简介:Wepresentsecond-orderexpressionsforthefree-surfaceelevation,velocitypotentialandpressureresultingfromtheinteractionofsurfacewavesinwaterofarbitrarydepth.Whenthesurfacewaveshavenearlyequalfrequenciesandnearlyoppositedirections,asecond-orderpressurecanbefeltallthewaytotheseabottom.Thereareatleasttwoareasofapplications:reflectivestructuresandmicroseisms.Microseismsgeneratedbywaterwavesintheoceanaresmallvibrationsofthegroundresultingfrompressureoscillationsassociatedwiththecouplingofoceansurfacegravitywavesandtheseafloor.Theyarerecordedonland-basedseismicstationsthroughouttheworldandtheyaredividedintoprimaryandsecondarytypes,asafunctionofspectralcontent.Secondarymicroseismsaregeneratedbytheinteractionofsurfacewaveswithnearlyequalfrequenciesandnearlyoppositedirections.Theefficiencyofmicroseismgenerationthusdependsinpartonoceanwavefrequencyanddirection.Basedonthesecond-orderexpressionsforthedynamicpressure,asimpletheoreticalanalysisthatquantifiesthedegreeofnearnessinamplitude,frequency,andincidenceangle,whichmustbereachedtoobservethephenomenon,ispresented.
简介:Reversewatergasshift(RWGS)reactioncanbeservedasapivotalstageoftransitioningtheabundantCO2resourceintochemicalsorhydrocarbonfuels,whichisattractivefortheCO2utilizationandofeventuallysignificanceinenablingarebuiltecologicalsystemforunconventionalfuels.Thisconceptisappealingwhentheprocessisconsideredasasolutionforthestorageofrenewableenergy,whichmayalsofindavarietyofpotentialendusesfortheouterspaceexploration.However,abigchallengetothisissueistherationaldesignofhightemperatureendurableRWGScatalystswithdesirableCOproductselectivity.Inthiswork,wepresentacomprehensiveoverviewofrecentpublicationsonthisresearchtopic,mainlyfocusingonthecatalyticperformanceofRWGSreactionoverthreemajorkindsofheterogeneouscatalysts,includingsupportedmetalcatalysts,mixedoxidecatalystsandtransitionmetalcarbides.Thereactionthermodynamicanalysis,kineticsandmechanismsarealsodescribedindetail.Thepresentreviewattemptstoprovideageneralguidelineabouttheconstructionofwell-performedheterogeneouscatalystsfortheRWGSreaction,aswellasdiscussingthechallengesandfurtherprospectsofthisprocess.