简介:0.General;1.PhysicalAcoustics;2.UnderwaterSound;3.MechanicalVibrationandShock;4.NoiseandFourgroupsofguineapigswereexposedtobudsound(3h,1kHz.125dBSPL).Onegroupinhaledairascontrol(C-group),andtheothergroupsingaled2ATAhyperbaricoxygen(HBO)for30minuteseachtime.Thesethreegroupswerecalled,respectively,preventiongroup(P-group)inhalingHBOoncebeforeexposure,treatmentgroup(T-group)inhalingHBOdailyfor14daysafterexposure,andprevention-treatmentgroup(PT-group)inhalingHBOoncebeforeexposureandonceadayfor14daysaf-terexposure.Afterexposure.thethresholdofthecorticalauditorypotentialevokedbyclickroseinallani-mals.HearinglossofC-groupwastheseverest,upto70dB,whilethoseofP-groupandPT-groupwhere53dBand51dB,respectively(p<0.01,comparedwiththatofC-group).HearinglossofT-groupwas68.5dB.Smilarphenomenawerefoundinthemeasurementbytone-burst.Theaboveaspectslasted21daysuntiltheseanimalswerekilled.Theaveragetraumalengthof
简介:0.General;1.PhysicalAcoustics;2.UnderwaterSound;3.MechanicalVibrationandShock;4.NoiseandNoiseControl;5.Ultrasonics;6.SpeechAsousticsandSpeechCommunication;7.Physio-logicalAcoustics;8.ArchitecturalAsoustics;9.Electroacoustics;10.AcousticalMeasurementandInstrumentation;11.AmosphericAcoustics;12.Geoacoustics;13.Bioacoustics;14.MusicalAcous-tics;15.SignalProcessing
简介:0.General;1.Physicalacoustics;2.Underwatersound;3.Mechanicalvibrationandshock;4.Noiseandnoisecontrol;5.Ultrasonics;6.Speechacousticsandspeechcommunication;7.Physio-logicalacoustics;8.Architecturalacoustics;9.Electroacoustics;10.Acousticalmeasurementandinstrumentation;11.Atmosphericacoustics;12.Geoacoustics;13.Bioacoustics;14.Musicalacoustics;15.Signalprocessing.
简介:ARevisedEditionofthenow-classical1971texteditedbyL.Beranek,NoiseandVibrationControl,hasbeenpublishedbytheInstituteofNoiseControlEngineering.NoiseandVibrationControlisofgreatvaluetodesignandsafetyengineers,consultants,scientists,architects,governmentresearchers,publicofficialsandothersconcernedwiththecontrolofnoiseemittedbymachineryandwithcontrolofenvironmentalnoiseinbuildings,intheworkplace,nearairportsandhighways,andinthecommunity.This
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简介:TostudythespatialdifferenceofoceanambientnoiseinoffshoreChinaandrevealitsgenerationmechanism,thedifferencebetweenthenoiselevel(NL)oftwostationsiscomparedbasedonlong-termobservationdatacollectedinthesameseason.Consideringtheinfluenceofunderwateracousticchannelsandthecharacteristicsofnoisesources,thetransmissionlosslevel(TL)fromtheportshipnoisesourcestothemeasuringstationisanalyzedanditshowsastrongcorrelationbetweenthetransmissionlossdifference(TLD)andnoiseleveldifference(NLD)atthebandof50-500Hz.Atthesametime,theanalysisofshipnoisesourcelevel(SL)presentsadifferenceabout20dBbetweenthetwoports,correspondingtothevariationoftheshipdensitybeforeandduringthefishingmoratorium.Theresultsprovethattheambientnoiseiscloselyrelatedtoshipnoisesourcesatthisfrequencyband,andthenoisedifferencebetweenthetwostationsresultsfromthetransmissionlossandtheshipnoisesources.
简介:ProfessorBeranektalkedaboutthesoundqualitiesofconcerthall.The58famousconcerthallsintheworldweregradedaccordingtothesubjectivecomparisonfromtheprofessionalmusiciansandmusiclovers.Sixmeasurableobjectiveparameterswereproposed.Therankingaccordingtotheseparameterswerepresented.
