摘要
The Frenet-Serret formula is used to characterize the constant angle ruled surfaces in R3. When the surfaces are the tangent developmental and normal surfaces, that is, r(s, v) = tr(s) +v(cosα(s) . t(s) +sina(s) . n(s)), it is shown that each of these surfaces is locally isometric to a piece of a plane or a certain special surface. When the surfaces are normal and binormal surfaces, that is, r ( s, v ) = σ ( s ) + v ( cosa ( s ) . n(s) + since(s) . b(s)), it is shown that each of these surfaces is locally isometric to a piece of a plane or a cylindrical surface.
利用Frenet-Serret公式来讨论R3中定常角的直纹面,给出了它们的特征分类.如果定常角曲面是具有r(s,v)=σ(s)+v(cosα(s)·t(s)+sinα(s)·n(s))形式的切线面和法向曲面,则它们局部等距于平面或一类特殊的曲面.如果定常角曲面是具有r(s,v)=σ(s)+v(cosα(s)·n(s)+sinα(s)·b(s))形式的法向曲面和副法向曲面,则它们局部等距于平面或柱面.
基金
The National Natural Science Foundation of China(No.10971029,11101078,11171064)
the Natural Science Foundation of Jiangsu Province(No.BK2011583)