简介:Inviewoftheimportanceofsolventextractionofrareearthmetalswiththeacidicorganophosphorousreagent,thedevelopmentofachemicallybasedmodelapplicabletohighconcentrationisdesired.Inthepresentstudy,theequilibriumdistributionofdysprosium(Ⅲ)betweenanaqueousnitricacidsolutionand2-ethylhexylphosphonicacidmono-2-ethylhexylester(PC88A)wasmeasuredintherangeofaninitialaqueousdysprosium(Ⅲ)concentrationfrom1.0×10-3to1.0×10-1kmol/m3andPC88Aconcentrationfrom0.16to0.65kmol/m3inShellsolD70asthediluent.Theobtaineddatawereanalyzedusingthechemicallybasedmodelinordertocorrelatetheequilibriumdistributionratios.Inthismodel,dysprosium(Ⅲ)wasassumedtobeextractedwiththePC88Adimerasa1:3complex,theactivitieswereconsideredfortheaqueousspecies,andtheeffectiveconcentrationofthePC88AdimerwascalculatedusingAlstad'sempiricalequation.Asaresult,theapparentextractionequilibriumconstantwasdeterminedtobe253(kmol·m-3)-2withanexcellentcorrelationbetweentheexperimentandcalculationresultsinthewiderangeofthelogarithmofthedistributionratiofrom-2to3.5.Inconclusion,themethodologyinthismodelwouldbeeffectiveforquantitativedescriptionofsolventextractionbehaviorofgeneralrareearthelementsaswellasdysprosium.
简介:采用扫描电镜、能谱仪以及X射线衍射仪对具有WC+β(β为钴基粘结相)两相结构的WC-11Co-0.71Cr3C2-0.06RE(RE为含La、Ce、Pr、Nd的混合稀土)硬质合金烧结体表面进行观察与分析。结果表明,在烧结过程中合金中的La、Ce、Pr、Nd通过定向迁移与烧结炉内气氛中的S、O等杂质元素结合,在合金烧结体表面形成RE2S3(主)和RE2O2S(少量)弥散相。从合金中Cr3C2的热力学稳定性、Cr在Co中的溶解度特性以及稀土原子激发等3个方面,对稀土迁移活性的激发机制和稀土原子的定向迁移机制进行分析与讨论。
简介:Byuseofmicro-DTAtechniqueaswellasambientandhightemperatureX-rayanalysisthephasediagramofNaCl-CaCl2hasbeenchecked.Itis.asimpleeutecticsystemwithasolidsolubilityinthesodiumchlorideside.Theeutecticpointisat773K,49mol%NaCl.Theexperimentalresults,especiallythoseoftheX-raydiffractionstudieshaveshowedthattheincongruentcompound4NaCl-CaCl2doesnotexistintheNaCl-CaCl2system.
简介:ThelongafterglowSrAl2O4:Dy,Euphosphorisliabletohydrolyzeinwaterwithdeteriorationoftheluminescentproperty.SrAl2O4:Dy,Euphosphorswerethereforeheatedat60-90℃inTEOSsoltoformasurfacegelandthenheat-treatedat400℃toobtainSiO2coatedphosphors.ObservationbyTransmissionElectronMicroscope(TEM)andX-rayphotoelectronspectroscopy(XPS)showsthatathinsilicafilmformsonthesurfaceofthephosphors.Thecoatingprocedurecanbeillustratedbyafour-stepprocessandthetransparentsilicafilmcansuppressthehydrolysisprocess,sothattheluminescentpropertiesofthephosphorsareunimpairedorevenbetter.
