学科分类
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95 个结果
  • 简介:Wemeasurethecurrent–voltage(I–V)characteristicsforthesinglecrystalofTl0.4K0.41Fe1.71Se2withthesuperconductingtransitiontemperature(TC)around30.5K,undera10Tmagneticfieldappliedperpendicularandparalleltotheabplane.WefindthattheshapesoftheI–Visothermsareverydifferentfromthedescriptionbythevortex-glass(VG)model.CombiningtheoreticalcalculationsandanalysisoftheρH⊥ab–TandρHab–Tdata,wegiveanexplicitdiscussionoverthesuitabilityoftheVGmodelfortheA0.8Fe2Se2superconductors,andpointoutthepossibilityofthematerialactingasaconvenientplatformforre-examinationandfurtherstudyofthecomplexvortexbehaviorsinthelayeredsuperconductors.

  • 标签: 玻璃模型 适用性 旋涡 单晶 层状超导体 超导转变温度
  • 简介:Ultrafast各向异性的腐烂是揭示ultrafast精力和电子转移的一个突出的参数;然而,由于平行和垂直极化的腐烂动力学的同时的可获得性的要求可靠地坚定是困难的。现在,各向异性的腐烂的任何测量是准确同时性的一种途径。这里,我们为同步ultrafastanisotropy腐烂大小报导一个新奇方法,它能很好决定anisotropy,甚至在一很早的时间,作为刺激激光脉搏的升起的阶段。在与协调刺激在房间温度在答案收获Rhodobactersphaeroides的天线建筑群LH2的细菌的光的B850的各向异性的腐烂被这个方法检测,它显示出30fs的一极化反应时间,并且到在B850戒指的bacteriochlorophylls的从起始的刺激的精力转移拿大约70fs。在吸收光谱的红方面被探查的各向异性的腐烂例如880nm,有0.4的起始的价值,相应于模仿的排放,当有0.1的anisotropy的蓝方面贡献漂白的地面状态时。我们的结果证明盖住整个戒指的协调刺激可能没由于LH2碎的对称被认识到:从在到在答案的C2对称的膜的C9对称。

  • 标签: 各向异性 同步测量 LH2 复合物 细菌 衰减动力学
  • 简介:Theoreticalmodelsofstellarevolutionpredictnegligiblequantitiesof6Li,9Be,and11Binthehydrogenburningphasesofastar’sevolution[1].TheprimordialBig-Bangnucleosynthesis(BBN)modelmightbemoregenerousinitsproductionoftheseelements[2].Theradiative-capturecrosssectionforprotoncaptureon11Bleadingto12CissmallatastrophysicallyinterestingenergiesbecauseofthelargeCoulombbarrier.

  • 标签: FACTORS LOW ENERGIES
  • 简介:我们为f(T)严肃理论在宇宙论的限制的精确上探索SandageLoeb(SL)测试的影响。因为它在远类星体的系列在Lyman-森林里测量redshift飘移,SL测试是对当前的宇宙论的观察的重要补充,盖住2z的redshift沙漠5。避免数据矛盾,当模仿30的基准的模型嘲笑SL测试数据,我们基于当前的联合观察数据使用最好合适的模型。我们确定为f(T)严肃理论的参数评价上的这些SL测试数据的影响。二个典型f(T)模型被考虑,幂定律模型f(T)PL和指数形式的模型f(T)终止。结果证明SL测试罐头有效地打破存在在在另外的宇宙论的观察的今日的事密度m和小瘤常数H0之间的强壮的退化。为考虑f(T)模型,SL测试的30年的观察能极其改进m和H0的限制精确,但是不能有效地改进模型参数的限制精确。

  • 标签: 红移 漂移 测试数据 基准模型 重力 观测数据
  • 简介:在这份报纸,我们学习稳定性局部地旋转地对称(LRS)Bianchi我在通过阶段空间分析的f(T)重力的宇宙模型。我们假设f(T)严肃能被当作象完美的液体一样表现的有效黑暗精力,并且建议在无压力的物质以及黑暗精力之间有相互作用。我们构造方程的相应自治系统检查模型的稳定性因为非幽灵,真空和幽灵分阶段执行。批评的点作为与相比在幽灵阶段仍然保持更稳定,这被结束非幽灵和真空盒子。最后,我们通过一些宇宙论的参数讨论模型的宇宙论的行为。

