简介：Thisstudyinvestigatestheeffectivenessofthenon-smoothsemi-activecontrolalgorithmonsuppressingthevibrationperformanceofabuildingstructuresubjectedtoseismicwaves.AccordingtotheLyapunovstabilitytheory,ithasbeneproventhatthenon-smoothsemi-activecontrolalgorithmcanachieveafinite-timestabilityofthevibrationrelativetotheisolationlayerofabuildingstructure.Throughnumericalsimulationoftwobuildingswithdifferentparameterssubjectedtotheinputofaseismicwave,thevibrationconditionsofpassivecontrol,LQRsemi-activecontrolandnon-smoothsemiactivecontrolarecomparedandanalyzed.Thesimulationresultsshowthatthenon-smoothsemi-activecontrolalgorithmhasabetterrobustnessandeffectivenessinrestrainingtheimpactofearthquakesonthestructure.

简介：Interestinthenonlinearpropertiesofmulti-modeopticalwaveguideshasseenarecentresurgenceonaccountofthelargedimensionalityaffordedbytheplatform.Thelargevolumeofmodesinthesewaveguidesprovidesanewspatialdegreeoffreedomforphasematchingnonlinearopticalprocesses.However,thisspatialdimensionisquantized,whichnarrowstheconversionbandwidthsofintermodalprocessesandconstrainsspectralandtemporaltailoringofthelight.Hereweshowthatbyengineeringtherelativegroupvelocitywithinthespatialdimension,wecantailorthephase-matchingbandwidthofintermodalparametricnonlinearities.Wedemonstrategroup-velocity-tailoredparametricnonlinearmixingbetweenhigher-ordermodesinamulti-modefiberwithgainbandwidthsthataremorethananorderofmagnitudelargerthanthatpreviouslythoughtpossibleforintermodalfour-wavemixing.Asevidenceofthetechnologicalutilityofthismethodology,weseedthisprocesstogeneratethefirsthigh-peak-powerwavelength-tunableall-fiberquasi-CWlaserintheTi:sapphirewavelengthregime.Moregenerally,withthecombinationofintermodalinteractions,whichdramaticallyexpandthephase-matchingdegreesoffreedomfornonlinearoptics,andintermodalgroup-velocityengineering,whichenablestailoringofthebandwidthofsuchinteractions,weshowcaseaplatformfornonlinearopticsthatcanbebroadbandwhilebeingwavelengthagnostic.

简介：Forthepurposeofsolvingoptimalcontrolproblemofawall-crawlingmobilerobotworkingonsphericalcontainers,weproposetheHamel'sformalismforPontryaginMaximumPrinciple,whichgivesageneralframeworkfortheoptimalcontrolofamechanicalsystemwithvelocityconstraints,especiallynonholonomicconstraints.Theeffectivenessoftheproposedframeworkisshownbythesimulationsfortheaboveproblem.

简介：AnartificialdisturbanceisintroducedintotheboundarylayeroveraflatplatetoinvestigatetheeffectonthetransitionprocessintheMach6.5windtunnelatPekingUniversity.Alinearstabilitytheory(LST)isutilizedtopredicttheevolutionoftheeigenmodes,andthefrequencyoftheartificialdisturbanceischosenaccordingtotheLSTresults.Theartificialdisturbanceisgeneratedbyglowingdischargeonthesurfaceoftheplateclosetotheleadingedge.TheRayleigh-scatteringvisualizationandparticleimagevelocimetry(PIV)measurementsareperformed.Bycomparingtheexperimentalresultswithartificialdisturbanceswiththoseunderthenaturalcondition(withoutartificialdisturbances),thepresentpapershowsthatthesecond-modeinstabilitywavesaresignificantlystimulatedbytheartificialdisturbances,andtheboundarylayertransitioniseffectivelytriggered.

