学科分类
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500 个结果
  • 简介:Thispaperpresentsalaboratorystudyonbridgepierprotectionwithsurfaceguidepanels(SGP)inclear-waterexperiments.TheSGPisinstalledbypiercingasetoftwoverticalpanelspartiallyintothewater,withsomeinteriorangleandleadingopening,settingatadistanceaheadoftheprotectedpier.ThesuitableinstallationoftheSGPcaneffectivelyadjusttheflowpatterntoreducethedownflowmotionandthehorseshoevortexaheadofthepier.WeconsidersomedominantfactorstosetupSGPforpierprotection,includingtheinteriorangleθ,leadingopeningOw,distancebetweenpanelandpierL,submergeddepthofpanelPd,pierdiameterDandwaterdepthH.Afterevaluationoftheseparametersthroughlaboratorytests,theoptimalsetupconditionsofθ=60o,Ow/D=0.1~0.2,L/D=2~2.5andPd/H=0.7aredetermined.Undertheseconditions,theusageofSGPleadstoabestperformanceondecrementofthemaximumscourdepthatpierupto90%withignorablesideeffectsontheSGPscour.

  • 标签: 桥墩 冲刷保护 SGP 表面控制面板 河流速度
  • 简介:Basedonthe1stordercnoidalwavetheory,thewavediffractionaroundthepiergroupinshallowwaterisstudiedinthispaper.Theformulasforcalculatingthenonlinearwaveforcesarealsopresentedhere.Inordertoverifythetheoreticalresults,modeltestsareconductedinthewaveflumeinTheStateKeyLaboratoryofCoastalandOffshoreEngineeringlocatedinDalianUniversityofTechnology.TherangeofthewaveparametersintheexperimentsischaracteristicwaveperiodTg/d1/2=8.08-22.86,characteristicwaveheightH/d=0.10.45.Theresultsobtainedfromtheexperimentsagreewiththetheoreticalresultsquitewell.Itisshownthat,inshallowwaterthenonlinearwaveforcesactingonapiergrouparegreaterthanthosecalculatedbylinearwavetheory,thevalueofincrementinwaveforceincreaseswiththeincreasesofthenonlinearityofthewave.Inthewaverangestudiedinthispaper,thenonlinearwaveforcecanreachover4timestheforcecalculatecdbylinearwavetheory.Thus,itissuggestedthat,whenTg/d1/2>8,thewaveforceonthepiersinthepiergroupinshallowwatershouldbecalculatedbyusingthecnoidalwavetheory.

  • 标签: CYLINDER PIER GROUP WAVE FORCE SHALLOW
  • 简介:-Generallythetoeofthebankslopeinfrontofthepile-supportedpierhastobedredgedtomeettherequirementsofwaterdepthfortheberthofships,whilethetopoftheslopeinrearofthepiermustbebackfilledandelevatedtomakeconnectionswithlandtransportation.Thenthenaturalstateofequilibriumoftheslopeisdestroyed,andsomedeformationanddisplacementareunavoidablyinducedinthesoilmasswhichwillexertanundesirableinfluenceonthepilefoundationofthepier.Thisisatypicalproblemoftheinteractionbetweentheso-called"passivepile"andsurroundingsoil,andhasbeenscarcelystudiedintheliteratureofgeotechnicalengineering.Inthispaper,fieldobservation,modeltestsandnumericalanalysisconductedbytheauthorstostudytheinteractionbetweenpile-supportedpierandbankslopearebrieflydescribedandsomepreliminaryresultsarepresented.

  • 标签: INTERACTION PASSIVE PILE PIER SLOPE
  • 简介:Mobileoffshoredouble-causewaypiersystem,atypeofseashoreunloadingequipment,consistsoftwogroupsofmultipleconnectedsemi-submersiblemodules.Thisstructurehaswideapplicationbecausemostofthemiddleorminitypeofvesselsandshipscanbemooredtoit.Basedontheanalysisofcomputationalmethodsofmulti-bodymotionresponse,ahydrodynamicmodelissetupandthethree-dimensionalpotentialtheoryinfinitedepthisadoptedtocalculatethethree-dimensionalmotionresponseofthissystem.ThedoubleP-Mspectrumisusedtoanalyzethemotionresponseinirregularwaves.Differentwavedirectionsarespeciallytakenintoconsideration,duetotheirvariouseffectstothemotionresponse.Furthermore,thecalculatedresultiscomparedwiththatoftheexperiment,anditisprovedthatsway,heave,pitchandyawmotionaregreatlyconstrainedbymooringsystem.Thecomparisonalsoindicatesthatthemodelcanforecastthemotionperformanceofthetarget,andthatthecalculatedresultcanalsobeusedasreferenceinconnectorandmooringsystemdesign.

