本文档中有两幅图。第二幅图使用 minipages 将其子图与表格放在一起（如这个答案)，遗憾的是第二个表的子图没有标记为 ab 而是 cd；可能是因为它们被错误地看作是第一个图的一部分（如上所示）。
\documentclass{article}
\usepackage[demo]{graphicx}
\usepackage[labelformat=simple]{subcaption}
\renewcommand\thesubfigure{(\alph{subfigure})}
\renewcommand\thesubtable{(\alph{subtable})}
\usepackage{array}
\usepackage[all]{xy}
% for \extrasrrowheight
%\usepackage{siunitx}
\begin{document}
\begin{figure}
\centering
%ERC1
\begin{subfigure}[b]{0.4\textwidth}
\[
\xymatrix{
*+[o][F]{C^*} \ar@<-.5ex>[d]_{k_{a1}(R-x_1-x_2)} \\
*+[o][F]{x_1 }\ar@<-.5ex>[u]_{k_{d1}}
}
\]
\caption{Single binding configuration}
\label{ERC1diagram}
\end{subfigure}
%ERC2
\begin{subfigure}[b]{0.4\textwidth}
\[
\xymatrix{
&*+[o][F]{C^*} \ar@<-.5ex>[dl]_{k_{a1}(R-x_1-x_2)} \ar@<.5ex>[dr]^{k_{a2}(R-x_1-x_2)} & \\
*+[o][F]{x_1 }\ar@<-.5ex>[ur]_{k_{d1}} & & *+[o][F]{x_2 }\ar@<.5ex>[ul]^{k_{d2}}
}
\]
\caption{Two binding configurations}
\label{ERC2diagram}
\end{subfigure}
\caption[Compartmental diagram of the effective rate constant model]{Compartmental diagram of the ERC model with concentration of analyte at the reaction chip's surface $C^*$, and concentrations of bound analyte $x_1(t)$ and $x_2(t)$.}
\label{ERCdiagram}
\end{figure}
\noindent
\begin{figure}
\centering
%VIs
\begin{minipage}[b]{0.45\textwidth}
%\begin{subfigure}[b]{0.45\textwidth}
\includegraphics[width=\textwidth]{ERC_Kd_varies_a2.png}
\captionof{subfigure}{Association phase}
\label{Lng1AssPhase}
%\end{subfigure}
\end{minipage}
\begin{minipage}[b]{0.45\textwidth}
%\begin{subfigure}[b]{0.45\textwidth}
\includegraphics[width=\textwidth]{ERC_Kd_varies_d3.png}
\captionof{subfigure}{Dissociation phase}
\label{Lng1AssPhase}
%\end{subfigure}
\end{minipage}\\
\begin{minipage}[b]{1\textwidth}
%\begin{subfigure}[b]{1\textwidth}
\centering
\includegraphics[scale=1.2]{ERC_kd_varies_legend4.png}
\end{minipage}%{subfigure}
\caption{Graphs of bound antibody $x_1$ against time $t$ for the Langmuir single configuration model (green dashed line) and the ERC model for different values of $k_m$.}
%\captionof{figure}{Graphs of bound antibody $x_1$ against time $t$ for the Langmuir single configuration model (green dashed line) and the ERC model for different values of $k_m$.}
\label{fig:kc_varies}
%\end{figure}
%\begin{table}
\vspace{\floatsep}
\centering
\footnotesize
\begin{tabular}
{ | c | c | c | c | c | }
\hline
Parameter &$k_{a}$ & $k_{d}$ & $R$ & $C_T$ \\
&M$^{-1}$s$^{-1}$ &s$^{-1}$& pg nm$^{-2}$ & nM \\\hline
Value &6E-4 &7E-3 & 500 & 100 \\\hline
\end{tabular}
\captionof{table}{Values taken by parameters in Fig. \ref{fig:kc_varies} that are not varied}
\label{tab:LwTsols}
\end{figure}
\end{document}
答案1
\captionof仅适用于浮动环境（例如figure或 ）table，而不适用于子环境（例如subfigure或 ）subtable。不幸的是，这会导致奇怪的行为和错误的格式，而不是错误消息。[1]
改用\subcaption：
\documentclass{article}
\usepackage[demo]{graphicx}
\usepackage[labelformat=simple]{subcaption}
\renewcommand\thesubfigure{(\alph{subfigure})}
\renewcommand\thesubtable{(\alph{subtable})}
\usepackage{array}
\usepackage[all]{xy}
% for \extrasrrowheight
%\usepackage{siunitx}
\begin{document}
\begin{figure}
\centering
%ERC1
\begin{subfigure}[b]{0.4\textwidth}
\[
\xymatrix{
*+[o][F]{C^*} \ar@[d]_{k_{a1}(R-x_1-x_2)} \\
*+[o][F]{x_1 }\ar@[u]_{k_{d1}}
}
\]
\caption{Single binding configuration}
\label{ERC1diagram}
\end{subfigure}
%ERC2
\begin{subfigure}[b]{0.4\textwidth}
\[
\xymatrix{
&*+[o][F]{C^*} \ar@[dl]_{k_{a1}(R-x_1-x_2)} \ar@[dr]^{k_{a2}(R-x_1-x_2)} & \\
*+[o][F]{x_1 }\ar@[ur]_{k_{d1}} & & *+[o][F]{x_2 }\ar@[ul]^{k_{d2}}
}
\]
\caption{Two binding configurations}
\label{ERC2diagram}
\end{subfigure}
\caption[Compartmental diagram of the effective rate constant model]{Compartmental diagram of the ERC model with concentration of analyte at the reaction chip's surface $C^*$, and concentrations of bound analyte $x_1(t)$ and $x_2(t)$.}
