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We use rotation of one D-brane with respect to the other to reveal the hidden
structure of D-branes in type-II theories. This is done by calculation of the
interaction amplitude for two different parallel and angled branes. The
analysis of strings with different boundary conditions at the ends is also
given. The stable configuration for two similar branes occurs when they are
anti-parallel. For branes of different dimensions stability is attained for
either parallel or anti-parallel configurations and when
dimensions differ by four the amplitude vanishes at the stable point. The
results serve as more evidence that D-branes are stringy descriptions of
non-perturbative extended solutions of SUGRA theories, as low energy
approximation of superstrings.
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