简介:Temperature-dependenceandexcitation-intensity-dependenceofphotoluminescencespectraforbothdisorderedandorderedGa0.52In0.48Paremeasured.Thedisorderedsampleischaractierizedbyitssinglepcakphotoluminescencespectrumwhichisexcitation-intensity.independentandhasdifferentactivationenergyatdifferenttemperatureregion.Theorderedsampleshowsdoublepeaks,theintensityofthehigh-energypeakhasananomalousincreasefirstlyandquenchesafterwards.Therelativehenomenaarereasonablyexplainedintermsoflatticeorderingandorientationsuperlatticemodel.
简介:Self-organizedIn0.5Ga0.5As/GaAsquantumislandstructureemittingat1.35μmatroomtemperaturehasbeensuccessfullyfabricatedbymolecularbeamepitaxy(MBE)viacycled(InAs)1/(GaAs)1monolayerdepositionmethod.Photoluminescence(PL)measurementshowsthatverynarrowPLlinewidthof19.2meVat300Khasbeenreachedforthefirsttime,indicatingeffectivesuppressionofinhomogeneousbroadeningofopticalemissionfromtheIn0.5Ga0.5Asislandsstructure.Ourresultsprovideimportantinformationforoptimizingtheepitaxialstructuresof1.3μmwavelengthquantumdot(QD)devices.
简介:Nitridatedβ-Ga_2O_3(100)substratewasinvestigatedasthesubstrateforGaNepitaxialgrowth.Theeffectsofnitridationtemperatureandsurfaceroughnessofβ-Ga_2O_3wafersontheformationofGaNwerestudied.Itwasfoundthatthemostoptimizednitridationtemperaturewas900°C,andhexagonalGaNwithpreferredorientationwasproducedonthewell-polishedwafer.Thenitridationmechanismwasalsodiscussed.
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简介:DNA提取是进行DNA检测的第一步。也是最重要的环节之一。磁珠DNA自动提取系统的出现为DNA提取提供了更为有效的平台,使DNA的提取过程更加简易,操作更加便捷,避免了人为因素带来的误差和污染,在保证提取质量的同时缩短了实验的整体时间,同时使提取更加精确和均一。DNA自动提取工作站与磁珠提取法相结合设计而成的磁珠DNA自动提取系统正逐渐成为DNA提取步骤中被广泛普及和应用的主流方法之一。GA318-32A核酸自动提取仪即是基于磁珠提取法研制而成的一套高通量、高灵敏度的自动核酸纯化提取设备。它可在短时间内利用机器磁棒架上的磁棒,将吸附有核酸的磁珠移动至不同的试剂孔内,经过细胞裂解、核酸吸附、清洗与洗脱,最终得到高纯度核酸。从GA318—32A核酸自动提取仪的结构原理、主要特征、法医学应用等方面进行阐述,以期使该仪器在法医DNA检测中得到更广泛的应用。
简介:摘要:选取P市火车站为研究对象。阐述其布局现状,运用SLP(系统布置设计)方法,分析其物流和非物流关系,得到车站站内各作业单位的综合相互关系表,进行分析得到两种优化布局排布方式,并将该两种布局方式作为遗传算法(GA)的初始种群部分个体,建立客流最低移动成本和作业单位之间相互关系密切程度最高的多目标问题,将多目标问题通过赋予不同权重值转换为单目标函数,并建立目标函数的约束条件,结合带精英策略的遗传算法,使用Matlab软件求解,最终求得布局满意解。通过对比发现,SLP-GA结合所求得的布局满意解,更加满足多目标规划要求,为火车站的布局规划提供更为合理科学的布局方案。
简介:Sheetmetalformingiswidelyappliedtoautomobile,aviation,spaceflight,ship,instrument,andapplianceindustries.Inthispaper,basedonanalyzingtheshortcomingofgeneralfiniteelementanalysis(FEA),theconceptionofparametricfiniteelementanalysis(PFEA)ispresented.Theparametricfiniteelementanalysis,artificialneuralnetworks(ANN)andgeneticalgorithm(GA)arecombinedtoresearchthoroughlyontheproblemsofprocessparametersoptimizationofsheetmetalforming.Theauthorprogramstheoptimizationschemeandappliesitinaresearchofoptimizationproblemofinsidesquareholeflangingtechnologicalparameters.Theoptimizationresultcoincideswellwiththeresultofexperiment.Theresearchshowsthattheoptimizationschemeoffersagoodnewwayindiedesignandsheetmetalformingfield.