Enhancement of CO2 conversion by counterflow gas quenching of the post-discharge region in microwave plasma sustained by gyrotron radiation

A threefold increase in the CO2 conversion and energy efficiency due to the cooling of the post-discharge region by the counter gas flow has been achieved in the plasma of an atmospheric pressure discharge supported by microwave radiation of a gyrotron with a frequency of 24 GHz in a carbon dioxide gas flow. The role of convective heat transfer in the process of gas mixture cooling in the post-discharge region has been experimentally demonstrated. At nitrogen quench gas flow of 4.5 l/min, the CO2 conversion was 23.8 % and energy efficiency was 19.7 %. The possibility of using the flow of cooled gas mixture (CO2,CO,O2) taken from the reactor as quenching gas has been experimentally demonstrated, which made it possible to achieve a CO2 conversion degree of 23.4 % and to eliminate the problem of dilution of reaction products by third-party gases. Based on numerical modeling, it is shown that the increase in the conversion degree upon the destruction of the plasma torch structure is due to the increase in heat exchange with the surrounding atmosphere, and the efficiency of this destruction is determined by the velocity and density of quenching gas.Comment: 20 pages, 14 pages, submitted to the Journal of Energy Chemistry 28.11.202

Elaboration of a Novel Design Pirani Pressure Sensor for High Dynamic Range Operation and Fast Response Time

AbstractWe report a novel design for realizing Pirani sensor with a working range from a 1kPa up to pressure over than atmospheric one. The sensor is specifically designed to achieve high sensitivity, fast response time and high robustness. The proof of concept is composed of four metallic resistors interconnected to form a Wheatstone bridge. Two of them act simultaneously as the heating and sensing elements and the two others are used as a temperature reference. The heating element consists of a metallic wire of platinum Pt (3μm width, 1mm length) maintained on each lateral side by periodic silicon oxide SiO2 micro-bridges. The sensor design, fabrication technologies, electrical characterizations and voltage-pressure responses are described and shown. A future perspective is given, which describe the extension of this concept to elastic wave transduction of pressure using a combination of heater element and thin plate elastic waveguide

Hybrid subterahertz atmospheric pressure plasmatron for plasma chemical applications

This paper presents the results of an experimental study of a new hybrid plasmatron scheme, which was used to realize a gas discharge at atmospheric pressure supported by continuous focused submillimeter radiation with a frequency of 263 GHz. The implemented design allowed organizing a self-consistent interaction between submillimeter radiation and the supercritical plasma in a localized area both in terms of gas flow and electrodynamic. It is experimentally shown that the gas discharge absorbs up to 80% of the introduced submillimeter radiation power. The hybrid subterahertz plasmatron as an effective reactor for non-equilibrium plasma chemical processes was tested for the atmospheric nitrogen fixation

Primary accumulation in the Soviet transition

The Soviet background to the idea of primary socialist accumulation is presented. The mobilisation of labour power and of products into public sector investment from outside are shown to have been the two original forms of the concept. In Soviet primary accumulation the mobilisation of labour power was apparently more decisive than the mobilisation of products. The primary accumulation process had both intended and unintended results. Intended results included bringing most of the economy into the public sector, and industrialisation of the economy as a whole. Unintended results included substantial economic losses, and the proliferation of coercive institutions damaging to attainment of the ultimate goal - the building of a communist society

ЗАВИСИМОСТЬ ДЕФОРМАЦИОННОГО СОСТОЯНИЯ ПЛЕНОК GaAs НА ВИЦИНАЛЬНЫХ ПОДЛОЖКАХ Si(001) ОТ СПОСОБА ФОРМИРОВАНИЯ ПЕРВЫХ МОНОСЛОЕВ ПРОСЛОЙКИ GaP

A significant dependence of the strain state of GaAs film lattice grown by molecular−beam epitaxy (MBE) on the nucleation method of early GaP buffer layers (50 nm) on the vicinal substrate Si(001) 4° around the <011> axis was discovered. GaP growth started layer−by−layer with a gallium or a phosphorus sublayer. If GaP nucleated with a gallium sublayer, the GaAs film has a significant lattice rotation around the <011> axis. If the buffer starts forming with a phosphorus layer the GaAs film evidently rotates around the <001> axis. The film relaxation degree ex- ceeds 100%, and the film is in a laterally strained state. Analysis was carried out using the triclinic distortion model. A reciprocal space scattering map was obtained using X−ray diffraction in a three−axis low resolution setup. The map clearly shows that the GaAs film lattice is rotated.Выявлена существенная зависимость деформационного состояния кристаллической решетки пленок GaAs, выращенных методом молекулярнолучевой эпитаксии от способа зарождения первых слоев прослойки GaP (50 нм) на вицинальной подложке Si(001) 4° вокруг оси <011>. Рост GaP начинался послойно с галлиевого или фосфорного подслоя. Установлено, что в случае зарождения GaP с галлия, пленка GaAs имеет значительный поворот кристаллической решетки вокруг направления <011>. При фор- мировании прослойки с фосфорного подслоя заметен поворот пленки GaAs вокруг <001>. Степень релаксации пленки составляет более 100 %, она находится в латерально растянутом состоянии. Анализ проведен с использованием модели триклинных искажений. Представлена карта рассеяния в обратном пространстве, полученная с помощью рентгеновской дифрактометрии в трехосевой схеме малого разрешения. На карте явно виден факт поворота кристаллической решетки пленки GaAs.

Optical properties of graphane in infrared range

The theory of optical effects in hydrogenated graphene (graphane) in terahertz and infrared range is developed, including the analysis of complex conductivity, reflection coefficient for graphane on a substrate and dispersion of surface plasmon-polaritons. The calculations are based on quite simple analytical approximation of graphane band structure in the vicinity of Gamma-point and on the modified model of quantum coherence relaxation. Comparison of the obtained theoretical results with corresponding experimental data can be used both for the determination of graphane characteristics (Fermi level, relaxation rate etc.) and for the investigation of potential applications of this material in the design of new optical elements