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347 个结果
  • 简介:0概述在制定企业的生产经营战略目标与措施时,对企业自身在市场竞争中的——劣势进行评价分析是最重要的基础工作之一。这项工作的目的主要是准确地阐明并确认企业在与其主要或潜在竞争对手竞争中的、劣势状况,再结合企业环境的分析,为拟定企业生存与发展的长期战略目标及措施提供指导。

  • 标签: 战略计划 模型 综合评价值
  • 简介:ThephaseandmorphologytransformationduringthehydrothermaltreatingprocessofY2O3wasevaluatedwithX-raydiffcrcnce(XRD),scanningelectronmicroscopy(SEM),transmissionelectronmicroscopy(TEM),particlesizeandspecificsurfaceareadetermination.TheresultsshowedthatthecubicY2O3didnottransferintohexagonalY(OH)3inpurewater.Therefore,purehexagonalY(OH)3withnanotubeandmicrorodmorphologieswereobtainedbyhydrothermaltreatingY2O3at150℃for12hin15mlof2mol/LNaOHsolutionwithandwith-outPVAorPEGItwassuggestedthatthecharacteristicpreferentialgrowthofY(OH)3wasattributedtothestructureanisotropyofhexahedronY(OH)3.TheadditionofPVAorPEGcouldpromotetheformingprocessofnanotubesbyselectiveadsorptionondifferentcrystalplanes,whichalteredthegrowthratealongdifferentdirectionsandresultedinthediffusionlimitofconstructingionsinthecentertopofrods.Finally,Y(OH)3:EuandY2O3:Eunanotubeswerealsosynthesizedbyusingthismethod,andtheirphotoluminescencepropertieswereevaluated.

  • 标签: HYDROTHERMAL synthesis Y(OH)3 Y(OH)3:Eu Y2O3:Eu NANOTUBE
  • 简介:Thesolutionreactionmechanisms,composition,donoratoms,propertiesofcoordinatelinkandstabilityofthecomplexesonthesystemsofadrenalinewithNa3+,Gd3+andTm3+havebeenstudiedbypH-potentiometrictitrationandelectronicspectroscopy.Adrenalineperturbsthef-felectronictransitionofNd3+andTm3+sothattheabsorptionspectraoftheircomplexesareshiftedtowardlongerwavelengths.Theabsorptionspectraofthecomplexesformedbythethreef-blockelementionswithadrenalineareshiftedtowardshorterwavelengthswiththeincreaseofPHinΔγ=350~650nm

  • 标签: ADRENALINE NEODYMIUM GADOLINIUM THULIUM Solution EQUILIBRIUM
  • 简介:YbAl3(BO3)4crystalofgoodopticalqualitywasgrownbythefluxmethod.ThestructureofYbAl3(BO3)4crystalwasdeterminedbysingle-crystalX-raydiffraction.TheexperimentshowsthatYbAl3(BO3)4belongstothedoubleborateswithatrigonalstructure.ThespacegroupisR32anditsunitcellconstantsweremeasuredtobea=0.92965nm,c=0.72129nm,V=0.53673nm3,Z=3.Thetransmittancespectraweremeasured.Thecut-offofYbAl3(BO3)4crystalis216nm,andtherearetwoabsorptionpeakslocatedat940and975nmfrom190nmto2600nm.ThethermalpropertiesofYbAl3(BO3)4crystalwerestudiedforthefirsttime.Theaveragethermalexpansioncoefficientsweredeterminedtobe2×10-6/℃,9.5×10-6/℃alonga-andc-direction.ThespecificheatofYbAl3(BO3)4crystalwasmeasuredtobe0.6695J·(g·℃)-1atroomtemperature.AllresultsindicatethattheYbAl3(BO3)4crystalisanexcellentstoichioimetriclasermaterial.

