curl_init回来的编码怎么判断？个别文字乱码求解！

<?php$url = "http://zhidao.baidu.com/link?url=pTwcJotQ02pjg-mjCnc-fkw8ONOY9x8q0ESrCFhdVJy47agZnDnCb-BCAtngRGDt9yi0TvleSS_w0aPj8Vsk0atVkVhNYdZADN0kv0BzNau";echo fopen_url($url);function fopen_url($url) {     if (function_exists('curl_init'))	{         $curl_handle = curl_init();         curl_setopt($curl_handle, CURLOPT_URL, $url);         curl_setopt($curl_handle, CURLOPT_CONNECTTIMEOUT,2);         curl_setopt($curl_handle, CURLOPT_RETURNTRANSFER,1);         curl_setopt($curl_handle, CURLOPT_FAILONERROR,1); 		curl_setopt($curl_handle, CURLOPT_TIMEOUT,2);        $file_content = curl_exec($curl_handle);		$encode = mb_detect_encoding($file_content, array("ASCII","UTF-8","GB2312","GBK","BIG5"));				if($encode != "UTF-8")		{		   $file_content = mb_convert_encoding($file_content, "UTF-8", $encode);		   //$file_content = iconv($encode,'utf-8//IGNORE',$file_content);		}        curl_close($curl_handle);     }	else	{         $file_content = '';     }     return $file_content; }?>