学科分类
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26 个结果
  • 简介:Thereisagrowingsupportforthelowlyingscalarmesonsf0(500),f0(980),a0(980),and(800)tobegenerateddynamicallyfromtheinteractionofpseudoscalarmesons,whilethecaseofthenextsetofscalarresonancesathigherenergies,f0(1370),f0(1710),K0(1430)ismoreaquestionofdebate.Soisthecaseofthetensorresonancesf2(1270),f′2(1525),K2(1430).AnewperspectiveonthesestateshasbeenofferedinRef.[1]wherethef0(1370)andf2(1270)resonancesareshowntobegeneratedfromtheinteractionprovidedbythelocalhiddengaugeLagrangiansimplementingunitarization.Itisshownthattheideaofthenatureofthesestatesasvectormeson-vectormesoncompositestateshasbeentestedinmanyreactions.Yet,thepermanentdiscussionoftheissuedemandsextrachecksforotherobservablesand,inthissense,theweakdecaysbringanewsourceofvaluableinformationthatshouldservetotestdifferentmodels.

  • 标签: J/Ψ source case SENSE NEXT IDEA
  • 简介:In2010,theBESCollaboration[1]foundaclearenhancementintheK0K0massdistributionintheJ=ψ!ηK0K0decay.SuchanenhancementisusuallyasignatureofanL=0resonancearoundthreshold,whichinthiscasewouldcorrespondstoanh1statewithquantumnumbersIG(JPC)=0??(1+??).Thish1statewaspredictedbytheChiralUnitarytheoryintheKKinteraction.Becauseoftheconversationlaw,thisstatecanonlydecaytoK0K0channel,andcanbestudiedefficientlyintheJ=ψ!ηK0K0decay.

  • 标签: SIGNATURE SIGNATURE QUANTUM CLEAR can BES
  • 简介:ThespectrumoftheΣ(1193)excitedstates,Σ,withisospinI=1andstrangenessS=??1isoneofthemostimportantissuesinhadronicphysics.TheΣresonancesaremostlyproducedandstudiedinK-inducedreactions.ManyΣresonancesarenowcatalogedbytheParticleDataGroup[1].However,ourknowledgeoftheseresonancesisstillverypoor.Intheenergyregionbelow2GeV,onlyafewofthemarewellestablished,suchastheΣ(1385)ofspin-parityJP=3=2+,Σ(1670)ofJp=3=2??andΣ(1775)ofJp=5=2??.Theothersarenotwellestablishedandsomeofthemareevenoflargeuncertaintiesontheirexistence.Thus,thestudyoftheΣresonancewiththeavailableexperimentaldataisnecessary.

  • 标签: EXPERIMENTAL Π now OUR is
  • 简介:Zr1-xTixCo(x=0,0.1,0.2,0.3)alloyswerepreparedbyarc-meltingmethodandtheeffectofTisubstitutiononhydrogenstoragepropertieswasstudiedsystematically.Hydrogendesorptionpressure-composition-temperature(PCT)measurementswerecarriedoutusingSievert’stypevolumetricapparatusforZrCo(at473K,573Kand673K)andZr1-xTixCoalloys(at673K),respectively.ProductsafterdehydrogenationwerecharacterizedbyX-raydiffraction(XRD).Inaddition,thekineticsofZr1-xTixCohydridewasinvestigatedat473Kand673K,respectively,underhydrogenpressureof5MPa.ResultsshowedthatTisubstitutionforZrdidnotchangethecrystalstructureofZrCophase.Withtheincreaseoftemperaturefrom473Kto673K,theextentofdisproportionationforZrCoalloyincreased.WithTicontentincreasingat673K,thedesorptionequilibriumpressureofZr1-xTixCo-H2systemselevatedandthedisproportionationreactionofZr1-xTixCoalloyswasinhibitedeffectively.TisubstitutiondecreasedthekineticsrateandtheeffectivehydrogenstoragecapacityofZr1-xTixCoalloysslightly.Generallyspeaking,itwasfoundthatZr0.8Ti0.2Coalloyhadbetteranti-disproportionationpropertywithlessdecreaseofeffectivehydrogenstoragecapacitywhichwasbeneficialtotritiumapplicationintheInternationalThermonuclearExperimentalReactor(ITER).

