简介:Thepolymerizationof1-octeneinitiatedbymethylalumoxane(MAO)-activatedNi(Ⅱ)-based-α-diiminecomplexes[(2,6-i-Pr)_2C_6H_3-DAB(An)]NiBr_2wasinvestigated.Usingthiscatalyst,poly(1-octene)swithmolecularweightbetween100×10~3and400×10~3andpolydispersity(M_w/M_n)between1.3and1.5weresynthesizedsuccessfullybyvaryingreactiontimeatroomtemperature.Thepoly(1-octene)swereamorphouspolymersandcouldbewellsolubleintetrahydrofuran(THF).Afterfractionalprecipitation,poly(1-octene)swithnarrowmolecularweightdistributions(M_w/M_n≤1.12)wereobtained.Theirweight-averagemolecularweightsweremeasuredbygelpermeationchromatography(GPC)inconjunctionwithonlinemodelBI-MwAmultianglelaserlightscattering(MALLS),andtheirintrinsicviscositiesweremeasuredbyMaron'ssingle-pointmethod.ThekandavaluesinMark-Houwinkequation[η]=KM~αinTHFat40℃were0.089mL/gand0.61respectively.
简介:通过对一组聚乳酸样品的凝胶渗透色谱(GPC)和特性粘度〔η〕的测定,应用直线最小二乘拟合的方法,订定了聚乳酸在丙酮中,25℃下的Mark-Houwink方程参数。结果:k=1.672×10-4,α=0.703。将这一结果运用到GPC谱图的计算,所得的粘度值(〔η〕)与用粘度法实测值比较,最大偏差小于493%
简介:Twain describes a town that had been famous for its honesty". In the end,when his daughters were young and he was prospering. His The Adventures of Tom Sawyer was a story about "bad boys,"I see no great difference between a man and a watch
简介:TheMarkVlietriversystemtransportsbedmaterialandpollutedsuspendedsedimentstotheVolkerakZoomlake,awaterenvironmentofhighlimnologicalvalue.Toprotecttheliving,workingandrecreationareasinthiscatchment,aproperintegratedwatermanagementisessential.Asystematiccontrolandsanitationofthepollutedsedimentsintheriverenvironmentwillhelptostopfurtherdegradationofthewaterecosystemquality.Therefore,atransboundarycollaborationbetweenBelgianandDutchauthoritiesissetuptostudyandsanitatethisinterregionalrivercatchment.Toimprove?
简介:Twain describes a town that had been famous for its honesty". In the end,when his daughters were young and he was prospering. His The Adventures of Tom Sawyer was a story about "bad boys,"I see no great difference between a man and a watch
简介:TherecenttwodecadeshaveseenagreatincreaseofOriginalEquipmentManufacturing("OEM")businessinChina.OEMproductsareusedexclusivelyforexportpurposeandretailedinforeignmarketslabelledasthepurchasingcompany’sbrand.However,whethertheuseofatrademarkinthiscircumstanceconstitutesthe"use"inTradeMarkLawandwhatevidenceisneededtojustifythe"use"inanycontinuousthree-yearperiodhavebeenthefocalpointsofdebateregardingtheappropriatecompassofTradeMarkLaw.Loomingbehindtheuncertaintyofthelegalterm-"use"andinconsistentstandardsadoptedbyadministrativeauthoritiesandcourtsareunidentifiedriskstobetakenbyOEMoperators.
简介:摘要:在印刷电路板(PCB)的自动光学检测设备(AOI)中,标志点(Mark点)不可或缺。PCB上料时会出现偏移和旋转,元器件检测的图像需要进行矫正对准,需要通过Mark点对PCB的元器件起到辅助定位、修正的作用,提高元器件检测的精度。本文主要研究两种常用的Mark点定位方法,以及Mark点定位前的图像预处理方法。通过图像去噪、图像锐化和直方图均衡化对Mark点图像进行预处理;对圆形Mark点采用圆拟合方式、对异形或丝印Mark点采用NCC模板匹配的方式进行识别定位,输出定位坐标。该识别方法目前已得到PCB-AOI上应用。
简介:摘要:在印刷电路板(PCB)的自动光学检测设备(AOI)中,标志点(Mark点)不可或缺。PCB上料时会出现偏移和旋转,元器件检测的图像需要进行矫正对准,需要通过Mark点对PCB的元器件起到辅助定位、修正的作用,提高元器件检测的精度。本文主要研究两种常用的Mark点定位方法,以及Mark点定位前的图像预处理方法。通过图像去噪、图像锐化和直方图均衡化对Mark点图像进行预处理;对圆形Mark点采用圆拟合方式、对异形或丝印Mark点采用NCC模板匹配的方式进行识别定位,输出定位坐标。该识别方法目前已得到PCB-AOI上应用。