Abstract: High frequency inductive generator for the inductive coil of a plasma generator constituted by a head for inflow of gas into an inductive coil. The high frequency generator has a quarter wave anode resonant line oscillator circuit and a coupling circuit connected to the inductive coil. The quarter wave anode circuit is controlled from a single oscillator tube. One of the lines is connected to the anode of the tube, while the other is coupled exteriorly by capacitive coupling.The invention is used for analysis by emission spectrometry.

Abstract: Portable apparatus for welding by means of an oxy-gas flame, such as an oxy-acetylene or an oxy-petroleum gas flame or the like, comprises a device for supplying the gaseous fuel in gaseous form under pressure, a combustion oxygen generator and means for pressuring said combustion oxygen generator so as to make the oxygen available at a pressure compatible with the fuel delivery pressure, these means being realized by a connection between the oxygen generator and the fuel supply device.

Abstract: In a dye laser comprising a cavity, one end of which is closed by an angular dispersion system, and which is provided with a separator for extracting the laser beam from the cavity, the separator is arranged so that the dispersive system and the system for application of the laser beam are on the same side relative to the separating face of the separator. An aperture isolates the reference wavelength from the extracted beam.Such a laser can have very good monochromaticity and is useful wherever there is a need for high spectral purity, in particular in Raman spectrometry.

Abstract: Apparatus for producing an aerosol jet comprising an atomizing means and a flow of carrier gas for entraining the particles formed.Downstream of the atomizing means, the conduit for carrying the aerosol constitutes the central passage (20) of a double nozzle (21) whose annular passage (22) receives another dry gaseous flow. This thus forms a central flow of aerosol, which is sheathed externally by a flow of dry gas.The invention is used for the analysis of solutions by spectroscopy.

Abstract: A process for coding a set of access cards adapted to control an apparatus for opening, locking or releasing a processing device and for the ultimate determination of the validity of a card when it is presented in the apparatus, the coding being effected by the formation on the cards of at least one diffraction grating whose recognition is effected by projection of a luminous beam on the grating and analysis of the diffracted beams. The grating is formed by means of a machine having a kinematic drive which is intentionally irregularized to produce at least one deviation in the spacing of the lines of the grating which varies periodically with a determined period and maximum amplitude. The modified grating will produce a supplementary satellite diffraction beam when illuminated by the luminous beam and whose angular position and intensity is measured to establish the validity of the grating.

Abstract: A spectrograph for an extended spectral field having an inlet slot for defining a source of light to be analyzed and a dispersive system constituted by a concave holographic grating which has recording points with coordinates in relation with the coordinates of the light source to be analyzed to produce for each of respective bands of wavelengths, which in total cover the entire range of wavelengths of the spectral field to be analyzed, tangential focal lines for different wavelengths which are disposed in the same plane. The concave holographic grating is rotatable around an axis passing through the center of the grating and perpendicular to a plane passing through the center of the inlet slot so that the respective partial plane diffraction spectra are successively formed in the same plane when rotating the grating around its axis.

Abstract: A spectrograph for use in analyzing an extended spectral field comprising a dispersive system consisting solely of one or more concave holographic gratings, each grating being specified so that the diffraction spectrum is formed in a plane. Where a plurality of gratings are provided they are formed on a common concave support and are specified so that the planes of the diffraction spectra formed thereby are offset and in total cover the wavelengths of the total spectral field.

Abstract: A furnace for melting metal by the Joule effect to enable extraction of gases contained in the metal comprising a hollow tubular body which constitutes a heater resistor clamped between two electrodes, and a separate crucible for the metal which is supported within the tubular body and out of direct contact with the electrodes.

Abstract: A monochromator having a concave holographic grating which is turnable in rotation and provided with an inlet slot parallel to the lines of the grating for incident light and an outlet slot also parallel to the lines of the grating, the inlet and outlet slots being disposed on opposite sides of a diametrial median plane P of the grating extending perpendicular to the lines of the grating and passing through the center of the grating. The bisector of the angle A, formed by two lines connecting the center of each slot to the center of the grating is contained in the plane P, the slots being additionally disposed such that the projection .alpha. of the angle A on the plane P is .ltoreq. 3.degree. and the projection .beta. of the angle A on the plane P' containing the bisector and perpendicular to the plane P is .ltoreq. 15.degree..

Abstract: A monochromator having a fixed inlet slot, a holographic grating carried on a concave turnable support, and a fixed outlet slot, the support surface of the holographic grating being a concave portion of a toroidal surface, taken at the outer periphery of the toroid, and symmetrically disposed with respect to the equatorial plane of the toroid, the equatorial plane also containing the point sources for recording the holographic grating.