  • 标签: ZrCo-based ALLOYS TI substitution hydrogen storage
  • 简介:Thedeuteronisalooselyboundstateoftwonucleons.Itisnaturaltoexpectotherboundstatescomposedoftwohadrons,thatis,hadronicmolecularstates[1].AftertheobservationbytheBelleCollaboration,theX(3872)wasrelatedtoalooselyboundstateofDˉDimmediatelyduetothefactthatitsmassisneartheDˉDthreshold.Recently,theBelleCollaborationannouncedtwochargedbottomonium-likestructuresZb(10610)andZb(10650)neartheBˉBandBˉBthresholds[2].TheanalysisoftheangulardistributionindicatedbothZb(10610)andZb(10650)favorIG(JP)=1+(1+).AstructureZc(3900)closetotheDˉDthresholdwasalsoobservedbytheBESIIIcollaborationinthedecayofY(4260),Y(4260)!+??J=[3].

  • 标签: Bethe-salpter EQUATION APPROACH
  • 简介:DarkMatterParticleExplorer(DAMPE)isapowerfulspacetelescopeforhighenergycosmicraysdetectionsuchas-ray,electronandheavyions.ThemainmotivationofDAMPEistofindtheevidenceofdarkmatterexistence,andthesatelliteisscheduledforlaunchingbeforetheendof2015.ThePlasticScintillatorDetector(PSD),whichisoneofthekeycomponentsoftheDAMPEsystem,hastwomajorfunctionalities:distinguishphotonsfromchargedparticlesbyanti-coincidenceandmeasurethechargeofheavyions.ThePSDisdesignedandfabricatedbytheinstituteofmodernphysics,CAS.Itconsistsof82plasticscintillatorstrips,eachofwhichisreadoutbyPMTatbothends,andadouble-dynodereadoutschemeforPMTisutilizedinordertocoverthelargedynamicrange(fromHtoCa).

  • 标签: BEAM TEST PSD
  • 简介:采用燃烧法合成了La1.6(MoO_4)_3:Eu_0.4^3+纳米晶末,研究了其声子一掺杂-晶格相互作用和发光性质。x射线粉末衍射(XRD)分析表明,在500~900℃退火后,La1.6(MoO_4)_3:Eu_0.4^3+样品为单一晶相。对样品进行了光致发光(PL)测量,激发Mo^6+-O^2-电荷迁移带,观察到Eu^3+的系列发光,表明Mo^6+-O^2-带和Eu^3+间存在能量传递,中心波长分别在λ1=469nm和λ2=426nm处的两个one-phonon边带,相应的声子能量分别为767和1202cm^-1,分别对应于Mo=0和Mo-0-Mo伸缩振动。同时,计算了两个局域模电子一声子耦合强度的黄昆因子分别为S1=0.055和S2=0.037,为揭示其三价离子高传导特性及其负热膨胀物理特性提供了实验基础。

  • 标签: 发光特性 燃烧法 La1.6(MoO_4)_3:Eu_0.4^3+纳米晶 局域模 one-phonon边带
  • 简介:AseriesofZSM-5zeolites,withthemorphologiesofsphere,spherewithcubicparticlesonthesurface,andcubicparticles,weresynthesizedbyhydrothermalmethodusingn-butylamineasthetemplate,assistedbytheadditionofNaClandcrystalseed.X-raydiffraction(XRD),scanningelectronmicroscope(SEM),X-rayfluorescence(XRF)andtemperature-programmeddesorptionofammonia(NH3-TPD)wereusedtocharacterizethesesamples.Thesamplesweretestedwithtoluenemethylationreaction.Themodifiedsamplecomposedofsphericalparticleswith3μmcrystalparticlesonthesurfacehadapara-xyleneselectivityof95%andmaintained79%oftheinitialconversionafterrunningthereactionfor50h.Thismodifiedsampleshowedthebeststabilityamongthetestedthreemodifiedsamples.

