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简介：AbstractInfection of humans by Powassan virus (POWV) occurs rarely but is potentially life-threatening. First isolated in Ontario, Canada in 1958, the presence of POWV has been confirmed in three countries: Canada, the USA, and Russia. Although a limited number of human cases has been reported thus far, the infection rate has shown signs of increasing during the 21st century. Interestingly, POWV and a genetically close variant, deer tick virus (DTV), are the only member of the tick-borne flaviviruses known to be endemic in North America and maintain in respective tick-host cycles. In this review, we briefly summarize current knowledge involving the epidemiology and etiology, pathogenesis and immunity, molecular evolution, and protein functions of POWV, aiming to increase our understanding of the virus and unlock the potential to control this lethal pathogen. These data may also provide tools to minimize the future threat of other emerging and re-emerging viruses.

简介：AnewSuboptimalMaximumLikelihoodEstimation(SMLE)algorithmbasedonfull-derampmodelanditsimplementationinsatellite-borneradaraltimeterarepresented,withemphasisontheinfluenceofboththereturnfluctuationandthereceivernoiseonheightandslopeestimationprecision.Someconclusionsareobtainedandverifiedbycomputersimulation.

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

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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：(1)Chinaisvastinterritoryandrichinnaturalresources.Ithasdiversifiedpopula-tionanditsenergyresourcesareunevenlydistributed.Inthepastmorethantenyears,therehasbeenagreatgapbetweende-mandandsupplyinelectricity.Inordertosolvethisproblem,theChineseGovern-mentpaysgreatattentiontodevelopwindenergyandnewenergypoliciesofsuitabletothelocalconditions,multi-functionsfor

简介：Withtheadvancesof数字天气模拟和更新的减少的数据吸收骑车，表面观察数据吸收在数据吸收系统变得越来越重要。一个更好的数据吸收系统应该在表面层包含热力学的进程的限制，这广泛地被接受。在这份报纸，因此，一个新表面风观察操作员在全球、地区性的吸收预言System_3D变化(GRAPES_3D-Var)被利用，与在行星的边界层(PBL)的热力学的过程的限制。为了研究这新表面的能力，在吸收弯屈观察操作员并且预报，一系列实验被使用GRAPES模型操作。主要结果显示表面风观察操作员的这个新方法与GRAPES模型一起在预报上有积极影响。

简介：Windpowerpredictioniscrucialtotheoperationofthepowersystemaccommodatingalargeamountofwindpower.Fromtheperspectiveofpowerdispatch,thispaperdiscussesthecurrentsituationsofthetechnology,systembuilding,predictionerrors,theindexforevaluatingwindpowerpredictionsystemandthemainbodiesresponsiblefortheprediction.Itdelvesintotheexistingproblemssuchasincompletebasicdata,poorpredictionaccuracy,shortpredictiontimescale,aswellaslackingofpredictioninmostwindfarms.Suggestionsonimprovementareproposedincludingenhancingtheconstructionofwindpowerpredictionsystemonboththegridsideandthewindfarmside,speedingupthedevelopmentofultra-shorttermwindpowerpredictionsystem,deepeningtheresearchonwindpowerpredictiontechnology,strengtheningtheconstructionoftechnicalstandardsystemandcarryingoutcross-sectorcooperation.