简介:Theinfluencesofsilicavolumefraction,electrolyteconcentrationandpHvalueuponthestressdependenceofelasticmodulusG′andviscousmodulusG″wereinvestigated.Theresultsshowthatthesuspensiontransformsfromaliquid-likestatetoasolid-likestatewithincreasingthevolumefractionofsilica.Suchasolid-likestatecanbetransformedbackintoaliquid-likestateundertheapplicationofalargerstress.Atthehighervolumefraction,thelargercriticalstressisrequiredtoinducethetransitionfromsolid-liketoliquid-likestate.AstheelectrolyteconcentrationdecreasesorpHvalueincreases,theinter-particleforceincreases,whichcausesthestatetransitiontooccuratahigherstress.
简介:Sphere-likecompoundC8H17Si(OPhC12H25)3N(1)formsmesophases.Inordertoinvestigatetherelationshipbetweenmolecularstructureandliquidcrystalproperties,structuralstudiesarecarriedoutonthemodelmoleculesofcompound1anditssubstitutedderivativesusingahinitiocalculations.TheresultsshowthatthecyanoorchlorosubstitutedtribenzosilatranecompoundsR1Si(OPhR2)3N(R1R2=CNorCl)havemuchbiggerdipolemomentsoranisotropyofpolarizabilityandmorelikespherethanthecorrespondingalkylsubstitutedcompounds.Cyanoorchlorosubstitutedtribenzosilatraneswouldbebettercandidatesforsphere-likemeso-gens.
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简介:Anovelgel-likeprocesshasbeendevelopedforsynthesizingLiaNi0.8Co0.2O2powders,usingcitricacidasachelatingagent.Thisprocessimprovesthehomogeneityofconstituentcationandenhancestheirreactivityintheobtainedprecursor.Theresultsofelectrochemicaltestdemonstratedthatthesematerialsexhibitedexcellentelectrochemicalproperties.Itsinitialcapacityreached181.6mAh/gandreversibleefficiencyatthefirstcycleisabout88.6%.
简介:Anovelflower-likehydratedmagnesiumcarbonatehydroxide,Mg_5(CO_3)_4(OH)_2·4H_2O,withmicro-structurecomposedofindividualthinnano-sheetswassynthesizedusingafacilesolutionroutewithouttheuseoftemplateororganicsurfactant.Reactiontimehasanimportanteffectonthefinalmorphologyoftheproduct.Themicro-structureandmorphologyofMg_5(CO_3)_4(OH)_2·4H_2OwerecharacterizedbymeansofX-raydiffractometry(XRD),field-emissionscanningelectronmicroscopy(FE-SEM).Brunauer-Emmett-Teller(BET)surfaceareasofthesampleswerealsomeasured.Theprobableformationmechanismofflower-likemicro-structurewasdiscussed.ItwasfoundthatMg_5(CO_3)_4(OH)_2·4H_2Owithflower-likemicro-structurewasanovelandefficientcatalystforthesynthesisofdiphenylcarbonate(DPC)bytransesterificationofdimethylcarbonate(DMC)withphenol.