Ionization of Organic Compounds Affected by Laser Plasma Radiation at Atmospheric Pressure

Journal of Analytical Chemistry - The results of a study of the pathways of ion formation from organic compounds in Atmospheric Pressure Laser Plasma Ionization (APLPI) are presented. The...     

Investigation of Morphology and Chemical Structure of Nanosized Polytetrafluoroethylene Films Deposited on the Surface of Track-Etched Membranes by Plasma Processing

The morphology and chemical structure of nanosized polytetrafluoroethylene films deposited on the surface of track-etched poly(ethylene terephthalate) membranes by means of radiofrequency magnetron sputtering and electron-beam sputtering of the polymer in a vacuum have been studied using atomic force microscopy and X-ray photoelectron spectroscopy. It has been established that the morphology of films formed with the use of these coating techniques varies considerably. This is due to the size of the deposited polymer particles. The particles formed by the electron-beam sputtering of polytetrafluoroethylene are larger than those produced by magnetron sputtering of the polymer. It has been shown that the chemical composition of the films deposited by electron-beam sputtering in a vacuum is more in line with the composition and structure of the initial polymer than the films obtained by radiofrequency magnetron sputtering.     

Cyclotron dynamics of electron wave packets in topological insulators in an external magnetic field

The evolution of electron wave packets formed from surface states in topological insulators located in an external magnetic field is studied. The electron and spin densities of the wave packets under consideration are calculated analytically and are visualized. The influence of the main characteristics of the wave packets (the spin polarization) on the splitting and the change in their forms with time is considered.     

Magnetic ordering in granular system

The conditions of the formation of different magnetic structures with ferromagnetic (FM) and antiferromagnetic (AFM) ordering in granular materials containing a subsystem of ferromagnetic granules are considered within the phenomenological approach. It is supposed that the magnetostatic field and the exchange interaction between conduction electrons and magnetic ions are responsible for the formation of magnetic structure.     

Eu<Superscript>3+</Superscript> As a Luminescent Probe for Studying the Structure of R<Subscript>2</Subscript>O<Subscript>3</Subscript> Materials (R = Y,Eu, and Gd)

Spectra of Eu³⁺ in various dielectric matrices (Gd₂O₃:Eu³⁺, Y₂O₃:Eu³⁺, Eu₂O₃, and mSiO₂/Gd₂O₃:Eu³⁺ mesoporous particles) are studied by local cathodoluminescence. The results allowed identification of the local environment of Er³⁺ ions in amorphous samples and detection of the monoclinic Eu₂O₃ phase impurity in samples with yttrium oxide. The cathodoluminescence spectra of chemically pure Y₂O₃, Eu₂O₃, and Gd₂O₃ are recorded. Conclusions about the structural features of the materials are made and confirmed by other methods (XRD and EPMA).     

On the stability of solutions of stochastic differential inclusions

We study the stability in probability of a solution of a stochastic differential inclusion in a finite-dimensional space with nonrandom coefficients and a maximally monotone operator in the drift coefficient.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 47, No. 4, pp. 551–554, April, 1995.     

Steroids of the spirostan and furostan series of plants of the Allium genus. XXIII. Structure of cepagenin and of alliospirosides C and D from Allium cepa

Two new steroid glycosides of the spirostan series have been isolated from the fruit ofAllium cepa L. (family Liliaceae): alliospirosides C and D. On the basis of chemical transformations and spectral characteristics it has been established that the aglycon of both glycosides is a new steroid sapogenin — cepagenin — having the structure of (24S,25R)-spirost-5-ene-1,3,24-triol. Alliospirosides C and D are cepagenin 1-O-[O--L-rhamnopyranosyl-(12)-L-arabinopyranoside] and 1-O-[O--L-rhamnopyranosyl-(12)-O--D-galactopyranoside], respectively.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 843–849, November–December, 1987.     

Synthesis and Luminescent Properties of Gadolinium Tantalum Niobates Gd(NbxTa1 – x)O4

Optics and Spectroscopy - The feasibility of synthesizing gadolinium tantalum niobates by the liquid-phase method was demonstrated. The methods of X-ray diffraction, electron probe microanalysis,...     

Electronic and topological parameters of the skin layer in amorphous metallic ribbons after thermal annealing

Data on spectral polarimetric measurements in the range of 0.05–0.60 eV are presented, along with calculations on the optical characteristics of the surface layers of ribbons of the amorphous alloy Co₅₉Fe₅Ni₁₀Si₁₁B₁₅ before and after thermal annealing in order to determine how the composition of the surface layer changes during this treatment. It is shown that after annealing at a temperature of 425°C or above, the optical conductivity and the real and imaginary parts of the dielectric constant revert to the values for typical metals in the IR. This treatment produces microregions with an ordered structure in the surface layer. The experimental data show that for ribbons annealed at T = 475°C the spectral optical characteristics do not obey the Drude relations and behave similarly to their amorphous analogs.