The same papers will not duplicate each other, but the graduation thesis of the same school is hard to say. The earlier you check the duplicate, the more time you will have to revise and improve the paper, so the earlier the better. In general, you can check a copy of your paper once.

Duplicate checking does not mean being included. There are two conditions (1). It must have a power of attorney, which is the author's own power of attorney. (2) Even if it is included in HowNet, it usually takes three months to enter the HowNet database.