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简介：文章针对移动无线传感器网络中节点定位的问题,提出利用一个移动锚节点结合DV-Hop算法来对节点进行定位的方法,该算法与静态网络中DV-Hop定位算法相比节约了网络成本,仿真实验表明,该算法的定位误差和定位覆盖率可以满足大多数应用。

简介：VTA涡轮增压器是一种新型的增压器,具有燃油消耗率低和降低排放污染的优点,本文介绍了VTA控制系统,探讨了其工作原理,调整控制程序实现全工况范围内发动机与增压器的最佳匹配,使发动机性能优化以满足客户的需求.并对其运行管理及应用提出了合理的建议.

简介：文章介绍了快速绘制梁的内力图的教学方法，利用该方法学生能够快速掌握绘制内力图的规律，能在不列方程情况下，迅速地绘出复杂外力作用下梁的内力图，并以实例说明该方法的有效性。

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简介：活塞环的工况直接影响主机工作过程的好坏,同时也影响主机的安全运行和使用寿命.文章通过对活塞环工作原理的分析,围绕活塞环密封效用的参数的测定,介绍几种目前在船舶上和船舶修造企业常用的活塞环故障检测方法.

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简介：文章结合某桥梁工程的施工,对现浇连续箱梁跨城市道路的门洞支架进行了设计,并着重对门洞支架的强度、刚度及稳定性进行了验算以确保工程施工的安全,同时阐述了门洞支架搭设的施工要点,为类似工程施工提供了借鉴。

简介：2月1日,交通部海事局党委书记梁晓安到东港海事处督导电煤运输工作。在听取东港海事处关于保障电煤运输工作的汇报后,他肯定了东港海事处为保障电煤运输所采取的措施，并为东港海事处题词——“中国海事电煤运输保障第一处”。梁书记强调，保障电煤运输畅通要政治意识到位，大局意识到位，责任意识到位，要做打硬仗的长期准备，

简介：Theextendingofacantileverandtransversemovingofadrillingfloorenablethejack-uptooperateinseveralwellpositionsaftertheJack-uphaspitched.Thecantileverallowableloadnephogramisthecriticalreferencewhichcanevaluatethejack-up’sdrillingability,designthecantileverstructureandinstructajack-upmanagertomaketheoperationssafe.Theintentofthispaperistoexploretheinterrelationshipsbetweenthecantileverposition,drillingfloorandtheloadsincludingwindforce,thestandset-backweightetc.,throughanalyzingthestructureandloadcharacteristicsofthex-typecantileverandthesimplifiedmechanicsmodelwiththerestrictionofthemaximummomentcapacityofthecantileversinglesidebeam.Referringtoseveraltypicalpositiondesignsloadvalues,thecantileverallowableloadnephogramisobtainedbyusingthesuitableinterpolationmethod.Thepapergivesamethodforcantileverallowableloaddesign,whichisprovedreliableandeffectivebythecalculationexample.

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.