简介：本文所讨论的积图是图的笛卡尔积，图的张量积，图的逻辑积和图的强直积四种积图．证明了：①如果Ｇ１和Ｇ２都是连通图，则积图中笛卡尔积，逻辑积和强直积都是道路正图．②图的张量积是道路正图的是图Ｇ１和Ｇ２是一个连通图，Ｇ１［或Ｇ２］有一个奇圈，且ｍａｘ｛λ１μ１，λｎμｍ｝≥２，其中λ１和λｎ［或μ１和μｍ］分别是图Ｇ１或Ｇ２的最大和最小特征值

简介：Longlastingstrontiumaluminatephosphorsweresynthesizedbymeansofcoatedprecipitationintheexperiment.SrA12O4monoclinicphasewithlongafterglowwassynthesizedat1100℃withtheaidofH3BO3,andthesynthetictemperaturedecreasedabout100℃-150℃thaninsolidstatereaction.TheprocessofheattreatmentwasstudiedbyTG-DTA.ThephasecompositionsofpowderswereanalyzedbyXRD.ThemicrographsofthesampleswereinvestigatedbySEMandtheluminescentpropertieswereresearchedbyopticalspectrum.TheeffectsofH3BO3onthephasecompositionandmicrostructureofthecalcinedpowderswereinvestigated.TheresultsindicatedthatH3BO3acceleratedtheformationofSrAl2O4byconsumingtheintermediatephase.TheadditionofDy2O3stimulatedtheafterglowpropertyduetotheincreaseinthedepthofthetrapcenterinthematerials.