deletions | additions       diff --git a/introduction.tex b/introduction.tex  index 16e74d9..dffc27b 100644  --- a/introduction.tex  +++ b/introduction.tex 
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\begin{equation}  m \frac{d^2 x}{d^2 t} + \Gamma \frac{dx}{dt} + \omega_p^2 x = e^* \left(\frac{V_{applied}}{l}\right)  \end{equation}  where $m$ is the collective mass of CDW, $\Gamma$ the damping coefficient, $l$ the length of the 1D conducting channel in the  crystal and $\omega_p$ is the pinning characteristic frequency. Solution to equation (3) by replacing $V_{applied}$ by $V_{dc}+V_{ac} \space cos(\omega t)$ gives the resonance contribution and will be discussed in detail later. The other model for CDW depinning is the semiconductor tunneling analogy\cite{Zener_1934}. The CDW motion was considered to be tunneling through the pinning potential and the tunneling potential was found to be  \begin{equation}