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212 个结果
  • 简介:Veryrecently,theBelleandBESIIIexperimentsobservedanewcharmonium-likestateX(3823),whichisagoodcandidatefortheD-wavecharmonium(13D2).BecausetheX(3823)isjustneartheDˉDthreshold,thedecayX(3823)!J=+??canbeagoldenchanneltotestthesignificanceofcoupled-channeleffects.Inthiswork[1],thisdecayisconsideredincludingboththehidden-charmdipionandtheusualquantumchromodynamicsmultipoleexpansion(QCDME)contributions.

  • 标签: IDENTIFY COUPLED-CHANNEL EFFECTS
  • 简介:3个不同的年龄20、30、40,不同的爱好,不同的经历,却在同样的城市,同样为了自己的灵感,选择了同样的maneger生活。

  • 标签: 年龄层 生活 经历 爱好
  • 简介:Broadband(1.6–18THz)terahertztime-domainspectroscopy(THz-TDS)andtime-resolvedterahertzspectroscopy(TRTS)wereperformedona54μmthickchalcogenideglass(As30Se30Te40)samplewithatwo-colorlaser-inducedairplasmaTHzsystemintransmissionandreflectionmodes,respectively.Twoabsorptionbandsat2–3and5–8THzwereobserved.TRTSrevealsanultrafastrelaxationprocessofthephotoinducedcarrierresponse,welldescribedbyarateequationmodelwithafiniteconcentrationofmid-bandgaptrapstatesforself-trappedexcitons.ThephotoinducedconductivitycanbewelldescribedbytheDrude–Smithconductivitymodelwithacarrierscatteringtimeof12–17fs,andweobservesignificantcarrierlocalizationeffects.Afastrefractiveindexchangewasobserved100fsbeforetheconductivityreacheditsmaximum,with2ordersofmagnitudelargeramplitudethanexpectedfortheopticallyinducedTHzKerreffect,indicatingthatfreecarriersareresponsibleforthetransientindexchange.

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  • 简介:Theground-stateandthermodynamicpropertiesofquantummixed-spinchainsof1/2-1/2-1-1and3/2-3/2-1-1areinvestigatedbyaquantumMonteCarlosimulationwiththeloop-clusteralgorithm.For1/2-1/2-1-1chain,wefindithastwophasesseparatedbyanenergy-gapvanishingpointintheground-state.For3/2-3/2-1-1chain,thenumericalresultsshowtwoenergy-gapvanishingpointsisolatedbydifferentphasesinitsground-state.Ourcalculationsindicatethatallthesegroundstatephasescanbeunderstoodbymeansofvalence-bond-solidpicture,andthethermodynamicbehavioratfinitetemperaturesiscontinuousasafunctionofparameterα=J2/J1.

  • 标签: 蒙特卡罗模拟 混合自旋链 铁磁性 基态 热力学性质 能隙
  • 简介:爆炸逻辑网络是用炸药非常规爆轰特性实现的传爆序列,它由多个爆炸逻辑单元(逻辑零门、与门和破坏性交叉通路)组成,主要运用在定向战斗部等常规武器系统中,起引爆控制作用。2005年,研制出爆炸逻辑零门(设计参数间隙L为0.3~2.1)、破坏性交叉通路(设计参数夹角动35°~60°)。但是作为应用技术,爆炸逻辑网络的可靠性关系到整个武器系统可靠性,关系到武器能否准确打击预定目标。

  • 标签: 爆炸逻辑网络 系统可靠性 破坏性 通路 武器系统 设计参数
  • 简介:描述了一种采用HPGe探测器γ能谱法无损测量核材料铀样品并计算样品的生产(纯化)年龄与同位素丰度的方法。该方法不需要其他任何标准源或参考源,对样品的形态(固体、液体)和形状没有限制,由铀样品自身所含多γ射线核素的γ能峰来刻度相对峰效率曲线,由能峰计数率、相对效率、γ射线发射概率等参数确定铀同位素的比值,由^234U与其衰变子体214Bi的活度比值计算其生产年龄。对一个铀总量约5g、^235U浓缩度约90%的24mL液体铀样品,用两套HPGe探测器分别测量不同能区范围的γ能谱:在平面型探测系统获取的低能区能谱中,用^235U的γ能峰刻度相对峰效率曲线,计算了^234U、^228Th(232U子体)与235U的相对比值;在同轴型探测系统获取的高能区能谱中,用^228Th及其子体的γ能峰刻度相对峰效率曲线,计算^238U、^214Bi与^228Th的相对比值,综合计算得到铀样品生产年龄(-32a)及铀同位素丰度,并与样品经过放化分离后,质谱法测量得到的结果进行了比较,生产年龄与丰度比偏差均在5%以内符合。

