updated article figure

Author: simongravelle

docs/sphinx/source/tutorials/figures/level1/breaking-a-carbon-nanotube/length-unbreakable-article.png

@@ -111,7 +111,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 8,
+   "execution_count": 9,
    "id": "6154342b",
    "metadata": {},
    "outputs": [
@@ -127,7 +127,7 @@
     }
    ],
    "source": [
-    "filename = \"stress-strain-unbreakable-article\"\n",
+    "filename = \"length-unbreakable-article\"\n",
     "dark_mode = False\n",
     "\n",
     "# Initialise figure\n",