Abstract: Provided is a device for the microwave-sustained plasma treatment of gases, which comprises a hollow structure forming a waveguide intended to be connected to a microwave generator, and means for making the gas to be treated flow through the said structure in a region in which the amplitude of the electric field associated with the incident wave is high. The means for making the gas flow comprise a plasma torch for producing a plasma in the gas. The torch comprises an injector made of an electrically conducting material mounted on a first large face of the said structure and extending so as to project through an orifice made in a second large face opposite the said first large face. A gap for passage of the incident waves lies around the injector.

Abstract: Provided is a novel method of and system for recovering and recirculating a deuterium-containing gas. According to the inventive method, a deuterium-containing feed gas is introduced into a chamber. An exhaust gas containing deuterium is removed from the chamber. The deuterium concentration of the exhaust gas is adjusted to a predetermined value, thereby producing a concentration-adjusted gas stream. Finally, the concentration-adjusted gas stream is introduced into the chamber as the deuterium-containing feed gas. The invention makes the use of deuterium, for example, in the mass production of semiconductor devices, commercially feasible.

Abstract: The invention concerns a device for exciting a gas comprising a hollow structure (24) forming a waveguide to be connected to a microwave generator and means for circulating a gas through the structure. The gas circulating means comprise an assembly of at least two hollow tubes (46, 48) made of dielectric material respectively passing through said structure (24) in the zones wherein the amplitude of the electric field associated with the incident wave is substantially the same.

Abstract: An apparatus for the treatment of perfluorinated and/or hydrofluorocarbon gases, for the purpose of destroying them, is provided. The apparatus includes at least one high-frequency surface-wave exciter which produces surface waves, a waveguide designed to guide the surface waves produced by the at least one wave exciter to at least one hollow dielectric tube for (i) creating, when supplied with a carrier gas an atmospheric-pressure plasma and (ii) for dissociating the molecules of the perfluorinated and/or hydrofluorocarbon gases within the plasma in order to form reactive compounds, and at least one treatment unit for the reactive fluorinated compounds which is arranged on an exit side of a corresponding hollow dielectric tube.

Abstract: Device for exciting a gas comprising a hollow structure forming a waveguide, made of an electrically conductive material, connected to a microwave generator and including a passage for a hollow dielectric tube adapted for flow of the gas to be excited, the hollow structure further including a wave-concentrating region designed to concentrate microwave radiation produced by the generator onto the tube, during operation of the device, for the purpose of producing a surface wave plasma in the gas, at least one electromagnetic screening sleeve made of a conductive material, fastened to the hollow structure and extending along the extension of the passage so as to surround the hollow tube.

Abstract: The invention relates to a storage box for an object that is to be protected from physicochemical contamination. The storage box is intended to have low weight, good mechanical strength, a good electrical condition, with a low degassing rate in time with prevention of diffusion of gasses from the external atmosphere into the interior of the box. The inner and/or outer surface of the box's walls are coated with at least one protective layer. The box may be used to store silicon wafers.

Abstract: Provided are a process and apparatus for purifying a gas. In accordance with the process, the gas to be purified flows through a hollow dielectric tube. An electric field is created in the gas to be purified by a traveling electromagnetic wave which travels in the dielectric tube and creates, in the gas, an atmospheric-pressure plasma which is not in local thermodynamic equilibrium, for the purpose of dissociating impurities in the gas to form reactive compounds. The formed reactive compounds are reacted with a corresponding reactive material for eliminating the reactive compounds from the gas to be purified.

Abstract: Provided is a process for purfying a gas. In the process, the gas to be purified flows through a hollow dielectric tube. An electric field in the gas to be purified is created by a traveling electromagnetic wave which travels in the dielectric tube and is suitable for creating, in the gas, an atmospheric-pressure plasma which is not in local thermodynamic equilibrium, for the purpose of dissociating impurities in the gas in order to form reactive compounds. The formed reactive compounds are reacted with a corresponding reactive material for eliminating the reactive compounds from the gas to be purified.

Abstract: A process for treating perfluorinated and/or hydrofluorocarbon gases, comprising the steps ofcreating an atmospheric-pressure gas plasma in at least one hollow dielectric tube;making the gases to be treated flow through the at least one dielectric tube in contact with the plasma for the purpose of dissociating molecules of the gases into reactive compounds; andreacting the reactive compounds with a corresponding reactive element for the purpose of destroying them.

Abstract: The invention concerns the preparation of an optical structure. On a polymeric substrate there is first provided a surface activation, and the deposit of a layer of SiO.sub.2, 2000 .ANG. thick after which there is a deposit of a plurality of functional layers and finally a deposit of SiO.sub.2, 3 microns thick followed by a deposit of Si.sub.3 N.sub.4 /SiO.sub.x N.sub.y 3 microns thick, the latter being produced under radio-frequency polarization. The thus obtained optical structure has properties of adhesiveness, resistance to abrasion and to thermal impacts.

Abstract: Multilayer coating for polycarbonate substrate used as glass substitute essentially consisting of silicon, carbon, nitrogen, oxygen and hydrogen, characterized by a first anti-ultra-violet layer consisting of silicon, oxygen and/or nitrogen, carbon and hydrogen, according to formula:SiCx.sub.1 Oz.sub.1 Ht.sub.1,where x.sub.1 +z.sub.1 +t.sub.1 is between 1,2 and 1,5SiCx.sub.1 Ny.sub.1 Ht.sub.1,where x.sub.1 +y.sub.1 +t.sub.1 is between 1,2 and 1,5SiCx.sub.1 Ny.sub.1 Oz.sub.1 Ht.sub.1,where x.sub.1 +y.sub.1 +z.sub.1 +t.sub.1 is between 1,2 and 1,4and t.sub.1 is always between 0,1 and 0,7; x.sub.1 before y.sub.1 and/or z.sub.1 is small, so that the limit of optical absorption is concentrated at about 350 nm; the second transparent hard layer consists of silicon, oxygen, nitrogen, carbon and hydrogen, of formula SiCx.sub.2 Ny.sub.2 Oz.sub.2 Ht.sub.2, where, in particular:either y.sub.2 =0, z.sub.2 is between 1,7 and 2,0, t.sub.2 is between 0,1 and 0,7, x.sub.2 before z.sub.2 is small;or y.sub.

Abstract: Multilayer coating for polycarbonate substrate used as a glass substitute, consisting essentially of silica, oxygen and nitrogen, and hydrogen according to the formulaSiO.sub.2 :HSiN.sub.y :Hcharacterized by a composite structure of the coating combining an interferential system with a reflectance window extending over a narrow band of wavelengths from the lower edge of the visible region toward wavelengths shorter than ultraviolet on the one hand, and an absorptive system of which the band of wavelengths of transmission from the absorptive region to the transparent region is located in the reflectance window of the interferential system. There is thus provided a coating with an abrupt variation of coefficient of transmission. The multilayer coating is particularly useful as a glass substitute for automobile headlight lenses.