简介：Oxidationprocessoflanthanumhexaboride(LaB6)ceramicpowderwasinvestigated.TheLaB6powdersampleswereheatedcontinuallyfromroomtemperatureto1473Kataheatingrateof10K/minbydifferentialscanningcalorimetry.Theoxidationtestswereconductedatdifferentexposuretemperatures.ThephasesandmorphologiesofthesamplesbeforeandafterexposurewereanalyzedbyXRDandSEM.Itwaspointedoutthatbefore1273K,LaB6hashighoxidationresistantability,whichwasduetothattheoxidelayerhinderstheoxygendiffusionfromoutertothesurfaceofLaB6grains.Theoxidelayerwascomposedofthetransitionphases,whichwerecomposedofLa2O3andB2O3formedfromtheinitialoxidation;whentheoxidationtemperatureexceeded1273K,protectivelayerwasdestroyedduetothevaporizationofliquidB2O3.BasedontheresultsofX-raydiffractionanalysis,oxidationprocessofLaB6ceramicpowdercanbedescribedasfollows:Before1273K,lanthanumborate，La(BO2)3wasformedonthesurfaceofsamples,thenlanthanumoxide(La2O3)andboronoxide(B2O3)werepresentonthesurfaceofsamplesoxidizedwhenthetemperaturereachedto1473K.

简介：YoungWistarratsweredividedintosixgroups,theexperimentalgroupsweregivenLa(NO3)3atdoseof20,10,2,0.2,0.1mg*kg-1andthecontrolgroupwasgivenphysiologicalsalinerespectivelyforsixmonths.Theanimalswereweighedandtheratiosofthelivertobodyweightwerecounted.Pathologicalchangesofliverwereobservedbylightmicroscopeandtransmissionelectronmicroscope.Glutamic-oxalacetictransaminase(GOT),glutamic-pyruvictransaminase(GPT),gamma-glutamyltransferase(γ-GT)andalklinephosphatase(ALP)intheserumweremeasured.Theresultsindicatethatthebodyweightofanimalsgainesslowlyinthegroupof20mg*kg-1La(NO3)3,butitgainedquicklyintheratsfedwith0.1mg*kg-1La(NO3)3.Biochemicalindexeshavenoabnormalchanges.Inthegroupof20mg*kg-1La(NO3)3,therewerelipiddropletsanddecreaseofglycogeninthehepatocytes,densermatrixofthemitochondria,deformationofthenucleiofsomehepatocytestodifferentdegreeandinfiltrationofinflammatorycellsatportalarea.ThemorethedoseofLa(NO3)3weregiventotherats,themorethenumberofbodiescontaininghighlyelectronicdensegravel-likegranulesandthesecondarylysosomeswithdensebodies.Theratsfedwith20mg*kg-1La(NO3)3forsixmonthsshowsinjuriouseffectsonthehepatocytes.

简介：LowcostsiliconcarbonnanometerpowderwassynthesizedbycarbothermalreductionmethodwithnanometerSiO2andcarbonasrawmaterial.Itssynthesisthermodynamicswerediscussed.TheinfluenceofLaonTG-DSCcurvewasalsoanalyzed.ItindicatedthatthesynthesisprocessofSiCpowderhadtwosteps.InthefirststeptwomedialproductionsofSiOgandCOgformed,andinthesecondstep,β-SiCwasfinallysynthesized.After0.3%Laadded,atthefirststep,theinitiatoryformingtemperatureofproducingSiO(g)andCO(g)declinedfrom1351.4to1250.9℃,andthethermalactivationenergydecreasedfrom223.6to34.7J·g-1;atthesecondsteptheinitiatoryformingtemperatureofsynthesizingβ-SiCpowderdeclinedfrom1526.5to1357.8℃,andthethermalactivationenergydecreasedfrom693.7to295.7J·g-1.WithoutLaadded,thebestsynthesistechnologyforβ-SiCpowderwas1550℃for120min,averagepowderdiameterwasbiggerabout150nm.WithLaadded,thebestsynthesistechnologywas1500℃for120min,averagepowderdiameterwasabout100nm.

