ปัญหาคือ output ที่ออกมาไม่เป็นภาษาไทยคะ ต้องแก้ไขยังไงคะ

    
    include('C:\AppServ\simple_html_dom.php');
    $urlWithoutProtocol = "http://www.su.ac.th/html_news/news_template.asp?id=5785";
    $request         = "";
    $isRequestHeader = false;
    

    $exHeaderInfoArr   = array();
    $exHeaderInfoArr[] = "Content-type: text/xml";
    $exHeaderInfoArr[] = "Authorization: "."Basic ".base64_encode("authen_user:authen_pwd");
 
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $urlWithoutProtocol);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $request);
    curl_setopt($ch, CURLOPT_HEADER, (($isRequestHeader) ? 1 : 0));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    if( is_array($exHeaderInfo) && !empty($exHeaderInfo) )
    {
        curl_setopt($ch, CURLOPT_HTTPHEADER, $exHeaderInfo);
    }
    $response = curl_exec($ch);
    curl_close($ch);
    $html = str_get_html($response);
    $elem = $html->find('table td.ms09', 0)->plaintext;
    
    $textfile= "test.txt";
    $filew= fopen($textfile, 'w');
    fwrite($filew, $elem);
    fclose($filew);
 
    echo $elem;