学科分类
/ 10
191 个结果
  • 简介:说到课程改革,常挂嘴边的就是“更新观念”.一点不错,“改革”是行为,“观念”是思想,行为受思想支配.要转变什么观念?不少人可以说出一大串,但大都只是表达一些陈述性的条文,而行动上却不完全是那么回事,甚至完全不是那么回事.在思考“课改已近十年,而现实教学却并未发生根本性改观”的原因时,我曾以为“咱们并不缺少新的理念,

  • 标签: 物理教学 教学目标 科学素养 立意 课程改革 更新观念
  • 简介:TheCMSCollaborationof2000scientistsinvolves150institutionsfrom31nationsspreadallovertheworld.CMSsoftwaresystemintegrationandreleasemanagementisperformedatCERN.CodemanagementisbasedonCVS,withreadorwriteaccesstotherepositoryviaaCVSserver,Softwareconfiguration,releasemanagementtools(SCRAM)arebeingdevelopedatCERN.Softwarereleasesarethendistributedtoregionalcenters,wherethesoftwareisusedbyalocalcommunityforawidevarietyoftasks,suchassoftwaredevelopmentdetectorsimulationandreconstructionandphysicsanalysis.Dependingonspecificapplication,thesystemenvironmentandlocalhardwarerequirements,differentapproachesandtoolsareusedfortheCMSsoftwareinstallationatdifferentplaces.Thispresentationdescribesconceptsandreactialsolutionsforavarietyofwaysofsoftwaredistribution,withanemphasisontheCMSexperienceatFermilab,Installationandusageofdifferentmodelsusedfortheproductionfarm,forcodedevelopmentandforphysicsanalysisaredescribed.

  • 标签: CMS实验 分布系统 设置系统
  • 简介:TheenigmaticchargedstatesZc(3900),Zc(4020),Zc(4050),Zb(10610),andZb(10650)arestudiedwithinacoupled-channelSchr¨odingermodel[1],whereradiallyexcitedquark-antiquark(qˉq)pairs,withthesameangularmomentaandisospinasthea1(1260)andb1(1235),arestronglycoupledtotheirOkubo-Zweig-Iizuka-allowedde-caychannelsDˉD+ˉDDandDˉD,orBˉB+ˉBBandBˉB,inSandD-wave.Poles,matchingtheexperimentalmassandwidthofalltheabovestates,arefoundbyvaryingonlytwofreeparameters.In

  • 标签: Radially EXCITED AXIAL
  • 简介:Themesonproductioninnucleon-nucleoncollisionsnearthresholdhasthepotentialtogaininformationonhadronpropertiesandalsoplaysanimportantroleinexploringthebaryonspectroscopy[1].Inrecentyears,theexperimentaldatabaseonthereactionofpp!ppK+Knearthresholdhasbeenexpandedsignificantly.Inadditiontothemeasurementsofthetotalanddifferentialcrosssections,belowthethresholdoftheproductionofthe?meson,performedexperimentallywithCOSY-11andANKEdetectorsatthecoolersynchrotronCOSYinGermany,invariantmassdistributionsofvarioussubsystemshavebeenobtainedatlowenergies.Unlikeabovethethresholdoftheproductionofthe?meson,inthelowenergyregion,wedonotneedtoseparatethenon-?fromthe?contribution,andduetothefactthatthedatawerespreadoverawiderangeofK+K??invariantmasses,ithasaspecialadvantagetoinvestigatethescalarmesonsa0(980)$andf0(980)whicharedynamicallygeneratedfromtheinteractionsofK ̄K,ππ,andπηtreatedascoupledchannelsinI=0andI=1,respectively.BothofthemcouplestronglytotheK ̄Kchannel.

