学科分类
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16 个结果
  • 简介:Themainlycharacteristicoftrappingmaterialsisthetrapdepth.Soitissignificanttocalculatethetrapdepthforthetrappingmaterials.Anewmethodofcalculatingtrapdepth,whichisbasedonenergybandandusingrateequationstoanalyzethermoluminescence,wasbroughtforward.Thismethodwhichusestherateequationsoftheprocessandthethermoluminescencecurvecanreplacetraditionalmethodssuchasfirstorderorsecondorderkinetics.ThetrapdepthofSrAl2O4:Eu2+,Dy3+andSr4Al14O25:Eu2+,Dy3+wasestimatedfromtheglowcurve.Thenthenumevicalsolutionofthetrapdepthcanbeobtained.Fromtheresultsofexperimentsandcalculations,thismethodcanaccuratelyindicatethewholeprocess.

  • 标签: 稀土 热发光 发光动力学 陷阱深度 计算方法
  • 简介:Rareearthcompoundsasmodifiersusedwidelyinmodernfrictionmaterialscanenhancetheinterfacialbindingofconstituentsofmaterialsandimprovethecomprehensivepropertiesofmaterialsevidently.However,therearestillfewreportsonapplicationofrareearthinautomotivefrictionmaterials.Inordertostudytheeffectmechanismofrareearthsinfrictionmaterials,arareearthcompoundwasselectedasadditiveandtheeffectsofmaterialsdopedwithorwithoutrareearthonfrictionandwearpropertiesofmaterialswerestudied.Themicrostructureandwornsurfacemorphologywereobservedbyscanningelectronmicroscopyandthemacroperformancewasdiscussed.Wornsurfaceelementconstitutionofmaterialswasanalyzedbyenergydispersivespectroscopy.Effectmechanismofrareearthsonfrictionandwearbehaviorsoffrictionmaterialswerediscussed.Theresultsshowthatdopingrareearthsinfrictionmaterialscanstabilizefrictioncoefficient,lowerthewearrateofmaterialsandincreasetheimpactstrengthofmaterials.Theflexibilityandfractureresistanceofmaterialsisgreatlyimproved.Wornsurfaceofmaterialsdopedwithrareearthiscompactandthesurfaceadhesionisgreatlyenhanced.

  • 标签: FRICTION materials PROPERTIES MICROSTRUCTURE effect mechanism
  • 简介:Additionofrareearth(RE)suchasYinthesurfacelayerofgraycastironorNi-basedsuperalloybylasersutfacemeltingwascarriedoutusinga2kWCO2laser.FordeliveringtheelementYtothemetalsurfacedur-inglaserirradiation,severalmethodswereemployed.ItisfoundthatY-containingsurfacemodifiedlayercanhecontrollablyobtainedonsubstrates,agraycastironcanbelasersurface-modifiedwithCr+Al-Ypowderre-sultinginathinlayerofFe-Cr-Al-Yalloysuchas30Fe40Cr27Al3Y.

  • 标签: SURFACE MODIFICATION LASER ALLOYING YTTRIUM
  • 简介:混合稀土元素元素被合并到氧化铝陶器的材料。Hot-pressing被用来在氮空气保护制作氧化铝矩阵composites。微观结构和composites的机械性质被测试。这被显示氧化铝矩阵的弯曲力量和破裂坚韧在1550点的陶器的compositessintered吗??

  • 标签: 非金属材料 无机物 氧化铝 矾土 稀土
  • 简介:Theresincompositematerials(RCM)werepreparedbythemethodofdopingresinwithtourmalinepowdersmodifiedwithlanthanumelement.Itwascharacterizedbyscanningelectronmicroscope(SEM),IRradiationdetermination,X-raydiffraction(XRD),andfouriertransforminfraredspectroscope(FTIR).TheresultsshowedthattheRCMcouldradiatehigherintensityoffarinfrared.Themolecularmovementwasstrengthenedandtheinter-molecularcontactswereeasilyreducedwhenthedieseloilwasdealtwiththeRCM.TheeffectsoftheRCMontheoilconsumptionandairpollutantemissionsofoil-burningboilerwereinvestigated.Theoil-savingrateoftheRBS·VH-1.5boilerdealtwiththeRCMwas2.76%,andthereducingratesofCOandNOintheexhaustgaswere32.9%and15.8%,respectively.

  • 标签: LANTHANUM element resin composite MATERIALS TOURMALINE
  • 简介:Thenanosizedparticlematerialsofdoped-TiO2withY2O3werepreparedbymeansofsol-geltechniqueforuseinelectrorheological(ER)fluids,andtheircrystalstructuresweremeasuredbyX-raydiffraction(XRD)analysis.TocomparewiththepureTiO2,adistinctenhancementintheshearstressunderdcelectricfieldwasfoundbyusingsuchmaterials.Thiscanbeexplainedbytheincreaseofthedielectriclossanddielectricconstantatlowfrequency.TheeffectsofthecrystalstructureoftheparticlesonthedielectricpropertyandERperformanceofmaterialswereinvestigated.

