Thin films of poly(methyl methacrylate)/polystyrene (PMMA/PS 80/20 W/W) blend prepared on glass substrate by spin-coating from a cosolvent, chloroform were studied. The formation of regular Voronoi patterns was found ...Thin films of poly(methyl methacrylate)/polystyrene (PMMA/PS 80/20 W/W) blend prepared on glass substrate by spin-coating from a cosolvent, chloroform were studied. The formation of regular Voronoi patterns was found under phase contrast microscopy (PCM). It was observed that there were clear concave boundaries in the PCM images by atomic force microscopy (AFM). Although the sample was annealed at 220℃ more than 7 h, no changes of the Voronoi pattern occurred, implying that the phase separation structure in the Voronoi pattern was almost complete during spin-coating process. It was believed that the formation of this pattern was due to the convection during spin-coating procedure.展开更多
介绍自然单元法(NEM)在处理二维弹性力学问题中的应用.该方法利用求解点的自然邻接点和V orono i结构构造整体近似位移函数,且在求解区域的D e launay三角形子域上采用G a lerk in过程建立整体求解的系统平衡方程,其积分可在背景三角形...介绍自然单元法(NEM)在处理二维弹性力学问题中的应用.该方法利用求解点的自然邻接点和V orono i结构构造整体近似位移函数,且在求解区域的D e launay三角形子域上采用G a lerk in过程建立整体求解的系统平衡方程,其积分可在背景三角形网格上采用数值积分得到.展开更多
文摘Thin films of poly(methyl methacrylate)/polystyrene (PMMA/PS 80/20 W/W) blend prepared on glass substrate by spin-coating from a cosolvent, chloroform were studied. The formation of regular Voronoi patterns was found under phase contrast microscopy (PCM). It was observed that there were clear concave boundaries in the PCM images by atomic force microscopy (AFM). Although the sample was annealed at 220℃ more than 7 h, no changes of the Voronoi pattern occurred, implying that the phase separation structure in the Voronoi pattern was almost complete during spin-coating process. It was believed that the formation of this pattern was due to the convection during spin-coating procedure.