  • 标签: PP ADVANTAGE total range has COSY
  • 简介:InfluenceoftheeffectivefermionhexadecapoleforcenewlyincorporatedinamicroscopicsdgIBM-1onspectra,reducedE2andE4transitionmatrixelements(T(E2)sandT(E4)s)intheeven-evenplatinumisotopes(A=192,194,196,198)isinvestigatedintermsofnumericalcalculations.ItisfoundthattheintroducedinteractioncausesonlylimitedmodificationtothespectrumandT(E2)s,apartfromafewexceptions.However,itplaysanessentialroleindescribingE4transitions.Thusinthecasethattheinteractionisincorporatedwithcertainstrength,areasonabledescriptionofalltheE4transitionsintheplatinumisotopesisreachedinthemicroscopicsdgIBM-1incomparingbothtoexperimentaldataandtheresultscalculatedinphenomenologicalbosonmodel.``

  • 标签: 相互作用介子模型 铂同位素
  • 简介:Weproposeandexperimentallydemonstratecompacton-chip1×2wavelengthselectiveswitches(WSSs)basedonsiliconmicroringresonators(MRRs)withnestedpairsofsubrings(NPSs).OwingtotheresonancesplittinginducedbytheinnerNPSs,theproposeddevicesarecapableofperformingselectivechannelroutingatcertainresonancewavelengthsoftheouterMRRs.SystemdemonstrationofdynamicchannelroutingusingfabricateddeviceswithoneandtwoNPSsiscarriedoutfor10Gb∕snon-return-to-zerosignal.Theexperimentalresultsverifytheeffectivenessofthefabricateddevicesascompacton-chipWSSs.

  • 标签:
  • 简介:Atheoreticaldesignispresentedfora1×Mwavelength-selectiveswitch(WSS)thatroutesanyoneofNincomingwavelengthsignalstoanyoneofMoutputports.Thisplanaron-chipdevicecomprisesofa1×Ndemultiplexer,agroupofNswitching'trees'actuatedbyelectro-opticalorthermo-opticalmeans,andanM-foldsetofN×1multiplexers.Treesutilize1×2switches.TheWSSinsertionlossisproportionalto(log2(M+N+1))Alongwithcrosstalkfromtrees,crosstalkispresentateachcross-illuminatedwaveguideintersectionwithintheWSS,andthereareatmostN-1suchcrossingsperpath.TheselossandcrosstalkpropertieswilllikelyplaceapracticallimitofN=M=16upontheWSSsize.Byconstrainingthe1×2switchingenergyto1fJ∕bit,wefindthatresonant,narrowband1×2switchesarerequired.The1×2devicesproposedherearenanobeamMach–Zehndersandasymmetriccontra-directionalcouplerswithgratingassistance.

  • 标签:
  • 简介:为研究空间用四结太阳电池中InGaAsP/InGaAs子电池在电子辐照条件下的性能衰退情况,对InGaAsP/InGaAs双结电池开展了1MeV电子辐照试验,测试了辐照前后的电学参数和量子效率,分析讨论了参数退化情况.结果表明:随着电子注量和位移损伤剂量的增加,电池性能参数退化程度逐渐加大;由位移损伤缺陷导致的载流子寿命减小,是导致电池短路电流和开路电压下降的主要原因;InGaAsP/InGaAs双结电池基区损伤比发射区损伤更加严重,因此,提高其抗辐射能力的关键在于优化基区结构.

  • 标签: InGaAsP/InGaAs子电池 转换效率 量子效率 电子辐照 位移损伤
  • 简介:Magnetoplasmonicsensorsareattractivecandidatesforultrasensitivechemicalandbiomedicalsensorapplications.Avarietyofferromagneticmetalthinfilmshavebeenusedformagnetoplasmonicdeviceapplications,yetthedependenceofsensorperformanceontheopticalandmagneto-opticalpropertiesofferromagneticmetalmaterialshasbeenrarelystudied.Inthiswork,wereportthestudyofenhancedmagneto-opticalKerreffect(MOKE)andsensingperformanceinAu∕FexCo1-xbilayermagneto-opticalsurfaceplasmonresonance(MOSPR)transducers.TheopticalconstantsofFexCo1-x(x=0,0.29,0.47,0.65,and1)inasputter-depositedAu∕FexCo1-xdevicearecharacterizedbytheattenuatedtotalinternalreflection(ATR)method.FexCo1-xthinfilmsshowdifferentMOKEsasafunctionofthechemicalconcentration,withthehighesttransverseMOKEsignalobservedinFe0.7Co0.3.Indexsensingperformanceiscloselyrelatedtothematerial’sopticalandmagneto-opticalconstants.BystudyingthesensingperformanceintheparameterspaceoftheAu∕FexCo1-xbilayerthicknesses,thehighestsensitivityisfoundtobe0.385(theoretical)and0.306RIU-1(experimental)intheAu∕Fe0.7Co0.3MOSPRdevices.OurresearchhighlightstheinfluenceoftheopticalpropertiesofferromagneticmaterialtodevicesensitivityinMOSPRtransducers.ThehighsensitivityinAu∕FexCo1-xMOSPRdevicesmakethesestructuresattractivecandidatesforchemicalandbiomedicalsensingapplications.

