Mechanism of reduction of thiosulfate ions on the cathode

The effect exerted by current density, cathode material (platinum, palladium, nickel, silver, copper, and cadmium), and temperature on the rate of the reduction of sodium thiosulfate was studied.     

Thermal stability of the microstructure of 12% chromium ferritic–martensitic steels after long-term aging at high temperatures

The structure of EK-181 (RUSFER-EK-181, low-activation) and ChS-139 12% Cr ferritic–martensitic steels is investigated and their mechanical properties are tested after long-term (13500 h) aging at 450 and 620°C. The microstructure of the steels exhibits a high thermal stability, which provides the retention of their initial short-term mechanical properties at test temperatures.     

Characteristic bands of the valence vibrations of the NO2 group in infrared absorption spectra. Part 1. Experimental data and band assignments

Frequency and intensity (integral and peak) are given for bands in the IR absorption spectra of 71 nitrocompounds; these are assigned to the symmetric valence vibration (1300–1400 cm^–1) of the C-NO₂ group and to the antisymmetric one (1500–1600 cm^–1). The splitting of the symmetric band is discussed in relation to resonance in the coupled vibrations of the nitro and methyl groups in saturated nitro-compounds.     

Nanoporous silicon doped by Cu for gas-sensing applications

The effect of hydrogen sulphide on the current–voltage characteristics of metal–insulator–semiconductor (MIS) structures based on nanoporous silicon (Si_nanopor) under copper doping has been investigated. Scanning electron (SEM), atomic force (AFM) and optic microscopes and/or secondary ion mass spectroscopy (SIMS) were used to obtain detailed characterisation of copper cluster distribution present at the surface and pores, respectively. SIMS spectra reveal that finite gradient in copper distribution along the pores and oxidation of nanoporous silicon simultaneously can be obtained successfully under electroless deposition process. It was also shown that the doping of nanoporous silicon by Cu leads to enhanced hydrogen sulphide sensitivity of MIS structures even without catalytic active top electrodes (for example, Pd) at room temperature. Furthermore, for different types of familiar MIS structures based on nanoporous silicon, e.g., MIS structures doped or undoped by copper and by using Pd metal electrodes, the hydrogen sulphide detection at room temperature mainly depends on the modification in the height of barrier of hetero- (Al–Cu–Si_nanopor–c-Si) or Schottky-like (Pd–Cu–Si_nanopor–c-Si) structures resulting the chemical interaction of molecular H₂S gas with copper clusters at the surface and in the pores. It is demonstrated that MIS structures based on the nanoporous silicon with copper doping are more sensitive to H₂S action at room temperature. In addition, the physical mechanism explaining the observed phenomena is also discussed.     

Stabilization of solutions to Shilov-type parabolic systems with nonnegative genus

We examine some class of Shilov-type parabolic systems with a nonnegative genus and bounded smooth coefficients depending on time and spatial variables and study the behavior of solutions when t tends to infinity. The initial data at t = 0 belong to a wide class of distributions.     

Cauchy problem for a class of degenerate kolmogorov-type parabolic equations with nonpositive genus

We study the properties of the fundamental solution and establish the correct solvability of the Cauchy problem for a class of degenerate Kolmogorov-type equations with { p^?,h^? } \left\{ {\overrightarrow p, \overrightarrow h } \right\} -parabolic part with respect to the main group of variables and nonpositive vector genus in the case where the solutions are infinitely differentiable functions and their initial values are generalized functions in the form of Gevrey ultradistributions.     

Cauchy problem with Riesz operator of fractional differentiation

In the class of generalized functions of finite order, we establish the correct solvability of the Cauchy problem for a pseudodifferential equation whose symbols are homogeneous functions of order γ > 0. We prove a theorem on the localization property of a solution of this problem. __________ Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 57, No. 12, pp. 1653–1667, December, 2005.