简介：ThegoalofthisstudyistoanalyzethestatisticsofthebackscattersignalfrombovinecancellousboneusingaNakagamimodelandtoevaluatethefeasibilityofNakagami-modelparametersforcancellousbonecharacterization.Ultrasonicbackscattermeasurementswereperformedon24bovinecancellousbonespecimensinvitroandthebackscattersignalswerecompensatedforthefrequency-dependentattenuationpriortotheenvelopedetection.ThestatisticsofthebackscatterenvelopeweremodeledusingtheNakagamidistribution.Ourresultsrevealthatthebackscatterenvelopemainlyfollowedpre-Rayleighdistributions,andthedeviationsofthebackscatterenvelopefromRayleighdistributiondecreasedwithincreasingbonedensity.TheNakagamishapeparameter(i.e.,m)wassignificantlycorrelatedwithbonedensities(R=0.78–0.81,p<0.001)andtrabecularmicrostructures(|R|=0.46–0.78,p<0.05).Thescaleparameter(i.e.,?)andsignal-to-noiseratio(SNR)alsoyieldedsignificantcorrelationswithbonedensityandstructuralfeatures.Multiplelinearregressionsshowedthatbonevolumefraction(BV/TV)wasthemainpredictoroftheNakagamiparameters,andmicrostructureproducedsignificantlyindependentcontributiontothepredictionofNakagamidistributionparameters,explaininganadditional10.2%ofthevarianceatmost.TheinvitrostudyshowedthatstatisticalparametersderivedwithNakagamimodelmightbeusefulforcancellousbonecharacterization,andstatisticalanalysishaspotentialforultrasonicbackscatterboneevaluation.

简介：Insulatorsonhigh-voltageUansmissionlinesarealmosttheonlyman-madestructuresontheEarth'ssurfaceintendedforlong-termoperationunderstrongelectricfields.AftersamplesofnaturalcontaminantparticleswerecollectedfrominsulatorsurfacesinChina,itwasfoundthattheparticlediameterdistribution(PDD)wasmainlyconcentratedinthe5-50μmrange.Toanalyzethestatisticalcharacteristicsoftheseparticles,thisworkstudiesthephysicalprocessesofparticlecollisionandadhesionusingthetheoriesofhydrodynamicsandcollisiondynamics.Thephysicalmodelconsiderscouplingofthefluidfieldandtheelectricfield,introducesanadhesioncriterion,andestablishesaparticleandsurfacecollisionmodel.Theeffectsofrelativehumidity,windspeed,aerodynamicshape,electricfieldtype,andelectricfieldstrengthonparticleadhesionwereanalyzed.Theresultsshowthattherelativehumidityandwindspeedhaveverysignificanteffectsandtheinfluencesoftheelectricfieldtypeandtheelectricfieldstrengthareobvious,buttheinfluenceoftheaerodynamicshapeisrelativelyweak.Thesimulationresultssupportthestatisticalcharacteristicsdeterminedinthiswork.Thephysicalmodelestablishedhereprovidesreferencevaluesforstudyoftheadhesioncharacteristicsofparticlesonsurfacesunderelectricfields.