简介:Wetrytoapplyaconstituentquarkmodel(avarietychiralconstituentquarkmodel)andtheresonatinggroupapproachforthemulti-quarkproblemstocomputetheeffectivepotentialbetweentheNN-inS-wave(thequarksinthenucleonsNandN-,andthetwonucleonsrelativelyaswell,areinSwave)soastoseethepossibilityiftheremaybeatightboundstateofsixquarksasindicatedbyastrongenhancementatthresholdofpp-inJ/ψandBdecays.TheeffectivepotentialwhichweobtainintermsofthemodelandapproachshowsiftheexperimentalenhancementisreallycausedbyatightS-waveboundstateofsixquarks,thenthequantumnumberoftheboundstateisverylikelytobeI=1,JPC=0-+.
简介:Weinvestigatetheareadistributionofclusters(loops)inthehoneycombO(n)loopmodelbymeansofthewormalgorithmwithn=0.5,1,1.5,and2.Atthecriticalpoint,thenumberofclusters,whoseenclosedareaisgreaterthanA,isproportionaltoA-1withaproportionalityconstantC.WeconfirmnumericallythatCisuniversal,anditsvalueagreeswellwiththepredictionsbasedontheCoulombgasmethod.
简介:ThepresolarSiCgrains[1]carrytheoriginalstellarnucleosynthesissignature.Theirisotopicanomaliescomparedtothesunarethestrongconstrainsinthesupernovae(SN)modelcalculations.The15N-excessinsomeSiC-ABgrains(12C/13C<10and14N/15N<272)isoneofthechallengesofcore-collapsesupernovae(CCSNe)models[2].Recently,PignataripointedoutthattheentrainmentofH-richmaterialintotheHeshellbeforetheSNexplosionallowsthecoproductionof13C,15Nand26Al,whichprovidesanewproductionscenarioforSiC-ABgrains[2].IntheHeshellnucleosynthesis,the13Cisproducedthrough12C(p,γ)13N(β+γ)13Creaction.The14Nissynthesizedthrough13N(n,γ)and13C(p,γ)reactions.
简介:Low-energypartial-waveπNscatteringdataisreexaminedwiththehelpoftheproductionrepresentationofpartial-waveSmatrix,wherebranchcutsandpolesarethoroughlyunderconsideration.Theleft-handcutcontributiontothephaseshiftisdetermined,withcontrolledsystematicerrorestimates,byusingtheresultsofO(p^3)chiralperturbativeamplitudesobtainedintheextended-onmass-shellscheme.InSnandPuchannels,severediscrepanciesareobservedbetweenthephaseshiftdataandthesumofallknowncontributions.Statisticallysatisfactoryfitstothedatacanonlybeachievedbyaddingextrapolesinthetwochannels.WefindthataSnresonancepolelocatesat√zr=(0.895±0.081)—(0.164±0.023)iGeV,onthecomplexs-plane.Ontheotherhand,aFnvirtualpole,asanaccompanyingpartnerofthenucleonbound-statepole,locatesat√zv=(0.966±0.018)GeV,slightlyabovethenucleonpoleontherealaxisbelowthreshold.Physicaloriginofthetwonewlyestablishedpolesisexploredtothebestofoiirknowledge.ItisemphasizedthattheO(p^3)calculationgreatlyimprovesthefitqualitycomparingwiththepreviousO(p^2)one.
简介:Anenvironmentallyfriendlyprecursor,adenosine,hasbeenusedasadualsourceofCandNtosynthesizenitrogen-dopedcarboncatalystwith/withoutFe.Ahydrothermalcarbonizationmethodhasbeenusedandwateristhecarbonizationmedia.Themorphologyofsampleswith/withoutFecomponenthasbeencomparedbyHRTEM,andtheresultshowsthatFecanpromotethegraphitizationofcarbon.Furtherelectro-chemicaltestshowsthattheoxygenreductionreaction(ORR)catalyticactivityofFe-containingsample(C–FeN)ismuchhigherthanthatoftheFe-freesample(C–N).Additionally,theintermediatesofC–FeNformedduringeachsyntheticprocedurehavebeenthoroughlycharacterizedbymultiplemethods,andthefunctionofeachprocedurehasbeendiscussed.TheC–FeNsampleexhibitshighelectro-catalyticstabilityandsuperiorelectro-catalyticactivitytowardORRinalkalinemedia,withitshalf-wavepotential20mVlowerthanthatofcommercialPt/C(40wt%).Itisfurtherincorporatedintoalkalinepolymerelectrolytefuelcell(APEFC)asthecathodematerialandledtoapowerdensityof100mW/cm~2.
