简介:Theβ-decaysofneutron-richcarbon,nitrogenandfluorineisotopeshavebeensys-tematicallystudiedusingtheOXBASHshellModel.Inthepsd,spsdandspsdpfmodelspace,weusetheWBPinteractiontocalculatethehalf-livesandneutronemissionprobabilitiesofneutron-richcarbonandnitrogenisotopes,respectively.WiththeUSD(W)andCWinteractions,wecalculatethehalf-livesandneutronemissionprobabilitiesofneutron-richfluorineisotopeinthesdmodelspace,respectively.Thecalculatedhalf-livesandneutronemissionprobabilitiesrepro-ducerecentexperimentaldataverywell.Itseemstoshowthattheparticlesoftheneutron-richcarbonandnitrogenisotopesaremainlyexcitedinthespsdspace.Theβ-decayof21Ntotheneutronboundstatesin21Oismostlythefirstforbiddentransitionwhichmakestheneutronemissionprobabilityincrease.Thetheoreticalcalculationofβ-decayof25Fto25NewithCWinteractionshowsthatCWinteractionisbetterthanUSDinteraction.
简介:Plasmasourceperformanceparameters,includingplasmaejectiondensityandvelocity,greatlyaffecttheoperationofashort-conduction-timeplasmaopeningswitch(POS).Inthispaper,theplasmasourceusedinthePOSofQiangguangIgeneratorischosenasthestudyobject.AtfirstthePOSworkingprocessisanalyzed.TheresultshowsthattheopeningperformanceofthePOScanbeimprovedbyincreasingtheplasmaejectionvelocityanddecreasingtheplasmadensity.Theinfluenceofthecableplasmagunstructureandnumberontheplasmaejectionparametersisexperimentallyinvestigatedwithtwochargecollectors.Finallyasemi-empiricalmodelisproposedtodescribetheexperimentalphenomenon.
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:Ananalyticalstudyispresentedonthemodaldispersioncharacteristics,groupvelocity,andeffectivegroup,aswellasthephaseindexofaternaryonedimensionalplasmaphotoniccrystalforanobliquelyincidentelectromagneticwaveconsideringtheeffectofcollisionsinplasmalayers.Thedispersionrelationisderivedbyusingthetransfermatrixmethodandtheboundaryconditionsbasedonelectromagnetictheory.Thedispersioncurvesareplottedforboththenormalphotonicbandgapstructureandtheabsorptionphotonicbandgapstructure.Itisfoundthattheincreaseintheangleofincidenceshiftsthephotonicbandgaptowardhigherfrequencies.Also,thecutofffrequencyisindependentofcollisions.
简介:Inthepaper,relativisticfilamentationofintenselaserbeamininhomogeneousplasmaisinvestigatedbasedonthenonparaxialregiontheory.Theresultsshowthat,relativisticnonlinearityplaysamainroleinbeamfilamentation,andplasmainhomogeneityfurtherreinforcesthebeamfilamentation.Thecombinationeffectsofrelativisticnonlinearityandplasmainhomogeneitycangenerateparticularlyintenseandshortpulselaser.However,plasmainhomogeneityleadstoobviousfilamentationinstability.
简介:AwaterplasmawasgeneratedbyDCarcdischargewithahafniumembeddedrodtypecathodeandanozzle-typeanode.Thedischargecharacteristicswereexaminedbychangingtheoperationparameterofthearccurrent.Thedynamicbehaviorofthearcdischargeledtosignificantfluctuationsinthearcvoltageanditsfrequency.Analysesofthehighspeedimageandthearcvoltagewaveformshowedthatthearcdischargewasintherestrikemodeanditsfrequencyvariedwithinseveraltensofkilohertzaccordingtotheoperatingconditions.Thelargerthermalplasmavolumewasgeneratedbythehigherflowfromtheformingsteamwithahigherrestrikefrequencyinthehigherarccurrentconditions.Inaddition,thecharacteristicsofthewaterplasmajetwereinvestigatedbymeansofopticalemissionspectroscopytoidentifytheabundantradicalsrequiredinanefficientwastetreatmentprocess.
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:Basedonthefundamentalideasconcerningmicrowaveattenuationinplasma,weobtainanewexpressionoftransmissionattenuationofmicrowavesasafunctionoftheincidentwavefrequency.Andwithreasonablehypothesis,analyticalformsoftheelectrondensityandtheelectron-neutralcollisionfrequencyarederivedfromtheequationsofthetransmissionattenuationofmicrowavesattwonearfrequencies.Thismethodgivesaneffectiveandeasyapproachtodiagnosetheunmagnetizedplasma.
