学科分类
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202 个结果
  • 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.

  • 标签: 铁原子 Fe2铁簇 NO 密度泛函 两态反应
  • 简介:Toeffectivelysolvetheagglomerationproblemsinthesolidstatereactionprocess,pre-addingglucoseisadoptedtothesynthesisofLiFePO4/CenergymaterialsusingFe–Pwasteslag.Theaverageparticle&grainsizeofLiFePO4/Cdecreases,andtheimpuritiesinLiFePO4/Ccompositesreducetoagreatextent.Itmakesgreatsensetothemassindustrialproduction.Theoptimumsynthesisconditionsdeterminedinthisworkarebasedontheorthogonalexperiments.Thesamplessynthesizedinascaleof500gexhibithighpurity,excellentelectrochemicalperformance,highreactionactivity,goodreversibility,andlowpolarizationlevel.Thedischargecapacitiesare145,134,117,and102mAh/gatthecurrentdensitiesof0.1C,0.2C,0.5Cand1C,respectively.ThisworkputsforwardapracticalsuggestionformassproducingenvironmentalbenignandlowcostLiFePO4/Cascathodematerialsoflithiumionbatteries.

  • 标签: 材料使用 工业生产 磷渣 能源 最佳合成条件 锂离子电池
  • 简介:AnFEanalysisprocedurewaspresentedtopredictthebehaviorofsoilogeogridinterctionunderautomobileloading.Thedynamicinteractionsbetweenthetransversebars,thelongitudinalribsandthesoilweresimulatedbyasystemconsistingofnonlinearsprings,dashpotsandmasses,tostudythedeformationpropertiesofthereinforcedsoil.Theequivalentstiffnessanddampingratioscouldbedeterminedwiththeshakingtable.Thedynamicresponsesofareinforcedsubgradewereanalyzedwiththe3Dfiniteelementapproach.Thisapproachisprogrammedandappliedtoanalyzethesoilogeogridinteractionunderdynamicloading.Thecomparativeanalysisoftheresponseofthereinforcedsubgradeandthatofthesubgradewithoutreinforcementshowsthatthegeogridplacedatthebottomofthebaselayermayeffectivelyreducetheaccumulativeplasticdeformationduetothecyclicautomobileloading.

  • 标签: 道路力学 车辆负载 路基加固 变形 弹性减阻装置系统
  • 简介:张力爬精细的Fe-Mn二进制合金containing0.42-1.21wt.%Mn的行为从房间温度在温度范围被调查了到475Kunder10-50MPa。张力的测试以紧张率在uniaxail负担下面以经常的小标题速度被执行10(-4)s(-1)。压力代表和激活精力决心澄清变丑机制。稳定的状态的获得的变化爬关于为Fe-Mn二进制合金的应用压力的率在大约20MPa展出二不同政体,显示一个可能的变化在爬机制。平均压力代表是约2.2,它是在合金滑动的谷物boundry的一个特征。为塑料流动的激活精力从135~92kJ/mol变化,取决于Mn内容。

  • 标签: 蠕变 Fe-Mn二元合金 温度范围 张力测试
  • 简介:ThedetailedmicrostructuresofNi80Fe20/Fe50Mn50superlatticeshavebeencharacterizedusingbothx-raydiffractiontechniquesandtransmissionelectronmicroscopy.Theobrivouslayeredstructure,typicalcolumnstructureandtwinswhichexistinNi80Fe20/Fe50Mn50superlatticeswereobservedthroughperformingtransmissionmicroscopy.Bycombiningthetechniqueoflowanglex-rayreflectivity(specularandoff-specularscans)withtheanomalousscatteringeffectandhigh-anglex-raydiffraction(usingconventionalx-ray),wequantitativelyanalysedthemicrostructuralvariationasafunctionofannealingtemperature.Itisfoundthatthelateralcorrelationlength,the(111)peakintensityofthesuperlatticesandtheaveragemultilayercoherencelengthallincreasewithariseinannealingtemperatureannealingcandecreasetherootmean-squareroughnessattheinterfacesofNi80Fe20/Fe50Mn50superlattices.theobtainedmicrostructuralknowledgewillbehelpfulinunderstandingthemagneticpropertiesoftheni80Fe20/Fe50Mn50exchangebiassystem.

  • 标签: Ni80Fe20/Fe50Mn50超晶格 X射线衍射分析 微观结构 电子输运
  • 简介:ThecatalyticactivityofFe/ZSM-5fortheselectivereductionofNOtoN2withmethaneinthepresenceofexcessO2wasstudied.Fe/ZSM-5catalystswithvariousFeloadingswerepreparedbyimpregnationmethod.ItiswellknownthatmethaneisinactivewhenFe/ZSM-5asthecatalystfortheselectivecatalyticreduction(SCR)ofNOwithmethane.However,thispapershowsthatwhenthecontentofFewasabout0.5%,Fe/ZSM-5showedhighercatalyticactivityandselectivityofmethane,andputforwardmeasurableactivationforCH4isanimportantfactorforthereactionofremovalofNOxwithCH4.

