  We have investigated the acceleration of the unbound high energy particles
moving along the rotation axis in the Kerr-Taub-NUT spacetime, and then study
the dependence of the repulsive effects on the NUT charge for the particles in
the spacetime. Whether the repulsive effects with the NUT charge become
stronger depends on the Carter constant, the position and velocity of the
particles themselves. We also present numerically the changes of the observable
velocity and acceleration with the NUT charge for the unbound particles in the
Kerr-Taub-NUT spacetime.
