Hydrocarbon specificity in the selective catalytic reduction of NOx over Cu-ZSM-5 and Co-ZSM-5 catalysts

Transformation of surface nitrates under CH₄ (CH₄+O₂) was found to ensure steady-state activity of Co-ZSM-5 in the selective catalytic reduction of nitrogen oxides by methane (CH₄-SCR). For Cu-ZSM-5, such species are mainly converted into NO. Relaxation of the coordination sphere due to oxygen and NO adsorption, stability of C,N-containing intermediates and activation routes of hydrocarbons (methane, propane) were analyzed as factors determining catalytic properties of Cu and Co cations.     

Changes in the IR internal reflection and absorption spectra of AK 60/40 polyamide films after the action of a glow discharge plasma

The modification of surface layers of AK 60/40 polyamide under the action of a gas discharge plasma was studied. Measurements were performed by infrared internal reflection spectroscopy. The results were analyzed to establish possible mechanisms of the interaction of a plasma with the polymer and structural changes in the polymer.     

Synthesis and properties of azoles and their derivatives. 35. Synthesis of certain azoles containing sterically hindered phenol residues

The condensation of hydrochlorides of ethyl iminoesters of 4-hydroxy-3,5-di-tert-butylbenzoic and -(4-hydroxy-3,5-di-tert-butylphenyl) propionic acids with monoethanolamine, o-aminophenol, and o-phenylenediamine was studied. As a result, ²-oxazolines, benzoxazoles, and benzimidazoles containing sterically hindered phenol residues in the 2-position were synthesized.For Communication 34, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 889–892, July, 1984.     

Magnetic Methods in a Study of the Effect of the Pore Structure of Silica Gels on the Particle Size of Cobalt in Catalysts for the Fischer-Tropsch Synthesis

A magnetic method was proposed for evaluating the average particle size of cobalt metal in supported cobalt catalysts for the Fischer-Tropsch synthesis. This method includes a set of techniques such as in situ temperature-programmed reduction and in situ temperature-programmed oxidation with simultaneous magnetization measurements and the dependence of magnetization on magnetic field intensity (the field dependence method). It was found that cobalt supported on silica gel with a bimodal pore-size distribution exhibited a special behavior in topochemical processes: the majority of cobalt particles occurred in a superparamagnetic state, while a portion occurred in a multidomain state.     

Processing of coked Pt-Re/γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalysts with high-concentration ozone dissolved in supercritical carbon dioxide

The potentialities of low-temperature (50–150°C) regeneration of coked Pt-Re/γ-Al₂O₃ bimetallic catalysts of reforming with high-concentration ozone dissolved in supercritical carbon dioxide (SC-CO₂) are examined. Raman spectroscopy, thermogravimetric, and differential microcalorimetric studies show that solid organic deposit (coke), a by-product of the reforming process, can be partially removed from the mesoporous surface of a coked catalyst by processing with an O₃/SC-CO₂ mixture without any loss of the active components (Pt, Re). Treatment of coked Pt-Re/γ-Al₂O₃ catalysts with an O₃/SC-CO₂ mixture causes changes in the parameters (extent of conversion, selectivity) of the catalytic reforming of n-heptane.     

Influence of growth conditions on the surface quality and structural perfection of multicomponent heterostructures based on group A3B5 compounds

The surface quality of epitaxial multicomponent layers based on group A³B⁵ compounds, which are grown under different conditions via floating-zone refining with a temperature gradient, is comprehensively analyzed. The main parameters (temperature gradient, solution-melt composition, supercooling level, matching between lattice parameters and the thermal expansion coefficients of the layer and substrate, and substrate orientation) affecting the surface quality and structural perfection of the heterostructures are determined.     

Features of Laser-Induced Modification of Sclera and Cornea

Results are presented from studying collagen degradation in scleral and corneal tissues upon CW IR laser irradiation at a wavelength of 1.56 μm and powers of 1.4 and 7 W. The exposure time is such that the radiometrically determined maximum tissue temperature ranges from 55 to 70°C. It is shown that at a power of 1.4 W, laser-induced collagen denaturation in sclera and cornea starts at 55 and 60°C, respectively. When the power is increased to 7 W, the temperature of denaturation onset rises by 2°C. These findings are discussed from the viewpoint of the joint photothermal and photomechanical effects of laser irradiation.