  • 标签: 海面移动桥墩系统 多漂浮体 P-M光谱 水力分析
  • 简介:Sincelocalscouratbridgepiersinriversandestuariesisamajorcauseofbridgefailure,estimationofthemaximumlocalscourdepthisofgreatimportancetohydraulicandcoastalengineers.Althoughnumerousstudiesthatfocusonscour-depthpredictionhavebeendoneandpublished,understandingoftheflowandturbulencecharacteristicsofthehorseshoevortexthatdrivesthescourmechanisminadevelopingscourholestillisimmature.Thisstudyaimstoquantifythedetailedturbulentflowfieldinadevelopingclear-waterscourholeatacircularpierusingParticleImageVelocimetry(PIV).Thedistributionsofvelocityfields,turbulenceintensities,andReynoldsshearstressesofthehorseshoevortexthatforminfrontofthepieratdifferentscourstages(t=0,0.5,1,12,24,and48h)arepresentedinthispaper.Duringscourdevelopment,thehorseshoevortexsystemwasfoundtoevolvefromoneinitiallysmallvortextothreevortices.Thestrengthandsizeofthemainvortexarefoundtoincreasewithincreasingscourdepth.TheregionsofboththemaximumturbulenceintensityandReynoldsshearstressarefoundtoformatalocationupstreamofthemainvortex,wherethelargeturbulenteddieshavethehighestpossibilityofoccurrence.Resultsfromthisstudynotonlyprovidenewinsightintothecomplexflow-sedimentinteractionatbridgepiers,butalsoprovidevaluableexperimentaldatabasesforadvancednumericalsimulations.

  • 标签: SEDIMENT transport SCOUR Bridge PIER PIV
  • 简介:到控制的各种各样的方法在桥牌附近搜索墩被建议了。在现在的学习,电报或领子和领子的应用程序试验性地被检验,作为对在光滑的圆形的桥墩的本地搜索的反措施,近到一致沉积运动的开始的阀值流动条件。结果证明电报和领子的同时的使用在减少scour深度有高效率。最好的配置被作出对有利的裁决0.15的电缆线码头直径比率和15的线角度???????????????????????六?栠摹潲潬楧??????????吗??

  • 标签: 局部冲刷 同时使用 电缆 桥墩 衣领 冲刷深度
  • 简介:Two-andthree-dimensionalfiniteelementanalysisprogramsforpile-soilinteractionarecompiled.Duncan-Chang'sModelisused.Theconstructionsequenceofthepierismodeled.Thepile-soilinterfaceelementisused.Theinfluenceofthecombinationtypeofpilesonthedeformationofbankslopeandpilebehaviourisanalyzed.Differentdesignsofapile-supportedpierarecomparedthoroughly.Calculationresultsshowthatthestressesanddisplacementsofthepilearedirectlyrelatedtothedistancefromthebankslopeandthedirectionofinclination.Aninclinedproppilesetintherearplatformwouldremarkablyreducethestressesofpilesandthedisplacementofthepier.

  • 标签: INTERACTION pile-supported PIER BANK SLOPE NUMERICAL
  • 简介:Thepier,placedattheoutletofthepressureflowsection,isaneffectivedesigntodealwiththeproblemsofthemanufactureandoperationofthegatesforadischargetunnelwithhighwaterhead.Itiscrucialtocontrolthewater-wing,inducedbythistypeofthepier.Throughobservingthephenomenaofthewater-wing,thereasonofthewater-winginception,i.e.,theconcaveoftheflowsurface,waspresented,andatypeofthenewpierwithbottomunderlaywasdesigned.Thehydrauliccharacteristicsofthepier,includingthevariationsofthewater-wingfeatures,bothlengthandheight,withthewaterhead,aswellaswiththeconcavedepth,andwiththeheightofthebottomunderlay,andthevariationsoftheconcavedepthwiththeheightofthebottomunderlay,wereinvestigatedbyphysicalmodelexperiments.Theresultsshowthattheapproachofthemodificationoftheconcavethroughthestructureswiththebottomunderlay-typepierisremarkablyeffectiveinthewater-wingcontrol.

  • 标签: 水力特性 泄洪洞 水动力学 研究
  • 简介:Inthisstudy,avariationalapproachtothesettlementanalysisofanaxiallyloadedpierem-beddedinamulti-layeredsoilprofileispresented.Inthismethod,thesoilprofileandtheembeddedpieraredividedintoanumberofsub-layersaccordingtotheactualnumberofsoillayersobservedinthefield.ThedisplacementshapefunctionofeachsoillayerisgivenasaproductofanexponentialequationalongthepierdepthandtheBessel’ssolutionintheradialdirection.Thedisplacementrelationshipamongthelayerscanbederivedthroughthetransformationmatrices.Oneofthemajorfeaturesofthismethodisthatthetotalnumberofpierelementsisthesameasthatofsoilsub-layers.Allthefieldcompontents,suchasthedisplacement,stress,andstraininthesoil,canbecalculatedbyclosed-formsolutionsexceptthattheonlyunknownvari-ableisthevalueβwhichcanbedeterminedbyiterationtechniques.Comparisonsweremadewiththeresultsoffiniteelementanalysisandthefieldobservationinpile-loadedtests.