简介:AmedicalcastCoCrMoalloywascoatedbyplasmanitridingprocesstoenhancethewearresistance.Themicrostructures,phasesandmicro-hardnessofnitridedlayerswereinvestigatedbyatomicforcemicroscopy(AFM),scanningelectronmicroscopy(SEM),X-raydiffraction(XRD)andmicro-hardness.Tribologicalpropertieswereinvestigatedonapin-on-discweartesterunder25%bovineserumsolutions.Theexperimentalresultsshowedthatplasmanitridingwasapromisingprocesstoproducethick,hardandwearresistantlayersonthesurfaceofCoCrMoalloy.TheharderCrNandCr2Nphasesformedontheplasmanitridedlayerwiththecompactnano-crystallinestructure.Comparedwiththeuntreatedsample,allnitridedsamplesshowedthelowerwearratesandhigherwearresistanceatdifferentappliedloadsandnitridingtemperatures.Itwasconcludedthattheimprovementofwearresistancecouldbeascribedtotheformationofthickerandhardernitridedlayerswiththespecificmicrostructuresonnitridedsurfaces.
简介:Theglidingarccanofferhighenergyefficiencyandselectivityforchemicalreactionsandhasbeenwidelyappliedinmaterialprocessing,environmentalprotectionandotherindustrialareas.Butthedischargeproperties,measurementofplasmaparametersandrelatedphysicalpro-cessesoftheglidingarcdischargestillneedtofurtherstudied.Inthisstudy,theglidingarcwasdrivenbythetransversemagneticfieldtoproducethenon-equilibriumplasmaathighpressure.Theparametersoftheplasmaatourobservedpointweremeasuredbyopticalmethods.Theexperimentalresultshowsthattheelectrontemperatureisabout0.6eVandtheheavyparticletemperatureisapproximately2987±250K.
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:Inourpreviouswork,aplasmaapproachforsingleattosecondpulse(AP)generationwasproposed.Afew-cyclerelativisticcircularlypolarizedlaserpulsewillinduceasingledrasticoscillationofplasmaboundary,fromwhichhigh-orderharmonicsandfurthermoreanultra-intensesingleAPcanbegeneratednaturallyafteritisreflected.Analyticalmodelandsimulationsbothdemonstratethattheprocessismostlyefficientasthepulsedurationisclosetotheplasmarespondingtime.Theeffectsofplasmadensityrampareanalyzedhere,suggestingthattheproposalisstillquiteefficientwithappropriatedensitygradientintheramp.Atlast,acombinedapproachisemployedtoobtainsingleAPwith30fsincidentlaser.Therelativelylarge-durationpulseisfirstlyshortenedbyadensitydroppingthinfoil,andthenreflectedfromanoverdenseplasmatarget.One-dimensionalsimulationshowsthata600assinglelightpulseisgeneratedwithpeakintensityof3×1020W/cm2.
简介:Waterisanimportantcomponentinplantcellswithplantaquaporinbeingthemajorproteinforwatertransportinandbetweenplantcells.Asasubfamilyofplantaquaporins,theplasmamembraneintrinsicproteins(PIPs)locatedintheplasmamembraneareclassic,highwater,selectivechannelproteins.ThispaperfocusesonrecentadvancesinthemolecularbiologyofPIPsconcerningstructuralcharacteristics,biologicalfunction,andaregulationmechanism.PIPspossesstwohighlyconserveddomains:GGGANXXXXGYandTGI/TNPARSL/FGAAI/VI/VFWF/YN.PIPscanalsobedividedintotwophylogeneticsubgroupsnamedPIP1andPIP2.PIP1possesseslongerNterminalsequencesandshorterCterminalsequencesthanPIP2withconservedaminoacidsequencesrespectively.StudiesoftransgenicplantsandexpressioninXenopusoocytescellsindicatethatPIPsnotonlymayfacilitatetransportofwaterandsmallneutralsoluteslikeCO2andglycerin,buttheyalsopossessmanyphysiologicalfunctions.Thefunctionsofplantaquaporinsareregulatedbymanyfactorsincludingpost-translationalmodification,heteromerization,pHvalue,anddivalentcations.TheseresultsindicatedthatPIPsactasapivotalroleinwaterandsmallneutralsolutestransportinplants.
