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This paper presents a homogeneous study of xenon dielectric barrier discharge (DBD). The model, including plasma chemistry, electrical circuit, and Boltzmann equation modules, investigates the electrical and physical characteristics of high-pressure DBDs. The model is applied in the case of a sinusoidal voltage at period frequency of 50 kHz and gas pressure of 400 torr. First, we have analyzed the temporal evolutions of the plasma voltage, the current density and the species concentrations. Then, the physical model validity is checked by comparing the model results with a theoretical work. The effect of the kinetic scheme on the electrical parameters, the species concentration, and the total lamp efficiency are also investigated and discussed.

The distribution of the gas temperature, due to the heat Joule effect in dielectric barrier discharge and for different rare gases (Ar, Ne, Xe, and Kr), was investigated using a 1-D time-dependent fluid model. The model is based on the resolution of the transport equation of the electrons and the ions coupled with the Poisson's equation for a parallel-plate dielectric barrier discharge reactor. To consider of gas heating due to ions and electrons, we solve the heat transport equation along of the discharge gap. The results show an increasing of the gas temperature in front of the dielectrics due to heavy ions for different noble gases used (Ar, Ne, Xe, and Kr). The effect of the applied voltage, the gas pressure as well as the secondary electron emission of MgO bombardment by rare gas ions on the gas temperature is also analyzed.

Des méthodes relativement récentes, comme l’échange d’ions et l’extraction liquide-liquide, ont été largement utilisées pour séparer des métaux à l’état de traces. Pour ceux qui présentent notamment des propriétés analogues, la complexation par des agents chélatants s’avère nécessaire. Du fait de leur grande stabilité thermique et de la diversité des groupements fonctionnels des produits commerciaux disponibles, les résines ont été d’une grande utilité en analyse et dans l’industrie. Cette étude a trait à la rétention de métaux comme le cadmium et le zinc sur les résines acides Amberlite IRC-50, Dowex-50 X8 et Permutit C‑67. Les études en flacon ont mis en évidence une grande affinité de ces éléments pour les résines utilisées, et que l’équilibre est atteint rapidement (30 à 60 min). Les ions Zn2+ et Cd2+ n’utilisaient au maximum que 88 à 91 % de capacité totale des résines étudiées. Le traitement des résultats pour les faibles concentrations a montré que les isothermes sont du type Langmuir comme ceux obtenus par ailleurs sur des échangeurs minéraux.

Dielectric barrier discharges (DBDs) are a promising technology for high-intensity sources of specific ultraviolet (UV) and vacuum ultraviolet (VUV) radiation. In this work, the microdischarge dynamics in DBDs for Ne–Xe mixtures under the close conditions of excimer lamp working has been investigated. The computer model including the cathode fall, the positive column and the dielectric is composed of two coupled sub-models. The first submodel describes the electrical properties of the discharge and is based on a fluid, two-moments description of electron and ion transport coupled with Poisson's equation during the discharge pulse. The second submodel, based on three main modules: a plasma chemistry module, a circuit module and a Boltzmann equation module, with source terms deduced from the electric model, describes the time variations of charged and excited species concentrations and the UV photon emission. The use of the present description allows a good resolution near the sheath at high pressure and it predicts correctly the waveform of the discharge behaviour. The effects of operation voltage, dielectric capacitance, gas mixture composition, gas pressure, as well as the secondary electron emission by ion at the cathode on the discharge characteristics and the 173 nm photon generation have been investigated and discussed.