  • 标签: YbAl3(BO3)4 CRYSTAL TRANSMITTANCE SPECTRA thermal properties
  • 简介:Er3+-Tm3+-Yb3+tri-dopedBaMoO4phosphorsweresynthesizedbyco-precipitationtechniqueandcharacterizedbyX-raydiffractionanalysis,absorptionstudyandfieldemissionscanningelectronmicroscopyanalysis.Upconversionaswellasdownconversionluminescencestudieswereperformedbyusingnearinfrared(980nm)andultraviolet(380nm)excitations.Energyleveldiagram,pumppowerdependenceandcolourcoordinatestudywereutilizedtodescribethemulticolorupconversionemissionproperties.Undersingle980nmdiodelaserexcitationthedualmodesensingbehaviourisrealizedviaStarksublevelsandthermallycoupledenergylevelsoftheTm3+andEr3+ionsinthepreparedtri-dopedphosphors.AcomparativefluorescenceintensityratioanalysisforintegratedemissionintensitiesarisingfromtheStarksublevels{1G4(a)and1G4(b)}andthermallycoupledenergylevels{2H11/2and4S3/2}oftheTm3+andEr3+ions,respectivelywascarriedoutinthepreparedtri-dopedBaMoO4phosphors.ThemaximumsensitivityforthermallycoupledenergylevelsoftheEr3+andStarksublevelsoftheTm3+ionwasreported.Thedevelopedphosphorscouldbeusefulinthedisplaydevicesandopticalthermometricapplications.

  • 标签:
  • 简介:本文采用高温团相反应合成TCaTiO3∶Pr3+红色发光材料、报道了Pr3+激活的CaTiO3的光谱特征及长余辉特性,并与CaS∶Eu的光谱特性及长余辉进行了比较。CaTiO3∶Pr3+将是一种具有广泛用途的新材料

  • 标签: CaTiO3∶Pr3+ 合成 发光特性 长余辉
  • 简介:介绍了武山铜矿中段运输系统原3m3底侧卸矿车的设计特点。结合生产实际状况,对3m3底侧卸矿车在运行过程中出现的问题进行了分析,总结产生故障的原因,针对性的提出改进措施。现场使用表明,通过改进后,取得了良好效果,满足了矿山生产的需要。

  • 标签: 底侧卸矿车 轮轴 卸载轮 车箱 改进措施
  • 简介:Eu3+activatedSr1–xEuxZrO3(x=0.01–0.04)phosphorwithperovskitestructurewassuccessfullysynthesizedbyusingcombustionmethod.Thestructure,morphologyandopticalpropertiesofthematerialwerecharacterizedbyX-raydiffraction,scanningelectronmicroscopyandfluorescencespectrometry.TheXRDresultsindicatedthatcrystalsofSrZrO3:Eu3+belongstotetragonalperovskitesystem.ThephosphorcouldbeeffectivelyexcitedbyUVlightandtheemissionspectraresultsindicatedthatreddish-orangeluminescenceofSrZrO3:Eu3+duetomagneticdipoletransition5D0→7F1at593nmwasdominant.Thus,thepreparedphosphorshowedremarkableluminescentpropertieswhichfindapplicationsinfieldemissiondisplay(FED)andplasmadisplaypanel(PDP)devices.

  • 标签: 钙钛矿结构 铕激活 荧光粉 光学特性 合成 扫描电子显微镜
  • 简介:Calciumtitanatedopedwithpraseodymiumwaspreparedthroughsolidstatereactionanditexhibitedintenseredemissionat612nm.Phosphorswerecharacterizedforphotoluminescence,thermo-luminescenceandafterglowemissions.Studyofeffectsofrareearthsonphotoluminescenceaswellasafterglowintensitywasreported.Presenceofgadoliniumenhancedluminescence.Presenceofsomemonovalentionsenhancedbothafterglowandphotoluminescenceemission.Thermo-luminescenceglowcurveswereanalyzedand...

  • 标签: perovskites 钙 titanates 红晚霞 稀土元素
  • 简介:在石灰窑大修过程中对石灰窑存在的薄弱环节采取了一些改进措施,建造新型石灰窑可以从根本上扭转公司石灰生产的被动局面。

  • 标签: 石灰窑 大修 窑体 耐火材料
  • 简介:Er~(3+)andLa~(3+)codopedY_2O_3nanocrystallinepowdersweresynthesizedbygelcombustionmethodandcharacterizedwiththermalanalysis,X-raydiffraction(XRD),transmissionelectronmicroscopy(TEM),high-resolutionTEM(HRTEM)techniquesandfluorescencespectroscopy.Afterbeingcalcinedat1200oC,the(Y_(1–x)La_x)_2O_3:Er~(3+)powderswereconfirmedtobecubicY_2O_3phasewiththecrystallinegrainsizeintherangeof20–40nm.TheEr~(3+)emissionat1.53μmfromthe~4I_(13/2)→~4I_(15/2)transitionwasobserved,whichwasfoundtobeenhancedbyintroducingLa~(3+)ions.SuchenhancementcouldbeattributedtotheadjustmentofEr~(3+)ions'localenvironmentbythecodopingofLa~(3+)ions,leadingtotheincreasedgroundstateabsorptioncrosssectionofEr~(3+)ions.

