Quantum-dynamical study in three-dimensional space of the exchange reaction H+ClH'→HCl+H' with zero total angular momentum $ \left( {\overrightarrow J = 0} \right) $

The 3D quantum dynamics of the exchange reaction H + ClH′→HCl+H′ with zero angular momentum was studied. The nonstationary Schr?dinger equation was solved by expansion into a basis set using discrete variable representation. The probabilities of the reaction were determined in relation to the total energy for the ground and first excited vibrational states.     

Low-temperature ferromagnetic resonance in epitaxial garnet films on paramagnetic substrates

The temperature dependence (4.2–300 K) of ferromagnetic resonance (FMR) in the 3-cm range in films of yttrium-iron garnet (YIG)1.7–3 m thick, epitaxially grown on a paramagnetic gadolinium-gallium garnet (GGG) paramagnetic substrate is studied. It is found that with decrease in temperature, beginning at T 70 K, the temperature dependences of the resonant FMR fields _res and _res for magnetic fields applied parallel and perpendicular to the normal to the film deviate from similar dependences for a free thin YIG plate, which approach the value of / for YIG. This deviation increases approximately in proportion to T^–1, reaching hundreds of Oe at T=4.2 K. It is established that the given effect is related to the additional static magnetic field H_p created in the YIG film by the paramagnetic substrate, and is dependent on the form of the latter.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 48–53, April, 1989.     

Hydrodynamic instability in a three-component electrochemical system

The Raleigh-Benard thermodynamic instability in electrochemical systems containing three types of univalent ionic components is considered for the case of a galvanostatic electrolysis. Dimensionless parameters characterizing the stability threshold and their critical values are found. Influence of an indifferent-electrolyte type and its concentration on the system stability is analyzed. A procedure is suggested for calculating the critical current from the dimensionless parameters at fixed physical characteristics of the system and initial concentrations of components     

Systems with electrocatalytic surface reactions: Effect of the coverage dependence of the adsorption and desorption rates

Stability of steady states and possibilities for the formation of multiplicity and oscillations under potentiostatic conditions are studied for various deviations from the Langmuir adsorption kinetics in systems containing one type of substance reacting electrochemically only via its adsorptive state. If the adsorbate-adsorbate interaction between molecules of substance X along the electrode surface is repulsive or does not occur, a stable steady state exists. The multiplicity of steady states and the periodical solutions emerge only if this interaction is attractive.     

Quantification of vestibular-induced eye movements in zebrafish larvae

Background  

Vestibular reflexes coordinate movements or sensory input with changes in body or head position. Vestibular-evoked responses that involve the extraocular muscles include the vestibulo-ocular reflex (VOR), a compensatory eye movement to stabilize retinal images. Although an angular VOR attributable to semicircular canal stimulation was reported to be absent in free-swimming zebrafish larvae, recent studies reveal that vestibular-induced eye movements can be evoked in zebrafish larvae by both static tilts and dynamic rotations that tilt the head with respect to gravity.     

Study of the total reactive dynamics of the H + DCl reaction within the framework of the quantum approach

The reactive dynamics of the H + DCl reaction was studied by the wave-packet method at an arbitrary total angular momentum. Two reaction channels (exchange and abstraction) are considered. The reaction cross sections calculated depending on collision energies up to 2.5 eV and initial states of the DCl molecule remain unchanged for the rotational levels j ₀ = 0, 1, 4 at a vibrational level v ₀ = 0. The reaction threshold and cross section agree with the known experimental data.     

Numeric Simulation of Natural Convection in Horizontal Layer of Binary Electrolyte at Constant Cell Voltage

Space dissipative structures resulting from convective instability of a binary electrolyte solution between two horizontal plane electrodes at a constant cell voltage are discussed. A system of hydrodynamic nonlinear equations is numerically integrated on a computer by the finite-difference method with spatial grid of 20 × 20. A relation between the applied voltage and Raleigh number is presented. The time dependences of current and electrode polarization during system relaxation towards steady state are obtained. The dependence of the electrode process acceleration due to natural convection on the applied voltage is found. The steady-state isolines of functions of current and concentration are constructed for some voltages. At too high Raleigh numbers, transition is observed to a turbulent mode.