On the theory of the structural properties of A-15 type materials

The theory of the structural properties of the A-15 compounds is developed starting with a picture of linear chains of atoms of the transition elements. The twofold-degenerate electronic term is shifted and split when interchain transfer is taken into account. A fine structure of the electronic spectrum and the density of states are examined. The latter has two singularities at the Fermi level corresponding to an estimated variation of the composition by several percent. Among the samples showing the martensitic transformation, one of these singularities is supposed to be responsible for the peculiar properties observed, and a theory of the transformation from the cubic to the tetragonal phase is suggested. The temperature dependence of the phonon spectrum has been studied in detail. The theory explains the softening of the phonon modes at large wave vectors in some directions, and predicts features of the phonon spectrum whose observation could be crucial to the theory.     

Masses of the H,D, He4 and C12 isotopes

Results are given of the measurements of the masses of the H, D, He⁴ and C¹² isotopes carried out by means of a mass-spectrograph with a resolving power of 70,000–100,000. The data obtained agree well with the corresponding mass values obtained from the energy balance of nuclear reactions.The author consider it to be their duty to express their gratitude to M. Ardenne for valuable advice and for his Interest In this work, and also to G. Jaeger, I. A. Chukhtn, attd V. Roggenbuk for the help given by thgm in adjusting the equipment.After the present article was completed a communication by Nier and collaborators [10] appeared giving new preliminary values of masses obtained on a new mass-spectrometer with a maximum resolving power of approximately 100,000: H = 1.0081439 ± 5; D = 2.0147380 ± 10; C¹² = 12.0038174 ± 18.     

Heat Exchange with Horizontal Cylinders in a Centrifugal‐Bubbling Bed

The authors present results of an analysis of experimental data on heat exchange on horizontal cylinders in rotating gasliquid flow. The hydrodynamic parameters of a thin film in a centrifugalbubbling bed have been determined based on the mathematical modeling of a film flow in the case of a highvelocity gasliquid flow about it. Results of a generalization of the data on heat exchange are given, and the hydrodynamic stability criteria for the film flow on the cylinder surface are evaluated.