Quantum-Mechanical Model of Neural Network Elements

Physics of Atomic Nuclei - A model of a neural-network-like quantum-mechanical system is considered. The role of neurons is played by quantum-mechanical particles which evolve under the action of...     

Chemical Conversions of 8,18-Disubstituted Derivatives of 6,16-Diphenyl-1,2,3,11,12,13-hexahydrodibenzo[g,o]-4,14-dioxa-1,5,11,15-tetraazacyclohexadecine-2,12-diones

The chemical properties of 8,18-disubstituted 6,16-diphenyl-1,2,3,11,12,13-tetrahydrodibenzo[g,o]-4,14-dioxa-1,5,11,15-tetraazahexadecine-2,12-diones have been studied, including their interaction with N-nucleophiles (hydroxylamine, hydrazine, semicarbazide, and thiosemicarbazide), acidic and alkaline hydrolysis, and methylation. A hypothesis has been made from analysis of the mass spectral data of the thiosemicarbazide on the preferred existence of 6-substituted 4-phenylquinazoline-2-carbaldehydes in the gas phase as the linear tautomer.     

Crystal structure of (1,10-phenanthroline)ethylenediamine-<Emphasis Type="Italic">N,N′</Emphasis>-diacetatocopper(II) pentahydrate, [Cu(Edda)(Phen)] · 5H<Subscript>2</Subscript>O

The products of oxidation of ethylenediaminetetraacetic acid by manganese dioxide have been used to synthesize crystals of [Cu(Edda)(Phen)] · 5H₂O (Edda is ethylenediamine-N,N′-diacetate, and Phen is 1,10-phenanthroline). The X-ray diffraction analysis of the crystals shows that the N atoms of the Edda and Phen ligands lie in the equatorial plane around the Cu atom, and the O atoms of the Edda ligands are localized in more remote axial positions. The [Cu(Edda)(Phen)] complexes are grouped in pairs at a distance of 3.46 Å between the mean planes of the Phen ligands. Ten water molecules are united by hydrogen bonds into symmetric isolated clusters, and further they form a three-dimensional framework with the [Cu(Edda)(Phen)] complexes.     

Differential thermal analysis of Ag–Ge–Se,Ge–Se charge materials in the process of their heating and Ag8GeSe6, GeSe2 compound synthesis

This is the first comprehensive study of the processes of phase transformations (PT) and chemical reactions (CR) that accompany Ge–Se and Ag–Ge–Se charge material heating in stoichiometric proportions corresponding to GeSe₂ compounds, Ag₈GeSe₆ argyrodite and elementary selenium. The investigation was carried out by means of the differential thermal analysis (DTA) method. The PT in selenium and the main types of PT and CR of the formation of GeSe₂, Ag₈GeSe₆ compounds have been identified. The characteristic heats and temperature ranges of reaction processes have been determined. Ag₈GeSe₆ and GeSe₂ compounds formation has been experimentally demonstrated due to the DTA and X-ray analysis.     

Electronic Properties of Graphene Nanoribbons

Physics of Atomic Nuclei - Nowadays, graphene physics is aimed at finding a way to control the band gap of graphene, which is necessary for application of graphene in nanoelectronics. The purpose...     

Synthesis and structure of 3-arylidene and 3-hetarylidene-1,2-dihydro-3H-1,4-benzodiazepin-2-ones and their affinity toward CNS benzodiazepine receptors

The condensation of 5-aryl-7-bromo-1,2-dihydro-3H-1,4-benzodiazepin-2-ones with aromatic aldehydes gives 5-aryl-3-arylidene-and 5-aryl-7-bromo-3-hetarylidene-1,2-dihydro-3H-1,4-benzodiazepin-2-ones. X-ray diffraction structural analysis yielded the molecular and crystal structures of 7-bromo-3-(4′-methoxybenzylidene)-5-phenyl-1,2-dihydro-3H-1,4-diazepin-2-one and showed that this compound has cis configuration. Radioligand analysis was used to study the affinity of these products toward central nervous system and peripheral benzodiazepine receptors. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1213–1225, August, 2007.     

Crystals of Topological Vortices in Compact Electrodynamics

Physics of Atomic Nuclei - This study concerns the changes in the topological properties of four-dimensional compact lattice electrodynamics. The requirement of model compactness leads to the...     

Casimir energy calculations for Chern-Simons surfaces and dielectric plates within the formalism of lattice quantum field theory

A new method based on the Monte Carlo calculation on the lattice is proposed to study the Casimir effect in the noncompact lattice QED. This method can be used for Chern-Simons surfaces (thin metal films) and for dielectric plates.     

Determination of thermal conductivity of CVD diamond films via photoacoustic measurements

A novel method of determination of polycrystalline diamond films’ thermoconductive properties using the photoacoustic effect is proposed. By this method, we studied the diamond films grown on silicon substrates using chemical vapor deposition technique. A value of thermal conductivity obtained for the films was less than half that for diamond single crystal. The decrease of thermal conductivity, as well as characteristic features of optical properties of the films, is explained by the presence of a large amount of intercrystallite boundaries and other structure defects and admixures detected using Raman and photoluminescent spectroscopies. Received: 22 October 1998 / Accepted: 27 January 1999 / Published online: 28 April 1999     

Monte Carlo modeling of metallic hydrogen: the phase transition and the equation of state

We conducted numerical modeling of atomic (metallic) hydrogen using the PIMC (path integral Monte Carlo) method. The temperature and density range in which the electron (proton) behavior is governed by quantum (classical) statistics was studied. The equations of state in the form of dependences of the internal energy and pressure on temperature and density were obtained in that region. These dependences allow one to reveal and study the phase transition between crystal and liquid phases.