简介：Multiphaseflowcontrolwithelectromagneticbraking(EMBr)iswidelyusedinthecontinuouscastingofsteelslabs.Thebasicaimoftheflowcontrolsystemoftheprocessistodelivermoltensteelfromtheladlethroughthetundish,uppertundishnozzle,slidegate,andsubmergedentrynozzleintothemoldregionwithminimaldefects.Thisrequirestheoptimizationofturbulencelevelsatameniscustoavoidbothanexcessivelyfastflow(whichcreateshighfluctuationsofthemeniscuslevelinadditiontoslagentrapment,surfacenonuniformities,andsurfacedefects)andinsufficientslowflow(whichleadstomeniscussolidification,inadequatefluxinfiltration,andsurfacedefects).Inthisstudy,aEulerian-LagrangianapproachisusedtoinvestigatetheeffectsofEMBrandArbubbleinjectiononthesurfaceflowvelocity.TheresultsshowthathighArinjectionratescanleadtoanincreaseinsurfacevelocity.

简介：Theneedformoreactiveandhydrothermallystablefluidcatalyticcracking(FCC)catalyststocombattheeffectofmetalcontaminantshasledtoanincreaseindemandforrareearthoxides.RareearthoxidesenhancecatalystactivityandpreventthelossofacidsitesduringtheFCCunitoperation,especiallywhenheavyresiduewithhighmetalcontentisusedasfeed.Inthispaper,areviewwascarriedouttoshowtheeffectsofrareearthelementsonthestructure,activity,andstabilityofFCCcatalysts.Also,theuseofrareearthelementsasvanadiumtrapswasanalyzedinconjunctionwiththemechanismofcatalystdeactivationbyvanadium.TheobjectivewastoelucidatetheinteractionofvanadiumspecieswiththezeolitecomponentoftheFCCcatalystsandtheroleofrareearthelementsincounteringthedeleteriouseffectsofvanadiumontheFCCcatalysts.

简介：Unsteadyfluidflowsandlevelfluctuationsinathinslabcontinuouscastingmouldhavesignificantinfluenceonproductquality.Inthisstudy,thephenomenaconcerningtransientflowfeaturesandfreesurfacemotionswereanalyzedbymeansofthelargeeddysimulation(LES)softwarewiththesmagorinskySGSmodel-VisualCast(VCast)II,wheretheSimpleralgorithmonabody-fittedmeshwasusedtoresolvegoverningequations.Aseriesofwateranalogexperimentsonthefluidflowandthesurfacewaveinthemouldsofthinslabcontinuouscastingwerealsoperformed.Theresultsoffluidregions,middleofvortexandlevelfluctuationfromdigitalsimulationswereidenticalwiththeresultsofthewateranalogexperiments.

简介：Thisstudyestablishedathree-dimensionalmathematicalmodeltodeterminethefluidflowinaslabcontinuouscastingmoldunderanelectromagneticstirringforce.Theflowstructureanddistributionwerestudiedwithrespecttodifferentcontinuouscastingparametersandstirringcurrent.Basedonthecalculationresults,themoldfluxentrapmentindexinfreesurfaceandvelocityuniformityindexwereusedtoevaluatetheflowfieldinthemold.Thetheoreticalbasisfortheoptimizationoftheflowfieldstructurewasprovided.Thestudyalsosuggestedanoptimizationmethodforelectromagneticstirringparameters.

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简介：Intwin-rollstripcastingprocess,transportphenomenaoffluidinthemoltenpooldirectlyaffecttheprocessstabilityandthequalityofproducts.Inordertoelucidatethefundamentaltransportphenomenaintwin-rollcasting,acommercialsoftwarecalledProCASTwasemployedtosimulatethetransientfluidflowandlevelprofilebehaviorsduringtheearlystageoftheprocessinthisstudy.Thecoupledsetofgoverningdifferentialequationsformass,momentumandenergybalanceweresolvedwiththefiniteelementmethodandthetransientfreesurfaceproblemwastreatedwithavolumeoffluids(VOF)approach.Theeffectofdifferentdeliverysystemsconfigurationonflowpattern,levelprofileinthepoolwasstudiedandanalyzedinthispaper.Thenewwedgemetaldeliverysystemshavebeenoptimizedforthetwin-rollstripcaster.Itwasshownthatnewtypemetaldeliverysystemshadapreferableeffectontheuniformdistributionoffluidandlevelfluctuationinthepool.Thesimulationresultsalsoprovideavaluablebasisfortheoptimizationofdeliverysystemandprocessparametersduringtheinitialpouringstage.

简介：Anon-linecontrolmethodofsurfacequalityforcontinuoushot-dipgalvanizedsteelstripaftercoolingispresented,whichcombinesanalyticaldynamicstheoryofathinplatewiththefiniteelementmethod.Theinherentcharacteristicsofthenon-immersedandpartiallyimmersedstripinliquidzincwerecalculatedonthebasisoftheoreticalanalysisandnumericalsimulation,respectively.Multi-parameterfittingofthedeviationbetweenresultsusingdifferentmethodswasperformed.Tooptimizethestripexcitationfrequencyawayfromtheresonanceregion,on-linevibrationcontrolofthestripneartheairknifeunderfullproductconditionswasachievedbychangingthefieldproductionparametersbasedonthefieldtestresults.Theresultsindicatethatalthoughtheaxialvelocityhaslittleeffectontheinherentcharacteristicsofthestripcomparedwithothermanufacturingparameterssuchasthesteelspecificationsandtension,itinducesexternalexcitations,includingmovingtheaerodynamicloadandbearingvibration.Tosomedegree,thevibrationneartheairknifecanbereducedbystrengtheningthesupportstiffnessofthecontactrolls.Atotalon-linecontrolprogramofsurfacequalityforcontinuoushot-dipgalvanizedpureZnandgalvannealedsteelsheetinthecoolingsectionisproposed.

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简介：尽管目前在国有企业改革过程中还面临种种问题，但国务院国有资产监督管理委员会主任李荣融仍表示，过去一年国有企业改革继续深化，在一些重点难点问题上实现了四大突破。

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简介：2004年Inco公司共生产了精炼镍23．7万t，超过了历史最高纪录——1974年的23．2万t。全年铂族金属的产量为42．2万盎司，铜产量为12．4万t，是1994年安大略冶炼厂扩大铜产量以来的最高水平。

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