Corrosion resistance investigation of vanadium alloys in liquid lithium

A major concern in using vanadium alloys for first wall/blanket systems in fusion reactors is their activity with regard to nonmetallic impurities in the coolants. This paper presents the results of studying the corrosion resistance in high-purity liquid lithium (with the nitrogen and carbon content of less than 10^–3 wt %) of vanadium and vanadium alloys (V–1.86Ga, V–3.4Ga–0.62Si, V–4.81Ti–4.82Cr) both in the initial state and preliminarily irradiated with Ar+ ions with energy of 20 keV to a dose of 10²² m^–2 at an irradiation temperature of ~400°C. The degree of corrosion was estimated by measuring the changes in the weight and microhardness. Corrosion tests were carried out under static isothermal conditions at a temperature of 600°C for 400 h. The identity of corrosion mechanisms of materials both irradiated with Ar ions and not irradiated, which consisted in an insignificant penetration of nitrogen into the materials and a substantial escape of oxygen from the materials, causing the formation of a zone with a reduced microhardness near the surface, was established. The influence of the corrosive action of lithium on the surface morphology of the materials under study was found, resulting in the manifestation of grain boundaries and slip lines on the sample surface, the latter being most clearly observed in the case of preliminary irradiation with Ar ions.     

Kinetics of self-interstitials reactions in p-type silicon irradiated with alpha particles

New findings on the self-interstitial migration in p-type silicon are presented. They are based on experimental studies of the formation kinetics of defects related to interstitial carbon after irradiation with alpha particles. The main parameters characterizing the interaction rate of silicon self-interstitials with substitutional carbon atoms have been determined. A preliminary interpretation of the experimental data is given. The interpretation takes into account different diffusivities of self-interstitials in their singly and doubly ionized states.     

Electronic structure and properties of high-T c superconducting cuprates in the normal and superconducting phases within the LDA + GTB approach

Theoretical investigations of the properties of high-T _c superconducting cuprates within the LDA + GTB method taking into account the magnetic and phonon pairing mechanisms have been reviewed. These properties are the concentration-dependent electronic structure, quantum phase transitions with a change in the topology of the Fermi surface, and the superconducting phase of the $d_{x^2 - y^2 }$ symmetry.     

Synthesis, structures, and spectral properties of biomimetic azomethine metal chelates with chromophores CuN2S2, CuN2O2, and CuN2Se2. Crystal structure of bis[4-(benzyl)aldimino-3-methyl-1-phenyl-5-pyrazolothiolato]copper(II)

Copper(II) chelates of composition CuL₂ were synthesized based on 4-aminomethylene derivatives of 5-thiopyrazoles (LH). The complexes were studied by UV, IR, ESR, and EXAFS spectroscopy, magnetochemistry, and X-ray diffraction analysis. The coordination polyhedra in the complexes are pseudotetrahedra or octahedra of the types CuN₂S₂ or CuN₄S₂, respectively, which are distorted due to the Jahn—Teller effect. The UV and ESR spectra of copper chelates with a six-coordinate metallocycle formed by the N and S atoms of the azomethine ligand and the nitrogen atom of the quinoline substituent (R) of the C=N−R fragment are most similar to the spectra observed for metals involved in the active centers of natural metalloenzymes (“blue” copper proteins). Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1891–1896, November, 2000.     

Mixed crystals of p-dichlorobenzene with p-bromchlorobenzene in the presence of vacancies in the structure

Polarization studies of low-frequency Raman spectra of solid solutions of p-dichlorobenzene with p-bromchlorobenzene (50% p-dichlorobenzene) were carried out. Analysis of the lattice vibration spectra of these mixed crystals shows that vacancies can be present in their structure. The presence of vacancies is responsible for the emergence of additional lines, including those in the 70 cm^?1 region. The calculation of the diffusion activation energy in a mixed crystal proves that its magnitude is determined by the spatial arrangement of p-bromchlorobenzene molecules in the lattice, their orientation relative to parahalides, and (to a lesser extent) temperature variations.     

Electronic structure of layered compounds

The electronic structure of the intercalated graphite compounds XC₆ (X = Ca, Sr, Ba, Yb, and La) has been studied using the linearized augmented plane-wave method. It has been found that the electronic structure of the carbon layers in these compounds is qualitatively different from a two-dimensional graphite structure. A lower critical superconducting-transition temperature in YbC₆, as compared with that in CaC₆, at a higher electron density in the carbon layers can be explained by the strong hybridization of the p states of carbon and the d states of ytterbium near the Fermi level. An increase in the critical temperature would be expected in the compounds XC₆ with Group III metals, for example, in LaC₆.     

Polarized luminescence in a cubic liquid crystal

In a liquid-crystalline cubic phase the kinetics of the luminescence induced by pulsed excitation of a luminescing dopant has been studied. The influence of the molecular reorientation on the decay kinetics of the polarized components of the light has been investigated. The correlation times of the molecular reorientation and the magnitude of the local order parameter have been determined.     

Transition Metal Ion-binding Properties of a 14-Membered N2O2S2- Macrobicyclic Ligand

The selective liquid–liquid extraction of various transition metal cations from the aqueous phase to the organic phase was carried out using a 14-membered N₂O₂S₂-macrobicycle. Metal picrates such as Pb²⁺, Co²⁺, Zn²⁺, Ni²⁺,Cu²⁺ and Cd²⁺ were used in this extraction studies. It was found that the ligand showed moderate selectivity towards Pb²⁺ only among the other metals. The extraction constant (log K _ex) was determined to be 13.8 for Pb²⁺ complex.