  • 标签: 相空间分析 宇宙模型 重力 各向异性 稳定性 旋转对称
  • 简介:Inthiswork,webrieflydiscussanovelclassofmodifiedgravitylikef(T,TG)gravity.Inthisbackground,weassumethenewagegraphicversionofpilgrimdarkenergyandreconstructf(T,TG)modelsfortwospecificvaluesofs.Wealsodiscusstheequationofstateparameter,squaredspeedofsoundandwDE-wDEplaneforthesereconstructedf(T,TG)models.Theequationofstateparameterprovidesphantom-likebehavioroftheuniverse.ThewDE-wDEplanealsocorrespondstoΛCDMlimit,thawingandfreezingregionsforbothmodels.

  • 标签: f(T TG) GRAVITY PILGRIM DE models
  • 简介:在偏序度量空间中,获得了一些耦合随机不动点定理,引入F-g-不变集新定义,减弱了F的混合g-单调性,所得结果也是近期文献相关结果的推广.

  • 标签: 混合g-单调性 F-g-不变集 耦合随机不动点
  • 简介:Moleculardynamics(MD)simulationswereperformedtostretchtherectangulargraphenesheetsdopedwithsilicon,nitrogenorboronatoms.Young’smodulus,ultimatestress(strain)andenergyabsorptionweremeasuredforthegraphenesheetswiththedopingconcentration(DC)rangingfrom0to5%.Theemphasiswasplacedonthedistincteffectsofeachindividualdopantonthefundamentalmechanicalpropertiesofgraphene.TheresultsindicatedthatincorporatingthedopantsintographeneledtoanalmostlineardecreaseinYoung’smodulus.Monotonicreductionsinultimatestrength,ultimatestrainandenergyabsorptionwerealsoobserved.Suchdopingeffectswerefoundtobemostsignificantforsilicon,lesspronouncedforboron,andsmallornegligiblefornitrogen.Theoutputsprovideanimportantguidanceforthedevelopmentandoptimizationofnovelnanoscaledevices,andfacilitatethedevelopmentofgraphene-basedM/NEMS.

  • 标签: 下线 服务 迁移
  • 简介:Liquid-phase-exfoliationtechnologywasutilizedtopreparelayeredMoS2,WS2,andMoSe2nanosheetsincyclohexylpyrrolidone.Thenonlinearopticalresponseofthesenanosheetsindispersionswasinvestigatedbyobservingspatialself-phasemodulation(SSPM)usinga488nmcontinuouswavelaserbeam.ThediffractionringpatternsofSSPMwerefoundtobedistortedalongtheverticaldirectionrightafterthelasertraversingthenanosheetdispersions.Thenonlinearrefractiveindexofthethreetransitionmetaldichalcogenidesdispersionsn2wasmeasuredtobe10-7cm2W-1,andthethird-ordernonlinearsusceptibilityχ(3)10-9esu.TherelativechangeofeffectivenonlinearrefractiveindexΔn2e∕n(2e)oftheMoS2,WS2,andMoSe2dispersionscanbemodulated0.012–0.240,0.029–0.154,and0.091–0.304,respectively,bychangingtheincidentintensities.Ourexperimentalresultsimplynovelpotentialapplicationoftwo-dimensionaltransitionmetaldichalcogenidesinnonlinearphasemodulationdevices.