简介：Theprocessesreportedforthepreparationoflanthanumhexaboride(LaB6)fromlanthanumoxideinvolvetheuseofcarboneitherelementalorintheformofboroncarbideorelementalboronitselfasreducingagents,fusedsaltsathightemperaturesorreactionswhichrequiretheproductboridetobeleachedout.Eachofthesetechniqueseitherincreasestheprocesscostsand/orincreaseschancesofcontaminationinfi-nalproduct.PureLaB6canbestbepreparedbyareactionwhichproducesagaseousbyprodu...

简介：TheeffectsofLaonsomehydrolyticenzymeactivitiesinredsoilwerestudiedinincubationandpetcultureexperiments.Intheincubationexperiment,Laslightlystimulatestheactivitiesofureaseandacidicphosphataseinsoilandstronglystimulatessucraseactivityinsoil.Inthepetcultureexperiment,Lastimulatestheactivitiesofurease,acidicphosphataseandsucrasetodifferentdegrees.Thestimulativeeffectsofrareearthelements(REE)onhydrolyticenzymeactivitiesinsoilmayresultinincreasingyieldofeivps.

简介：TheinfluencesofMediumpH,sorptiontemperature,sorptiontime,etc.onthesorptioncapacityofmacroporousphosphonicacidresinforLa^3+weredetermined.Thesorptionrateconstantwask298=7.64×10^-5s^-1.ThecomplexratioofphosphonicgroupsoftheresintoLa^3+was3:1.Thebasicsorptionparametersweredetermined.ThesorptionmechanismofmacroporousphosphonicacidresinforLa^3+wasexaminedbychemicalanalysisandIR-spectrometry.

简介：ＳｔｕｄｉｅｓｏｎＥｌｅｃｔｒｏｌｙｔｉｃＣｏｄｅｐｏｓｉｔｉｏｎｏｆＬａｎｔｈａｎｕｍ－ＣｏｂａｌｔｉｎＵｒｅａＭｅｌｔＱｉｕＫａｉｒｏｎｇ（丘开容），ＹａｎｇＱｉｑｉｎ（杨绮琴）（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＺｈｏｎｇｓｈａｎＵｎ...

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简介：macroporous的吸着性质为La3+离子的弱酸树脂(D113)被化学分析和红外系列学习。试验性的结果显示D113树脂在pH=为La3+有一个好吸附能力6.0在HAc-NaAc媒介。静态地浸透的吸附能力是273.3mg/g。La3+/Ce3+，La3+/Gd3+，La3+/Er3+，和La3+/Y3+的分离系数分别地是2.29，3.64，4.27，和0.627。吸附的明显的激活精力，Ea是吸着的18.4kJ/mol，热力学参数H，S，和G是4.53kJ/mol，61.8J/(mol.K)，?13.9kJ/mol分别地。为La3+的D113的吸附行为服从Freundlich等温线。在树脂上吸附的La3+能是由2.0mol/LHCl份量上的eluted。

简介：Theeffectoflanthanumiononmembranepermeabilityofcornrootsegmentisstudied.ResultsshowsthattreatmentoftherootsegmentswithLaCl3·7H2Ocandecreasetheionleakageoftheroottissue.Theleakagedecreaseshyincreasingtheconcentrationoflanthanum,andtheconcentrationhasnofurtherdependenceonionleakagesabove25μmol/L.Aftertreatingtheroottissueforonehourwithlanthanumion,theamountofleak-agehaslineardependenceontimewithinthefirst2handaftertwohourstheleakageincreases.Theionleakageofthetissuedependesonthetimeoflanthanumtreatment.Whenthedurationoftreatmentisprolonged,theleakagedecreasesrapidlyandtheleakagereachesaminimumat30minutes.Otherrareearthelementscanalsodecreaseionleakage.Thereisnosignificantdifferenceintheionleakageamongtheseelements.

简介：TheelectrochemicalbehaviourofcopperelectrodeinmoltenNaCl-KCl-LaCl3hasbeeninvestigated.TheLa-CualloyisformedatfirstandthenthemetalliclanthanumisdepositedwhentheLa3+isreducedonthecopperelectrode.ThetechnologicalconditionsofpreparingLa-Cualloybyconsumablecathodehavebeendis-cussed.TheLa-Cualloycontainedlanthanumover90wt%wasobtained.ThecompositionofalloywasLaCu2andLa.Thecurrentefficiencywas85%andtherecoveryoflanthanumwasnear90%.