简介:Intheplasmasheathanarrowplasmachannelgeneratedbyultraintenselaserpulsesissimplifiedasaspecialcylindricalandhollowplasmawaveguidewiththeinfinitethicknessoftheplasmacladding.Theelectromagneticwave(EM)propagationpropertiesoftheplasmachannelnearthecutoffandfarfromthecutoffareconsidered.TheoreticalanalysisshowsthatTE0mandTM0mandhybridmodesemergeintheplasmachannel,whichisinfluencedbythenormalizedfrequencyparameterBandnumericalapertureNA.Thecutoffsofthevariousmodesareapproximated.Single-modeoperationispossiblewithoutahigh-frequencylimitationinthechannel.
简介:导致激光的血浆今天代表普遍分光镜的排放来源。它能容易用紧缩、可靠的毫微秒被产生材料的一个大变化上的搏动的激光。它为例如有导致激光的故障光谱学(解放)的spectrochemical分析的申请变得那么流行一个人趋于忘记导致它的产生并且管理它的进化的复杂物理、化学的过程。这篇评论文章的目的是总结必要的背景从它的产生理解并且描述导致激光的血浆到它的扩大进周围的气体。目的是不详细说明每个过程的细节;在文学为那有众多的专业化论文和书。这里的目标是在必要理解元素需要从一个复杂过程把导致激光的血浆描述为结果的一份一样的报纸聚在一起。这些元素能在背景气体在象激光事相互作用,材料的激光脱离,热、电离的气体的光、热力学的性质,或血浆繁殖那样的几块相关却独立的地里被驱散。我们相信那介绍以一条全面的路并且在这份报纸的有限的页理解导致激光的血浆的元素的整体将对进一步的开发有用并且优化LIBS技术的使用。每次如此的说明变得可能、有用,在我们的实验室获得的试验性的结果被用来说明学习物理过程。
简介:Azero-dimensionalmodelwhichincludes56speciesofreactantsand427reactionsisusedtostudythebehaviorofchargedparticlesinatmosphericplasmaswithdifferentionizationdegreesatlowaltitude(near0km).TheconstantcoefficientnonlinearequationsaresolvedbyusingtheQuasi-steady-stateapproximationmethod.Theelectronlifetimesareobtainedforafterglowplasmawithdifferentinitialvalues,andthetemporalevolutionsofthemainchargedspeciesarepresented,whicharedominantinreactionprocesses.Theresultsshowthattheelectronnumberdensitydecaysquickly.Thelifetimesofelectronsareshortenedbyabouttwoorderswithincreasingionizationdegree.Electronsthenattachtoneutralparticlesandproducenegativeions.Whentheinitialelectrondensitiesareintherangeof1010~1014cm3,thenegativeionshavesufficientlyhighdensitiesandlonglifetimesforairpurification,disinfectionandsterilization.Electrons,O2,O4,CO4andCO3arethedominantnegativespecieswhentheinitialelectrondensityne0≤1013cm3,andonlyelectronsandCO3areleftwhenne0≥1015cm3.N+2,N+4andO+2aredominantinthepositivechargesforanyionizationdegree.Otherpositivespecies,suchasO+4,N+3,NO+,NO+2,Ar+2andH3O+·H2O,aredominantonlyforacertainionizationdegreeandinacertainperiod.
简介:Atypeofelectricaldischargecalledslidingdischargewasdevelopedtogenerateplasmaaerodynamicactuationforflowcontrol.Athree-electrodeplasmasheetactuatordrivenbyrepetitivenanosecondpulseswithanegativeDCcomponentwasusedtogenerateslidingdischarge,whichcanbecallednanosecond-pulseslidingdischarge.Thephenomenologyandbehaviouroftheplasmasheetactuatorwereinvestigatedexperimentally.Dischargemorphologyshowsthattheformationofnanosecond-pulseslidingdischargeisdependentonthepeakvalueoftherepetitivenanosecondpulsesandnegativeDCcomponentappliedontheplasmasheetactuator.Comparedtodielectricbarrierdischarge(DBD),theextensionofplasmainnanosecond-pulseslidingdischargeisquasi-diffusive,stable,longerandmoreintensive.TestresultsofparticleimagevelocimetrydemonstratethatthenegativeDCcomponentappliedtoathirdelectrodecouldsignificantlymodifythetopologyoftheflowinducedbynanosecond-pulseDBD.Bodyforceinducedbythenanosecond-pulseslidingdischargecanbeapproximatelyintheorderofmN.BoththemaximumvelocityandthebodyforceinducedbyslidingdischargeincreasesignificantlyascomparedtosingleDBD.Therefore,nanosecond-pulseslidingdischargeisapreferableplasmaaerodynamicactuationgenerationmode,whichisverypromisinginthefieldofaerodynamics.