简介:三新奇Ba_5RNiNb_9O_(30)(R=La,Nd和Sm)陶艺在BaO-R_2O_3-NiO-Nb_2O_5系统被准备并且描绘。所有三混合物areparaelectjicphasesadopting。在房间温度的充满的四角形的钨铜(TB)结构。在1MHz,Ba_5RNiNb_9O_(30)陶艺有高电介质在范围193-245.3,在范围0.0059-0.0087的低绝缘的损失,和在范围的绝缘的常数(tau_e)的温度系数的常数-1140-1310X10~(-6)中心点degC。他们绝缘的常数的温度系数显著地Ba_5RNiNb_9O_(30)与那些相比被减少(R=La,Nd,Sm)陶艺。
简介:采用Sol—gel法合成了BaTiO3、BaTi2O5和BaTi2O9粉末,利用XRD和SEM研究了它们的晶相和微观结构。在较低温度烧结得到的粉末都存在一定量的杂相,随着烧结温度的升高,杂相逐渐消失。在1000℃以上温度烧结,可以得到单相BaTiO3和BaTi2慨粉末,而单相BaTi09粉末则在1300℃以上温度烧结得到。随着n(Ba)/n(Ti)减小,所得单相的烧结温度逐渐升高。随着烧结温度的升高,BaTiO3、BaTi2O5和BaTi4O9粉末的晶粒逐渐长大。800℃以上温度烧结得到的四方BaT[03钙钛矿相粉末主要由方形和圆形的晶粒组成;1100℃烧结得到的单斜BaTiO5相粉末主要由近似菱形的晶粒组成;在1200℃烧结得到的正交BaTi4O9相粉末基本由长形的晶粒组成。
简介:AdditionofAl-5Ti-1Balloytomoltenaluminumalloyscanrefineα-Algrainseffectivelyandtherebyimprovetheirstrengthandtoughness.TiAl3andTiB2inAl-5Ti-1Balloyarethemainsecondary-phaseparticlesforrefinement,whiletheunderstandingontheeffectoftheirsizesonα-Algrainrefinementcontinuestobefragmented.Therefore,Al-5Ti-1Balloyswithvarioussizesandmorphologiesofthesecondary-phaseparticleswerepreparedbyequalchannelangularpressing(ECAP).Evolutionofthesecondary-phaseparticlesduringECAPprocessandtheirimpactonα-AlgrainrefinementwerestudiedbyX-raydiffractionandscanningelectronmicroscope(SEM).ResultsshowthatduringtheECAPprocess,micro-cracksfirstlyappearedinsideTiAl3particlesandthengraduallyexpanded,whichresultedincontinuousrefinementofTiAl3particles.Inaddition,micro-distributionuniformityofTiB2particleswasimprovedduetotheimpingementofTiAl3particlestoTiB2clustersduringdeformation.ExcessivelylargesizesofTiAl3particleswouldreducethenumberofeffectiveheterogeneousnucleusandthusresultedinpoorgrainrefinementeffectiveness.Moreover,excessivelysmallTiAl3particleswouldreduceinhibitoryfactorsforgraingrowthQandweakengrainrefinementeffectiveness.Therefore,anoptimalsizerangeof18-22μmforTiAl3particleswassuggested.
简介:Inducedembryonicstemresourcesfortheobservationofthecell(ES)cellsareexpectedtobepromisingcellbehaviorsindevelopmentalbiologyaswellastheimplantationincelltreatmentsinhumandiseases.ArecombinantE-cadherinsubstratumwasdevelopedasacellrecognizablesubstratumtomaintaintheEScells'self-renewalandpluripotencyatsinglecelllevel.Furthermore,thegenerationofvariouscelllineagesindifferentgermlayers,includinghepaticorneuralcells,wasachievedonthechimericproteinlayerpreciselyandeffectively.Theinductionandisolationofspecificcellpopulationwascarriedoutwiththeenhancingeffectofotherartificialextracellularmatrices(ECMs)inenzyme-freeprocess.ThemurineEScell-derivedcellsshowedhighlymorphologicalsimilaritiesandfunctionalexpressionstomaturedhepatocytesorneuralprogenitorcells.
