简介：金属橡胶材料的健全吸收表演理论上并且试验性地被学习。声学的阻抗率和健全吸收系数基于金属橡胶材料的声学的参数被导出。结构常数，压缩的可能性模量和结构的参数的关系试验性地被调查。结果证明有一样的吝啬的孔直径的金属橡胶的标本有一样的结构常数。为一样的结构的参数，金属橡胶材料的压缩的可能性模量在某些频率范围是近似不变的。计算声学的参数在对试验性的结果的好同意，表明理论模型的有效性。

简介：Soundsourcerecognitionisapartofenvironmentalsoundrecognition,whichisoneofthemostimportantresearchareasinpatternrecognition.Impactsoundscarrymuchphysicalinformationassociatedwiththesoundsources,whichmakesimpactsoundbasedsoundsourcerecognitionanimportantapproachtoimproverecognitionperformance.Inthisstudy,theimpactsoundcontinuumsynthesizedwithaball-platecollisionmodelisusedformaterialrecognitionoftheimpactedplates.Thebasisfunctionlearningmethodandtime-frequencyrepresentationmethods,includingtheshorttimeFouriertransformandthewaveletpackettransform,areappliedintoclassificationandtherecognitionresultsarecompared.TheresultshowsthatthefeaturesobtainedbyusingthebasisfunctionlearningperformbetterformaterialclassificationoftheimpactedplatesthanthatbyusingtheshorttimeFouriertransformandthewaveletpackettransform.Thisdemonstratesthehighefficiencyandsuperiorityofthismethodinmaterialrecognitionofsoundsources.

简介：AkindofcircularringhighfrequencywidebandunderwateracoustictransducerisdevelopedbyusingtheLowQvalueandbroadbandcharacteristicsofthepiezoelectricitycompositematerial,andthedualmodecouplingisusedtobroadenthebandwidthofthetransducerbydoubleringstackingalongtheaxialdirection.Throughtheoreticalanalysisandsimulationcalculation,thegeometricdimensionsofthesensitivecomponentsaredetermined.Thepiezoelectriccompositeringsareprocessedandthenthestacksensitiveelementcanbemadebystackingtwopiezoelectriccompositeringswiththesameouterdiameteranddifferentthicknessinaxialdirectionbycuttingpiezoelectricceramicsfillingtheflexiblepolymer-coatingelectrode.Finally,thetransducercanbemadebypouringwaterproofsound-permeablelayer.Theperformancesoftransducerhavealsobeentestedinthewaterandthetestresultsshowthattheresonantfrequencyis410kHz,themaximumtransmitvoltageresponseis150dB,the-3dBbandwidthcanreaches60kHz,thehorizontaldirectivity(-5dB)is360°,andtheverticaldirectivity(-3dB)is20°.Itisalsoshownthatthebandwidthofthetransducercanbeenlargedremarkablybyusingthemethodofstackingtwodifferentthicknesspiezoelectriccompositeringsalongtheaxialdirection,andthehorizontalomnidirectionalemissionofacousticwavecanberealized

简介：