  • 标签: 高浓铀 铀年龄 丰度 Γ能谱 相对峰效率
  • 简介:TheGroupofEnergyMaterials(GEM)inIMPisengagedintheirradiationresponseofmaterialscandidatetoadvancednuclearenergysystems(GenIV,fusionreactors).Themajorprogressofresearchinourgroupin2016isintheirradiationhardening/embrittlementofoxide-dispersion-strengthened(ODS)ferriticsteelsandVanadiumalloys,andinthemechanismsunderlyingdamageproductioninsiliconcarbide(SiC)fibers.Abriefdescriptionisgivenasfollows.1.EffectoftheoxidenanoparticlesontheirradiationhardeningofODSferriticsteelsTheinfluenceofoxidenanoparticlesontheirradiationresistanceofODSferriticsteelsisacrucialissuefortheupgradeofODSsteels.

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  • 简介:Heavyionbeamsaregenerallyrecognizedasoneofpowerfulmutagensinplantbreedingtogeneratenewmutantswithidealorusefulagronomiccharacters[1].12C6+ionbeams(80MeV/u)acceleratedbyHeavyIonResearchFacilityinLanzhou(HIRFL)wereusedtoirradiatewheatsamples,oneofthemajorwheatvarietiesinQinghaiprovince,namedGaoyuan448.Theradiationdosesrangedfrom10to200Gy.Theirradiatedsamples,controls,andanothermajorwheatvarietynamedAbowereplantedinfarmlocatinginLeducountyofQinghaiprovincein2014.

  • 标签: MUTATION BREEDING IRRADIATED
  • 简介:1.河水总是向低处流,抛出的物体总会落向地面,这些现象说明,地球上的物体总是要受到________力的作用,该力的施力物体是______。

  • 标签: 重力 中等教育 物理教学 课外教材
  • 简介:Study on IMF Emission in 30 MeV/u 40Ar Induced ReattionsStudyonIMFEmissionin30MeV/u40ArInducedReattions¥ZhuYongtai;XuHus...

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  • 简介:In2014,theresearchersofTheoreticalPhysicsGroupatIMPhavecarriedouttheirresearchworkonnuclearphysics,heavyionphysicsandhadronphysics.Someimportantresultshavebeenobtained.Thethree-bodyforce(TBF)effectontheoff-shellbehavioroftheneutronandprotonmassoperatorsinasymmetricuclearmatterhasbeeninvestigatedwithintheframeworkoftheextendedBrueckner-Hartree-Fockapproach[1].Athighdensitieswellabovethenormalnuclearmatterdensity,theTBFisshowntoaffectsignificantlytheoff-shellehaviorofboththeprotonandneutronmassoperators.Thedensitydependenceofsymmetryenergyaroundtheuclearsaturationdensityhasbeenstudied[2].Anewapproachhasbeenproposedandappliedtodeterminetheymmetryenergycoefficientofheavynucleibasedontheavailableexperimentalnuclearmassesofheavynuclei.Theobtainedresultisadoptedtoanalyzethedensitydependenceofsymmetryenergyofnuclearmatteraroundtheaturationdensity.TheslopeparameteratthesaturationdensityisdeterminedtobeL=(50.515.5)MeV.

