简介:Moststudiesofseismicnoisecross-correlation(NCC)havefocusedonregional/continentalscaleimagingusingempiricalsurface-waveGreen’sfunctionsextractedfromprimary(0.05–0.08Hz)andsecondary(0.1–0.16Hz)microseisms.Inthiswork,wepresenttheNCCresultsathigherfrequencies([0.5Hz)from6monthsseismicnoiserecordedbyalocalarray(*4kmaperture)deployedalongtheCalicofaultintheMojaveDesert,California.BothfastandslowpropagatingwavesareobservedfromtheNCCrecord-sections.WecomparetheNCCsfromsensorpairsthatshareacommonsensorwiththerecordsofaboreholeshotlocatedveryclosetothiscommonsensor.Theresultshowsagoodmatchoftheslowsurface-wavearrivals,indicatingthattheNCCmethodisabletorecoverunbiasedsurface-waveGreen’sfunctionsatlocalscales.Thestrongbody-waveNCCcomponentiscausedbythePwavesgeneratedoffshoreCalifornia.AlongaSW–NEprofileacrossthefault,weobserveapparentP-wavearrivalsandtheirreflections,whichcanbeexplainedbyalow-velocityzone(LVZ)alongtheCalicofault.WecalculatetheLVZwidthtobe*2.3km,andtheP-wavevelocityreductionwithintheLVZtobe*35%.TheseestimatesareconsistentwithotherevidenceforarelativelywideLVZalongtheCalicofault.
简介:Anewnoisereductionmethodbasedonensembleempiricalmodedecomposition(EEMD)isproposedtoimprovethedetectioneffectforfluorescencespectra.Polycyclicaromatichydrocarbons(PAHs)pollutants,asakindofimportantcurrentenvironmentalpollutionsource,arehighlyoncogenic.Usingthefluorescencespectroscopymethod,thePAHspollutantscanbedetected.However,instrumentwillproducenoiseintheexperiment.Weakfluorescentsignalscanbeaffectedbynoise,soweproposeawaytodenoiseandimprovethedetectioneffect.Firstly,weusefluorescencespectrometertodetectPAHstoobtainfluorescencespectra.Subsequently,noisesarereducedbyEEMDalgorithm.Finally,theexperimentresultsshowtheproposedmethodisfeasible.
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:Four-wavemixing,aswellasitsinducedintensitynoise,isharmfultowavelengthdivisionmultiplexingsystems.Theefficiencyandtherelativeintensitynoiseoffour-wavemixingarenumericallysimulatedforthetwo-waveandthethree-wavefibertransmissions.Itisfoundthattheefficiencydecreaseswiththeincreaseofboththefrequencyspacingandthefiberlength,whichcanbeexplainedusingthequasi-phase-matchingcondition.Furthermore,therelativeintensitynoisedecreaseswiththeincreaseoffrequencyspacing,whileitincreaseswiththeincreaseoffiberlength,whichisduetotheconsiderablepowerlossofthepumplight.Thisinvestigationpresentsagoodreferenceforthepracticalapplicationofwavelengthdivisionmultiplexingsystems.
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简介: 古怪阴离的南方C城在这个初春的乌语花香中奇怪招展,宛如爱丽丝梦境里出现的那些奇装异束的扑克牌士兵,燃着闪闪发光鳞片似的破碎诗歌章节.……
简介:Thispaperpresentsanewapproachforattenuatingcoherentnoisein3Dseismicdata.Anadaptivebeamformingwithgeneralizedsidelobecanceller(GSC)designmethodologyisutilizedhereasageneralformoflinearlyconstrainedadaptivebeamformingstructure.Itconsistsofafixedbeamformer,andasignal-blockingmatrixinfrontofanunconstrainedadaptivebeamformer.Considerationfofthecomplexityofthegeometryfor3Dseismicsurvey,the3DbeamformingwithGSCtechniqueisdevelopedwithtwokeypoints:(1)sortingalongazimuthsectionstosimplifytherelationshipbetweentraveltimeandoffsetfrom3Dto2D,and(2)dynamicbinningschemetoavoidthepossiblepoorfoldinginsomeazimuthsections.Bothsimulationresultandrealdataexampleshowthatthenewlydeveloped3DbeamformingwithGSCyieldsmorecredibleresultsatarelativelowcost,sufficientstabilityandgoodresolution.
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简介:TheYellowstonevolcanoisoneofthelargestactivevolcanoesintheworld,anditspotentialhazardsdemanddetailedseismologicalandgeodeticstudies.Previousstudieswithtraveltimetomographyandreceiverfunctionshaverevealedalow-velocitylayerinthecrustbeneaththeYellowstonevolcano,suggestingthepresenceofamagmachamberatdepth.Weuseambientseismicnoisefromregionalseismicstationstoretrieveshort-periodsurfacewavesandthenstudytheshallowshearvelocitystructureoftheYellowstoneregionbysurfacewavedispersionanalysis.WefirstobtainedacrustalmodeloftheareaoutsideoftheYellowstonevolcanoandthenconstructedanabsoluteshearwavevelocitystructureincombinationwithreceiverfunctionresultsforthecrustbeneaththeYellowstonevolcano.Thevelocitymodelshowsalow-velocitylayerwithshearvelocityataround1.3km/s,suggestingthatalarge-scalemagmachamberexistsatshallowlevelswithinthecrustoftheYellowstonevolcanicregion.
