我如何表示以下弹簧质量系统

我如何表示以下弹簧质量系统

我该如何表示以下弹簧质量系统?

[弹簧质量系统[1]

答案1

欢迎来到 TeX.SE!我想做广告3D 线圈为了那个原因。

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{decorations.pathmorphing,patterns}
\makeatletter
\newif\ifcoil@closed
\pgfkeys{%
/pgf/decoration/.cd,
3d coil color/.store in=\TDCoilColor, 
3d coil color/.initial=black,
3d coil color=black,
3d coil width/.store in=\TDCoilWidth, 
3d coil width/.initial=0.4pt,
3d coil width=0.4pt,
3d coil dist/.store in=\TDCoilDist, 
3d coil dist/.initial=0.6pt,
3d coil dist=0.6pt,
3d coil opacity/.store in=\TDCoilOpacity, 
3d coil opacity/.initial=1,
3d coil opacity=1,
3d coil closed/.code=\coil@closedtrue
}

 % https://tex.stackexchange.com/a/219088/121799
\tikzset{get stroke color/.code={%
    \expandafter\global% Jump over, now we have \global
    \expandafter\let% Jump over now we have \global\let
    \expandafter\pgfsavedstrokecolor% Jump we have \global\let\pgf...
    \csname\string\color@pgfstrokecolor\endcsname% Finally expand this and put it at the end 
    },                                           % \global\let\pgf...{} in expanded form 
    restore stroke color/.code={\pgf@setstrokecolor#1},
}
\def\pgfpoint@onthreedcoil#1#2#3{%
  \pgf@x=#1\pgfdecorationsegmentamplitude%
  \pgf@x=\pgfdecorationsegmentaspect\pgf@x%
  \pgf@y=#2\pgfdecorationsegmentamplitude%
  \pgf@xa=0.083333333333\pgfdecorationsegmentlength%
  \advance\pgf@x by#3\pgf@xa%
  \advance\pgf@x by-\generaloffset pt%
}

% coil decoration
%
% Parameters: \pgfdecorationsegmentamplitude, \pgfdecorationsegmentlength,

