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简介：采用XAFS研究不同制备条件下超细Ni-P非晶态合金中Ni原子配位环境周围的局域结构。结果表明在pH小于11的条件下，样品的非晶化程度随pH的减小而增大；当pH为14时，样品中Ni的区域环境结构与金属Ni的相近。不同退火温度样品的XAFS结果表明，在300℃的温度下退火，超细Ni-P非晶态合金基本晶化生成晶态物相。

简介：采用EXAFS详细研究了系列Ni-Co-B非晶态合金催化剂的结构，结果表明：非晶态Ni-Co-B合金中的金属和非金属之间是一种共价化学键，Co的加入增加了Ni-B非晶态合金的无序度，而B含量的变化对Co-B、Ni-B配位有不同的影响，当样品中Ni、Co含量相同时，存在着协同作用。

简介：采用XAPS和XRD研究Ni-Ce-B超细非晶态合金在退火过程中的结构变化。实验结果表明，在573K的返火温度下，样品仍然保持非晶态结构，仅有少量晶态Ni3B生成；在673K退火温度下、Ni-Ce-B样品晶化生成晶态Ni3B和纳米晶Ni；在773K和更高的温度退火处理后，还有一部分Ni3B并未分解，少量的Ce掺杂使得样品晶化生成的Ni晶格有较大畸变。说明0．3％的Ce对提高Ni-Ce-B样品的稳定性有显著作用。

简介：本文采用XAFS、XRD、DTA三种方法研究化学还原法制备的NiB超细非晶态合金在退火过程中的结构变化及结构与催化性能的关系。XRD和XAFS结果表明，NiB超细非晶态合金的退火晶化过程分两步进行，在325℃的退火温度下，NiB超细非晶态合金晶化生成纳米晶Ni和NiB亚稳物相；在380℃或更高的退火温度下，绝大部分Ni3B进一步晶化分解生成金属Ni物相，其产物中Ni的局域环境结构与金属Ni箔的基本一致。我们发现纳米晶Ni比超细Ni-B非晶态合金或晶态金属Ni粉末有更好的苯加氢催化活性。

简介：TheballmillingofFe-24MnandFe-24Mn-6Simixedpowdershasbeenperformedbythehighenergyballmillingtechnique.ByemployingX-raydiffractionandMoessbauermeasurements.Theccmpositionevolutionduringthemillingprocesshasbeeninvestigated.TheresultsindicatetheformationofparamagneticFe-MnorFe-Mn-Sialloyswithametastablefccphaseasfinalproducts.whichimplythattheFeandMnproceedaco-diffusionmeenanismthroughthesurfaceoffragmentedpowders.Thethermalstabilityandcompositionevolutionoftheas-milledalloyswerediscussedcomparingwiththebulkalloy,.

简介：TheNi-AlalloycontainingCr,FeadditiveswerepreparedasRaneyNiCatalystbyhighenergymilling.ThesizeandsurfacestateofNi-Alalloypowderwerestudiedbyparticlesizeanalyzerandsanningelectronmicroscopy.theStructurewasanalyzedbyXRDandMoessbauermethods.Theresultsshowedthatafterahigh-energymilling(HEM).theNi-Alalloytransformstoanano-scaleNiAlstructurewithrichAl.Byannealingthealloy,ametastableNi2Al3phasecanbeobtained.

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简介：TherearetwotpyesofphasetransformationsinFe-MnandFe-Mn-Sialloyswhenthetemperatureisdecreased,γ(fcc)→ε(hcp)martensitictransformation(MT)andparamagnetic-antiferromagnetictransition(AMT)ofγphase.Fromthethermodynamicpointofview,theformerusuallyappearsinaslightlyhighertemperaturerangethanthelatterbecauseifisgenerallyacceptedthatthemagnetictansitionhasasuppressingeffectonthethermallyinducedεmartensite(Satoetal.,1984.,BogachevandZvigintzeva,1976;Murakamietal.,1987:Yangetal.,1992)GartsteinandRobinkin(1979)eventhoughtthattheγ-εtransformationshouldbeterminatedbelowNeeltemperature(TN)duetothedecreaseoffreeenergyarisingfromtheAMTofγphase.However,someexperimentalresultshaeindicatedtheformationofεphasebelowT(LiandWayman,1994:Fujimori.1966).Inthepresentwert.thebehavorofγ-εtransformationbelowTNwasfurtherinvestigatedbyclectricalresistancemeasurements.

简介：Accordingtothemultipleresearchesinthelastcoupleofyears,laser-inducedbreakdownspectroscopy(LIBS)hasshownagreatpotentialforrapidanalysisinsteelindustry.Nevertheless,theaccuracyandprecisionmaybelimitedbycomplexmatrixeffectandself-absorptioneffectofLIBSseriously.Anovelmultivariatecalibrationmethodbasedongeneticalgorithm-kernelextremelearningmachine(GA-KELM)isproposedforquantitativeanalysisofmultipleelements(Si,Mn,Cr,Ni,V,Ti,Cu,Mo)inforty-sevencertifiedsteelandironsamples.First,thestandardizedpeakintensitiesofselectedspectralinesareusedastheinputofmodel.Then,thegeneticalgorithmisadoptedtooptimizethemodelparametersduetoitsobviouscapabilityinfindingtheglobaloptimumsolution.Basedonthesetwostepsabove,thekernelmethodisintroducedtocreatekernelmatrixwhichisusedtoreplacethehiddenlayer’soutputmatrix.Finally,theleastsquareisappliedtocalculatethemodel’soutputweight.InordertoverifythepredictivecapabilityoftheGA-KELMmodel,theR-squarefactor(R2),Root-mean-squareErrorsofCalibration(RMSEC),Root-mean-squareErrorsofPrediction(RMSEP)ofGA-KELMmodelarecomparedwiththetraditionalPLSalgorithm,respectively.TheresultsconfirmthatGA-KELMcanreducetheinterferencefrommatrixeffectandself-absorptioneffectandissuitableformulti-elementscalibrationofLIBS.

