Crystal Structures of Endotaxic Phases in Europium Potassium Silicate Having a Pellyite Unit Cell

Crystallography Reports - The structures of three phases of the synthesized europium potassium silicate were determined by X-ray diffraction. Two of these phases crystallize in a new structural...     

Small-angle neutron scattering contrast variation on magnetite-myristic acid-benzene magnetic fluid

A magnetic fluid with magnetite dispersed in D-benzene and stabilized by myristic acid is investigated using the contrast variation technique in small-angle neutron scattering. The results obtained are interpreted within a new approach to the basic functions for polydisperse multicomponent and superparamagnetic systems. Myristic acid is considered an alternative to oleic acid, which is commonly used in these fluids. The parameters characterizing the particle size distribution function and the thickness of the myristic acid layer are determined. The data obtained are in good agreement with the results derived from previous investigations with the use of polarized neutrons.     

Crystal structure of complex natural aluminum magnesium calcium iron oxide

The structure of a new natural oxide found near the Tashelga River (Eastern Siberia) was studied by X-ray diffraction. The pseudo-orthorhombic unit cell parameters are a = 5.6973(1) Å, b = 17.1823(4) Å, c = 23.5718(5) Å, β = 90°, sp. gr. Pc. The structure was refined to R = 0.0516 based on 4773 reflections with |F| > 7σ(F) taking into account the twin plane perpendicular to the z axis (the twin components are 0.47 and 0.53). The crystal-chemical formula (Z = 4) is Ca₂Mg ₂ ^IV Fe ₂ ^(2+)IV [Al ₁₄ ^VI O₃₁(OH)][Al ₂ ^IV O][Al^IV]AL^IV(OH)], where the Roman numerals designate the coordination of the atoms. The structure of the mineral is based on wide ribbons of edge-sharing Al octahedra (an integral part of the spinel layer). The ribbons run along the shortest x axis and are inclined to the y and z axes. The adjacent ribbons are shifted with respect to each other along the y axis, resulting in the formation of step-like layers in which the two-ribbon thickness alternates with the three-ribbon thickness. Additional Al octahedra and Mg and Fe²⁺ tetrahedra are located between the ribbons. The layers are linked together to form a three-dimensional framework by Al tetrahedra, Ca polyhedra, and hydrogen bonds with the participation of OH groups.     

Modification of unsaturated rubbers in low-temperature plasma as a method to improve their adhesion properties

The change in the contact-surface properties of the films of unsaturated rubbers under the effect of a direct-current discharge has been investigated in case of the placement of the samples at the anode. It has been demonstrated that the modification in plasma leads to a substantial improvement in the contact properties of rubber films.     

Thermal polycondensation of hexakis(p-acetylphenoxy)-cyclotriphosphazene

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Behaviour of tetraalkylammonium ions in high‐field asymmetric waveform ion mobility spectrometry

High‐field asymmetric waveform ion mobility spectrometry (FAIMS) is an ion‐filtering technique recently adapted for use with liquid chromatography/mass spectrometry (LC/MS) to remove interferences during analysis of complex matrices. This is the first systematic study of a series of singly charged tetraalkylammonium ions by FAIMS‐MS. The compensation voltage (CV) is the DC offset of the waveform which permits the ion to emerge from FAIMS and it was determined for each member of the series under various conditions. The electrospray ionization conditions explored included spray voltage, vaporizer temperature, and sheath and auxiliary gas pressure. The FAIMS conditions explored included carrier gas flow rate, electrode temperature and composition of the carrier gas. Optimum desolvation was achieved using sufficient carrier gas (flow rate ≥2 L/min) to ensure stable response. Low‐mass ions (m/z 100–200) are more susceptible to changes in electrode temperature and gas composition than high mass ions (m/z 200–700). As a result of this study, ions are reliably analyzed using standard FAIMS conditions (dispersion voltage ?5000 V, carrier gas flow rate 3 L/min, 50% helium/50%nitrogen, inner electrode temperature 70°C and outer electrode temperature 90°C). Variation of FAIMS conditions may be of great use for the separation of very low mass tetraalkylammonium (TAA) ions from other TAA ions. The FAIMS conditions do not appear to have a major effect on higher mass ions. Copyright © 2010 John Wiley & Sons, Ltd.     

Complementarity of real-time neutron and synchrotron radiation structural investigations in molecular biology

General problems of the complementarity of different physical methods and specific features of the interaction between neutron and matter and neutron diffraction with respect to the time of flight are discussed. The results of studying the kinetics of structural changes in lipid membranes under hydration and self-assembly of the lipid bilayer in the presence of a detergent are reported. The possibilities of the complementarity of neutron diffraction and X-ray synchrotron radiation and developing a free-electron laser are noted.