学科分类
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355 个结果
  • 简介:H+-restackednanosheetsandnanoscrollspeeledfromK4Nb6O17displaydifferentstructuresandsurfacecharacters.Thetworestackedsampleswithincreasedsurfaceareashaveanamazingvisible-lightresponseforthephotodegradationofdyes,whichissuperiortocommercialTiO2(P25)andNb2O5.Bycomparison,H+/nanosheetshavearelativelyfasterphotodegradationrateoriginatedfromlargeandsmoothbasalplane.Theworkrevealsthatdyeadsorbedontheunfoldednanosheetscaneffectivelyharvestsunlight.Duetofacilepreparation,low-costandhighphotocatalyticefficiency,H+/nanosheetsandH+/nanoscrollsmightbeusedforthevisiblelight-drivendegradationoforganicdyesasasubstituteforTiO2inindustry.

  • 标签: 可见光降解 染料吸附 纳米 堆栈 压入 可见光响应
  • 简介:WithFe(NO3)39H2OandBi(NO3)35H2Oasrawmaterials,differentsillenite-typecompoundsandelementalbismuthwerepreparedbyafacileone-potsolvothermalmethodusingH2O,C2H5OH,(CH2OH)2andC3H8O3assolvents,respec-tively.Thestructure,morphology,elementalcompositionsandpropertiesofsampleswereexaminedbyXRD,SEM,TEM,ICP,XPS,N2adsorptionanddesorption,UV-visDRSandPL.ThephotocatalyticactivitiesofdifferentsampleswereevaluatedbythephotodegradationofRhBundervisible-lightirradiation(λ>400nm),andresultsshowthatBi36Fe2O57preparedusingC2H5OHasthesolventownstheoptimumperformance.Inordertoexplorethereactionmechanism,anadditionalexperimentwasdesignedtoinvestigatethemainactivespeciesduringthephotodegradationprocessviadissolvingdifferenttrappingagentsinthereactionsolutionbeforelightirradiation.TheresultsshowthatsuperoxideradicalanionsplayamajorroleinthissystemsincetheRhBdegradationwassignificantlysuppressedaftertheadditionofbenzoquinone.

  • 标签: PHOTOCATALYSIS sHlenite ELEMENTAL Bi Bi36Fe2O57
  • 简介:Thenear-ultraviolet(n-UV)excitedblue-emittingSr2MgSi2O7:Eu2+phosphorsareusedforfluorescencelampandtricolorwhiteLEDs.Theeffectofnitrogen-dopedonthestructureofthehostandtheenhancementofphotoluminescenceisexperimentallyinvestigated.Theresultsshowthatastheamountofnitrogen-dopedvariesfrom0to0.6(at.),theluminousintensityisfoundtobeincreasedto169%,andthepartialreplacementofObyNresultsinachangeofthecrystalfieldbymodifyingthesymmetryofthecrystalstructure.Asaresult,withthenitrogen-dopedinsmallamount,theluminousintensity,chromaticitycoordinatesandthecolorpuritycanbeadjustedtoadesiredvalueintheapplications.

  • 标签: 蓝色发光 施氮量 荧光粉 发光二极管 Eu 增亮
  • 简介:在答案的膜蛋白质的结构在水晶阶段与那不同。我们在场小角度X光散布的主要结果(萨克斯风管)解决了第一次在净化的答案从光合的bacteriaRhodopseudomonasacidophile收获天线膜蛋白质建筑群LH2的一盏灯的拓扑的结构。我们在答案的LH2建筑群的椭圆的形状清楚地在水晶阶段从它的圆形的结构背离的结果表演由X光衍射决定了。这结果在LH2提供卓见进结构和功能相互影响。

  • 标签: 同步加速器 小角X射线散射 蛋白质膜 晶相
  • 简介:摘要:自改革开放以来,中外文化交流日益频繁,人们逐渐意识到语言作为文化交流的主要工具,基于此时代背景下,语言教育成为时代发展的必然要求,突出表现为英语作为我国学校的必考科目。英汉双语比较教学法往往比单语教学更有效率,同时双语教学也代表着教育者的教学能力与教学水平。本文以双语light up science版本为例,提出英汉双语比较教学法在小学英语教学中的应用策略,希望供以参考。

