简介:Thedefectchangesin6H-SiCafterannealingand10MeVelectronirradiationhavebeenstudiedbyusingavariable-energypositronbeam.Itwasfoundthatafterannealing,thedefectconcentrationinn-type6H-SiCdecreasedduetorecombinationwithinterstitials.Whenthesamplewasannealedat1400℃for30mininvacuum,a20-nmthicknessSilayerwasfoundonthetopoftheSiCsubstrate,thisisadirectproofoftheSiatomsdiffusingtosurfacewhenannealedathightemperaturestages.After10MeVelectronirradiation,forn-type6H-SiC,theSparameterincreasedfrom0.4739to0.4822,andtherelativepositron-trappingratewasabout27.878timesoftheoriginsample,thisshowsthattherearesomedefectscreatedinn-type6H-SiC.Forp-type6H-SiC,itisveryunclear,thismaybebecauseoftheoppositechargeofvacancydefects.
简介:Theoreticalbeamintensitydistributionisderivedfortheneutral-beam-injectionionsourcewithamulti-slotextractioninEAST.Thebeamintensityprofile,bothalongandperpendiculartotheinjectingdirectionandthebeampowerdepositiontotheinnerelementsintheneutralbeaminjector(NBI)areevaluated.Theresultsindicatethatthetransversebeamintensityismuchhigherthanthelongitudinalone.Thisstudycouldprovideinformationforthedesignofvacuumsystem,structureofinnerelementsandcoolingsystemoftheneutralbeaminjectorinEAST.
简介:TooptimizetheoperationparametersofthebeamlineofNBIonHL-2A,featuresofthebeamline,includingthebeamprofileandthepowerdepositedoncomponentsandinjectedintothetokamakplasma,weremeasured.Theoperationalparametersofthefoursourcesonthebeamlinewereoptimizedwiththemonitorofthebeamprofileandbeampower,andthetransmissionefficiencyoftheNBIinjectedpowerwasthereforeincreased.AbeamdiagnosticsystemforthebeamlineoftheNBIsystemonHL-2Aaswellasthediagnosedresultswasalsopresented.
简介:Wereportthefabricationofsubmicrometerpitsarray(SP-array)on6H-SiCsurfacebytheinterferenceoftwofemtosecondlaserbeams.FormationmechanismsandopticalabsorptionofSP-arrayarestudied.Therelativereflectivityandtransmissivityofwhitelightdecreaseto10%ofthevaluesofSiCcrystal,andtheopticalabsorptionisenhancedto97%.Therelativereflectivityandtransmissivityofincidentangleswithintherangeof20°-60°arekeptbelow25%.TheenhancementmechanismofopticalabsorptionoftheSP-arrayisalsodiscussed.
简介:BeamModulatorofPhotoelectricPulse¥GuZhongdao;WangWeiandDongChengfuTheexplorationofnuclidefarfromtileβstabilityline(exotic...
简介:BeamDiagnosticSystemforSFC¥SongHaihongThediagnosticdevicesfortheinjectorSFCinclude3movableradialprobeswith10differentialandin...
简介:Neutralbeaminjection(NBI)isrecognizedasoneofthemosteffectivemeansforplasmaheating.A100slongpulseneutralbeamwith30keVbeamenergy,10Abeamcurrentanda100slongpulsemodulatingneutralbeamwith50keVbeamenergy,16AbeamcurrentwereachievedintheEASTneutralbeaminjectoronthetest-stand.ThepreliminaryresultssuggestthatEAST-NBIsysteminitiallypossesstheabilityoflongpulsebeamextraction.
简介:RadioactiveIonBeamLineinLanzhou¥ZhanWenlong;GuoZhongyan;LiuGuanhua;YinQuanmin;ZhouJianqunandWangYifangAsanewfrontierinnu...
简介:Thedynamicresponseofthenon-linearelasticsimplysupportedbeamsubjectedtoaxialforcesandtransverseperiodicloadisstudied.Melnikovmethodisusedtoconsiderthedynamicbehav-iorofthesystemwhosepost-bucklingpathissteady.Theeffectofthehigherordertermsinthecon-trollingequationistakenintoaccount.Itisfoundthatthefifth-ordertermshaveagreatinfluenceonthedynamicbehaviorofthesystem.Theresultshowsthatthereexisteitherhomoclinicorbitsorhete-roclinicorbitsinthesystem.Inthispaper,thecriticalvaluesofthesystementeringchaoticstatesaregiven.Thediagramofanexampleisshown.
简介:Wededuceacompletewavepropagationequationthatincludesinhomogeneityofthedielectricconstantandpresentthispropagationequationincompactvectorform.Althoughsimilarequationsareknowninnarrowfieldssuchasradiowavepropagationintheionosphereandelectromagneticandacousticwavepropagationinstratifiedmedia,wedevelophereanovelapproachofusingsuchequationsinthemodelingoflaserbeampropagationinnonlinearmedia.Ourapproachsatisfiesthecorrespondenceprinciplesinceinthelimitofzero-lengthwavelengthitreducesfromphysicaltogeometricaloptics.
简介:Inthispaper,theboundarystabiligstionoftbeTimoshenkoequationofanononiformbeam,withclarrmpedboundaryconditionatoneendandwitbbendingmomentandshearforcecontrolsattheotherend,isconsidered.Itisprovedthatthesystemisexponentiallystahilizablewhenthebendingmomentandshearforcecontrolsaresimultaneouslyappiied.Thefrequencydomainmethodandthemultipliertechniqueareused.
简介:Thedynamicresponseofastrain-softeningbeamsubjectedtoatransverseimpulsiveonitstipisinvestigated.Asofteningmoment-curvaturerelationisassumedforthebeamandaclosedformsolutionisobtainedforaspecialkindofload,whichshowsthatthereexistsasofteningregioninthebeamandthisre-gionpropagatesalongthebeam.Thisresultindicatesthat,exceptforthepossiblediscretesofteningpointswithrotationdiscontinuitycausedbythedeformationlocalization,theexistenceofthesofteningregionanditstravellingalongthebeamaretheessentialfeaturesofthedynamicresponseofastrain-softeningbeam.Theresultsalsoshowthatthefailureofthebeamshouldtakeplaceunderaspecialloadandthecriticalconditiononwhichthedynamicfailureoccursisgiven.
简介:Thequasi-conformingelementofthecurvedbeamandshallowcurvedbeamisgiveninthispaper.Numericalexamplesillustratethatthequasi-conformingelementsofthecurvedbeamandshallowcurvedbeamWhichisusedtoaooroximatethecurvedbeamhavebetteraccuracythanthestraightbeamelement.Thecurvedbeamelementconstructedbydisplacementmethodcannotsatislyrigidbodymotionconditionandthevervfinegridshavetobeusedinordertosatisfyrigidbodymotionconditionapproximately.Inthispaperitisprovedthatthestraightbeamelementandthequasi-conformingelementofthecurvedbeamandshallowcurvedbeam.whenelementsizeisreducedinfinitely,haveconvergenceratewiththesameorderO(l~2)andwhenregulurelementsareused,Iistheelementlength.