  • 标签: ZSM-5沸石 烷基化反应 对二甲苯 催化性能 扫描电子显微镜 NH3-TPD
  • 简介:TheexternalsurfaceofHZSM-5zeolitewaspassivatedbyliquidsiliceousdepositionandbyacidicsitespoisoningwithlepidine,respectively.Thenmethanol-to-hydrocarbons(MTH)reactionwasinvestigatedovertheaboveas-preparedcatalystsandthedissolublecokeontheseusedcatalystswasanalyzedbyGC-MS,tostudytheroleoftheexternalsurfaceofHZSM-5inthecatalyticreaction.ComparisonwiththeexperimentalresultsbasedonparentZSM-5showedthattheproductdistributionofMTHreactionwasobviouslyinfluencedbytheexternalsurface.Evidenceswerelistedasfollows:(1)thefinalproductonparentHZSM-5showedhigheraromaticselectivity,lowerolefinselectivity,lowerratioofC2/C3+aliphaticsandhigherratioofC3/C4+aliphaticsthanthereactionmixtureproducedbythesolecatalysisofacidicsitesinHZSM-5channel;(2)alittleofpentamethylbenzeneandhexamethylbenzeneintheproductonparentHZSM-5,wasproducedviamulti-methylationofmethylbenzeneontheexternalsurface.TheaboveconclusionmayalsobesuitableforMTHreactionoverotherzeoliteswith10-ringchannel.

  • 标签: HZSM-5沸石 产品分布 外表面 芳烃 甲醇 催化反应
  • 简介:π-/π+ratiowasfoundtobeasensitiveprobetothehigh-densitybehaviorofthesymmetryenergybyusingseveraltransportmodels.However,asshowninFig.1,atbeamenergiesbelowthepionproductionthreshold,theeffectsofin-mediumnucleon-nucleonscatteringcrosssection(whichisstillcontroversial)stronglyaffectthevalueofπ??/π+ratio[1].Itisthusnecessarytodoacomparativestudyoftheeffectsofthein-mediumNNcrosssectionandtheeffectsofthesymmetryenergyonpionproductioninheavy-ioncollisionsatlowerbeamenergies.

  • 标签: NUCLEAR SYMMETRY ENERGY
  • 简介:Veryrecently,BelleannouncedtheirobservationofΥ(5S)!bJ!(J=0;1;2),indicatingthattheΥ(5S)!bJ!decaysalsohavelargedecaywidths,i.e.,themeasuredbranchratiosofΥ(5S)!bJ!are<3:410??3,(1:640:23+0:30??0:22)10??3,and(0:570:220:07)10??3withJ=0;1;2,respectively[1].ItshouldbenoticedthateventhoughthetreelevelcontributionstoΥ(5S)!bJ!(J=0;1;2)shouldbestronglysuppressedduetotheOkubo-Zweig-Iizuka(OZI)rule,suchlargedecaywidthsareobserved,whichagaininspiresourinterestinunderstandingsuchquantities.Inthiswork,weproposethatthecontributionfromthehadronicloopshouldbeconsideredinstudyingΥ(5S)!bJ!.

