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This work presents studies of the electrocatalytic properties of ternary CoWRe alloys during the hydrogen-evolution reaction in KOH solution and their corrosion properties in KOH, H2SO4 and NaCl solutions. These alloys are electrodeposited from a citrate-pyrophosphate electrolyte with potassium-perrhenate concentrations of 0.01, 0.03, and 0.05 mol⋅l−1 . As shown, the use of such alloys makes it possible to increase the exchange current density by an order of magnitude and reduce the hydrogen overvoltage by 150 mV compared to electrolytic cobalt. An increase in the content of rhenium in the alloy leads to an increase in the overvoltage of hydrogen evolution in alkaline solutions: both in the KOH solution and in the electrolyte for the deposition of the alloy that explains the high current efficiency when obtaining alloys’ coatings. As shown, the highest corrosion resistance of such coatings with the ratio Re:W = 2:4 reaches 8.9 kΩ⋅cm² in NaCl solution, and in KOH solution, it is of 3.1 kΩ⋅cm², and corrosion resistance increases in time. [ABSTRACT FROM AUTHOR]

Corrosion behavior of electrolytic binary and ternary alloys in the 1 M KOH solution deposited from citrate-pyrophosphate electrolytes is studied. Based on the performed impedance measurements, the formation of a dense oxide layer which blocks the access of the electrolyte to the metal through cracks and pores is shown. Equivalent schemes have been selected and substantiated, and the parameters of the corrosion process have been calculated for 9 days of the samples exposure to the corrosive solution. Using chemical mapping it is shown that the corrosion product is predominantly cobalt oxide. A ternary alloy is characterized by a higher initial corrosion resistance of 6 kΩ×cm–2 and a significant polarization resistance after slowing down and stabilization of the corrosion process – 37 kΩ×cm–2. [ABSTRACT FROM AUTHOR]

Extraction systems based on extraction of tetrafluoroboric acid (HBF4) with tributyl phosphate (TBP) and triamylphosphine oxide (TAPO) for boron isotope separation were studied. Tetrafluoroboric acid was studied in comparison with boric acid (H3BO3). The extraction isotherms at 20°C for four systems (boric and tetrafluoroboric acids extracted with TBP and TAPO in o-xylene) were obtained, and single-stage isotope separation factors for these four systems were determined. The lighter boron isotope (10B) is concentrated in the aqueous phase in the systems containing tetrafluoroboric acid, whereas in the systems with boric acid it is concentrated in the organic phase. [ABSTRACT FROM AUTHOR]

Organic–inorganic composite ion-exchangers based on anion exchange resins have been obtained. Particles of one-component and two-component modifier were embedded using the approach, which allows us to realize purposeful control of a size of the embedded particles. The approach is based on Ostwald–Freundlich equation, which was adapted to deposition in ion exchange matrix. The equation was obtained experimentally. Hydrated oxides of zirconium and iron were applied to modification, concentration of the reagents were varied. The embedded particles accelerate sorption, the rate of which is fitted by the model equation of chemical reactions of pseudo-second order. When sorption of arsenate ions from very diluted solution (50 µg dm−3) occurs, the composites show higher distribution coefficients comparing with the pristine resin. [ABSTRACT FROM AUTHOR]

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The article has investigated the removal of anion-exchange forms of As(V) by organic anion-exchangers Dowex Marathon 11, Dowex SBR-P and organoinorganic anion-exchangers containing titanium oxyhydrate, from 0.2-2.0 mM solutions of NaHAsO in the range of equilibrium values pH 3-10. It has been found that introduction of an inorganic component in the amount of 7 fractions of total mass, % results in non-additive (up to 50 fractions of total mass, %) increase of absorption of ions of As(V) in adsorption from weakly alkaline solutions. It was assumed that nonadditive change of the value of absorption may be caused by the influence of the negative charge of the surface of oxide component of organic anion-exchangers. It is shown that in acid media and also at an increase of the amount of the introduced titanium oxyhydrate the values of adsorption and distribution coefficient of As(V) ions approaches additive ones. [ABSTRACT FROM AUTHOR]

The features of change in the structure and physical and mechanical properties of complex alloyed stainless austenitic steel are studied at elevated temperatures. Modes of hot plastic strain of the studied steel are proposed. [ABSTRACT FROM AUTHOR]

The structural changes that occur in a metastable austenitic Fe-Cr-Ni-based steel during cold plastic deformation by drawing and tension are analyzed. A relation between the structure of the steel and its mechanical and magnetic properties is established. It is concluded that the stress state scheme considerably affects the rate of martensite formation. [ABSTRACT FROM AUTHOR]

One of the approaches to enhance the bioavailability of nucleoside reverse transcriptase HIV inhibitors is the design of their prodrugs based on 1,3-diacylglycerols, which may simulate metabolic pathways of natural lipids, thus supporting the efficacy of drug delivery to the target cells. Glycerolipid AZT conjugates with different functional phosphoric centers were synthesized by the H-phosphonate technique. Stability of the prepared prodrugs against chemical and enzymatic hydrolysis (in buffer solutions and in the presence of pancreatic lipase), as well as their anti-HIV activity against the HIV-1 strain in human Tlymphoid MT-4 cells, were studied. [ABSTRACT FROM AUTHOR]

Special features of formation of structure and properties of high-alloy corrosion-resistant steels with different contents of the main components are studied after hardening from various temperatures and deformation with various degrees of reduction. [ABSTRACT FROM AUTHOR]

The structures of the bound 13C/2H double-labelled 2′(R/S), 5′(R/S)-2H2-1′,2′,3′,4′,5′-13C5-2′-deoxyadenosine and the corresponding 2′-deoxycytidine moieties in the complexes with human deoxycytidine kinase (dCK) have been characterized for the first time by the solution NMR spectroscopy, using Transferred Dipole-Dipole Cross-correlated Relaxation and Transferred nOe experiments. It has been shown that the ligand adopts a South-type sugar conformation when bound to dCK. [ABSTRACT FROM AUTHOR]