Korean Characters Not Working simplexml_load_file

well currently I'm loading the youtube rss feed using

simplexml_load_file

The problem I've run into is that it's not returning anything when I use korean characters in the url. The youtube url works just fine if you type it in the browser, but if you run it through the function nothing.

and example url is

http://gdata.youtube.com/feeds/api/videos?q=%EB%开发者_开发知识库95%8C%EB%B6%80%ED%84%B0&orderby=viewCount&start-index=1&max-results=10

loads just fine if you put it in your browser but simplexml_load_file returns nothing.

Thanks