  The electronic structures of zig-zag and arm-chair single-walled carbon
nanotubes interacting with a transitional-metal atomic nanowire of Ni have been
determined. The Ni nanowire creates a large electron density of states (DOS)at
the Fermi energy. The dependence of the enhanced DOS on the spin state and
positioning of the transition-metal wire(inside or outside the nanotube) is
studied. Preliminary estimates of the electron-phonon interaction suggest that
such systems may have a superconducting transition temperature of $\sim$ 10-50
K. The signs of superconductivity seen in ``ropes'' of nanotubes may also be
related to the effect of intrinsic transition-metal impurities.
