Simulations of the Formation of Nitrogen Oxides at the Cooling Stage of a Subthreshold Microwave Discharge in Air with Admixtures of Methane

Plasma Physics Reports - Studies of the composition of the products of chemical reactions in the afterglow of a new type of atmospheric discharge, the microwave self-non-self-sustained discharge in...     

Characteristics of a Subthreshold Microwave Discharge in a Wave Beam in Air and the Efficiency of the Plasma-Chemical Reactor

Plasma Physics Reports - An analysis of a set of experiments on studying subthreshold microwave self/non-self-sustained (SNSS) discharges made it possible to estimate the volume of the active zone...     

Plasmoid Generation behind the Front of a Subthreshold Discharge in Air under the Self-Action of a Microwave Beam

Plasma Physics Reports - Frames of a subthreshold microwave SNSS discharge were obtained in experiments. They showed that, behind the front of the head plasmoid with a fine-cell glow structure,...     

Discharge in a Subthreshold Microwave Beam as an Unusual Type of Ionization Wave

Plasma Physics Reports - Ionization−overheating instability of a non-self-sustained discharge in air in a subthreshold microwave field creates a self-sustained discharge with a fine cellular...     

Subthreshold Discharge in a Microwave Beam as the Basis of a Plasmachemical Reactor for Cleaning Urban Air from Excess Hydrogen Sulfide

Plasma Physics Reports - The subthreshold self-non-self-sustained discharge in air was studied as the basis of the system for cleaning urban air from ecologically harmful admixtures. A cycle of...     

Discharge in a Subthreshold Microwave Beam as an Effective Means for Mercaptan Decomposition

Plasma Physics Reports - A subthreshold microwave discharge in atmospheric-pressure air is used to process mixtures of mercaptans (thiols) with air and with air and methane. It is found that, at...     

A Subthreshold High-Pressure Discharge Excited by a Microwave Beam: Physical Basics and Applications

A new form of discharge excited by a microwave beam in a high-pressure (up to atmospheric and higher) gas in free space and in a closed chamber is discussed. For the first time, the discharge was implemented by means of a gyrotron with a pulse power of 200 ≤ P ≤ 600 kW, a pulse duration of 0.5 ≤ τ ≤ 20 ms, and a wavelength of λ = 0.4 cm. Under deeply subthreshold conditions in atmospheric-pressure air, a plasma column with a length of L = 50 cm was generated by a microwave beam formed with the help of a quasi-optical transmission line. With the use of the MIG-3 gyrotron complex with the above parameters, generation of a plasma column with a length of several meters is possible in principle. The parameters and structure of the formation of the plasma investigated make it possible to class it as a self-non-self-sustained (SNSS) discharge, discovered and described for the first time at the Prokhorov General Physics Institute, Russian Academy of Sciences. One of the important applications of this type of discharge is plasmachemical cleaning of the urban air environment of hazardous contaminants.     

Inhibition of Growth in Tomato by Air Polluted with Nitrogen Oxides

Air polluted with parts 10_–8concentrations of NO and NO₂significantly reduced the rate of growth of tomato seedlings.These two pollutants are known to occur in glasshouse atmos-Dhcresenriched with CO² from propane or kerosene burners. The inhibitionof growth would be sufficient to reduce, or even nullity, thebenefits of CO₂enrichments under conditions of low light intensityin winter.     

Dynamics of Focused Pulsed Microwave Discharge in Air

Plasma Physics Reports - The formation dynamics of the parameters of a microwave discharge in air localized at electric field maxima created by a specially developed focusing system is investigated...     

Propagation of Microwave Discharge Sustained by Surface Wave in Quartz Tube Filled with Low-Pressure Air

Plasma Physics Reports - Propagation was studied of the ionization front of the gas discharge sustained by the microwave surface wave in a quartz tube filled with low-pressure air. In a wide...     

Effect of Nitrogen Additive on Inhomogeneous Microwave Discharge in Hydrogen at Reduced Pressures

Plasma Physics Reports - The effect of a small nitrogen additive on a microwave discharge in hydrogen ignited near the antenna at a pressure of 1 Torr was studied by emission spectroscopy and...     

Characteristics of a Pulse-Periodic Corona Discharge in Atmospheric Air

Pulse-periodic corona discharge in atmospheric air excited by applying a voltage pulse with a subnanosecond or microsecond rise time to a point electrode is studied experimentally. It is shown that, at a voltage rise rate of dU/dt ~10¹⁴ V/s, positive and negative ball-shaped streamers with a front velocity of ≥2 mm/ns form near the point electrode. As dU/dt is reduced to 10¹⁰?10¹¹ V/s, the streamer shape changes and becomes close to cylindrical. The propagation velocity of cylindrical streamers is found to be ~0.1 mm/ns at dU/dt ~ 2 × 10¹⁰ V/s. It is shown that the propagation direction of a cylindrical streamer can be changed by tilting the point electrode, on the axis of which the electric field strength reaches its maximum value. It is established that, for the negative polarity of the point electrode and a microsecond rise time of the voltage pulse, a higher voltage is required to form a cylindrical streamer than for the positive polarity of the point electrode.     

