简介:Nanocarbonmaterialsplayacriticalroleinthedevelopmentofneworimprovedtechnologiesanddevicesforsustainableproductionanduseofrenewableenergy.Thisperspectivepaperdefinessomeofthetrendsandoutlooksinthisexcitingarea,withtheeffortofevidencingsomeofthepossibilitiesofferedfromthegrowinglevelofknowledge,astestifiedfromtheexponentiallyrisingnumberofpublications,andputtingbasesforamorerationaldesignofthesenanomaterials.Thebasicmembersofthenewcarbonfamilyarefullerene,graphene,andcarbonnanotube.Derivedfromthemarecarbonquantumdots,nanohorn,nanofiber,nanoribbon,nanocapsulate,nanocageandothernanomorphologies.Secondgenerationnanocarbonsarethosewhichhavebeenmodifiedbysurfacefunctionalizationordopingwithheteroatomstocreatespecifictailoredproperties.Thethirdgenerationofnanocarbonsisthenanoarchitecturedsupramolecularhybridsorcompositesofthefirstandsecondgenerationnanocarbons,orwithorganicorinorganicspecies.Theadvantagesofthenewcarbonmaterials,relatingtothefieldofsustainableenergy,arediscussed,evidencingtheuniquepropertiesthattheyofferfordevelopingnextgenerationsolardevicesandenergystoragesolutions.
简介:Inthemidseventiesanewpropulsorforaircraftwasdesignedandinvestigated-theso-calledPROPFAN.Withregardtothetotalpressureincrease,itrangesbetweenaconventionalpropellerandaturbofanwithveryhighbypassratio.Thisnewpropulsionsystempromisedareductioninfuelconsumptionof15to25%comparedtoenginesatthattime.Alotofpropfans(HamiltonStandard,USA)withdifferentnumbersofbladesandbladeshapeshavebeendesignedandtestedinwindtunnelsinordertofindanopimuminefficiency,Fig.1.ParalleltothisdevelopmentGE,USA,madeadesignofacounterrotatingunductedpropfan,theso-calledUDF,Fig.2.Aprototypeenginewasmanufacturedandinvestigatedonanin-flighttestbedmountedattheMD82andtheB727.Sincethattimetherehasnotbeenanyfurtherdevelopmentofpropfans(exceptAN70withNK90-engineUkraine,whichismoreorlessapropellerdesign)duetorelativelylowfuelpricesandtechnicalobstacles.Onlytechnicalprogramsindiferentcountriesarestillgoingoninordertoprepareadatabasefordesigningcounterrotatingfansintermsofaeroacoustics,aerodynamicsandaeroelasticities.InDLR.Germany,alotofexperimentalandnumericalworkhasbeenundertakentounderstandthephysicalbehaviouroftheunsteadyflowinacounterrotatingfan.
简介:Reversewatergasshift(RWGS)reactioncanbeservedasapivotalstageoftransitioningtheabundantCO2resourceintochemicalsorhydrocarbonfuels,whichisattractivefortheCO2utilizationandofeventuallysignificanceinenablingarebuiltecologicalsystemforunconventionalfuels.Thisconceptisappealingwhentheprocessisconsideredasasolutionforthestorageofrenewableenergy,whichmayalsofindavarietyofpotentialendusesfortheouterspaceexploration.However,abigchallengetothisissueistherationaldesignofhightemperatureendurableRWGScatalystswithdesirableCOproductselectivity.Inthiswork,wepresentacomprehensiveoverviewofrecentpublicationsonthisresearchtopic,mainlyfocusingonthecatalyticperformanceofRWGSreactionoverthreemajorkindsofheterogeneouscatalysts,includingsupportedmetalcatalysts,mixedoxidecatalystsandtransitionmetalcarbides.Thereactionthermodynamicanalysis,kineticsandmechanismsarealsodescribedindetail.Thepresentreviewattemptstoprovideageneralguidelineabouttheconstructionofwell-performedheterogeneouscatalystsfortheRWGSreaction,aswellasdiscussingthechallengesandfurtherprospectsofthisprocess.
简介:Thelittle-Higgsmodelstypicallycontainanewvector-liketopquarkT,whichplaysakeyroleinbreakingtheelectroweaksymmetry.InthecontextofthelittlestHiggs(LH)model,westudysingleproductionofthiskindofnewparticlesviatheprocessep→eb→veTinthefuturelinac-ring-typeepcollider(LCО×LHC).Wefindthattheproductioncrosssectionisintherangeof1.2×10^-40.48pbattheLCО×LHCwith√s=3.7TeV.