简介：WederivedrevisedeffectivediffusionenergybarriersfollowingtheBoltzmanndistributionassumptionforimpurityatomsinabulkmaterialundertheimpactofvariouskindsofpointdefectstorevealtheinsightsofmigrationmechanisms.Theeffectivediffusionenergybarriersofcopperimpuritiesinbulkzirconiumwerecalculatedthroughthefirstprinciplemethodunderthepresentedhypothesis.Ourresults(?E||=1.27eV,?E⊥=1.31eV)agreedwellwiththeexperimentalresults(?E||=1.54eV,?E⊥=1.60eV),whichvalidatedbulkdiffusionasthemajormechanismforcopperdiffusioninzirconium.Theeffectivediffusionenergybarrierscouldbeusedforestimatingwhetherthedefectswillacceleratethediffusionorslowthemdownbyactingastrapsoftheimpurityatoms.Ontheotherhand,thefirstprincipleresultsoftheimpuritydiffusionviadefectscouldbefurtherusedasinputsoflargerscalecomputationalsimulations,suchasMC(MonteCarlo)orPhaseFieldcalculations.

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简介：Afundamentaltheoryfortheanalysisofresidualweldingstressesanddeformationbasedontheinherentstraindistributionalongtheweldedjointisintroduced.Distributionofinherentstrainsandlongitudinalresidualstressesinmediumthicknessplateweldmentiscalculatedandanalyzed.Anewmethodofcalculatinginherentstrainsandlongitudinalresidualstressesisproposed.

简介：Anewtestmethodwasintroducedtomeasurefiberdistributioninsteelfiberreinforcedmortarbyusingimageanalysistechnique.Throughspecimenpreparation,imageacquisition,fiberextraction,andmeasurementofrelatedfiberparameters,quantitativeanalysisoffiberdistributioncouldbeobtainedbytwoparameters,namelydispersioncoefficientandorientationfactor.Effectofboundaries,sizeandsteelfibercontentonfiberdistributionwasdiscussed.Resultsshowedthat,steelfiberdistributionwasaffectedbyboundaryeffect,whichwouldbeweakenedwiththeincreaseofspecimensize.Ifthelengthandwidthremainedconstant,thespecimenheighthadasignificanteffectonorientationfactoroffiber,whileitsinfluenceondispersioncoefficientwasnotsoobvious.Withtheincreaseofsteelfibercontent,dispersioncoefficientdecreasedslightly,andorientationfactordeviatedfrom0.5.

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