简介:Byinvestigatingtheeffectsondeepoceanambientnoiseoftyphoon'KAI-TAK'whichpassedthenorthareaoftheSouthChinaSea,itisshownthatthewindspeed,therainfallintensityandthelongwaveswellcausedbytyphoonaffecttheoceanambientnoisesignificantly.Thecorrelationbetweentheoceanambientnoiseandthewindspeedduringthetyphoonismuchbetterthanthatinthenon-typhoonperiodinthesameBeaufortscale.Analysisofthecorrelationbetweenthe415hoceanambientnoisemeasureddataandwindspeedshowsthat,whenthefrequencyisgreaterthan300Hz,thecorrelationcoefficientbetweentheoceanambientnoiseandthewindspeedisgreaterthan0.5,achievingamoderatecorrelation;whenthefrequencyisgreaterthan630Hz,thecorrelationcoefficientisbetween0.8and0.9,achievingahighdegreeofcorrelation.Thecorrelationbetweentheoceanambientnoiseandthewindspeedisbetterthanthatbetweentheoceanambientnoiseandthesignificantwaveheightwhenthefrequencyisgreaterthan300Hz.Thecorrelationbetweentheoceanambientnoiseandthewindspeedininfrasonicbandfrom10Hzto20HzispoorintheSouthChinaSea,becausetheshippingisbusyinthisseaareaandtheoceanambientnoiseiscontaminatedbytheshipnoiseevenduringthetyphoon.
简介:O.General;1.Physicalacoustics;2.Underwatersound;3.Mechanicalvibrationandshock;4.Noiseandnoisecontrol;5.Ultrasonics;6.Speechacousticsandspeechcommunication;7.Physiologicalacoustics;8.Ar-chitecturalacoustics;9.Electroacoustics;10.Acousticalmeasurementandinstrumentation;11.Atmosphericacoustics;12.Geoacoustics;13.Bioaoustics;14.Musicalacoustical;15.Signalprocessing.
简介:AmethodtoidentifycomplexYoung’smodulusofviscoelasticmaterialsusingforcedlongitudinalvibrationofslenderrodsisproposed.Themethoddiffersfromthebeamone.Experimentaltestswerecarriedoutatroomtemperaturewithdifferentlengthsin108mm,100mm,90mm,83.5mm,80mm.74.5mm,70mmforthepolycarbonatebars,andthecurvesofratiosA2/A1betweentwoendsofaviscoelasticbarversusfrequenciesareobtained,furthermore,thecorresponding3dBbandwidthandthestorageandlossmoduluscanbecalculated.SufficientnumberofobtainedcomplexYoung’smodulusatdifferentfrequencyallowsustocalculateotheronesusingtheleastsquaremethod.Ifthestepofthetestedfrequencyis5Hz,themaximumerrorofresultscanbelessthan6%.Bycomparisonwiththemeasurementmethodswhichthepreviousliteraturementioned,thisnewmethodsimplifiesthecalculation,andthephysicalmeaningappearsapparentlyandclearly.
简介:BasedonthenoisesurveyinChina,theformula(H′=H+N-HN/120)ofISO/DIS1999.2("Acous-tics-DeterminationofOccupationalnoiseexposureandestimationofnoise-inducedhearingimpairment,1985)wasappliedtothecalculationofthehearingthresholdlevelassociatedwithageandnoise(HTLAN)ofthenoise-impairedpeople.AccordingtotheGaussciandistribution,whenthenoise-exposurelevelLEX8hwas85,90,95,100dBandthehearingthresholdfrequencyisfrom0.5kto6kHz,theHTLANofnoise-exposedpeoplewithdifferentdurationofexposureanditsrelationvaluestothehearingthresholdfrequencyassociatedwithage(HTLA)wereobtained.TheISO/DIS1999.2hasbeenprovedtobeapplicableinChina.
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简介:基于液体动力学,热转移和声学的结果,一个计算液体动力学(CFD)方法被利用在一根Rijke管子内学习声学的特征和自我刺激的跳动机制。为了避免解决有限振幅的站的荒谬的边界条件,在Rijkethermo声学的系统飘动,在流动领域里当模特儿的模拟,它联合了有它的外层空间的管子内部,被执行代替传统的方法处于良好的竟技状态内部流动地数字调查。为在包括在热来源,摆动压力和摆动速度附近的空气的不稳定的热上的关系的精力方程的热来源的一个假设被介绍。为了反映Rijke的本质,尖叫,自我刺激的摆动上的模拟借助于它压力,速度和温度的自己的跳动被进行。这个方法能使集中过程稳定并且有效地避免分叉。自我刺激的Rijke管子的物理现象被分析。而且,Rijke管子的自我刺激的摆动上的机制是这个方法上的explained.Based,关于有不同尺寸和嘴的不同形状的Rijke管子的声学的特征的比较研究被执行。模拟结果令人满意地同意了试验性的数据。结果证明这数字模拟能被用来为Rijke管子的设计申请学习嘴的健全压力。