简介：Itispresentedthatthereisapumpingeffectatitsbaseinthedevelopmentprocessofacumulus.Inthestrongeststageofcumulusdevelopment,thepumpingismainlyproducedbythebuoyanceatthebase,andmaybetakenasthefirstapproximationoftheascendingspeedatthebase.Theresultsofnumericalcalculationsandsimulationsoffourobservedradarechoesshowthatasthefirstapproximation,theheightofair-masscumulusmaybesimulatedbyHaltinermodelintheabsenceofob-servedascendingspeedsatthebase,andtheHaltinermodelcanbecharacterizedbythesensitivityofthecumulusdevelopmenttothevirtualtemperatureexcessoverenvironmentatthebase.

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简介：ＳＯＭＥＦＥＡＴＵＲＥＳＯＦＡＮＥＷＧＥＮＥＲＡＴＩＯＮＯＦＵＰＰＥＲ－ＡＩＲＯＢＳＥＲＶＡＴＩＯＮＳＹＳＴＥＭＨｕａｎｇＢｉｎｇｘｕｎ（黄炳勋）ＩｎｓｔｉｔｕｔｅｏｆＡｔｍｏｓｐｈｅｒｉｃＳｏｕｎｄｉｎｇＡＢＳＴＲＡＣＴＳｏｍｅｆｅａｔｕｒｅｓｏｆ...

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简介：Inthiswork,laserinducedtungstenplasmahasbeeninvestigatedintheabsenceandpresenceof0.6Tstatictransversemagneticfieldatatmosphericpressureinair.Thespectroscopiccharacterizationoflaserinducedtungstenplasmawasexperimentallystudiedusingspace-resolvedemissionspectroscopy.Theatomicemissionlinesoftungstenshowedasignificantenhancementinthepresenceofamagneticfield,whiletheionicemissionlinesoftungstenpresentedlittlechange.Temporalvariationoftheopticalemissionlinesoftungstenindicatedthattheatomicemissiontimeinthepresenceofamagneticfieldwaslongerthanthatintheabsenceofamagneticfield,whilenosignificantchangesoccurredfortheionicemissiontime.Thespatialresolutionofopticalemissionlinesoftungstendemonstratedthatthespatialdistributionofatomsandionswereseparated.Theinfluenceofamagneticfieldonthespatialdistributionofatomswasremarkable,whereasthespatialdistributionofionswaslittleinfluencedbythemagneticfield.Thedifferentbehaviorsbetweenionsandatomswithandwithoutmagneticfieldinairwererelatedtothevariousatomicprocessesespeciallytheelectronsandionsrecombinationprocessduringtheplasmaexpansionandcoolingprocess.

简介：TheaimofthisworkisanimprovementoftheparameterizationofthesoilmoistureintheschemeoftheLandSurfaceProcessModel(LSPM)forapplicationsoverdesertareas.Infact,inverydryconditions,thewatervapourfluxplaysanimportantroleintheevaporationprocessesandinfluencestheundergroundprofilesofhumidityandtemperature.TheimprovedversionofsoilmoistureparametcrizationintheLSPMschemehasbeencheckedbyusingthedatatakenfromthedatabaseofthefieldexperimentHAPEX-Sahel(Hydrology-AtmospherePilotExperimentintheSahel,1990-1992).ModelsimulationsrefertothreedifferentstationslocatedinNiger(Fallow,MilletandTigersites)whereinputdataforLSPMandobservationsweresimultaneouslyavailable.TheresultsofsimulationstakingintoaccountthewatervapourfluxinthesoilmodelLSPM,seemtocomparebetterwiththeobservedbehaviourofsoilmoistureandturbulentheatfluxesthanthoseoverlookingthewatervapourflux,confirmingthegreatimportanceofthewatervapourinsuchdryconditions.

简介：Inthispaper,a3Dmagneto-hydrodynamic(MHD)arcsimulationmodelisappliedtoanalyzethearcmotionduringcurrentinterruptioninacertainaircircuitbreaker(ACB).Thedistributionsofpressure,temperature,gasflowandcurrentdensityofthearcplasmainthearcregionarecalculated,andthefactorsinfluencingthecommutationprocessareanalyzedaccordingtothecalculatedresults.Basedontheairflowinthearcchamber,thecausesofarccommutationasynchronyandthebackcommutationareinvestigated.Itindicatesthatareasonablecontactspacedesigniscrucialtoasuccessfularccommutationprocess.Toverifythesimulationresults,theinfluenceofcontactspaceonarcvoltageandarccommutationistested.ThisresearchcanprovidemethodsandreferencestotheoptimizationofACBdesign.

