  Transport through two quantum dots laterally embedded in Aharonov-Bohm
interferometry with infinite intradot and arbitrary interdot Coulomb repulsion
is analyzed in the weak coupling and Coulomb blockade regime. By employing the
modified quantum rate equations and the slave-boson approach, we establish a
general dc current formula at temperatures higher than the Kondo temperature
for the case that the spin degenerate levels of two dots are close to each
other. We examine two simple examples for identical dots - no doubly occupied
states and no empty state. In the former, completely destructive coherent
transport and phase locking appear at magnetic flux $\Phi=\Phi_{0}/2$ and
$\Phi=0$ respectively; in the latter, partially coherent transport exhibits an
oscillation with magnetic flux having a period of $\Phi_0$.
