Unmanned submersible "Hailong III" is put into the sea for a test from the vessel Dayang Yihao (Ocean No. 1), March 24, 2018. The submersible completed a 400-meter-deep sea test in west Pacific Ocean on Saturday. Chinese research vessel Dayang Yihao left Qingdao, Shandong Province, on March 20, taking scientists on a 45-day scientific ocean expedition. (Xinhua/Chen Hao)