並前往https://www.studocu.com/tw/document/national-tsing-hua-university/mechanics-of-materials/magnetic-fields-of-helmholtz-coil-%E4%BA%A5%E5%A7%86%E9%9C%8D%E8%8C%B2%E7%B7%9A%E5%9C%88%E7%A3%81%E5%A0%B4/4112366