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简介：InthispaperweusedMOF-5andCu3(BTC)2toseparateCO2/CH4andCH4/N2mixturesunderdynamicconditions.Bothmaterialsweresynthesizedandpelletized,thusallowingforameaningfulcharacterizationinviewofprocessscale-up.ThematerialswerecharacterizedbyX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM).Byperformingbreakthroughexperiments,wefoundthatCu3(BTC)2separatedCO2/CH4slightlybetterthanMOF-5.BecausethecrystalstructureofCu3(BTC)2includesunsaturatedaccessiblemetalsitesformedviadehydration,itpredominantlyinteractedwithCO2moleculesandmoreeasilycapturedthem.Conversely,MOF-5withasuitableporesizeseparatedCH4/N2moreefficientlyinourbreakthroughtest.

简介：ThreeseriesofCeO2/CuOsampleswerepreparedbyimpregnationmethodandcharacterizedbyXRD,N2adsorption-desorption,temperatureprogrammedreduction(TPR),XPSandTEMtechniques.IncomparisonwiththesamplespreparedwithCuOasinitialsupport,thesampleswithCu(OH)2asinitialsupporthavehigherreducibilitiesandsmallerrelativeTPRpeakareas,andalsolargerspecificsurfaceareasatcalcinationtemperaturesof400℃–600℃.Asaresult,Cu(OH)2isbetterthanCuOasinitialsupportforpreferentialoxidationofCOinexcessH2(CO-PROX).Thebestcatalyticperformancewasachievedonthesamplecalcinedat600℃andwithanatomicratioofCe/Cuat40%.XPSanalysesindicatethatmoreinterfacelinkagesCe-O-Cucouldbeformedwhenitwascalcinedat600℃.AndtheatomicratioofCe/Cuat40%ledtoaproperreducibilityforthesampleasillustratedbytheTPRmeasurements.

简介：QuantumdynamicscalculationsforthetitlereactionH(2S)+S2(X3-Σg)→SH(X2Π)+S(3P)areperformedbyusingagloballyaccuratedoublemany-bodyexpansionpotentialenergysurface[J.Phys.Chem.A1155274(2011)].TheChebyshevrealwavepacketpropagationmethodisemployedtoobtainthedynamicalinformation,suchasreactionprobability,initialstate-specifiedintegralcrosssection,andthermalrateconstant.Itisfoundnotonlythatthereisareactionthresholdnear0.7eVinbothreactionprobabilitiesandintegralcrosssectioncurves,butalsothatboththeprobabilityandcrosssectionincreasefirstlyandthendecreaseasthecollisionenergyincreases.Theexistenceoftheresonancestructureinboththeprobabilityandcrosssectioncurvesisascribedtothedeeppotentialwell.Thecalculationoftherateconstantrevealsthatthereactionoccurringonthepotentialenergysurfaceoftheground-stateHS2isslowtotakeplace.

简介：AnewSnO_2-Fe_2O_3/SWCNTs(single-walledcarbonnanotubes)ternarynanocompositewasfirstsynthesizedbyafacilehydrothermalapproach.SnO_2andFe_2O_3nanoparticles(NPs)werehomogeneouslylocatedonthesurfaceofSWCNTs,asconfirmedbyX-raydiffraction(XRD),transmissionelectronmicroscope(TEM)andenergydispersiveX-rayspectroscopy(EDX).Duetothesynergisticeffectofdifferentcomponents,theassynthesizedSnO_2-Fe_2O_3/SWCNTscompositeasananodematerialforlithium-ionbatteriesexhibitedexcellentelectrochemicalperformancewithahighcapacityof692mAh·g~(-1)whichcouldbemaintainedafter50cyclesat200mA·g~(-1).Evenatahighrateof2000mA·g~(-1),thecapacitywasstillremainedat656mAh·g~(-1).