  • 标签: THEORETICAL PHYSICS GROUP
  • 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:Tostudytheelectromagnetic(EM)backscattercharacteristicsoffreakwavesatmoderateincidenceangles,weestablishanEMbackscatteringmodelforfreakwavesin(1+1)-dimensionaldeepwater.ThenonlinearinteractionbetweenfreakwavesandBraggshortwavesisconsideredtobethebasichydrodynamicspectramodulationmechanisminthemodel.NumericalresultssuggestthattheEMbackscatteringintensitiesoffreakwavesarelessthanthosefromthebackgroundseasurfaceatmoderateincidenceangles.Thenormalisedradarcrosssections(NRCSs)fromfreakwavesarehighlypolarisationdependent,evenatlowincidenceangles,whichisdifferentfromthesituationfornormalseawaves;moreover,theNRCSoffreakwavesismorepolarisationdependentthanthebackgroundseasurface.NRCSdiscrepanciesbetweenfreakwavesandthebackgroundseasurfacewithusinghorizontaltransmittinghorizomtal(HH)polarisationarelargerthanthoseusingverticaltransmittingvertical(VV)polarisation,atmoderateincidentangles.NRCSdiscrepanciesbetweenfreakwavesandbackgroundseasurfacedecreaseswiththeincreaseofincidenceangle,inbothHHandVVpolarisationradars.Asanapplication,inthesynthetic-apertureradar(SAR)imagingoffreakwaves,wesuggestthatfreakwavesshouldhaveextremelylowbackscatterNRCSsforthefreakwavefacetwiththestrongestslope.Comparedwiththebackgroundseasurface,thefreakwavesshouldbedarkerinHHpolarisationechoimagesthaninVVechoimages,inSARimages.FreakwavescanbemoreeasilydetectedfromthebackgroundseasurfaceinHHpolarisationimagesthaninVVpolarisationimages.Thepossibilityofdetectionoffreakwavesatlowincidenceanglesismuchhigherthanathighincidenceangles.

  • 标签: 电磁散射 深层水 水体污染 EM
  • 简介:ThesplittingofpotentialenergylevelsforgroundstateX2ΠgofOx2(x=+1,1)underspin–orbitcoupling(SOC)hasbeencalculatedbyusingthespin–orbit(SO)multi-configurationquasi-degenerateperturbationtheory(SO-MCQDPT).TheirMurrell–Sorbie(M–S)potentialfunctionsaregained,andthenthespectroscopicconstantsforelectronicstates2Π1/2and2Π3/2arederivedfromtheM–Sfunction.TheverticalexcitationenergiesforOx2(x=+1,1)areν[O+12(2Π3/2→X2Π1/2)]=195.652cm1,andν[O12(2Π1/2→X2Π3/2)]=182.568cm1,respectively.Allthespectroscopicdataforelectronicstates2Π1/2and2Π3/2aregivenforthefirsttime.

  • 标签: 分子结构 势能函数 自旋轨道耦合 电子态
  • 简介:Grapheneistwodimensionalmaterialswhichismadeofhoneycombedcarbonatoms.Itattractsextensiveinterestsforitswonderfulcharacteristicsthatmakethegrapheneapotentialcandidateinfieldsofmicroelectronicsproduction,moleculedetection,desalinationandDNAsequencing.Highlychargedion(HCI)hashugepotentialenergyforpeelingoffelectrons.Wheninteractingwithsolidsurface,theHCIdistortedthesolidlatticeviapotentialdepositionandthenthenanostructureswereformedonthesolidsurface.TheHCIwasexpectedasatoolforsurfacemodification.Inthiswork,HOPGandgraphemewereirradiatedwithXeq+andArq+ions.ThetypicalRamanspectraofgrapheneandHOPGirradiatedwithhighlychargedionswereshowninFig.1.TheDpeakappearedat1335cm??1onthespectraofgrapheneirradiatedwithhighlychargedions.TheintensityofDpeakincreasedwithfluence.TheratioofintensityofDpeaktothatofGpeakvariedwithfluenceinFig.2.Theratioroselinearlywiththesquarerootoffluencewhenfluencewaslow.Theratiosaturatedwhentheirradiationfluencewashigh.Thecriticalfluencedependedonthechargestateofion.Thehigherchargestateitwas,thelowercriticalfluenceitwouldbe.

  • 标签: CHARGE SPECTRA GRAPHENE
  • 简介:当堂反馈1.如图所示,锤子对钉子的作用力的施力物体是——,受力物体是——.画出锤子对钉子的作用力的示意图.

  • 标签: 压强 训练 同步 作用力 示意图 物体
  • 简介:1.将手掌压在水平的桌面上,使手掌水平向前运动,会感到手掌受到桌面向__________(选填“前”或“后”)的作用力,此力称为______力.桌面越光滑,手掌受到的力越小,表明____________________________________。

  • 标签: 摩擦力 水平向 作用力 桌面