A technology explored by my own project, and later found that other companies have applied for patents, can I still send papers?

Generally speaking, no one will bother you after graduation. If you are sure that you have really made something and people are empty shells, you can apply for a patent.

Generally speaking, a patent is a minefield, and 90% of the patents in China are rubbish, just an empty shell waiting for others to step on. If you want to put your technology into industrial application, you can find a special patent application unit to help you avoid patents.