简介：Thispaperstudiesthewall-boundedflowaroundacylindricalatahighReynoldsnumbersbodyinadeterminedcomputationaldomain,withsimulationsofthe3-D,turbulentconcentricannulusflowinastraightpipe.Numericalresultsshowthatareversingzone,appearingasatonguezonewithnestedvelocitieshigherthanthesurroundingarea,existsbehindthecylindricalbody.Theannulusspaceisaregionofhighvelocityandlowpressure.Thezerovelocity,ofcombinedtheX-velocityandtheY-velocity,existsinthecrosssectionsandnovortexsheddingisformedbehindtheattachingcylinders.Amongallinvestigatedeffectingfactors,thediametersoftheattachingandthemaincylindersaffectthewakefeaturebehindthecylindricalbodywhilethemaincylinderlengthdoesnotaffectthedistributiontendencyoftheflowfield.Thediametersofthemaincylinderandthepipeaffectthepressurevaluesandthedistributiontendenciesonthemaincylindersurface.Obviously,theincreaseofthepipediameterreducesthedragcoefficientofthecylindricalbodyandtheincreaseofthediameterofthemaincylinderincreasesthedragcoefficientgreatly.Thenumericalinvestigationoftheconcentricannulusflowprovidesfoundationsforfurtherimprovementsoftheintricateflowstudies.

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：GroundlevelozonepollutionhasbecomeasignificantairpollutionprobleminBeijing.Becauseofthecomplexwayinwhichozoneisformed,itisdifficultforpolicymakerstoidentifyoptimalcontroloptionsonacost-effectivebasis.Thispaperidenti-fiesandassessesarangeofoptionsforaddressingthisproblem.WeapplytheAmbientLeastCostModelandcomparetheeco-nomiccostsofcontroloptions,thenrecommendthemosteffectivesequencetorealizepollutioncontrolatthelowestcost.ThestudyfindsthatinstallingofStageIIgasolinevaporrecoverysystematBeijing's1446gasolinestationswouldbethemostcost-effectiveoption.Overall,optionstoreduceozonepollutionbycuttingve-hicularemissionsaremuchmorecost-effectivethanoptionsto'cleanup'coal-firedpowerplants.

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简介：Anovelsurfacewaveplasma(SWP)sourceexcitedwithcylindricalTeflonwaveguidehasbeendevelopedinourpreviouswork.Theplasmacharacteristicshavebeensimplystudied.Inthiswork,ourexperimentaldevicehasbeensignificantlyimprovedbyreplacingtheTeflonwaveguidewithaquartzrod,andthenbettermicrowavecouplingandhighergaspuritycanbeobtainedduringplasmadischarge.Theplasmaspatialdistributions,bothinradialandaxialdirections,havebeenmeasuredandtheeffectofgaspressurehasbeeninvestigated.Plasmadensityprofilesindicatethatthisplasmasourcecanproduceuniformplasmainanaxialdirectionatlowpressure,whichshowsitspotentialinplasmaprocessingonacurvedsurfacesuchasaninnertubewall.Asimplifiedcircularwaveguidemodelhasbeenusedtoexplaintheprincipleofplasmaexcitation.Thedistinguishingfeaturesandpotentialapplicationofthiskindofplasmasourcewithahardwareimprovementhavebeenshown.

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简介：Verticalprofilesfortheuranium-seriesradioisotopes210Pband210Powereobtainedatthetwohydrothermalventsites,theIheyaRidgeandtheMinami-EnseiKnoll,intheMid-OkinawaTroughin1993and1994,respectively.In1995,bothradioisotopesweremeasuredattheMinami-EnseiKnollagain.AttheIheyaRidge,wherethehydrothermalactivityisnotactiveasreflectedbytheCH4and222Rndata,boththetotal210Pband210Poactivitiesshowdeficiencyrelativetotheirparents,andthemeanresidencetimeof210Pband210Poisapproximatelyequalto20and2～5a,respectively.AttheMinami-EnseiKnoll,whichischaracterizedbyblacksmokers,thetotal210Pb(0.167×10-3～2.5×10-3Bq/kg)aroundtheplumesisdeficientrelativeto226Rabutthetotal210Poactivities(1.83×10-3～2.83×10-3Bq/kg)areinexcessrelativeto210Pb.The210PoactivitiesarehigherthanthoseintheEastChinaSeaandtheOkinawaTroughandexcess210Pohasbeenfound.The210Pb/226Raand210Po/210Pbactivityratiosare0.1～0.4and1.1～7.8,respectively.210Pbispreferentiallyscavengedinthehydrothermalplumes.Thepossiblemechanismsgoverningtheconcentrationof210PbintheMinami-EnseiKnollinvolvealateraltransportof210Pbviadiffusion.Thehigh210Po/210Pbactivityratiosinthehydrothermalplumessuggestadepletionof210Pbandadditionof210Pointhehydrothermalventarea.