\pgfdeclaredecoration{3d complete coil}{initial}
{ 
    \state{initial}[width=0.5*\pgfdecorationsegmentlength,
    next state=coil, persistent precomputation={% from https://tex.stackexchange.com/a/25689/121799
    \pgfmathsetmacro\matchinglength{\pgfdecoratedinputsegmentlength / int(\pgfdecoratedinputsegmentlength/\pgfdecorationsegmentlength)}
    \setlength{\pgfdecorationsegmentlength}{\matchinglength pt}
    \tikzset{get stroke color}
    \pgfmathsetmacro{\generaloffset}{\pgfdecorationsegmentlength}
    \pgfmathsetmacro{\initialoffset}{1.5*\pgfdecorationsegmentlength}
    \pgfmathsetmacro{\auxoffset}{2.5*\pgfdecorationsegmentlength}
  }]    { 
    % line in the back
    %
    \pgfsetstrokecolor{\TDCoilColor}
    \pgfsetfillcolor{\TDCoilColor}
    \pgfsetstrokeopacity{\TDCoilOpacity}
    \pgfsetlinewidth{\TDCoilWidth}     
    \ifcoil@closed
     \begingroup
      \def\generaloffset{\auxoffset}
      \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
      \pgfpathcurveto
      {\pgfpoint@onthreedcoil{1.555}{ 1    }{16}}
      {\pgfpoint@onthreedcoil{2    }{ 0.555}{17}}
      {\pgfpoint@onthreedcoil{2    }{ 0    }{18}}
      \pgfcoordinate{TD@coilast}{\pgfpoint@onthreedcoil{2    }{ 0    }{18}}
      \pgfcoordinate{TD@coilfirst}{\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
      \pgfusepath{stroke} 
      \pgfsetstrokecolor{\TDCoilColor}
     \endgroup
    \fi
    \begingroup %
    \def\generaloffset{\initialoffset}
    \ifcoil@closed
     \pgfpathmoveto{\pgfpointanchor{TD@coilast}{center}}
    \else
     \pgfpathmoveto{\pgfpointorigin}
    \fi
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{2    }{-0.555}{7}}
    {\pgfpoint@onthreedcoil{1.555}{-1    }{8}}
    {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfusepath{stroke} 
    %
    % white background for front thick part
    %
    \pgfsetstrokeopacity{1}
    \pgfsetstrokecolor{white}
    \pgfsetfillcolor{white}
    \pgfsetlinewidth{1.5*\TDCoilWidth+1.5*\TDCoilDist}
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    % draw forward
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
    {\pgfpoint@onthreedcoil{0    }{-0.555}{11.25}}
    {\pgfpoint@onthreedcoil{0    }{ 0    }{12.5}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0    }{ 0.555}{13.25}}
    {\pgfpoint@onthreedcoil{0.445}{ 1    }{14.25}}
    {\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
    % draw the curve back
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0.445}{ 1    }{14}}
    {\pgfpoint@onthreedcoil{0    }{ 0.555}{12.75}}
    {\pgfpoint@onthreedcoil{0    }{ 0    }{11.5}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0    }{-0.555}{10.75}}
    {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
    {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfusepath{stroke,fill} 
    % 
    % draw the thick foreground path
    %
    \pgfsetstrokecolor{\TDCoilColor}
    \pgfsetfillcolor{\TDCoilColor}
    \pgfsetstrokeopacity{\TDCoilOpacity}
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{3}}
    \pgfsetlinewidth{\TDCoilWidth} 
    % forward shifted +
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
    {\pgfpoint@onthreedcoil{0    }{-0.555}{11.25}}
    {\pgfpoint@onthreedcoil{0    }{ 0    }{12.5}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0    }{ 0.555}{13.25}}
    {\pgfpoint@onthreedcoil{0.445}{ 1    }{14.25}}
    {\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
    % draw the curve back shfted -
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0.445}{ 1    }{14}}
    {\pgfpoint@onthreedcoil{0    }{ 0.555}{12.75}}
    {\pgfpoint@onthreedcoil{0    }{ 0    }{11.5}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0    }{-0.555}{10.75}}
    {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
    {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfusepath{stroke,fill} 
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{1.555}{ 1    }{16}}
    {\pgfpoint@onthreedcoil{2    }{ 0.555}{17}}
    {\pgfpoint@onthreedcoil{2    }{ 0    }{18}}
    \pgfcoordinate{TD@coilast}{\pgfpoint@onthreedcoil{2    }{ 0    }{18}} 
    \pgfusepath{stroke}     
    \endgroup
  }
  \state{coil}[switch if less than=%
    1.9*\pgfdecorationsegmentlength  to last,
               width=+\pgfdecorationsegmentlength]
    { % line in the back
    %
    \pgfsetstrokecolor{\TDCoilColor}
    \pgfsetfillcolor{\TDCoilColor}
    \pgfsetstrokeopacity{\TDCoilOpacity}
    \pgfpathmoveto{\pgfpointanchor{TD@coilast}{center}}
    \pgfsetlinewidth{\TDCoilWidth} 
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{2    }{-0.555}{7}}
    {\pgfpoint@onthreedcoil{1.555}{-1    }{8}}
    {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfusepath{stroke} 
    %
    % white background for front thick part
    %
    \pgfsetstrokeopacity{1}
    \pgfsetstrokecolor{white}
    \pgfsetfillcolor{white}
    \pgfsetlinewidth{1.5*\TDCoilWidth+1.5*\TDCoilDist}
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{3}}
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    % draw forward
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
    {\pgfpoint@onthreedcoil{0    }{-0.555}{11.25}}
    {\pgfpoint@onthreedcoil{0    }{ 0    }{12.5}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0    }{ 0.555}{13.25}}
    {\pgfpoint@onthreedcoil{0.445}{ 1    }{14.25}}
    {\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
    % draw the curve back
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0.445}{ 1    }{14}}
    {\pgfpoint@onthreedcoil{0    }{ 0.555}{12.75}}
    {\pgfpoint@onthreedcoil{0    }{ 0    }{11.5}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0    }{-0.555}{10.75}}
    {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
    {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfusepath{stroke,fill} 
    % 
    % draw the thick foreground path
    %
    \pgfsetstrokecolor{\TDCoilColor}
    \pgfsetfillcolor{\TDCoilColor}
    \pgfsetstrokeopacity{\TDCoilOpacity}
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{3}}
    \pgfsetlinewidth{\TDCoilWidth} 
    % forward shifted +
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
    {\pgfpoint@onthreedcoil{0    }{-0.555}{11.25}}
    {\pgfpoint@onthreedcoil{0    }{ 0    }{12.5}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0    }{ 0.555}{13.25}}
