简介:有核心壳的合成nanoparticles组织的Cross-linked-cyclodextrinpolymer/Fe3O4在carboxymethyl-cyclodextrin的表面上经由生气连接反应被准备(厘米--CD)在-cyclodextrin的修改Fe3O4nanoparticles由把epichlorohydrin用作crosslinking的碱的答案代理人。准备合成nanoparticles的形态学,结构和磁性被传播电子显微镜学(TEM)调查,Fourier变换红外线(FTIR)spectrometry,X光检查衍射(XRD)测量,thermogravimetric分析(TGA)和颤动的样品magnetometry(VSM)分别地。
简介:Fe2O3nanoparticlescoatedwithsodiumdodecylbenzenesulphonate(DBS)orcetyltrimethylammoniumbromide(CTAB)werepreparedbyusingamicroemulsionmethodinthesystemwater/toluene.Thenanoparticleswerecharacterizedbymeansoftransmissionelectronmicroscopyandaverageparticlesizesof5.0nmand6.0nmwerefoundforDBS-modifiedandCTAB-modifiednanoparticlesrespectively.Thelocalatomicstructuresoftheseiron(Ⅲ)oxidenanoparticleswereprobedbyusingtheextendedx-rayabsorptionfine-structuretechnique.FeKabsorptionspectrawerecollectedatbeamline4W1BofBeijingSynchrotronRadiationFacility.Astructurealmodelwasproposedfordescribingtheiratomicstructures.TheFe-ObondlengthatthesurfaceofDBS-coatedFe2O3nanoparticleswasfoundtobesimilartothatinbulkFe2O3.buttherewasabout0.04AexpansionfortheCTAB-coatedFe2O3nanoparticles.Onthebasisofthemodelproposedinthispaper,thethicknessesofthesurfacelayerswereestimatedtobe0.5nmand0.7nm.respectively,fortheDBS-coatedandCTAB-coatedFe2O3nanoparticles.Theanharmonicityoftheatomicvibrationandtheasymmetryofatom-pairdistributionwerefoundtobelargeratthesurfaceofthenanoparticlesthaninthebulkmaterial,whiletheDebye-Wallerfactorsarealmostthesameforthesurfaceandthecorepartsofthenanoparticles.Itcanbeconcludedthattheatomicstructureofthenanoparticlesurfaceisordered.buttheatom-paridistributionisasymmetric.
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简介:ThispaperintroducesabrazingprocessbetweenAl_2O_3ceramicandInvaralloy.Al_2O_3canbebrazedwithInvareffectively.TheinterfacialstructureofAl_2O_3/Invarjointcanbeexpressedas:Invar/Ag(s,s)+Cu(s,s)+Fe_2Ti(zoneⅠ)/Ag(s,s)+Cu(s,s)+Fe_2Ti+NiTi+Cu_3Ti(zoneⅡ)/Ag(s,s)+Cu(s,s)+Cu_2Ti+Al(s,s)+TiC+TiO(zoneⅢ)/Al_2O_3.Themaximumshearstrengthof139MPawasmeasuredforas-brazedAl_2O_3/Invarjointbrazedat850℃for25minor900℃for15min.
简介:NewrareearthvanadatesYSrQ-xCaxV3O9-y(x=0.0,0.67,1.0,1.33and2.0)havebeensynthesizedbyanewsimplemethod.X-raypowderdiffractionresultsshowthattheyaremono-phase.Theybelongtoorthorhombicstructureandtheirlatticeconstantsarecalculated.TheresultsofweightgainsinTGcurvesshowthatthelowervalentvanadiumisoxidizedtohighervalentstateathighertemperature.Theoxygencontentsofnewcompoundsarecalculatedfromtheweightgains.BothV3+andV4+coexistinYSr2-xCaxV3O9-y.Thesecompoundsexhibitlowelectricresistivityatroomtemperature.
简介:ScanningElectronMicroscopyStudiesofYBa_2Cu_3O_(7-δ)SuperconductorsShaWei(沙维)(DepartmentofCivilEngineering,TheQueen′sUniversit...
简介:TheinfluenceofthreedifferentAl2O3powderonself-flowingaluminacastablewasstudied.MaximumcompactionofsamplewascomputedbyAndresenEquation.TheresultshowedthattheAl2O3powder,whichhasmuchsmallerparticlesize,couldimprovethemicrostructureandthemechanicalpropertiesofcastableunderroomtemperatureandhightemperature.Withthesamepowdersize,theroomtemperaturestrengthofthecastableaddedwithAl2O3powderproPertiesofwhichwerealteredbyaddingmineralizingagent,washigherthanthatofthecastableaddedwithcommonAl2O3powder,buttheflowabilityofthesethreedifferentcastablewasalmostthesame.
简介:摘要:作为一种新兴的超宽带隙半导体,氧化镓(Ga2O3)受到了广泛的关注。高质量的块状晶体和薄膜是结构、电学和光学特性的基础研究和进一步器件制造的起点,为了实现高性能的Ga2O3基器件,必须通过控制载流子密度、缺陷密度和界面密度来制备高质量的Ga2O3薄膜和单晶。在本文中,我们将简要概述大块单晶合成以及不同外延生长技术的特性和研究进展, 并指出了目前研究中存在的困难和挑战。
简介:SlagcorrosionresistanceofMgOZrO2refractorieswasinvestigatedinthiswork.Theresultsindicatethatinanon-orientedelectricsteelslagsystemwithahighratioofcalciatosilica,theslagresistanceofMgOZrO2refractoriescanbedescribedasfollows:ZrO2reactswithCaOformingcalciumzirconatecompoundwhichstrengthensthematerialandblocksthechanneloftheslaginfiltration;however,inanorientedelectricsteelslagsystemwithahighconcentrationofsilicaandthelowratioofcalciatosilica,theslagcorrosionresistanceofMgOZrO2refractoriesisdifferent;ZrO2reactswithCaOformingthecalciumzirconateandsimultaneouslyonemoreproductC2Saswell;C2Scanimprovecorrosionresistancebyblindingporeandenhancingslagviscosity;therefore,itisexpectedtobethemajorreasonfortheenhancedcorrosionresistanceobservedforMgOZrO2refractories.
简介:一篇小说荧光灯为H2PO4-基于碳dots/Fe3+被设计并且制作合成。碳点被一个确定的一个壶综合热水的方法并且由传播电子显微镜,X光检查衍射计,紫外力的吸收分光计和荧光分光光度计描绘了。碳dots/Fe3+合成被碳点和FeCl3,的水的混合获得,它的荧光性质被荧光分光光度计描绘。碳点的荧光被水的Fe3+阳离子熄灭,导致碳dots/Fe3+的低荧光紧张合成。在另一方面,H2PO4-由化学反应减少了Fe3+的集中并且提高了碳dots/Fe3+的荧光合成。Stern-Volmer方程被介绍描述在合成的碳dots/Fe3+和H2PO4-,和好线性(R2=0.997)在H20.4-12公里的PO4-集中。
简介:本文研究了以TiO2-Sb2O3/SO4^2-为催化剂,催化假性紫罗兰酮合成紫罗兰酮。探索了反应温度、反应时间、催化剂用量、溶剂用量等因素对环化反应的影响。最佳合成条件:6mL假性紫罗兰酮,催化剂用量为1.8g,溶剂用量为6mL,环化反应温度为30℃,反应时间为3.0h,紫罗兰酮产率约为70%。