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简介:以便讨论修改La的铅锆酸盐titanate锡酸盐antiferroelectric陶艺PbLaZr的非线性的机电的性质,Sn,TiO3PLZST,近似线性化的电致伸缩的方程古典线性压电的方程从秒顺序被导出的一模一样的形式概括压电的方程称为。解决非线性的antiferroelectric阶段转变陶艺变换器的电声的transduction问题的一条分析途径被介绍。PLZST的非线性的性质能基于为分析变换器的电声的transduction问题的近似线性化的电致伸缩的方程与维持的偏爱是线性地相等的。创新antiferroelectric陶艺有回声频率1.1kHz的低频率班IVflextensional变换器基于途径被开发它作为活跃元素利用PLZST。湖认证显示为变换器的PLZST的使用一会儿在它的PZT-4对应物上在在SL的TVR和9dB增加产出3dB增加,并且途径是有效的。
简介:Soundisoneoftheinformationcarriersoftenusedinanimalcommunication.Soundproducedbyani-malsisusefulnotonlyinintraspecificcommunication,butalsoinalarmoraggression.Threebasicproblemsinhearingshouldberesolvedi.e.frequencyselectivity,patternrecognitionandsounddirection.Withintracellularrecordingandsinglecellstainingtechniques,frequencyselectivityofprimaryauditoryneuronsinthebushcrickethasbeenstudied.Eachneuronhasitscharacteristicbestfrequency(BF)andtuningcurveinresponsetosound.Thecentralprojectionsoftheiraxonsintheprothoracicganglionareunilateral,non-transsegmentalandofsomecorrespondingrelationtotheirBFs.Neuralmechanismsforfrequencyanalysisinspecies-specificsongrecognitionofthebushcricketarediscussed.
简介:有步骤形状的三不同的墙节在建立由在三种情况中的步骤的高度作为相等被拿的墙modification.The在低频率声音地上调查效果的有限元素分析模型被使用、随机、优化。优化的值被在健全的地里与最小的变化的一个客观函数使用优化进程获得。有原来、修改的墙的房间的频率回答从60Hz在一个范围被计算到120Hz。结果证明有优化的墙节的房间有最扁平的频率反应。当这个房间的比率被改变,一样的事情是真的。变化上的最大的改进到达了4.5dB。另外,有半圆和三角的墙节被学习。围节的房间优化了半径,高度也比修理了半径和heights.Therefore的那些给了更好的表演,使用优化的墙节改善是可能的低频率声音地。
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简介:宣传在的瑞利波浪的散特征一成层的媒介被一个时间频率分析方法分析,光滑的Pseudo-WignerVille分发(RSPWVD)的重新分配。理论模拟和实验为同类的一半空间和二分层的一半空间被实现。在试验性的结果获得的不同频率范围的组速度分散曲线都相应于在他们的表面排水量振幅的主导的模式,这被显示。多模式瑞利波浪的如此的modeidentification在inversing被要求中等参数。
简介:瞄准underdeterminedconvolutive混合模型,一个盲目讲话来源分离方法基于掩盖的非线性的时间频率被建议,在在在时间频率领域的独立讲话信号之中的近似W拆散orthogonality(W做)性质被利用的地方。在这个方法,从multimicrophones的观察混合信号被使正常化起初独立于在时间频率域的频率,然后,动态聚类算法被采用在每时间频率槽获得积极来源信息,经由从簇中心的偏转角度的一个非线性的函数为掩盖的时间频率被选择,最后,混合讲话信号的盲目分离能被反的STFT(短时间的Fourier转变)完成。这个方法不能仅仅解决可以在很经典的频率域窗帘分离技术被遇见的频率排列的问题,而且压制分离矩阵的空间方向散开。模拟结果证明建议分离方法比典型蓝色方法好,signal-noise-ratio获得(SNRG)平均增加1.58dB。
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:Time-frequencyanalysisiscombinedwitharrayprocessingtodevelopadirectionofarrival(DOA)estimationmethod.Thearraydatamodelisconstructedintime-frequencydomainbycrosstime-frequencydistributionbetweentheoutputofareferencesensorandthoseoftwosymmetricsub-arrays.Accordinglyasubspacemethodispresentedbasedontheaverageoftwosub-arrays'time-frequencydatavectormodelinsteadoftheconventionalarraymodel,toestimateDOAsofmultiplesignals.Becausethearraydataisprocessedbothinspatialdomainand2-Dtime-frequencydomain,theproposedmethodhasanabilitytoselectthesignalofinteresting,andissuitablefornon-stationarysignal.Additionally,themethodisrobusttonoiseandholdsanadvantageoflowcomputationalload.Simulationsareconductedtoverifytheefficiencyofthemethodandcomparisionismadewithothermethods.
简介:Considertheproblemsoffrequency-invariantbeampatternoptimizationandrobustnessinbroadbandbeamforming.Firstly,aglobaloptimizationalgorithm,whichisbasedonphasecompensationofthearraymanifolds,isusedtoconstructthefrequency-invariantbeampattern.Comparedwithsomemethodspresentedrecently,theproposedalgorithmisnotonlyavailabletogettheglobaloptimalsolution,butalsosimpleforphysicalrealization.Meanwhile,arobustadaptivebroadbandbeamformingalgorithmisalsoderivedbyreconstructingthecovariancematrix.Theessenceoftheproposedalgorithmistoestimatethespace-frequencyspectrumusingCaponestimatorfirstly,thenintegrateoveraregionseparatedfromthedesiredsignaldirectiontoreconstructtheinterference-plus-noisecovariancematrix,andfinallycaleulatetheadaptivebeamformerweightswiththereconstructedmatrix.Thedesignofbeamformerisformulatedasaconvexoptimizationproblemtobesolved.Simulationresultsshowthattheperformanceoftheproposedalgorithmisalmostalwaysclosetotheoptimalvalueacrossawiderangeofsignaltonoiseratios.
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简介:Forthemulti-frequencyacousticanalysis,aseriesexpansionmethodhasbeenintroducedtoreducethecomputationtimeofthefrequency-independentparts,buttheRungephenomenonwillarisewhenthismethodisemployedinhighfrequencyband.Therefore,thismethodisimprovedbyanalyzingtheapplicationconditionandproposingtheselectionprincipleoftheseriestruncationnumber.Theargumentintervalcanbeadjustedwiththewavenumberfactor.Therefore,theproblemofunstablenumerationandpoorprecisioncanbesolved,andtheapplicationscopeofthismethodisexpanded.Thenumericalexampleofacousticradiationshowsthattheimprovedmethodiscorrectforacousticanalysisinwiderfrequencybandwithlessseriestruncationnumberandcomputationamount.
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