Semyonov, Nikolay Nikolayevich, or Nikolai Nikolaevic Semenov, 1896–1986, Soviet physical chemist, Ph.D. Petrograd Univ., 1917. Semyonov was a professor at the Leningrad Physico-Technical Institute from 1920 to 1931. He then became director of the Institute of Chemical Physics of the USSR Academy of Sciences. In 1944, he joined the faculty at the Moscow State Univ., where he remained until his death. Semyonov was a corecipient of the 1956 Nobel Prize in Chemistry with Sir Cyril Hinshelwood for their research into the mechanism of chemical reactions. Semyonov's work, which focused on chain reactions and the explosiveness displayed during chemical transformations, had a significant influence on the development of more efficient automobile engines as well on jet and rocket engine technology.