简介：在现在的学习，一个计算液体动力学工作被执行在超声的潮湿的空气喷气由冷凝作用调查冲击波的出现。不稳定的、可压缩的axisymmetric海军司烧方程被TVD(减少的全部的变化)解决在这研究的计划。数字模拟为低压力比率和各种各样的湿度被执行了。结果为低压力比率在超声的潮湿的空气喷气看冲击波的出现马赫磁盘什么时候不发生，取决于空气的湿度。

简介：Thehigh-resolutionWeatherResearchandForecasting(WRF)modeliscoupledtothePrincetonOceanModel(POM)toinvestigatetheeffectofair-seainteractionduringTyphoonKaemithatformedintheNorthwestPacificat0000UTC19July2006.Thecoupledmodelcanreasonablyreproducethemajorfeaturesofoceanresponsetothemovingtropicalcyclone(TC)forcing,includingthedeepeningofoceanmixedlayer(ML),coolingofseasurfacetemperature(SST),anddecayingoftyphoon.DuetotheappearanceofmaximumSSTcoolingtotheleftofthesimulatedtyphoontrack,twopointsrespectivelylocatedtotheleft(16.25N,130.1E,namedasA,themaximumSSTcoolingregion)andright(17.79N,130.43E,namedasB)ofthetyphoontrackaretakenasthesamplingpointstostudythemechanismsofSSTcooling.ThelowtemperatureatpointAhasagoodcorrelationwiththe10-mwindsbutdoesnotpersistforalongtime,whichillustratesthatthetemperaturedroppingproducedbyupwellingisaquickprocess.Althoughthewind-currentresonancecausesoscillationstotheleftoftyphoontrackatpointA,thefluctuationisnotsostrongasthatatpointB.ThethinMLandupwellingproducedbytheEkmanpumpingfromstrong10-mwindsarethemainreasonofmaximumSSTcoolingappearingtotheleftofthetyphoontrack.Duetoweaker10-mwindsandthickerandwarmerMLatpointB,thecolderwaterunderthethermoclineissurpressedandthetemperaturedroppingisnotdramaticwhenthestrongest10-mwindsoccur.Afterwards,thetemperaturegraduallydecreases,whichisfoundtobecausedbytheinertialoscillationsofthewind-currentsystem.

简介：Experimentswereconductedtostudythegenerationofaircoreanditseffectontheoutflowshapeanddischargeinacylindricalwatertankwithabottomwell-designedoutlet.Dependingonthestagesoftheaircoreinthetank,theoutflowshapecanvaryfromasmoothwaterjettoasmoothspindleshapewithair-core,andtowatersprays.Thediameterofthenozzlesizealsohasinfluenceontheoutflowpattern.Theexistenceofthepenetratedaircorecandramaticallyreducetheoutflowdischarge,withthedischargecoefficientdecreasingwiththenozzlediameter.

简介：In4-strokeinternalcombustionengines,air-fuelratiocontrolisachallengingtaskduetotherapidchangesofenginethrottle,especiallyduringtransientoperation.Toimprovethetransientperformance,managingthecycle-to-cycletransientbehaviorofthemassoftheair,thefuelandtheburntgasisakeyissueduetotheimbalanceofcycliccombustionprocess.Thispaperaddressthemodel-basedestimationandcontrolproblemforcyclicair-fuelratioofspark-ignitionengines.Adiscrete-timemodelofair-fuelratioisproposed,whichrepresentsthecycle-to-cycletransientbehaviorofin-cylinderstatevariablesundertheassumptionsofcyclicmeasurabilityofthetotalin-cylinderchargemass,combustionefficiencyandtheresidualgasfraction.Withthemodel,aKalmanfilter-basedair-fuelratioestimationalgorithmisproposedthatenableustoperformafeedbackcontrolofair-fuelratiowithoutusinglambdasensor.Finally,experimentalvalidationresultisdemonstratedtoshowtheeffectivenessofproposedestimationandcontrolschemethatisconductedonafull-scaledgasolineenginetestbench.

简介：与从Shantou和厦门和公民的Doppler雷达数据，环境预言和公民的中心为大气的研究(NCEP/NCAR)分析数据集中，台风Chanchu在2006年5月17日引起的短期的重暴风雨的特征被学习。Doppler雷达数据显示在从1800～19005月17日的时期期间，积极、否定的光线的风最大值的方位角的阶段在台风的核心半径附近是不对称的，即，轨道的左边上的光线的风在右边上比那反常地大。研究证明这被冷空气的侵入导致(在东北弯屈)，它首先在中间降低层被定位，比4km低；这由于强迫空气高举的侵入的冷空气，提高不稳定性精力的版本，它触发重降水。在冷空气活动的迟了的阶段期间，台风很快被削弱。与冷空气的观察雷达的侵入一致，风数据的NCEP/NCAR分析也证明在台风中心(18005月17日)左边在中间降低层(近似1-3km)有明显的大分级的风价值，并且在所有区域除了，侵入的寒冷影响的那些通风--轨道的右边上的风速度在左边上仍然保持比那些大。而且，Rankine模型结果证实在东北冷的空气在轨道左边在中间降低层被介绍给台风。计算也指出那在那里存在有与高度和发生在福建省的南方的超级重暴风雨向西北从东南倾斜到的高se的一个正面的地区就在正面的地区附近躺。

