A wave-breaking mechanism for solutions
with certain initial profiles and propagation speed are discussed in
this paper. Firstly, we apply the best constant to give sufficient
condition via an appropriate integral form of the initial data,
which guarantees finite time singularity formation for the
corresponding solution, then we establish blow up criteria via the
conserved quantities. Finally, persistence properties of the strong
solutions are presented and infinite propagation speed is also
investigated in the sense that the corresponding solution $u(x,t)$
does not have compact spatial support for $t>0$ though $u_0 \in
C_0^{\infty}(\mathbb{R})$.