Sorption behavior of cobalt in sulfuric acid solutions

Interaction of cobalt(II) ions with functional groups of sorbents based on amines, which additionally contain carboxyl (ANKB-35) and hydroxyl (SB-1, AN-31) fragments, is investigated. It is shown that the form of existence of the sorbent exerts an insignificant effect on cobalt absorption with ampholyte ANKB-35. Alternatively, anion exchangers AN-31 and SB-1 sorb cobalt in noticeable amounts only in the deprotonated form (OH^?). The analysis of obtained results on the cobalt sorption in equilibrium conditions as well as the IR spectroscopy provides clarification of specific features of the process. It is found that cobalt is adsorbed owing to the complex formation with nitrogen of amino groups of sorbents with the additional formation of bonds with carboxyl (ANKB-35) and hydroxyl (AN-31, SB-1) groups. In addition, the process is complicated by precipitation in the phase of sorbents according to the scheme Co²⁺ → Co(OH)₂ → Co(OH)₃. This effect is especially characteristic of the SB-1 anion exchanger, which contains a considerable amount of hydroxyl groups. The obtained data provide a justified choice of the ion exchanger and conditions of its use to concentrate Co²⁺ from solutions of sulfuric acid leaching of various cobalt-containing raw materials.     

Plasma Chemical Etching of Gallium Arsenide in C2F5Cl-Based Inductively Coupled Plasma

Semiconductors - The plasma chemical etching of gallium arsenide in chloropentafluoroethane (C2F5Cl) inductively coupled plasma is for the first time performed taking into account surface...     

Plasma-Chemical Deposition of Diamond-Like Films onto the Surface of Heavily Doped Single-Crystal Diamond

Semiconductors - The plasma-chemical deposition of diamond-like carbon (DLC) films onto heavily boron-doped single-crystal p-type diamond (the concentration ~1020 cm–3) in CH4 + Ar plasma is...     

Effect of polymer matrix and photoacid generator on the lithographic properties of chemically amplified photoresist

Resistive compositions based on ter-copolymers of isobornylacrylate with methylmethacrylate and (meth)acrylic acid, which are synthesized using the controlled radical polymerization with reversible chain transfer, as well as triphenylsulphoniumtriflate as a photo-sensitive catalyst are studied. The effect of the chain-transfer agent, as well as the composition and molecular weight of the copolymer on the sensitivity of the resists to UV radiation (222 nm), is determined. Using the ter-copolymer of tert-butoxycarbonyloxystyrene with methylmethacrylate and methacrylic acid, the dependence of the lithographic properties of the photoresist on the chemical composition of the photoacid generator is analyzed. The plasma-chemical stability of (co)polymer resists of methacrylic series in the plasma of Ar + SF₆ is studied.     

Coherent resonance in klystron oscillator at self-excitation threshold

The phenomenon of coherent resonance in a nonlinear dynamical system based on a delayed-feedback klystron (DFK) oscillator has been experimentally studied. The application of an external white noise signal to the DFK oscillator at the self-excitation threshold leads to the appearance of a resonant response in the system, the maximum of which is attained at a definite power of the external noise. It is demonstrated for the first time that the coherent resonance in response to an external harmonic signal in the microwave range allows the signal-to-noise ratio at the output of a regenerative ring amplifier to be significantly increased.     

Biodiversity of the vascular plants in the young fluvioglacial landscapes in the Severo-Chuiskiy centre of present-day glaciation (the Central Altai)

Abstract

This article reports the species richness of vascular plants in the young fluvioglacial landscapes in the Severo-Chuiskiy centre of present-day glaciation using the example of the fluvioglacial deposits of the mountain-glacial basin Aktru. These landscapes are four well distinguished classes of habitats: open pebble fields with minimal vegetation, young larch forests on elevated parts of the relief, shrub thickets on the banks of the Aktru river, and sites with ground-frazil near the valley slopes. There are 132 species of vascular plants in the young fluvioglacial landscapes. These include 36 families and 77 genera. There are 3 species of pteridophytes (only Equisetum), 4 species of gymnosperms, and 125 species of angiosperms. The highest species diversity was recorded for Asteraceae, Poaceae and Salicaceae families, and for Salix, Poa, and Carex genera. The highest species richness – 100 species – were recorded for open pebble fields. There were 76 species in the young larch forests, and 58 species occurred in shrub thickets. The lowest richness is characterised for the sites with ground frazil, where 31 species were recorded.