  We have examined the efficiency of baryon-number transport mechanism across
the phase boundary in a cosmological quark-hadron phase transition through the
proper estimate of baryon-number penetrability $<\Sigma_h>$. For this purpose
we have derived first the double-pair creation probability $P_b$ in terms of
single-pair creation probabilty per unit time and unit volume $\kappa_m$ and
then obtained an analytical expression for $<\Sigma_h >$. Our calculation is
free from the uncertainty of the value of double-pair creation probability per
unit time and unit volume $\kappa_b$ which was used as a free parameter in
earlier calculations. Finally the variations of double-pair creation
probability $P_b$ as well as $<\Sigma_h>$ with temperature are shown and
compared with other known results.
