperationparameters,suchassample-to-electrodedistance,treatmenttimeorgasatmosphere.Threetypesofaluminummaterials(bricks,sheetsandthinfilms)weretestedtoensurethereliabilityofthetreatment.Thechangesinthesurfacepropertieswerecharacterizedbythesurfacefreeenergy,atomicforcemicroscopy,attenuatedtotalreflectanceFouriertransforminfraredspectroscopy(ATRFTIR)andX-rayphotoelectronspec-troscopy(XPS).Theinfluenceofagingeffectonthetreatmentwasalsomeasuredanddiscussed.

简介：Dielectric-barrierdischarges(DBDs)inatmosphericpressureairhavebeenstudiedbyusingapower-frequencyvoltagesource.InthispapertheelectricalcharacteristicsofDBDsus-ingglassandaluminadielectricshavebeeninvestigatedexperimentally.AccordingtotheLissajousfiguresofvoltage-charges,itisdiscoveredthatthedischargepowerforanaluminadielectricismuchhigherthanthatforaglassdielectricatthesameappliedvoltage.Also,thevoltage-currentcurvesoftheglassandaluminadielectricsconfirmthefactthatthedielectricbarriersbehavelikesemiconductingmaterialsatcertainappliedvoltages.

简介：Indouble-pulselaser-inducedbreakdownspectroscopy(DP-LIBS),thecollinearfemtoseconddouble-pulselaserconfigurationisexperimentallyinvestigatedwithdifferentinitialsampletemperaturesusingaTi:sapphirelaser.Theglasssampleisablatedtoproducetheplasmaspectroscopy.Duringtheexperiment,thedetectedspectrallinesincludetwoNa(I)lines(589.0nmand589.6nm)andoneCa(I)lineatthewavelengthof585.7nm.Theemissionlinesaremeasuredatroomtemperature(22°C)andthreehigherinitialsampletemperatures(Ts=100°C,200°C,and250°C).Theinter-pulsedelaytimerangesfrom-250psto250ps.Theinter-pulsedelaytimeandthesampletemperaturestronglyinfluencethespectralintensity,andthespectralintensitycanbesignificantlyenhancedbyincreasingthesampletemperatureandselectingtheoptimizedinter-pulsetime.Forthesameinter-pulsetimeof0ps(single-pulseLIBS),theenhancementratioisapproximately2.5atTs=200°CcomparedwiththatobtainedatTs=22°C.Forthesameinter-pulsetimeof150ps,theenhancementratiocanbeupto4atTs=200°CcomparedwiththatobtainedatTs=22°C.Thecombinedenhancementeffectsofthedifferentinitialsampletemperaturesandthedouble-pulseconfigurationinfemtosecondLIBSaremuchstrongerthanthatofthedifferentinitialsampletemperaturesorthedouble-pulseconfigurationonly.