\label{ERCdiagram}
\end{figure}
\noindent
\begin{figure}
\centering
%VIs
\begin{minipage}[b]{0.45\textwidth}
%\begin{subfigure}[b]{0.45\textwidth}
\includegraphics[width=\textwidth]{ERC_Kd_varies_a2.png}
\subcaption{Association phase}
\label{Lng1AssPhase}
%\end{subfigure}
\end{minipage}
\begin{minipage}[b]{0.45\textwidth}
%\begin{subfigure}[b]{0.45\textwidth}
\includegraphics[width=\textwidth]{ERC_Kd_varies_d3.png}
\subcaption{Dissociation phase}
\label{Lng1AssPhase}
%\end{subfigure}
\end{minipage}\\
\begin{minipage}[b]{1\textwidth}
%\begin{subfigure}[b]{1\textwidth}
\centering
\includegraphics[scale=1.2]{ERC_kd_varies_legend4.png}
\end{minipage}%{subfigure}
\caption{Graphs of bound antibody $x_1$ against time $t$ for the Langmuir single configuration model (green dashed line) and the ERC model for different values of $k_m$.}
%\captionof{figure}{Graphs of bound antibody $x_1$ against time $t$ for the Langmuir single configuration model (green dashed line) and the ERC model for different values of $k_m$.}
\label{fig:kc_varies}
%\end{figure}
%\begin{table}
\vspace{\floatsep}
\centering
\footnotesize
\begin{tabular}
{ | c | c | c | c | c | }
\hline
Parameter &$k_{a}$ & $k_{d}$ & $R$ & $C_T$ \\
&M$^{-1}$s$^{-1}$ &s$^{-1}$& pg nm$^{-2}$ & nM \\\hline
Value &6E-4 &7E-3 & 500 & 100 \\\hline
\end{tabular}
\captionof{table}{Values taken by parameters in Fig. \ref{fig:kc_varies} that are not varied}
\label{tab:LwTsols}
\end{figure}
\end{document}
由于subfigure环境只不过是启用minipage了\caption的，因此可以写成：
\documentclass{article}
\usepackage[demo]{graphicx}
\usepackage[labelformat=simple]{subcaption}
\renewcommand\thesubfigure{(\alph{subfigure})}
\renewcommand\thesubtable{(\alph{subtable})}
\usepackage{array}
\usepackage[all]{xy}
% for \extrasrrowheight
%\usepackage{siunitx}
\begin{document}
\begin{figure}
\centering
%ERC1
\begin{subfigure}[b]{0.4\textwidth}
\[
\xymatrix{
*+[o][F]{C^*} \ar@[d]_{k_{a1}(R-x_1-x_2)} \\
*+[o][F]{x_1 }\ar@[u]_{k_{d1}}
}
\]
\caption{Single binding configuration}
\label{ERC1diagram}
\end{subfigure}
%ERC2
\begin{subfigure}[b]{0.4\textwidth}
\[
\xymatrix{
&*+[o][F]{C^*} \ar@[dl]_{k_{a1}(R-x_1-x_2)} \ar@[dr]^{k_{a2}(R-x_1-x_2)} & \\
*+[o][F]{x_1 }\ar@[ur]_{k_{d1}} & & *+[o][F]{x_2 }\ar@[ul]^{k_{d2}}
}
\]
\caption{Two binding configurations}
\label{ERC2diagram}
\end{subfigure}
\caption[Compartmental diagram of the effective rate constant model]{Compartmental diagram of the ERC model with concentration of analyte at the reaction chip's surface $C^*$, and concentrations of bound analyte $x_1(t)$ and $x_2(t)$.}
\label{ERCdiagram}
\end{figure}
\noindent
\begin{figure}
\centering
\begin{subfigure}[b]{0.45\textwidth}
\includegraphics[width=\textwidth]{ERC_Kd_varies_a2.png}
\caption{Association phase}
\label{Lng1AssPhase}
\end{subfigure}
\begin{subfigure}[b]{0.45\textwidth}
\includegraphics[width=\textwidth]{ERC_Kd_varies_d3.png}
\caption{Dissociation phase}
\label{Lng1AssPhase}
\end{subfigure}\\
\begin{subfigure}[b]{1\textwidth}
\centering
\includegraphics[scale=1.2]{ERC_kd_varies_legend4.png}
\end{subfigure}
\caption{Graphs of bound antibody $x_1$ against time $t$ for the Langmuir single configuration model (green dashed line) and the ERC model for different values of $k_m$.}
%\captionof{figure}{Graphs of bound antibody $x_1$ against time $t$ for the Langmuir single configuration model (green dashed line) and the ERC model for different values of $k_m$.}
\label{fig:kc_varies}
%\end{figure}
%\begin{table}
\vspace{\floatsep}
\centering
\footnotesize
\begin{tabular}
{ | c | c | c | c | c | }
\hline
Parameter &$k_{a}$ & $k_{d}$ & $R$ & $C_T$ \\
&M$^{-1}$s$^{-1}$ &s$^{-1}$& pg nm$^{-2}$ & nM \\\hline
Value &6E-4 &7E-3 & 500 & 100 \\\hline
\end{tabular}
\captionof{table}{Values taken by parameters in Fig. \ref{fig:kc_varies} that are not varied}
\label{tab:LwTsols}
\end{figure}
\end{document}