Cadmium telluride nanofilms application in carbon monoxide detection
The research is centered on CdTe nanofilms. The article is aimed at developing innovative primary transducer nanoscale material for semi-conductor sensors, investigating their surface physicochemical properties and evaluation their applicability in carbon monoxide diagnostics. Cadmium telluride nanofilms were obtained by discrete thermal evaporation in vacuum. CdTe nanofilms applicability in gas analysis was investigated. Adsorption properties of the given material for carbon oxide (II) and oxygen were studied by the piezoquartz microweighing. The principles of adsorption, depending on the process conditions and the test sample habitus, were established. Based on the obtained experimental data, CO micro-impurities sensors were developed, the laboratory tests passed successfully.
New catalysts for the oxidation of carbon monoxide
Catalytic activity of binary and multicomponent semiconductors of the ZnSe-CdTe system prepared in a form of powders and nanofilms in CO oxidation was studied by pulsed flow and circulation flow methods. The conditions of maximal CO conversion were determined from the results of investigation of individual and joint adsorption of the reactants in a broad temperature range, and the specific activity of the catalysts was determined by the specific reaction rate at the specified temperature and composition of the reaction mixture. A noticeable catalytic transformation of CO on the semiconductors under study (up to 78.5%) was noted as low as room temperature. It was concluded that the oxidation of CO and adsorption of the CO + O2 mixture proceeds mainly by the collisional mechanism. It was noted that the high activity of studied catalysts already at room temperature (the (ZnSe)0.05(CdTe)0.95 solid solution possessed the highest activity) and the absence of high-cost metals in their composition allow us to recommend them as low-temperature, relatively low-cost catalysts for the neutralization of CO (carbon monoxide).
THE FIRST X-RAY IMAGING SPECTROSCOPY OF QUIESCENT SOLAR ACTIVE REGIONS WITH NuSTAR
We present the first observations of quiescent active regions (ARs) using the Nuclear Spectroscopic Telescope Array (NuSTAR), a focusing hard X-ray telescope capable of studying faint solar emission from high-temperature and non-thermal sources. We analyze the first directly imaged and spectrally resolved X-rays above 2 keV from non-flaring ARs, observed near the west limb on 2014 November 1. The NuSTAR X-ray images match bright features seen in extreme ultraviolet and soft X-rays. The NuSTAR imaging spectroscopy is consistent with isothermal emission of temperatures 3.1–4.4 MK and emission measures 1–8 × 1046 cm−3. We do not observe emission above 5 MK, but our short effective exposure times restrict the spectral dynamic range. With few counts above 6 keV, we can place constraints on the presence of an additional hotter component between 5 and 12 MK of ∼ 10 46 ?> cm−3 and ∼ 10 43 ?> cm−3, respectively, at least an order of magnitude stricter than previous limits. With longer duration observations and a weakening solar cycle (resulting in an increased livetime), future NuSTAR observations will have sensitivity to a wider range of temperatures as well as possible non-thermal emission.