学科分类
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193 个结果
  • 简介:(Ba0.66Sr0.33)Mg0.8Al11.47O19:Tm0.013+(BSMA:Tm3+)phosphorwassynthesizedbysolid-statereactions.ThesamplewascharacterizedbyX-raydiffraction(XRD),scanningelectronicmicroscope(SEM),vacuumultraviolet(VUV)spectra,ultraviolet(UV)spectraandFT-IRspectrum.XRDpatternrevealsthatBSMA:Tm3+hasthesamestructureasBaAl12O19phase.SEMimageillustratesthatthephosphorhasthehexagonalshapeanddeepslicestructure.VUVandUVemissionspectraat20,50and100Kshowthatthelowtemperatureluminescenceintensitiesbecomeweakgraduallywiththeincreasingofthetemperatureunder147and254nmexcitation.Thestrongbroadbandpeaksataround357and397nmandthepeakat516nmunder147nmexcitationallcorrespondtothecharacteristictransitionsofTm3+ions.However,underUV(254nm)excitation,themainpeakbecomes530nmwhichhasveryhighlineintensity,andthepeaksatabout362and403nmareveryweak.Theexcitationspectrumat20Kshowsthattherearethreeabsorptionpeaksataround153,186and193nmwhen516nmemissionismonitored.Theabsorptionpeaksof[AlO4],[AlO6]andAl-OcanbeobservedinFT-IRspectrum.

  • 标签: VACUUM ULTRAVIOLET low temperature LUMINESCENCE Tm3+
  • 简介:近日德意志央行官网新闻通稿称从2013年底起,截止2016年末,其从美国纽约和法国巴黎将属于德国的583吨黄金运回法兰克福。如此大规模运回黄金储备,使得德国提前完成了原定2020年实现的储备目标。德国人从海外搬回家的这些黄金储备,说起来还有漫长心酸的历史。二战之前,为了防止苏联入侵本土,德国提前把自己的部分黄金储备运往海外储藏。进入冷战时代,东西德分裂,德国98%的黄金储备都存储在英美等远离欧洲前线的地方,确保安全。

  • 标签: 德国人 黄金 法兰克福 法国巴黎 储备 海外
  • 简介:SphericalYAG:Ce3+phosphorparticleswithnarrowsizedistributionwerepreparedbyspraypyrolysis.Theeffectsoftheconcentrationofsolution,theflowrateofcarriergasandtheannealingtemperatureonthephosphormorphologywerestudied.Theproductivityofprecursorparticlesshowsatrendofdropafterrisingwiththeincreaseofconcentration.Raisingtheflowrateofnitrogencanimprovetheproductivityoftheprecursorparticles.Phosphorpreparedbyspraypyrolysishasobviouslyhigheremissionintensitythanthatsynthesizedbysolidstatereaction,spraypyrolysismakesCe3+ionswelldistributedinthecrystallatticeastheluminescentcenters,andphosphorparticleshaveregularsphericityandnarrowsizedistribution.

  • 标签: 钇铝石榴石 稀土 热解 制备 发光二极管 荧光性质
  • 简介:新区3200m3高炉喷煤系统采用中速磨负压制粉,一级高浓度低压脉冲长袋式收粉器收粉。喷吹系统采用双系列双罐并列单管路加分配器浓相输送工艺。喷煤系统按烟煤和无烟煤混喷设计,制粉系统按强爆炸性烟煤设计,最大喷煤比250kg/t,尾气排放煤粉质量浓度≤30mg/m3,喷煤系统投运后,运行正常,烟煤配比达40%,高炉喷吹效果良好。

  • 标签: 高炉 喷煤 制粉 特点
  • 简介:截至2018年,汽运分公司在用6m^3铲运机76台。多年来6m^3铲运机前驱动桥的损坏、维修量一直居高不下,不但加大了修理工的维修工作量,还导致备件费用高,成本压力增大。因此,对6m^3铲运机前驱动桥的损坏进行原因分析,找出症结所在,制定应对措施,就显得尤为重要。

  • 标签: 铲运机 驱动桥 损坏
  • 简介:中铝山西分公司氧化铝3号因转窑窑前鼓风机因轴承失效、机壳移位等原因造成风机振动大,虽更换了轴承恢复了机壳位置,但振动未消除:后采用因素排除的方法,在检修过程中实行过程工序确认制度,最终找出了风机振动大的原因,和对缺陷处理的方法.

