Figure 4

Right-side image: a TEM image of a FNT wrapping around carbon membrane of a TEM grid, left-side image: close-up of the red square shown in the TEM image showing a barbell-like cross section of FNT.
Right-side image: a TEM image of a FNT wrapping around carbon membrane of a TEM grid, left-side image: close-up of the red square shown in the TEM image showing a barbell-like cross section of FNT.