什么叫圆形壳的R-L型振动

tangjikede

我在看一篇关于纳米管波动的论文时，看到这样一句话：
The first difference is that the phase velocity for the first R–L mode in the axisymmetric mode represents a uniform variation at smaller wavenumbers, but a nonuniform variation is found for other motions at nonzero m.  (Application of nonlocal elastic shell theory in wave propagation analysis of carbon nanotubes. Smart Mater. Struct. 16 (2007) 178–190)
不知道什么意思.
谢谢！