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111 个结果
  • 简介:Inthecontextoftopcolor-assistedtechnicolor(TC2)model,westudythechargedandneutraltop-pionsproductionprocessγγ→W~+П_t~-П_t~0.Wefindthattheproductioncrosssectionislargerthanthatoftheprocessγγ→W~+H~-Hintheminimalsupersymmetricstandardmodel.WithreasonablevaluesoftheparametersintheTC2model,thecrosssectioncanreachthelevelofafewfb.Furthermore,theflavor-changing(FC)decaymodeП_t~0→tcisthebestchanneltodetecttheneutraltop-pionduetothecleanSMbackground.Withalargenumberofeventsandthecleanbackground,theneutraltop-pionshouldbeobservableatfuturelinearcollidersoperatinginγγmodeattheTeVenergyscale.

  • 标签: 标准模型 直线对撞机 生产过程 衰变模式 amp 介子
  • 简介:WesuggesttwoschemestogeneratetheWstateofNA-typethree-levelatoms.Intheschemes,identicalNthree-levelatomsaretrappedinacavityorNdistantcavities.ThesuccessorfailureofthegenerationoftheWstatecanbedeterminedbydetectingthepolarizationofphotonleakingoutofthecavity.TheresultdemonstratesthattheWstateisfreefromboththecavitylossandthespontaneousemissionduetothefactthatthetwogroundstates(leftandright)ofthethree-levelatomsarestablestates(ormetastablestates).

  • 标签: 原子物理学 ∧型三层原子结构 光子干涉 W态 单腔 量子纠缠态
  • 简介:研究了不同风速下激光辐照C/C复合材料的氧化速率,利用温度场计算结果,结合氧气在空气中的传质速率,计算了激光辐照下C/C复合材料氧化放热.结果表明,在亚音速的风速下,氧化对C/C复合材料烧蚀的贡献很小,因此,作为激光防护材料,可以忽略C/C复合材料在激光辐照期间的氧化烧蚀.

  • 标签: 氧化烧蚀 氧化放热 C/C复合材料 风速 激光辐照
  • 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.

  • 标签:
  • 简介:WedemonstrateamonolithicsinglefrequencyTm-dopedfiberamplifierwithoutputpowerof51.5W.Asinglefrequencyfiberlaserat1.97μmisamplifiedbyacascadedmasteroscillatorpoweramplifier(MOPA)systemwithall-fiberconfiguration.Theoptical-to-opticalconversionefficiencyofthemainfiberamplifieris45%.Noamplifiedspontaneousemission(ASE)orstimulatedBrillouinscattering(SBS)effectisobservedinthefiberamplifier.Theoutputpowercouldbefurtherscaledbylaunchingmorepumppower.

  • 标签: Single frequency Tm-doped FIBER laser FIBER
  • 简介:Variousagriculturalcropresiduesincludingcornstover,corncob,andsorghumstalkwithamoisturecontentof75wt%weresubjectedtoalongpretreatment(12-60h)withsupercriticalCO2(scCO2),atlowtemperature(50-80℃)andapressureof17.5-25.0Mpa.Thesugaryieldsfromtheenzymatichydrolysis(EH)ofthepretreatedsampleswereasmuchasthree-tofourfoldgreaterthanthoseaffordedbytherawmaterials.However,whenpretreatmentwasconductedwithinashorttime(e.g.0.5h),aspreviouslyreportedintheliterature,onlyaslightincreaseintheEHsugaryieldswasobserved.TheproposedscCO2pretreatmentmechanismdemonstratedtheroleofmoistureinthesystem.Wetting,softening,andswellingwereobservedtomainlyaffectthelignocellulosewhenasuitableamountofwaterwasadded.Finally,thesampleswereanalysedbyX-raydiffractionandscanningelectronmicroscopy,beforeandafterpretreatment,toinvestigatethechangesinthemicroscopicstructureofthebiomass.