  • 标签: 小学英语 双语比较教学法 教学应用
  • 简介:ThespinesofpencilandlanceurchinsHeterocentrotusmammillatusandPhyllacanthusimperialiswerestudiedasamodeloflight-weightmaterialwithhighimpactresistance.Thecomplexandvariableskeletonconstruction("stereom")ofbodyandspinesofseaurchinsconsistsofhighlyporousMg-bearingcalciumcarbonate.Thisbasicallybrittlematerialwithpronouncedsingle-crystalcleavagedoesnotfracturebyspontaneouscatastrophicdevicefailurebutbygracefulfailureovertherangeoftensofmillimeterofbulkcompressioninstead.Thiswasobservedinbulkcompressiontestsandbluntindentationexperimentsonregular,infiltratedandlatexcoatedseaurchinspinesegments.MicrostructuralcharacterizationwascarriedoutusingX-raycomputertomography,opticalandscanningelectronmicroscopy.Thebehaviorisinterpretedtoresultfromthehierarchicstructureofseaurchinspinesfromthernacroscaledowntothenanoscale.Guidelinesderivedfromthisstudyseeceramicswithlayeredporosityasapossiblebiomimeticconstructionforappropriateapplications.

  • 标签: sea URCHIN URCHIN SPINES biominmitic mechanical
  • 简介:【摘要】

  • 标签:
  • 简介:Seaurchinspineswerechosenasamodelsystemforbiomimeticceramicsobtainedusingstarch-blendedslipcasting.Porousaluminaceramicswithcap-shapedlayerswithdifferentalternatingporositieswerefoundtohavesuperiorfracturebehaviorunderbulkcompressioncomparedtoceramicswithuniformporosity.Theyfailinacascadingmanner,absorbinghighamountsofenergyduringextendedcompressionpaths.TheporosityvariationinanotherwisesinglephasematerialmimicksthearchitecturalmicrostructuredesignofseaurchinspinesofHeterocentrotusmammillatus,whicharepromisingmodelmaterialsforimpactprotection.

  • 标签: biomimetic engineering sea URCHIN SPINES porous
  • 简介:AseriesofCd1-xZnxS/K2La2Ti3O10compositesweresynthesizedviaasimpleco-precipitationmethod.ThepreparedsampleswerecharacterizedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM),X-rayenergydispersivespectroscopy(EDX),ultraviolet-visiblediffusereflection(UV-Vis),X-rayphotoelectronspectroscopy(XPS)andphotoluminescence(PL)measurements.ThecompositestructuresconsistedofCd1-xZnxSnanoparticlesevenlydistributedonthesurfaceofK2La2Ti3O10.TheabsorptionedgeofK2La2Ti3O10shiftedtothevisiblelightregionuponintroductionoftheCd1-xZnxSnanoparticles.Thephotocatalyticactivitiesofthecatalystswereevaluatedbyhydrogenproductionundervisiblelightirradiation.ThepreparedCd0.8Zn0.2S(30wt%)/K2La2Ti3O10exhibitedhigherphotocatalyticactivity,evolving6.92mmol/gH2undervisiblelightirradiationfor3h.ThepromotedphotocatalyticactivityofthecompositeswasattributedtothesynergisticeffectbetweenCd1-xZnxSandK2La2Ti3O10,whichresultedinenhancedseparationofphotogeneratedelectronsandholes.

  • 标签: Cd1-xZnxS/K2La2Ti3O10 COMPOSITES PHOTOCATALYSIS hydrogen evolution WATER
  • 简介:摘要:能源是现代社会存在和发展的基石,大规模开发利用可再生能源已成为未来我国能源战略的重要组成部分。接下来,我国将大力发展太阳能光伏产业。但是,目前我国在收集和利用太阳能方面仍存在一些问题。其中有一部分原因是太阳在运动过程中,太阳能光伏发电板不能一直被太阳直射,从而未能最大程度利用太阳能。本文基于双轴平衡式追光方式,设计了一个太阳能光伏发电装置,在现有追光技术的基础上,将视日运动轨迹追踪和光电追踪的有机结合,通过对光照强度的自动识别,实现了对太阳光全天候的追踪,提高了太阳能收集效率。

  • 标签: 太阳能光伏发电 双轴平衡式追光系统 太阳能利用率