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简介：Inthispaper,theenergyformulasofActiveSoundAbsorption(ASA)inspacesoundfieldhavebeenderivedfromthebasicsoundwaveequation,andASAincludingtherelevantconditionsofmultipolesecon-dary-source,suchasmonopole,dipoleandtripole,etc.,hasbeendis-cussed.Onthebasisofthediscussion,ithaspointedoutthatdipolesec-ondary-configuration(DAA)isthesimplestattenuator.TheresultsoftheexperimentsdoneinanechoicchamberhaveshownthatDAAhaseffectiveperformanceswhichjustprovidethefundationandfeasibilityofpracticaluse.

简介：Inthenormal-modetheoryofMorse,itgivesaseriesofnormalmodesasthesolutionofforcedvibrationinaroom.Butactuallythereisalwaysthedirectradiationbesidesthenormalmodeswhichrepresentthereverbrantsoundfieldonly.Thereasonisthatthenormalmodeswereassumedonlyinthesource,andnaturallynormalmodesonlyareobtainedinthesolution.Atheoryofdoublesourceisproposed,thatthesoundsourceisboththesourceofthedirectradiationasifinfreespacebeforetheboundarysurfaceswerereachedbythedirectradiation,andafterthefirstreflectionfromtheboundarysurfaces,thesourceofthereflectedwavelets,randomlydistributedbothinspaceanintimeontheboundarysurfacesthatbuildupthenormalmodesafterfurtherreflections.Thewaveequationisformedaccordingly,andthesolutionofthewaveequation,thesoundfieldinaroom,containsexplicitlyboththedirectradiationandthereverberantsoundformedofnormalmodes.Theapproximatemeansquaresoundpressureisfoundtobethedircetsounddeterminedbythesoundpowerofthesource,andreverberantsounddeterminedbythesoundpowerreducedbyafactorofπ/2,differentslightlyfromtheresultobtainedfromenergyconsideration,ifthesourceispuretone.Thereisessentiallynodifferenceforasourceofbandnoise.

简介：笔直的公路．将我们的目光引向苏格兰第一大城市——格拉斯哥。快速奔驰的车辆与乡间幽静的景色形成的对比给人留下了深刻的印象。而走在市区当中．则让人感受到这个城市里的轻松活泼的气氛。

简介：Itisconsiderednecessarythatanadditionaltermrepresentingthedirectsoundbeintroducedintotheclassicalnormalmodesolutionofsoundfieldinenclosures,toaccordwithpracticeandtomaketheformu-lamoreuseful.

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简介：Thispaperstudiestheinteractionofshockandgradientwave(soundwave)ofsolutionstothesystemofinviscidisentropicgasdynamicsasamodelforthecorrespondingproblemsfornonlinearhyperbolicsystems.Theproblemcanbereducedtoaboundaryvalueprobleminawedgeddormain,ByusingthemethodofconstructingasymptoticsolutionsandNewton'siterationprocessitisprovedthatifaweakshockhitsagradientwave,thenthegrandientwavewillsplitintotwogradientwaves,whiletheshockcontinusespropagating.Inthispapertheauthorreducestheproblemtoastandardformandconstructsasymptoticsolutionoftheproblem.Theexistenceofthegenuinesolutionwillhegiveninthefollowingpaper.

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简介：Numericalanalysisofthree-dimensionalsoundpropagationinsoft-softorsoft-hardcircularductswithcircumferentialandaxialmodesofsoundsourcesattheinlethasbeencarriedout.Inthispaper,thenumericalmethodandthesamplesareofferedandtheeffectsofcircumferentialandaxialmodesonnumericalresultsarediscussedindetail.

简介：这是一个性别的角色界限不再确定的年代,我们周围充斥着太多暧昧的声音。有个男人,正蘸着泥泞和风霜唱着歌,他是刘可。刘可是有胡子的男人。幼时学过二胡、少年当过司机、参军当过文艺兵、唱过一晚上挣10块钱的歌厅……我们无法从这个现在沉默安静的人身上读出当年的动荡和颠簸,但只要看他的眼神,你就知道,那是只有经历过世事变迁的人才会有的清澈和笃定。说到刘可的创作,我们必须提到一个人。他是刘可1998年到广州之后认识的朋友,正是从

简介：Thedeterminationofthesoundpowerofasourceissimpleinareverberationchamber,butusuallylowervalvesareobtainedatlowfrequenciesthanthefree-spacevalue.Itisshownthatthesoundpowerdeterminedinareverberationchamberdependsnotonlyonitsfree-spacepower,butalsoonthepositionsofthesourceandthereveiver,aswellasthewaythemeasurementsaremadeandaveraged.Exactandstatisticalformulasarederivedtoaccountforthesefactors.Theresultsexplainthediscrepancyandagreewellwithearlierexperiments.Basedonthetheory,parcticabletechniquesofsoundpowerdetermina-tionarepropesedandcorrectpowerformulaspresented.

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