学科分类
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180 个结果
  • 简介:Ca3Y2(BO3)(4):Eu3+黄磷被高温度solid-statereaction方法综合,并且光特征被调查。排放光谱在相应于电的dipoleD-5(0)的613和621nm展出二强壮的红排出物在365nm刺激下面的Eu3+的-F-7(2)转变,原因是Eu3+代替forY3+在Ca3Y2(BO3)(4)的水晶结构占据非中心对称的位置。为613nm的Theexcitation光谱显示黄磷能是有效地激动的由紫外(紫外)(254nm,365nm和400nm)并且蓝色(470nm)光。Ca3Y2(BO3)(4)的排放紧张上的Eu3+集中的效果:Eu3+黄磷被测量,排放紧张与增加Eu3+集中增加的结果表演,然后减少。Ca3Y2(BO3)(4)的CIE颜色坐标:Eu3+黄磷是(0.639,0.357)在15mol%Eu3+。

  • 标签: 发光特征 高温 固体 光谱
  • 简介:ThenovelverticallystandingPtSe2filmontransparentquartzwaspreparedbyselenizationofplatinumfilmdepositedbythemagnetronsputteringmethod,andanNd:LuVO4passivelymode-lockedsolid-statelaserwasrealizedbyusingthefabricatedPtSe2filmasasaturableabsorber.TheX-raydiffractionpatternandRamanspectrumofthefilmindicateitsgoodcrystallinitywithalayeredstructure.ThethicknessofPtSe2filmismeasuredtobe24nmaccordingtothecross-sectionheightprofileoftheatomicforcemicroscopeimage.High-resolutiontransmissionelectronmicroscopyimagesclearlydemonstrateitsverticallystandingstructurewithaninterlayerdistanceof0.54nmalongthec-axisdirection.Themodulationdepth(AT)andsaturationfluence(Фs)ofPtSe2filmaremeasuredtobe12.6%and17.1μJ/cm2,respectively.Theobtainedmode-lockedlaserspectrumhasacentralwavelengthof1066.573nm,witha3dBbandwidthof0.106nm.Thetransformlimitedpulsewidthofthemode-lockedlaserwascalculatedtobe15.8ps.Amaximumaverageoutputpowerof180mWwithaworkingrepetitionrateof61.3MHzisobtained.Tothebestofourknowledge,thisisthefirstreportofthegenerationofultrafastmode-lockedlaserpulsesbyusinglayeredPtSe2asasaturableabsorber.

  • 标签: 磁控溅射法 通信技术 理论研究 发展现状
  • 简介:Fe_(3–x)O_4raspberryshapednanostructures/graphenenanocompositesweresynthesizedbyaone-steppolyol-solvothermalmethodtobetestedaselectrodematerialsforLi-ionbattery(LIB).Indeed,Fe_(3–x)O_4raspberryshapednanostructuresconsistoforiginalorientedaggregatesofFe_(3–x)O_4magnetitenanocrystals,ensuringalowoxidationstateofmagnetiteandahollowandporousstructure,whichhasbeeneasilycombinedwithgraphenesheets.TheresultingnanocompositepowderdisplaysaveryhomogeneousspatialdistributionofFe_(3–x)O_4nanostructuresatthesurfaceofthegraphenesheets.TheseoriginalnanostructuresandtheirstronginteractionwiththegraphenesheetsresultedinverysmallcapacityfadinguponLi+ionintercalation.Reversiblecapacity,ashighas660mAh/g,makesthismaterialpromisingforanodeinLi-ionbatteriesapplication.

  • 标签: 纳米复合材料 锂离子电池 覆盆子 石墨 FE 性能
  • 简介:Two-dimensional(2D)graphitecarbonnitride(g-C3N4)nanosheetshavebeensuccessfullyusedasasaturableabsorber(SA)inapassivelyQ-switchedNd:LLFlaserat1.3μmforthefirsttime,tothebestofourknowledge.Underanincidentpumppowerof9.97W,theshortestpulsedurationof275nswasacquiredwithoutputpowerof0.96Wandpulserepetitionrateof154kHz,resultinginapulseenergyof6.2μJ.Inaddition,thesaturableabsorptionbehaviorsofzero-dimensional12nmg-C3N4nanoparticles(g-C3N4-NPs)andthree-dimensionalorderedmesoporousg-C3N4(mpg-C3N4)werealsoobserved,althoughtheirmorphologyandstructurewerequitedifferentfrom2Dg-C3N4.Theexperimentalresultsintroducethepotentialapplicationofg-C3N4nanomaterialsasSAsinQ-switchedlasers.

