增加\hspace{10mm}
减少\hspace{-10mm}
\begin{figure*}[t]
\centering
\subfloat[]{\includegraphics[width=2.7in]{a.jpg}
\label{Fig. 1(a)}}\hspace{10mm}
\subfloat[]{\includegraphics[width=2.7in]{b.jpg}
\label{Fig. 2(b)}}
\caption{(a) Examples of experiment 1. (b) Examples of experiment 2.}
\end{figure*}