Mandelstam Leonid I.

Mandelstam Leonid I. (April 22, 1879 - November 27, 1944) - Soviet physicist, academician. In 1897. enrolled in the Novorossiysk University (Odessa), where in 1798. was expelled for participating in student unrest. Education Graduated in the University of Strasbourg. Since 1918. - Professor of the Odessa Polytechnic Institute, from 1925. - Moscow University. Scientific works of M. relate mainly to the optics, the theory of vibrations and Radiophysics. Studies on optics, mainly devoted to the phenomenon of light scattering. In this paper, 'On the optically homogeneous and turbid media' (1907) M. proven erroneous theory of molecular scattering of light, proposed by British physicist J. Rayleigh, and found that the environment should be heterogeneous, so that it scatters light. Later M. showed that the molecular scattering of monochromatic light must be changed by the wavelength.

Study of the spectral composition of the scattered light has led to the discovery of Mandelstam in 1928. with GS. Landsberg (regardless of ind. Physics B. Ra) Raman. M. owns a number of important works on other issues of physical optics. In the theory of oscillations under the influence of works of M., a new direction, TN. nonlinear oscillation theory, dealing with issues of self-oscillations of excitation and various transformations of oscillation, which has found wide application in various fields of technology, in electronics, automation and t. d. M. conjunction with N.D. Papaleksi opened and examined a number of new phenomena related to the field of nonlinear oscillations. M. and Papaleksi proposed a new method of excitation of electric oscillations - parametric oscillator. In the field of radio physics based on the created by him together with Papaleksi radiointerferentsionnye methods, decided M. (1937) a number of tasks on radiowave propagation over the surface of the earth. They had suggested the possibility of a point measurement of distances using radio waves and with Papaleksi developed radiointerferentsionnye rangefinders are widely used in geodesy and hydrography.

For his work in the field of nonlinear oscillations and the propagation of radio waves and Papaleksi M. (1936) was awarded a prize named after DI. Mendeleev, and in 1942. Stalin Prize. M. also belong to the work on statistical and quantum physics and relativity. Much attention is paid educational activities M.. In 1945, Mr.. USSR Academy of Sciences established two awards named after M. 's for the best work in the field of radio and physics.