Defense
| Sat 14 Nov 2026
Beijing, Nov. 14 -- Nanjing Changjiang Waterway Engineering Bureau has secured a patent on Hidden Civil Air Defense Door for Exhibition Hall. Yan Chengdong, Wu Jian, Bai Haipeng, Wang Tangzhong, Wang Hao, Sun Jia, Zhang Peiming, Chen Wenhua, Gao Junqing, Li Gang, Li Lin and Shao Kechen developed the invention.
The patent appl..