简介:ThestatisticalpropertiesofthemodeconvertedSVwavespecklesinthebackscatteringspacewerestudiedasultrasonicPwaveswereincidentonastronglyscatteringinterface.BasedontheFrensel-Huygenstheoryandthecorrelationprinciple,theRayleighdistributionoftheSVwavespeckleamplitudeandtheformulaforcalculatingtheaveragelateralsizeoftheSVwavespeckleswereobtained.Besides,theprobabilitydensityfunctionofthenormalizedintensityoftheSVwavespecklesreceivedbyatransversewaveprobewithanapertureofsomesizewasdeduced.Theprobabilitydensityfunctionwasrelatedtotheaveragenumberofthespecklesreceivedbytheprobe.TwotransversewaveprobeswithaperturesindifferentsizewereemployedtomeasurethesoundintensityoftheSVwavespecklesintheexperiment.Aftertheexperimentaldataofthespeckleintensitywereanalyzedstatistically,itwasshownthattheexperimentalresultswereingoodagreementwiththetheoreticalones.Thus,thepresentedtheoreticalconclusionswereprovedtobecorrect.
简介:Thisstudyperformsthequantitativeanalysisandcomparisontoacousticsignalcharact,eristicsofLargcyellowcroaker(Pseudosciaenacrocea)attwodifferentages.Thesoundswercrecordedfromthefishesinanet-cage.Twoexponentialoscillationfunctionsarebuilttofittheacousticsignalofthefishes.Thesignalcharacteristicoftheoscillationfrequencyandattcnuationcoefficientwasdescribedquantitatively.Simulationcurvesofthefunctioncouldfitwellacousticsignals.Boththeaverageoscillationfrequencyandattenuationcoefficientofthefittedsignalsfromthe13-15-month-oldfishesarclowerthanthosefromthe7-8-month-oldfishes.Theresultssuggestthattheoscillationfrequencyandattenuationcoefficientoftheacollsi.icsignalfunctionmayberelevanttothephysicalproccssofsoundproductionandagecharacteristicsofLargeyellowcroaker.Thisstudymaybevaluablefortheacousticapplicationtotheartificialcultureofthespecies.