  • 标签: LOOP LOOP BE OUR IT
  • 简介:采用ICP-ASE法对匝迪-5中的Cu,As,Cd,Hg和Pb元素进行了初级形态分析。结果显示Pb和Cu在头煎液和二煎液中的含量之和分别为0.25mg/kg和0.53mg/kg。As,Cd和Hg未检出;人工胃液中Pb的含量为0.02mg/kg,Cu的含量为0.37mg/kg。说明匝迪-5煎煮液和人工胃液中重金属均低于国家药典标准的要求。

  • 标签: 匝迪-5 ICP-ASE 形态研究 重金属
  • 简介:Inthisworktypicalmechanicalpropertiesforacatalystsupportmaterial,ZSM5(aspray-driedgranularzeolite),havebeenmeasuredinordertorelatethebulkbehaviourofthepowdermaterialtothesingleparticlemechanicalproperties.Particleshapeandsizedistributionofthepowders,determinedbylaserdiffractionandscanningelectronmicroscopy(SEM),confirmedthesphericalshapeofthespray-driedparticles.TheexcellentflowabilityofthematerialwasassessedbytypicalmethodssuchastheHausnerratioandtheCarrindex.Thiswasconfirmedbybulkmeasurementsoftheparticle-particleinternalfrictionparameterandflowfunctionusingaSchulzeshearcell,whichalsoillustratedthelowcompressibilityofthematerial.SingleparticlecompressionwasusedtocharacterizesingleparticlemechanicalpropertiessuchasreducedelasticmodulusandstrengthfromHertzcontactmechanicstheory.Comparisonwithsurfacepropertiesobtainedfromnanoindentationsuggestsheterogeneity,thesurfacebeingharderthanthecore.Inordertoevaluatetherelationshipbetweensingleparticlemechanicalpropertiesandbulkcompressionbehaviour,uniaxialconfinedcompressionwascarriedout.ItwasdeterminedthattheAdamsmodelwassuitablefordescribingthebulkcompressionandfurthermorethattheAdamsmodelparameter,apparentstrengthofsingleparticles,wasingoodagreementwiththesingleparticlestrengthdeterminedfromsingleparticlecompressiontest.

  • 标签: ZSM-5沸石 机械性能 颗粒形状 喷雾干燥 催化剂载体材料 扫描电子显微镜
  • 简介:<正>三角形的有关知识是"空间与图形"中最为核心的内容.它包括两类:一是基于一个三角形的知识,包括三角形各个元素之间的关系(边之间的关系、角之间的关系、边与角的关系),以及有关的重要线段(高线、中线、角平分线、中位线);二是基于三角形之间关系的知

  • 标签: 专题复习 角平分线 位线 数学思想方法 对应边 几何变换
  • 简介:Fractionalpyrolysisandone-steppyrolysisofnaturalalgaeCyanobacteriafromTaihuLakewerecomparativelystudiedfrom200to500°C.One-steppyrolysisproducedbio-oilwithcomplexcompositionandlowhighheatingvalue(HHV30.9MJ/kg).FractionalpyrolysisseparatedthedegradationofdifferentcomponentsinCyanobacteriaandimprovedtheselectivitytoproductsinbio-oil.Thatis,acidsat200°C,amidesandacidsat300°C,phenolsandnitrilesat400°C,andphenolsat500°C,weregotasmainproducts,respectively.HZSM-5couldpromotethedehydration,crackingandaromatizationofpyrolyticintermediatesinfractionalpyrolysis.AtoptimalHZSM-5catalystdosageof1.0g,theselectivitytoproductsandthequalityofbio-oilwereimprovedobviously.Themainproductsinbio-oilchangedtonitriles(47.2%)at300°C,indoles(51.3%)andphenols(36.3%)at400°C.Theoxygencontentwasreducedto7.2wt%and9.4wt%,andtheHHVwasraisedto38.1and37.3MJ/kgat300and400°C,respectively.Fractionalcatalyticpyrolysiswasproposedtobeanefficientmethodnotonlytoprovideapotentialsolutionforalleviatingenvironmentalpressurefromwaterblooms,butalsotoimprovetheselectivitytoproductsandobtainhighqualitybio-oil.

  • 标签: HZSM-5催化剂 蓝藻水华 生物油 热解 品质 小数