Thermal properties of manganese-doped ZnO polycrystalline films

The thermal conductivity and heat capacity of manganese-doped zinc oxide polycrystals have been studied in the temperature range 30–300 K. A substantial influence of the secondary phase or MnO clusters formed as a result of doping on the temperature dependences of thermophysical properties of polycrystalline zinc oxide films has been shown.     

The effects of normal current density and the plasma spatial structuring in argon DBDs

This paper presents the results of theoretical studies of high-pressure dielectric barrier discharges (DBD) in argon. Two different DBDs at the megahertz and the kilohertz power frequency range were simulated. The effect of normal current density was obtained in the numerical model for both types of the discharge. The discharge of megahertz range was uniform over the radius. The increase in the discharge current is accompanied by increase in the discharge area. The discharge of kilohertz range is not uniform over the radius. The concentric ring formation was observed during calculations. The increase in the discharge current occurs due to increase in the number of rings and as a result in the discharge area. The developed 2D model is able to describe only the first stage of the filament formation – the formation of concentric plasma rings. The filament formation starts at the edge of the current channel and spreads to its centre. Both the effect of normal current density and the filaments formation are caused by the nonstationarity at the current channel boundary.     

The influence of the discharge parameters on the plasma spatial structuring in argon DBDs

The plasma parameters, discharge plasma uniformity and filamentation processes in high pressure (near atmospheric pressure) dielectric barrier discharges (DBD) in argon are studied using the developed two-dimensional 2D(r, z) model. The applied voltage frequency, the voltage shape, the dielectric layers material and its thickness are varied and the effects of such variations on plasma uniformity, discharge structure and operation are studied. The DBD discharges with different dielectric layers thickness, dielectric constants and secondary electron emission coefficients are simulated. It was shown that the dielectric layer thickness is an important parameter for producing high pressure discharges uniform over the radius. The possibility of the radially uniform discharges at atmospheric pressure was shown in the present study.     

The structure of thin carbon films deposited at 13.5 nm EUV irradiation

In this work, the structure and chemistry of thin nm-thick carbon films deposited on a substrate using strong 13.5 nm EUV irradiation under a strong vacuum were studied. The film structure was studied by Raman spectroscopy in comparison with the Raman spectra of well-known carbon phases: diamond, single-wall nanotubes, nano- and micro-crystalline graphite and amorphous carbon. As well, FTIR spectroscopy was used to study possible IR-active chemical bonds, primarily, hydrogen bonds. It was shown that films deposited on a surface under EUV irradiation consists of amorphous sp ²-carbon. The mechanisms of deposition are discussed briefly. Knowledge about the structure and chemistry of such carbon films is very important for EUV lithography.     

Multicomponent reactions of amines with aldehydes and H<Subscript>2</Subscript>S as efficient route to heterocycles and thioaza macrocycles

Here we provide new experimental results on multicomponent reactions of amines with aldehydes and H₂S in the directed synthesis of functionally-substituted 1,3-thiazetidines, 1,3,5-dithiazinanes, 1,3,5-thiadiazinanes, 1,5-dithia-3,7-diazacyclooctanes, and thioaza macrocycles. X-ray analysis gave insight into the structure of the synthesized compounds. New kinds of multicomponent reactions (MCR) have been discovered and characterized.     

Synthesis and Fungicidal Activity of Bis-1,5,3-dithiazepanes and Crown-Like Macroheterocycles

Russian Journal of General Chemistry - An efficient method was developed for the synthesis of bis-1,5,3-dithiazepanes and crown-like N-cycloalkyl-1,11-dioxa-4,8-dithia-6-azacyclotridecanes by...     

Preparation of Cyclodextrin Nitrates

Nitration of α-, β-, and γ-cyclodextrins with nitric acid of various concentrations was studied. The nitration occurs similarly for all the three cyclodextrins studied. The influence of the reaction conditions on the degree of substitution of hydroxy groups in cyclodextrin by nitrate groups was examined. The composition and degree of substitution of the nitration products depend not only on the nitric acid concentration, but also on the molar ratio of HNO₃ to OH groups. The results obtained allow optimization of the procedure for preparing cyclodextrin nitrates with definite topology of substitution of cyclodextrin hydroxy groups.