Deep Learning Techniques Applications for the ENDA Experiment Data Analysis

Physics of Atomic Nuclei - Abstract-Using of machine learning (ML) and deep learning (DL) techniques in data analysis becomes a mainstream today and is presented in papers of leading experiments....     

Quadrupole effects in the NMR spectra of 27Al in disordered mixed compounds CaREAlO4 (RE=La, Pr, Eu, Y)

The NMR spectra of ²⁷Al are measured in several disordered rare-earth aluminates CaREAlO₄. A change in the shape of the resonance line of the transition 1/2↔−1/2 in the transverse orientation in the rare-earth series RE=La, Pr, Eu, Y is observed, from a narrow (∼16 kHz), structureless line in the La compound to a wide (∼130 kHz), three-component line in the Y compound. This is attributed to a nonuniform distribution of the electric field gradient tensor at the ²⁷Al site. The electric field gradient tensor at the ²⁷Al site in a cluster (AlO₆)⁻⁹ is calculated by a nonempirical method (MO LCAO SCF) in the “deformable oxygen octahedron” model. The results are found to be in satisfactory agreement with the experimental values of 〈V _zz〉 and can be used to obtain the experimental splitting of the resonance line in the Y compounds for reasonable values of the parameters of the local deformations of the AlO₆ octahedron. The nature of the strong axial correlations in the distribution of the Ca and Y atoms in CaYAlO₄ is discussed. Fiz. Tverd. Tela (St. Petersburg) 39, 618–623 (April 1997)     

Simulation of Molecular Dynamics of the Tetrapeptide Ala-Gly-Asp-Pro

A quantum-chemical calculation procedure intended for studying geometries and electronic structures of various peptides was tested using the tetrapeptide Ala-Gly-Asp-Pro as example. The trajectory of the molecular dynamics of the Ala-Gly-Asp-Pro molecule in the surrounding of water molecules was followed for a period of 1500 ps. The conformation of the peptide molecule does not change within this period. The water surrounding of the Ala-Gly-Asp-Pro molecule prevents formation of an intramolecular salt bridge between the nitrogen atom of the terminal amino group and oxygen atoms of the side carboxy group of Asp. It is suggested that the mechanism of the physiological action of Ala-Gly-Asp-Pro may involve hydrogen bonding with one or several functional groups of this molecule.     

The acylation of 2-butyne by derivatives of 1- and 2-adamantanecarboxylic acids

Conclusions The acylation of 2-butyne by derivatives of 1- and 2-adamantanecarboxylic acid leads to the formation of 1,2-disubstituted and condensed adamantane derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2515–2521, November, 1979.     

Complexes of arenechromium compounds with 7,7,8,8-tetracyanoquinodimethane

Conclusions For the first time complexes of arenechromium compounds with 7,7,8,8-tetracyanoquinodimethane were obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2124–2125, September, 1968.     

Acylation of alkynes by α-bromobutyroyl tetrafluoroborate

Conclusions The acylation of alkynes by -bromobutyroyl tetrafluoroborate under nonnucleophilic conditions takes place as a reaction involving the conjugated addition of the acylium cation and the bromide anion from the acyl residue over the triple bond by means of a 1, 4 shift.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1077–1080, May, 1978.     

Orientational processes in the yarns of high-molecular-mass cellulose acetate in vapors of nitromethane and its mixture with water

The phenomenon of spontaneous changes in the linear dimensions (elongation-contraction) is described for commercial and laboratory samples of acetate yarns processed by wet spinning from high- molecular -mass cellulose diacetate in vapors of a mesophas ogenic solvent (which is able to form a lyotropic LC phase with the polymer), nitromethane, and its mixtures with water. The thermodeformational, elastic- plastic, physicomechanical, and surface characteristics of the yarns at different stages of their spontaneous deformation are analyzed. When samples are treated with probe vapors, orientational processes in the polymer matrix are activated, and this observation makes it possible to prepare yarns with improved physicomechanical characteristics and with low linear density. A new phenomenon (to our knowledge) of cyclic three- stage deformation of acetate monofilaments in nitromethane vapors is discovered. This evidence is interpreted from the standpoint of phase (amorphous glassy-liquid crystalline state) and conformational transitions as well as by the mechanism of interaction between polymers and solvent vapors and related development of the LC phase.     

Primary Cosmic Ray Energy Spectrum Above the ‘‘Knee’’ Measured with PRISMA-32 Array

Physics of Atomic Nuclei - PRISMA-32 (PRImary Spectrum Measurement Array) is working since 2012 in the Scientific & Educational Center NEVOD (NRNU ‘‘MEPhI’’,...     

On the stability of oscillations representable by Fourier series with slowly varying parameters

For a quasilinear almost triangular differential system whose coefficients are representable by trigonometric series with slowly varying coefficients and frequency, we obtain conditions for the existence of a particular solution of similar structure and study the stability of this solution.