简介:Weproposeasingle-stepimplementationofamuti-target-qubitcontrolledphasegatewithonecatstatequbit(cqubit)simultaneouslycontrollingn—1targetcqubits.Thetwologicstatesofac.qubitarerepresentedbytwoorthogonalcatstatesofasinglecavitymode.Inthisproposal,thegateisimplementedwithnmicrowavecavitiescoupledtoasuperconductingtransnionqutrit.Becausethequtritremainsinthegroundstateduringthegateoperation,decoherencecausedduetothequtrit5senergyrelaxationanddephasingisgreatlysuppressed.Thegateimplementationisquitesimplebecauseonlyasingle-stcpoperationisneededandneitherclassicalpulsenormeasurementisrequired.Numericalsimulationsdemonstratethathigh-fidelityrealizationofacontrolledphasegatewithonecqubitsimultaneouslycontrollingtwotargetcqubitsisfeasiblewithpresentcircuitQEDtechnology.Thisproposalcanbeextendedtoawiderangeofphysicalsystemstorealizetheproposedgate,suchasmultiplemicrowaveoropticalcavitiescoupledtoanaturalorartificialthree-levelatom.
简介:Forsyngasproduction,thecombustionoffossilfuelsproduceslargeamountsofCO2asagreenhousegasannuallywhichintensifiesglobalwarming.Inthisstudy,chemicalloopingcombustion(CLC)hasbeenutilizedfortheeliminationofCO2emissiontoatmosphereduringsimultaneoussyngasproductionwithdifferentH2/COratioinsteamreformingofmethane(SR)anddryreformingofmethane(DR)inaCLC-SR-DRconfiguration.InCLC-SR-DRwith184reformertubes(similartoanindustrialscalesteamreformerinZagrosPetrochemicalCompany,Assaluyeh,Iran),DRreactionoccursoverRh-basedcatalystsin31tubes.Also,SRreactionishappenedoverNi-basedcatalystsin153tubes.CLCviaemploymentofMn-basedoxygencarrierssuppliesheatforDRandSRreactionsandproducesCO2andH2Oasrawmaterialssimultaneously.AsteadystateheterogeneouscatalyticreactionmodelisappliedtoanalyzetheperformanceandapplicabilityoftheproposedCLC-SR-DRconfiguration.Simulationresultsshowthatcombustionefficiencyreached1attheoutletoffuelreactor(FR).Therefore,pureCO2andH2OcanberecycledtoDRandSRsides,respectively.Also,CH4conversionreached0.2803and0.7275attheoutletofSRandDRsides,respectively.Simulationresultsindicatethat,3223kmolh-1syngaswithaH2/COratioequalto9.826wasproducedinSRsideofCLC-SR-DR.Afterthat,1844kmolh-1syngaswithaH2/COratioequalto0.986wasachievedinDRsideofCLC-SR-DR.ResultsillustratethatbyincreasingthenumberofDRtubesto50tubesandconsidering184fixedtotaltubesinCLC-SR-DR,CH4conversionsinSRandDRsidesdecreased2.69%and3.31%,respectively.However,thissubjectcausedtotalsyngasproductioninSRandDRsides(inallof184tubes)enhanceto5427kmolh-1.Finally,thermalandmolarbehaviorsoftheproposedconfigurationdemonstratethatCLC-SR-DRisapplicableforsimultaneoussyngasproductionwithhighandlowH2/COratiosinanenvironmentalfriendlyprocess.
简介:Chemicalloopingdryreforming(CLDR)isaninnovativetechnologyforCO2utilizationusingthechemicalloopingprinciple.TheCLDRprocessconsistsofthreestages,i.e.CH4reduction,CO2reforming,andairoxidation.Spinelnickelferrite(NiFe2O4)waspreparedanditsmulti-cycleperformanceasanoxygencarrierforCLDRwasexperimentallyinvestigated.X-raydiffraction(XRD)andLaserRamanspectroscopyshowedthatapurespinelcrystallinephase(NiFe2O4)wasobtainedbyaparallelflowco-precipitatingmethod.NiFe2O4wasreducedintoFe-Nialloyandwustite(FexO)duringtheCH4reductionprocess.SubsequentoxidationofthereducedoxygencarrierwasperformedwithCO2asanoxidanttoformanintermediatestate:amixtureofspinelNi1-xFe2+xO4,Fe2+yO4andmetallicNi.AndCOwasgeneratedinparallelduringthisstage.Approximate185mLofCOwasgeneratedfor1gspinelNiFe2O4inasinglecycle.TheintermediateoxygencarrierwasfullyoxidizedintheairoxidationstagetoformamixtureofNi1+xFe2-xO4andFe2O3.Althoughtheoriginalstateofoxygencarrier(NiFe2O4)wasnotfullyregeneratedandagglomerationwasobserved,agoodrecyclabilitywasshownin10successiveredoxcycles.更多还原
简介:Oxygen-andnitrogen-functionalizedcarbonnanotubes(OCNTsandNCNTs)wereappliedasmetal-freecatalystsinselectiveolefinhydrogenation.AseriesofNCNTswassynthesizedbyNH3post-treatmentofOCNTs.Temperature-programmeddesorption,N2physisorption,Ramanspectroscopy,high-resolutiontransmissionelectronmicroscopyandX-rayphotoelectronspectroscopywereemployedtocharacterizethesurfacepropertiesofOCNTsandNCNTs,aimingatadetailedanalysisofthetypeandamountofoxygenandnitrogen-containinggroupsaswellassurfacedefects.Thegas-phasetreatmentsappliedforoxygenandnitrogenfunctionalizationatelevatedtemperaturesupto600Cledtotheincreaseofsurfacedefects,butdidnotcausestructuraldamagesinthebulk.NCNTsshowedaclearlyhigheractivitythanthepristineCNTsandOCNTsinthehydrogenationof1,5-cyclooctadiene,andalsotheselectivitytocyclooctenewashigher.Thefavorablecatalyticpropertiesareascribedtothenitrogen-containingsurfacefunctionalgroupsaswellassurfacedefectsrelatedtonitrogenspecies.Incontrast,oxygen-containingsurfacegroupsandthesurfacedefectscausedbyoxygenspeciesdidnotshowclearcontributiontothehydrogenationcatalysis.
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