Where can i study academic english in an English-speaking country? I am an electrical engineering PhD student, from an African country and the official language here is French, but since most of journals and revues are in English, I always struggle to write my papers and most of them are reject because of the language. I tried to study English in local schools but the result is not so good.

Until a friend of mine suggested that i should try to studying English in an English-speaking country (Preferably the US or the UK), because the interaction with people will also count as practice, So i am looking for a school or training which is specialized in teaching PhD student how to write a scientific paper ? Does a such thing exists in the USA/UK, if yes please point me to them.
I am also non-native English speaker. I also did my Ph.D on social sciences and need to publish articles in English. I first recommend anyone to get online "academic writing" courses. If you search carefully you are going to find that there are Massive Open Online Courses (MOOC) designed specifically for that purpose, i.e. academic English and writing. Price to benefit ratio for such a course will be very high too. If you pay, you will also get a certificate too. 
Writing an article in another language and seeing your mistake in every aspect requires a lot of attention and some time too. You can learn general purpose English, lets say, in a year but improving your writing to a level where even minor mistakes are rare is something not easy to reach. 
Working with editors whose native languages are English can help you to see your mistakes too. 
"Interactions with people" may help you to communicate and perhaps to present your article in a conference though it will not help you to write an article without or with little mistakes. You have to spend a lot of time hanging around, chatting with people just to capture a few "academic words" in a daily life.