Study of Gallium Arsenide Etching in a DC Discharge in Low-Pressure HCl-Containing Mixtures

Halogen-containing plasmas are often used to form topological structures on semiconductor surfaces; therefore, spectral monitoring of the etching process is an important diagnostic tool in modern electronics. In this work, the emission spectra of gas discharges in mixtures of hydrogen chloride with argon, chlorine, and hydrogen in the presence of a semiconducting gallium arsenide plate were studied. Spectral lines and bands of the GaAs etching products appropriate for monitoring the etching rate were determined. It is shown that the emission intensity of the etching products is proportional to the GaAs etching rate in plasmas of HCl mixtures with Ar and Cl₂, which makes it possible to monitor the etching process in real time by means of spectral methods.     

A Grand Canonical Monte-Carlo Study of Lennard-Jones Mixtures in Slit Pores; 2: Mixtures of Two Centre Ethane with Methane

Abstract

Mixtures of ethane and methane in a slit micropore were simulated using the Grand Canonical Monte Carlo technique. Ethane was modelled as two Lennard-Jones sites while methane was modelled as a single Lennard-Jones site. The elongated shape of ethane was found to strongly influence the calculated adsorption selectivity, and important qualitative differences were noted relative to an earlier GCMC study (Cracknell et al., Molec Phys Vol 80, pp 885–897, 1993) in which ethane was modelled as a spherical Lennard-Jones particle. The influence of ethane bond length on methane-ethane selectivity was studied further by conducting simulations with the ethane C[sbnd]C distance 28% and then 70% longer than its actual length; the hindrance of rotation by confinement in the micropore was found to cause a significant decrease in selectivity. The Ideal Adsorbed Solution Theory was found to predict the selectivities with a reasonable degree of accuracy given simulated single component data as input.     

Charging of Macroparticles in a Corona Discharge in an Air Flow

The charging of Al₂O₃ macroparticles with dimensions ranging from 20 to 40 μm in a gas flow passing through a multielectrode corona discharge is investigated. The corona discharge is produced by a system of wire electrodes arranged across the gas flow. The particle charge and mass are measured using a linear electrodynamic trap. For a corona voltage of 18 kV, the average charge-to-mass ratio is found to be 1.69 × 10¹³e/g for particles charged in the positive corona and 1.35 × 10¹³e/g for particles charged in the negative corona.     

Self-Action of a Gaussian Beam of Microwaves in the Subthreshold Field Generated by the Waves in Air

Plasma Physics Reports - A microwave beam (wavelength 4 mm, power 150–300 kW) generates an ionization wave in air in the subthreshold field in the shape of a conglomerate of thread-like...     

Ignition Conditions for a Self-Pulsing Microhollow Cathode Discharge in Air

Plasma Physics Reports - This work is devoted to the study of the electrical characteristics of a microhollow cathode discharge in air at atmospheric pressure. It was found experimentally that the...     

Formation of Wide Streamers during a Subnanosecond Discharge in Atmospheric-Pressure Air

Results are presented from experimental and computational studies of a subnanosecond breakdown of atmospheric-pressure air in a nonuniform electric field. It is shown that the ionization waves (streamers) formed in the prebreakdown stage have a nearly spherical or conical shape. The diameter of the streamer in its widest part is found to increase with increasing voltage and discharge gap length. For a rise time of the voltage pulse of ≈0.5 ns and its amplitude of ≈250 kV, streamers about 8 cm in diameter were observed in a 7-cm-long gap.     

Time-Resolved Optical Diagnostics of the Microwave Discharge in Liquid Hydrocarbons with Argon Bubbling

Plasma Physics Reports - The methods of emission spectroscopy, shadow photography, and integral radiation of a discharge with time resolution are used to study the initial stages of the development...     

Nitrogen Relationships of Vigna mungo in Pure Stands and in Celosia argentea Mixtures

Dynamics of the nitrogen relationships of Vigna mungo in pureand in mixed stands with Celosia argentea, a common weed ofleguminous crops in certain regions of India, were investigated.The weed significantly depressed nodulation and reduced thedry matter and nitrogen yield of the legume which was lowestat the highest density of the weed. A significant amount ofnitrogen transfer occurred from the legume in the weed mixtureswhich appeared to be taken up by the weed plants. Therefore,weed plants benefited from their association with the legumeby accumulating more dry matter and nitrogen in the legume mixtures.The possible competitive or biochemical interference of theweed with nitrogen relationships of the legume in mixtures isdiscussed. Vigna mungo, Celosia argentea, pure stands, mixed stands, total nitrogen, interference