简介：

简介：Apredator-preysystemwithaconstantproportionofpreyrefugeandstage-structureforpreyspeciesisproposedandstudiedinthispaper.Asetofconditionsforthepermanenceofthesystemisobtained.Thelocalstabilityofthesystemisdiscussedbythesignofeigenvalues.Furthermore,byusingtheiterativemethod,somesuitablesufficientconditionsfortheglobalattractivityoftheinteriorequilibriumisobtained.Ourstudyshowsthattheconstantproportionofpreyrefugecouldleadtomorecomplicatedynamicbehaviors.Numericalsimulationsarealsopresentedtoillustratethefeasibilityofthemainresults.

简介：NanosizedGa-containingZSM-5zeoliteswerepreparedviaisomorphoussubstitutionandimpregnationfollowedbycharacterizedusingvarioustechniques.Thecatalyticperformanceofthezeolitesforthearomatizationof1-hexenewasinvestigated.TheresultsindicatethatisomorphoussubstitutionpromotestheincorporationofGaheteroatomsintotheframeworkalongwiththeformationofextra-frameworkGaO+species（[GaO+]a）thathavestrongerinteractionswiththenegativepotentialoftheframework.Inaddition,basedonthePy-IRresultsandcatalyticperformance,the[GaO+]aspecieswithstrongerLewisacidsitesproducedabettersynergismwithmoderateBr?nstedacidsitesandthusimprovedtheselectivitytoaromaticcompounds.However,theimpregnationresultsintheformationofGa2O3phaseandsmallamountsofGaO+speciesthataremainlylocatedontheexternalsurface（[GaO+]b）,whichcontributetoweakerLewisacidsitesduetoweakerinteractionswiththezeoliteframework.During1-hexenearomatization,thenanosizedGaisomorphouslysubstitutedZSM-5zeolitesamples（Gax-NZ5）exhibitedbettercatalyticperformancecomparedtotheimpregnatedsamples,andthehighestaromaticyield（i.e.,65.4wt%）wasachievedovertheGa4.2-NZ5sample,whichcontainedwiththehighestGacontent.