简介：Thereisagrowingsupportforthelowlyingscalarmesonsf0(500),f0(980),a0(980),and(800)tobegenerateddynamicallyfromtheinteractionofpseudoscalarmesons,whilethecaseofthenextsetofscalarresonancesathigherenergies,f0(1370),f0(1710),K0(1430)ismoreaquestionofdebate.Soisthecaseofthetensorresonancesf2(1270),f′2(1525),K2(1430).AnewperspectiveonthesestateshasbeenofferedinRef.[1]wherethef0(1370)andf2(1270)resonancesareshowntobegeneratedfromtheinteractionprovidedbythelocalhiddengaugeLagrangiansimplementingunitarization.Itisshownthattheideaofthenatureofthesestatesasvectormeson-vectormesoncompositestateshasbeentestedinmanyreactions.Yet,thepermanentdiscussionoftheissuedemandsextrachecksforotherobservablesand,inthissense,theweakdecaysbringanewsourceofvaluableinformationthatshouldservetotestdifferentmodels.

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简介：Nanostructuredγ-Al2O3withhighsurfaceareaandmesoporousstructurewassynthesizedbysol-gelmethodandemployedascatalystsupportfornickelcatalystsinmethanereformingwithcarbondioxide.ThepreparedsampleswerecharacterizedbyXRD,N2adsorption-desorption,TPR,TPO,TPH,NH3-TPDandSEMtechniques.TheBETanalysisshowedahighsurfaceareaof204m2g-1andanarrowpore-sizedistributioncenteredatadiameterof5.5nmforcatalystsupport.TheBETresultsrevealedthatadditionoflanthanumoxidetoaluminumoxidedecreasedthespecificsurfacearea.Inaddition,TPRresultsshowedthatadditionoflanthanumoxideincreasedthereducibilityofnickelcatalyst.Thecatalyticevaluationresultsshowedanincreaseinmethaneconversionwithincreasinglanthanumoxideto3mol%andfurtherincreaseinlanthanumcontentdecreasedthecatalyticactivity.TPOanalysisrevealedthatthecokedepositiondecreasedwithincreasinglanthanumoxideto3mol%.SEMandTPHanalysesconfirmedtheformationofwhiskertypecarbonoverthespentcatalysts.AdditionofsteamandO2todryreformingfeedincreasedthemethaneconversionandledtocarbonfreeoperationincombinedprocesses.

简介：Nucleon-nucleon(NN)correlationsandtheirisospindependenceinasymmetricnuclearmatterareofgreatnterestsincetheyarecloselyrelatedtothestructureofneutron-richnuclei[1],particleproductioninheavy-ionollisions[2],andneutron-starphysics[3].Themany-bodycorrelationsamongnucleonscanbedirectlyreflectedintheneutronandprotonspectralfunctions[4],andthelattermayplayanimportantroleinunderstandingthenatureftheNNcorrelations,especiallytheshort-rangeandtensorcorrelationsinasymmetricnuclearmatter.

简介：Inthisstudy,apoly(etherblockamide)(Pebax1657)compositemembraneappliedforCO2capturewaspreparedbycoatingPebax1657solutiononpolyacrylonitrile(PAN)ultrafiltrationmembrane.Ethanol/watermixturewasusedasthesolventofPebaxandtheeffectsofethanol/watermassratiosandPebaxconcentrationonthepermeationpropertiesofcompositemembranewerestudied.Toenhancethecompositemembranepermeance,thegutterlayer,madefromreactiveaminosiliconecrosslinkingwithpolydimethylsiloxane(PDMS),wasdesigned.Theinfluenceofcrosslinkingdegreeofthegutterlayeronmembraneperformancewasinvestigated.Asaresult,aPebax/aminoPDMS/PANmultilayermembranewithhexaneresistancewasdeveloped,showingCO2permeanceof350GPUandCO2/N2selectivityover50.Theblendofpolyethyleneglycoldimethylether(PEG-DME)withPebaxascoatingmaterialwasstudiedtofurtherimprovethemembraneperformance.AfterbeingcombinedwithPEG-DMEadditive,CO2permeanceofthefinalPebax-PEG-DME/amino-PDMS/PANcompositemembranereached400GPUabovewithCO2/N2selectivityover65.

简介：Weprovideanewclassofinteriorsolutionofa(2+1)-dimensionalanisotropicstarinFinchandSkeaspacetimecorrespondingtotheBTZblackhole.WedevelopthemodelbyconsideringtheMITbagmodelEOSandaparticularansatzforthemetricfunctiongrrproposedbyFinchandSkea[M.R.FinchandJ.E.F.Skea,Class.Quantum.Grav.6(1989)467].Ourmodelisfreefromcentralsingularityandsatisfiesallthephysicalrequirementsfortheacceptabilityofthemodel.