简介：TheseparatedturbulentflowaroundacircularcylinderisinvestigatedusingLarge-EddySimulation(LES),Detached-EddySimulation(DES,orhybridRANS/LESmethods),andUnsteadyReynolds-AveragedNavier-Stokes(URANS).Thepurposeofthisstudyistoexaminesometypicalsimulationapproachesforthepredictionofcomplexseparatedturbulentflowandtoclarifythecapabilityofapplyingtheseapproachestoatypicalcaseoftheseparatedturbulentflowaroundacircularcylinder.Severalturbulencemodels,i.e.dynamicSub-gridScale(SGS)modelinLES,theDES-basedSpalart-Allmaras(S-A)andk?ωShear-Stress-Transport(SST)modelsinDES,andtheS-AandSSTmodelsinURANS,areusedinthecalculations.Sometypicalresults,e.g.,themeanpressureanddragcoefficients,velocityprofiles,Strouhalnumber,andReynoldsstresses,areobtainedandcomparedwithpreviouscomputationalandexperimentaldata.Basedonourextensivecalculations,weassessthecapabilityandperformanceofthesesimulationapproachescoupledwiththerelevantturbulencemodelstopredicttheseparatedturbulentflow.

简介：Alargeeddysimulation(LES)oftheflowsaroundanunderwatervehiclemodelatintermediateReynoldsnumbersisperformed.TheunderwatervehiclemodelistakenastheDARPASUBOFFwithfullappendages,wheretheReynoldsnumberbasedonthehulllengthis1.0×105.Animmersedboundarymethodbasedonthemoving-least-squaresreconstructionisusedtohandlethecomplexgeometricboundaries.Theadaptivemeshrefinementisutilizedtoresolvetheflowsnearthehull.Theparallelscalabilitiesoftheflowsolveraretestedonmesheswiththenumberofcellsvaryingfrom50millionto3.2billion.Theparallelsolverreachesnearlylinearscalabilityfortheflowsaroundtheunderwatervehiclemodel.Thepresentsimulationcapturestheessentialfeaturesofthevortexstructuresnearthehullandinthewake.Bothofthetime-averagedpressurecoefficientsandstreamwisevelocityprofilesobtainedfromtheLESareconsistentwiththecharacteristicsoftheflowspassanappendedaxisymmetricbody.Thecodeefficiencyanditscorrectpredictionsonflowfeaturesallowustoperformthefull-scalesimulationsontensofthousandsofcoreswithbillionsofgridpointsforhigher-Reynolds-numberflowsaroundtheunderwatervehicles.

简介：Theflowaroundtwoplateshavingasymmetricbeveledtrailingedgeplacedside-by-sideinauniformstreamwereinvestigatedbothnumericallyandexperimentally.Twoplateswithspacingratioof1.0andbeveledtrailingedgeofangle20oweretestedatReynoldsnumbersequalto3.97×104.Thenumericalsimulationresultsdisplayedthattheflowseparatesononeplatebeveledtrailingedgesurface.Thevortexformationandsheddingfromthisplateledtodeflectingtheflowtowardtheotherplateandconsequentlythewakebehindtheplatesshowedanasymmetricdevelopment.Thephotographsobtainedfromtheflowvisualizationconfirmedthenumericalresultsconcerningtheflowseparationandvortexformation.Itwasalsofoundthatthecomputedpressuredistributiononthetwoplatesurfaceswasdifferent,particularlyonthebeveledtrailingedgesurfacesandontheflatsides.

