简介:TheexistenceandorbitalinstabilityofstandingwavesforthegeneralizedthreedimensionalnonlocalnonlinearSchr¨odingerequationsisstudied.Bydefiningsomesuitablefunctionalsandaconstrainedvariationalproblem,wefirstestablishtheexistenceofstandingwaves,whichrelysontheinnerstructureoftheequationsunderconsiderationtoovercomethedrawbackthatnonlocaltermsviolatethespace-scaleinvariance.Wethenshowtheorbitalinstabilityofstandingwaves.Theargumentsdependupontheconservationlawsofthemassandoftheenergy.
简介:Theaimofthispaperistogiveasimpleproofoftherestrictiontheoremforthemaximaloperatorsonthed-dimensionalEuclideanspaceRd,whosetheoremwasprovedbyCarro-Rodriguezin2012.Moreover,weshallgivesomeremarksoftherestrictiontheoremforthelinearandthemultilinearoperatorsbyCarro-RodriguezandRodriguez,too.
简介:Inthispaper,wereportedamultiwavelengthpassivelyQ-switchedYb3+:GdAl3(BO3)4solid-statelaserwithtopologicalinsulatorBi2Te3asasaturableabsorber(SA)forthefirsttime,tothebestofourknowledge.Bi2Te3nanosheetswerepreparedbythefacilesolvothermalmethod.TheinfluenceofthreeBi2Te3densitiesonthelaseroperationwascompared.Themaximumaverageoutputpowerwasupto57mWwithapulseenergyof511.7nJ.Theshortestpulsewidthwasmeasuredtobe370nswith110kHzpulserepetitionrateand40mWaveragepower.Thelaseroperatedatthreewavelengthssimultaneouslyat1043.7,1045.3,and1046.2nm,ofwhichthefrequencydifferenceswerewithintheterahertzwaveband.OurworksuggeststhatsolvothermalsynthesizedBi2Te3isapromisingSAforsimultaneouslymultiwavelengthlaseroperation.
简介:Commerciallyavailablelatticescontainvariouskindsofmorphologicalimperfectionswhichresultingreatdegradationinlattices’mechanicalproperties,therefore,toobtainimperfectioninsensitivelatticestructureisobviouslyapracticalresearchsubject.Hierarchicalstructurematerialswerefoundtobeaclassofpromisinganti-defectmaterials.Thispaperbuildshierarchicallatticebyaddingsoftadhesiontolattice’scelledgesandnumericalresultsshowthatitsimperfectionsensitivitytomissingbarsisminorcomparedwiththeclassiclattice.Softadhesionwithappropriatepropertiesreinforcecelledge’sbendingstiffnessandthusreducethebendingdeformationinlatticecausedbymissingbarsdefect,whichisconfirmedbystatisticalanalysisofnormalizednodedisplacementsofimperfectlatticesunderhydrostaticcompressionandshearloads.
简介:Open-loopflowcontrolmethodwasusedtoaffectthedevelopmentofaturbulentwakebehindaD-shapedbluffbody.Loudspeakerswereembeddedinsidethebluffbodytoproducetwozero-net-massfluxjetsthrough2mm-widespan-wiseslotslocatedalongtheupperandloweredgesontherearwall.Thedragforcesfordifferentactuationamplitudes(C_μtheratiobetweenthemomentumoftheactuatingjetsandthemomentdeficitcausedbythebluffbody)andfrequencies(Sr_A)wereexamined.Theeffectsofthephasedifferenceinthetwojets(0andπ)werealsostudied.ItwasfoundthatwhenC_μwas0.1%,adragreductionupto5%wasachievedwhenthevelocitiesofthetwojetsvariedinphaseatafrequencyofSt_A=0.16.Whenthevelocitiesofthetwojetsvariedrroutofphase,significantdragincreasewasobserved.
简介:Generally,ROSareregardedashostdefensemoleculesthatarereleasedbyneutrophilstodestroyexogenouspathogenssuchasbacteriaandtoactassecondarymessengersinsignaltransduction.However,increasedproductionofROSisalsoinvolvedininducingpathophysiologicalchangessuchasapoptosis,cellcycledisruption,andnecrosis.Forthisreason,inductionofROS-mediateddamageincancercellsbypharmacologicalagentsthateitherpromoteROSgenerationordisablethecellularantioxidantsystemisconsideredapotentialtherapeuticstrategyforpreferentiallykillingcancercells[1].
