  Let $A$ be a finite dimensional hereditary algebra over a field $k$ and
$A^{(1)}$ the duplicated algebra of $A$. We first show that the global
dimension of endomorphism ring of tilting modules of $A^{(1)}$ is at most 3.
Then we investigate embedding tilting quiver $\mathscr{K}(A)$ of $A$ into
tilting quiver $\mathscr{K}(A^{(1)})$ of $A^{(1)}$. As applications, we give
new proofs for some results of D.Happel and L.Unger, and prove that every
connected component in $\mathscr{K}({A})$ has finite non-saturated points if
$A$ is tame type, which gives a partially positive answer to the conjecture of
D.Happel and L.Unger in [10]. Finally, we also prove that the number of arrows
in $\mathscr{K}({A})$ is a constant which does not depend on the orientation of
$Q$ if $Q$ is Dynkin type.
