Dynamics of the two-SBT-memristor-based chaotic circuit*Project supported by the National Natural Science Foundation of China (Grant Nos. 61703247 and 61703246), the Qingdao Science and Technology Plan Project, China (Grant No. 19-6-2-2-cg), the Elite Project of Shandong University of Science and Technology, and the Taishan Scholar Project of Shandong Province of China. (November 2020)