    {\pgfpoint@onthreedcoil{0.445}{ 1    }{14.25}}
    {\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
    % draw the curve back shfted -
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0.445}{ 1    }{14}}
    {\pgfpoint@onthreedcoil{0    }{ 0.555}{12.75}}
    {\pgfpoint@onthreedcoil{0    }{ 0    }{11.5}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{0    }{-0.555}{10.75}}
    {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
    {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfusepath{stroke,fill} 
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{1.555}{ 1    }{16}}
    {\pgfpoint@onthreedcoil{2    }{ 0.555}{17}}
    {\pgfpoint@onthreedcoil{2    }{ 0    }{18}}
    \pgfusepath{stroke} 
    \pgfcoordinate{TD@coilast}{\pgfpoint@onthreedcoil{2    }{ 0    }{18}} 
  }
  \state{last}[next state=final]
    { % line in the back
    %
    \pgfsetstrokecolor{\TDCoilColor}
    \pgfsetfillcolor{\TDCoilColor}
    \pgfsetstrokeopacity{\TDCoilOpacity}
    \pgfpathmoveto{\pgfpointanchor{TD@coilast}{center}}
    \pgfsetlinewidth{\TDCoilWidth} 
    \pgfpathcurveto
    {\pgfpoint@onthreedcoil{2    }{-0.555}{7}}
    {\pgfpoint@onthreedcoil{1.555}{-1    }{8}}
    {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
    \pgfusepath{stroke} 
    % 
    % draw the thick foreground path
    %
    \ifcoil@closed %\pgfpointanchor{TD@coilfirst}{center}
     %
     % white background for front thick part
     %
     \pgfsetstrokeopacity{1}
     \pgfsetstrokecolor{white}
     \pgfsetfillcolor{white}
     \pgfsetlinewidth{1.5*\TDCoilWidth+1.5*\TDCoilDist}
     \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{3}}
     \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{-1    }{9}}
     % draw forward
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
     {\pgfpoint@onthreedcoil{0    }{-0.555}{11.25}}
     {\pgfpoint@onthreedcoil{0    }{ 0    }{12.5}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0    }{ 0.555}{13.25}}
     {\pgfpoint@onthreedcoil{0.445}{ 1    }{14.25}}
     {\pgfpointanchor{TD@coilfirst}{center}}
     % draw the curve back
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0.445}{ 1    }{14}}
     {\pgfpoint@onthreedcoil{0    }{ 0.555}{12.75}}
     {\pgfpoint@onthreedcoil{0    }{ 0    }{11.5}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0    }{-0.555}{10.75}}
     {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
     {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
     \pgfusepath{stroke,fill} 
     \pgfsetstrokecolor{\TDCoilColor}
     \pgfsetfillcolor{\TDCoilColor}
     \pgfsetstrokeopacity{\TDCoilOpacity}
     \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{3}}
     \pgfsetlinewidth{\TDCoilWidth} 
     % forward shifted +
     \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{-1    }{9}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
     {\pgfpoint@onthreedcoil{0    }{-0.555}{11.25}}
     {\pgfpoint@onthreedcoil{0    }{ 0    }{12.5}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0    }{ 0.555}{13.25}}
     {\pgfpoint@onthreedcoil{0.445}{ 1    }{14.25}}
     {\pgfpointanchor{TD@coilfirst}{center}}
     % draw the curve back shifted 
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0.445}{ 1    }{14}}
     {\pgfpoint@onthreedcoil{0    }{ 0.555}{12.75}}
     {\pgfpoint@onthreedcoil{0    }{ 0    }{11.5}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0    }{-0.555}{10.75}}
     {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
     {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
     \pgfusepath{stroke,fill} 
    \else
     %
     % white background for front thick part
     %
     \pgfsetstrokeopacity{1}
     \pgfsetstrokecolor{white}
     \pgfsetfillcolor{white}
     \pgfsetlinewidth{1.5*\TDCoilWidth+1.5*\TDCoilDist}
     \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{3}}
     \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{-1    }{9}}
     % draw forward
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
     {\pgfpoint@onthreedcoil{0    }{-0.555}{11.25}}
     {\pgfpoint@onthreedcoil{0    }{ 0    }{12.5}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0    }{ 0.555}{13.25}}
     {\pgfpoint@onthreedcoil{0.445}{ 1    }{14.25}}
     {\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
     % draw the curve back
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0.445}{ 1    }{14}}
     {\pgfpoint@onthreedcoil{0    }{ 0.555}{12.75}}
     {\pgfpoint@onthreedcoil{0    }{ 0    }{11.5}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0    }{-0.555}{10.75}}
     {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
     {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
     \pgfusepath{stroke,fill} 
     \pgfsetstrokecolor{\TDCoilColor}
     \pgfsetfillcolor{\TDCoilColor}
     \pgfsetstrokeopacity{\TDCoilOpacity}
     \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{3}}
     \pgfsetlinewidth{\TDCoilWidth} 
     % forward shifted +
     \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{-1    }{9}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
     {\pgfpoint@onthreedcoil{0    }{-0.555}{11.25}}
     {\pgfpoint@onthreedcoil{0    }{ 0    }{12.5}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0    }{ 0.555}{13.25}}
     {\pgfpoint@onthreedcoil{0.445}{ 1    }{14.25}}
     {\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
     % draw the curve back shifted 
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0.445}{ 1    }{14}}
     {\pgfpoint@onthreedcoil{0    }{ 0.555}{12.75}}
     {\pgfpoint@onthreedcoil{0    }{ 0    }{11.5}}
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{0    }{-0.555}{10.75}}
     {\pgfpoint@onthreedcoil{0.445}{-1    }{10}}
     {\pgfpoint@onthreedcoil{1    }{-1    }{9}}
     \pgfusepath{stroke,fill} 
    \fi
    \pgfpathmoveto{\pgfpoint@onthreedcoil{1    }{ 1    }{15}}
    \ifcoil@closed %TD@coilfirst
    \else
     \pgfpathcurveto
     {\pgfpoint@onthreedcoil{1.555}{ 1    }{16}}
     {\pgfpoint@onthreedcoil{2    }{ 0.555}{17}}
     {\pgfpoint@onthreedcoil{2    }{ 0    }{18}}
    \fi
    \pgfusepath{stroke} 
    %\pgfcoordinate{TD@coilast}{\pgfpoint@onthreedcoil{2    }{ 0    }{18}} 
  }
  \state{final}
  {
    \pgfpathmoveto{\pgfpointdecoratedpathlast}
    \tikzset{restore stroke color/.expand once=\pgfsavedstrokecolor}
  }
}
\makeatother