  • 标签: 氧化铝 回转窑 鼓风机 振动 动平衡 裂缝
  • 简介:FrequencyupconversionofEr3+inalkalilanthanumgallateglasses(Na2O-La2O3-Ga2O3orNLG)wasinvestigated.Visibleemissionsat532,546,and660nmcorrespondingtothe2H11/2→4I15/2,4S3/2→4I15/2,and4F9/2→4I15/2transitionswereobservedundercontinuouswaveexcitationat980nm.Thequadraticpumppowerdependenceoftheseemissionsindicatedatwophotonupconversionprocess.Atapumpintensityof52W·cm-2at980nm,frequencyupconversionefficienciesof1.1×10-2and2.7×10-3wereobtainedforgreenandredemissions,respectively.

  • 标签: UPCONVERSION FLUORESCENCE GLASSES rare earths
  • 简介:Differentfluxeswereusedtosynthesizelongpersistencephosphors,calciumsulfidesactivatedbyEu2+andTm3+,byconvenientsolid-statemethod.ThephosphorusingNH4Fasafluxhasgoodcrystallinityandlargeparticlesize,itsstabilityagainstwaterandotheratmosphericcomponentsisenhanced,anditsafterglowislongerandfluorescentintensityismoreintensethanthoseofthephosphorusingNH4Clasflux.TheirPLintensitiesvariedwithtimeinmoistairweremeasured,noremarkablechangewasfoundforthosepreparedwithNH4FfluxincontrastwithNH4Clasflux.SousingNH4Fasfluxisagoodmethodtoenhancethestabilityofalkalineearthsulfides.

  • 标签: 磷光体 CaS:Eu^2+/Tm^3+ 化学稳定性 稀土 硫化钙 铕二价
  • 简介:Basedonthethermodynamicallyself-consistentanalysisandoptimizationofthreesub-binarysystemsoftheternarysystemPrCl3-CaCl2-MgCl2,thethermodynamicsofthisternarysystemhasbeenstudied.UsingHillertmodelandtakingMgCl2asanasymmetriccomponent,thePrCl3-CaCl2-MgCl2phasediagramhasbeencalculated.Theagreementbetweencalculatedandmeasuredcompositionsandtemperaturesatdeflectingpointsonliquidusisgood.Thesystemisasimpleeutecticonewithaeutecticpointat26.0mol%PrCl3,41.5mol%CaCl2,32.5mol%MgCl2;560℃(calculated)and26.0mol%PrCl3,39.4mol%CaCl2,34.6mol%MgCl2;546℃(measured),respectively.

  • 标签: TERNARY system Phase DIAGRAM Rare earth
  • 简介:NominalcompositionofCa1-xZnxTiO3:0.002Pr3+(x=0.000~0.200)phosphorswerepreparedbyconventionalsolidreactionroute.XRDandPLmeasurementswereusedtoinvestigatethesolid-solutionstructureandluminescencepropertiesofZn-dopedCa1-xZnxTiO3:0.002Pr3+phosphors.Theeffectofsolid-solutionstructureformedbysubstitutionbetweenCa2+andZn2+ionsontheluminescentpropertieswasanalyzed.Theresultsrevealthat,withtheincreaseofZnsubstitutioncontentbelow0.010,latticeparametersandtheintensityofexcitationpeakatboth260and330nmaswellasthecorresponding610nmemissionintensityaremonotonouslydecreasedquicklyinasimilartendency.Also,theevolutionofluminescenceintensityandcrystalcellparametersagainstZndopingconcentrationareingoodagreement.AboveresultsarecloselyrelatedwiththestructurechangewithinCa1-xZnxTiO3:0.002Pr3+solid-solutionphaseformedbytheZnionssubstitutionfortheCasites.Presentstudyrevealsthatthesolid-solutionstructureformedbysubstitutionbetweenCa2+andZn2+ionshassignificanteffectontheluminescencepropertiesofsinglephaseCa1-xZnxTiO3:0.002Pr3+phosphors.

