[jQuery] Correct me!

Hi!
I have used following things in separate JS file so no conflict
will be there between JQUERY and other JS frameworks.
a-
var dom = {};
dom.query = jQuery.noConflict(true);
b-
var jQ = jQuery.noConflict();
c-
jQuery.noConflict();
But when I used jQ or others, FireBug gives error.
But in usage of $ , there is no problem and all works fine.
Can someone solve my problem.
Thanks in advance