DERYAGIN 84 



G. F. Voroni, the correct breaking up of a space, the geometry 

 of numbers, and mathematical crystallography. Delone present- 

 ed an important method in structural analysis of crystals. He 

 has been concerned with geometrizing the theories of Galois. 

 Bibliography: 



and D. K. Faddeev . Theory on Irrationality of the Third 

 Power. Moscow -Leningrad: 1940. 



and A. D. Aleksandrov. Mathematical Basis in Structural 

 Analysis of Crystals and Determination of the Basic Repeat- 

 ing Parallelepiped with the Use of X-rays. Moscow- 

 Leningrad: 1934. 



Petersburg School of Number Theory. Moscow -Leningrad: 

 1947. 

 Biography: 



On the 60th Anniversary of Boris Nikolaevich Delone. Izvest. 

 Akad. Nauk S.S.S.R., Mat. Ser., 1950, 14, #4. (contains 

 bibliography of the works of Delone). 

 Office: V. A. Steklov Mathematics Institute of USSR 



Academy of Sciences 

 1-y Akademicheskii Proyezd, 28 

 Moscow, USSR 

 Residence: Pyatnitskaya, 12 



Moscow, USSR 

 Telephone: Bl 16 57 



DERYAGIN, BORIS VLADIMIROVICH (Physical Chemist) 



B. V. Deryagin was born August 4, 1902. In 1922 he gradu- 

 ated from Moscow University. He was appointed, in 1935, Chief 

 of the Laboratory of Surface Forces at the Institute of Physical 

 Chemistry of the U.S.S.R. Academy of Sciences. 



Deryagin studied properties of thin layers of liquids. He 

 discovered (together with M. M. Kusakov) the "unwedging 

 action" of these layers. He proposed a theory of coagulation of 

 dispersed systems by electrolytes (1935-41) and the theory of 

 agglomeration of solid particles. He investigated the mecha- 

 nism of lubrication by thin layers and boundaries. He worked 

 out the molecular theory of external friction of solid bodies 

 (1933-34) and (together with N. A. Krotova) the electric theory 

 of adhesion. 



Deryagin became a Corresponding Member of the U.S.S.R. 

 Academy of Sciences in 1946. 



