not able to 301 redirect url in drupal

i am trying to redirect an url from location a to b using .htaccess with the following code

RewriteRule ^accessibility$ http://example.com/topic/accessibility/ [R=301,L] 

it is not working

i have this turned on

RewriteCond %{HTTP_HOST} ^www\.(.+)开发者_如何学运维$ [NC]
   RewriteRule ^ http://%1%{REQUEST_URI} [L,R=301]

I think you're right: that won't work. Use the Path redirect module instead. Here is an excerpt from its project page:

... allows you to specify a redirect from one path to another path or an external URL, using any HTTP redirect status.

Try:

RewriteCond %{REQUEST_URI} ^/accessibility$ [NC]
RewriteRule ^(.*)$ http://example.com/topic/$1 [L,R=301]

BTW, mod_rewrite related questions are better asked on serverfault.com, so don't be surprised if a moderator migrates this question over there.