简介：Experimentalresultsontheinstabilityoftheisothermalnatural-convectionboundarylayeraroundaverticalheatedflatplatearepresented.ItisdemonstratedthatthecharacteristicsoftheinstabilitywaveintheouterlayerisconsistentwiththecalculationofBrewster&Gebhart.Afteraninitialgrowthofitslowfrequencycomponentsatthedownstreamsideoftheturningpointoftheneutralcurve(Gr≈120)itscomparativelyhigherfrequencycomponentsdevelopandbecometurbulentsubsequentlywithabuoyancysubrangeinitspowerspectra.Simultane-ously,inthemeasurementattheinnerlayernearthewallaviscousinstabilitysignalthesameastheTollmien-Schlichtingwavesinordinaryboundarylaycranditssub-harmonicsinamuchhigherfrequencydomainisdiscoveredandaninertialsubrangecanbeobservedinthespectraatGr≈378.6.

简介：我们在Daxiakou在二叠三叠纪的边界附近学习了泥土岩石()在Xingshan的节()，湖北()省，中国。所有泥土岩石被illitemontmorillonite(I/M)支配混合层矿物质，和高温度的六角形的bipyramid(HB)石英和黄铁矿在不同丰富被包含。克莱microspheres甚至在一些床上被发现。结果证明尽管爆发的紧张和爆发中心的位置可能在时期期间变化了，那项暴烈的活动在二叠三叠纪的转变期间在这个区域或在附近的区域是很经常的。经常的暴烈的活动应该是至少一个领先的事件在大二叠三叠纪的转变期间引起生物区系和生态系统的重大周转。

简介：从Lombok岛，印度尼西亚，和包围区域的paleotsunami沉积的年龄决心用210在BATAN雅加达的Pb方法。包括paleotsunami沉积，方法假定那捱过沉积的这的基本理论将导致210Pb丰富。这个方法的原则是计算210在到更深埋葬的沉积的从表面的特别沉积间隔的Pb内容累积。结果然后在以前联合起来的年里被变换成年龄或depositional时间。从GawahPudak的paleotsunami沉积的标明日期的结果(S8?？？

简介：自从他们在东北西藏的高原在查卡金海·莱克区域附近充当对tectonics和气候变化的小规模的似地球形状的单位回答，这篇文章试图学习冲积扇子的geomorpometric特征。我们份量上提取了似地球形状的参数，例如表面区域和邻近QinghaiNan掸人和Ela掸人的冲积扇子的斜坡。在查卡·莱克的冲积扇子划分区域，QinghaiNan掸人的南方，由一个小区域和短长度被展示，但是最大的斜坡。在Ela掸人区域的冲积扇子的似地球形状的参数在尺寸是中间的，并且在金海·莱克的冲积扇子划分QinghaiNan掸人的区域北方有最轻轻的斜坡。和地区性的指责活动分析，我们建议有在QinghaiNan掸人的南方的高斜坡的冲积扇子被沿着QinghaiNan掸人差错，和Ela掸人差错地区戏的罢工滑倒运动指责的颠倒主要控制一个弱角色。由于活跃差错的缺乏，相反，QinghaiNan掸人的金海·莱克区域北方附近的冲积扇子仅仅对地区性的侵蚀，交通，和免职过程作出回应，从而形成相对轻轻的似地球形状的单位。

简介：在这研究，我们导出温度，潮湿，和臭氧的大气的侧面，与表面放射率，皮肤温度，和表面压力一起，从在晴朗天空下面的红外线声音的发光(无云)状况。云客观地被检测用大气红外线在从在高水平的分辨率下面的中等分辨率成像分光辐射函数的相对低的空间分辨率和云面具信息下面更健全；这察觉用空格matching.Newton的非线性的物理反复的解决方案技术被进行被用于放射的转移方程(RTE)同时检索温度侧面，相对湿度侧面，和表面变量。这种技术被为温度和水蒸汽混合比率的weighting功能把特徵向量回归检索的结果用作背景侧面并且用相应反复的形式执行。反复的形式被把变化原则用于RTE获得。我们也比较了与观察的不同类型获得的检索。结果证明检索大气的发出声音的侧面由精确性和分辨率在另外的观察上有大优势。检索侧面能被用来改进数字模型的起始的条件并且在常规观察是稀少的区域使用了，例如高原，沙漠，和海。

