The smallest carbon nanotube High-resolution electron microscope image of a 4A tubule(side walls are marked by lines) confined inside an 1 8-shell carbon nanotube Sumio Iijima et al Nature408,50(2000) 多层碳纳米管 nm 4AThe smallest carbon nanotube High-resolution electron microscope image of a 4 Å tubule (side walls are marked by lines) confined inside an 18-shell carbon nanotube Sumio Iijima et al Nature 408, 50 (2000) 多层碳纳米管