简介：采用自蔓延高温合成技术（SHS）制备固体氧化物燃料电池（SOFC）阴极材料La1-xSrxMnO3（LSM）;研究成形压力、稀释剂添加量等参数对反应过程及合成产物性能的影响;采用XRD、ICP研究SHS法合成LSM的物相和晶型结构.结果表明：自蔓延高温合成产物为钙钛矿结构菱方晶系La1-xSrxMnO3,Sr含量的变化引起合成产物特征峰的位置和半峰宽变化;随着Sr含量的增加,合成的LSM粉末粒度变细,晶格常数a和c减小.

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简介：对于x从0．0到0．4之间变化的Pt1-xSrxMnO3多晶体所进行的价带光电子能谱实验显示，在Fermi边和Fermi边以下－12eV范围内出现的能带态密度随掺杂量x有一个显著的变化。对这些现象以Pr1-xSrxMnO3体系在基态下发生电荷转移为出发点进行了讨论。提出了随掺杂量x的非线性电荷转移机制和存在由电荷转移导致的二级相变的可能性。

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.

简介：晶体结构和加氢行为(La_(1-x)Mg_x)_3Al(x=0.1，0.2，0.3，和0.4)合金被调查。这被发现有x=的合金0.1La和第0.2consi(Mg，艾尔)，La，和一个新奇阶段。新奇阶段作为La_2Al被决定。当Mg满足增加，La_2Al的数量减少，这被显示出。当x增加到0.3时，onlyLa(Mg，艾尔)并且La_2Al的小数量存在。当x是0.4时，La_2Al阶段消失，合金包含两La(Mg，艾尔)并且La(艾尔，Mg)_2洗阶段。(La_(0.9)Mg_(0.1))_3Al并且(La_(0.7)Mg_(0.3))_3Al合金能被氢的吸收在473K分解成LaH_3，MgH_2，和La_2Al_5。

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简介：ThemeasurementsoftemperaturedependenceofthemagneticsusceptibilityofLa1-xSrxCoO3perovskiteoxidesatdifferentSrdoping(0≤x≤0.5)andannealingtemperaturewerepresented.Forthesamplewithx=0.1,ashoulderwasobservedaround150K,andapeakwhichisonefeatureofspinglassappearedaround50Kinthecurveofsusceptibilityversustemperature.Thehigh-temperature(250～420K)susceptibilityfitswellwithCurie-Weisslawforallsamples.WeissconstantandeffectivemagneticmomentweredeterminedandtheirvariationswithSrdopingandoxygenannealingconditionwereobtained.TheWeissconstantincreasesmonotonouslywithSrcontentforx>0.2.Thevaluesofeffectivemomentswereinterpretedwiththespinstateofcobaltions.Studiesonthesusceptibilitiesofthesampleswithx=0.2underdifferentpreparationtemperaturesandannealingtemperaturesshowthattherisingofsinteringtemperatureandannealingtemperaturewillincreasethepara-ferromagnetictransitiontemperature,andreducetheeffectivemomenttonormalvalue.OurresultshowsthatbothCo3+andCo4+ionsshouldbeinISstateafterannealingandtheoxygenannealingcausesthetransitionofCo3+spinstatefromHStoIS.

简介：采用溶胶-凝胶法制备了La1-xBaxCoO3（0≤X≤0．35）电极材料，系统研究了材料的微结构和电输运性能．研究表明，Ba掺杂的样品生长较好且符合理想的化学配比；当X〈0．3时，材料的晶格结构没有改变，当X≥0．3时，材料发生结构相变，由菱方晶系转变为立方晶系；当Ba的掺杂量达到0．3时，样品由半导体向金属转变，Ba掺杂提高了LaCoO3电导率和在氧化环境下的稳定性，这一特点使其在阴极材料中具有潜在的应用前景．

简介：ThetransportpropertiesintheLa2/3(Ca1-xSrx)1/3MnO3(x=0,1/3,2/3)filmspreparedusingtheRFmagnetronsputteringmethodwereinvestigated.TheeffectoftheCa,Srdouble-dopingattheApositionintheLa2/3A1/3MnO3onthestructureofthetargetsandtransportofthefilmshasbeenstudied.Withtheincreaseofx,thestructuresofthetargetstransformfromtherhombohedralphasetothecubicphase;themetal-insulatorphasetransitiontemperature(Tp)ofthefilmsincreases;andthecorrespondingpeakresistivitydecreases.Allthephenomenacanbequalitativelyexplainedbythelatticeeffect.

