简介：Basedonelementarygrouptheory,theblockpivotmethodsforsolv-ingtwo-dimensionalelasticfrictionalcontactproblemsarepresentedinthispaper.Itisprovedthatthealgorithmsconvergewithinafinitenumberofstepswhenthefrictioncoefficientis'relativesmall'.Unlikemostmathematicalprogrammingmeth-odsforcontactproblems,theblockpivotmethodspermitmultipleexchangesofbasicandnonbasicvariables.

简介：Anewpreparationmethodhasbeendevelopedforthermallystableporouspolyimidemicrospheres.Porouspolyimidemicrosphereswerepreparedusingtriblockcopolymersthatconsistedofathermallystablepolyimidederivedfrompyromelliticdianhydride/4,4’-oxydianilineasthecontinuousphaseandathermallylabilepolyetherasthedispersedphase.Spheresofcopolymersweregeneratedinanonaqueousemulsionandthengraduallyheatedtocompletetheimidizationtoformamicrophase-separatedstructure.Subsequently,thermaltreatmentataslightlyreducedpressureremovedthelabileblocksandproducedpores.Undersuitabledecompositionconditions,theporesizeoftheporouspolyimidewasintherangeof200-400nm.

简介：Inthispaperwereviewourworkonself-assemblyofthesystem,poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide)(PEO-PPO-PEO)blockcopolymers,whichisakindofmacromolecularcomplexfluids.Thecontrolofself-assemblycouldbeobtainedbyaddinginorganicsaltsoraliphaticalcohols.Byself-assemblyofamphiphilicblockcopolymers,amicroemulsionphaseisformed,whichcouldbeappliedinmicelleextraction,suchashollow-fibermembranemicelleextraction,magneticmicelleextractionandimmobilizedmicelleextraction.

简介：Theplasticdeformationsoftemperedmartensitesteelrepresentativevolumeelementswithdifferentmartensiteblockstructureshavebeeninvestigatedbyusinganonlocalcrystalplasticitymodelwhichconsidersisotropicandkinematichardeningproducedbyplasticstraingradients.Itwasfoundthatpronouncedstraingradientsoccurinthegrainboundaryregionevenunderhomogeneousloading.Theisotropichardeningofstraingradientsstronglyinfluencestheglobalstress–straindiagramwhilethekinematichardeningofstraingradientsinfluencesthelocaldeformationbehaviour.Itisfoundthattheadditionalstraingradienthardeningisnotonlydependentontheblockwidthbutalsoonthemisorientationsorthedeformationincompatibilitiesinadjacentblocks.