  • 标签: CATALYTIC activity Fe/ZSM-5 SELECTIVE CATALYTIC REDUCTION
  • 简介:Threetypesofcarbonnano-onions(CNOs)includingNi@CNOs.Fe3C@CNOsandFe0.64Ni0.36@CNOsnanoparticleshavebeensynthesizedbycatalyticdecompositionofmethaneat850℃usingnickel,ironandiron-nickelalloycatalysts.Comparativeandsystematicstudieshavebeencarriedoutonthemorphology,structuralcharacteristicsandgraphiticcrystallinityoftheseCNOsproducts.Furthermore,theelectrochemicalhydrogenstoragepropertiesofthreetypesofCNOshavebeeninvestigated.MeasurementsshowthattheNi@CNOshavethehighestdischargecapacityof387.2mAh/g,coiTespondingtoahydrogenstorageof1.42%.ThiscomparisonstudyshowstheadvantagesofeachcatalystinthegrowthofCNOs.enablingthecontrollablesynthesisandtuningthepropertiesofCNOsbymediatingdifferentmetalsandtheiralloyforusinginthefuelcellsystem.

  • 标签: 合金催化剂 合成效果 纳米颗粒 储氢性能 碳化铁 电化学
  • 简介:当用于含能材料的表面涂层时,ParyleneC涂层优良的电绝缘性能,使得涂层后的炸药表面容易产生静电积累,因此可能会降低炸药的静电安全性。通过试验初步考核了ParyleneC涂层后炸药的静电摩擦感度,并与未涂层炸药以及带聚氨酯复合涂层的炸药进行对比。实验简易装置如图1所示。

  • 标签: PARYLENE 表面涂层 静电性能 炸药 电绝缘性能 含能材料
  • 简介:研究了在盐酸介质中,三价铁离子能将盐酸氯丙嗪氧化成一种红色的物质,且氧化的程度与盐酸氯丙嗪的量呈正比关系,据此建立了测定盐酸氯丙嗪的分光光度分析方法。实验中最大吸收波长为530nm,摩尔吸光系数为5.13×103L/(mol·cm),盐酸氯丙嗪的量在5-250μg/10mL范围内与吸光度A有良好的线性关系,方法用于盐酸氯丙嗪药物的测定,其相对标准偏差为0.11%-0.19%,加标回收率为95.0%-97.0%。

  • 标签: 分光光度法 三价铁离子 盐酸氯丙嗪
  • 简介:Wehavestudiedtheelectronic,bondingandenergeticcharacteristicsoftheFe-Sibinarysystemusingthetight-bondingextendedHuckelmethod.AmongtheFe-Sibinarycompounds,FeSihasthemostsymmetricgeometricarrangementinthecrystalstructure.Italsopossessesthelargestcohesiveenergyperatom.ThiscorrelatestothefactthatFeSiisthemoststablecongruently-meltingcompoundinthebulkphasediagram.Anestimateofinteractionenergiesbetweendifferentatomsisalsogiven.

  • 标签: FE-SI BINARY system BONDING EXTENDED Huckel
  • 简介:为研制具有较宽频带微波吸收性能的材料,采用机械合金化法制备CoxFe80-xSi20(x=0,6,10,14摩尔百分数)合金粉体,使用SEM、XRD和矢量网络分析仪等测试手段,研究了合金粉体微观结构及Co-Fe-Si合金微波吸收性能。结果表明:制备的合金粉末呈片状,主要由-Fe相组成;Co的添加使Co-Fe-Si合金出现两个微波吸收峰。在较高频段处的微波吸收峰值随Co的添加先增大后减小。在涂层厚度为1.8mm时,x=10的合金低频处的反射率最小值最小,合金吸波峰频率和峰值分别为6.2GHz和-14.8dB,合金在高频处吸波峰频率和峰值分别为18GHz和-8.8GHz,合金反射率低于-5dB的带宽达14GHz,具有良好的微波吸收宽频效应。

