考虑：
\documentclass[12pt,a4paper,oneside]{book}
\usepackage[nottoc]{tocbibind}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{bm}
\usepackage{nccmath}
\usepackage{amsfonts, graphicx, verbatim, mathtools,amssymb, amsthm, mathrsfs,amsmath}
\usepackage{color}
\usepackage{array}
\usepackage{setspace}
\usepackage{fancyhdr}
\usepackage{rsfso}
\usepackage{enumitem}
\usepackage{tikz}
\usetikzlibrary{babel, arrows.meta, positioning, quotes}
\usepackage{parskip}
\usepackage{lipsum}
\usepackage{floatrow}
\usepackage{epstopdf}
\usepackage[capitalise]{cleveref}
\usepackage{siunitx}
\usepackage{tocloft}
\usepackage{listings}
\usepackage{booktabs}
\usepackage{nicematrix}
\usepackage{subcaption}
\usepackage{geometry}
\usepackage{tabularray}
\UseTblrLibrary{booktabs}
\usepackage[thinc]{esdiff}
\usepackage [english]{babel}
\usepackage [autostyle, english = american]{csquotes}
\usepackage[style=numeric,maxbibnames=99,sortcites=true,backend=bibtex]{biblatex}
\allowdisplaybreaks
\begin{document}
\begin{figure} \centering
\begin{tikzpicture}[
node distance = 11mm and 33mm,
N/.style = {draw, minimum size=12mm, inner sep=0pt},
> = {Stealth[scale=0.6]},
every edge/.append style = {draw, ->},
every edge quotes/.append style = {font=\small\linespread{0.75}\selectfont,
inner sep=5pt, sloped}
]
\node [N] (A) {$S$};
\node [N,above right=of A] (B) {$I_1$};
\node [N,below right=of A] (C) {$I_2$};
\node [N,above right=of C] (D) {$J$};
\node [N,right=of D] (E) {$A$};
%
\draw [<-] (A) -- ++(-1,0) node[left] {$\mu$};
\draw [->] (A) -- ++(0,-1) node[below] {$\nu S$};
\draw [->] ([xshift=3.75mm] B.south) -- ++(0,-0.4) node[below] {$\nu I_1$};
\draw [->] (C) -- ++(0,-1) node[below] {$\nu I_2$};
\draw [->] (D) -- ++(0,-1) node[below] {$\nu J$};
\draw [->] ([xshift=-3.5mm] E.south) -- ++(0,-0.4) node[below] {$\alpha A$};
\draw [->] ([xshift=+3.5mm] E.south) -- ++(0,-0.4) node[below] {$\nu A$};
%
\draw ([yshift=+1mm] A.east)
edge [ultra thick, draw=gray,"\slash\slash\slash" anchor=center,
"$\begin{gathered}
p\beta_1 S I_2\\
q\beta_2 S J\\
r\beta_3 S A
\end{gathered}$" ] (B.west)
([yshift=-1mm] A.east)
edge [ultra thick, draw=gray,"\slash\slash\slash" anchor=center,
"$\begin{gathered}
(1-p)\beta_2 S I_2\\
(1-q)\beta_2 S J\\
(1-r)\beta_3 S A
\end{gathered}$" '] (C.west)
(B) edge [rotate=90,"$\epsilon I_1$"] (C)
(D.west) edge ["$\xi_1 J$" ] ( B.east)
( C.east) edge ["$p_1 I_2$" ] (D.west)
([yshift=-2mm] D.west) edge ["$\xi_2 J$" '] ([yshift=-2mm] C.east)
(D) edge ["$p_2 J$"] (E);
\end{tikzpicture}
\setlength{\textfloatsep}{10pt plus 1.0pt minus 2.0pt}
\caption{Flow diagram for the HIV/AIDS model.}
\end{figure}
\end{document}
我怎样才能让这个数字适合边距？我们可以缩放它，也可以将线边从“J”缩小到“A”。我认为后者更好，但我等待您的回复。
答案1
这个解决方案是通用的（我在“必须”使用单位的情况下使用它）：
\documentclass[12pt,a4paper,oneside,showframe]{book}
\usepackage[nottoc]{tocbibind}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{bm}
