  Molecular dynamics simulations have been used to investigate the structures
of Lennard-Jones (LJ) nanowires (NWs) encapsulated by carbon nanotubes (CNTs).
  We found that, when the radius of CNTs is small, the structures of NWs are
quite simple, {\it i.e,} only multishell NWs are formed. For CNTs with larger
radius, the structure of NWs becomes much richer. In addition to crystal and
multishell NWs, three new kinds of NWs are found, {\it i.e,} a hybrid NW with a
crystal core coated by a few shells, a crystal NW with droplet-like pits on the
side of NW, and a multishell NW with droplet-like pits on the side of NW.
  The 'phase' diagram, which describes the structure change with the number of
LJ atoms and the interaction between NWs and CNTs, is also obtained.
