Abstract: A cathode for an electrolyser. It comprises porous conductive material which includes sintered nickel impregnated with a catalyst, characterized in that said catalyst is a molybdate of nickel or iron or mixtures thereof. The invention is used for manufacturing hydrogen by electrolysing an aqueous alkaline solution.

Abstract: A method of plugging the ends of selected ducts (5) in a ceramic structure (1). A paste (8, 9) is prepared from a powder and a liquid. The powder comprises a glass whose coefficient of expansion is close to that of the ceramic structure. The liquid comprises a solvent, a plasticizer and an additive which reduces the adherence of the paste to a paste applying tool (6, 7). The tool is used to push paste into the ends of the selected ducts and the ceramic structure is subjected to heat treatment to ensure that the paste adheres to the walls of the ducts and then becomes solid.

Abstract: The invention relates to a fibre-to-fibre connector including a component for joining it to an optical fibre cable. A flat connector with two parallel layers of fibres (18) is easily connected to a round multi-fibre optical cable (12) due to the fact that it includes a separable joining component (R) provided with guide means (G5,G6) for guiding with respect to the rest of the connector (C), said component including a distributor (100,101,102) which forms two distributor channels which progressively bring the set of fibres (18) which leave the cable up to the disposition in two layers. Application to telecommunications.

Abstract: An outer casing (1) and an inner mandrel (2), both of which are cylindrical and are substantially coaxial, with powder (3) for manufacturing the tubular parts (11) filling the space which lies between them, contain a stationary distance piece (5) disposed against a shoulder (4) formed in the upper portion of the mandrel (2) and around the upper portion. A cover (6) also is provided around the upper portion and bears firstly against the upper end of the stationary distance piece (5) and secondly against the end of the casing (1), the cover (6) being hollowed out so as to provide an annular space (7) around the stationary distance piece (5), a moving distance piece (8) being disposed in the space (7) and bearing against the surface of the powder (3) so that during isostatic compression, the upper end of the moulded part (11) can extend into the space (7) while driving the moving distance piece (8).

Abstract: An electric cell with a non-aqueous electrolyte. The cell includes a positive electrode whose active material is suitable for inserting the negative active material dynamically, a negative electrode whose active material includes at least one alkali metal, and an electrolyte, wherein said positive electrode includes at least one compound whose general formula is MX.sub.4 R.sub.n T.sub.p, where M represents an element chosen from among silicon, germanium, tin and lead, X represents sulphur, selenium or tellurium, R and T represent an element chosen from among copper, silver, manganese, iron, cobalt and nickel, n being greater than or equal to 0 and less than or equal to 4, p being greater than or equal to 0 and less than or equal to 2. The invention is used in connection with button type electric cells.

Abstract: The invention relates to a gas laser assembly which is capable of emitting stabilized frequency pulse radiation. Said arrangement includes a first continuous gas laser generator and a second pulse gas laser generator, an optical system (19, 56, 20) to inject the continuous beam (18) emitted by the first laser generator via the optical cavity (8-9) of the second laser generator and a servo control circuit (21,23,24,25) acting in synchronism on the length of the cavities (5-6,8-9) of the first and second lasers, so as to keep these lengths equal at a fixed value. Application to range finders operating by heterodyne detection.

Abstract: Lead accumulator which comprises a plurality of elements each consisting of a negative plate, a positive plate and separating means intercalated between these plates, the said separating means comprising a first and a second microporous separator, between which spacers define channels, characterized in that the thickness of the channels (11) is between 0.5 mm and 2 mm and in that the width of the channels (11) is between 2 mm and 10 mm.Particularly valuable application in traction batteries.

Abstract: In a method of regulating the temperature of a system in which exothermic type reactions take place at temperatures of several hundreds of degrees and which are followed by stoppage periods, the system (1) is put in contact with a first substance (4) whose boiling temperature (T2) is close to the required temperature (T) of the system, and heat which results from the exothermic reactions is used to boil the first substance (4). Thereafter heat which comes from the condensation of the vapor evolved by said boiling is used to heat a second substance (5) to its melting point (T1), the second substance (5) being chosen so that it melts at a temperature close to but lower than the boiling temperature (T2) of the first substance (4). In operation the second substance (5) is kept at a temperature which is substantially constant and a little higher than its melting point (T1) until the end of a period of exothermic reaction.

Abstract: A tubular ceramic part is formed with a shoulder at an open end of the part, the tubular part is inserted in an opening provided in a horizontal plate which is disposed inside a sintering chamber so that the part is kept suspended in the chamber by means of the shoulder which rests against the edge of the opening, a shouldered cylindrical plug is inserted into the open end of the tubular part until the shoulder of the plug bears against the end of the tubular part, and the chamber is brought to sintering temperature. The invention is implemented to produce solid beta sodium alumina electrolyte tubes for sodium-sulphur electric cells.

