简介:观展读史前不久,由中国博物馆协会航海博物馆专业委员会主办、中国运河文化博物馆承办的国内首届“匠心问舟——‘海上丝绸之路’中式木帆船模型展览”在山东聊城中国运河文化博物馆隆重开幕。此次中华传统木帆船船模大展,集中展示了中国历史上发明创造的各种船型,涵盖了我国传统木帆船的沙船、浙船、福船、广船等主要航海船型以及一些具有独特地域特征的“通江达海”的内河航行船型。如上海沙船、汴河客船、南湖红船、绿眉毛船、丹阳船、川江麻秧子船、山东长岛大瓜篓船、牵风船、巢湖划子船、福建泉州湾宋代海船、山东菏泽元代沉船、天津张湾明代运河漕船复原船及清代广东大澳船等。
简介:针对大雁塔周边地铁3、4线竣工后,将北广场单行组织改为双向交通,对该段部分路段的渠化与是否设置信控等问题进行确定;解决现状组织方案中的问题、应用Synchro、VISSIM进行方案的设计和评价,通过对比得知:允许芙蓉东路存在左转向交通、并于乐游路口设置信号,这一方案可将平均延误控制在35s上下,停车总数由现状的1409次减少至1165次,使路口的服务水平维持在A~C之间;其研究方法和手段可以为该类问题的解决提供经验.
简介:Acomplianttowerismodeledasapartiallydry,partiallytapered,dampedTimoshenkobeamwiththesuperstructuremodeledasaneccentrictipmass,andanon-classicaldampedboundaryatthebase.Thefoundationismodeledasacombinationofalinearspringandatorsionalspring,alongwithparallellinearandtorsionaldampers(Kelvin-Voigtmodel).Thesuperstructureaddstothekineticenergyofthesystemwithoutaffectingthepotentialenergy,therebyreducingthenaturalfrequencies.Theweightofthesuperstructureactsasanaxialcompressiveloadonthebeam,reducingitsnaturalfrequenciesfurther.Theemptyspacefactorduetothetruss-typestructureofthetowerisincluded.Theeffectofsheardeformationandrotaryinertiaareincludedinthevibrationanalysis;withthenon-uniformbeammode-shapesbeingaweightedsumoftheuniformbeammode-shapessatisfyingtheendcondition.TheweightsareevaluatedbytheRayleigh-Ritz(RR)method,andverifiedusingfiniteelementmethod(FEM).Theweightofthesuperstructureactsasanaxialcompressiveloadonthebeam.Kelvin-Voigtmodelofstructuraldampingisincluded.Apartofthestructurebeingunderwater,thevirtualaddedinertiaisincludedtocalculatethewetnaturalfrequencies.Aparametricstudyisdoneforvariousmagnitudesoftipmassandvariouslevelsofsubmergence.ThecomputationalefficiencyandaccuracyoftheRayleigh-Ritzmethod,ascomparedtotheFEA,hasbeendemonstrated.Theadvantageofusingclosed-formtrialfunctionsisclearlyseenintheefficacyofcalculatingthevariousenergycomponentsintheRRmethod.