  • 标签: 二氧化钛 纳米材料 掺杂 稀土 XRD 结构
  • 简介:La1.5Mg17Ni0.5hydrogenstoragematerialswerepreparedbyhydridingcombustionsynthesis(HCS)andmechanicalalloying(MA)methodrespectively.TheexperimentalresultsshowthatthehydrogenabsorptionpropertiesofLa1.5Mg17Nio.5preparedbyMAarebetterthanthatbyHCS.La1.5Mg17Nio.5preparedbyMAcanabsorb6.73mass%hydrogenat523Kwithin1min,and4.92mass%hydrogenat423K.TheimprovementofhydridingpropertiesofLa1.5Mg17Ni0.5alloypreparedbyMAcanbeascribedtotheformationofnano-crystallineanddefectsduringthemechanicalalloying.

  • 标签: HYDRIDING COMBUSTION synthesis mechanical ALLOYING hydrogen
  • 简介:LongafterglowphotoluminescentmaterialsSr2MgSi2O7dopedwithEu2+,Dy3+werepreparedbysol-gelmethod.ThesynthesizedsampleswerecharacterizedbyX-raydiffraction.Theexcitationspectrum,emissionspectrumandlongdecaycurveweremeasuredandanalyzed.XRDpatternindicatesthatphosphoriswithSr2MgSi2O7crystalstructure.Thewiderangeofexcitationwavelengthindicatesthatluminescentmaterialcanbeexcitedbylightfromultravioletraytovisiblelight.Themainpeakofemissionspectrumislocatedat466nm.Sampleexcitedbyvisiblelightcanemitbrightbluelight,andtheafterglowtimelastsmorethan8h.

  • 标签: 发光材料 无机非金属材料 稀土
  • 简介:Tobreakthroughthebottle-neckofquantumyieldinupconversion(UC)core-shellsystem,weelucidatedthattheenergytransferefficiencyincore-shellsystemhadanevidentcontributionfromthechargetransferofinterfacewithrelatedtotwofactors:(1)bandoffsetsand(2)bindingenergyareadensity.Thesetwovariablesweredeterminedbymaterialintrinsicpropertiesandcore-shellthicknessratio.Wefurtherunraveledthemechanismofnon-radiativeenergytransferbychargetransferinduceddipoleattheinterface,basedonaquasi-classicalderivationfromF?rstertyperesonantenergytransfer(FRET)model.Withstablebondingacrosstheinterface,thecontributionsonenergytransferinbothradiativeandnon-radiativeenergytransfershouldalsobeaccountedtogetherinAuzel'senergytransfer(ETU)modelincore-shellsystem.Basedonthediscussionaboutinterfacebonding,bandoffsets,andformationenergies,wefiguredoutthesignificanceofinterfacebondinginducedgapstates(IBIGS)thatplayedasignificantroleforinfluencingthechargetransferandradiativetypeenergytransfer.Theinterfacebandoffsetswereakeyfactorindominatingthenon-radiativeenergytransfer,whichwasalsocorrelatedtocore-shellthicknessratio.Wefoundthattheenergyareadensitywithrelatedtocore/shellthicknessratiofollowedthetrendofBoltzmansigmoidalgrowthfunction.Bythephysicaltrend,thisworkcontributedareferencehowthemulti-layeredcore-shellstructurewasformedstartingfromtheverybeginningwithinminimumsize.Aroutewaspavedtowardsasystematicstudyoftheinterfacetounveiltheenergytransfermechanismincore-shellsystems.

  • 标签: 界面结合 核壳结构 发光材料 壳模型 非辐射能量转移 形成能
  • 简介:采用5水平Box-Behnken设计的反应表面方法论(RSM)被用来优化铈(III)的biosorption到动物和植物起源viz的biowaste材料上。对虾甲壳(PC)和玉米风格(CS)。各种各样的过程参数viz。pH(一:3.0–9.0),生物资源剂量(B:0.05–0.35g/L),起始的金属集中(C:50–350mg/L),接触时间(D:2–6h)并且温度(E:20–60°C)为优化被选择。木头转变被盒子艇长阴谋在现在的盒子中建议。低p值<0.0001验证了模型的意义。为PC的218.3mg/g和为CS的180.2mg/g的最大的Ce(III)举起在最佳条件下面被注意。在平衡等温线之中,Freundlich模型被发现是而兰米尔模型证明最好适合在CS上建议铈biosorption的同类的模式,在PC上建议biosorption的一个异构的模式的最好适合的那个。这被扫描电子显微镜学(SEM)进一步证实。运动研究显示出作为位于这个过程下面的现象建议physisorption的伪first顺序模型的更好的适用性。电影散开被博伊德阴谋的非线性建议。热力学的研究证明这个过程吸热、自发。FTIR分析在Ce(III)biosorption期间证实了酰胺,胺,酉同类和主要白酒组的参予的主要参与。EDAX分析在Ce(III)biosorption期间证实了碳组的主要参予。这是Ce(III)biosorption的参数优化上的第一份报告到用可能从水的环境对Ce(III)的恢复有用的5水平Box-Behnken试验性的设计的biowaste材料上。

  • 标签: 物理吸附 铈(Ⅲ) 平衡等温线 参数优化 生物废料 植物来源