Isolation and characterization of the polysaccharide ofSophora japonica fruit

Simferopol' State University, and Kursk State Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 748-749, September-October, 1995. Original article submitted March 10, 1995.     

A method of rectifying current at microscales

A method for rectifying electric current in micro and nanoscale devices is proposed based on the asymmetric concentration of polarization in an electrolyte solution in the case where the current in a microdiode successively passes through two mutually undissolvable fluids with different dielectric constants and diffusion coefficients in tubes with different dimensions. It is assumed that both fluids contain the ions of a completely dissociated substance which provide electric charge transfer upon application of a potential difference to the walls of the device, and the interface between the two fluids has a charge. The process is described by a one-dimensional nonstationary Nernst-Planck-Poisson system. The boundary conditions on the electrodes are the impermeability condition for anions and the Arrhenius equation which defines the flow of cations. The system of equations was solved numerically: the unknowns were decomposed into a complete system of orthogonal functions of the spatial variable, and the resulting dynamical system for the Galerkin coefficients was integrated over time by the Gear method because of its stiffness. The parameters of the system that have the most significant effect on the degree of rectification are determined, and their optimum values are evaluated.     

Searching for Neutrino and Ultra-High-Energy Gamma-Ray Counterparts of the GCN Alerts

Physics of Atomic Nuclei - The Baksan Neutrino Observatory setups are currently performing search for neutrino and ultra-high-energy gamma-ray counterparts of the events on the Gamma-ray...     

Methods and Devices for the Preparation of Standard Gas Mixtures

A review of methods for the preparation of standard gas mixtures (SGMs) with the known concentrations of organic and inorganic gases and vapors is presented. The classification of methods is proposed and their advantages and disadvantages are compared. Along with the widely known thermal diffusion and gasextraction methods and devices for the preparation of SGMs functioning on their basis, i.e., sources of gas and vapor microflows and vapor-phase sources of gas mixtures, the review considers and discusses metrological possibilities proposed by Russian researchers of chromatomembrane and chromato-desorption methods of SGM preparation and corresponding instrumentation.