  • 标签: Ca1-xZnxTiO3 固溶体 发光性能 稀土 掺杂 荧光材料
  • 简介:本文针对选矿过程控制的实现,结合金川集团公司选矿6000t/d扩能项目的配套自动化系统的实践,简要论述了该控制系统的结构,各磨浮控制回路的实现思路和具体实现方法。

  • 标签: 选矿扩能项目 自动化系统 配套
  • 简介:美国宇航局在加州帕萨迪纳的喷气推进实验室研究成功了一种制造YBa2Cu3O7-α高温超导电缆(封装在金属套管内)的新方法。据称,这种方法成本较低,过程易于控制,且对各种前体材料有很强的适应能力。该法分4个步骤:生产具有化学(配)比的前体(Precursor)粉;将前体粉包封在金属套管内;用轧制的方法使前体粉固结;在液态锂金属浴槽内进行处理,使之转变成超导组

  • 标签: 粉末冶金 金属套管 高温超导电缆 锂金属 实验室研究 喷气推进
  • 简介:针对3~#皮带的产尘特点,分别在尾轮和首轮采用独立的防尘系统,加大收尘风量、定向气流排尘、活动刚性密闭、空气幕隔离、扁平罩收尘及低速文丘里除尘器除尘等综合防尘措施,防尘效果良好:3~#皮带工作场所粉尘浓度最高时才1.5mg/m~3,低于粉尘卫生标准2mg/m~3的允许值,尾气排放粉尘浓度最高时达47.0mg/m~3,在卫生标准100mg/m~3的允许范围之内.

  • 标签: 皮带防尘 加大风量 定向排尘
  • 简介:Ceriasphereswithdifferentsizesandsulfurizedproductswithcorrespondingmorphologywerepreparedbyhydrothermalandgas-solidreactionmethodat600–800°CunderCS2atmosphereforashorttime,respectively.Dimensionaleffectinpreparationofγ-Ce2S3wasfirstlyinvestigatedbymeansoftechniquessuchasscanningelectronmicroscopy(SEM),X-raydiffraction(XRD),thermalgravimetricanalysis(TGA)andspectrophotometer.Theresultsshowedthatwhenceriananoparticleswithsmallsizewereusedasprecursors,theγ-Ce2S3couldbepreparedatthelowertemperatureandthebadlysinteredproductswereobtained;whenceriananoparticleswithlargesizewereemployedasprecursors,pureγ-Ce2S3wasdifficultlyobtainedevenifthetemperaturewasupto800°Candtheproductstendedtokeeptheiroriginalsize.Theheat-resistancepropertyoftheγ-Ce2S3withlargesizewasbetterthanthesmallerone,andthepureγ-Ce2S3preparedfromprecursorwithsmallsizehadagoodpigmentaryperformance.

  • 标签: 耐热性能 前体 扫描电子显微镜 颜料 形貌 二氧化铈
  • 简介:针对长江钢铁1250m3高炉的开炉准备工作、开炉参数的选择、填充配料等方面的问题,对开炉及达产过程进行了分析总结.通过精细准备,合理控制操作参数以及调整后续过程,使得此次生产实践过程在工艺控制方面基本做到了平稳有序,实现了顺利开炉、快速达产的预定目标.

  • 标签: 高炉 开炉 达产