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  • 简介:Theelectronicstructures,dielectricfunctions,complexrefractiveindicesandabsorptionspectraforaperfectPbW04(PWO)crystalandthePWOcrystalscontainingleadvacancyV^2-pbhavebeencalculatedusingafull-potential(linearized)augmentedplane-wave(LAPW)+localorbitals(LO)methodwiththelatticestructureoptimized.Thepeaksoftheabsorptionspectracorrespondingtotheelectronictransitionshavebeenstudied.

  • 标签: 电子结构 光学性质 钨酸铅晶体 V^2-pb 线性平面波法
  • 简介:我们从intra洞表明红轻femtosecond激光脉搏的产生加倍频率的Cr4+:forsterite激光。75mW的平均产量力量被在激光洞插入500-m-thickBBO晶体与55fs的脉搏宽度在647nm的中央波长获得。第二泛音脉搏的光谱的带宽是9nm,相应于0.355的一个时间带宽产品。

  • 标签: 镁橄榄石激光器 飞秒脉冲 腔内倍频 红光 时间带宽积 飞秒激光脉冲
  • 简介:Siliconcarbidefiber/siliconcarbidematrix(SiCf/SiC)compositesareofinterestasafuelcladdingandstructuralmaterialindesignsofadvancednuclearreactorduetotheirsuperiorthermo-mechanicalpropertiesandstabilitiesandlowcross-sectionforneutroncaptureunderthesevereserviceenvironmentincludinghightemperatureandhighenergyneutronbombardment.SiCf/SiCcompositionsconsistsofSiCfiberandSiCmatrixwhichexistinwellover100polymorphsdependentonthevariedstackingofSi-Cclose-packedatomicplanes,2H-SiC,4H-SiC,6H-SiC,3C-SiC,15R-SiC,etc.EnergeticHeatomscanbecreatedandaccumulatedvianuclearreactions.HeatomsagglomerateandcoarsenintoHebubblesandcandeterioratestructuralpropertiesbyinducingcrackandcreep.Inthisexperiment,thedamageofn-type4H-SiCwafers(researchstandard,suppliedbytheCreeResearchInc.)withathicknessof0.38mmimplantedwith100keVHe+toafluenceof31016He+/cm2andpost-implantation-annealedbehavioratdifferenttemperaturewerestudiedusingRamanscatteringspectroscopy.

  • 标签: INVESTIGATION Spectra RAMAN
  • 简介:Weexperimentallydemonstratedadiode-pumpedKerr-lensmode-lockedfemtosecondlaserwithaYb:CaYAlO4crystalasthegainmedium.Pulsedurationasshortas33fswasobtaineddirectlyfromtheoscillatoratarepetitionrateof115MHz.Thecentralwavelengthwasat1059nmwithaspectralbandwidthof49nm.Theseare,tothebestofourknowledge,theshortestpulsesgeneratedfromaYb:CaYAlO4oscillator.

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  • 简介:本文考察了稀土氧化物,合金和氧化锆对AlPO5载体和Fe/AlPO5催化剂的影响。结果表明,La、Ce和Y稀士氧化物的引入可有效地促进硝酸铁丙酮溶液中制备的Fe/AlPO5催化剂在CO加氢反应中的催化活性;负载不同合金的AlPO5催化剂具有明显不同的催化反应结果;ZrO可调变AlPO5载体的表面性能,削弱活性组份和载体间的相互作用,使在硝酸铁水溶液中制备的催化剂在合成气转化中具有一定的催化活性。更多还原

  • 标签: 助剂 AlPO4-5分子筛 CO加氢
  • 简介:One-potachievementofethyllevulinatefromcassavawasconductedinethanol-watersystemoverseveralsimplesulfatesaltcatalysts.Al2(SO4)3catalysthadthebestperformanceinsynthesizingethyllevulinatecomparingwiththoseofaseriesofsulfatesalts.Thehighestyieldsofethyllevulinatewasupto39.27%aswellas7.78%levulinateacidwhencassavawascatalyzedinethanolmediumbyadding10wt%water.13Cand1HNMRspectroscopicinvestigationsconfirmedthatisomerizationofglucosetofructoseoverAl2(SO4)3catalystisanimportantstepinproducingethyllevulinateandlevulinateacid.DuetoaggregationsofAl3+underhydrothermalconditions,tinyamountofAl3+weredetectedinfiltrateatthepercentageof0.32%evenifinabsolutewater.BronstedandLewisacidscouldimprovetheyieldofethyllevulinateandlevulinateacidbysynergisticeffect.AllresultssuggestedthatA12(SO4)3wasasimpleandefficientcatalystforethyllevulinateandlevulinateacidproduction.