简介:研究纳米羟基磷灰石(HAP)涂覆的多孔Mg-2Zn(质量分数,%)支架材料的生物降解能力和生物相容性。采用脉冲电沉积制备羟基磷灰石涂层。对涂覆HAP的支架在碱性溶液中进行后处理来改善其生物降解性和生物相容性。研究支架和HAP涂层的显微组织和成分以及它们在模拟体液(SBF)中的降解和细胞毒性。经过碱溶液处理后的涂层由几乎垂直于基体的直径小于100nm的针状HAP组成,具有和天然骨头相似的成分,浸泡在SBF中后,产物为HAP、(Ca,Mg)3(PO4)2和Mg(OH)2。涂覆HAP和经过处理碱处理后的支架比未涂覆HAP的支架具有更高的生物相容性和细胞存活性。MG63细胞粘附在涂覆HAP和经过碱处理后的支架的表面并增殖,使这些支架有望应用于医学。结果表明:纳米HAP的脉冲电沉积和碱处理可有效改善多孔Mg-Zn支架的生物降解能力和生物相容性。
简介:InorganicbufferlayerssuchasSiO2orTiO2andtransparentconductiveindium-tin-oxide(ITO)filmswerepreparedonpolyethyleneterephthalate(PET)substratesbyionassisteddeposition(IAD)atroomtemperature,andtheeffectsofSiO2andTiO2onthebendingresistanceperformanceofflexibleITOfilmswereinvestigated.TheresultsshowthatITOfilmswithSiO2orTiO2bufferlayerhavebetterresistancestabilitiescomparedtooneswithoutthebufferlayerwhentheITOfilmsareinwardsbentatabendingradiusmorethan1.2cmandwhentheITOfilmsareoutwardsbentatabendingradiusfrom0.8cmto1.2cm.ITOfilmswithSiO2bufferlayerhavebetterresistancestabilitiescomparedtooneswithTiO2bufferlayeraftertheITOfilmsarebentseveralhundredsofcyclesatthesamebendingradius,fortheadhesionofSiO2isstrongerthanthatofTiO2.ThecompressivestressresultedfrominwardbendingleadstotheformationofmoredefectsintheITOfilmscomparedwiththetensilestressarisingfromoutwardbending.SiO2andTiO2bufferlayerscaneffectivelyimprovethecrystallinityofITOfilmsin(400),(440)directions.
简介:有5-8nm的尺寸的做Eu的GaOOHnanoparticles被热水的方法作为表面活化剂用钠dodecylbenzenesulfonate(SDBS)准备。做Eu的-Ga2O3和-Ga2O3被退火进一步制作GaOOH:Eu然后由X光检查衍射(XRD)描绘了,传播电子显微镜学(TEM)和光致发光(PL)。TEM结果显示出那monodisperse做Eu3+的GaOOHnanoparticles形式然后变换进通过退火的做Eu3+的-Ga2O3和-Ga2O3GaOOH:在600和900点的Eunanoparticles?????????????????@
简介:Inthiswork,asimpleandfacileone-potoleylaminesolvothermalsyntheticmethodwasdevelopedtosynthesizeCu_2ZnSnS_4(CZTS)nanocrystals.AndtheCu_2ZnSn(S,Se)_4(CZTSSe)thinfilmswerepreparedbyselenizingCZTSnanocrystals.TheobtainedCZTSnanocrystalsandCZTSSefilmswerestudiedusingX-raydiffraction(XRD),transmissionelectronmicroscopy(TEM),scanningelectronmicroscopy(SEM),energy-dispersiveX-rayspectroscopy(EDX),andultraviolet–visiblespectrophotometer(UV–Vis).TEMresultsshowthatthesphere–likeCZTSnanoparticleswithdiameterbetween12and35nmarepolydispersed.XRDstudiesindicatethatthepreparedCZTSnanocrystalsformkesteritecrystalstructure,andtheCZTSSefilmswithkesteritecrystalstructurearealsoobtainedattheannealingtemperaturesof500and550°C.Inparticularafterannealingat500°Cfor20min,theCZTSSefilmexhibitsasmooth,uniform,crack-free,andlarge-grainedtopographyandpossessesCu-poorandSn-richcomposition.Moreover,itshowsstrongopticalabsorptionfromvisibletonear-infrared(IR)region,anditsopticalbandgap(Eg)isfoundtobeabout1.44eV.
简介:Basedonclustervariationmethod(CVM)andnaturaliterationmethod(NIM),order-disorderphasetransitionintheintercalationcompoundsM1/2TiS2issimulatedbycomputer.Thefavorableconditions,underwhich3a0×a0superstructureisformed,aregiven,andtheresultsareingoodagreementwiththeexperimentsandtheoreticalcalculations.TherelationshipbetweencriticaltemperatureandM-ion-vacancyinteractionparameterislinear.