Abstract: The invention concerns an installation with piezoelectric element for transmitting or receiving ultrasonic waves in a structure, the electrodes (8) of said element (7) being connected, as the case may be, to a powering circuit producing energizing electric signals designed to enable it to transmit ultrasonic signals in said structure (6), or to a circuit receiving electric signals transmitted by said element under an energizing ultrasound received by it from said structure, said piezoelectric element (7) being integrated in the structure. The powering or receiving circuits of said piezoelectric elements (7) consist each of a magnetic induction loop (9) likewise comprised in the structure (6) and capable of receiving from an external circuit (10, 11) or respectively transmitting thereto, electromagnetic signals.

Abstract: The invention concerns a transducer constituting the sensitive member of a sensor whose frequency varies as a function of the intensity of force applied to it. The force transducer comprises a beam having length and rectangular cross-section with thickness and width and flexionally vibrating. The beam has a thickness reduced over a central portion of its length, its width remaining constant.

Abstract: An emitter for emitting electromagnetic pulses includes a generator for generating an electromagnetic pulse, an optical fiber that transmits the eletromagnetic pulse, and an optical cavity. The optical cavity is placed in the path of the incident electromagnetic pulse transmitted by the optical fiber and has an input provided with a first partially reflecting mirror and an output provided with a second partially reflecting mirror. The first partially reflecting mirror is placed between first and second fiber lengths of the optical fiber and the second partially reflecting mirror is placed between the second and a third fiber length of the optical fiber. The length of the second fiber and a transmission/reflection ratio of the first and second mirrors are adjusted such that a train of electromagnetic pulses, having variable geometry characteristics, is emitted.

Abstract: A radial turbine with a novel inlet and a outlet is combined with a centrifugal compressor, also having novel inlet and outlet, so as to obtain a turbocompressor unit wherein the respective inlets and/or exhausts of which are improved. The combination of above improves the overall efficiency of the turbocompressor unit. In addition, the combination limits the axial bulk of such a unit at the cost of a limited increase both in the cross section and the weight and structural complexity of the turbocompressor unit. Such a turbomachine: a radial turbine with an optional centrifugal compressor can be produced using two-microelectronic dimensional machining techniques of the microelectronic type.

Abstract: In a process for analyzing the wavefront of a light beam, a diffraction grating with rectangular meshing is placed in a plane perpendicular to the light beam to be analyzed and optically conjugate with the analysis plane. Different emergent beams from the grating interfere to form an image whose deformations are related to the slopes of the wavefront analyzed. The grating multiplies an intensity function, implemented by a two-dimensional intensity grating, which defines a rectangular meshing of sub-pupils transmitting the light from the beam to be analyzed into a plurality of emergent beams disposed in accordance with a rectangular meshing, with a phase function implemented by a two-dimension phase grating which introduces a phase shift between two adjacent emergent beams such that the two emergent beams are in phase opposition.

Abstract: A method and device for measuring the speed of at least one object by Doppler effect, whereby the light diffused by an object illuminated by a laser sheet is transmitted to a CCD video camera by spectral filtering means which are substantially tuned to the laser illumination frequency, means being provided to generate reference monochromatic luminous fluxes having frequencies which are different from the laser illumination frequency by fixed known amounts, and the reference luminous fluxes being transmitted to the CCD video camera.

Abstract: The invention concerns a transducer constituting the sensitive member of a sensor whose frequency varies as a function of the intensity of force applied to it. The force transducer comprises a beam having length and rectangular cross-section with thickness and width and flexionally vibrating. The beam has a thickness reduced over a central portion of its length, its width remaining constant.

Abstract: The present invention relates to a method for reducing the blade-vortex interaction noise of rotary wings. According to the invention: at least one value &PSgr;o of the azimuth of the blades (1) is determined, for which value said blades shed tip vortices giving rise to a peak intensity of noise; a trailing edge flap (2) is disposed on each blade (1), the former generating an auxiliary vortex (11), parallel to the tip vortex (10) and attached to a blade section (8) lying between the blade section (7) around which the speed circulation is a maximum and the tip section (3) of said blade; and a deflection is applied to each of said flaps (2) such that, for said value &PSgr;o, the speed circulation around said blade section (8) is a specified fraction of the maximum speed circulation.

Abstract: A vibrating rate gyro structure machined in a plate of material and comprising a fixed part, a resonator, and a mechanical system connecting the resonator to the fixed part. The mechanical system comprises a first mobile mass part connected to one end of the resonator, a second mobile mass part (4) connected to the resonator and situated in the vicinity of the other end of the resonator, two flexible arms situated on both sides of the resonator and each connecting the first mobile mass part to the second mobile mass part, and two other flexible arms situated on both sides of the resonator and connecting the second mobile mass part to the fixed part.

Abstract: A vibrating rate gyro structure machined in a plate of material and comprising a fixed part, a resonator, and a mechanical system connecting the resonator to the fixed part. The mechanical system comprises a first mobile mass part connected to one end of the resonator, a second mobile mass part (4) connected to the resonator and situated in the vicinity of the other end of the resonator, two flexible arms situated on both sides of the resonator and each connecting the first mobile mass part to the second mobile mass part, and two other flexible arms situated on both sides of the resonator and connecting the second mobile mass part to the fixed part.

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: Alloy of the Ti2AlX type composed at least essentially of the elements Ti, Al, Nb, Ta and Mo and in which the relative amounts as atoms of said elements and of silicon are substantially within the following intervals: Al: 20 to 25% Nb: 10 to 15% Ta: 1.4 to 5%   Mo: 2 to 4% Ti: remainder to 100%. This alloy exhibits properties superior to those of the known titanium alloys.

Abstract: A "master-slave" remote manipulation apparatus having six degrees of freedom. The apparatus includes a flexible parallelogram with two parallel arms hinged to a cross member with one degree of rotational freedom and to a frame with two degrees of rotational freedom; two parallel-hinged "master" and "slave" devices at the end of each respective arm; and five two-way linear motion transmitting devices between the "master" and "slave" devices.