Synthesis and properties of magnetic semiconductor InSb〈Mn,Cd〉

Polycrystalline indium antimonide samples codoped with manganese (0.8–1 at %) and cadmium (3.9 at %) are prepared by quenching from melt. Despite the high contents of these dopants, only InSb maxima are observed in X-ray diffraction patterns of these samples. As probed by magnetic studies, the samples are ferrimagnets having Curie points of about 577 K and room-temperature specific magnetizations of σ ≈ 0.5 G cm³/g (H = 6 kOe). We suggest that the magnetic properties of the samples are dictated by InSb〈Mn,Cd〉 microinclusions, which are located in grain boundaries and dislocations.     

Micromagnetic Analysis of Edge Effects in a Thin Magnetic Film during Local Excitation of Magnetization Oscillations

Russian Physics Journal - The method of numerical micromagnetic simulation was used to study the magnetization dynamics of a thin film with uniaxial magnetic anisotropy during ferromagnetic...     

Artifacts in the determination of intravenous anesthetics by gas chromatography-mass spectrometry: Tramadol, the correlation between the structures of metabolites and impurity substances

The simultaneous determination of preparations used for multicomponent intravenous anesthesia (Promedol, tramadol, ketamine, diazepam, Thiopental, and phentanyl) and of their metabolites in blood and urine of surgical patients by chromatography-mass spectrometry was considered. Artifacts due to the Chromatographie interference of various preparations and their metabolites were revealed. The lability of the anesthetics and their metabolites in the course of sample preparation and analysis by gas chromatography (GC) was examined. The degradation products of the test preparations responsible for the generation of false positive results were found. Phentanyl, Promedol, ketamine, tramadol, Thiopental, diazepam, and their metabolites excreted with urine in the free forms were determined in the whole blood and urine of surgical patients. Bound forms of metabolites and the initial medicinal preparations excreted as complexes with glucuronic acid and other acids were also determined in urine. Metabolites and impurity substances in the intravenous anesthetics with similar mass spectra and retention times were distinguished. Methodological recommendations concerning the analysis of difficult-to-separate (by capillary gas chromatography) pairs of substances used for intravenous anesthesia and their metabolites are given. The following pairs of components are difficult to separate: Norpromedol-2-methylamino-5-chlorobenzophenon (a product of diazepam hydrolysis), norketamine-Promedol, and anhydrotramadol (a GC artifact)-ketamine. The cumulation of an impurity substance from the tramadol preparation, identified by us as epoxytramadol, in the body was examined.     

Simulation of the effect of hydroxyethylidenediphosphonic acid on the kinetics of copper(II) oxide dissolution in sulfuric acid

The effect of hydroxyethylidenediphosphonic acid (HEDP) on the kinetics of copper(II) oxide dissolution in aqueous sulfuric acid was studied. The addition of HEDP in acidic media decreases the CuO dissolution rate. The simulation of these processes showed that the inhibiting effect is due to the decrease in the concentration of the intermediate compound (CuOH⁺), which restricts the dissolution of Cu²⁺ ions, due to adsorption of the HEDP ions (H₄Y^?) on the oxide surface.     

Synthesis and study of the magnetic characteristics of nanocrystalline cobalt films

The effect of various technological factors on the main magnetic characteristics of nanocrystalline cobalt films obtained by chemical deposition is studied. The effective saturation magnetization, uniaxial anisotropy, coercive force, and other characteristics of local spots of films were measured using a scanning FMR spectrometer over the decimeter wavelength range. A technique for preparing substrates is developed, and the optimum technological conditions of thin-film synthesis are found making it possible to significantly decrease magnetic inhomogeneities across the area and thickness of samples. It is shown that one can significantly decrease the FMR linewidth and increase the magnetic permeability of films in a given microwave frequency range.     

Cleavage of C<Subscript>60</Subscript> fullerite crystals

It is found that, under certain conditions, C₆₀ fullerite crystals can be cleaved along cleavage planes that are close-packed planes of the {111} type. Rigid gas-phase grown crystals exhibit good cleavage properties. In experiments with active compressive deformation, these crystals showed a high yield point τ_y = 2.65 MPa, a “parabolic” stress-strain curve, and brittle fracture after attaining a shear strain of about 8%. The fracture surface was clearly seen to have fragments parallel to the (111) plane. Typical microstructures observed in the cleavage plane are discussed: crystallographic cleavage steps, an indentation pattern, and a dislocation prick rosette. The fact that the activation volume V ? 60b³ is small (b is the Burgers vector of a dislocation) and strain-independent indicates the Peierls character of fullerite deformation or dislocation drag in a dense network of local defects.