简介：Two-monthcontinuouswaveformsof108broadbandseismicstationsinFujianProvinceanditsadjacentareasareusedtocomputenoisecross-correlationfunction(NCF).ThesignalqualityofNCFisimprovedviatheapplicationoftime-frequencyphaseweightedstacking.TheRayleighandLovewavesgroupvelocitiesbetween1s-20saremeasuredonthesymmetricalcomponentoftheNCFwiththemultiplefiltermethod.Morethan5,000Rayleighwavedispersioncurvesandabout4,000Lovewavedispersioncurvesareobtainedandusedtoinvertforgroupvelocitymaps.Thisdatasetprovidesabout50kmresolutionthatisdemonstratedwithcheckerboardtests.Consideringtheoffgreatcircleeffectininhomogeneousmedium,theraypathistracedbasedonthetraveltimefieldcomputedwithafinitedifferencemethod.Theinvertedgroupvelocitymapsshowgoodcorrelationwiththegeologicalfeaturesintheupperandmiddlecrust.TheFuzhoubasinandZhangzhoubasinshowedlowvelocityontheshortperiodgroupvelocitymaps.Onthelongperiodgroupvelocitymaps,thelowvelocityanomalyinthehighheatflowregionnearZhangzhouandclearvelocitycontrastacrosstheZhenghe-Dapufaults,whichsuggeststhattheZhenghe-Dapufaultmightbeadeepfault.

简介：Graphene,definedasasingleatomicplaneofgraphite,isasemimetalwithasmalloverlapbetweenthevalenceandconductionbands.Thestackingofgrapheneuptoseveralatomiclayerscanleadtodiversephysicalproperties,dependingonthestackingmethod.Bilayergrapheneisalsoasemimetal,adoptingtheAB-stacked(orBernal-stacked)structureortherareAA-stackedstructure.Trilayerorfew-layergraphene(FLG)canbesemimetalsorsemiconductors,dependingonwhethertheyadoptBernal(ABA)stackingorrhoinbohedral(ABC)stacking.

简介：Inthisresearch,thevibrationofelevatorropes,includingthemainropeandcompensationropeareinvestigatedsimultaneouslyinahigh-riseelevatorsystemunderearthquakeexcitation.Moreover,thepaperpresentsanewcontrolmethodtorestraintheswayofbothropes.Thisstudyconsidersvaryingropelengthsduringelevatoroperationwhichcauseothersystemparameterssuchasnaturalfrequency,anddampingratiotobetime-variantvariables.Thedynamicsoftheropesareanalyzedbysolvingthegoverningnon-stationary,nonlinearequationnumerically.Inordertomitigatethevibrationofropesinseveralmotionconditions,particularlyupwardsmovement,downwardmovement,stoppedatthelowestposition,andstoppedatthehighestposition,anactiveequipmentisinstalledatthecompensationsheave.Thestabilityofthesystemusingthecontrollerisanalyzedatfourstates:withoutdisturbanceandstaticcar,withoutdisturbanceandmobilecar,includingdisturbanceandstaticcar,andincludingdisturbanceandmobilecar.Theefficiencyofthecontrollerusedfordampeningthevibrationofelevatorropesisvalidatedbynumericalsimulationresults.

简介：AIM:Toidentifyriskfactorsassociatedwithpost-cataractsurgeryendophthalmitis(PCE)intype2diabeticpatients.METHODS:Ahospital-basedretrospectivecase-controlstudywasconductedon194type2diabeticpatientsundergoingcataractsurgeryinRajavithiHospitalfromJanuary2007toDecember2015.FifteenpatientswithPCEwereincludedasthecasegroupand179patientswithoutPCEwereincludedasthecontrolgroup.PotentialfactorsassociatedwithPCEamongbothgroupsincludingdemographics,pre-operativecharacteristics,surgicalsettingsandcomplications,werestatisticallyanalyzedusingChi-squaretestingandalogisticregressionmodel.RESULTS:Withinthecasegroup,53%werefemalesandthemedianagewas68y.Univariateanalysisofpre-operativecharacteristics,surgicalsettingsandcomplicationsrevealedthatrecentpre-operativefastingplasmaglucose,insulintherapy,presenceofdiabeticretinopathy,andseverenon-proliferativeorproliferativediabeticretinopathyweresignificantlyassociatedwithPCE.Inamultivariateanalysisadjustingforbloodglucoselevel,insulintreatmentwastheonlysignificantfactorassociatedwithanincreasedriskofPCE(OR3.9,95%CI1.0-15.0,P=0.04)comparedtopatientswithoutinsulintreatment.Themostcommoncausativeorganismsweregram-positivebacteria(89%).Staphylococcusspeciesrepresentedthemostcommongroup(67%).Medianbestcorrectedvisualacuityat1-monthand3-monthfollow-upwasequalat0.7logMAR(20/100).CONCLUSION:Theauthorsidentifyinsulintreatmentastheonlyriskfactorassociatedwithendophthalmitisaftercataractsurgeryintype2diabeticpatients.Furtherstudieswithserumlevelsofpre-operativeglycatedhemoglobin(HbA1c)andpost-operativefastingplasmaglucoselevelareessentialtotrulydemonstratetheroleofperi-operativeglycemicmarkersasariskfactorforPCE.

