2. The author of the thesis topic does not meet the requirements.
3. The number of thesis topics does not meet the requirements.
4. The title retrieval of the paper does not meet the requirements.
5. Magazines published with professional names do not meet the requirements.
6. The publication time of the thesis topic does not meet the requirements.
I. Analysis of possible causes
1, which means that the brake system lacks necessary maintenance, there are too many impurities in the bra