  • 标签: PIER PILE SETTLEMENT ELASTICITY vertieal LOAD
  • 简介:一条高效轨道和抓住(T/H)电路设计因为高分辨率的高速度的analog-to-digital变换器(模数转换器)被介绍,它在0.18m互补金属氧化物半导体过程被实现了。一改善自举,切换体积的技术被介绍极大地在宽带宽,和增加上最小化采样网络的非线性一修改预先控告减少全部的电源消费的电路帮助。试验性的结果证明建议T/H电路以100MHz采样率完成超过77dBSFDR(假免费的动态范围)和70dBTHD(全部的泛音失真)并且当消费47mW电源时,与输入频率维持性能直到305MHz。

  • 标签: 高速ADC 充电电路 高分辨率 性能 跟踪 CMOS工艺
  • 简介:作为生物识别技术重要手段之一的虹膜技术.因其高度的准确性及无需进行人体接触等特点.逐渐在国内外得到广泛应用。L1—ID公司的PIER—T^TM便携式虹膜登记及识别设备是经久耐用、成本效益好的虹膜数据采集识别系统,使操作者可利用高度独特的人类虹膜样式和纹理进行人员登记和识别。根据该设备的设计,在操作时可连接主机电脑或笔记本电脑。

  • 标签: 识别设备 便携式 虹膜 笔记本电脑 生物识别技术 识别系统
  • 简介:嗨,朋友,想和我一起去吃"HighTea"吗?什么?"高茶"?这是什么意思?意思是茶被放在很高的桌子上吗?哈哈,不是的。它和"下午茶"的意思十分相近。我只是想和你去吃些点心!

  • 标签: 英语 阅读材料
  • 简介:剪下页面左下角的奶牛,使其翻过山顶,到达山下的挤奶棚。按照Twinkle,TwinkleLittleStar的曲调演唱这首歌。移动奶牛,沿着花朵翻越山顶,使奶牛到达山下的挤奶棚。上山时,音调逐渐升高;下山时,音调逐渐降低。

  • 标签: 小学 英语教学 教学方法 阅读教学
  • 简介:电话不通小high总喜欢在别人面前炫耀自己认识很多名人,一天早上,他看到阿拉雷正走向自己的办公室,立即拿起电话。“是的,您早!特地打电话给我实在不敢当。什么?今天吗?很抱歉,我今天跟大使有约了,改天我们再约好吗?非常抱歉!”

  • 标签: 幽默 中学 课外阅读 阅读材料 《电话不通》
  • 简介:ThistalkwillsummarizetherecentworkrelatedtoakindofnewnanomaterialsproducedbytheSMAT(surfacemechanicalattritiontreatment).Theconceptofsurfacenanocrystallizationofmaterialswillbepresented.Intermsofthegrainrefinementmechanisminducedbyplasticdeformation,anovelsurfacemechanicalattrition(SMA)techniquewasdevelopedforsynthesizingananostructuredsurfacelayeronmetallicmaterialsinordertoupgradetheoverallpropertiesandperformance.ThegrainrefinementmechanismofthesurfacelayerduringtheSMAtreatmentwillbeanalyzedintermsofthenanostructureobservationsinseveraltypicalmaterials.Veryhighyieldstress(5timesofthebasematerial)onthesurfacelayerofthematerialobtainedbytheSMAThasbeenobserved.Theeffectofsurfacenanostructuresonthemechanicalbehaviorandonthefailuremechanismofmetallicmaterialshowsthepossibilitytodevelopanewstrengthgradientcompositeusingco-rollingandnitriding.Theroleofresidualstressinducedduringthetreatmentwillbeinvestigatedanddiscussed.Thedevelopedmaterialsarealsoporosityfreematerialswhichcanbeusedasreferencematerialforthelocalmechanicalbehaviorinvestigationtechniquesuchasthenanoindentation.Ageneralconceptforobtaininghighstrengthandhighductilitynanostructuredmaterialswillbepresented.Theexceptionalhighstrengthandhighductilitysteelshavedeveloped.Thesimulationofthemechanismsforimprovingductilityofhighstrengthnanostructuredmaterialswillbepresented.Thepotentialapplicationsforthelandtransportationvehicles(car,bus,train)andwindenergyhavebeeninvestigated.Someexamplesofconceptdesignfortheintegrationoftheadvancednanostructuredsteelswillbepresented.

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  • 简介:ASchwarzschildmicroscopewithanumericalapertureof0.2andamagnificationof130ina100μmfieldofview(FOV)isdesignedandisworkingat13.5nm.Meanwhile,aCCDisusedasadetectorwithapixelsizeof13μm×13μmandimagingareaof13mm×13mm.Theimagingqualitywithtolerancesofsystemanderrorsofmirrorsareconsidered.Weobtainthatthebeston-axesobjectresolutioncanbeuptoabout200nm,theaveragevalueis230nm,andtheresolutionisabout360nmat80μmFOV.

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