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简介：Whenlocatingtheleakageofthermalfieldofacertaincontainer,itishardforustoevaluatetheleakagewithoneorseveralseparatethermalinfraredimages.Instead,panoramicimagerywithawidevisualangleandhighdistinguishabilityisalwaysneeded.However,wecanonlygetimagesforpartofthescenebecauseofthelimitedvisualfieldofthermographyandthelargesizeofthemeasuredobjectinpractical.Whatismore,thehardwarethatcanbeusedtogetpanoramicimagesisalwaysexpensiveandcannotbeusedinlargescale.Therefore,thispaperintroducesimagemosaictechnology,whichcanbeusedtogettheintactthermalinfraredimageofthemeasuredandincreasetheefficiencyofdetection.Theexperimentresultsdemonstrateitseffectiveness.

简介：Duetoviscousheatingspontaneousignitionofasupersonicflowofpremixedcombustiblegasescanoccurinboundarylayers.Thisprocessisstudiednumericallyforahyedrogen-airmixtureinthecaseofalaminarboundarylayeroveraflatplate.Inapreviousstudythemainstructureofthereactingflowwasgivenaswellasafirstmappingoftheignitionconditionsversusboundaryconditions.Inthepresentworkcomputationsareperformedinordertofurtherspecifythecontrollingmechanismsandparametersofsuchaboundarylayerignition.Weemphasizemorepreciselyi)theelementarystepsofthechemicalprocesswhichefectivelycontroltheignitionii)theunusualroleplayedbytheequivalenceratioofthemixtureiii)theinfluenceoftheSoreteffect(speciestransportduetotemperaturegradients).

简介：1982年,伟大的迈克尔·乔丹和摩西·马龙分别在NCAA和NBA的战场上纵横驰骋、称王称霸;同样是在1982年,伟大的设计师BruceKilgore推出了第一双AirForce1篮球鞋,并进而在篮球鞋这个战场上独占鳌头。如今,25年过去了,在这长达1/4个世纪的时间里,AirForce1非但没有被岁月所淘汰,反而愈发显示出其映照世界的光芒。AirForce1是第一款运用了气垫技术的篮球鞋,大大提高了球鞋的舒适性能、缓冲性能和支撑性能,这对篮球鞋来说堪称一场革命。

简介：1.INTRODUCTIONAcidrainobservationsshowthatacidcloudwaterinShanghairegionappearsnotonly

简介：Theeffectofnozzlegeometryonsoniclineandcharacteristicsofsupersonicairjetwasstudied.Computationalfluiddynamicswasappliedinthisstudy.Theaxisymmetricnozzlegeometriesinvestigatedweretwodifferentcontourconvergingnozzles,twodifferentconicallyconvergingsharp-edgednozzlesandasharp-edgedorifice.Theresultsshowthatthesupersonicjetstructure,soniclineandstreamlinesinsupersonicjetarestronglyinfluencedbythenozzlegeometry,andthetotalpressurelossincreaseswiththeincreaseofMachdiskdiameter.Thepresentnumericalsimulationisaneffectivetooltoevaluatecompressibleflowsinsupersonicairjet.

简介：Whencondensationoccursinsupersonicflowfields,theflowisaffectedbythelatentheatreleased.Inthepresentstudy,Navier-Stokesequationsweresolvednumericallyusinga3rd-orderMUSCLtypeTVDinite-differenceschemewithasecond-orderfractional-stepfortimeintegration,Baldwin-Lomaxmodel,thatisthealgebraicmodel,calledthezeroequationmodelwasusedinthecomputations.Theeffectsofinitialconditions(initialdegreeofsupersaturationandtotaltemperatureinthereservoir)oncondensingflowofmoistairinasupersoniccircularhalfnozzlewereinvestigated.Inthiscase,theeffectofcondensationontheboundarylayerwasalsodiscussedindetail.Asaresultthesimulatedflowfieldswerecomparedwithexperimentaldataingoodagreement,andthevelocityandtemperatureprofileswerelargelychangedbycondensation.

简介：在2008年的MacWorld大会上,苹果公司的CEO斯蒂夫·乔布斯带着一个黄色的牛皮纸信封登场,在众人疑惑不解的目光中,他慢慢从信封内掏出了一台笔记本——MacBookAir,一时之间全场震撼,苹果的创意再次挑战了人们的想象力极限。