Yes, you asked Beijing Institute of Materials. Generally, universities are open to the outside world, but during the epidemic period, schools may require nucleic acid testing to enter. Every university has guards for the safety of students. If anyone can enter the campus at will, then students are not very dangerous at school. Generally speaking, you can enter as long as you explain the situation to the doorman and register your personal information. You can enter the school library and study room, but you should observe discipline on campus and don't do anything illegal. If you contact the school teacher, you can go in. I hope my answer can help you.