How to specify encoding?

Question

PHP

There is this code:

$strTmpOff.= 
"<g:description>".
yandex_text2xml(TruncateText(
($arAcc["PREVIEW_TEXT_TYPE"]=="html"? 
strip_tags(preg_replace_callback("'&[^;]*;'", "replace_special", 
$arAcc["~PREVIEW_TEXT"])) : $arAcc["PREVIEW_TEXT"].'Товар
 сертифицирован. Доставка по всей России.'),
3000), true).
"</g:description>\n";

I need to add utf-8 indication to the top code as in the code below:

$strTmpOff.= "<g:title>".htmlspecialchars($APPLICATION->
ConvertCharset($arAcc[NAME], LANG_CHARSET, 'utf-8'))."</g:title>\n";

Apparently I'm adding it incorrectly, since errors appear during the formation of the feed.