学科分类
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22 个结果
  • 简介:本文详细论述了高速接入技术的热点---CableModem技术的概念、特点、工作方式、技术标准及实际应用,着重从Internet高速接入方面作了介绍,并指出该技术蕴含的巨大发展潜力。

  • 标签: CABLE MODEM HFC 有线电视 宽带接入
  • 简介:本文较为详细地介绍了如何通过wingate代理软件,来共享cablemodem宽带上网的安装与配置操作.因它源于实践中摸索出的经验,因此具有较好的实用价值.

  • 标签: wingate代理软件 配置操作 共享
  • 简介:Theapproximateeigenfrequenciesforthein-planevibrationsofacablestruc-tureconsistingofinclinedcables,togetherwithpointmassesatvariouspointswerecom-puted.Itwasdiscoveredthattheclassicaltransfermatrixmethodwasinadequateforthistask,andhencethelargerexteriormatriceswereusedtodeterminetheeigenfrequencyequation.Thenpredictionsofthedynamicsofthegeneralcablestructurebasedontheasymptoticestimatesoftheexteriormatricesweremade.

  • 标签: 特征频率分析 矩阵转换 外部矩阵 电缆结构
  • 简介:TheREapplicationinaluminumbasealloy,auniquebranchofREapplicationinmetallurgyinChi-na,hasdevelopedrapidly.Boththeoutputandtech-niqueareinaleadingpositionintheworld.Particular-ly,theREapplicationinpowertransmissioncablehasmadeaconsiderableprogress.UptonowChinacanfabricatethreekindsofRE-containingconductors.Oneisahighconductivitycon-ductor;theothertwoarehighstrengthandheat-re-

  • 标签: FABRICATE METALLURGY ductor branch CABLE PROPORTION
  • 简介:Boththeinplaneandout-of-planetransversevibrationsofaviscoelasticcablesubjectedtoaninitialstressdistributinguniformonthecrosssectionarestudied.Theconstitutionofthecablematerialisas-sumedtobeofthehereditaryintegraltype.Thepartialdifferential-integralequationsofmotionarederivedfirst.ThenbyapplyingGalerkin’smethod,thegoverningequationsarereducedtoasetofsecond-ordernon-lineardifferential-integralequationswhicharesolvedbyfinitedifferencenumericalintegrationprocedures.Finally,theeffectsoftheviscosityparameterandtheelaslicparameteronthetransientamplitudesofthefirstmodeareinvestigatedbynumericalsimulation.

  • 标签: VISCOELASTIC cable SMALL SAG INTEGRAL CONSTITUTIVE
  • 简介:AsimplifiedfragilityanalysisoffantypecablestayedbridgesusingProbabilisticRiskAnalysis(PRA)procedureispresentedfordeterminingtheirfailureprobabilityunderrandomgroundmotion.Seismicinputtothebridgesupportisconsideredtobeariskconsistentresponsespectrumwhichisobtainedfromaseparateanalysis.Fortheresponseanalysis,thebridgedeckismodeledasabeamsupportedonspringsatdifferentpoints.Thestiffnessesofthespringsaredeterminedbyaseparate2Dstaticanalysisofcable-tower-decksystem.Theanalysisprovidesacoupledstiffnessmatrixforthespringsystem.Acontinuummethodofanalysisusingdynamicstiffnessisusedtodeterminethedynamicpropertiesofthebridges.Theresponseofthebridgedeckisobtainedbytheresponsespectrummethodofanalysisasappliedtomultidegreeoffreedomsystemwhichdulytakesintoaccountthequasi-staticcomponentofbridgedeckvibration.Thefragilityanalysisincludesuncertaintiesarisingduetothevariationingroundmotion,materialproperty,modeling,methodofanalysis,ductilityfactoranddamageconcentrationeffect.ProbabilityoffailureofthebridgedeckisdeterminedbytheFirstOrderSecondMoment(FOSM)methodofreliability.Athreespandoubleplanesymmetricalfantypecablestayedbridgeoftotalspan689m,isusedasanillustrativeexample.Thefragilitycurvesforthebridgedeckfailureareobtainedunderanumberofparametricvariations.Someoftheimportantconclusionsofthestudyindicatethat(i)notonlyverticalcomponentbutalsothehorizontalcomponentofgroundmotionhasconsiderableeffectontheprobabilityoffailure;(ii)groundmotionwithnotimelagbetweensupportexcitationsprovidesasmallerprobabilityoffailureascomparedtogroundmotionwithverylargetimelagbetweensupportexcitation;and(iii)probabilityoffailuremayconsiderablyincreaseforsoftsoilcondition.

