简介:Themicroscopiceffectivechargesinmirrornuclei51Mnand51Feareinvestigatedwiththeparticle-vibrationcouplingmodelbasedontheself-consistentSkyrme-Hartree-Fockandcontinuumrandom-phase-approximationapproaches.Theisovectorpartsarepredictedtobearound0.15,andtheprotoneffectivechargesarearound1.25e,whichislessthantheempiricalvalueofeeffp=1.5e.Themicroscopiceffectivechargesinneutronrich51Mnareabout10%lessthanitsprotonrichmirror.TheseeffectivechargesarecombinedwiththeshellmodeltocalculatethereducedelectricquadrupoletransitionprobabilityB(E2)valuesin51Mnand51Fe.ItturnsoutthatthemicroscopiceffectivechargeshavewellreproducedtheB(E2)valuesanditsratiointheterminatingstates.
简介:InspiteofthecurrentprevalenceoftheCVD-basedprocesses,theelectricarcremainsaninterestingprocessforthesynthesisofcarbonnanoforms,thankstoitsversatility,robustnessandeasiness.Italsoallowsperformingin-situsubstitutionofcarbonatomsbyhetero-elementsinthegraphenelattice.Ourworkaimstoestablishacorrelationbetweentheplasmaproperties,typeandchemicalcomposition(andthesubstitutionrate)oftheobtainedsingle-wallcarbonnanotubes.TheplasmawascharacterizedbyopticalemissionspectroscopyandtheproductswereanalyzedbyhighresolutiontransmissionelectronmicroscopyandcorelevelElectronEnergy-LossSpectroscopy(EELS).Resultsshowthatahighboroncontentleadstoaplasmatemperaturedecreaseandhinderstheformationofnanotubes.Thiseffectcanbecompensatedbyincreasingthearccurrentand/oryttriumcontent.Theoptimalconditionsforthesynthesisofboron-and/ornitrogen-substitutednanotubescorrespondtoahighaxialplasmatemperatureassociatedtoastrongradialgradient.EELSanalysisconfirmedthattheboronincorporatesintothegraphemelattice.
简介:Characteristicsofiontemperaturemeasuredwithcharge-exchangerecombinationspectroscopy(CXRS)werestudiedinOhmic,lower-hybrid-wave(LHW)drivenandion-cyclotron-resonance-frequency(ICRF)heatedplasmasinHT-7.TheresultsindicatethatthecentraliontemperatureTi0followstheone-thirdpowerlawintheproductofcentralline-averageddensityneandplasmacurrentIpinOhmicdischargesandisthereforeconsistentwiththeArtsimovichscalinglawTi0=K·(Ip·Bt·ne·R2)1/3.ItisshownthatthereisanappreciableincreaseofiontemperatureduringtheoperationwithbothLHWandICRFandthattheincrementofiontemperatureinthoseshotsismainlyduetotheenergytransferviacollisionsbetweenionsandelectronsratherthatbydirectheatingoftheions.
简介:SawtoothcontrolexperimentswereperformedonHT-7withalimiterconfigurationandontheExperimentalAdvancedSuperconductingTokamak(EAST)withadoublenullcon-figuration.Thesawtoothperiodcanbemodifiedbylowerhybridwave(LHW)andioncyclotronresonancefrequency(ICRF).Differentsawtoothbehaviorwasobservedwiththesameplasmadensity,LHWpowerbutdifferentplasmacurrentsonHT-7.TherewasadwelltimebetweenLHWaddedandthesawtoothstabilizationonHT-7whilethesawtoothstabilizationimmediatelyhappenedwhenLHWpowerwasinjectedonEAST.Thepossiblemechanismofthesawtoothcontrolisdiscussedinthispaper.Alltheexperimentalresultshaveprovedthatpowerdepositionoftheradiofrequency(RF)shouldbethekeyfactorforsawtoothcontrol.