简介:Pt/WO3/CnanocompositeswithparallelWO3nanorodsweresynthesizedandappliedasthecathodecatalystforprotonexchangemembranefuelcells(PEMFCs).Electrochemicalresultsandsinglecelltestsshowthatanenhancedactivityfortheoxygenreductionreaction(ORR)isobtainedforthePt/WO3/CcatalystcomparedwithPt/C.ThehighercatalyticactivitymightbeascribedtotheimprovedPtdispersionwithsmallerparticlesizes.ThePt/WO3/Ccatalystalsoexhibitsagoodelectrochemicalstabilityunderpotentialcycling.Thus,thePt/WO3/CcatalystcanbeusedasapotentialPEMFCcathodecatalyst.
简介:Theshapeofnanostructurehasimportanteffectsontheirproperties,thereforeinthisstudy,wehavepreparedandcharacterizedthreedifferentmorphologiesofWO3nanostructuresi.e.nanorod,nanosphereandnanoplateforsurveyingshapeeffectontheirphotocatalyticpropertiestowarddegradationofRhodamineB(RhB)dye.ObtainedresultsshowthatnanoplateWO3incomparisonwithothershasthebestphotocatalyticactivity.AccordingtoSEM,andphotocatalyticdegradationresults,thereasonforthisbehavioristhesharpedgesandcornersofWO3nanoplates.Becauseoftheirlowcoordinationnumber,atomslocatedintheedgesandcornersoftheWO3nanoplateshavemoreactivity,adsorbmoreRhBandthereforegivemorephotocatalyticactivitytotheWO3nanoplates.UsingofdifferentscavengersshowedthathydroxylradicalsaremainlyresponsibleforphotocatalyticactivityofWO3nanoplatesandnanospheresbutforWO3nanorods,superoxideradicalsarethemainphotocatalyticdegradationagents.
简介:Wakestructuresandvortexinducedvibration(VIV)ofaspring-supportedwide-D-sectioncylinderwereexperimentallyinvestigatedusinganX-wire,anovelphase-lockedparticleimagevelocimetry(PIV),andanaccelerationsensoratalowspeedwindtunnel.Comparedwiththefixedcase,the2P(twopair)vortexmodeasdefinedbyGovardhanandWilliamson(2000)ratherthanS(singlevortex)modeexistsinthewake.Thevelocitydeficitbehindthecylinderismuchlargerthanthatoffixedcase.Themeandragcoefficientincreasesfrom1.42forthefixedcaseto1.64forthevibratingcase.TheReynoldsstresspresentsevendistributionandsmallwithincreaseddistanceofX/D=-2toX/D=-10.Thepowerspectradensitybasedonacceleratorandhotwiredatapresentsahighlightidentical.Itshowsthatafterastronginteractionthecylindervibrationandthevortexsheddingcometoastablestate.Thevortexsheddingistotallylockedonandcontrolledbythecylindervibration.
简介:Grapheneanditsderivativeshaveattractedtremendousresearchinterestbecauseoftheiruniquecompositionandphysicochemicalproperties[1??3].However,thepotentialbiologicaltoxicityofGQDshasbecomeahealthriskbecauseoftheirinherentchemicalcompositionandnanoscaleproperties[4].Zebrafish(Daniorerio)isoneofthemostpromisinginvivomodelsystemsfortoxicitystudies[5].
简介:Foraccuracyandrapidityofaudioeventdetectioninthemass-dataaudioprocessingtasks,agenericmethodofrapidlyrecognizingaudioeventbasedon2D-HaaracousticsuperfeaturevectorandAdaBoostisproposed.Firstly,itcombinescertainnumberofcontinuousaudioframestobean'acousticfeatureimage',secondly,usesAdaBoost.MHorfastRandomAdaBoostfeatureselectionalgorithmtoselecthighrepresentative2D-Haarpatterncombinationstoconstructsuperfeaturevectors;thirdly,analyzesthecommonalityanddifferencesbetweensubcategories,thenextractscommonfeaturesandreducesdifferentfeaturestoobtainagenericaudioeventtemplate,whichcansupporttheaccurateidentificationofmultiplesub-classesanddetectandlocatethespecificaudioeventfromtheaudiostreamaccurately.Experimentalresultsshowthattheuseof2D-Haaracousticfeaturesupervectorcanmakerecognitionaccuracy5%higherthanonesthatMFCC,PLP,LPCCandothertraditionalacousticfeaturesyielded,andcanmakethetrainingprocessing7-20timesfasterandtherecognitionprocessing5-10timesfaster,itcanevenachieveanaverageprecisionof93.38%,anaveragerecallof95.03%undertheoptimalparameterconfigurationfoundbygridmethod.Aboveall,itcanprovideanaccurateandfastmass-dataprocessingmethodforaudioeventdetection.