简介：Inthispaper,aerodynamicactuationcharacteristicsofradio-frequency(RF)dischargeplasmaarestudiedandamethodisproposedforshockwavecontrolbasedonRFdischarge.Underthestaticcondition,aRFdiffuseglowdischargecanbeobserved;underthesupersonicinflow,theplasmaisblowndownstreambutremainscontinuousandstable.Time-resolvedschlierenisusedforflowfieldvisualization.ItisfoundthatRFdischargenotonlyleadstocontinuousenergydepositionontheelectrodesurfacebutalsoinducesacompressionwave.Underthesupersonicinflowcondition,aweakobliqueshockwaveisinducedbydischarge.Experimentalresultsoftheshockwavecontrolindicatethattheappliedactuationcandispersethebottomstructureoftheramp-inducedobliqueshockwave,whichisalsoobservedintheextractedshockwavestructureafterimageprocessing.Moreimportantly,thiscontroleffectcanbemaintainedsteadilyduetothecontinuoushigh-frequency(MHz)discharge.Finally,correlationsforschlierenimagesandnumericalsimulationsareemployedtofurtherexploretheflowcontrolmechanism.Itisobservedthatthevortexintheboundarylayerincreasesaftertheapplicationofactuation,meaningthattheboundarylayerinthedownstreamoftheactuationpositionisthickened.Thisisequivalenttocoveringalayeroflow-densitysmoothwallaroundthecompressioncornerandontherampsurface,therebyweakeningthecompressibilityatthecompressioncorner.OurresultsdemonstratetheabilityofRFplasmaaerodynamicactuationtocontrolthesupersonicairflow.

简介：【摘要】： 按我国电力行业标准， 300MW 及以上机组的火电厂运行人员必须经过仿真机培训。可见，仿真机培训在火电机组安全稳定运行的重要性。如何提高仿真机的培训效果， 本文笔者 历经多次教学和大赛集训教练工作 , 总结出一些实际经验 。

简介：Tuningthecoloroutputofrare-earthiondopedluminescentnanomaterialshasimportantscientificsignificanceforfurtherextendingapplicationsincolordisplays,lasersources,optoelectronicdevices,andbiolabeling.Inpreviousstudies,pre-designedphasemodulationofthefemtosecondlaserfieldhasbeenproventobeeffectiveintuningtheluminescenceofdopedrare-earthions.Owingtothecomplexlight–matterinteractionintheactualexperiment,thedynamicrangeandoptimalefficiencyforcolortuningcannotbedeterminedwiththepre-designedphasemodulation.Thisarticlesharesthedevelopmentofanadaptivefemtosecondpulseshapingmethodbasedonageneticalgorithm,anditsusetomanipulatethegreenandredluminescencetuninginanEr3+-dopedglassceramicunder800-nmfemtosecondlaserfieldexcitationforthefirsttime.ExperimentalresultsshowthattheintensityratioofthegreenandredUCluminescenceofthedopedEr3+ionscanbeeitherincreasedordecreasedconvenientlybythephase-shapedfemtosecondlaserfieldwithanoptimalfeedbackcontrol.Thephysicalcontrolmechanismsforthecolortuningarealsoexplainedindetail.Thisarticledemonstratesthepotentialapplicationsoftheadaptivefemtosecondpulseshapingtechniqueincontrollingthecoloroutputofdopedrare-earthions.