Diffusion in binary gas mixtures studied by NMR of hyperpolarized gases and molecular dynamics simulations.

The dependence of the individual mean square displacement of rare gases in binary mixtures is studied by a combined experimental and theoretical approach. We show that the diffusion constant can be varied in a considerable range by changing the molar fractions of the mixtures. On the experimental side, NMR diffusion measurements are done on hyperpolarized 3He and 129Xe, mixed with several inert buffer gases, in the presence of a magnetic field gradient. The results are compared to diffusion coefficients obtained from atomistic molecular dynamics simulations based on Lennard-Jones type potentials of the corresponding gas mixtures, and to appropriate analytical expressions, yielding very good mutual agreement. This study is the first quantitative validation of the effects of the mutual interactions between gas particles on the individual diffusion properties. It is shown that the dependency of gas phase diffusion properties on the local chemical environment may not be neglected, e.g. in diffusion-controlled chemical reactions.

[Physiologic and hygienic characteristics of college teachers work].

First series of studies covered analysis of lecture with registering number of words and movements complementary to them. The series 2 determined occupational activities of college teacher, according to contemporary hygienic classification, as highly intensive work requiring physiologic and managerial correction.

[Sensomotory performance with arbitrary and fixed rhythm of hand movements]. / Sensomotornaia rabotosposobnost' s proizvol'nym i zadannym ritmom dvizheniia ruki.

Experimental study covered females of three age groups and revealed variation differences in time of arbitrary rhythmichand movements (tapping-test) and of movents with fixed rhythm of response to light. Their difference is represented as additional time for associations between cortical centers in regulation of hand movements.