简介:ThecapacitytocaptureCO2wasdeterminedinseveralstoichiometriccompositionsintheLi2O–Bi2O3system.Thecompounds(Li7BiO6,Li5BiO5,Li3BiO4andLiBiO2phases)weresynthesizedviasolid-statereactionandcharacterizedbyX-raydiffraction,scanningelectronmicroscopyandN2adsorptiontechniques.Thesampleswereheat-treatedattemperaturesfrom40to750°CundertheCO2atmospheretoevaluatethecarbonateformation,whichisindicativeofthecapacityofCO2capture.Moreover,Li7BiO6showsanexcellentCO2capturecapacityof7.1mmol/g,whichisconsiderablyhigherthanthoseofotherpreviouslyreportedceramics.Li7BiO6isabletoreactwithCO2from240°Ctoapproximately660°CshowingahighkineticreactionevenatCO2partialpressurevaluesaslowas0.05.
简介:方案1:“窝里K”成本:一部CD机,一副嗓子总需经费:CD机+唱片卡担是条狗,当钱包开始瘪的时候,我们开始强烈赞同冯大导演这句话。个人演唱会不是明星的专利啊,
简介:ThenucleiaroundmagicnumberN=126areinvestigatedinthedeformedrelativisticmeanfield(RMF)modelwitheffectiveinteractionsTMA.WefocusinvestigationsontheN=126isotonicchain.TheN=126shellevolutionisstudiedbyanalyzingthevariationsoftwo-neutron(proton)separationenergies,quadrupledeformations,singleparticlelevelsetc.Thegoodagreementoftwo-neutronseparationenergiesbetweenexperimentaldataandcalculatedvaluesisreached.TheRMFtheorypredictsthatthesizesofN=126shellbecomesmallerandsmallerwiththeincreasingofprotonnumberZ.However,theN=126shellexistsinourcalculatedregionallalong.Accordingtothecalculatedtwo-protonseparationenergies,theRMFtheorysuggests~(220)Puisatwo-protondrip-linenucleusintheN=126isotonicchain.
简介:ThecorrelationbetweenphasestructuresandsurfaceacidityofAl2O3supportscalcinedatdifferenttemperaturesandthecatalyticperformanceofNi/Al2O3catalystsintheproductionofsyntheticnaturalgas(SNG)viaCOmethanationwassystematicallyinvestigated.Aseriesof10wt%NiO/Al2O3catalystswerepreparedbytheconventionalimpregnationmethod,andthephasestructuresandsurfaceacidityofAl2O3supportswereadjustedbycalciningthecommercialγ-Al2O3atdifferenttemperatures(600–1200C).COmethanationreactionwascarriedoutinthetemperaturerangeof300–600Catdifferentweighthourlyspacevelocities(WHSV=30000and120000mL·g-1h-1)andpressures(0.1and3.0MPa).ItwasfoundthathighcalcinationtemperaturenotonlyledtothegrowthinNiparticlesize,butalsoweakenedtheinteractionbetweenNinanoparticlesandAl2O3supportsduetotherapiddecreaseofthespecificsurfaceareaandacidityofAl2O3supports.Interestingly,NicatalystssupportedonAl2O3calcinedat1200C(Ni/Al2O3-1200)exhibitedthebestcatalyticactivityforCOmethanationunderdifferentreactionconditions.LifetimereactiontestsalsoindicatedthatNi/Al2O3-1200wasthemostactiveandstablecatalystcomparedwiththeotherthreecatalysts,whosesupportswerecalcinedatlowertemperatures(600,800and1000C).ThesefindingswouldthereforebehelpfultodevelopNi/Al2O3methanationcatalystforSNGproduction.
简介:A60%Fe/Al2O3catalystwaspreparedbytheco-precipitationmethod.ItwasreducedbyH2toproducemetallicFe,whichwasthensulfidedbyCS2toFe0.96SandFe3S4orphosphidedbytriphenylphosphine(PPh3)inliquidphasestoFe2PandFeP.Itwasfoundthattheironsulfides(Fe0.96SandFe3S4)exhibitedthelowactivityforthehydrodesulfurization(HDS)reactions.TheHDSactivitywasalsolowontheFe(metal)/Al2O3andFe2P/Al2O3catalystssincetheywereconvertedintoFe0.96SandFe3S4duringtheHDSreactions.Incontrast,theFeP/Al2O3wasfoundtobestableandactivefortheHDSreactions.Inparticular,FeP/Al2O3possessedsignificantlysmallerFePparticlesthanFeP/C,leadingtothesignificanthigherHDSactivityofFeP/Al2O3thanFeP/C.