  Refined structures of blowup for non-collapsing maximal solution to a
semilinear parabolic equation are studied. We will prove that the blowup set is
empty for non-collapsing blowing-up in subcritical case, and all finite time
non-collapsing blowing-up must be type II in critical case. When
p>p_S=(N+2)/(N-2) for N>=3, the Hausdorff dimension of the blowup set for
maximal solution whose energy is non-collapsing is shown to be no greater than
N-2-4/(p-1), which answers a question proposed in [7] positively. At the end of
this paper, we also present some new examples of collapsing and non-collapsing
blowups.