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简介：Themicroscopiceffectivechargesinmirrornuclei51Mnand51Feareinvestigatedwiththeparticle-vibrationcouplingmodelbasedontheself-consistentSkyrme-Hartree-Fockandcontinuumrandom-phase-approximationapproaches.Theisovectorpartsarepredictedtobearound0.15,andtheprotoneffectivechargesarearound1.25e,whichislessthantheempiricalvalueofeeffp=1.5e.Themicroscopiceffectivechargesinneutronrich51Mnareabout10%lessthanitsprotonrichmirror.TheseeffectivechargesarecombinedwiththeshellmodeltocalculatethereducedelectricquadrupoletransitionprobabilityB(E2)valuesin51Mnand51Fe.ItturnsoutthatthemicroscopiceffectivechargeshavewellreproducedtheB(E2)valuesanditsratiointheterminatingstates.

简介：采用水热合成法制备了Ni/CeO2-ZrO2-A12O3催化剂。进行了添加和不添加水蒸气的CH4-CO2催化重整反应，测量了积碳量，并用EXAFS手段测试了催化剂Ni的K吸收边。结果表明，反应前后最近邻Ni—Ni配位距离无明显变化，而配位数却变化明显。无水蒸气反应后Ni-Ni配位数有较大幅度的减少，而添加了水蒸汽，Ni—Ni配位数比反应前减少幅度小。水蒸气的添加能减少积碳量，稳定催化剂中Ni的结构，从而提高催化反应的稳定性。

简介：CO2adsorptiononthesurfaceofhydrotalcite-derivedmixedoxidecatalystswasinvestigatedunderlowpressureglowdischargeplasmainopercindoconditionsviaFT-IRspectroscopy.Nickelcatalystswerepromotedwithvarioustransitionmetalspecies(Ce,Fe,La,Zr)toinfluencetheirphysico-chemicalproperties.FeandZrspeciesweresuccessfullyincorporatedintohydrotalcitebrucitelayers.AftercalcinationformedasinglephasewithNi(Mg,A1)Omixedoxide,whileLaandCespeciesformedseparatephases.ThishadaconsequenceinthedistributionofsurfacebasicsitesaswellasintheaffinitytoCOproduceduponCO2dissociationinplasma.Plasmatreatmentactivatedthesurfaceofpreparedmaterialsandchangedtheirpropertiesviathegenerationofstrongbasicsitesassociatedwithlowcoordinatedsurfaceoxygenanions.Moreover,theCO2adsorptioncapacityofpreparedmaterialsincreasedafterplasmatreatment.

简介：利用金刚石压砧高压装置（DAC），对Ca3Mn2O7的粉末样品进行了高压能散X射线衍射实验。结果表明，由于岩盐层易被压缩，在压力作用下层状钙钛矿结构锰氧化物Ca3Mn2O7的结构不稳定。在0－35GPa压力范围内，Ca3Mo2O7晶体结构发生了两次相变。在1．3GPa左右，由原来的四方相变为正交相，在9．5GPa左右，又由正交相向新的四方相转变。

简介：WestudiedthespatialevolutionoftheFe-Niplasmageneratedbythefundamental(1064nm)andsecond(532nm)harmonicsofaQ-switchedNd:YAGlaser.Theexperimentallyobservedlineprofilesoftheneutraliron(FeI)havebeenusedtoextracttheplasmatemperature(Te)usingtheBoltzmannplotmethod,whereastheelectronnumberdensity(Ne)hasbeendeter-minedfromtheStarkbroadening.Inaddition,westudiedthespatialbehaviorofTeandNewiththevariationoflaserenergyforironplasmabyplacingthetargetmaterial(iron-nickelalloy)inairatatmosphericpressureforbothmodesoftheNd:YAGlaser.

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简介：本文利用XAFS方法研究机械合金化方法制备的Fe100-xCux(x=0,10,20,40,60,70,80,100,x为原子百分比）合金中Fe、Cu原子的局域环境结构随组成的变化。对于Fe100-xCux二元混合物，当x≥40时，Fe原子的近邻配位结构从bcc转变为fcc，但Cu原子的近邻结构保持其fcc不变；与之相反，当x≤20时，Fe原子的近邻配位保持bcc结构而Cu原子的近邻配位结构从fcc转变为bcc结构。XAFS结果还表明fcc结构的Fe100-xCux中Fe的无序因子σ（0．009A）比bcc结构的Fe100-xCux中的σ（0．081A）大得多；并且在同一机械合金化Fe100-xCux（x≥40）样品中Fe原子的σ（0．099A）比Cu原子的σ（0．089A）大。这表明机械合金化的Fe100-xCux样品中Fe和Cu原子可以有相同的局域结构环境但不是均匀的过饱和固溶体，而是fcc或bcc合金相同时存在Fe富集区和Cu富集区。

简介：不同退火温度处理后的纳米非晶态NiB和NiP合金催化剂XAFS和XRD的结果表明，在300℃温度退火后，纳米非晶态NiB合金晶化生成纳米晶Ni和晶态Ni3B中间态；纳米非晶态NiP合金直接晶化生成稳定的晶态Ni和Ni3P。在500℃温度退火后，NiB和NiP样品都晶化为金属Ni，但NiB样品中的Ni原子周围的局域结构与金属Ni箔的几乎相同，而NiP样品由于Ni原于受到元素P的影响，生成的晶态Ni的结构有较大的畸变，结构与金属Ni相差很大。