简介：Itiswellknownthatsurfaceroughnesshasaveryimportanteffectonsuperhydrophobicity.TheWenzelandCassie-Baxtermodels,whichcorrespondtothehomogeneousandheterogeneouswettingrespectively,arecurrentlyprimaryinstructionsfordesigningsuperhydrophobicsurfaces.However,theparticulardropshapethatadropexhibitsmightdependonhowitisformed.Awaterdropcanoccupymultipleequilibriumstates,whichrelatetodifferentlocalminimalenergy.Insomecases,bothequilibriumstatescanevenco-existonasamesubstrate.Thustheapparentcontactanglesmayvaryandhavedifferentvalues.WediscusshowtheWenzelandCassie-Baxterequationsdeterminethehomogeneousandheterogeneouswettingtheoretically.Contactangleanalysisonhierarchicalsurfacestructureandcontactanglehysteresishasbeenputspecificattention.Inparticular,westudytheenergybarrieroftransitionfromCassie-BaxterstatetoWenzelstate,basedonexistingachievementbypreviousresearchers,todeterminethepossibilityofthetransitionandhowitcanbeinterpreted.Ithasbeendemonstratedthatsurfaceroughnessandgeometrywillinfluencetheenergyrequiredforadroptogetintoequilibrium,nomatteritishomogeneousorheterogeneouswetting.

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简介：Whencharacterizingflowsinminiaturizedchannels,thedeterminationofthedynamiccontactangleisimportant.Bymeasuringthedynamiccontactangle,theflowpropertiesoftheflowingliquidandtheeffectofmaterialpropertiesontheflowcanbecharacterized.Amachinevisionbasedsystemtomeasurethecontactangleoffrontorrearmenisciofamovingliquidplugisdescribedinthisarticle.Inthisresearch,transparentflowchannelsfabricatedonthermoplasticpolymerandsealedwithanadhesivetapeareused.Thetransparencyofthechannelsenablesimagebasedmonitoringandmeasurementofflowvariables,includingthedynamiccontactangle.Itisshownthatthedynamicanglecanbemeasuredfromaliquidflowinachannelusingtheimagebasedmeasurementsystem.AnimageprocessingalgorithmhasbeendevelopedinaMATLAB?environment.Im-agesaretakenusingaCCDcameraandthechannelsareilluminatedusingacustommaderinglight.Twofittingmethods,acircleandtwoparabolas,areexperimentedandtheresultsarecomparedinthemeasurementofthedynamiccontactangles.

简介：Ceramicsaregoodalternativetometalasbearingcouplematerialsbecauseoftheirbetterwearresistance.AFiniteElement(FE)studywasperformedtoinvestigatethecontactmechanicsandstressdistributionofCeramic-on-Ceramic(COC)hipresurfacingprostheses.Itwasfocusedinparticularonaparametricstudytoexaminetheeffectsofradialclearance,loading,aluminacoatingontheimplants,bonequality,andfixationofcup-boneinterface.Itwasfoundthatareductionintheradialclearancehadthemostsignificanteffectonthepredictedcontactpressuredistributionamongalloftheparametersconsideredinthisstudy.Itwasdeterminedthattherewasasignificantinfluenceofnon-metallicmaterials,suchastheboneunderneaththebearingcomponents,onthepredictedcontactmechanics.Stressshieldingwithinthebonetissuewasfoundtobeamajorconcernwhenregardingtheuseofceramicasanalternativetometallicresurfacingprostheses.Therefore,usingaluminaimplantswithametalbackingwasfoundtobethebestdesignforceramicresurfacingprosthesesinthisstudy.Theloading,bonequality,andacetabularcupfixationconditionswerefoundtohaveonlyminoreffectsonthepredictedcontactpressuredistributionalongthebearingsurfaces.

简介：Thethree-dimensional(3D)structurepredictionofproteinsisanimportanttaskinbioinformatics.Findingenergyfunctionsthatcanbetterrepresentresidue-residueandresidue-solventinteractionsisacrucialwaytoimprovethepredictionaccuracy.Thewidelyusedcontactenergyfunctionsmostlyonlyconsiderthecontactfrequencybetweendifferenttypesofresidues;however,wefindthatthecontactfrequencyalsorelatestotheresiduehydrophobicenvironment.Accordingly,wepresentanimprovedcontactenergyfunctiontointegratethetwofactors,whichcanreflecttheinfluenceofhydrophobicinteractiononthestabilizationofprotein3Dstructuremoreeffectively.Furthermore,afoldrecognition(threading)approachbasedonthisenergyfunctionisdeveloped.Thetestingresultsobtainedwith20randomlyselectedproteinsdemonstratethat,comparedwithcommoncontactenergyfunctions,theproposedenergyfunctioncanimprovetheaccuracyofthefoldtemplatepredictionfrom20%to50%,andcanalsoimprovetheaccuracyofthesequence-templatealignmentfrom35%to65%.