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简介：Thispaperpresentsreal-timemonitoringdataandanalysisresultsofthenon-stationaryvibrationsofanoperationalwindturbine.Theadvancedtime-frequencyspectrumanalysisrevealsvariednon-stationaryvibrationswithtimevaryingfrequencies,whicharecorrelatedwithcertainsystemnaturalmodescharacterizedbyfiniteelementanalysis.Undertheeffectsofstrongwindload,thewindturbinesystemexhibitscertainresonancesduetobladepassingexcitations.Thesystemalsoexhibitscertaininstabilitiesduetothecouplingofthetowerbendingmodesandbladeflapwisemodewithbladepassingexcitationsunderthevariationofwindspeed.Ananalyticalmodelisusedtoelaboratethenon-stationaryandinstabilityphenomenaobservedinexperimentalresults.ThepropertiesofthenonlinearinstabilitiesareevaluatedbyusingLyapunovexponentestimation.

简介：全球领先的设备软件优化(DSO)厂商美国风河系统公司(WindRiverSystems．Inc．-NASDAQ：WIND)日前宣布将进一步加速发展车载资讯娱乐系统和telematics标准，并以此推进通信业务共同体(COMET，CommunityEnablingTelematicsObjectives)协作计划在欧洲的实施。WindRive，公司始终致力于为广大电子制造厂商提供高度安全性、

简介：全球领先的设备软件优化(DSO)厂商美国风河系统公司(WindRiverSystems，Inc．-NASDAQ：WIND)日前宣布将进一步加速发展车载资讯娱乐系统和telematics标准．并以此推进通信业务共同体(COMET，CommunityEnablingTelematicsObjectives）协作计划在欧洲的实施。WindRiver公司始终致力于为广大电子制造厂商提供高度安全性、

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简介：请家长帮忙制作背景，使Alfi能在山上自由上下。1在鞋盒里画出高山的场景图。2用铅笔穿透盒子顶部，把线轴套在铅笔上。

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简介：Windshearreflectsthatthewindfieldisnotuniform,whichisoneoftheprimaryfactorswhichmaketheretrievalofthewindfielddifficult.Basedonvolumevelocityprocess(VVP)windfieldretrievaltechnique,theintensityofwindshearisidentifiedinthispaper.Afteranalyzingthetraditionaltechniquesthatrelyonthedifferenceofradialvelocitytoidentifywindshear,afixeddifferenceamongradialvelocitiesthatmaycausefalseidentificationinauniformwindfieldwasfound.Becauseofthenon-uniformityinwindshearareas,thedifferenceofretrievedresultsbetweensurroundinganalysisvolumescanbeusedasameasurementtoshowhowstrongthewindshearis.AccordingtotheanalysisofasevereconvectiveweatherprocessthatoccurredinGuangzhou,itcanbefoundthattheareasofwindshearappearedwiththestrengthsignificantlylargerthaninotherregionsandthemagnitudegenerallylargerthan4.5m/(s·km).Besides,bycomparingthevariationofwindshearstrengthduringtheconvection,itcanbefoundthatnewcellswillbemorelikelytogeneratewhenthestrengthisabove3.0m/(s·km).Therefore,theanalysisofstrongwindshear'smovementanddevelopmentishelpfultoforecastingsevereconvections.

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简介：Theauthorshadinventedtheuniquewindpowerunitcomposedofthelarge-sizedfrontwindrotor,thesmall-sizedrearwindrotorandthepeculiargeneratorwiththeinnerandtheouterrotationalarmatureswithouttheconventionalstator.Thisunitiscalled'IntelligentWindPowerUnit'bytheauthors.Thefrontandtherearwindrotorsdrivetheinnerandtheouterarmatures,respectively,whiletherotationaltorqueiscounter-balancedbetweenbotharmatures/windrotors.Thispaperdiscussesexperimentallytheacousticnoisefromthefrontandtherearwindrotors.Theacousticnoise,inthecounter-rotatingoperation,isinducedmainlyfromtheflowinteractionbetweenbothrotors,andhasthedominantpowerspectrumdensityatthefrequencyofthebladepassinginteraction.Thenoiseiscausedmainlyfromtheturbulentfluctuationduetotheflowseparationontheblade,whentherearwindrotorstopsorrotatesinthesamedirectionasthefrontwindrotor.