  • 标签: POWDERS IONS crystalline CALCINED attributed cubic
  • 简介:Duetotheremarkablemagnetoresistance(MR)effectonperovskite-typemanganite,magnetoelectronicsandspintronicshavebecomeattractivesubjectsofexperimentalandtheoreticalinvestigationsfortheapplicationpurpose.(La0.9Nd0.1)2/3Ca1/3Mn1-xFexO3(x=0,x=0.05)werepreparedsuccessfullybysol-gelmethod.Thestructure,magneticproperties,andtransportpropertiesofthecompoundswereinvestigated.Themagnetoresistanceeffectdependsonthecompositionandthetemperature.XRDpatternsshowthatthecompoundisasinglephasepolycrystalwithpseudocubicstructure.Alargenegativeisotropicmagnetoresistanceeffectinthesampleswereobservedatlowtemperatureregion.ThemaximumMRofthesampleswas77%and97%,respectively.Itwasmostlikelyduetothescatteringorthetunnelingtransportofspin-polarizedcarriersinlatticeunderstrongmagneticfield.

  • 标签: SOL-GEL method MAGNETORESISTANCE effect PEROVSKITE pseudocubic
  • 简介:InordertosensitizetheluminescenceofEu3+ionsinheavymetalglass,zincleadborateglasssamplescontainingvariousconcentrationsofEu3+andTb3+ionswerepreparedtostudytheTb3+toEu3+non-radiativeenergytransferphenomena.EnergylevelstructuresofTb3+andEu3+ionswereplottedtoshowtheexcitationandenergytransferroutes.EfficientenergytransferfromTb3+toEu3+wasobservedandstudiedqualitativelyintermsofdopingconcentrations.Thesensitizationturnedouttobelesseffectivethanexpected.FurtherstudiestocharacterizetheoxidationofTb3+intotetravalentstateandtoexaminethemechanismofenergytransferareproposed.

  • 标签: energy transfer ZINC LEAD BORATE glass
  • 简介:针对原燃料条件恶化,制定出各项合理的操作制度,使3#高炉各项技术指标大为改善,特别是节焦效果明显。

  • 标签: 3#高炉 操作制度 节焦
  • 简介:Eu3+/Sm3+codopedBiPO4黄磷与没有表面活化剂的环境经由一个灵巧的热水的方法被综合。X光检查衍射分析证明样品拥有了标准BiPO4单斜晶的结构。扫描电子显微镜学图象证明所有样品与像梭的形状分散得好的、测微计大小的晶体创作了。到Eu3+的从Sm3+的精力转移被光系列和Sm3+4G5/26H5/2排放的腐烂过程证实。橘子红光能在Eu3+/Sm3+codopedBiPO4黄磷被获得。Sm3+4G5/26H5/2排放的平均一生在BiPO4:0.03Sm3+在BiPO4:0.03Sm3+从2.70ms减少了到2.37ms,0.05Eu3+。在395nm附近的强壮、宽的吸收乐队,从Eu3+的7F05L6转变和Sm3+的6H5/24K11/2转变发源,资助BiPO4:Eu3+,有近紫外激动的white-light-emitting二极管的域里的潜在的应用程序的Sm3+黄磷。

  • 标签: 钐掺杂 水热合成 发光性能 X-射线衍射分析 白色发光二极管
  • 简介:目前工业制氧所使用的方法不近相同,采用的控制系统千差万别,仪表选型更是琳琅满目。基于以上原因,本文主要结合酒钢制氧的工艺特点,对DCS自控系统和仪表控制系统进行简单的分析。

  • 标签: 空气 制氧 DCS