\begin{document}
\begin{tikzpicture}[decoration={3d coil color=black,aspect=0.35, segment length=3mm, 
amplitude=3mm,3d complete  coil},thick,font=\sffamily]
% left
\fill[pattern=north east lines] (-1,7) rectangle (1,7.5);
\draw[very thick] (-1,7) -- (1,7);
\node[anchor=south] at (0,7.5) {Equilibrium};
\draw (0,4) -- (0,5) coordinate[midway](m1);
\draw (0,1) -- (0,0.5) coordinate(m2);
\fill (m1) circle (2pt) node[left] {$m_1$};
\fill (m2) circle (2pt) node[left] {$m_2$};
\draw[decorate,segment length=2mm] (0,5) -- (0,7);
\draw[decorate,segment length=3mm] (0,1) -- (0,4.1);
% right
\fill[pattern=north east lines] (2,7) rectangle (4,7.5);
\draw[very thick] (2,7) -- (4,7);
\node[anchor=south] at (3,7.5) {Motion};
\draw (3,3) -- (3,4) coordinate[midway](m1');
\draw (3,0) -- (3,-0.5) coordinate(m2');
\fill (m1') circle (2pt) (m2') circle (2pt);
\draw[decorate,segment length=3mm] (3,4) -- (3,7);
\draw[decorate,segment length=3mm] (3,0) -- (3,3);
% middle
\draw[dashed] (m1) -- (2.8,0 |- m1) coordinate[pos=0.9] (x1top);
\draw[-latex] (x1top) -- (x1top |-m1') node[left]{$x_1$};
\draw[dashed] (m2) -- (2.8,0 |- m2) coordinate[pos=0.9] (x2top);
\draw[-latex] (x2top) -- (x2top |-m2') node[left]{$x_2$};
\end{tikzpicture}
\end{document}

