Abstract: In an electrochemical sensor, a gas analyzing electrochemical cell is implanted directly on a substrate wafer. The entire wafer is coated with enamel layers except at the places needed for the electrical connections. A fixing part fixes the sensor in a housing in such a way that the electrochemical cell is inside the housing which contains the gas to be analyzed. This fixing part provides imperviousness and prevents the gases from reaching the electrical connections.

Abstract: A device comprising an inhomogeneous solid electrolyte of doped materials which are exclusive conductors for a predetermined chemical species. The electrolyte has a first region and a second surface region, the thickness of which is usually less than 400 .ANG.. In a first alternative embodiment, the second region is formed by increasing the doping percentage of the material constituting the first region. In a second alternative embodiment, the second region is formed by depositing a thin film of doped material chosen so as to ensure that the work function to be provided by the predetermined chemical species is of lower value than in the case of the doped material constituting the first region.

Abstract: A method for making a microcavity in an enamel layer is disclosed. For this purpose, a layer of a carbon-based material with the dimensions of the microcavity to be obtained is provided. This layer is coated with an enamel except in a limited zone. The unit is heated to high temperature so as to cause combustion of the carbon-based material. The combustion gases escape through the reduced zone.

Abstract: A method for making a microcavity in an enamel layer is disclosed. For this purpose, a layer of a carbon-based material with the dimensions of the microcavity to be obtained is provided. This layer is coated with an enamel except in a limited zone. The unit is heated to high temperature so as to cause combustion of the carbon-based material. The combustion gases escape through the reduced zone.

Abstract: Electrochemical sensor for the concentrations of species in a fluid mixture comprising a measuring cell of the type having a partial pressure internal reference electrode incorporating a catalysis region in which the gaseous mixture is brought into thermodynamic equilibrium and functioning according to the so-called "assay" process, so that only a small quantity of the gaseous mixture to be analyzed is admitted into the sensor. It also comprises a supplementary cell functioning as an ionic pump, so as to continuously modify the composition of the gaseous mixture admitted into the sensor under the control of a regulatable electric current.

Abstract: A device for inserting a sensor into the exhaust conduits of an internal combustion engine, wherein the support of the sensor is formed by the sealing element of the assembly gaskets of these exhaust conduits. In accordance with a first variation the sensor is inserted by means of the gasket located between the manifold and the exhaust pipe, and in accordance with a second variation the sensor is inserted by means of the gasket located between the cylinder head and the exhaust manifold. This gasket may comprise several sensors, one per exhaust port. The sensor to be inserted may in particular be of the electrochemical collector type comprising a measuring cell of the concentration-stack type.

Abstract: An electrochemical sensor for measuring relative concentrations of reactive species in a fluid mixture with a first catalytic enclosure for bringing the fluid mixture into thermodynamic equilibrium, and a second enclosure having an electrochemical cell which is responsive to an excess of one of the reactive species with respect to stoichiometry of the reaction. Additional structure for selectively impeding the transfer of species of the fluid mixture to be analyzed are located upstream of or combined with the first enclosure and serve to modify the ratio of relative concentrations of the reactive species of the fluid mixture in predetermined proportions.

Abstract: The electrochemical sensor for measuring concentrations of species in a fluid mixture is of the type comprising a partial-pressure internal reference electrode constituted by a system in which a metal is combined with an oxide of said metal. One face of the reference electrode is in contact with a solid electrolyte. An inert protective coating deposited on all the other faces of the electrode is impervious to the species which are present in the fluid mixture.

Abstract: The sensor comprises an electrochemical measuring cell having a flat structure and constituted by two electrodes in contact with a solid electrolyte. One electrode which is formed of catalytic material has an extension of predetermined length in at least one direction parallel to the plane of the cell in order to be placed in contact with the fluid mixture and to bring it into thermodynamic equilibrium prior to analysis.

Abstract: In a process for producing a surface compound between a substrate and a reactive species a thin layer permeable to the species in question is deposited on the substrate. A particularly interesting case is the oxidation of a substrate of gallium arsenide, the thin layer being made from zirconia doped with lime.

Abstract: A process designed for manufacturing an opto-electronic device comprising at least one light-guide integrated in a substrate with a control electrode constituted by a metallic band covering the light-guide and deposited onto the substrate, and an earth-plane integrated in the bottom of the substrate. The process comprises a preliminary step wherein the light-guide is created by doping the substrate for example in a channel adjacent to the upper side of the substrate. In the first step the material of the substrate (e.g. monocrystalline lithium niobate) is chemically reduced by hydrogen for rendering the whole substrate electrically conductive (and consequently opaque). After a second step of partial protective masking, a third step takes place wherein the upper part of the substrate is re-oxidized for restoring a transparent layer comprising the light-guide - the latter characterized by a higher refractive index - and an insulating medium in the upper part of the substrate.

Abstract: A means for producing electricity from an electrochemical reaction as well as for storing and recovering electrical energy, which utilize electrochemical reactions. The basic galvanic cell comprises a first solid non-porous body capable of storing large quantities of an ionizable species (this is the case with a metal hydride and hydrogen) the ionized species (H.sup.+ ions) migrating through a thin-film solid electrolyte (alumina) towards a second body (oxygen or atmospheric air) where the electrochemical reaction takes place (and the water produced is easily eliminated). The internal resistance of the cell is low because the electrolyte is in thin-film form. The technology of thin-film deposition is possible because the first body is a non-porous solid.

Abstract: A method aiming at imparting to the amorphous silicon properties which are compatible with the possibility of modifying by doping or field effect the position of the Fermi level in the volume of the amorphous silicon, a prime requirement for the operation of semiconductor devices. The method comprises a first step of depositing a layer of amorphous silicon onto a substrate under conditions ensuring the purity of the deposit obtained, then a second step wherein the deposit is subjected to a heat treatment consisting in maintaining the deposit in the atmosphere of a plasma containing atomic hydrogen for saturating the existing broken chemical bonds responsible for a parasitic electric conductivity.

Abstract: The device is based on the use of amorphous thin layers having a thickness of the order of 1000 Angstrom units and a cellular structure on the same scale as the distances between atoms, the structure being homogeneous and isotropic inside the layer. The structure is made of substances which are physically and chemically inert towards the substances to be separated. The cellular structure is due to the incorporation in the layer of elementary particles acting as network dilators or network modifiers.