简介：Theradialvibrationcharacteristicofanannularultrasonicconcentratorwithmultislitsisstudied.Basedontheelectro-mechanicalanalogyandbyintroducinganarearatiocoefficient,theradialvibrationalequivalentcircuitandthefrequencyequationoftheconcentratorarederived.Theradialdisplacementamplitudemagnificationfactorofitisobtained.Bynumericalcalculating,therelationshipbetweentheradialdisplacementamplitudemagnificationfactor,theresonancefrequencyoftheconcentratoratthefirstandsecondresonanceanditsradiusratioareinvestigated.Also,therelationshipbetweentheradialdisplacementamplitudemagnificationfactor,theresonancefrequencyoftheconcentratorandthelength,theangleandthenumberofthesiltsareanalyzed.Itisillustratedthatamaximumofdisplacementamplitudemagnificationfactoroftheconcentratorappearswiththeincreaseoftheradiusratio,andtheamplitudemagnificationfactorincreaseasthelength,theangleandthenumberofthesiltsincrease,whiletheradialresonancefrequencyoftheconcentratordecreasesasthelength,theangleandthenumberofthesiltsincrease.ThetheoreticalresonancefrequenciesareingoodagreementwiththatoftheFEMsimulationsandmeasurement.

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简介：把陈和Hau的理论基于D.P，一个理论方法被介绍分析嘘类型表面的分散特征与一个变化原则和coupling-of-modes在周期的金属性的栅栏结构上宣传的声学的波浪(锯)方程。没有使用复杂格林的功能，方法的精明的结果Hashimoto的理论与那些同意很好。在另一方面，Hashimoto的方法为在ST-90上计算short-circuited栅栏的分散关系是无助的

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简介：Byusingthedynamicphotoelasticmethodandourtechniqueoffabricatinganinternalcrackinsolid,thescatteredwavesofincidentgrazinglongitudinalultrasonicwavepulsebyaribbon-typecrackareob-servedandanalyzed.Inparticular,thedistributionoftheintensityofthescatteredheadwaveismeasuredquantitatively.Theexperimentalresultsfairlyagreewiththetheoreticalonesgiveninref.[1].

简介：Scatteringofanincidentgrazinglongitudinalultrasonicwavepulsebyatraction-freeribbon-typecrackinsolidistheoreticallyanalyzed.Anexactseriessolutionofthescatteredfieldisobtainedbyiteration.Eachtermoftheseriescorrespondsroughlytooneoftherescatteringprocessesbytherespectivecracktips.Thefirsttwoterms,whichcombinetoformthesecondorderapproximatesolution,aredis-cussedindetail.This2nd-ordersolutionincludesscatteredcylindricallongitudinalwaves,cylindricalshearwaves,headwavesandsurfacewavesonthecracksurfaces,anditgivesgooddescriptionoftheearly-timewavefield.

简介：Regardforthefuzzinessandtherandomnessinsomeacousticfields,amethodforthenumericalanalysisofthe2DacousticfieldwithFuzzy-Randomparameterswasproposedbasedontheequivalentconversionofinformationentropy.Intheproposedmethod,afuzzyrandomacousticfieldwastreatedasapurefuzzyacousticfieldorapurerandomacousticfieldbytransformingallthevariablesintofuzzyvariablesorrandomvariables.Perturbationfiniteelementmethodsforanalyzingthetwo-dimensionalacousticfuzzyandrandomfieldarededuced.Thesoundpressureresponseofa2Dacoustictubeandthe2Dacousticcavityofacarwithfuzzy-randomparameterswereanalyzedbytheproposedmethodandtheMonteCarlomethod,theresultsshowthattheproposedmethodcanbewellappliedtothenumericalanalysisofthe2Dacousticfieldwithfuzzy-randomparameters,andhasgoodprospectofengineeringapplication.

简介：Foraccuracyandrapidityofaudioeventdetectioninthemass-dataaudioprocessingtasks,agenericmethodofrapidlyrecognizingaudioeventbasedon2D-HaaracousticsuperfeaturevectorandAdaBoostisproposed.Firstly,itcombinescertainnumberofcontinuousaudioframestobean'acousticfeatureimage',secondly,usesAdaBoost.MHorfastRandomAdaBoostfeatureselectionalgorithmtoselecthighrepresentative2D-Haarpatterncombinationstoconstructsuperfeaturevectors;thirdly,analyzesthecommonalityanddifferencesbetweensubcategories,thenextractscommonfeaturesandreducesdifferentfeaturestoobtainagenericaudioeventtemplate,whichcansupporttheaccurateidentificationofmultiplesub-classesanddetectandlocatethespecificaudioeventfromtheaudiostreamaccurately.Experimentalresultsshowthattheuseof2D-Haaracousticfeaturesupervectorcanmakerecognitionaccuracy5%higherthanonesthatMFCC,PLP,LPCCandothertraditionalacousticfeaturesyielded,andcanmakethetrainingprocessing7-20timesfasterandtherecognitionprocessing5-10timesfaster,itcanevenachieveanaverageprecisionof93.38%,anaveragerecallof95.03%undertheoptimalparameterconfigurationfoundbygridmethod.Aboveall,itcanprovideanaccurateandfastmass-dataprocessingmethodforaudioeventdetection.

简介：Anewapproachtodeterminealltheelectro-elasticconstantsofthepiezoelectriccrystalsinclass4mmhasbeenputforward.Asanexample,alltheconstantsofLithiumTetraborate（Li2B4O7）crystalhavebeenmeasuredbymeansoftheapproach.Theoutstandingadvantageoftheapproachisthatiton-lyneedstoemployinmeasurementthreecrystalplatesdifferentlyoriented.