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简介：Inordertorealizetheco-firingwithAg/Pdelectrodesinmultilayerdevices,Pb(Zn1/3Nb2/3)1-,-yZrxTiyO3(0.25＜x＜0.35,0.25＜y＜0.35)piezoelectricceramics(hereafterdesignatedPZN-PZT)modifiedbyLa2O3hasbeenpreparedbyconventionaltechniquewithsinteringtemperaturefrom1100℃to1140℃.X-raydiffractionpatternsdemonstratedthatpureperovskitephasewasobtained.Secondaryelectronimage(SEI)showedthatcrystallinegrainsinceramicswerewellgrown.d33ofmanufacturedsamplewasashighas560×10-12C/N.kpwasabout0.61andtgδabout30×10-3.TheexistenceofliquidphaseexaminedbyelectrondiffractioninPZN-PZTsampleisbeneficialtosinteringoftheceramic.

简介：［1］S.Jin,T.H.Tiefel,M.McCormack,etal.:Sci-ence,264(1994),p.413.［2］R.vonHelmolt,J.Wecker,B.Holzapfel,etal.:Phys.Rev.Lett.,71(1993),p.2331.［3］Y.Shimakawa,Y.Kubo,T.Manako:Nature,379(1996),p.53.［4］C.Zener:Phys.Rev.,82(1951),p.403.［5］A.J.Millis,P.B.Littlewood,B.I.Shraiman:Phys.Rev.Lett.,74(1995),p.5144.［6］A.J.Millis,B.I.Shraiman,R.Mueller:Phys.Rev.Lett.,77(1996),p.175.［7］D.Louca,T.Egami,E.L.Brosha,:Phys.Rev.B,56(1997),p.8475.［8］G.Zhao,K.Conder,H.Keller,etal.:Nuture,381(1996),p.676.［9］C.H.Booth,F.Bridges,G.J.Snyder,etal:Phys.Rev.B,54(1996),p.15606.［10］K.H.Kim,J.Y.Gu,H.S.Choi,etal.:Phys.Rev.Lett.,77(1996),p.1877.［11］S.Zhou,G.Zhou,Y.Zhang:Jpn.J.Appl.Phys.,38(1999),p.5075.［12］S.Tajima,A.Masaki,S.Uchida,etal.:J.Phy.C:SolidStatePhys.,20(1987),p.3469.［13］L.M.Rodriguez-Martinez,J.P.Attfield:Phys.Rev.B,58(1998),p.2426.

简介：PolycrystallinesamplesofLa12x(Sr12yAgy)xMnO3(y=0.0,0.2,0.4,0.6,1.0)werepreparedbythesolid-statereactionmethod.ThetemperaturestabilityofmagnetoresistanceandmagnetoresistanceenhancementinLa1-x(Sr1-yAgy)xMnO3systemwithbothunivalentandbivalentelementsdopedatAsiteandwithunchangedvalueofMn3+/Mn4+ratiowereexploredthroughthemeasurementsofX-raydiffractionpatterns,magnetiza-tion-temperature(M-T)curves,resistivity-temperature(q-T)curvesandmagnetoresistance-temperature(MR-T)curves.Theresultsareasfollows:therearetwopeaksintheq-TcurvesofthesampleswithAgdoping,oneiscausedbyresistancechangeduringtheparamagnetism-ferromagnetismtransition,andtheotherisfromboundary-dependentscatteringofconductionelectronsontheboundariesofgrains.ThepeakvalueofMRincreaseswithincreasingAgdopingcontent,anditincreasesfrom8.2%fory=0.2to29.6%fory=1.0underthemagneticfieldofB=0.8T;MRremainsaconstantof12%inthetemperaturerangeof218-168Kforthesamplewithy=1.0,andthetemperaturestabilityofMRisinfavorofthepracticalapplicationofMR.

简介：本文通过高分辨X射线衍射及掠入射(GID)的实验方法对生长在SrTiO3衬底上的LLa2/3Ca1/3MnO3和YBaCu3O7单层膜及YBa2Cu3O7-x/La2／3Ca1／3MnO3异质结构双层薄膜的微结构进行了研究。结果发现，所有薄膜都呈c向生长。由于热膨胀系数的不同而引起的热应力使得LCMO膜的晶格参数与靶材的相差较大。La2/3Ca1/3MnO3在单层腹及双层膜中都由靶材的立方结构变成了薄膜状态的四方结构。YBa2Cu3O7在单层膜及双层膜中都由靶材的正交结构变成了薄膜状态的四方结构。La2/3Ca1/3MnO3膜与YBa2Cu3O7膜在不同的样品中处于不同的应力状态。

