Cathode fall characteristics in a dc atmospheric pressure glow discharge

Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the authors and the American Institute of Physics. This article appeared in the Journal of Applied Physics and may be found at: http://link.aip.org/link/?JAPIAU/94/5504/1Atmospheric pressure glow discharges are attractive for a wide range of material-processing applications largely due to their operation flexibility afforded by removal of the vacuum system. These relatively new atmospheric plasmas are nonequilibrium plasmas with gas temperature around 100 °C and electron temperature in the 1–10 eV range. Their appearance is characteristically diffuse and uniform, and their temporal features are repetitive and stable. Of the reported numerical studies of atmospheric glow discharges, most are based on the hydrodynamic approximation in which electrons are assumed to be in equilibrium with the local electric field. Spectroscopic and electrical measurements suggest however that the cathode fall region is fundamentally nonequilibrium. To this end we consider a hybrid model that treats the cathode fall region kinetically but retains a hydrodynamic description for the region between the thin cathode fall layer and the anode. Using this hybrid model, a helium discharge system excited at dc is studied numerically for a very wide current density range that spans from Townsend dark discharge, through normal glow discharge, to abnormal glow discharge. Numerical results confirm many distinct characteristics of glow discharges and compare well with that of low-pressure glow discharges. Generic relationships, such as that between the electric field and the current density, are also established and are in good agreement with experimental data. This hybrid model is simple and insightful as a theoretical tool for atmospheric pressure glow discharges

Половые различия в про- и антиоксидантной системах головного мозга в отдаленном постреанимационном периоде (экспериментальное исследование)

Objective: to study gender differences in the pro- and antioxidant systems of the brain in the late postresuscitative period after clinical death. Materials and methods. The brain tissue was studied for the resistance of membrane structures to free radical oxidation and the level of proteins with antioxidant activity in 40 adult albino rats of both sexes in the control and after experienced 12-minute cardiac arrest 4 months of the postresuscitative period. Results. There were gender differences in the level of protective proteins and in the resistance of brain membrane structures in the control and in the late postresuscitative periods. Furthermore, not only quantitative changes in the level of protective proteins, but also their spectrum alteration, were revealed in the postresuscitative period. Conclusion. Further investigations of gender-dependent mechanisms for the occurrence of postresuscitative diseases are needed to develop specific methods for its therapy and prevention. Key words: systemic circulatory arrest; cerebral cortex; free radical oxidation; the body’s protective systems: antioxidant defense enzymes, HSP70, heme oxygenase-1, peroxiredoxin.Цель исследования — изучение половых различий в уровне про- и антиоксидантных систем мозга в отдаленном постреанимационном периоде после клинической смерти. Материал и методы. У 40 взрослых белых крыс обоего пола в контроле и после перенесённой 12-мин остановки сердца через 4 месяца постреанимационного периода в ткани мозга исследовали резистентность мембранных структур к свободнорадикальному окислению и уровень белков с антиокси-дантной активностью. Результаты. Показаны половые различия в уровне защитных белков и резистентности мембранных структур мозга в контроле и на отдаленных сроках после реанимации. Кроме того, в постреанимационный период выявлены не только количественные сдвиги в уровне защитных белков, но и изменение их спектра. Заключение. Необходимы дальнейшие исследования зависимых от пола молекулярных механизмов развития постреанимационной болезни для разработки специфических методов ее терапии и профилактики. Ключевые слова: остановка системного кровообращения, кора головного мозга, свободнорадикальное окисление, защитные системы организма — ферменты антиоксидантной защиты, HSP70, гем-оксигеназа-1, пероксиредоксин

Gender Differences in the Pro- and Antioxidant Systems of the Brain in the Late Postresuscitative Period (an experimental study)

Objective: to study gender differences in the pro- and antioxidant systems of the brain in the late postresuscitative period after clinical death. Materials and methods. The brain tissue was studied for the resistance of membrane structures to free radical oxidation and the level of proteins with antioxidant activity in 40 adult albino rats of both sexes in the control and after experienced 12-minute cardiac arrest 4 months of the postresuscitative period. Results. There were gender differences in the level of protective proteins and in the resistance of brain membrane structures in the control and in the late postresuscitative periods. Furthermore, not only quantitative changes in the level of protective proteins, but also their spectrum alteration, were revealed in the postresuscitative period. Conclusion. Further investigations of gender-dependent mechanisms for the occurrence of postresuscitative diseases are needed to develop specific methods for its therapy and prevention. Key words: systemic circulatory arrest; cerebral cortex; free radical oxidation; the body’s protective systems: antioxidant defense enzymes, HSP70, heme oxygenase-1, peroxiredoxin

Language explication of the conceptualized meanings in ethno-cultural and socio-political aspects of discourse

The study of ethnical concept language representations in the South Ossetia discourse as the discourse of not recognized country is a new direction in political linguistics. The article is focused on revealing verbal representations and cognitive features of the ethno specific political concept 'фæндаг'/'road'as the only highway connecting the Republicof South Ossetia –the State of Alania with the outside world through the Republic of North Ossetia (Russia). Based on lexicographic sources, media materials, Internet blogs and data from the associative experiment conducted in three age groups, among teenagers and young people, people of the middle and older generation, the structure and content of this discursive formation were revealed.El estudio de las representaciones lingüísticas de conceptos étnicos en el discurso de Osetia del Sur como el discurso de unpaís no reconocido es una nueva dirección en lingüística política. El artículo se centra en revelar representaciones verbales y características cognitivas del concepto político etno específico 'фæндаг' / 'road' como la única carretera que conecta la República de Osetia del Sur, el Estado de Alania con el mundo exterior a través de la República de Osetia del Norte (Rusia). Con base en fuentes lexicográficas, materiales de medios, blogs de Internet y datos del experimento asociativo realizado en tres grupos de edad, entre adolescentes y jóvenes, personas de generación media y mayor, se reveló la estructura y el contenido de esta formación discursiva

Observation of the strong anomalous absorption of the X-mode pump in a plasma filament due to the two-plasmon decay

The effect of strong anomalous absorption of the X-mode pump wave associated with the two-upper-hybrid-plasmon parametric decay is observed in a specially performed model experiment in a laboratory plasma. The strong microwave absorption takes place at the maximal plasma density higher than the upper-hybrid resonance value for the frequency equal to half of the pump frequency value. Its efficiency is determined at the level of 80% in the initial stage of the parametric decay instability saturation and 45% in the following steady state. The theoretical model of the two-upper-hybrid-plasmon decay in strongly inhomogeneous plasma is developed. The localization, threshold and growth rate of the instability are determined in agreement with experimental observations