简介:TheAl2O3-SiCcompositepowderswerepreparedinargonatmosphereusingcoalgangueandcarbonaceousmaterials
简介:Twooxo-vanadium(IV)complexes,[VO(C2O4)(2,2′-bipy)(H2O)]·C2H5OH(1)andVO(C2O4)(phen)(H2O)(2),where2,2′-bipy=2,2′-bipyridyl,phen=1,10-phenanthroline,weresynthesizedaspotentialfunctionalmodelsofvanadiumhaloperoxidases(VHPOs)inmixedsolventofethanolandwateratroomtemperature.Thecomplexeswerecharacterizedbyelementalanalysis,infrared(IR),UV-VisandX-raycrystallography.Structuralanalysesshowedthatvanadiumatomwascoordinatedbyaterminaloxygen,oneoxygenatomfromcoordinatedwater,twooxygenatomsfromthecarboxylategroupofoxalicacid,andtwonitrogenatoms(N1andN2)from2,2′-bipy/phen.Centralvanadiumatomsincomplexes1and2werebothinadistorted-octahedralenvironment,andsomeintermolecularhydrogenbondinglinkageswerealsoobservedineachcomplex.BrominationreactionactivityofthetwocomplexeswasevaluatedwithphenolredasorganicsubstrateinthepresenceofH2O2,Br-andphosphatebuffer,indicatingthattheycanbeconsideredasapotentialfunctionalmodelofVHPO.Inaddition,thermalanalysiswasalsoperformedanddiscussedindetail.
简介:Chemical-loopingcombustion(CLC)isanovelcombustiontechniquewithinherentCO2separation.Magnetite(Fe3O4)wasselectedastheoxygencarrier.Shenhuacoal(InnerMongolia,China),strawcokeandnaturalcokewereusedasfuelsforthisstudy.Influencesofoperationtemperatures,coaltoFe3O4massratios,anddifferentkindsoffuelsonthereductioncharacteristicsoftheoxygencarrierwereinvestigatedusinganatmospherethermogravimetricanalyzer(TGA).Scanningelectronmicroscopy(SEM)wasusedtoanalysethecharacteristicofthesolidresidues.Experimentalresultsshownthatthereactionbetweenthecoalandtheoxygencarrierbecomestrongatatemperatureofhigherthan800℃.Astheoperationtemperaturerises,thereductionconversionrateincreases.Atthetemperaturesof850oС,900℃,and950℃,thereductionconversionrateswere37.1%,46.5%,and54.1%respectively.However,SEMimagesshowthatatthetemperatureofhigherthan950℃,theironoxidesbecomemeltedandsintered.Thepossibleoperationtemperatureshouldbekeptaround900℃.WhenthemassratiosofcoaltoFe3O4were5/95,10/90,15/85,and20/80,thereductionconversionrateswere29.5%,40.8%,46.5%,and46.6%respectively.Withtheincreaseofcoal,theconversionrategoesup.Butthereexistanoptimalratioaround15/85.Comparisonsbasedondifferentkindsoffuelsshowthatthesolidfuelwithahighervolatileandamoredevelopedporestructureisconducivetothereductionreactivityoftheoxygencarrier.
简介:SYNTHESIS AND 183W NMR CHARACTERIZATION OF P4W30Al4(H2O)2O11220- HETEROPOLYANIONSYNTHESISAND183WNMRCHARACTERIZ?..
简介:本文报道了C6H12O6(NH4)2SO4C2H5OHH2O(C2H5OH/H2O=0.90)体系在35℃时体系溶解度和饱和溶液的折光指数,并绘出了体系相应的溶度图和饱和溶液的折光指数曲线图。结果表明:所研究的体系为四元体系C6H12O6(NH4)2SO4C2H5OHH2O中的一部分。当溶液中肌醇饱和时,溶度曲线落在约50%的等醇水比面上。当(NH4)2SO4在溶液中达到饱和时,出现共饱点。其组成为(NH4)2SO4:210%,C6H12O6:2.08%,C2H5OH:4475%。同时出现分层,在富醇相随着乙醇浓度的增加,出现肌醇与硫酸铵共饱线。在富水相硫酸铵饱和溶度曲线落在约5%乙醇的等醇水比面上,折光指数曲线由三支组成,其中两条分别与C6H12O6·H2O和(NH4)2SO4相对应,另外一条线与(NH4)2SO4和C6H12O6·H2O的共饱线相对应
简介:用扫描电镜、X-射线衍射、等离子体原子发射光谱、热重分析、循环伏安、恒电流充放电、交流阻抗法研究了溶胶-凝胶法合成的尖晶石锂锰氧化物的物理化学性能,并与熔盐法合成样品作了比较.熔盐法制备的样品的颗粒为不规则块状,初始容量低(99.6mAh/g),而溶胶-凝胶法制备样品的颗粒细小、均匀,初始容量较高(112.5mAh/g).但是熔盐法制备的样品经30次循环后容降为15%,而溶胶-凝胶的却高达40%.熔盐法制备的样品中实际Li/Mn为0.506,与原料中Li/Mn摩尔比相近,而溶胶-凝胶法只有0.473,比原料中的小.熔盐法制备的样品为纯尖晶石结构,而溶胶-凝胶法制备的有杂相Mn2O3生成.热处理过程中部分Li的挥发损失和非电化学活性Mn2O3的生成导致锂锰氧化物容量快速下降.