  • 标签:
  • 简介:AseriesofRbxCs1-xAg4I5(x=0-1)thinfilmsweregrownbyvacuumevaporationonNaCIcrystalsubstratesat350K.Theabsorptionspectraofthesefilmsweremeasuredat80Kinthewavelengthrangefrom240nmto400nm.ItisshownthatsuperionicconductorthinfilmsofquaternarycompoundRb0.5Cs0.5Ag4I5andternarycompoundRbAg415canbeobtainedatx=0.5-0.6andx=0.7-1,respectively.Atx=0.65,thecombinedcompoundfilmofthemixtureof30mol%RbAg4I5and70mol%Rb0.5Cs0.5Ag4I5ispresented.Then,basedonthespectralpositionsoftheA1andA2peaks,wedeterminedthattheRb0.5Cs0.5Ag4I5excitoncouplingenergyRexis0.21eV,theforbiddenzonewidthEgis3.82eVandtheexcitonradiusaexis0.70hm.Furthermore,theionicconductivitiesofsuperionicconductorthinfilmsofRbAg4I5andRb0.5Cs0.5Ag4I5andtheirmixturefilmareinvestigated,respectively,inthetemperaturerange303K-393K.

  • 标签: 吸收光谱 离子传导性 超离子导体薄膜 真空演化
  • 简介:Inthispaper,adetailedLiesymmetryanalysisofthe(2+1)-dimensionalcouplednonlinearextensionofthereaction-diffusionequationispresented.Thegeneralfinitetransformationgroupisderivedviaasimpledirectmethod,whichisequivalenttoLiepointsymmetrygroupactually.Similarityreductionandsomeexactsolutionsoftheoriginalequationareobtainedbasedontheoptimalsystemofone-dimensionalsubalgebras.Inaddition,conservationlawsareconstructedbyemployingthenewconservationtheorem.

  • 标签: (2+1)-dimensional COUPLED nonlinear REACTION-DIFFUSION equation Lie
  • 简介:Ceria-zirconiasolidsolutionhasbeenpreparedbytheureagrindcombustionandcitricacidsol-gelmethodsforcatalyticapplicationsasoxygenstorage/releasematerialsinthisstudy.Thepropertiesandoxygenstorage/releasecapacitiesofsampleswithdifferentZrcontentswerecharacterizedandevaluatedbyX-raydiffraction(XRD),N2adsorption,scanningelectronmicroscopy(SEM),Ramanspectroscopy,andinsituCO–CO2loopingtest.Theresultsdemonstratethatthesamplespreparedbytwomethodsareallofexcellentlattice[O]release/storagepropertiesandmaintaingoodlong-termcyclestability.ButthepreparationmethodsignificantlyimpactsthehomogeneityofsamplesrelatedtotheirredoxpropertiesandthecontentofZrover20%,whichgreatlychangedthepropertiesofceria-zirconiasolidsolutionsandcausedtheirchangingofcrystallinesymmetryfromcubictotetragonal.Thesamplespreparedbycitricacidsolgelmethodareofmorehomogeneousparticlesizesandhigherspecificsurfaceareasthanthatbyureagrindcombustionmethod,whichisbenefittotheoxygenreleaseratherthanoxygenstorage.ThebulkoxygenamountmigratedtosurfaceincreaseswiththeincreasingZrcontent,however,theamountoflatticeoxygenmigrationdecreaseswhenZrcontentisover20%.WhenZrcontentis20%,thedifferencesofstorage/releasecapacitiesfromtwodifferentpreparationmethodsarereducedathightemperatureinthelong-termloopreaction.

  • 标签: