Papaleksi, Nikolai Dmitrievich

Born Nov. 20 (Dec. 2), 1880, in Simferopol’; died Feb. 3, 1947, in Moscow. Soviet physicist. Academician of the Academy of Sciences of the USSR (1939; corresponding member, 1931).

After graduating from the University of Strasbourg in 1904, Papaleksi worked there under the direction of C. F. Braun. From 1914 he was a consultant for the Russian Wireless Telegraph and Telephone Company. Papaleksi took part in the organization of the Odessa Polytechnic Institute, which was founded in 1920, and he became a professor there in 1922. From 1923 to 1935, L. I. Mandel’shtam and he directed the scientific section of the Central Radio Laboratory in Leningrad. From 1935 he worked in Moscow at the Institute of Physics of the Academy of Sciences of the USSR and at the academy’s Power Institute. He served as chairman of the All-Union Scientific Council on Radio Physics and Radio Engineering of the Academy of Sciences of the USSR.

Between 1914 and 1916, Papaleksi worked on directional radio telegraphy, experimented with radio communication to submarines and with remote control, and directed the development of the first models of Soviet electron tubes. Together with L. I. Mandel’shtam, Papaleksi carried out fundamental work on nonlinear and parametric oscillations. The two scientists discovered and studied the nth order resonance, combination resonances, and parametric resonances. They developed a method for exciting electrical oscillations parametrically. Using an interference method that they had proposed, they made a detailed study of radio-wave propagation over the surface of the earth and carried out an accurate measurement of the waves’ velocity.

Papaleksi received the D. I. Mendeleev Prize in 1936 and the State Prize of the USSR in 1942. He was awarded the Order of Lenin.