简介:Theoccurrencemodesofalkaliandalkaline-earthmetals(AAEMs)incoalrelatetotheirreleasebehaviorandashformationduringcombustion.TobetterunderstandthetransformationofAAEMs,thereleasebehaviorofwater-soluble,HCl-soluble,HCl-insolubleAAEMsduringShenmucoal(SMcoal)oxy-fuelcombustioninthepresenceofSO2andH2Oinadrop-tubereactorwasinvestigatedthroughserialdissolutionusingH2OandHClsolutions.TheresultsshowthatthereleaseratesofAAEMsincreasewithanincreaseintemperatureunderthethreeatmospheresstudied.ThehighreleaseratesofMgandCafromSMcoalaredependentonthehighcontentofsolubleMgandCainSMcoal.SO2inhibitsthereleaseratesofAAEMs,whileH2Opromotesthem.TheeffectsofSO2andH2OontheNaandKspeciesaremoreevidentthanthoseonMgandCaspecies.AllthreetypesofAAEMsincoalcanvolatilizeinthegasphaseduringcoalcombustion.TheW-typeAAEMsreleaseexcessively,whereasthereleaseratesofI-typeAAEMsarerelativelylower.DifferenttypesofAAEMmayinterconvertthroughdifferentpathwaysundercertainconditions.BothSO2andH2Opromotethetransformationreactions.TheeffectofSO2wasrelatedtosulfateformationandthepromotionbyH2OoccursbecauseofadecreaseinthemeltingpointofthesolidaswellasthereactionofH2O.
简介:WehavesynthesizedandinvestigatedphysicalpropertiesoftwonewquaternarycompoundsGd2CoAl4T2(T=Si,Ge)singlecrystals,whichareisostructuraltoTb2NiAl4Ge2andEr2CoAl4Ge2.Themostimportantstructuralfeatureofthesematerialsistheanti-CaF2-typeCoAl4T2slabs.Thesematerialsshowmetallicbehaviorbelow300Kandthereisalong-rangeantiferromagnetic(AFM)transitionappearingat20and27KforGdCoAl4Ge2andGd2CoAl4Si2,respectively.ResistivityandheatcapacitymeasurementsalsoconfirmthesebulkAFMtransitions.Furtheranalysisindicatesthatthislong-rangeantiferromagnetismshouldresultfromthemagneticinteractionbetweenlocalmomentsofGd^3+ions.
简介:Thecombinationofboth4,4′-bipyridine(4,4′-bipy)anddihydrogenphosphateanionligandswithcopper(Ⅱ)resultsintheformationofanovellayeredcompoundCu(4,4′-bipy)2(H2PO4)2(H2O)2.ThecrystalstructurecomprisesdiscreteneutralCu(4,4′-bipy)2(H2PO4)2(H2O)2units.Thecopperatom,locatedonthecrystallographictwofoldaxis,iscoordinatedwithtwonitrogenatomsofterminal4,4′-bipyligandsandtwowatermoleculesattheequatorialpositions,andtwodihydrogenphosphateoxygenatomsattheaxialpositions,forminganelongatedoctahedron.Thecomplexisatwo-dimensionaldistortedrhomboidalnetworkpossessingtwokindsofrhomboidswithdimensionsofca.1.6792nm×0.3203nmand1.2778nm×0.3198nm,respectively.Thetwo-dimensionalnetworksarestackedparallellyoneachotheralongc-axistogiveanextendedthree-dimensionalchannelnetworkwithaninterlayerdistanceofca.0.5030nm.Crystaldata:triclinic,spacegroupP-1,a=1.0253(2)nm,b=1.4501(3)nm,c=0.79715(16)nm,α=97.91(3)°,β=90.99(3)°,γ=85.54(3)°,V=1.1703(4)nm3,Z=2,R=0.0892,wR=0.2451.
简介:CO2methanationhasbeenahottopicbecauseofitsimportantapplicationinthespacecraftandpotentialutilizationofcarbondioxide.Nickelcatalystisactiveforthisreaction.However,itsactivitystillneedstobeimproved.Dielectricbarrierdischarge(DBD)plasma,initiatedatambientconditionandoperatedat~150°C,hasbeenemployedinthisworkfordecompositionofnickelprecursortoprepareNi/MgAl2O4.Theplasmadecompositionresultsinhighdispersion,uniquestructure,enhancedreducibilityofNiparticlesandpromotedcatalyst-supportinteraction.AnimprovedactivityofCO2methanationwithahigheryieldofmethanehasbeenachievedovertheplasmadecomposedcatalyst,comparedtothecatalystpreparedthermally.Forexample,themethaneyieldoftheplasmapreparedcatalystis71.8%at300°Cbutitis62.9%overthethermalpreparedcatalyst.ThecatalystcharacterizationconfirmedthatCO2methanationovertheDBDplasmapreparedcatalystfollowspathwayofCOmethanation.
简介:ElectrocrystallizationMechanismofTungsteninMoltenKF-B_2O_3-K_2WO_4WenZhenhuanandLiGuoxun文振环,李国勋(GeneralResearchInstiiuteforNo...