在此处输入图片描述

答案2

受@marmot 回答启发而来的一个不太复杂的解决方案:

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{decorations.pathmorphing,patterns}

\tikzset{
 spring/.style={very thick,
    decorate,
    decoration={coil,
      amplitude=1.5mm,
      segment length=2mm,
      pre length=3mm,
      post length=3mm,
      aspect=0.6,
    }},
  %
  equilibrium state/.style={spring},
  %
  motion state/.style={spring,/pgf/decoration/segment length=2.5mm},
 %
  ground/.style={pattern=north east lines},
}

\begin{document}
\begin{tikzpicture}
% left

\fill[ground] (-1,7) rectangle (1,7.5);
\draw[very thick] (-1,7) -- (1,7);
\node[anchor=south] at (0,7.5) {Equilibrium};

\draw[ equilibrium state] (0,4)coordinate(m1) -- (0,7);
\draw[ equilibrium state] (0,1)coordinate(m2) -- (m1);
\fill (m1) circle (2pt) node[left] {$m_1$};
\fill (m2) circle (2pt) node[left] {$m_2$};
% right
\fill[ground] (2,7) rectangle (4,7.5);
\draw[very thick] (2,7) -- (4,7);
\node[anchor=south] at (3,7.5) {Motion};
\draw[ motion state] (3,3.5)coordinate(m'1) -- (3,7);
\draw[ motion state] (3,0)coordinate(m'2) -- (m'1);
\fill (m'1) circle (2pt) node[right] {$m_1$};
\fill (m'2) circle (2pt) node[right] {$m_2$};


% middle
\draw[dashed] (m1) -- (2.8,0 |- m1) coordinate[pos=0.9] (x1top);
\draw[-latex] (x1top) -- (x1top |-m'1) node[left]{$x_1$};
\draw[dashed] (m2) -- (2.8,0 |- m2) coordinate[pos=0.9] (x2top);
\draw[-latex] (x2top) -- (x2top |-m'2) node[left]{$x_2$};
\end{tikzpicture}
\end{document}

在此处输入图片描述

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