简介:Na5+xYAlxSi4-xO12superionicconductorsarerhombohedralR3cspacegroup.Theirstructuresarecharacterizedby(Alx/4Si1-x/4)O4tetrahedralinkedtoformpuckered(Al3xSi4-x)4O35ringsparalleltothebasalplaneofthehexagonalcell.Theserings,separatedbypartsofsodiumoxygenpolyhedron,arestackedtoformlargerigidcolumsparalleltocaxis.Thecolumnsarelinkedby[YO6]octahedratoformathree-dimensionalFrameworkwithlargechannelsbetweentherings.PartsofNaionslocatedinthecoresofthecolumnsaremovable.Intermsoftheconductionmechanism,theconcentrationofconductingNa+ionswascarriedoutandcomparedwiththeexperimentalresults.Itwasfoundthatthetheoreticalvaluesaccordwiththeexperimentalresults.
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简介:Inthisstudy,Almatrixcompositesreinforcedby7.5and15vol.%B4CparticlesandalsomonolithicAl(AlwithouttheB4Cparticles)wereproducedbywetattritionmillingandsubsequenthotforwardextrusionprocesses.Themicrostructureofthecomposites,evaluatedbyscanningelectronmicroscopy(SEM),showedthattheB4CparticleswereproperlydistributedintheAlmatrix.MechanicalpropertiesoftheAI/B4CcompositesandmonolithicAlwereinvestigatedbytensile,wearandhardnesstests.TheresultsrevealedthatwithincreasingcontentofB4Cparticles,thetensilestrengthandmicrohardnessofcompositesincreasedbuttheelongationdecreased.Inaddition,thetensilestrengthandmicrohardnessofcompositesampleswerehigherthanthoseofmonolithicAl.ThedensitymeasurementsrevealedthatthedensityofcompositesdecreasedwithincreasingcontentoftheB4Cparticles.
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简介:Anovelfluorescentprobe9-(4-(1,2-diamine)benzene-N1-phenyl)acridine(DABPA)wassynthesizedforthedetectionofnitricoxide(NO)andcharacterizedbyIR,1H-NMRandEI-MSspectroscopy.Basedonaphotoelectrontransfermechanism,thefluorescenceintensitiesofDABPAwereinvestigatedwiththedifferentconcentrationsofNO.Undertheoptimalexperimentalconditions,thefluorescenceintensityofDABPAhadagoodlinearrelationship(R2=0.9977)withNOconcentrationintherangefrom1×10-7to1.5×10-6mol/Lwithadetectionlimitof1×10-8mol/L.ThecytotoxicityinducedbyDABPAwasevaluatedbytheMTT(3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazoliumbromide)assayforbiologicalapplication.Furthermore,theprobeDABPAhadalsobeensuccessfullyappliedtoreal-timeimageNOproducedinPC12cellsinthepresenceofL-arginine.
