简介：Theapplicabilityandlimitationofseveralquadraticstrengththeorieswereinvestigatedwithrespectto2D-C/SiCand2.5D-C/SiCcomposites.Akindofdamage-basedfailurecriterion,referredtoasD-criterion,isproposedfornonlinearceramiccomposites.Meanwhile,thenewlydevelopedcriterionispreliminarilyvalidatedundertension-shearcombinedloadings.ThepredictionshowsthatthefailureenvelopegivenbyD-criterionislowerthanthatfromTsai–HillandHoffmancriteria.Thisrevealsthatthedamage-basedcriterionisreasonableforevaluationofdamage-dominatedfailurestrength.

简介：Alkalimetalhydroxideandhydridecompositesystemscontainbothprotic(HbondedwithO)andhydridichydrogen.Theinteractionofthesetwotypesofhydridesproduceshydrogen.Theenthalpyofdehydrogenationincreasedwiththeincreaseofatomicnumberofalkalimetals,i.e.,-23kJ/molH2forLiOH-LiH,55.34kJ/molH2forNaOH-NaHand222kJ/molH2forKOH-KH.Thesethermodynamiccalculationresultswereconsistentwithourexperimentalresults.H2wasreleasedfromLiOH-LiHsystemduringballmilling.ThedehydrogenationtemperatureofNaOH-NaHsystemwasabout150℃;whereasKOHandKHdidnotinteractwitheachotherduringtheheatingprocess.Instead,KHdecomposedbyitself.Inthesethreesystems,NaOH-NaHwastheonlyreversiblehydrogenstoragesystem,theenthalpyofdehydrogenationwasabout55.65kJ/molH2,andthecorrespondingentropywasca.101.23J/(molH2K),sothetemperatureforreleasing1.0barH2wasashighas518℃,showingunfavorablethermodynamicproperties.TheactivationenergyforhydrogendesorptionofNaOH-NaHwasfoundtobe57.87kJ/mol,showinggoodkineticproperties.

简介：二维(2D)有multilayered质地的碳/碳(C/C)composites，特别与不同厚度高度粗糙(HT)pyrocarbon层，被等温的、等压的化学蒸汽渗入(CVI)准备技术。C/Ccomposites的机械性质上的矩阵微观结构的影响被极化的轻显微镜学调查，扫描电子显微镜学和三点的弯曲测试。结果证明有多层粗糙的pyrocarbon矩阵的样品与纯媒介粗糙的结构比那件拥有更高曲折的力量，它被归因于多重裂缝偏转并且在HT层以内的在不同粗糙的pyrocarbon层之间并且在亚层之间的界面的滑动。HTpyrocarbon层的厚度的增加改进样品的粘性并且在伪塑料行为显示破裂。

简介：Two-dimensional(2-D)BiVO4nanosheets-graphene(GR)compositeswithdifferentweightadditionratiosofGRhavebeenpreparedviaafacilewetchemistryprocess.X-raydiffraction(XRD),Ramanspectra,X-rayphotoelectronspectra(XPS),UV-visdiffusereflectancespectra(DRS),field-emissionscanningelectronmicroscopy(FE-SEM),transmissionelectronmicroscopy(TEM),nitrogenadsorption-desorption,transientphotocurrentresponseandphotoluminescence(PL)spectrawereemployedtodeterminethepropertiesofthesamples.ItisfoundthatBiVO4nanosheetscouldpavewellonthesurfaceofgraphenesheets.BiVO4nanosheets-GRcompositeswithaproperadditionamountofGRexhibitedhigherphotocatalyticactivitythanbareBiVO4nanosheetstowardliquid-phasedegradationofrhodamineB(RhB)andmethylorange(MO)undervisiblelightirradiation.TheenhancementofphotocatalyticactivitiesofBiVO4nanosheets-GRcompositescanbeattributedtotheeffectiveseparationofphotoexcitedelectron-holepairs.Thisworknotonlyprovidesasimplestrategyforfabricatingspecific2-Dsemiconductor-2-DGRcomposites,butalsoopensanewwindowofsuch2-Dsemiconductor-2-DGRcompositesasvisiblelightphotocatalyststowardanimprovedvisiblelightphotoactivityinpurifyingpollutedwaterresources.

简介：Semi-solidAl2Y/AZ91magnesiummatrixcompositesslurrywaspreparedbyultrasonicvibration,effectofultrasonicvibrationtemperatureandtimeonmicrostructureofsemi-solidslurrywasinvestigated.Theresultsshowedthatwiththeultrasonicvibrationtemperaturedecreasingthesolidvolumefractionofsemi-solidslurryincreased.Thebestultrasonicvibrationtemperaturewas600oC.Withtheincreaseofultrasonicvibrationtime,theaveragegraindiameterofprimaryа-Mgparticlesdecreasedfirstly,thenincreased,theaverageshapefactorincreasedgraduallyanddecreasedslightlyafter90s,andafewrosettedendriteswereobservedafter120s.Thebestsemi-solidslurrywithaveragegraindiameterof75μmandshapefactorof0.7weregainedafterthemeltwastreatedbyultrasonicvibrationforabout60satnearliquidustemperature(600oC).Atlast,themicrostructureevolutionmechanismofsemi-solidmagnesiummatrixcompositesslurrywasanalyzedbythetheoriesofthermodynamicsandkinetics.