Figures TIKZ du cours "Diffusion moléculaire"

              
% !TEX encoding = UTF-8 Unicode
% J.Roussel
% Ce document regroupe les codes TIKZ des figures utilisées pour le cours "Diffusion de particules" situé à la page http://femto-physique.fr/physique_statistique/phystat_C4.php


\documentclass[11pt]{article}
\input{styles_phystat}
\title{Figures TIKZ du cours "Diffusion moléculaire"}
\begin{document}

%--- flux du vecteur vitesse
	\begin{tikzpicture} [decoration={markings,mark=at position 1cm with {\arrow[]{stealth};}}]
	\draw[fill=gray](0,0)node{$\bullet$}node[above=5pt]{M}ellipse(0.5 and 1)++(0,-1)node[below]{d$S$};
	\draw[<-, shift={(-0.07,1)}](0,0)--++(2,1)node[above,midway]{$\overrightarrow{v}\,\mathrm{d}t$};
	\draw[<-, shift={(+0.07,-1)}](0,0)--++(2,1);
	\draw[dashed](2,1)ellipse(0.5 and 1);
	\draw[gray, <-, shift={(+0.5,0)}](0,0)--++(2,1);
	\draw[gray, <-, shift={(+0.43,0.5)}](0,0)--++(2,1);
	\draw[gray, <-, shift={(+0.43,-0.5)}](0,0)--++(2,1);
	\draw[->](0,0)--++(-1.6,-0.8)node[below]{$\overrightarrow{v}(\mathrm{M},t)$};
	\draw[vecteur,->](0,0)--++(-1,-0.1)node[above=3pt]{$\overrightarrow{\mathrm{d}S}$};
	\draw(-0.8,-0.08) to[bend right](-0.8,-0.4);
	\draw(-1.1,-0.3)node{\small $\theta$};
	\end{tikzpicture}
	
	
% --- tube de courant
	\begin{tikzpicture} [scale=1.3,decoration={markings,mark=at position 3cm with {\arrow[]{stealth};}}]
		\draw[red,postaction={decorate}](0,0.5)--++(5,0)node[black,midway,above,sloped]{\small Tube de courant};
		\draw[red,postaction={decorate}](0,-0.5)--++(5,0);
		\draw[fill=red,opacity=0.5](5,0) ellipse(0.3 and 0.5);
		\draw (5,0)node[below]{$(S)$};
		\draw[red,dashed,->](0,0)--++(6,0)node[right]{$\overrightarrow{u_x}$};
		\draw[fill=lightgray,opacity=0.8](0.4,0) ellipse(0.3 and 0.5);
		\draw (0.4,-0.5)node[below=5pt]{$(x)$};
		\draw[shift={(3,0)},fill=lightgray,opacity=0.8](0.4,0) ellipse(0.3 and 0.5);
		\draw (3.4,-0.5)node[below=5pt]{$(x+\mathrm{d}x)$};
		\draw[vecteur](0.4,0)node{$\bullet$}--++(1,0)node[above]{\small $\overrightarrow{\jmath_n}(x,t)$};
		\draw[vecteur](3.4,0)node{$\bullet$}--++(1,0)node[above]{\small $\overrightarrow{\jmath_n}(x+\mathrm{d}x,t)$};
	\end{tikzpicture}
	


% --- Paramètre d'impact.
	\begin{tikzpicture} [scale=1] 
		\draw[dashed,shift={(-2,-1)}](0,0)--++(4,2);
		\draw[dashed,shift={(-3,-1.5)}](0.5,2)--++(4,2);
		\draw[doublefleche,shift={(-0.8,-0.4)}](0,0)--++(-0.7,1.4) node[midway, left]{$b$};
		\draw[vecteur] (0,0)--++(1,0.5)node[below right]{$\overrightarrow{v}_{\rm A/B}$};
		\draw[vecteur] (0.5,2)--++(-1,-0.5)node[below right]{$\overrightarrow{v}_{\rm B/A}$};
		\draw[thin,ball color=white] (0,0) circle(2ex)node{A};
		\draw[thin,ball color=white] (0.5,2) circle(2ex)node{B};
	\end{tikzpicture}
	

% ---Marche aléatoire d'une molécule dans un gaz
\begin{tikzpicture} [scale=0.7] 
	\draw[thin,double distance=4ex,draw=lightgray,double=blue!20!white] (0,0)--++(1,2)--++(-4,-2)--++(0,-3)--++(4,0)--++(4,3);
	\draw (0,0)--++(1,2)--++(-4,-2)--++(0,-3)--++(4,0)--++(4,3);
	\draw[vecteur] (0,0)--++(0.5,1);
	\draw[thin,ball color=white] (0,0) circle(1ex);
	\draw[shift={(-2ex,1ex)}](0,0)--++(4ex,-2ex)node[right]{section $\sigma$};
\end{tikzpicture}


% --- Marche aléatoire discrète sur réseau carré.
\begin{tikzpicture} [scale=0.78] 
		\draw[help lines] (-4,-3) grid (4,3);
		\draw[double=white] (0,0)--++(1,0)--++(1,0)--++(0,1)--++(-1,0)--++(0,-1)--++(0,-1)--++(-1,0)--++(-1,0)--++(0,-1)--++(1,0)--++(1,0)--++(1,0)--++(0,1)--++(1,0)--++(0,-1); 
		\draw[<->](-3,-2)--++(1,0) node[midway,above]{$\ell$};
		\draw (0,0) node{•};
		\draw (3,-2) node{•};
		\draw[force](0,0)--(3,-2)node[midway,below]{$\overrightarrow{R}_N$};
\end{tikzpicture}

\end{document}