简介:ThepartialoxidationofethanoltohydrogenwasinvestigatedoverNi/Fe/Lacatalystspreparedbytheco-precipitationmethod.TheeffectsofintroductionofLapromoterandthereactiontemperatureonthecatalyticperformancewerestudied.ItwasfoundthattheintroductionofLaintoNi/Fecatalystsishelpfultoincreasetheselectivitytohydrogenandthestabilityofthecatalysts.TheresultsofXRDandXPScharacterizationshowthatthestructureofthecatalystwaschangedduringthereaction.TheexistenceofLaFeO3speciesispossiblythemainreasonoftheincreaseofthecatalyststability.
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.
简介:对Fe(Ⅲ)单独沉淀、Fe(Ⅱ)单独沉淀、Ce(Ⅳ)单独沉淀、Fe(Ⅲ)-Ce(Ⅳ)和Fe(Ⅱ)-Ce(Ⅳ)沉淀5种制备体系产物去除As(Ⅴ)性能进行了比较,结果显示Fe(Ⅱ)-Ce(Ⅳ)体系最优。进一步优化评价Fe(Ⅱ)-Ce(Ⅳ)制备体系中铈的加入量。基于经济一性能平衡的考虑,优选得到了Fe(Ⅱ)-Ce(Ⅳ)体系中Ce(Ⅳ)加入量为0.03mol/L的吸附剂Fe(Ⅱ)-Ce(Ⅳ)03(简称FC),其饱和吸附容量达到85mg/g。动力学测试表明,FC去除As(Ⅴ)过程符合准二级反应动力学过程。在pH=4~7范围内,吸附容量受pH值影响不明显。对FC材料造粒后的吸附剂颗粒进行再生寿命评价,批量试验结果显示其能够重复利用7次。颗粒柱试验结果表明,在空^U流速(SV)分别为10h^-1、20h^-1、30h^-1时,出水砷穿透前(〉10μg/L)分别刘应4000、2400、2160倍的倍柱体积处理赶。对FC材料进行的表征测试显示,FC呈无定形结构,其质子位密度为9.97个/nm^2,质子化常数pK1=3.09,pK2=-10.02。
简介:磁性的元素Fe,公司和Ni的线性热扩大(CLE)的系数用与MATLAB计算相结合的理论模型从试验性的信息被估计。模型参数能精确地被决定,并且估计的数据在对试验性的结果的好同意。便于评价,热扩大的理论被使用把CLE分开成它的无磁性、磁性的部件。对CLE的无磁性的贡献的计算基于MnBi/NdFeB混血儿的修改Grc性质结合的磁铁都逐渐地减少,当混合磁铁的密度几乎线性地改善时。在293-398的一个温度范围?K,混合磁铁的coercivity温度系数从0.59逐渐地改善?%比较。建模和频率与二低角落频率认为压力消除阀门是一个秒顺序系统是合理的试验性的结果表演。PID控制,死了的乐队赔偿控制和鷸?鷸??
简介:ThesolidsolubilityofCe、La、SmandNdinFeorNiatvarioustemperaturewasdeterminedbymeansofadiffusion-couplemethodwiththeaidofanelectronprobemicroanalyzer.Twomethods,namelyareamethodandwholerangemethod,wereproposedfordataprocessinginthepresentpaper.Theprincipleandre-latedproblemsintheexperimentaldeterminationofthesolidsolubilityofrare-earthelementsinFeorNibyuseoftheabovementionedmethodswerealsodiscussed.
简介:Tofindthedifferenceindynamiccharacteristicsbetweenconventionalmonohullshipandwavepenetratingcatamaran(WPC),aWPCwastakenasanobject;itsdynamiccharacteristicswerecomputedbytransfermatrixmethodandfiniteelementmethodrespectively.Accordingtothecomparisonofthenaturefrequencyresultsandmodeshaperesults,thefactthatFEMmethodismoresuitabletodynamiccharacteristicsanalysisofaWPCwaspointedout,specialfeaturesondynamiccharacteristicsofWPCweregiven,andsomebeneficialsuggestionsareproposedtooptimizethestrengthofaWPCindesignperiod.
简介:Understandingtheeffectsoforganicacids(OA)onthetransformationofFeandMntosurfacewaterfromtheweatheringcoalgangueisofgreatbene?ttoriskassessmentandremediationstrategiesforcontaminatedwaterandsoil.BasedontheinvestigationonsurfacewaterinthecentralcoaldistrictsoftheGuizhouProvince,18watersampleswerecollectedforheavymetalanalysis.TheresultsindicatedthatthepHvalueofsurfacewaterislow(3.11–4.92),andFeconcentration(1.31–5.55mgL-1)andMnconcentration(1.90–5.71mgL-1)were,onaverage,10.86and34.33timesthelimitofSurfaceWaterQualityStandards,respectively.InordertoevaluatetheeffectsoftheOAonthedissolutionofFeandMnfromtheweatheringcoalgangue,columnelutionandbatchleachingexperimentswereconducted.Theresultsshowthatthelowmolecularweightoforganicacids(LMWOAs,i.e.,oxalic,tartaric,malicandcitricacids)andfulvicacidssigni?-cantlyacceleratedthedissolutionofFeandMn;inaddition,whentheconcentrationofOAreached25mmolL-1,theconcentrationsofFe,andMnwere1.14–67.08and1.11–2.32timesashighasthosein0.5mmolL-1OA,respectively.Furthermore,themigrationofFeandMnwassigni?cantlyin?uencedbythepHandEh,especiallyforFe;theionMnwasdissolvedfromtheganguemoreeasilythantheionFeinthecolumnleaching,whichwascontrarytotheresultsofbatchleaching.
简介:EffectofLa-richrareearthoneutecticmicrostructureinA1-2%Fealloywasstudied.WhentheadditionofREissmall,a-A1phaseisintheformofcellulardendrite.WiththeincreaseoftheadditionofRE,thenucleationandgrowthofa-A1dendritearesuppressed,andeutecticAl3Fephaseisrefined.WhentheadditionofREgetsto0.6%(massfrac-tion),thesizeofeutecticAl3Feincreases.Inaddi-tion,mechanismoftheeffectofmixedREoneutecticmorphologyofA1-2%Fealloyisexplored.
简介:Evaluationofthesound-structureinteractionisimportantforeffectivecontrolofnoiseandvibrationinstructuralacousticsystems.Crackedelasticstructure-soundinteractionproblemsarestudiedbyemployingthehybridfractalFEMandBEM.ThedegreesoffreedomofthesystemcanbereducedgreatlythroughadoptingfractalFEMindiscretizingthecrackedelasticstructure;whiletheexterioracousticfieldiscalculatedbyBEM,whichautomaticallysatisfiesSommerfeld'sradiationcondition.Numericalexamplesaregivenandshowthattheresonantfrequenciesofthestructure-acousticcoupledsystemdecreaseasthedepthofthecrackincreases,andthatthecrackhasasignificanteffectontheacousticalfieldinthevicinityofthecracktip.
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.
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