Depending on the visa type the International Scholars (including post-doctoral researchers), should obtain a Confirmation Letter for High Level Foreign Talents for R Visa, or a Notification Letter of Foreigner’s Work Permit for Z Visa.
For the R Visa holder, applying for the Residence Permit is optional. When deciding not to apply for the Residence Permit, the maximum duration of each stay is 180 days. For the Z Visa holder and the family members holding the S1 Visa, applying for the Residence Permit is mandatory within 30 days after arriving in China.
For more information on the exact procedures and the documents required for application please contact your school or let one of your colleagues assist you. All information can be found on the website of Department of International Affairs.
http://web.sdu.edu.cn/sdgjswb/xnzy1/rjfw1/ywjs.htm