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简介：Acousticimpulsesproducedthroughthemechanismofthelaser-inducedbreakdowninwaterhavebeeninvestigatedintherangefrom0℃toroomtemperature.Differentlyfromtheacousticimpulsesproducedviathermalexpansion,thepolarityandtheamplitudeofacousticimpulseproducedvialiquidbreakdownmechanismdonotchangewithwatertemper-ature.Thisindirectlyprovesthattheproductionofacousticimpulseisduetotheexpansionofthecavityitselfwhichincludesplasma.Asemiempiricaldescriptionofthisphenomenonisgiveninthispaper.

简介：TheresearchaimistoinvestigatethathowpitchanddurationaffecttheperceptionoftheneutraltoneinstandardChineseandthatwhichoneofthetwofactorsismoreimportant.Apsycho-acousticexperimentwasconducted,inwhichthelisteningstimuliconsistedof15groupsofdisyllabicwords,andthepitchesanddurationsofthetwosyllablesineachofthewordswereartificiallycontrolled.Thirty-threestandardChinesenativespeakersparticipatedinaforced-choicetasktojudgeifthesecondsyllablesofthewordstheyheardcarriedtheneutraltoneorthenormaltones.Theresultsoftheexperimentindicatedthat,(1)theeffectsofbothpitchanddurationontheperceptionoftheneutraltonearesignificant;(2)theeffectofpitchislargerthanthatofduration;(3)boththeF0valuesofthehighpointinthepitchcontourandthepitchcontourpatternhaveinfluenceontheperception.Theresultsoftheexperimentwerecorrespondenttosomeextenttothoseofthepreviousacousticanalysesontheneutraltone.Thediversitybetweentheresultsofthepresentedperceptualstudyandthoseoftheacousticalstudiesimpliesthattheacousticfeaturesoftheneutraltonethatexistinnaturalspeechwhiledonotaffecttheperceptionmaybephonologicallyredundant.

简介：浅水里的matchedfield处理的时间的关联(MFP)上的线性、独居的内部波浪的效果数字地与不同频率为声学的来源被调查，深度基于从experiment.It的海洋学的数据被显示出MFP的时间的关联作为独居的内部波浪的振幅减少或线性内部波浪increases.For的平均精力密度有更低的频率的声学的来源或下面定位了thermocline，tempor

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简介：Byinvestigatingtheeffectsondeepoceanambientnoiseoftyphoon'KAI-TAK'whichpassedthenorthareaoftheSouthChinaSea,itisshownthatthewindspeed,therainfallintensityandthelongwaveswellcausedbytyphoonaffecttheoceanambientnoisesignificantly.Thecorrelationbetweentheoceanambientnoiseandthewindspeedduringthetyphoonismuchbetterthanthatinthenon-typhoonperiodinthesameBeaufortscale.Analysisofthecorrelationbetweenthe415hoceanambientnoisemeasureddataandwindspeedshowsthat,whenthefrequencyisgreaterthan300Hz,thecorrelationcoefficientbetweentheoceanambientnoiseandthewindspeedisgreaterthan0.5,achievingamoderatecorrelation;whenthefrequencyisgreaterthan630Hz,thecorrelationcoefficientisbetween0.8and0.9,achievingahighdegreeofcorrelation.Thecorrelationbetweentheoceanambientnoiseandthewindspeedisbetterthanthatbetweentheoceanambientnoiseandthesignificantwaveheightwhenthefrequencyisgreaterthan300Hz.Thecorrelationbetweentheoceanambientnoiseandthewindspeedininfrasonicbandfrom10Hzto20HzispoorintheSouthChinaSea,becausetheshippingisbusyinthisseaareaandtheoceanambientnoiseiscontaminatedbytheshipnoiseevenduringthetyphoon.

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简介：Inthispaperthepropertiesofspace-timecorrelationfunctionofthenoisefieldofmovingsourceinlayeredstatisticinhomogeneousmediumarestudiedandtheeffectsofrandomfluctuatingboundaryarecon-sideredaswell.Ithasbeenshown,theoreticallyandexperimentally,multi-pathpropergatingeffectscausethedispersionofthecorrelationfunctionandfluctuationsofthemediumrefractionindexandtheboundarycausethefluctuationofit.Theeffectofthemovementofthenoisesourceontheoutputofreal-timecorrelatorisequivalenttoalow-passfilteraddedthedriftofspace-timecorrelationfunction.Thesepropertiesofthecorrelationfunctioncausegravedegradationofthesignalprocessinggainofnoiserangingsonarsystem.Thefluctuatingandthedistortionofconrrelationfunctionmadeitdifficulttorealizethenoiseranging.Sointhispaper,amethodofspacecorrelationrangingbyalineararrayoffourpointswithshortseparationandlongspanandatechnigueofdual-correlationsignalp