Abstract: A monolithic miniature accelerometer machined in a plate of material, comprising a fixed part, two first mobile mass parts referred to as inertial masses, two hinge blades each having one end fastened to one of the two mobile mass parts, and two resonators each having one end fastened to one of the two mobile mass parts, a third mobile mass part fastened to the other end of each of the two resonators and of each of the two hinge blades, and a flexible stem situated between the first two mobile mass parts and connecting the third mobile mass part to the fixed part.

Abstract: The invention relates to conjugated compounds of general formula (I) ##STR1## wherein X.sub.1 and X.sub.2 are, independently of one another, electron-withdrawing or electron-donating systems, and to a process for the preparation of these compounds.The invention also relates to any material which includes the compounds of general formula I and to the use of said compounds or of any material which includes them in electronic, optoelectronic, nonlinear optical and electrooptical devices.

Abstract: A thermal barrier coating for a superalloy part used, in particular, in turbomachines comprises a ceramic coating and a sub-layer interposed between the superalloy substrate and the ceramic coating, the sub-layer being composed of a nickel and/or cobalt aluminide containing at least one platinum-like metal and at least one metal for promoting the formation of a layer of oxide constituted by the alpha-allotropic variety of alumina.

Abstract: A system for transmitting optical information uses several transmitters and receivers connected by optical fibers. The transmitters and receivers are arranged in individual networks in each of which all the optical fibers leaving the transmitters are coupled to one another and all the optical fibers arriving at the receivers are coupled to one another. In addition, all the optical fibers leaving the transmitters in each individual network are interconnected to the corresponding optical fibers, i.e., those leaving the transmitters, in all the other networks.

Abstract: Apparatus for processing digitized images, the apparatus being of the type comprising a matrix memory (104) of pixels (106) organized as N lines (108) by P columns (110), together with processing means (130) for determining which pixels (106) are in the excited state by reading the memory (104). The processing means (130) operate by determining and storing the address of an excited pixel (106) that occupies an extreme position in a line or a column position, by switching said pixel (106) to a non-excited state, and by reiterating these operations until none of the pixels (106) is excited.

Abstract: A propeller nozzle, particularly for a missile, comprises a revolution pipe having a forward convergent portion, a minimum section, and a rearward divergent portion with a large outlet throat section. The invention is designed to minimize lateral forces in the nozzle due to a separation of gaseous fluid exhausting from the propeller, during the start of the propeller pressure increase. For this purpose, the pipe comprises means disposed in the vicinity of a section internal to the divergent portion and substantially downstream from the minimum section for making a gaseous fluid separation stable, symmetrical and coaxial to the nozzle. These means can include a groove and/or a projection, preferably destroyable through mechanical erosion and/or melting under the effects of the gaseous fluid.

Abstract: The electron gun comprises an ionization chamber, adjacent to a high voltage chamber. In the wall common the both chambers provision is made for an extraction grid. On the opposite side, the ionization chamber comprises an outlet window for the electrons similar in shape to the extraction grid, and accompanied by a fine metallic foil. The high voltage chamber comprises a cathode brought to a high negative voltage. By giving the two grids the shape of similar parallel strips, a masking effect and a focusing effect are obtained at one and the same time which allows the efficiency of the electron gun to be increased.

Abstract: The invention relates to improvements to air propellers in so far as the profile of their blades is concerned. The law of evolution of the curvatures of the extrados 2 is the following: the curvature, maximum at the leading edge A, increases first of all rapidly to reach a value of about 4 at the point B at about 4% of the length of the chord, and then decreases regularly to reach a substantially zero value at the trailing edge F. The law of evolution of the curvatures of intrados 3 is the following: the curvature, maximum at the leading edge A, decreases first of all rapidly to reach a value of about 8 at a point D at about 3.5% of the length of the chord, then decreases less rapidly to reach a zero value at a point E situated between 10% and 60% of the length of the chord, decreases further to a slightly negative value and then remains practically constant as far as the trailing edge F.

Abstract: An optical system for analyzing and correcting wave fronts comprising a deformable mirror for correcting wave fronts and a system for analyzing and detecting phase distortion, an interferometer with lateral duplication constituting the analysis system, receiving the wave front for analysis and duplicating it and deducing from two neighboring wave fronts obtained signals to control deformation of the deformable mirror, wherein this lateral duplication interferometer is a polarization interferometer consisting of a Wollaston double-refractive biprism with an angle .theta., the two prisms being assembled head to tail and cut parallel to the crystallographic axis such that the respective axes are parallel and perpendicular to the edges of the prisms, a polarizer and an analyzer on either side of the biprism and an oscillating optical member on the path of the biprism.