简介：TheLa3+-loadedadsorbentwaspreparedbythereactionbetweenLa3+andethanolamine-modifiedvegetabletannicextract,totreatF--containingwastewater.TheproblemsofheavycolorcausedbyvegetabletannicextractandofturbiditycausedbyreactionbetweenLa3+andF-weresolved.Whenotherconditionswerenotchanged,pH,temperature,stirringtime,anddosewerechangedrespectivelyandtheadsorbancewastestedrespectively.Theresultsshowthatthisadsorbentpossesseshighsaturatedadsorptivecapacity(18.86mg·g-1)whenpHis5～6,T≤80℃,0.2gdosage,and180minagitatingtime,andtheadsorbancereachesthehighest(98.5%).Theadsorbentcanbeeasilyregeneratedwith0.5mol·L-1NaOHatpH12.

简介：以La（NO3）3·nH2O、Pr（NO3）3·6H2O、Ni（NO3）3·6H2O为原料，丙氨酸为分散剂，采用低温燃烧法合成了（x=0．1～0．9）系列钙钛矿型复合氧化物。用TGDSC、XRD、TPR、SEM等表征手段对样品进行表征。结果表明，La0.5Pr0.5NiO3在650℃开始形成稳定的钙钛矿结构，焙烧800℃时，表面晶粒均匀；随着Pr的取代度增大，Pr离子未能完全进入LaNiO3晶格中A位，以氧化物的形式存在于钙钛矿晶体表面，同时La1-xPrxNiO3表面存在两种不同活性的氧物种，缺陷氧结构数量随着取代度的增大而增大。

简介：用溶胶-凝胶法制备了系列掺杂（La0.8Ln0.2）2/3Ca1/3MnO3（Ln=La，Ce，Pr，Nd，Sm，Eu）纳米级晶体。对比在La被其它镧系元素部分替代后，引起的A位离子平均半径的改变和磁矩变化对电输运及磁阻性能的影响，实验分析表明，各个样品在同样大小磁场下的磁电阻存在较大的差别，样品的磁电阻随原子序数的增加而明显变大，由镧系收缩引起晶格畸变所产生的本征磁电阻占主导地位，随着外加磁场的增加，不同掺杂样品间的峰值电阻差异被弱化；各掺杂样品间的转变温度差与掺杂离子半径差和磁矩差密切相关，且离子半径的差异对转变温度的改变贡献更大。

简介：Perovskite-typeLa1-xCexMnO3（x=0-10%）catalystswerepreparedbyflamespraypyrolysisandtheiractivitiesduringthecatalyticoxidationofbenzenewereexaminedoverthetemperaturerangeof100-450℃.ThestructuralpropertiesandreducibilityofthesematerialswerealsocharacterizedbyX-raydiffraction（XRD）,N2adsorption/desorption,H2temperature-programmedreduction（H2-TPR）andX-rayphotoelectronspectroscopy（XPS）.TheincorporationofCewasfoundtoimprovethebenzeneoxidationactivity,andtheperovskiteinwhichxwas0.1exhibitedthehighestactivity.Phasecompositionandsurfaceelementalanalysesindicatedthatnon-stoichiometriccompoundswerepresent.TheincorporationofCehadanegligibleeffectonthespecificsurfaceareaoftheperovskitesandhencethisfactorhaslittleimpactonthecatalyticactivity.IntroductionofCe44+resultedinmodificationofthechemicalstatesofbothB-siteionsandoxygenspeciesandfacilitatedthereducibilityoftheperovskite.ThesurfaceMn4+/Mn3+ratiowasincreasedasaresultofCe4+substitution,whileadecreaseinthesurface-adsorbedO/latticeO(Oads/Olatt)ratiowasobserved.Therelationshipbetweenthesurfaceelementalratiosandcatalyticactivitywasestablishedtoallowabetterunderstandingoftheprocessbywhichbenzeneisoxidizedoverperovskites.

简介：介绍了在液相中连续生产１，１，１，３，３，３，－六氟丙烷（ＨＦＣ２３６ｆａ）和／或１－氯－１，１，３，３，３－五氟内烷（ＨＣＦＣ２３５ｆａ）的工艺，反应中使用ＨＣＦＣ－２３５ｆａ和／或ＨＦＣ２３６ｆａ作为溶剂。当反应是在ＳｂＦ３、ＳｂＦ５或ＳｂＦ５和ＨＳＯ３Ｆ的混合物催化剂存在下进行时，反应物料对所用容器的腐蚀非常低。