简介:Inthispaper,abeam-platecoupledstructureisdiscussed.Thederivationofexactexpressionsforpowertransferandnumericalcomputa-tionarecarriedon.ItisfoundthattheSEAtechniquesmaybeappropri-ateforstrongcoupledstructuresandthatthegeneralSEAresultprovidesgoodagreementwiththeexactcalculationwhenmodaloverlapishigh.Thederivedformulaisappliedtopredictthecouplinglossfactorandvibrationalenergyofsubstructures.Theagreementbetweentheestimatedandmeasuredresultspresentsquitewellinmostcases.
简介:Ultrasoundsimulationforcarotidarteriesishelpfultotheperformanceassessmentsofvesselwalldetectionandsignalprocessingmethodsbyusingultrasoundtechniques.Anultrasoundsimulationmethodofcarotidarterywallwithathree-membranestructureisproposedinpresentstudy.Accordingtotheultrasoundspeckledistributionsvaryingwiththeshapesanddensitiesofscattererdistributions,aswellasthestatisticresultsoftheclinicalimages,theparametersofdistributions,densitiesandintensitiesofscatterersfordifferentkindsoftissuesinthecarotidarteryphantomsaredetermined.EachregionisacousticallycharacterizedusingFIELDIIsoftwaretoproducetheradiofrequencyechosignals,fromwhichultrasoundimagesarederived.Theresultsbasedon30simulationsshowthattheechodistributionsoftheintimae,mediae,adventitiasandbloodareconsistentwiththeclinicalones.Moreover,comparedwiththeresultsfromthecentralfrequencyof8MHz,themeanmeasurementsforthicknessesoftheintima,mediaandadventitiamembranes,aswellasthelumendiameterfromthesimulationimagesbasedon12MHzarethesameasthepresetones,andthemaximumrelativeerrorsarethe4.01%,1.25%,0.04%and0.15%,respectively.Thesimulationunderthisconditionismorerealistic.
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