string(247) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%94%B5%E6%B0%B8%E7%A3%81%E9%93%81%E5%B7%A5%E4%BD%9C%E5%8E%9F%E7%90%86%E5%9B%BE => Failed to connect to 14.18.117.71 port 38041: Connection refused"
电永磁铁工作原理图