  • 标签: 地震 成因分析 地层学 地球构造
  • 简介:Three-dimensionalnonlinearaerodynamicstabilityanalysiswasappliedtostudytheaerodynamicstabilityofacable-stayed-suspension(CSS)hybridbridgewithmainspanof1400meters,andtheeffectsofsomedesignparameters(suchasthecablesag,lengthofsuspensionportion,cableplanearrangement,subsidiarypiersinsidespans,thedeckform,etc.)ontheaerodynamicstabilityofthebridgeareanalyticallyinvestigated.Thekeydesignparameters,whichsignificantlyinfluencetheaerodynamicstabilityofCSShybridbridges,arepointedout,andbasedonthewindstabilitythefavorablestructuralsystemofCSShybridbridgesisdiscussed.

  • 标签: 空气动力学 稳定性 钢缆斜拉桥 跨度 参数设计
  • 简介:1前言近年来,宽带接入在国内蓬勃发展,如电信的ADSL、长城宽带的以太接入、广电的CM接入及无线接入.对于各种接入方法的优劣,很多文章做了大量的介绍,在此不多做介绍.各行各业携各自的接入优势,均想在宽带接入市场上占有一席之地.

  • 标签: 电缆调制解调器 接入方法 通信网 宽带接入
  • 简介:<正>Accordingtopressreports,China’sfirstlongdistance,extra-highvoltagecableisexpectedtocrossQiongzhouStraitsbefore2006.

  • 标签:
  • 简介:Inisnecessarytostudydynamicoperationefficiencyoftransmissionnetworksinordertorealizehighintensificationofcommunicationnetworks.Theoperationefficiencydiscussedhereshouldexistnotinlogic-circuitlayer,butalsoinbothpathlayerandmediumlayer.Atheoreticalmethodofthemeasurementoflayersanscomprehensiveevaluationsispresentedbasedontheconceptoftransmissionefficiency.

  • 标签: 传输网络 逻辑电路 路径系统 光缆 纤心 操作率
  • 简介:Inordertoresolvethetrafficcongestionproblem,manycable-stayedbridgesaredesignedwithalargewidthtospanratio.Thisresultsinsignificantshearlageffecttocausenonuniformstressdistributionalongtheflangesofthebeamofbridge.ThispaperreportsstudyontheshearlageffectoftheLanzhouXiaoxihuYellowRiverBridge.A3Dfiniteelementmodelofthebridgewasdevelopedandfiniteelementanalysis(FEA)wasdonetoobtainthetheoreticalresults.Toevaluatethetheoreticalresults,ascaledmodelwasmadetoconductstatictestinlaboratory.TheexperimentresultsaccordedwiththeresultsobtainedbyFEA.ItisprovedthatFEAisaneffectivemethodtopredictshearlageffectofbridgesofthistype.

  • 标签: 钢缆斜拉桥 FEA 跨度 剪切力 有限元分析 压力分布
  • 简介:电报网支持了在点点的最先进的技术支持了的玻璃窗帘人玻璃窗帘墙,广泛地在中国被使用。因为它在风负担下面的大偏转和高非线性,电缆线网络的动态性能是极大地与常规线性结构的不同。连续的膜理论被用来构造非线性的颤动电报网的微分方程,和泛音平衡方法被用来解决非线性的频率的分析公式。为了验证上述分析公式,公式的结果和非线性的女性的时间历史方法的精确性,被比较并且发现了在好同意。而且,微分方程和非线性的频率在这篇论文获得了的非线性的颤动是在波动的风负担下面的一张电报网的wind-inducedresponse分析的基础。

  • 标签: 玻璃幕墙 索式结构 几何非线性 非线性振动 频率