简介:当企业越来越趋于理性时,CRM项目的投资回报率(ROI)就成为不得不考对ROI的量化分析可以适当简化,只需考虑CRM项目的总成本、总收益及项目的时间跨度等三个主要因素.在此基础上进行项目实施前的ROI与预期实施后的ROI比较,就可以确保项目的真正成功.
简介:为了研究船用工程复合材料的界面裂纹特性,建立了刚性一压力敏感粘弹塑性材料I型准静态扩展裂纹的力学模型.在稳态扩展阶段,应力和应变具有相同的奇异量级,即(σ,ε)∝r^-1/(n-1).引入Airy应力函数,通过渐近分析得出了裂纹尖端应力和应变的分离变量形式的渐近解,并采用打靶法求得了裂纹尖端应力和应变的数值结果.数值计算结果表明,界面裂尖场主要受材料的泊松比和幂硬化指数的控制.通过对裂纹尖端场的渐近分析,从应变角度出发,提出了刚性-压力敏感性材料界面I型准静态扩展裂纹的断裂判据.
简介:Wavediffractionoftwoconcentricporouscylinderswithvaryingporositywasstudiedbyusingananalyticalmethodbasedoneigenfunctionmatching.Thefluiddomainaroundthecylindersisdividedintothreesub-domainsandineachsub-domainaneigenfunctionexpansionofthevelocitypotentialisobtainedbysatisfyingtheLaplaceequation,theboundaryconditionsonthefreesurfaceandontheseabed.Theunknowncoefficientsofeigenfunctionexpansionsaredeterminedbyboundaryconditionsontheporoushulls.Inthepaper,theboundaryconditionsarebasedupontheassumptionthattheflowintheporousmediumisgovernedbyDarcy’slaw.Twoporous-effectparametersappliedontwoporouscylindersarefunctionsoftheverticalcoordinateinsteadoftheconstant.Waveloadingontheouterandinnercylinderispresentedinthenumericalresults.
简介:Theprogressofeconomicglobalization,therapidgrowthofinternationaltrade,andthemaritimetransportationhasplayedanincreasinglysignificantroleintheinternationalsupplychain.Asaresult,worldwideseaportshavesufferedfromacentralproblem,whichappearsintheformofmassiveamountsoffuelconsumedandexhaustgasfumesemittedfromtheshipswhileberthed.Manyportshavetakenthenecessaryprecautionstoovercomethisproblem,whileothersstillsufferduetothepresenceoftechnicalandfinancialconstraints.Inthispaper,thebarriers,interconnectionstandards,rules,regulations,powersources,andeconomicandenvironmentalanalysisrelatedtoships,shore-sidepowerwerestudiedineffortstofindasolutiontoovercomehisproblem.Asacasestudy,thispaperinvestigatesthepracticability,costsandbenefitsofswitchingfromonboardshipauxiliaryenginestoshore-sidepowerconnectionforhigh-speedcraftscalledAlkaherawhileberthedattheportofSafaga,Egypt.Theresultsprovidethenationalelectricitygridconceptasthebesteconomicalselectionwith49.03percentofannualcostsaving.Moreover,environmentally,itcouldachieveanannualreductioninexhaustgasemissionsofCO2,CO,NOx,P.M,andSO2by276,2.32,18.87,0.825and3.84tons,respectively.
简介:针对船舶动力系统润滑油水分检测耗时长的问题,根据润滑油导电性随含水率变化的特点,设计出基于电导传感器的润滑油水分在线、实时检测系统,系统通过获得电导传感器测量油水混合液的输出电压计算润滑油的含水率。该仪器主要包括电导传感器与激励源模块、单片机STM32F103C8模块、信号采集模块和液晶显示模块等构成。实验结果表明电导传感器润滑油水分检测系统能够准确、方便、快速地实现检测功能。
简介:对大连海事大学图书馆航海、轮机技术学科类中文图书2001~2004年的流通和利用情况作了统计,应用文献流通率和文献利用率进行分析,并提出整改建议.