mod_rewrite caused drop my ranking

I'm owner of http://myisfahan.com. I have an article management system there that developed by myself.

Recently I changed article links from myisfahan.com/articles/isfahan_articleXXX.html to myisfahan.com/XXX_[article subject].html in newer version. Many of my articles had high ranking on Google (in Persian language).

Because I didn't know redirect older links to newer one I only wrote 2 instruction only in the .htaccess:

RewriteRule ^([0-9]+)_([^/\.]+).html$ maghalat.php?id=$1
RewriteRule ^articles/isfahan_articles([0-9]+).html$  maghalat.php?id=$1

After this major change Google.com dropped many of my page rankings and recently I have only 20% of normal site visitors.

My questions are:

1. Does this changes caused this drop of ranking, because in fact now I have 2 links for every content .

2. I fetch subject text by PHP and generate XXX_[article subject].html, how can I write a rewri开发者_如何学运维te syntax that redirect isfahan_articlesXXX.html to XXX_[article subject].html file when XXX is article's ID in .htaccess file?

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You should have 301 redirected your old links to your new links, after creating your new links.

If you did not or are duplicating links to the same content, this would indeed hurt your rankings.

UPDATE

Looks like you already have the RewriteRules in place that you need. Just add the following flags (note the 301 redirect for the old links) and over time it should (over time) rebuild your page rank.

RewriteRule ^([0-9]+)_([^/\.]+).html$ maghalat.php?id=$1 [L]
RewriteRule ^articles/isfahan_articles([0-9]+).html$  maghalat.php?id=$1 [R=301,L]