\begin{table}%t3
  %\centering
\par
  \caption{Naming scheme for the spectra contained in the library.}
  \label{tab3}
  %\begin{center}
\par
  \begin{tabular}{c l l}
  \hline\hline
  \noalign{\smallskip}
  \multicolumn{3}{c}{example: ~~T04000G45M05V015K2ANWNVR20F.asc}\\
  &&\\
  {characters} &         & {meaning}    \\                    
  &&\\
    1--6      & T04000  & $T_{\rm eff}$ (K)\\
    7--9      &  G45    & 10 $\times \log{g}$ (cgs units)\\
     10       &   M     & sign for metallicity: M = "$-$'', P = "+''\\
   11--12     &   05    & 10 $\times$ [M/H]\\
   13--16     &  V015   & rotational velocity (km s$^{-1}$)\\
   17--18     &   K2    & microturbulent velocity (km s$^{-1}$)\\
     19       &   A     & [$\alpha$/Fe] enhancement: S = 0.0, A = +0.4 \\
   20--21     &   NW    & NW = new ODF models, \\
              &         & OD = old ODF models\\
   22--23     &   NV    & no overshooting\\
   24--26     &   R20   & R20 = resolving power 20~000;\\
              &         & RVS = resolving power 11~500 (GAIA);\\
              &         & RAV = resolving power 8500 (RAVE);\\
              &         & SLN = resolving power 2000 (SLOAN);\\ 
              &         & D01 = 1 \AA/pix dispersion; \\
              &         & D10 = 10 \AA/pix dispersion\\ 
     27       &   F     & F = fluxed spectrum (erg  cm$^{-2}$~s$^{-1}$ \AA$^{-1}$ )\\
              &         & N = normalized spectrum\\
   \hline
  \end{tabular}
  %\end{center}
\par
  \end{table}