Chinese scientists who conducted the country's first round-the-world scientific research cruise aboard the research vessel "Dayang No. One" returned to Qingdao, the departure city, on Sunday.

In a congratulatory letter, Vice Premier Zeng Peiyan called on the Chinese oceangraphers to learn more about the benthal world, develop oceanic science and technology and train more oceanic professionals.

The scientists set off on April 2, 2005, and visited the Pacific Ocean, the Atlantic Ocean and the Indian Ocean.