Large Numbers Generated by the Riemann Zeta Function

Journal of Experimental and Theoretical Physics - Anomalously large numbers generated of the Riemann zeta function are analyzed. A set of Mersenne primes is investigated. The equations connecting...     

Experimental and Theoretical In Situ Spectral Magneto-Ellipsometry Study of Layered Ferromagnetic Structures

JETP Letters - The influence of antiadiabatic phonons on the superconducting transition temperature is considered within Eliashberg-McMillan approach in the model of discrete set of (optical)...     

Weak Antiferromagnet Iron Borate FeBO3. Classical Object for Magnetism and the State of the Art

Journal of Experimental and Theoretical Physics - The simple lattice and magnetic structure, the high Néel temperature, the narrow antiferromagnetic resonance line of FeBO3, and the narrow...     

External electric field effect on electronic properties and charge transfer in CoI2/NiI2 spinterface

Electronic structure and spin-related properties of CoI₂/NiI₂ heterostructure were studied by means of density functional theory. It was shown that the electronic structure at the Fermi level can be characterized by a band gap. The effect of the external electric field on charge transfer and electronic properties of the CoI₂/NiI₂ interface was investigated, and it was found that band gap width depends on the strength of the applied electric field, switching its nature from semiconducting to a half-metallic one. An easy control of the electronic properties and promising spin-polarized nature of the CoI₂/NiI₂ spinterface allows the heterostructure to be used in spin-related applications.     

Magnetic Properties of FeBO3 in the Low-Spin State

JETP Letters - Changes in the magnetic properties of FeBO3 single crystals in the course of spin crossover occurring with increasing pressure up to 63 GPa are studied both experimentally and...     

Spin-Flop Transition in Co2B2O5 Pyroborate

JETP Letters - Recent theoretical ideas concerning the mechanism of the electromagnetic proximity effect in hybrid superconducting structures with ferromagnetic layers, as well as the problem of...     

Spectral-luminescence and quantum-chemical study of the anionic forms of 5-fluorouracil

A spectral-luminescence study of neutral (pH 7) and alkaline (pH 11 and 14) aqueous solutions of the anticancer drugs 5-fluorouracil (FU) and tegafur has been performed. The fluorescence spectra of the N3- and N1-centered anions of 5-fluorouracil, its dianion, and the tegafur monoanion with emission maxima at wavelengths (λ_em) of 358, 372, 366, and 358 nm and photoluminescence quantum yields (φ) of 11.2 × 10^–4, 35.1 × 10^–4, 26.5 × 10^–4, and 8.6 × 10^–4, respectively, have been recorded for the first time. The fluorescence characteristics of the FU anionic forms have been related to the magnetic shielding constant as one of the criteria of aromaticity.     

Thermochemistry of Heteroatomic Compounds. Enthalpy of Dissolution and Vaporization of Selected Trimethylsilyl Di- and Tetrathiophosphates

Russian Journal of General Chemistry - Enthalpy of vaporization (ΔvapH°) of trimethylsilyl esters of dithio- and tetratiophosphoric acids (RX)2P(S)SSiMe3 (X = O, S) have been determined...     

Determination of natural aromatic acids using supercritical fluid chromatography

Derivatives of benzoic and cinnamic acids are secondary metabolites of plants, widely distributed in nature and possessing biological activity. Supercritical fluid chromatography (SFC) is shown to provide a high performance separation of nine most important representatives of this class of compounds with selectivity, dramatically different from the reversed-phase high-performance liquid chromatography. The retention and chromatographic separation parameters of analytes for four stationary phases of different nature are compared and the effect of supercritical fluid parameters and the composition of the mobile phase onto the chromatographic separation are analyzed. The optimal separation is found to be achieved when using a silica-based sorbent with 2-ethylpyridinium linked groups. The proposed approach for determination of the above-mentioned compounds is based on the combination of chromatographic separation with multiwavelength spectrophotometric detection and provides the detection limits in the range of 13.0–51.3 μg/L and the analysis duration about 2.5 min. The approach is successfully tested on real objects, such as different kinds of wine.     

A review of furfural derivatives as promising octane boosters

Prospects for using furfural derivatives as octane boosters for gasoline are discussed on the basis of analysis of their physicochemical and operation properties. Knock resistance data, toxicity parameters, and results of motor bench tests are considered for furan compounds, furfural ethers, furfurylamine, and other furfural derivatives.