Abstract: A monocrystalline alloy with a high resistance to creep having a nickel base matrix, with a density of the order of 8.5 and having a percentage, by weight, composition as follows: Co 5 to 8%--Cr 6.5 to 10%--Mo 0.5 to 2.5%--W 5 to 9%--Ta 6 to 9%--Al 4.5 to 5.8%--Ti 1 to 2%--Nb 0 to 1.5%--C, Zr, and B each less than 100 ppm--Ni remainder to 100%. Furthermore, the summation Ta+Mo+1/2 W lies between 11.5% and 13.5% by weight, the atomic sum Ti+Al+Ta+Nb lies between 15.5% and 17%, the atomic sum Ta+Nb+Mo+1/2 W lies between 4% and 5.5%, the atomic sum Ti+Al+Ta+Nb+Mo+1/2 W lies between 17.5% and 19% and the atomic sum Ti+Al lies between 12.8% and 14.5%.

Abstract: Between the electrostatic sector (SE 23) and the magnetic sector (SM 30) of a mass spectrometer, there is provided a quadrupole (QP 26) which applies parallel beams to the magnetic sector whose inclination depends on the energy dispersion of the particles. A slotted lens (LF 27) corrects the divergence of the quadrupole in the perpendicular plane. A suitable relationship between the angle of the inlet face of the magnetic sector (SM 30) and the deflection angle provided thereby ensures that the second order aperture aberrations of the magnetic sector are corrected. The chromatic aberrations may be corrected by means of a hexapole (HP 25) centered on the focus of the quadrupole (QP 26). Another hexapole (HP 22) placed upstream from the electrostatic sector (SE 23) level with a constriction in vertical section of the particle beam serves to correct second order aperture aberrations related to the electrostatic sector (SE 23).

Abstract: A process for forming a titanium base alloy comprises compacting a powder formed of particles of titanium or of a mother alloy thereof and of a dispersion of fine particles of a product curbing the growth of the grain size, in a proportion per volume which is less than that which would lead to the formation of a continuous layer of fine particles about the particles of titanium powder. Then the alloy is heat treated at a temperature higher than the point of transformation into phase .beta. and quenched. The product is typically selected among S, P, B, As, Se, Te, Y and the lanthanides.

Abstract: A deformable trihedral reflector suitable for back reflecting an incident electromagnetic beam includes a trirectangular trihedron with three reflecting faces substantially orthogonal two by two. At least one part of the reflector is made of a piezoelectric material. The piezoelectric material is activated to vary the dihedral angles between the faces of the trihedron in the vicinity of the orthogonality to cause divergence of the reflected beam.

Abstract: Electrostatic triaxial accelerometer comprising a test weight movable with respect to an accelerometer body, electrically connected to said body by a highly flexible lead, electrodes fixed to said body and forming capacitors with respect to the test weight, means for detecting the test weight position by means of measurement voltages fed to said electrodes and means for positioning said test weight by electrostatic forces developed from cueing voltages applied to said electrodes, characterized in that the test weight comprises six planar plates regularly assembled such that the inside volume defined by these plates is a cube with a side smaller in length than the plates.

Abstract: The invention relates to a method and to a structural element for protecting an aircraft against the building-up, when flying, of electrostatic charges on the external metallic surface of the aircraft normally coated with a finishing dielectric paint.The structural element of the aircraft is subjected to a treatment consisting in applying on the external metallic surface of the aircraft, prior to the depositing of the finishing paint, a resistive electrostatic protection layer having a surface resistivity of between 1 and 100 M.OMEGA. per square and being connected to the reference electric potential (i.e., ground or mass) of the frame or body of the aircraft.The the protective layer is provided, for example, by applying at least a paint layer forming, once dry, a coating exhibiting the required surface resistivity.

Abstract: The present invention relates to a process and device for the accelerated densification of a porous carbonaceous substrate, of the type consisting in decomposing a hydrocarbon substance in the presence of said substrate under high pressure and at high temperature, decomposition being effected inside a closed reactor allowing the elimination of the hydrogen emitted during the reaction as it is produced, the walls of said reactor having the necessary suppleness for the inner volume thereof to be adapted at any instant, under the effect of the pressure applied, to the volume of the liquid phase which it contains, wherein the hydrocarbon substance to be decomposed is chosen from the group comprising pitches, acenaphthylene, phenanthrene or mixtures of these products. The invention also relates to a process for preparing said substance.

Abstract: For exploring the high density high temperature atmosphere of a planet at a stabilized altitude, a buoyant assembly comprising an inflatable envelope is used. A container connectable with the envelope and containing a liquid selected to vaporize in the planet atmosphere to an extent which decreases above the stabilized altitude and increases under the stabilized altitude, is launched into the planet atmosphere with the envelope in folded condition.