  • 标签:
  • 简介:Inthiswork,theinfluenceofCO2onthestructuralvariationandcatalyticperformanceofNa2WO4/Mn/SiO2foroxidativecouplingofmethanetoethylenewasinvestigated.ThecatalystwaspreparedbyimpregnationmethodandcharacterizedbyXRD,RamanandXPStechniques.AppropriateamountofCO2inthereactantgasesenhancedtheformationofsurfacetetrahedralNa2WO4speciesandpromotedthemigrationofOinMOx,Na,Wfromthecatalystbulktosurface,whichwerefavorableforoxidativecouplingofmethane.WhenthemolarratioofCH4/O2/CO2was3/1/2,enrichedsurfacetetrahedralNa2WO4speciesandhighsurfaceconcentrationofOinMOx,Na,Wweredetected,andthenhighCH4conversionof33.1%andhighC2H4selectivityof56.2%wereobtained.WithfurtherincreaseofCO2inthereagentgases,thecontentofactivesurfacetetrahedralNa2WO4speciesandsurfaceconcentrationofOinMOx,Na,Wdecreased,whilethatofinactivespecies(MnWO4andMn2O3)increaseddramatically,leadingtolowCH4conversionandlowC2H4selectivity.ItcouldbespeculatedthatNa2WO4crystalwastransformedintoMnWO4crystalwithexcessiveCO2addedunderthereactionconditions.PretreatmentofNa2WO4/Mn/SiO2catalystbymoderateamountofCO2beforeOCMalsopromotedtheformationofNa2WO4species.

  • 标签: 结构变化 催化剂 甲烷氧化偶联 Na2WO4 MN2O3
  • 简介:.Thesingle2dilationorthogonalwaveletmultipliersinonedimensionalcaseandsingleA-dilation(whereAisanyexpansivematrixwithintegerentriesand|detA|=2)waveletmultipliersinhighdimensionalcasewerecompletelycharacterizedbytheWutamConsortium(1998)andZ.Y.Li,etal.(2010).Butthereexistnomoreresultsonorthogonalmultivariatewaveletmatrixmultiplierscorrespondingintegerexpansivedilationmatrixwiththeabsolutevalueofdeterminantnot2inL2(R2).Inthispaper,wechoose2I2=(2002)asthedilationmatrixandconsiderthe2I2-dilationorthogonalmultivariatewaveletY={y1,y2,y3},(whichiscalledadyadicbivariatewavelet)multipliers.Wecallthe3×3matrix-valuedfunctionA(s)=[fi,j(s)]3×3,wherefi,jaremeasurablefunctions,adyadicbivariatematrixFourierwaveletmultiplieriftheinverseFouriertransformofA(s)(cy1(s),cy2(s),cy3(s))?=(bg1(s),bg2(s),bg3(s))?isadyadicbivariatewaveletwhenever(y1,y2,y3)isanydyadicbivariatewavelet.Wegivesomeconditionsfordyadicmatrixbivariatewaveletmultipliers.TheresultsextendedthatofZ.Y.LiandX.L.Shi(2011).Asanapplication,weconstructsomeusefuldyadicbivariatewaveletsbyusingdyadicFouriermatrixwaveletmultipliersandusethemtoimagedenoising.

  • 标签: Multi-wavelets FOURIER multipliers image denoising.
  • 简介:Aseriesofoxygenpermeabledual-phasecompositeoxides60wt%Ce0.8Gd0.2O2-δ-40wt%LnBaCo2O5+δ(CGO-LBCO,Ln=La,Pr,Nd,Sm,GdandY)weresynthesizedthroughasol-gelrouteandeffectsoftheLn3+cationsontheirphasestructure,oxygenpermeabilityandchemicalstabilityagainstCO2wereinvestigatedsystemicallybyXRD,SEM,TG-DSCandoxygenpermeationexperiments.XRDpatternsrevealthatthelargerLn3+cations(La3+,Pr3+andNd3+)successfullystabilizedthedouble-layeredperovskitestructureofsinteredLBCO,whilethesmallerones(Sm3+,Gd3+,andY3+)resultedinthepartialdecompositionofLBCOwithsomeimpuritiesformed.CGO-PBCOyieldsthehighestoxygenpermeationflux,reaching2.8×10-7mols-1cm-2at925?Cwith1mmthicknessunderair/Hegradient.TheTG-DSCprofilesin20mol%CO2/N2andoxygenpermeabilityexperimentswithCO2assweepgasshowthatCGO-YBCOdemonstratesthebestchemicalstabilityagainstCO2,possiblyduetoitsminimumbasicity.ThestableoxygenpermeationfluxofCGO-YBCOunderCO2atmosphererevealsitspotentialapplicationintheoxy-fuelcombustionrouteforCO2capture.