  • 标签: LIGNOCELLULOSE scCO2 PRETREATMENT ENZYMATIC HYDROLYSIS SUGAR
  • 简介:Twoschemesforteleportinganunknownone-particlestateareproposedwhenageneralWstateisutilizedasquantumchannel.Inthefirstscheme,afterthesender(Alice)makesaBell-statemeasurementonherparticles,therecipient(Bob)performsaVonNeumannmeasurementandintroducesanauxiliaryparticle,andcarriesoutaunitarytransformationonhisparticleandtheauxiliaryparticle,andperformsaVonNeumannmeasurementontheauxiliaryparticletoconfirmwhethertheteleportationsucceedsornot.Inthesecondscheme,therecipient(Bob)doesnotneedtoperformthefirstVonNeumannmeasurementorintroducetheauxiliaryparticle,whichisnecessaryinthefirstscheme.Itisshownthatthemaximalprobabilitiesofsuccessfulteleportationofthetwoschemesareidenticaliftherecipient(Bob)performsanappropriateunitarytransformationandadoptsaproperparticleonwhichherecoversthequantuminformationofstatetobeteleported.

  • 标签: 未知单粒子态 概率隐形传态 三粒子纠缠 一般W态
  • 简介:Parametersforthe3W1sourceatBSRFweredeterminedinboththededicatedandparasiticmodeandtheirsuitabilityforproteincrystallographybeamlineatBSRFwererealized.Itisdiscussedthatthephysicsmotivationandthedesignofthe3W1iscomparedwithsimilarexperimentalstationsattheBrazilianLightSourec(1.37Gev)andMax-IIinSweden(1.5GeV).Thephotonfluxfromthe3W1sourcdisabout2×10^11photon/smAinthewavelengthrangeof2.0-0.9Ainparasiticmodeand50-80timeshigherinthededicatedmode.Boththededicatedandparasiticmodesaresuitableformacromolecularstructureexperiments.2001ElsevierScienceB.V.Allrightsreserved.

  • 标签: BSRF 北京同步辐射装置 蛋白质 生物化学 结构分析 结晶学
  • 简介:WehavedepositedW/Simultilayermirrorsusingthemagnetronsputteringunderthelowsputteringpressureandthehighmagneticfieldstrength,andmeasuredtheirreflectivtityinBeijingsynchrotronradiationfaciltiy,W/Simultilayershowthepeakreflectivityofapproximately10%ataphotonenergyof1200eVand10.5%ataphotoenergyof700eVrespectivelyattheincidenceangleof81°。

  • 标签: W/Si多层膜 磁控管溅射 X射线反射
  • 简介:Inthispaper,weinvestigateperfectquantumteleportationanddensecodingbyusingan2N-qubitWstatechannel.Inthequantumteleportationscheme,anunknownN-qubitentangledstatecanbeperfectlyteleported.Oneebitofentanglementandtwobitsofclassicalcommunicationareconsumedintheteleportationprocess,justlikewhenusingtheBellstatechannel.WhileN+1bitsofclassicalinformationcanbetransmittedbyonlysendingNparticlesinthedensecodingprotocol.

  • 标签: 隐形传输 编码协议 密集编码 量子态 比特 W态
  • 简介:Amethodtopreparemulti-particleentanglementofGreenberger-Horne-Zeilinger-typeandW-typeisproposedthroughtheinteractionbetweenthecavityandmanyatomssimultaneously.Aftersuitableinteraction,theselectedmeasurementsonthecavityfieldcancreatetheentangledatomicstates.Theseentangledstatescanbeusefulforquantuminformationmanipulationandfundamentalstudyofquantumtheory.ThesestatesthatviolatetheBell'sinequalityareproven.

  • 标签: 多粒子纠缠 贝尔不等式 空腔量子电动力学 GHZ型纠缠 W型纠缠
  • 简介:分子的动态模拟被执行在交流上调查事件精力的效果:从C和H的H电影生长原子流动。我们的模拟证明在低事件精力(1eV)的电影生长被H和C原子的吸附统治。在中等事件精力(10和20eV),有在表面吸附的H原子的事件H原子的抽象反应变得重要。在高事件精力(30和40eV),交流:H电影生长是一个二拍子的圆舞过程:一个人是吸附和C原子的浅培植,并且其它是H原子的深培植。[从作者抽象]

  • 标签: 分子动力学模拟 薄膜生长 入射能量 H原子 交流 流量