简介:Asimple,lowcost,easilymaintained,andreliablefielddistortionsparkgaphasbeendevelopedtooperateatavoltageupto30kV.Theheaderconstructionnecessarytoattachthesparkgapswitchtoasingle12.5μF,40kV(10kJ)capacitorisdescribed.Themainfeaturesofthesparkgapareitswiderangeofvoltageoperation,highcurrentcapacity,lowinductanceandlonglifetime.Theperformanceofsparkgaphasbeentestedinaplasmafocusandresultsarepresentedinthisreport.
简介:Thispaperpresentsanalysesofionflowcharacteristicsandiondischargepulsesinasphere-groundplateelectrodesystem.Asaresultofvariationinelectricfieldintensityintheelectrodegap,theionflowstowardselectrodesgeneratenon-uniformdischargingpulses.Inspectionofthesepulsesprovidesusefulinformationonionicstreamkinetics,theeffectivethicknessofioncoveraroundelectrodes,andthetimingofioncloudsdischargepulsesequences.Afinitedifferencetimedomain(FDTD)basedspace-chargemotionsimulationisusedforthenumericalanalysisofthespatio-temporaldevelopmentofionicflowsfollowingthefirstTownsendavalanche,andthesimulationresultsdemonstrateexpansionofthepositiveionflowandcompressionofthenegativeionflow,whichresultsinnon-uniformdischargepulsecharacteristics.
简介:Inageneralplane-parallelelectrodesystem,theedgeoftheelectrodewillunderminetheuniformityofthedielectricbarrierdischarge(DBD)becauseoftheinfluenceofthedistortedelectricalfield.Inthispaper,theinfluenceofthenon-uniformelectricalfieldontheedgeefectofDBDsinashort-gapisinvestigated.WepresentsomeoftheexperimentalresultsofDBDsproducedbythreekindsofconvex-sphericalelectrodes.Theresultsshowthatthereisadarkarea(thehomogeneousdischarge)inthecentralregionoftheelectrodeandabrighthalo(thefilamentarydischarge)intheouterperipheralregion,andtheradiusofthedarkregionisdeterminedbytheelectrodegeometry.Thecalculatedresultsofthetransverse(radial)fieldcomponentdistributiononthesurfaceoftheelectrodesshowthattheedgeefectdoesnotcomefromtheelectrodeedge,butthetransversefield.Thedischargehasenoughspacetobefullydevelopedandthenformatthefilamentarydischargeintheouterperipheralregionbecausethestreamerofthefilamentarydischargeisdriventomovealongthedirectionofthelongerpathbythetransversefield.Thus,thehomogeneousdischarge(theTownsendDBDoraglowDBD)couldnotbeproducedinthisarea.
简介:Breakdowncharacteristicsofagapbreakdownloadwasinvestigatedinthispaper,andareverselyswitcheddynistor(RSD)dischargecircuitwasdesignedbasedontheload.Basedonthecharacteristicsoftheload,theRSDdischargecircuitwasimprovedandoptimized.Thevolumeofthemagneticswitchwasreduced.ToprotectthethyristorandRSD,adiodewasantiparallelyconnectedwiththethyristor,whichreducedthetimerequirementwhenapowervoltagewasappliedtoRSD.Experimentalresultsshowthecircuitdesignedinthispapercanswitchahighvoltageandhighcurrentsmoothly,andallowsthepowervoltagetochangeinawiderrange.
简介:Amorphoussilicon(a-Si),nanocrystallinesilicon(nc-Si)andhydrogenatednanocrys-tallinesilicon(nc-Si:H)filmswerefabricatedbyusingchemicalvapordeposition(CVD)system.Thea-Siandnc-Sithinfilmswereirradiatedwith94MeVXe-ionsatfluencesof1.0×1011ions/cm-2,1.0×1012ions/cm-2and1.0×1013ions/cm-2atroomtemperature(RT).Thenc-Si:Hfilmswereirradiatedwith9MeVXe-ionsat1.0×1012Xe/cm-2,1.0×1013Xe/cm-2and1.0×1014Xe/cm-2atRT.Forcomparison,mono-crystallinesilicon(c-Si)sampleswerealsoirradiatedatRTwith94MeVXe-ions.AllsampleswereanalyzedbyusinganUV/VIS/NIRspectrometerandanX-raypowderdiffractometer.Variationsoftheopticalband-gap(Eg)andgrainsize(D)versustheirradiationfluencewereinvestigatedsystematically.Theobtainedresultsshowedthattheopticalband-gapsandgrainsizeofthethinfilmschangeddramaticallywhereasnoobservablechangewasfoundinc-SisamplesafterXe-ionirradiation.Possiblemechanismunderlyingthemodificationofsiliconthinfilmswasbrieflydiscussed.