简介:采用柠檬酸络合和浸渍两步法制备了一系列B-xMo共掺杂BiVO4可见光光催化剂,并采用XRD、XPS、SEM、EDS、BET和UV-vis等表征和分析。以降解甲基橙(MO)、亚甲基蓝(MB)、金橙Ⅱ号(AOⅡ)和罗丹明B(RhB)溶液为指针反应,考察掺杂对BiVO4可见光催化活性的影响。结果表明:B-Mo共掺杂能抑制BiVO4晶粒生长,比表面积增大,共掺杂后BiVO4禁带宽度窄化,且氧空位较单掺杂增加。当Mo掺杂量为2.5%(原子分数)时制备的B-2.5Mo-BiVO4对甲基橙的降解率达96%左右,且该样品也能有效降解亚甲基蓝(MB)、金橙Ⅱ号(AOⅡ)和罗丹明B(RhB)溶液。
简介:Withpositronannihilationradiationonedimensionangular-correlationdevice,itismeasuredthatpositronannihilationradiationonedimensionangular-correlationcurvesofpolycrystalsodiumionconductorNa5Y1-xCrxSi4O12(NYCS)system.Afterelectronmomentumdistributioncurvesarenormalized,linearparametersarecalculated.TheparametersH,WandSshowthechangeofNa+ionvacancyconcentrationinNYCSseriessamples.TheresultsshowthatparametersH,WandSofonedimensionangular-correlationcurvesofthosesamplesvarygreatlywithCr2O3contents.WithCr2O3contentincreasing,HandSparametersincrease,butWdecreases,andreachesextremesatx=0.05;thenwithCr203addingcontinually,parametersHandSdecreasegradually,parameterWincreasesgradually.Thisshowsthat,inaddtiontoCr2O3,theconductivityhascloserelation
简介:采用单辊法制备了宽20mm、厚25μm的Fe78Si9B13合金带材,用绕带机将其绕制成环型磁芯,然后将磁芯进行退火处理,结果表明,随着退火温度的升高,Fe78Si9B13非晶磁芯的初始磁导率m、饱磁感应强度Bs和矫顽力Hc呈先增大后减小的趋势,当退火温度达到450℃时,磁化曲线呈现出一定的线性关系,即恒导磁特性。将经4500(=/100min退火的Fe78Si9B13非晶磁芯用环氧树脂进行封装后,环氧封装后μi和Bs减小,而Hc和损耗Ps增大,磁化曲线和损耗曲线的形状与封装前相同。
简介:Anovel,Ti-6A1-4V(Ti64)/Hydroxyapatite(HAat5%byweightconcentration)metal/ceramiccompositehasbeenfabricatedusingelectronbeampowderbedfusion(EPBF)additivemanufacturing(AM):specifically,thecommercialelectronbeammelting(EBMR)process.InadditiontosolidTi64andTi64/5%HAsamples,fourdifferentunitcell(model)open-cellularmeshstructuresfortheTi64/5%HAcompositewerefabricatedhavingdensitiesrangingfrom0.68to1.12g/cm^3,andcorrespondingYoung'smodulirangingfrom2.9to8.0GPa,andcompressivestrengthsrangingfrom-3to11MPa.ThesolidTi64/5%HAcompositeexhibitedanoptimaltensilestrengthof123MPa,andelongationof5.5%incontrasttoamaximumcompressivestrengthof875MPa.Boththesolidcompositeandmeshsamplesdeformedprimarilybybrittledeformation,withthemeshsamplesexhibitingerratic,brittlecrushing.Solid,EPBF-fabricatedTi64sampleshadaVickersmicroindentationhardnessof4.1GPawhiletheTi64/5%HAsolidcompositeexhibitedaVickersmicroindentationhardnessof6.8GPa.ThelowestdensityTi64/5%HAcompositemeshstrutsectionshadaVickersmicroindentationhardnessof7.1GPa.Opticalmetallography(OM)andseanningelectronmicroscopy(SEM)analysisshowedtheHAdispersoidstobehighlysegregatedalongdomainorgrainboundaries,buthomogeneouslydistributedalongalpha(hcp)plateletboundarieswithinthesedomainsintheTi64matrixforboththesolidandmeshcomposites.Thealphaplateletwidthvariedfrom-5μmintheEPBF-fabricatedTi64to-1.1μmfortheTi64/5%HAmeshstrut.TheprecursorHApowderdiameteraveraged5μm,incontrasttothedispersedHAparticlediametersintheTi64/5%HAcompositewhichaveraged0.5μm.ThisworkhighlightstheuseofEPBFAMasanovelprocessforfabricationofatruecompositestructure,consistingofaTi64matrixandinterspersedandexposedHAdomains,whichtotheauthorsknowledgehasnotbeenreportedbefore.Theresultsalsoillustratetheprospectsnotonlyforfabrica