  • 标签: Co-Fe-Si合金 吸波材料 电磁参数 反射率
  • 简介:HighactiveandstablegoldcatalystssupportedoncrystallineFe2O3andCeO2/Fe2O3werepreparedviathedeposition-precipitationmethod.ThecatalystwithaAuloadof1.0%calcinedat180°CshowedaCOconversionof100%at-8.9°C,whileAu/CeO2/Fe2O3convertedCOcompletelyat-16.1°C.Evenhavingbeencalcinedat500°C,Au/Fe2O3stillexhibitedsignificantcatalyticactivity,achievingfullconversionofCOat61.6°C.ThecatalystwithalowAuloadof0.5%couldconvertCOcompletelyatroomtemperatureandkepttheactivityunchangedforatleast150h.N2adsorption-desorptionmeasurementsshowthatthecrystallinesupportspossessedahighspecificsurfaceareaofabout200m2/g.CharacterizationsofX-raydiffractionandtransmissionelectronmicroscopyindicatethatgoldspecieswerehighlydispersedasnanoorsub-nanoparticlesonthesupports.Evenafterthecatalystwascalcinedat500°C,theAuparticlesremainedinanano-sizeofabout6―10nm.X-rayphotoelectronspectrarevealthatthesupportedAuexistedinmetallicstateAu0.ThemodificationofAu/Fe2O3byCeO2provedtobebeneficialtotheinhibitionofcrystallizationofFe2O3andthestabilizationofgoldparticlesindispersedstate,consequentlypromotingcatalyticactivity.

  • 标签: 金催化剂 CO氧化 氧化铁 Au/Fe2O3 去甲肾上腺素 X射线光电子能谱
  • 简介:ThepartialoxidationofethanoltohydrogenwasinvestigatedoverNi/Fe/Lacatalystspreparedbytheco-precipitationmethod.TheeffectsofintroductionofLapromoterandthereactiontemperatureonthecatalyticperformancewerestudied.ItwasfoundthattheintroductionofLaintoNi/Fecatalystsishelpfultoincreasetheselectivitytohydrogenandthestabilityofthecatalysts.TheresultsofXRDandXPScharacterizationshowthatthestructureofthecatalystwaschangedduringthereaction.TheexistenceofLaFeO3speciesispossiblythemainreasonoftheincreaseofthecatalyststability.

  • 标签: 乙醇 局部氧化 镍/铁催化剂 氢转移
  • 简介:Thediffusionmechanismofboroninbcc-Fehasbeenstudiedbyfirst-principlescalculations.Thediffusioncoefficientsoftheinterstitialmechanism,theB–monovacancycomplexmechanism,andtheB–divacancycomplexmechanismhavebeencalculated.ThecalculateddiffusioncoefficientoftheinterstitialmechanismisD0=1.05×10-7exp(-0.75eV/kT)m2·s-1,whilethediffusioncoefficientsoftheB–monovacancyandtheB–divacancycomplexmechanismsareD1=1.22×10-6f1exp(-2.27eV/kT)m2·s-1andD2≈8.36×10-6exp(-4.81eV/kT)m2·s-1,respectively.Theresultsindicatethatthedominantdiffusionmechanisminbcc-Feistheinterstitialmechanismthroughanoctahedralinterstitialsiteinsteadofthecomplexmechanism.ThecalculateddiffusioncoefficientisinaccordancewiththereportedexperimentresultsmeasuredinFe–3%Si–Balloy(bccstructure).Sincethenon-equilibriumsegregationofboronisbasedonthediffusionofthecomplexesassuggestedbythetheory,ourcalculationreasonablyexplainswhythenon-equilibriumsegregationofboronisnotobservedinbcc-Feinexperiments.

  • 标签: 第一原理计算 硼扩散 BCC Fe 质扩散系数 非平衡偏聚
  • 简介:Uniformlysizedα-Fe2O3hexagonalplateletsweresynthesizedbyahydrothermalprocessusingFe(OH)3suspensionandlargeamountofNaOH.ThereactionproductswerecharacterizedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM),transmissionelectronmicroscopy(TEM),selectedareaelectrondiffraction(SAED),andavibratingsamplemagnetometer(VSM).Theresultsshowthatthehexagonalplateletsarefine,monodisperseandconsistingofsingle-crystals.Themagnetichysteresis(M-H)curveofthesamplesmeasuredatroomtemperatureindicatesthattheα-Fe2O3micro-plateletsexhibitferromagneticbehaviorswithrelativelylowcoercivity.

  • 标签: Fe2O3 六角片状 单分散 水热法合成 振动样品磁强计 扫描电子显微镜
  • 简介:Fe∶ZnSe晶体的吸收光谱进行了实验测量和理论计算。通过测量Fe∶ZnSe晶体的透射光谱,给出了Fe∶ZnSe晶体的整体损耗曲线;受限于分光光度计的反射光谱测量范围,无法对该晶体在3μm附近的反射光谱进行直接测量。因此,基于几何光学理论,对晶体的反射光谱进行了理论计算。经对比,计算得到的反射光谱曲线与分光光度计可测区间的反射光谱吻合较好。这样,通过理论计算与实验测量相结合的方法,得到了可信的晶体反射光谱数据。在考虑晶体反射损耗的情况下,计算得到了晶体的吸收光谱曲线,并在此基础上计算了晶体的掺杂浓度,结果与标称掺杂浓度相符。

  • 标签: 中红外光源 吸收谱 掺杂浓度