  • 标签: CO2 透氧性 双相 化学稳定性 TG-DSC 渗透实验
  • 简介:让G是一个有限的组。让Irr1(G)是G和cd1(G)的非线性的无法缩减的人物的集合在Irr1(G)的人物的度的集合。组G被说如果,是D2-group|cd1(G)|=|Irr1(G)|2。这份报纸的主要目的是分类nonsolvableD2-groups。

  • 标签: 非可解群 有限群 字符集 不可约 非线性 CDL
  • 简介:CO2methanationhasbeenahottopicbecauseofitsimportantapplicationinthespacecraftandpotentialutilizationofcarbondioxide.Nickelcatalystisactiveforthisreaction.However,itsactivitystillneedstobeimproved.Dielectricbarrierdischarge(DBD)plasma,initiatedatambientconditionandoperatedat~150°C,hasbeenemployedinthisworkfordecompositionofnickelprecursortoprepareNi/MgAl2O4.Theplasmadecompositionresultsinhighdispersion,uniquestructure,enhancedreducibilityofNiparticlesandpromotedcatalyst-supportinteraction.AnimprovedactivityofCO2methanationwithahigheryieldofmethanehasbeenachievedovertheplasmadecomposedcatalyst,comparedtothecatalystpreparedthermally.Forexample,themethaneyieldoftheplasmapreparedcatalystis71.8%at300°Cbutitis62.9%overthethermalpreparedcatalyst.ThecatalystcharacterizationconfirmedthatCO2methanationovertheDBDplasmapreparedcatalystfollowspathwayofCOmethanation.

  • 标签: 甲烷化反应 分解催化剂 等离子体 二氧化碳 镍催化剂 介质阻挡放电
  • 简介:IntheinterlayerexpansionofthelayeredzeoliteprecursorCOK-5,aSn,salt,bis(2,4-pentanedionate)-dichlorotin[Sn(acac)2Cl2],insteadofasilylatingagentwasusedtolinkthelayersat180°C.Theobtainedmaterial,whichisdesignedasSn-COE-5,showsashiftofthefirstXRDreflection,whichisverysimilartothatofCOK-5interlayerexpandedwithdichlorodimethylsilane(DCDMS),indicatinganincreaseininterlayerdistance.X-raydiffraction(XRD),N2sorptionisotherms,inductivelycoupledplasma(ICP),andX-rayphotoelectronspectroscopy(XPS)supporttheincorporationofisolatedSnsitesinthesample.Intheconversionofglucosetolevulinicacid,Sn-COE-5exhibitsmuchhigheractivitythanCOK-5,whichisduetothepresenceofLewisacidicsitesintheSn-COE-5.

  • 标签: 前驱体 分子筛 层间 SN 层状 膨胀
  • 简介:TheinfluenceofNa2SO4ontheformationofZnOwhiskerswasinvestigatedinthispaper.ZnOwhiskerswithaspectratiosofupto50weresynthesizedbydissolvingε-Zn(OH)2precursorinNaOH/Na2SO4solutionatroomtemperature,followedbyagingoftheresultingsolutionat140℃for6h.Fouriertransforminfraredspectroscopy,Ramanspectroscopy,andX-rayphotoelectronspectroscopyanalysesrevealedthatSO42-ionswereprimarilyadsorbedonthe(100)planeoftheZnOwhiskersviaanouter-spherecomplexconfiguration(O-H…O),therebypromotingtheone-dimensionalgrowthofZnOwhiskersalongthec-axis.

  • 标签: 氧化锌晶须 硫酸钠溶液 水热合成 X射线光电子能谱分析 傅立叶变换红外光谱 ZnO晶须
  • 简介:Lifetimemeasurementsoflow-lyingexcitedstatesin87Zrand87Nbhavebeenperformedviaandcoincidences.The124MeV32SbeamwasdeliveredfromtheSector-FocusingCyclotron(SFC)oftheHeavyIonR-esearchFacilityinLanzhou(HIRFL).Theparentnuclei87Nband87Mowereproducedbytherespectivereactions58Ni(32S,3p)and58Ni(32S,2p1n),atabeamenergy100MeVthroughthe8mAldegrader.

  • 标签: LOW-LYING EXCITED STATES