Operational Impedance of an Li–CFxCell

An operational-impedance approach to functional testing of lithium cells during their service is discussed. Operational-impedance spectra for a lithium cell discharged to different levels are taken. Parameters of its equivalent circuit are determined. The dependence of the cell's electrolyte resistance on the depth of discharge may be used for estimating the cell's efficiency long before a total discharge.     

Low-viscosity flow of a solid dispersed medium in the Bridgman effect

The quasi-fluid flow of microdispersed solids at the stage of rapid dynamic high-pressure loading under the conditions of the Bridgman effect is considered in terms of the hydrodynamic approach. Under these conditions, the effective dynamic viscosity of the rapidly flowing solid medium is estimated to be η = 1–3 Pa s, which is typical of only low-viscous fluids. The time of dynamic loading at the stage of rapid compression in the Bridgman effect is estimated as t = (3–6) × 10⁻⁶ s, which agrees well with the available experimental data.     

On the temperature frequency coefficient of a quantum cell containing Rb87 vapors

The physical processes are investigated which affect the temperature coefficient of frequency of a quantum cell containing Rb⁸⁷ vapors. It is shown that the total temperature coefficient of frequency (TCF) of the cell is determined by the composition of the gas mixture, the frequency drift of the standard atomic transition due to the action of the pumping light, and the adsorption of the gas mixture on the inside surface of the cell.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 15, No. 4, pp. 528–532, April, 1972.     

Degradation mechanisms of MEA characteristics during water electrolysis in solid polymer electrolyte cells

The processes contributing to degradation of characteristics of membrane-electrode assemblies (MEA) of water electrolyzers with solid polymer electrolyte (SPE) are considered. Particularly, the life tests of an electrolysis cell with SPE reveal the migration of platinum from the cathodic active layer and its deposition in membrane’s near-cathode region. In addition to platinum, several other elements (Ti, Ir, Fe, Ni, Si) are detected in the membrane, carried there with the water-reagent from the structural elements of MEA, electrolysis cell, and its outer framing (anodic electrocatalytic layer, half-cells, tubes, water tank-separator, etc.). The observed considerable loss of platinum in the cathodic catalytic layer leads to a decrease in its activity (due to the decrease in concentration of platinum nanoparticles and the loss of their cohesion), while the appearance in the membrane of platinum and other ions that have the lower mobility as compared with hydrogen ions gives rise to modifications in the membrane structure thus increasing the electrolysis potential in the course of life tests.     

Recognition of Artificial Nucleobases by E. coli Purine Nucleoside Phosphorylase versus its Ser90Ala Mutant in the Synthesis of Base‐Modified Nucleosides

A wide range of natural purine analogues was used as probe to assess the mechanism of recognition by the wild‐type (WT) E. coli purine nucleoside phosphorylase (PNP) versus its Ser90Ala mutant. The results were analyzed from viewpoint of the role of the Ser90 residue and the structural features of the bases. It was found that the Ser90 residue of the PNP 1) plays an important role in the binding and activation of 8‐aza‐7‐deazapurines in the synthesis of their nucleosides, 2) participates in the binding of α‐D ‐pentofuranose‐1‐phosphates at the catalytic site of the PNP, and 3) catalyzes the dephosphorylation of intermediary formed 2‐deoxy‐α‐D ‐ribofuranose‐1‐phosphate in the trans‐2‐deoxyribosylation reaction. 5‐Aza‐7‐deazaguanine manifested excellent substrate activity for both enzymes, 8‐amino‐7‐thiaguanine and 2‐aminobenzothiazole showed no substrate activity for both enzymes. On the contrary, the 2‐amino derivatives of benzimidazole and benzoxazole are substrates and are converted into the N1‐ and unusual N2‐glycosides, respectively. 9‐Deaza‐5‐iodoxanthine showed moderate inhibitory activity of the WT E. coli PNP, whereas 9‐deazaxanthine and its 2′‐deoxyriboside are weak inhibitors.     

A study of electrodes based on fluorinated fullerene black

Original method for fabrication of cathodes based on fluorinated fullerene black for primary lithium power cells was developed. The method includes preliminary ultrasonic treatment of the active mass.     

High-resolution transmission measurements of CO2 at high temperatures for industrial applications

High-resolution transmission spectra of CO₂ in the 2.7, 4.3 and 15 μm regions at temperatures up to 1773 K and at approximately atmospheric pressure (1.00±0.01 atm) are measured and compared with line-by-line calculations based on the HITEMP-1995, HITEMP-2010, CDSD-HITEMP and CDSD-4000 databases. The spectra have been recorded in a high-temperature flow gas cell and using a Fourier transform infrared (FTIR) spectrometer at a nominal resolution of 0.125 cm^?1. The volume fractions of CO₂ in the measurements were 1, 10 and 100%. The measurements have been validated by comparison with medium-resolution data obtained by Bharadwaj and Modest [6]. The deviations between the experimental spectra and the calculations at 1773 K and the vibrational energy exchange and thermal dissociation of CO₂ at high temperatures are discussed.     

Heavy ion beam scanning system of DC-110 accelerator

A heavy ion acceleration complex for industrial applications based on the DC-110 cyclotron has been developed at the Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research. It is planned to irradiate polymer films with a width of up to 600 mm at this complex. This paper presents a design of a system for scanning heavy ion beam which offers uniform film irradiation at a beam energy of up to 2.5 MeV/nucleon. The general concept of the two-channel scanning system and the design of the main deflecting magnets are described.     

Classical and Quantum Integrable Sigma Models. Ricci Flow, “Nice Duality” and Perturbed Rational Conformal Field Theories

Journal of Experimental and Theoretical Physics - We consider classical and quantum integrable sigma models and their relations with the solutions of renormalization group equations. We say that an...     

Operator algebra of two-dimensional conformal theories with central charge C ≤ 1

Structure constants of operator algebras in conformal theories with central charge C ≤ 1 are explicitly calculated.