简介:Fe/C-basedmagneticallyactivatedcarbon(MAC)wasobtainedbycarbonizingandactivatingitsprecursor,thatwaspreparedbyco-precipitationofanthracitecoalimpregnatedinferricchloridesolution.TheeffectoftheconcentrationsofFeCl3andpHofsolutiononBETsurfacearea,porevolumeandmagneticpropertiesoftheMACwasstudiedbyBETN2adsorptionandVSMmethod.TheresultsindicatedthatthemagnetizationofMACgraduallyincreaseswithincreasingconcentrationofFeCl3andpHvalueofsolution,andBETsurfaceareawasinclinedtofluctuation.ThelargestBETsurfaceareaandmagnetizationofMACwere1327.5m2/gand35.56emu/g,respectively.TheformofmagneticmatterinthemagneticallyactivatedcarbonwasmainlyFe3CbyX-raypowderdiffraction(XRD)andmagneticattractiontest.
简介:Inordertoimprovethehemostaticeffectivenessofethamsylateintreatmentofuppergastrointestinalhemorrhage,wehaddevelopedanewtypeofhemostaticdrug-oralandmagneticallycontrolledethamsylatemicrospheres(abbreviation:theetham-sylatemicrospheres)andtestedtheirparametersassociatedwithphysicalandchemi-calrespects.Itsmaincharacteristicsthatwefoundwere:1>Theethamsylatemi-
简介:Amorphousnickelbasedalloycatalysts(denotedastheSRNAseriescatalysts)werepreparedviarapidquenchingmethodfollowedbyalkalileachingandotheractivationprocedures.Thephysicochemicalcharacterizationsshowthatnickel,theactivecomponentinthesecatalysts,existsintheamorphousstate,andthecatalystparticlespossessmanynanosizedvoidsleadingtolargesurfacearea(thehighestis145m2/g).TheevaluationresultsinsomemodelreactionsshowthattheSRNAseriescatalystshave2to4timeshigheractivityandselectivitythanconventionalRaneyNicatalystforthehydrogenationofcompoundswithunsatur-atedfunctionalgroups.Atpresent,theSRNAseriescatalystshavebeensuccessfullyusedinhydrogenationofglucose,hydrogenationofpharmaceuticalintermediatesandpurificationofcaprolactam.Inordertousethesecatalystsefficiently,amagneticallystabilizedbed(MSB)technologyhasbeendevelopedbycombiningtheferromagneticpropertyofthecatalystwiththegoodmasstransfercharacteristicsofMSB.ThedemonstrationunitofMSBhydrogenationtechnologyhasbeensetupandhaskeptrunningfor2800hours.Theresultsshowthat,afterrunning2800hours,thecatalyststillretainedgoodactivity;meanwhile,thehydrogenationeffi-ciencyhadbeenimproved10timesincomparisonwiththetraditionalCSTRprocess.
简介:Experimentalstudyofanairliftwithamagneticallystabilizedbedintheriserbottomhasbeenperformed.Externalmagneticfieldallowseasycontrolofmagnetizedbedstructureandliquidcirculationrate.Minimumstabilizationandfluidizationconditionshavebeendeterminedexperimentallyandbyathree-linegraphicalmethod.Semi-empiricaldatacorrelationsofsectionsoftheexperimentalcurveshavebeenperformed.Scalingrelationshipsknownfromnon-magneticairliftareapplicabletoo,butwiththeassumptionthatthemagneticfieldaffectstheloopfrictioncoefficientonly.
简介:BasedontheFloquettheoryonordinarydifferentialequationswithperiodicallyvariablecoefficientsandthebifurcationapproachtononlinearequations,anumericalapproachtodeterminingthestabilityregionofcontrolparametersisestablishedforadynamiccontrolsystemcomposedofamovingbodylevitatedmagneticallyoverflexibleguideways.Thesystemisnonlinearlycoupledamongtheelasticdeformationofguideways,disturbancethelevitationpositionofthebodyandelectromagneticcontrolforces.Thenumericalsimulationisgivenforthesysteminthecaseinwhichthecontrolparametersaretakenwithinandoutofthestabilityregionrespectively.Resultsshowthatthisapproachisreliable.
简介:Amagneticallystabilizedbed(MSB)reactorforselectivehydrogenationofolefinsinreformatewasdevelopedbycombiningtheadvantagesofMSBandamorphousnickelalloycatalyst.Theeffectsofoperatingconditions,suchastemperature,pressure,liquidspacevelocity,hydrogen-to-oilratio,andmagneticfieldintensityonthereactionwerestudied.AmathematicalmodelofMSBreactorforhydrogenationofolefinsinreformatewasestablished.Areformingflowschemewithapost-hydrogenationMSBreactorwasproposed.Finally,MSBhydrogenationwascomparedwithclaytreatmentandconventionalpost-hydrogenation.
简介:Takingα-FeandNd2Fe14Bgrainsasexample,thegrainsizedependenceoftheexchange-couplinginteractionandeffectiveanisotropyandalsotheirvariationsdependingontheratioofmagneticallysoftandhardgrainsizes,Ds∶Dh,wereinvestigated.WhengrainsizeD>Lex,thegrain'sanisotropyisthestatisticvalueofthecoupledanduncoupledpart.TheanisotropyconstantofuncoupledpartisthecommonvalueK1andthatofcoupledpartvarieswiththedistancetothegrainsurface.Theeffectiveanisotropyconstantbetweenmagneticallysoftandhardgrains,Keff,canbeexpressedasthesumoftheproductsofvolumefractionsforsoftandhardgrains,respectively,andthecorrespondingmeananisotropyconstants.Thecalculationresultsindicatethattheexchange-couplinginteractionisenhancedwiththereductionofgrainsize,andtheeffectiveanisotropydecreaseswithreducinggrainsizeandincreasingratioofDs∶Dh.Inordertogethigheffectiveanisotropyconstant,Keff,incompositemagneticallysoft-hardgrains,thehardgrainsizeshouldbelargerthan30nmandthesoftgrainsizeshouldbeabout10nm.
简介:Liquid-solid(L-S)masstransfercoefficients(Ks)werecharacterizedinagas-liquid-solid(G-L-S)three-phasecountercurrentmagneticallystabilizedbed(MSB)usingamorphousalloySRNA-4asthesolidphase.Effectsofsuperficialliquidvelocity,superficialgasvelocity,magneticfieldstrength,liquidviscosityandsurfacetensionwereinvestigated.ExperimentalresultsindicatedthattheexternalmagneticfieldincreasedKsinthree-phaseMSB,ascomparedtothoseinconventionalG-L-Sfluidizedbeds;thatKsincreasedwithmagneticfieldstrength,superficialgasandliquidvelocitiesanddecreasedwithliquidviscosityandsurfacetension;andthatKsshoweduniformaxialandradialdistributionsexceptforsmallincreasesclosetothewall.DimensionlesscorrelationswereestablishedtoestimateKsoftheG-L-ScountercurrentMSBusingSRNA-4catalyst,withanaverageerrorof3.6%.