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Том 484, № 2 (2019)
- Год: 2019
- Статей: 4
- URL: https://journals.rcsi.science/0012-5016/issue/view/9257
Physical Chemistry
Kinetics of Chemical Processes in the Human Brain. Trigger Effect and Self-Stabilization of N-Acetylaspartic Acid
Аннотация
A kinetic model was proposed for the response of nerve tissue to an external signal stimulus. The model is based on the views of a multistep and non-linear nature of the dynamic variation of the concentrations of N-acetylaspartic acid and N-acetylaspartate in the human nerve tissue. The substrate inhibition effect in this system is a necessary factor for the self-stabilization of N-acetylaspartate as a key brain metabolite. The existence of three stationary states accounts for the trigger behavior of the system.
23-27
Electronically Mediated Reactions in Metal Thermal Reduction of Molybdenum and Tungsten Oxide Compounds
Аннотация
The reduction of tungsten and molybdenum oxide compounds (WO3, MoO3, MgWO4, MgMoO4, and CaMoO4) with calcium vapor at 800–860°С and a residual argon pressure of 5–10 kPa has been studied. As previously during the reduction with magnesium vapor, the spatial separation of the reaction products was observed, namely, the major portion of the calcium oxide formed in the reaction was deposited outside the reaction zone. A specific feature of the reduction of MgWO4 and MgMoO4 is that the magnesium is first replaced by calcium. The resulting magnesium metal acts as a reducing agent, and the magnesium oxide, along with calcium oxide, forms a crust on the surface of the reaction mass. Analysis of the experimental results shows that the reduction of oxide compounds with magnesium and calcium vapors at a residual argon pressure of more than 5 kPa proceeds via the electronically mediated reaction mechanism without direct physical contact between the reactants.
28-31
Effect of “Cobalt–Carbon Nanotubes” Catalysts on Anthracene Coking
Аннотация
Coking of anthracene at 400–600°C in the presence or in the absence of a cobalt catalyst supported on carbon nanotubes (CNTs) was studied for the first time. The coking products were examined by X-ray diffraction and electron microscopy. The CoO-CNTs catalyst considerably (by 50°C) decreased the temperature of the onset of coking and accelerated the coke formation. The presence of CoO-CNTs changed the coke morphology. Whereas coking of pure anthracene affords ~1 μm spherical particles of poorly crystallized carbon, in the presence of the catalyst, a carbon coat covering the CNT surface is formed.
32-35
Nanostructured ZrO2–Y2O3-Based System for Perovskite Solar Cells
Аннотация
ZrO2/Y2O3 nanoparticles containing 0, 3, and 10 mol % Y2O3 were synthesized under hydrothermal conditions. The structural and optoelectronic properties of the nanoparticles were studied using appropriate measurement techniques. From the synthesized ZrO2–Y2O3 nanostructured systems, electron-conductive thin-film photoelectrodes were fabricated and used to develop perovskite solar cells (PSCs) with the device configuration glass/FTO/ZrO2–Y2O3/CH3NH3PbI3/Spiro-MeO-TAD/Au. Comparative study of the PSC photovoltaic characteristics under 1000 W/m2 illumination (AM1.5G) has shown that the devices based on ZrO2–Y2O3 photoelectrodes exhibit a higher power conversion efficiency than the PSC based on undoped ZrO2 photoelectrodes.
36-38