devoted himself to research in engineering structural mechanics. He made important contributions in variation principles to limit analysis, computational mechanics and structural optimization. In 1950, Qian published his influential paper "Theory of Complementary Energy" in the journal Science in China. It led his student Hu Haichang to derive the Hu–Washizu principle in 1954. In the early 1960s, Qian and his student Zhong Wanxie published two papers in Science in China and Acta Mechanica Sinica, on the "general variational theory of limit analysis and plasticity". Their research was used in submarine design and was awarded national prizes. In the 1970s, Qian designed the main part of China's first modern petroleum port in Dalian, Liaoning. In the early 1980s, Qian, together with Zhong Wanxie and Cheng Gengdong, developed DDDU, an advanced computer system for structural design. DDDU was used in many major engineering projects. Education In 1951, Qian wrote two structural mechanics textbooks, which were widely used in Chinese universities and educated a generation of Chinese civil engineers. Qian is celebrated in China as a "Bo Le" for scientists. Six of his former students have become academicians: Pan Jiazheng, Hu Haichang, Cheng Gengdong, Zhong Wanxie, Qiu Dahong, and Yang Jinzong. Pan Jiazheng, who was Qian's student at Zhejiang University, almost dropped out of college because of poverty. When Qian learned about his situation, he paid for Pan's tuition and living expenses out of his own pocket until his graduation. Pan would later become one of the chief engineers of the Three Gorges Dam. Major publications [1] Qian Lingxi, , China Science Book and Instrument Company, Shanghai, 1951. [2] Qian Lingxi, , China Science Book Instrument Company, Shanghai, 1952. [3] Б. Н. Жемочкин, , Translated by Qian Lingxi. Transportation Ministry of Inland Waterway Technology Research Group, 1953. [4] Э. Ф. Gorhuangwei, Т. В. Ender. , Translated by Qian Lingxi and Gao Guofan. People's Communications Press, Beijing, 1955. [5] (Based on the lecture notes prepared by Qian Lingxi) Compiled by the General Administration of Navigation Engineering, Ministry of Communications of the People's Republic of China, Port Building, Vol 1, , People's Communications Publishing House, Beijing, 1955. [6] Н. Х. Arugiu Nieyang, , Translated by Wu Ruifeng, Lu Kuangzhou, Fang Xiaoshu, Zhao Deyong, Qian Lingxi, etc., Beijing Science Press, Beijing, 1961. [7] Qian Lingxi and Zhong Wanxie, , The Science and Technology Commission of the Republic of China, Beijing, 1964. [8] Qian Lingxi, editor in