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\section{Introduction}   When quasi-ID materials such as NbSe$_3$ undergo the Peierls transition \cite{Peierls_1956}, the charge density in the conduction band fluctuates according to the lattice potential. With larger potential distortion in the lattice, say, the cations form dimers changing the lattice spacing changes from $a$ to $2a$, the electrons tend to pile up around the two close cations, analogous to the bounding state in the molecules. If external DC voltage is applied, the CDW is pinned near the lattice potential on the site until the external voltage exceeds the threshold voltage and CDW starts to move. The DC conductivity was given empirically as the following expression\cite{Bardeen_1979}. \begin{equation}  \sigma_{dc}(E) = \sigma_a + \sigma_b\space exp(-\frac{E_0}{E})  \end{equation}  The motion is described as CDW tunneling through an energy gap