简介：Bionicnon-smoothsurfaces(BNSS)canreducedrag.Muchattentionhasbeenpaidtothemechanismofshearstressreductionbyriblets.Themechanismofpressureforcereductionbybionicnon-smoothsurfacesonbodiesofrevolutionhasnotbeenwellinvestigated.InthisworkCFDsimulationhasrevealedthemechanismofdragreductionbyBNSS,whichmayworkinthreeways.First,BNSSonbodiesofrevolutionmaylowerthesurfacevelocityofthemedium,whichpreventsthesuddenspeedupofaironthecrosssection.Sothebottompressureofthemodelwouldnotbedisturbedsharply,resultinginlessenergylossanddragreduction.Second,themagnitudeofvorticityinducedbythebionicmodelbecomessmallerbecause,duetothesculpturing,thegrowthoftinyairbubblesisavoided.Thusthelargemomentofinertiainducedbylargeairbubbleisreduced.Thereductionofthevorticitycouldreducethedissipationoftheeddy.Sothepressureforcecouldalsobereduced.Third,thethicknessofthemomentumlayeronthemodelbecomeslesswhich,accordingtotherelationshipbetweenthedragcoefficientandthemomentumthickness,reducesdrag.

简介：1INTRODUCTIONInflictinghundredsofmillionsyuan(RMB)worthofeconomiclossesannually,strongwindsandtorrentialrainscausedbytropicalcyclonesaretwoofthemajormeteorologicaldisastersexposedinthesoutheasterncoastofChina.MuchefforthasbeendevotedtotheresearchonthepatternsofTCgenesis,evolutionandvariation.

简介：ThisstudyexaminedtherainfallaroundthemiddleandlowerreachesoftheYangtzeRiverandrelatedatmosphericcirculationbyusingNCEPreanalysisdata.Thepurposeofthisstudyistoanalyzetheirdecadalvariationandtherelationshipamongrainfall,atmosphericcirculationaroundEastAsiaandtheENSOepisodes.Currentresultsarepresentedasfollows:(1)VeryclearincreasingtrendoftherainfallaroundthemiddleandlowreachesoftheYangtzeRiverduringtheMeiyuperiodandJunetoJulyisfoundintherecent15years.Meanwhile,thegeopotentialheightat500hPaaroundtheOkhotskSeaalsoholdssimilarincreasingtrend.ItisnoticeablethatENSOepisodestendtooccurmorefrequentlyintherecent15years.(2)AnindexdescribingEastAsiansummermonsooniswellcorrelatedwiththeSSTintheNino-3regioninprecedingautumnintherecent20yearsbutisnotpriortotheperiod.ThismeansthattheElNinophenomenonexertsmoreimpactsonEastAsiansummermonsoonrecently.(3)ThewarmphaseofPDOintherecent20yearsbasicallycoincideswiththeincreasingtrendoftheatmosphericcirculationinEastAsia.

简介：本地人在桥牌附近搜索桥墩是一个活跃研究话题许多十年了。但是很少的研究在本地人上关于冰盖子的影响被进行了在桥桥墩附近搜索现象。盖住的斜槽试验的一系列冰在这研究被进行。在本地人的类型搜索的不同桥墩的形状因素被比较。在冰盖子下面，为半圆形的桥墩的形状因素从0.66∼0.71。三不同不一致的沉积与D500.58公里，0.50公里，和0.47公里的s分别地。冰的二种类型盖住，也就是光滑、不平的盖子，被创造在桥墩附近模仿冰盖子的影响。最大搜索深度在不同条件下面被分析。scour洞的轮廓被阴谋在桥桥墩附近显示出床形态学和沉积免职。在最大值之间的一种实验关系搜索深度，densimetric弗鲁德数字和沉积尺寸被开发。