\usepackage{nccmath}
\usepackage{amsfonts, graphicx, verbatim, mathtools,amssymb, amsthm, mathrsfs,amsmath}
\usepackage{color}
\usepackage{array}
\usepackage{setspace}
\usepackage{fancyhdr}
\usepackage{rsfso}
\usepackage{enumitem}
\usepackage{tikz}
\usetikzlibrary{babel, arrows.meta, positioning, quotes, calc}
\usepackage{parskip}
\usepackage{lipsum}
\usepackage{floatrow}
\usepackage{epstopdf}
\usepackage[capitalise]{cleveref}
\usepackage{siunitx}
\usepackage{tocloft}
\usepackage{listings}
\usepackage{booktabs}
\usepackage{nicematrix}
\usepackage{subcaption}
\usepackage{geometry}
\usepackage{tabularray}
\UseTblrLibrary{booktabs}
\usepackage[thinc]{esdiff}
\usepackage [english]{babel}
\usepackage [autostyle, english = american]{csquotes}
\usepackage[style=numeric,maxbibnames=99,sortcites=true,backend=bibtex]{biblatex}
\allowdisplaybreaks
\begin{document}
\begin{figure} \centering
\def\mscale{0.93}%
\begin{tikzpicture}[
scale=0.9,
node distance = {11*\mscale mm} and {33*\mscale mm},
N/.style = {draw, minimum size={12*\mscale mm}, inner sep=0pt},
> = {Stealth[scale={0.6*\mscale}]},
every edge/.append style = {draw, ->},
every edge quotes/.append style = {font=\small\linespread{0.75}\selectfont,
inner sep={5*\mscale pt}, sloped}
]
\node [N] (A) {$S$};
\node [N,above right=of A] (B) {$I_1$};
\node [N,below right=of A] (C) {$I_2$};
\node [N,above right=of C] (D) {$J$};
\node [N,right=of D] (E) {$A$};
%
\draw [<-] (A) -- ++(-1,0) node[left] {$\mu$};
\draw [->] (A) -- ++(0,-1) node[below] {$\nu S$};
\draw [->] ([xshift={3.75*\mscale mm}] B.south) -- ++(0,-0.4) node[below] {$\nu I_1$};
\draw [->] (C) -- ++(0,-1) node[below] {$\nu I_2$};
\draw [->] (D) -- ++(0,-1) node[below] {$\nu J$};
\draw [->] ([xshift={-3.5*\mscale mm}] E.south) -- ++(0,-0.4) node[below] {$\alpha A$};
\draw [->] ([xshift={3.5*\mscale mm}] E.south) -- ++(0,-0.4) node[below] {$\nu A$};
%
\draw ([yshift={1*\mscale mm}] A.east)
edge [ultra thick, draw=gray,"\slash\slash\slash" anchor=center,
"$\begin{gathered}
p\beta_1 S I_2\\
q\beta_2 S J\\
r\beta_3 S A
\end{gathered}$" ] (B.west)
([yshift={-1*\mscale mm}] A.east)
edge [ultra thick, draw=gray,"\slash\slash\slash" anchor=center,
"$\begin{gathered}
(1-p)\beta_2 S I_2\\
(1-q)\beta_2 S J\\
(1-r)\beta_3 S A
\end{gathered}$" '] (C.west)
(B) edge [rotate=90,"$\epsilon I_1$"] (C)
(D.west) edge ["$\xi_1 J$" ] ( B.east)
( C.east) edge ["$p_1 I_2$" ] (D.west)
([yshift={-2*\mscale mm}] D.west) edge ["$\xi_2 J$" '] ([yshift={-2*\mscale mm}] C.east)
(D) edge ["$p_2 J$"] (E);
\end{tikzpicture}
\setlength{\textfloatsep}{10pt plus 1.0pt minus 2.0pt}
\caption{Flow diagram for the HIV/AIDS model.}
\end{figure}
\end{document}
作为补充（我使用了tikzlibrary calc）
我的方式...将每个维度与定义的\mscale（我的比例）相乘，并将选项添加到的可选参数scale=\mscale中。tikzpicture
在其他情况下，你不必使用单位...不要使用它们...在这种情况下，秤会起作用
额外（font=\mfont为每个节点添加额外命令，以便能够根据需要降低或增加字体大小）
