  We consider two particles of spin-1/2 interacting with a one-dimensional
N-spin array, which is an exactly solvable model. The dynamics of entanglement
and quantum discord (QD) of the spins of the two particles is investigated by
regarding the 1D N-spin array as the environment. It is found that although the
entanglement may suffers a sudden death and a sudden birth in the evolution, it
can neither be generated nor become larger than its initial value. Different
from the entanglement dynamics, QD can be amplified, and even be generated by
the interaction between particles and the common environment. We also observe
that QD decays asymptotically to zero and later experiences a rival when the
average number of excitation in the 1D N-spin array becomes larger in the case
of nonzero inter-distance between two particles.
