The specific time for Nanjing University of Science and Technology to select class cadres may vary from college to college and from grade to grade. Generally speaking, the time for selecting class cadres will be before the start of the new semester, so that the new class can have suitable organization and leadership. Elections are usually held within one to two weeks after the start of the new semester.

Specific election procedures and time arrangements can be carried out under the guidance of the school class teacher. The school will issue a notice on the selection of class cadres, and the class will organize elections within the specified time, and run for the positions of person in charge or class representative, study Committee member, life Committee member and so on. There is usually a certain amount of time to prepare for the election, vote and announce the election results.

Please note that the above answers are based on normal experience and understanding, and the specific arrangements may be adjusted due to school policies, school calendar arrangements and other factors. It is recommended that you consult the official announcement of Nanjing University of Science and Technology or the relevant person in charge of the school to obtain the most accurate information.