Photo taken on May 24, 2019 shows ultra-thin stainless steel strips made by Taiyuan Iron and Steel (Group), or TISCO, in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)