简介:13kindsofironores(6fromAustraliaand7fromBrazil)werestudiedontheirpropertiesconcerningCW(CombinedWater)decomposition,Fe2O3decompositionandsoftening-meltinginairatmospherethroughthecharacterizationmethodofTG-DSC(Thermogravimetry-DifferentialScanningCaloremetry).TheexperimentalresultsoftheAustralianoresandBrazilianoresdifferintermsoftheinitialtemperature,temperaturerangeandendothermicamountofCWdecomposition,andbesides,thecontentofCW.ItisestimatedthatforeverypercentincreaseofCWcontentinsinteringrawmaterial,theextrathermalamountabsorbedintheprocessisabout1.83×104kJ,whichequalstothethermalcapacityof0.625kgofstandardcoalburningupcompletely.AstothedecompositionofFe2O3,theinitialtemperatures,terminaltemperaturesandtemperaturerangesoftheAustralianandBrazilianoresarequiteclose.However,theendothermicamountofFe2O3decompositionofthetwoturnsoutratherdifferent:theendothermiccapacityofFe2O3decompositionoftheAustralianoresisgreaterthanthatoftheBrazilianores.Furthermore,theliquidamountgeneratedinthesoftening-meltingprocessiscloselyrelatedtotheSiO2contentinironore.ThehigherSiO2contenttheorecontains,themoreliquidvolumeitwillgenerateinthesoftening-meltingprocessofironore.
简介:梅赛德斯-奔驰携多款车型首发2011年日内瓦车展3月1日,梅赛德斯-奔驰多款新车盛装亮相日内瓦车展,印证了奔驰125年来在豪华车制造领域无可比拟的至高造诣。全球首发的C级轿跑车,与C63AMG高性能轿车、高性能旅行轿车同台登场。
简介:Thephotopolymerizationoftwokindsofprepolyesterscontainingconjugateddiacetylene(PDA-6andPDA-12)wasinvestigatedusingDSC.BymeasuringtheendothermicenthalpyoftheprepolymersafterdifferentUV-irradiationtimes,thepolymerizationswerefoundtofollowthefirst-orderratelawwhichagreedwiththeresultsofotherinvestigatorsusingadifferentmethod.TheendothermicenthalpymeasurementsofPDA-6andPDA-12beforeUV-irradiationprecludedthepossibilitythatthedecreaseofendothermicenthalpywascausedbythermalpolymerization.
简介:Themolecularstructureofpolyethylene(PE)sampleswithvariouscomonomersincludingpropylene,1-buteneand1-hexenewasinvestigatedbyDSCand13C-NMRtechniques.Thedensityofthesamplesvariesfrom0.948g/cm3to0.917g/cm3,andthemolecularweightdeterminedbytheGPCmethodisintherangeof1~2×105.Thebranchpointcontentofthesampleswasdeterminedby13C-NMRmeasurementsandwasfoundtobelessthan20per1000Catomsalongthemainchain.CrystallizationsegregationDSCtechnique(CSDSC)wasusedtocharacterizethebranchpointdistributionorthesegmentlengthdistributionofPEs.Thecrystallizationsegregationwasperformedinasuccessiveannealingprocessatdecreasingtemperatures.Theintervaloftwosuccessiveannealingtemperatureswas6K,andthetimelengthofeachannealingstepwas2.5h.TheCSDSCresultsclearlyindicatethatallthePEsamplesused,includingsomemetallocenePEs,moreorlessexhibittheirnon-uniformityinsegmentlengthdistribution,andbimodalormultimodalCSDSCcurveswereusuallyobserved.ForquantitativecharacterizationoftheCSDSCcurvesandthesegmentlengthdistributiontwoparameters,theaveragemeltingpoint,TmAV,andtheroot-mean-squaredeviationofmeltingtemperature,(ΔTmAV2)1/2,wereproposed.TmAViscorrespondingtotheaveragesegmentlengthduetobranchingand(ΔTmAV2)1/2givesinformationaboutthewidthofthesegmentlengthdistribution.Experimentalresultsshowthatboththedegreeofaveragemeltingtemperaturedepressionandthewidthofthedistributionseemtoincreasewithincreasingthebranchingcontentandaredependentonthetypeofcomonomers.VerygoodreproducibilityandadditivityoftheCSDSCmethodwereevidencedexperimentally.ItwasconcludedthattheCSDSCtechniqueisasensitiveandconvenientmethodforcharacterizingthesegmentlengthdistributionofbr