简介:Inthiswork,compressive,flexuralandsplittensilestrengthtogetherwithcoefficientofwaterabsorptionofhighperformanceself-compactingconcretecontainingdifferentamountofFe2O3nanoparticleshavebeeninvestigated.ThestrengthandthewaterpermeabilityofthespecimenshavebeenimprovedbyaddingFe2O3nanoparticlesinthecementpasteupto4.0wt%.Fe2O3nanoparticleasaforeignnucleationsitecouldaccelerateC-S-HgelformationasaresultofincreasedcrystallineCa(OH)2amountespeciallyattheearlyageofhydrationandhenceincreasethestrengthofthespecimens.Inaddition,Fe2O3nanoparticlesareabletoactasnanofillersandrecovertheporestructureofthespecimensbydecreasingharmfulporestoimprovethewaterpermeability.Severalempiricalrelationshavebeenpresentedtopredicttheflexuralandthesplittensilestrengthofthespecimensbymeansofthecorrespondingcompressivestrengthatacertainageofcuring.Acceleratedpeakappearanceinconductioncalorimetrytests,moreweightlossinthermogravimetricanalysisandmorerapidappearanceofpeaksrelatedtohydratedproductsinX-raydiffractionresultsindicatethatFe2O3nanoparticlesupto4wt%couldimprovethemechanicalandthephysicalpropertiesofthespecimens.
简介:Toimprovetheinitialcoulombicefficiencyandbulkdensityoforderedmesoporouscarbons,activeFe2O3nanoparticleswereintroducedintotubularmesoporechannelsofCMK-5carbon,whichpossesseshighspecificsurfacearea(>1700m2g-1)andlargeporevolume(>1.8cm3g-1).FineFe2O3nanoparticleswithsizesintherangeof57nmwerehighlyandhomogenouslyencapsulatedintoCMK-5matrixthroughammonia-treatmentandsubsequentpyrolysismethod.TheFe2O3loadingwascarefullytailoredanddesignedtowarrantahighFe2O3contentandadequatebufferspaceforimprovingtheelectrochemicalperformance.Inparticular,suchFe2O3andmesoporouscarboncompositewith47wt%loadingexhibitsaconsiderablystablecycleperformance(683mAhg-1after100cycles,99%capacityretentionagainstthatofthesecondcycle)aswellasgoodratecapability.Thefabricationstrategycaneffectivelysolvethedrawbackofsinglematerial,andachieveahigh-performancelithiumelectrodematerial.
简介:TheballmillingofFe-24MnandFe-24Mn-6Simixedpowdershasbeenperformedbythehighenergyballmillingtechnique.ByemployingX-raydiffractionandMoessbauermeasurements.Theccmpositionevolutionduringthemillingprocesshasbeeninvestigated.TheresultsindicatetheformationofparamagneticFe-MnorFe-Mn-Sialloyswithametastablefccphaseasfinalproducts.whichimplythattheFeandMnproceedaco-diffusionmeenanismthroughthesurfaceoffragmentedpowders.Thethermalstabilityandcompositionevolutionoftheas-milledalloyswerediscussedcomparingwiththebulkalloy,.
简介:FenanowirearraywithstrongshapeanisotropywasemployedasthesoftphaseinNd-Fe-Bbasednanocomposites.TheeffectsoftheFenanowiredistributiononmagneticpropertiesofthenanocompositeswereinvestigatedbymicromagneticsimulation.TheresultsindicatethattheshapeanisotropyofFewiresaddedinthesamedirectionastheuniaxialmagnetocrystallineanisotropyofthehardphasecannotincreasethecoercivityofthenanocomposite.Whenthenanowiresaredistributedperpendiculartotheeasyaxisofthehardphase,theshapeanisotropyofsoftphasecanretardthemomentsfromrotatingtothefullreverseddirection,leadingtoenhancedcoercivity.Inaddition,withincreasingthenanowirediameter,thecoercivityofthenanocompositedecreases,butthedipolarinteractionshowsdifferentrolesinmagneticreversalofnanocompositefordifferentdistributionsofnanowires.ThecurrentresultssuggestthatthecoercivityoftheNd2Fe14B/α-Fenanocompositecanbeenhancedbyintroducingthesoftmagneticnanowirearraywiththediameterlessthantheexchangelengthandwiththelongaxisalongthedirectionotherthantheeasyaxisofhardphase.
简介:铁矿石经浓盐酸和少量的SnCl2溶液加热到45℃溶解后,用SnCl2-TiCl3还原滴定Fe(Ⅲ),使Fe(Ⅲ)还原为Fe(Ⅱ),再以K2Cr2O7滴定全铁含量。本方法对实验操作温度,试样溶解酸的选择有一定的要求,宜选用非氧化性强酸在30-60℃溶解矿样。
简介:摘要目的分析恩施地区2005至2014年眼球摘除原因,并比较前5年与后5年原因的变化趋势.方法分析在2005-2009年(136例)与2010-2014年(213例)期间于我院行眼球摘除手术的349例患者的主要原因,比较前5年与后5年眼球摘除原因构成比的差异.结果分析比较眼外伤组、恶性肿瘤组及内眼手术组二者有显著性差异,眼外伤组及内眼手术组有明显降低趋势,恶性肿瘤组增高.结论眼外伤的预防与积极的救治是挽救眼球的有力措施.眼科医疗技术的提高降低了丧失眼球的风险.关键词恩施地区;眼球摘除;原因;回顾性研究
简介:利用密度泛函理论(DensityFunctionalTheory)中的B3LYP方法在6-311+G(d,p)的计算水平上研究了Fe/Fe_2与NO反应的相关微观机理.全参数优化了Fe+NO和Fe_2+NO反应体系在不同重态反应势能面上各驻点的几何结构,并用频率分析法以及内禀反应坐标(IntrinsicReactionCoordinate)方法对过渡态进行了验证,得到了相对应的反应的微观反应路径.用"两态反应"分析反应机理,计算结果表明2个体系的优先选择路径均为低自旋态进入和高自旋态离开反应.通过对2个体系反应活化能的比较,Fe_2+NO体系更易进行.