简介:Inthispaper,weinvestigatecoherenceresonance(CR)andnoise-inducedsynchronizationinHindmarsh-Rose(HR)neuralnetworkwiththreedifferenttypesoftopologies:regular,random,andsmall-world.ItisfoundthattheadditivenoisecaninduceCRinHRneuralnetworkwithdifferenttopologiesanditscoherenceisoptimizedbyapropernoiselevel.Itisalsofoundthatascouplingstrengthincreasestheplateauinthemeasureofcoherencecurvebecomesbroadenedandtheeffectsofnetworktopologyismorepronouncedsimultaneously.Moreover,wefindthatincreasingtheprobabilitypofthenetworktopologyleadstoanenhancementofnoise-inducedsynchronizationinHRneuronsnetwork.
简介:WeproposeaschemeformitigatingRayleighbackscatteringnoiseanddemodulatingdifferentialphaseshiftkeying(DPSK)signalsinwavelength-division-multiplexedpassiveopticalnetworks(WDM-PONs)withinjection-lockedFabry-Perotlaserdiodes(FP-LDs).SignaldemodulationandwavelengthconversionaresimultaneouslyrealizedonthebasisofthefrequencydeviationandredshiftoflongitudemodesintheFP-LDs.Experimentalresultsdemonstratethatthedemodulationandwavelengthconversionof2.5-Gb/sDPSKsignalsareachieved.Apowerpenaltyofabout1.6dBatabiterrorrateof109ismeasuredaftertransmissionover25-kmsinglemodefiber.
简介:Toinvestigatetheglutamate-likeimmunoreactivity(Glu-IR)changesininnerhaircells(IHCs)ofguineapigscochlearafternoiseexposure.Guineapigsweredistributedinto6groupsincludingcontrolgroup(gl),andgroupsofimmediately(g2),8hours(g3),1day(g4),3days(g5)and7days(g6)afternoiseexposure.Theexperimentalgroupswereexposedto120dBLp1/3octave4kHznarrowbandnoisefor4hourstoruintheorganofCorti.ThefirstturnoftheorganofCortiwasdissectedtomakeultrathinsectionsandunderwentimmunoelectronstudy.ThedensityofgoldparticlesofGlu-IRinIHCswasmeasured.ResultsshowedthatGlu-IRinIHCsafternoiseexposurechangeddynamically.ThedensityofgoldparticleinIHCsofg2significantlyincreased(p<0.001)comparedwithglanddecreaseding3(p<0.001),whereastherewerenosignificantdifferenceinthegroupsofg4,g5andg6(p>0.05).TheresultssuggestthattheremaybeglutamateautoreceptorsinthemembraneofIHCsandtheglutamatereleasedfrompre-synapsemayactontheseautoreceptorsinapostitivefeedbackmanner,whichinduced[Ca^2+]increasedinIHCsimmediatelyafternoiseexposure.GlutamatesynthetasesystemwasactivatedbyCa^2+andmoreglutamicacidwasproduced.Inthegroupof8hoursafternoiseexposure,glutamicaciddecreasedinIHCsbecauseofitsover-releasingintosynapses.Glu-IR'srecoverytonormallevelindicatedthattheglutamateglutaminecyclemayexistinguineapigcochlea.
简介:在现在的纸,最大的Lyapunov代表为一种合作尺寸被调查在上的二个分叉系统一三维中央对由围住的噪音的参量的刺激歧管、使\O遭到。由使用一个不安方法,一个一个维的阶段散开过程的不变的措施的表情为三个案例被获得,在哪个矩阵B的不同形式,那在噪音刺激术语被包括,被假定然后作为结果,为一个维的阶段散开过程的所有三种单个边界被分析。经由Monte-Carlo模拟,我们发现不变的措施的分析表情遇见数字的很好。并且而且,P分叉行为为一个维的阶段散开过程被调查。为为一个维的阶段散开过程的单个边界的三个案例,最后,最大的Lyapunov代表的分析表达式为随机的分叉系统被介绍。
简介:Theanalyticalexpressionofbiterrorprobabilityinabalanceddifferentialphase-shiftkeying(DPSK)opticalreceiverconsideringnonlinearphasenoiseandEDFAASEnoiseisgiven,whichisveryusefultoestimatetheperformanceofDPSKbalancedandunbalancedreceiverinopticalcommunicationsystem.Throughanalysis,ifonlynonlinearphasenoiseisconsidered,boththebalanceandunbalancedreceivershavethesameperformances.ButifaddingtheASEnoiseofEDFA,thebalancedreceiverisbetter.
简介:Objective:TodemonstratetheperformancebenefitoftheAutomaticSceneClassifier(SCAN)algorithmavailableintheNucleus6(CP900series)soundprocessoroverthedefaultprocessingalgorithmsofthepreviousgenerationNucleus5(CP810)andFreedomHybridTMsoundprocessors.Methods:Eighty-twocochlearimplantrecipients(40Nucleus5processorusersand42FreedomHybridprocessorusers)listenedtoandrepeatedAzBiosentencesinnoisewiththeircurrentprocessorandwiththeNucleus6processor.Results:TheSCANalgorithmwhenenabledyieldedstatisticallysignificantnon-inferiorandsuperiorperformancewhencomparedtotheNucleus5andFreedomHybridsoundprocessorsprogrammedwithASCtADRO.Conclusion:TheresultsofthesestudiesdemonstratethesuperiorperformanceandclinicalutilityoftheSCANalgorithmintheNucleus6processorovertheNucleus5andFreedomHybridprocessors.