简介：MoleculardynamicssimulationsareperformedtostudythegrowthmechanismofCH4-CO2mixedhydrateinxCO2=75%,xCO2=50%,andxCO2=25%systemsatT=250K,255Kand260K,respectively.OursimulationresultsshowthatthegrowthrateofCH4-CO2mixedhydrateincreasesastheCO2concentrationintheinitialsolutionphaseincreasesandthetemperaturedecreases.Viahydrateformation,thecompositionofCO2inhydratephaseishigherthanthatininitialsolutionphaseandtheencagingcapacityofCO2inhydratesincreaseswiththedecreaseintemperature.ByanalysisofthecageoccupancyratioofCH4moleculesandCO2moleculesinlargecagestosmallcages,wefindthatCO2moleculesarepreferablyencagedintothelargecagesofthehydratecrystalascomparedwithCH4molecules.Interestingly,CH4moleculesandCO2moleculesfrequentlyreplacewitheachotherinsomeparticularcagesitesadjacenttohydrate/solutioninterfaceduringthecrystalgrowthprocess.Thesetwospeciesofguestmoleculeseventuallyacttostabilizethenewlyformedhydrates,withCO2moleculesoccupyinglargecagesandCH4moleculesoccupyingsmallcagesinhydrate.

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简介：Wereportedabifunctionalmaterial,Cr-salenimplantedconjugatedmicroporouspolymer(Cr-CMP),whichisabletocaptureexcellentCO2amountsandhasaremarkablecatalyticactivitytowardsthecycloadditionreactionofCO2toepoxidesformingcycliccarbonatesatmildconditionswithoutadditionalsolvents.ThisheterogeneousCr-CMPcatalysthasasuperiorcatalyticactivitytoitsrelatedhomogeneouscatalystandcanbereusedmorethantentimeswithoutasignificantdecreaseincatalyticactivity.

简介：ThespectrumoftheΣ(1193)excitedstates,Σ,withisospinI=1andstrangenessS=??1isoneofthemostimportantissuesinhadronicphysics.TheΣresonancesaremostlyproducedandstudiedinK-inducedreactions.ManyΣresonancesarenowcatalogedbytheParticleDataGroup[1].However,ourknowledgeoftheseresonancesisstillverypoor.Intheenergyregionbelow2GeV,onlyafewofthemarewellestablished,suchastheΣ(1385)ofspin-parityJP=3=2+,Σ(1670)ofJp=3=2??andΣ(1775)ofJp=5=2??.Theothersarenotwellestablishedandsomeofthemareevenoflargeuncertaintiesontheirexistence.Thus,thestudyoftheΣresonancewiththeavailableexperimentaldataisnecessary.

简介：研究目的：研究新型磁性回热填料Gd2O2S对液氦温区高频脉管制冷机多级回热器损失特性的影响。创新要点：确定了不同回热填料以及运行参数（频率、平均压力）下液氦温区多级脉管制冷机的制冷温度和各级预冷量，进一步明确了4K高频回热损失机理。研究方法：采用理论研究与实验验证相结合的方法，基于一台两级G-M型低频脉管制冷机预冷的单极斯特林型高频脉管制冷机，研究多级回热器在高频以及4K温区下的损失特性。选取新型回热填料Gd2O2S替代部分回热填料HoCu2，比较回热器采用两种填料时在不吲运行频率及平均压力下的冷端制冷温度（图10）、各级预冷量和预冷温度（图1112）。重要结论：采用孔隙率较小的新型磁性回热填料Gd2O2S可显著改善第一级回热器内压力波与质量流的相位关系，从而减小该级回热损失。减小平均压力可以降低制冷机无负荷制冷温度并减小第二级预冷量，但制冷工质氦的体积比热容会急剧增大，从而使低温级回热器的换热对频率非常敏感。此外，频率对高温级回热器的回热特性影响不明显。该方法可以为三级斯特林型4K多级脉管制冷机提供设计依据。