\begin{table}%t5
\caption{Emission measures, $EM$, in units of $10^{57}~ {\rm cm}^{-3}$.}
\label{em}
\small
%\centerline
{\begin{tabular}[bottom]{cccccc}
\hline\hline
\noalign{\smallskip}
MJD & Phase & \ion{N}{v} & \ion{Si}{iv} & \ion{C}{iv} & Note \\
\noalign{\smallskip}
\hline
44~831 & 0.506 & 140 & 31 & 22 & (1) \\
          &          & 2.8 & 2.6 & 1.8 & (2) \\
49~271 & 0.696 &      & 24 & 21 & (1) \\
          &          &      & 2.0 & 1.7 & (2) \\
\noalign{\smallskip}
\hline
\end{tabular}}
(1)  $T_{\rm e}=15~000~ {\rm K}$; (2)  $g(T)=0.7 g_{\rm max}(T)$.
\end{table}