Inversion of the density gradient and the diffusion “gate” in isothermal mixing of gases

The stable quasistationary mixing of ternary gas mixtures in a system of two chambers connected by a capillary is described by a theoretical model which predicts the density distribution of the mixture along the length of the diffusion channel. It is demonstrated that inversion of the density gradient can occur due to a nonlinear concentration distribution of the heavy component in a diffusion “gate” effect. The results obtained using this model are compared with the experimental data. Zh. Tekh. Fiz. 68, 14–17 (May 1998)     

Analogs of carbohydrate-metabolism coenzymes

Conclusions We synthesized two analogs of the natural coenzyme adenosine diphosphate glucose: N₆-methyl-ADPG and N₆, N₆-dimethyl-ADPG.For communication 11, see [1].The following abbreviations are used in this article: ADPG) adenosine-5'-diphosphate-a-D-glucopyranose; N₆-methyl-ADPG) N₆-methylamino-9--D-ribofuranosylpurine-5-diphosphate--D-glucopyranose; N₆, N₆-dimethyl-ADPG) N₆, Ng-dimethylamino-9--D-ribofuranosylpurine-5-diphosphate--D-glucopyranose.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2514–2521, November, 1969.     

An Approximation of Cross Sections of Channels of the 9Be(α, n) Reaction on the Basis of the Gamow Interaction Radius

Physics of Atomic Nuclei - Radiation transport of α-particles requires cross sections of inelastic interaction of α-particles with nuclei. At low energies the inelastic interactions are...     

Multidimensional exact solutions to the reaction-diffusion system with power-law nonlinear terms

We study a nonlinear reaction-diffusion system that is modeled by a system of parabolic equations with power-law nonlinear terms. The proposed construction of exact solutions enables us to split the process of finding the components depending on time and the spatial coordinates. We construct multiparametric families of exact solutions in elementary functions. The cases are elaborated of blow-up solutions as well as exact solutions time-periodic but spatially anisotropic.     

Approximation of Differential Cross Sections for Elastic Proton–Nucleus Scattering

Physics of Atomic Nuclei - An empirical approximation of differential cross sections for elastic proton–nucleus scattering over a wide energy range and for all target nuclei is proposed. In...     

High vacuum ionization chamber with high spatial resolution for monitoring synchrotron radiation beams

The possibility of using an ionization chamber with a cutting collectorin vacuum (10⁻⁴–10⁻⁵ Pa) for online monitoring of the position of a synchrotron radiation (SR) beam is studied experimentally The possibility of measuring the vertical position of the SR beam with a precision of up to several micrometers is demonstrated in the high vacuum conditions of an open channel in the VEPP-4M storage ring (in the absence of a beryllium window). Two such ionization chambers operating synchronously and situated one after another can serve as a basis for the SR beam stabilization system in neighboring channels.     

Stabilization of the nonautonomous potential systems with the forces of a dissimilar structure

The problem is considered of stabilizing a nonautonomous system given potential forces by adding some dissipative, gyroscopic, and nonconservative positional forces. The stabilizability domain is found for the relative equilibrium of a satellite in the circular orbit.     

Thermal sounding of the atmospheric boundary layer in the center of an oxygen absorption line

Radiophysics Scientific Research Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, No. 2, pp. 130–136, February, 1992.     

Effect of Pr-Ca substitution on the transport and magnetic behavior of LaMnO3 perovskite

The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO₃ perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good example of these properties is (La_1−2x Pr _x Ca _x )MnO₃ (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T _c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for understanding the structural, transport and magnetic properties are discussed in detail.     

Approximate number projection at finite temperature

The approximate particle number projection method based on an idea of the famous Lipkin — Nogami approximation is developed in the framework of the thermo field dynamics.