Electrically controlled BST-Mg ceramic components for applications in accelerator technology

This paper reports on the results of an experimental investigation into the dielectric properties of a new composite ceramic material BSM, whose tunability increases with increasing concentration of the composite magnesium-containing additive. The main applications of the ferroelectric ceramic material in the accelerator technology are considered.     

Synthesis and sorption ability of telogenated hyper-cross-linked polydivinylbenzene networks

Synthesis and properties of hyper-cross-linked polymer networks prepared by radical polymerization of commercial divinylbenzene in oxylene, a good solvent and a powerful telogen, are reported. The permeability of hyper-cross-linked networks is evaluated by adsorption of bioactive molecules significantly differing in size. High sorption capacity for Cephalosporin C makes the polymers prepared promising for pharmacology and biotechnology.     

Wavelet-analysis of gastric microcirculation in rats with ulcer bleedings

Nitric oxide (NO) plays an important role in regulation of central and peripheral circulation in normal state and during hemorrhagic stress. Because the impaired gastric mucosal blood flow is the major cause of gastroduodenal lesions including ulcer bleeding (UB), we study in this work the NO-ergic mechanism responsible for regulation of this blood flow. Our study is performed in rats with a model of stress-induced UB using laser Doppler flowmetry (LDF) that characterizes the rate of blood flow by measuring a Doppler shift of the laser beam scattered by the moving red blood cells. Numerical analysis of LDF-data is based on the discrete wavelet-transform (DWT) using Daubechies wavelets aiming to quantify influences of NO on the gastric microcirculation. We show that the stress-induced UB is associated with an increased level of NO in the gastric tissue and a stronger vascular sensitivity to pharmacological modulation of NO-production by L-NAME. We demonstrate that wavelet-based analyses of NO-dependent regulation of gastric microcirculation can provide an effective endoscopic diagnostics of a risk of UB.     

Phase formation in the Ag2MoO4-CuO-MoO3 system and the crystal structure of the new double molybdate Ag2Cu2(MoO4)3

Subsolidus phase relations in the Ag₂MoO₄-CuO-MoO₃ oxide-salt ternary system were determined. T-x diagram was plotted for the Ag₂MoO₄-CuMoO₄ quasi-binary join. Double molybdate Ag₂Cu₂(MoO₄)₃ was found to exist on this join. This compound is a superstructure derived from orthorhombic Li₃Fe(MoO₄)₃. Its structure was solved in terms of a subcell (a = 5.0749(3), b = 11.300(2), c = 18.127(3) ?, space group Pnma, Z = 4, R = 0.0678). In the true unit cell, the parameter a is tripled; suggested space group is P2₁2₁2₁. A characteristic feature of the Ag₂Cu₂(MoO₄)₃ structure is infinite columns (extended along axis a) of face-sharing oxygen octahedra, in which disordered silver atoms are located (Ag(21), Ag(22), and Ag(23)) with various degrees of irregularity of their octahedral coordination and a strong anisotropy of thermal vibrations. Distorted CuO₆ octahedra form zigzag ribbons extended in the same direction. MoO₄ tetrahedra, which are arranged according to the pseudo-hexagonal law, link the aforementioned major structural elements into a three-dimensional framework. Trigonal-prismatic voids of the framework are occupied by silver atoms Ag (1). Presumably, the disorder of the silver ions in octahedral columns can be responsible for the increased ion conductivity of silver copper molybdate. A partial order of the same ions is the most likely reason for the appearance of superstructure with the tripled unit cell volume. Original Russian Text ? G.D. Tsyrenova, S.F. Solodovnikov, E.T. Pavlova, E.G. Khaikina, Z.A. Solodovnikova, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 5, pp. 802–809.     

Dynamics of electron spin in undulators

The problem on the evolution of electron spin in inhomogeneous magnetic fields of special type is solved on the basis of the classical Bargmann-Michel-Telegdi equation. The results obtained are used to analyze the behavior of electron spin in magnetic undulators. Moscow State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 38–40, January, 2000.     

Determination of Silicon Carbide Structures Layer Thicknesses using Reflection Spectra Frequency Analysis

Technical Physics - The paper introduces a method of determining thicknesses of single- and multi-layer silicon carbide structures using infrared reflection spectrum frequency analysis. Spectrum...     

Synthesis and cytotoxic activity of heterocyclization products of 1,1-dicyano-2-hetaryl-2-trifluoromethylethylenes

Methods for the synthesis of novel fluorinated compounds by reaction of 1,1-dicyano-2-hetaryl-2-trifluoromethylethylenes with a variety of nitrogen heterocycles have been developed. Cyctotoxicity of the obtained organofluorine heterocycles were studied in vitro at the U.S. National Cancer Institute (NCI) in the framework of the International Program for Development of Effective Antitumor Drugs. Cytotoxic activity in the series of fluorinated pyrazolo[1,5-a]pyrimidines has been observed for the first time, this strongly depending on the nature and position of the substituents.     

Synthesis and characterization of biodiesel fuel based of esters of tall oil fatty acids

Synthesis of esters from tall oil fatty acids and lower aliphatic alcohols is studied, and characteristics of the products as substitutes or components of diesel fuel are determined.     

Peculiarities of Quadrupolar Relaxation in Electrolyte Solutions

Peculiarities of quadrupolar relaxation in electrolyte solutions were established via comparison of the data obtained from proton and deuteron resonances. It has been shown that quadrupole coupling constants (QCC) of deuterons depend not only on internal electron structure of molecule or ion, but on solution structure as well. To interpret the experimental results quantum-chemical calculations of QCC of deuterons in different molecular complexes simulating different solution substructures were carried out. Density functional theory (DFT) method with hybrid B3LYP functional was used for all calculations.     

Formation of the HgI2 crystalline phase in the bulk and on the surface of nanocrystalline matrices

This paper reports on the results of investigations into the phase composition of HgI₂ microcrystals formed in the bulk and on the surface of different nanocrystalline matrices: pressed, finely dispersed (with a specific surface of more than 210 m²/g) aluminum oxide powders; porous borosilicate glasses with pore radii ranging from 2 to 20 nm; and Al₂O₃-HgI₂ and SiO₂-HgI₂ nanocrystalline composites. The results of spectroscopic analysis (diffuse reflection, absorption, and luminescence spectroscopy) are complemented by the data of atomic-force microscopy (AFM) and x-ray diffraction. The experimental results indicate that nonequilibrium modifications, namely, the high-temperature yellow phase and the orange phase metastable in bulk crystals at all temperatures, can be stabilized in HgI₂ nanoparticles at room temperature.