Abstract: This system includes optical fibers (21,26,49,51) which connect subscriber sets (p,n) to an optical interconnection center (59). An optical frequency F.sub.p and a modulation frequency f.sub.p are ascribed to each subscriber p, these frequencies being specific to the subscriber. The set of each subscriber p includes a laser (19) which delivers a wave (22) of frequency F.sub.p and means (9, 12 to 18) to modulate the amplitude of this wave at the frequency f.sub.n ascribed to the subscriber n with whom he wishes to communicate.

Abstract: The photovoltaic cells (6) are retained and protected by a transparent elastomer layer (12) extruded when hot prior to vulcanization and applied against the cells with a slight pressure to cause it to go into the spaces between cells, and vulcanized by heating, for example at 110.degree. C. or at 180.degree. C., thanks to the presence of incorporated peroxides.Application in the production of electricity from solar energy.

Abstract: A method of manufacturing a dense silicon carbide ceramic includes heat treating an alpha silicon powder in a vacuum to between 1200.degree. and 1400.degree. C., adding a boron powder either before or after heat treating, then, adding a substance containing carbon, milling the mixture, compressing the milled mixture into a desired shape, sintering the formed shape at 2100.degree. C. in an argon atmosphere. The method has particular application to manufacturing parts for gas turbines.

Abstract: An electric cell with a non-aqueous electrolyte. The cell includes a positive electrode whose active material is suitable for inserting the negative active material dynamically, a negative electrode whose active material includes at least one alkali metal, and an electrolyte, wherein said positive electrode includes at least one compound whose general formula is MX.sub.4 R.sub.n T.sub.p, where M represents an element chosen from among silicon, germanium, tin and lead, X represents sulphur, selenium or tellurium, R and T represent an element chosen from among copper, silver, manganese, iron, cobalt and nickel, n being greater than or equal to 0 and less than or equal to 4, p being greater than or equal to 0 and less than or equal to 2. The invention is used in connection with button type electric cells.

Abstract: A secondary electric cell which includes: a non-aqueous electrolyte, a negative electrode whose active material includes at least one alkali metal in contact with the electrolyte, and a positive electrode whose active material is suitable for intercalating the active material of the negative electrode, wherein said positive electrode includes an active compound or solid solution whose general formula is M.sub.x X, R.sub.y X.sub.3 where:M is an element chosen from lead and tin;R is an element chosen from bismuth and antimony; andX is an element chosen from sulphur and selenium, with x having a value lying between 0 and 1 (inclusive), and y having a value lying between 0 and 2 (inclusive). Such cells may be used in watches or pacemakers.

Abstract: The gas laser includes in particular a cathode (2) which is substantially cylindrical about an axis (10) parallel with the axis of the laser cavity, said cathode being provided with protrusions (11) formed by grooves in which insulated conductor wires (12) are disposed, said wires being brought to an electric potential which is positive with respect to that of the cathode, and means for rotating the cathode on its axis. Cathode rotation serves to cool the cathode during operation and can also be used to circulate the active gas. Application to welding and to machining.

Abstract: The invention relates to an electrode for a lead accumulator. It includes an electronically conductive core coated with an active material which contains grains of lead monoxide, lead sulphate and a binding agent which is suitable for forming a three-dimensional thread-like network, characterized in that said electrode further includes a material which is insoluble in sulphuric acid and permeable to conductivity ions, the material being chosen from the group which includes polyacrylic acid and hydroxyethylmethacrylate and being used in a proportion by weight of 0.25 to 2% with respect to said lead monoxide.

Abstract: A device which measures the mutual coherence function of a laser beam. The device includes: a screen 1 in which openings 3 to 11 are disposed on the path of the beam 2 and allow pencils of light 19, 29 and 34 to pass; an interferometer constituted by an optical plate 13, a dihedron 14 and a mirror 21; a phase modulator 22 disposed on a branch of the interferometer; receivers 23 to 27 which receive the pencils of light 20 and 33 which emerge from the interferometer; and a processing circuit 36. Application to the analysis of a laser beam.

Abstract: A device for producing an electric discharge in a flat-plate transmission line.The device includes at least a first electrode (8), a second electrode (9) opposite the first electrode and passing through a hole (5) in the transmission line (1). With this arrangement it is possible to avoid deposits of metal particles building up on the edges of the hole and eventually shorting together opposite sides of the transmission line.Such flat-plate transmission lines are used in particular in nitrogen laser generators.

Abstract: The invention relates to a gas laser which comprises a flat plate transmission line, for laser excitation formed by an insulating plate (1) placed between two charged metal plates (2,3,7). The line also includes a semi-conductor layer (13) disposed on a surface of the insulating plate to reduce progressively the surface electric field on the insulating plate, from the edge (14) of the metal plate (2,3) to the edge (16) of the insulating plate. Application to remote detection of polluting gases in the atmosphere.

Abstract: Mode coupling using grating of ridges and furrows to curve the fibre along a zig-zag path are associated with an index matcher which surrounds the fibre. The average axis of the zig-zag fibre coincides that of the matcher. Light travels along lines all at the same angle to the axis of the matcher and pass through via a conical optical end surface thereof. The optical surface converts the said rays into a parallel beam for coupling with large aperture optical means such as a photo-cell or a LED.