简介：

简介：La-dopedSr-hexaferrite(Sr_(1-x)La_xFe_(12)O_(19))(x=0.05,0.10,0.15,0.20)nanopowderswithparticlesizerangingfrom80to110nmweresuccessfullysynthesizedbysol-gelauto-combustion.Thephaseformationtemperatureincreases,whiletheparticlesizedecreasesastheLadopingcontentgoesup.ThepartialsubstitutionofSr~(2+)byLa~(3+)resultsinthesuppressioneffectsonthegrowth-upofthecrystallitesandtheenhancementoftheelectronhoppingbetweenFe~(3+)withdifferentvalences,whichleadstotheimprovementinthedielectriclossandmagneticloss.Therefore,boththemicrowaveabsorbingabilitiesandabsorbingfrequencyrangesaretunedbyLa-doping.ThesynthesizedSr-hexaferritenanopowderswithdopingelementcontentof0.10demonstratethefinebroadmicrowaveabsorbingproperties.

简介：AutoCAD软件应用及其专用周课程具有很强的实践性与应用性，为了进一步提高学生机械零件图识图能力与绘图能力，本文探索了在Pro-E三维实体模型的指导下，对二维零件图结构、形状、特征的详细地分析的教学方法。课堂教学结果表明：增强了同学们机械零件的识图能力，提高了同学们机械零件的绘图能力。