简介：Thegeophysicalmodelfunction(GMF)describestherelationshipbetweenabackscatteringandaseasurfacewind,andenablesawindvectorretrievalfrombackscatteringmeasurements.ItisclearthattheGMFplaysanimportantroleinanoceanwindvectorretrieval.TheperformanceoftheexistingKu-bandmodelfunctionQSCAT-1isconsideredtobeeffectiveatlowandmoderatewindspeedranges.However,intheconditionsofhigherwindspeeds,theexistingalgorithmsdivergealarmingly.owingtothelackofinsitudatarequiredfordevelopingtheGMFforthehighwindconditions,theQSCAT-1appearstooverestimatethes0,whichresultsinunderestimatingthewindspeeds.Severalmatch-upQuikSCATandspecialsensormicrowave/imager(SSM/I)windspeedmeasurementsofthetyphoonsoccurringinthewestPacificOceanareanalyzed.TheresultsshowthattheSSM/Iwindexhibitsbetteragreementwiththe'besttrack'analysiswindspeedthantheQuikSCATwindretrievedusingQSCAT-1.Onthebasisofthisevaluation,acorrectionoftheQSCAT-1modelfunctionforwindspeedabove16m/sisproposed,whichusesthecollocatedSSM/IandQuikSCATmeasurementsasatrainingset,andaneuralnetworkapproachasamultiplenonlinearregressiontechnologytechnology.InordertovalidatetherevisedGMFforhighwinds,themodifiedGMFwasappliedtotheQuikSCATobservationsofHurricaneIOKE.ThewindestimatedbytheQuikSCATforTyphoonIOKEin2006wasimprovedwiththemaximumwindspeedreaching55m/s.AnerroranalysiswasperformedusingthewindfieldsfromtheHollandmodelasthesurfacetruth.TheresultsshowanimprovedagreementwiththeHollandmodelwindwhencomparedwiththewindestimatedusingtheQSCAT-1.However,largebiasstillexisted,indicatingthattheeffectsofrainmustbeconsideredforfurtherimprovement.

简介：ThisstudyinvestigatedtheflowcharacteristicsalteredbyJangBogoAntarcticResearchStationusingcomputationalfluiddynamics(CFD)modeling.ThetopographyandbuildingsaroundJangBogoStationwereconstructedwithcomputeraided-designdataintheCFDmodeldomain.Wesimulated16caseswithdifferentinflowdirections,andcomparedtheflowcharacteristicswithandwithoutJangBogoStationforeachinflowdirection.Thewinddatarecordedbythesite’sautomaticweatherstation(AWS)wereusedforcomparison.WindroseanalysisshowedthatthewindspeedanddirectionaftertheconstructionofJangBogoStationwerequitedifferentfromthosebeforeconstruction.Wealsoinvestigatedhowvirtualwindfenceswouldmodifytheflowpatterns,changingthedistanceofthefencefromthestationaswellastheporosityofthefence.Forwesterlyinflows,whentheAWSwasdownwindofJangBogoStation,thedecreaseinwindspeedwasmaximized(-81%forwest-northwesterly).ThewindspeedreductionwasalsogreaterasthedistanceofthefencewasclosertoJangBogoStation.Withthesamedistance,thefencewithmediumporosity(25%–33%)maximizedthewindspeedreduction.Theseresultssuggestthatthelocationandmaterialofthewindfenceshouldbeselectedcarefully,orAWSdatashouldbeinterpretedcautiously,forparticularprevailingwinddirections.

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简介：TosolvetheproblemintheabsenceofpermeabilityalgorithminChina’sforestryindustrystandard"TechnicalSpecificationforOasisShelterBeltConstruction(LY/T1682—2006)",bydefiningandcalculatingtheforeststructuralparameters-porosityβ,stumpagesurfaceporosityS",stumpagevolumeporosityV’,abovegroundsurfaceareadensityC,abovegroundbulkdensityW,therelationsamongthesestructuralparametersandtheirrelationswithwindpermeabilitycoefficientα,shelterbeltwidthDandmeandiameterofbranchdwerecalculated,whichisexpressedas:W=V’/D=dC/4=dS’/4D=-πdlnβ/4D=-0.1πZdlnα/D.Itisproofedthatthemainstructuralparametershavehomogeneityanddifferentstructuralparametersareofinheritanceandconsistencyonthenature,thereisnoexclusivityinthestrictsense,andisconvertibleundercertainconditions,whichisconvenientforevaluatingthewind-resistanceeffectofshelterbelt.AsetofcomputationalformulasforwindeffectevaluationoffarmlandshelterbeltindryandsandyareainnorthernChinaisderived.

简介：Thispaperpresentsanapplicationofgain-scheduling(GS)controltechniquestoafloatingoffshorewindturbineonabargeplatformforaboveratedwindspeedcases.Specialemphasisisplacedonthedynamicsvariationofthewindturbinesystemcausedbyplantnonlinearitywithrespecttowindspeed.Theturbinesystemwiththedynamicsvariationisrepresentedbyalinearparameter-varying(LPV)model,whichisderivedbyinterpolatinglinearizedmodelsatvariousoperatingwindspeeds.Toachievecontrolobjectivesofregulatingpowercaptureandminimizingplatformmotions,bothlinearquadraticregulator(LQR)GSandLPVGScontrollerdesigntechniquesareexplored.ThedesignedcontrollersareevaluatedinsimulationswiththeNREL5MWwindturbinemodel,andcomparedwiththebaselineproportional-integral(PI)GScontrollerandnon-GScontrollers.ThesimulationresultsdemonstratetheperformancesuperiorityofLQRGSandLPVGScontrollers,aswellastheperformancetrade-offbetweenpowerregulationandplatformmovementreduction.

简介：英国奔瑞公司宣布其MillenniuM系列新增全球领先的新铜缆布线系统CAT6Plus。CAT6Plus可优化系统性能，并满足未来系统的需要。CAT6Plus全面兼容ClassD／Cat-egory5／5e系统，是同类产品中的佼佼者。