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简介：Performanceenhancementisconsideredanessentialpartofsport.1However,intheworldofcompetitiveandhigh-performancesports,thereisincreasingevidenceofahighprevalenceofperformance-enhancingdrugabuse.2-4Theuseofdrugsthatis,bannedsubstances-hasbecomeaseriousproblemwithsignificantsocial,ethical,policy,andpersonalconsequences,5-7andconsequentlycompromisestheintegrityofsportsandsportsmanshipatalllevelsofcompetition,aswellasthehealthandwell-beingofindividualathletesandpublichealthingeneral.

简介：Internalwavesplayacrucialroleinoceanmixing,anddensityperturbationandenergyfluxareessentialquantitiestoinvestigatethegenerationandpropagationofinternalwaves.Thispaperpresentsamethodologyforcalculatingdensityperturbationandenergyfluxofinternalwavesonlyusingavelocityfieldthatisbasedonlinearizedequationsforinternalwaves.ThemethodwastestedbynumericalsimulationsofinternalwavesgeneratedbytidalflowingoveraGaussiantopographyinastratifiedfluid.Thedensityperturbationsandenergyfluxesdeterminedusingourmethodthatonlyusedvelocitydataagreedwithdensityperturbationsandenergyfluxesdeterminedbytheequationofstatebasedontemperaturedata.Themeanrelativeerror（MRE）androotmeansquareerror（RMSE）betweenthetwomethodswerelowerthan5%and10%respectively.Inaddition,anexperimentwasperformedtoexamourmethodusingthevelocityfieldmeasuredbyParticleImageVelocimetry（PIV）,andthesetupoftheexperimentisconsistentwiththenumericalmodel.TheresultsoftheexperimentscalculatedbythemethodsusingPIVdatawerealsogenerallyequaltothoseofthenumericalmodel.

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简介：Theprincipleand1:3internalresonanceofarectangularthinplateinatransversemagneticfieldisinvestigated.Basedonthemagneto-elasticvibrationequationandelectromagneticforceexpressionsofthethinplates,thenonlinearmagneto-elasticvibrationdifferentialequationsofrectangularplatesunderexternalexcitationinatransversemagneticfieldarederived.Forarectangularplatewithonesidefixedandthreeothersidessimplysupported,thetwo-degree-offreedomnonlinearDuffingvibrationdifferen-tialequationsareproposedbythemethodofGalerkin.Themethodofmultiplescalesisadoptedtosolvethemodelequationsandobtainfourfirst-orderordinarydifferentialequationsgoverningmodulationoftheamplitudesandphaseanglesinvolvedviathefirst-orderorthesecond-orderprimary-internalreso-nances.Withanumericalexample,theamplitudefrequencyresponsecurves,timehistoryresponses,phaseportraitsandPoincaremapsofthefirsttwoordervibrationmodesviaprinciple-internalresonancearerespectivelycaptured.Andtheeffectsofexternalexcitationamplitudes,magneticfieldintensitiesandthicknessesonthevibrationofsystemarediscussed.Theresultsshowthattheresponseisdominatedbythelowmodewhenprinciple-internalresonanceoccurs.Theinternalresonanceprovidesamechanismfortransferringenergyfromahighmodetoalowmode.

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简介：Weemployedametallicwiregratingloadedwithgrapheneandoperatingintotalinternalreflection(TIR)geometrytorealizedeepandbroadbandTHzmodulation.Thenon-resonantfieldenhancementeffectoftheevanescentwaveinTIRgeometryandinthesubwavelengthwiregratingwascombinedtodemonstratea-77%modulationdepth(MD)inthefrequencyrangeof0.2–1.4THz.ThisMD,achievedelectricallywithaSiO2∕Sigatedgraphenedevice,was4.5timeshigherthanthatofthedevicewithoutametalgratingintransmissiongeometry.Byoptimizingtheparametersofthemetallicwiregrating,therequiredsheetconductivityofgraphenefordeepmodulationwasloweredto0.87mS.ThisworkhaspotentialapplicationsinTHzcommunicationandreal-timeTHzimaging.

简介：Thevibrationresponseofafree-hangingflexibleriserinducedbyinternalgas-liquidslugflowwasstudiedexperimentallyinasmall-diametertubemodelbasedonFroudenumbercriterion.Theflowregimeinacurvedrisermodelandtheresponsedisplacementsoftheriserweresimultaneouslyrecordedbyhighspeedcameras.Thegassuperficialvelocityrangesfrom0.1m/sto0.6m/swhiletheliquidsuperficialvelocityfrom0.06m/sto0.3m/s.Severesluggingtype3,unstableoscillationflowandrelativelystableslugflowwereobservedintheconsideredflowrates.Severesluggingtype3characterizedbyprematuregaspenetrationoccursatrelativelylowflowrates.Boththecycletimeandsluglengthbecomeshorterasthegasflowrateincreases.Thepressureattheriserbaseundergoesalongerperiodandlargeramplitudeoffluctuationascomparedwiththeothertwoflowregimes.Additionally,severesluggingleadstothemostvigorousin-planevibration.However,theresponsesintheverticalandhorizontaldirectionsarenotsynchronized.Theverticalvibrationisdominatedbythesecondmodewhilethehorizontalvibrationisdominatedbythefirstmode.Similartothevortex-inducedvibration,threebranchesareidentifiedasinitialbranch,build-upbranchanddescendingbranchfortheresponseversusthemixturevelocityofgas-liquidflow.