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  • 简介:WehavesynthesizedandinvestigatedphysicalpropertiesoftwonewquaternarycompoundsGd2CoAl4T2(T=Si,Ge)singlecrystals,whichareisostructuraltoTb2NiAl4Ge2andEr2CoAl4Ge2.Themostimportantstructuralfeatureofthesematerialsistheanti-CaF2-typeCoAl4T2slabs.Thesematerialsshowmetallicbehaviorbelow300Kandthereisalong-rangeantiferromagnetic(AFM)transitionappearingat20and27KforGdCoAl4Ge2andGd2CoAl4Si2,respectively.ResistivityandheatcapacitymeasurementsalsoconfirmthesebulkAFMtransitions.Furtheranalysisindicatesthatthislong-rangeantiferromagnetismshouldresultfromthemagneticinteractionbetweenlocalmomentsofGd^3+ions.

  • 标签: magnetic MAT erials RARE earth COMPOUNDS
  • 简介:对制造的单mesa终端4H-SiCPIN二极管,采用数值仿真和测试结果比对的方法,分析了各向异性迁移率效应对4H-SiCPIN二极管正向直流特性的影响。详细阐述了器件的正向直流仿真物理模型和参数选取,其中,迁移率的各向异性关系是在各向同性迁移率模型的基础上引入的,载流子寿命采用空间赋值的方法代入模型进行计算。对比结果显示,采用各向同性迁移率模型的仿真结果与实验值偏差较大,对迁移率模型进行各向异性修正后,仿真结果与实验结果符合得较好。研究表明,实际制造的4H-SiCPIN二极管在直流开态下,存在迁移率的各向异性效应。

  • 标签: 4H-SIC PIN二极管 正向直流特性 数值仿真 各向异性迁移率
  • 简介:Severecapacityfadingandpoorhighrateperformanceoflithiumsulfur(Li-S)batterycausedby"shuttleeffect"andlowconductivityofsulfurhampersitsfurtherdevelopmentsandapplications.Li4Ti50i2(LTO)possesseshigh1whiumionconductivity,anditisalsocanbeusedasanactiveadsorbentforpolysulfide.Herein,fineLTOparticlecoatedcarbonnanofibers(CNF)werepreparedandaconductivenetworkbothforelectronandlithiumionwasbuilt,whichcangreatlypromotetheelectrochemicalconversionofpolysulfideandimprovetherateperformanceofLi-Sbatteries.Meanwhile,aquantityofadsorptionsitesisconstructedbydefectsofthesurfaceofLTO-CNFmembranetoeffectivelyimmobilizepolysulfide.ThemultifunctionalLTO-CNFinterlayercouldimpedetheshuttleeffectandenhaneecomprehensiveelectrochemicalperformanceofLi-Sbatteries,especiallyhighrateperformanee.WithsuchLTO-CNFinterlayer,theLi-Sbatterypresentsaspecificcapacityof641.9mAh/gat5Crate.After400cyclesat1C,acapacityof618.0mAh/gisretained.ThisworkprovidesafeasiblestrategytoachievehighperformanceofLi-Sbatteryforpracticalutilization.

  • 标签: Lithium sulfur batteries LI4TI5O12 (LTO) INTERLAYER
  • 简介:Ablackphosphorus(BP)saturableabsorber(SA)solutionwithdifferentconcentrations(1.0and0.5mg/ml)isfabricatedwiththeliquid-phaseexfoliationmethod.ByusingtheBP-SA,acompactdiode-pumpedpassivelyQ-switchedNd:YV04laserisdemonstrated.OnereflectingBragggratingsisusedastheoutputcouplerformodeselection.ByinsertingthoseBP-SAsolutionsinthelasercavity,themaximumsinglelongitudemode,Q-switchedoutputpowersof126mWat692.5kHzand149mWat630.3kHzareachievedatthepumppowerof8.0W,correspondingtothepulsedurationsof144nsand196ns,respectively.Moreover,longitudinal-modecharacteristicsofQ-switchedoutputlaserindifferentopticalcavitylengthsbasedontwo-kindBP-SAsolutionconcentrationsareinvestigated.OurresultsshowthatBP-SAcouldalsobedevelopedasaneffectiveSAfortheQ-switched,singlelongitudinalmodepulselaser.

  • 标签: A SINGLE-LONGITUDINAL-MODE Passively Q-SWITCHED Nd:YVO4 Laser