简介：Theheatcapacitiesofthetwocomplexes,[La2(Gly)6(H2O)4]·(ClO4)6and[Ho2(Gly)6(H2O)4](ClO4)6·2H2O(Gly=glycine),weremeasuredbyadiabaticcalorimetryinthetemperaturerangeform78to375K.Asolid-solidphasetransitionwasfoundbetween322.87and342.29Kfor[Ho2(Gly)6(H2O)4](ClO4)6·2H2O,andthepeaktemperature,theenthalpyandtehentropyofthetransitionwereobtainedtobe330.94K,11.65kJ·mol^-1and35.20J·K^-1·mol^-1,respectively.Noindicationofanyphaestransitionorthermalanomalywasobservedfor[La2(gly)6(H2O)4](ClO4)6,Thermalstabilitiesofthetwocomplexeswereinvestigatedbythermogravimetryinthetemperaturerangeof40-800℃.thepossiblemechanismsforthethermaldecompositionswereproosedaccordingtotheTGandDTGcurves.

简介：ThroughapotculturelanthanumnitratewasappliedtomaizeseedlingsgrowninaredloamysoiltoinvestigatethephysiologicalandtoxiceffectsofaddedLaonthegrowthofcropseedlingsandLabioaccumulationtohelpunderstandtheenvironmentalchemistrybehaviorsofrareearthelementasfertilizersinsoils.Comparedtothecontrol,LaconcentrationsinshootsandespeciallyinrootsofmaizeseedlingsincreasedwithanincreaseofLainthesoil.Also,withaddedconcentrationsofLa≥0.75gLakg-1soiland≥0.05gLakg-1soil,thedryweightofshootsandrootsofmaizeseedlingswassignificantlyreduced(P≤0.05),respectively,comparedwiththecontrol.Additionally,La≥0.5gkg-1inthesoilsignificantlyinhibited(P≤0.05)primaryrootelongation.RootsweremoresensitivetoLastressthanshootsandthuscouldbeusedasabiomarkertoLastress.Overall,intheredloamysoilstudied,LahadnosignificantbeneficialeffectsonthegrowthofmaizeattheaddedLalevelsabove0.1gkg-1soil.

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.

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简介：ViciafabaL。幼苗水耕法地在体外的镧(La)的012mg/L被栽培让15d调查ecotoxicological效果并且冒险对稀土元素元素(REE)的评价。结果显示出象superoxide基那样的那反应的氧种类(ROS)生产(O2吗？？

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简介：AZ31上的血浆电解氧化(PEO)涂层镁(Mg)合金作为一个基础电解质系统与碱的硅酸盐和钠氢氧化物用水的解决方案被开发。铈(Ce)的效果硝酸盐和镧(La)电压反应，微观结构，作文和PEO涂层的腐蚀电阻上的硝酸盐添加剂被扫描电子调查显微镜学(SEM)，精力散的光谱(版本)，X光检查衍射(XRD)和potentiodynamic极化测试，等等。结果证明Ce和La添加剂增加了PEO涂层的稳定的电压和紧密，当时，那些没改变PEO涂层的作文。与0.1g/L的La硝酸盐在答案获得的PEO涂层的腐蚀电阻是最好，没有添加剂，与0.1g/L和那的Ce硝酸盐由那列在后面。

简介：Studieshavebeencarriedoutontheeffectoflanthanum-aminoacidcomplexesonembryodevelopmentandnaupliusgrowthofPenaeuschinensis.Theexperimentalresultsindicatethat:(1)Theoptimumconcentrationsoflanthanum-prolineandLanthanumphenylalanineforthedevelopmentofeggsinmonocellanddicellstagesare1.50～4.00mg/Land0.50～3.00mg/L,respectively,theegghatchingratesbeingraisedby21.0～46.0%and23.0～42.8%(P＜0.05)respectively.(2)Theoptimumconcentrationsoflanthanum-prolinecomplexandLanthanum-phenylalaninecomplexforthegrowthofnaupliiare1.50～4.00mg/Land0.50～3.00mg/L,themetamorphosisratefromnaupliustoprotozoeabeingraisedby16.4～27.5%and20.4～26.7%(P＜0.05)respectively.(3)Thepositiveeffectoflanthanum-aminoacidcomplexesonegghatchingandnaupliusmetamorphosisofPenaeuschinensisisbetterthanthatoflanthanum.Withregardtothepositiveeffect,lanthanum-prolinecomplexisbetterthanLanthanum-phenylalaninecomplex.