[HB]

If I publish a paper, can I participate with this work in a conference after paper publication or not

[discodermolide]

Yes, of course you can. You will have to get your presentation or poster submitted to the organisers who will get it refereed. If it's accepted then off you go.

[fledarmus]

You need to be aware of what rights you sign away when you publish your paper in a journal. Although the content of the paper belongs to you (unless it is a work for hire), the exact form it is in may be copyrighted by the publisher of the paper. Simply taking your publication and putting it up on a poster may not qualify as fair use under the copyright laws.

When you present your previously published work in a presentation or poster, present it in a new way, better adapted to the form of presentation or poster. Don't plagiarize, even from yourself.

[orgopete]

If I publish a paper, can I participate with this work in a conference after paper publication or not

I don't know the nature of the conference being considered, but I believe the ACS policy and other chemistry conferences I have attended have a policy that is like this, you can only a paper publish once. If you write a paper, you should only submit it to a single journal.

Before you publish your paper, you can deliver an oral or poster presentation of the paper. This can establish an early publication, or perhaps you can get per-publication feedback (my case). Think of the audience. How would you feel if you attended a conference in which every presenter read their papers from a journal you already read.

This doesn't necessarily limit the publication of already published articles. It is common for major authors to review an entire project referring to their papers as well as other authors in a review format without necessarily introducing any new information.