想实现这样的一个表格表头样式：
采用如下的代码
\documentclass[preprint,10pt,authoryear]{elsarticle}
\usepackage{geometry}
\geometry{left=2cm, right=2cm, top=2cm, bottom=2cm}
\usepackage{microtype}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{amsmath}
\usepackage{caption}
\makeatletter % “@” is now a normal letter for TeX
\def\@makecaption#1#2{%
\vskip\abovecaptionskip
\sbox\@tempboxa{#1 #2}%
{\bfseries #1} #2\par
\vskip\belowcaptionskip}
\makeatother
\usepackage{booktabs}
\usepackage[justification=centering]{caption}
\begin{document}
\begin{table}
\caption{\newline The results of running algorithm parallel using MapReduce.}
\begin{tabular}{llllllp{4.84cm}}
\hline
Node Prop & CPU(GHz) & RAM(GB) & No. of nodes & No. of map functions & Threshold computing time(s) & \multicolumn{1}{p{4.84cm}}{\centering Memory cell generation time(s)} \\
\hline
Serial & 250GHz & 1GB & 1 & – & 131 & \multicolumn{1}{p{4.84cm}}{\centering 168} \\
Test case 2 & & & & & & \multicolumn{1}{p{4.84cm}}{\centering} \\
Test case 3 & & & & & & \multicolumn{1}{p{4.84cm}}{\centering} \\
Test case 4 & & & & & & \multicolumn{1}{p{4.84cm}}{\centering} \\
Test case 5 & & & & & & \multicolumn{1}{p{4.84cm}}{\centering} \\
\hline
\end{tabular}\\
\end{table}
\begin{table}[ht]
\centering
\begin{minipage}[t]{0.6\linewidth}
%\centering
\makeatletter\def\@captype{table}\makeatother\caption{\newline The concept pair number of different settings of $k^{‘}$.}
\label{hit k’}
\begin{tabular}{l|ccccc}
\toprule
&M\&C&R\&G&WS353-Sim&Wikipedia2015\\
\hline
$k^{‘}=1$&23&49&167&22\\
$k^{‘}=2$&7&16&34&8\\
$k^{‘}=3$&0&0&2&0\\
sum&30&65&203&30\\
\bottomrule
\end{tabular}
\end{minipage}
\end{table}
\end{document}
效果：
