Abstract: The invention relates to a process for producing a ceramic matrix composite (CMC) part by infiltration of a suspension (S) of a ceramic powder into a fibrous reinforcement (14). A suspension (S) of ceramic powder containing particles of chosen particle size, dispersed in at least one solvent, is prepared. The infiltration of the suspension is carried out in a single step in the fibrous reinforcement (14) positioned between a mold (12) and a permeable membrane (16), which makes it possible to apply a vacuum (V) and to subsequently remove the solvent from the suspension through the permeable membrane (16). The invention applies to the production of large-sized parts of complex shape, in particular in the field of aeronautics and aerospace engineering.

Abstract: Method and monopole antenna for making uniform the radiation of the antenna, when disposed inside a radome. According to the invention, on the surface of the monopole antenna is formed a protruding longitudinal ridge which is disposed at least approximately opposite an area of the radiating pattern of the assembly radome (1)-monopole antenna having a reduced gain in comparison with the radiating pattern of said monopole antenna alone.

Abstract: According to one aspect, the invention relates to an optic fiber amplifier having a high Brillouin threshold, and including: an amplification optic fiber (16) comprising a core and a sheath and suitable for amplifying a signal beam travelling in said core; means for coupling the signal beam in an input end of said amplification optic fiber; means for coupling a pump laser beam for pumping said amplification optic fiber; a structure (330, 340) including a deformable portion around which at least one portion of said amplification optic fiber is wound in the shape of turns, said turns being in contact with a surface of said deformable portion, wherein the friction of said optic fiber on said surface resulting, during the deformation of said deformable portion, in an elongation of said amplification optic fiber according to an elongation profile that varies from one turn to the other.

Abstract: According to one aspect, the invention relates to a device (20, 50) for controlling the phase of an incident optical wavefront of wavelength comprised in a spectral band of given use, comprising a substrate (21) that is at least partially transparent in said spectral band and a set of strips (22i, 23i, 24i) arranged substantially perpendicularly to the surface of the substrate, characterised in that: said set of strips comprises an alternation of juxtaposed strips respectively made of a metal (22i), of a first dielectric (23i) and of at least one second dielectric (24i) different from the first dielectric, such as to form juxtaposed metal/multi dielectric/metal (MmultiDM) structures (Si) of subwavelength widths (wi), each structure forming a cavity having one or more propagation modes—the respective thicknesses of the strips made of the first dielectric and of the second dielectric(s) are adjusted in each of said MmultiDM structures to induce a local shift (??i) in the phase of the wavefront, the local phase

Abstract: The device (10) comprises a cylindrical resonator (R) vibrating in extension-compression along its longitudinal axis (?) and having a vibration node (N) in its mid-plane (?), the vibration naturally generating radial extension/compression deformations, and a mechanical decoupling module comprising a hollow cylinder (2) surrounding the resonator and a membrane (1) positioned in the aforementioned mid-plane and rigidly connected to the cylindrical surface of the resonator and to the internal cylindrical surface of the hollow cylinder. The hollow cylinder vibrates in extension/compression in antiphase with the vibration of the resonator, enabling the effects of the radial deformations of the hollow cylinder and of the resonator to compensate each other in an area (ZF) located on the external surface of the hollow cylinder close to the mid-plane.

Abstract: Device and method for anticipating the deposition of ice on a runway, comprising an object having a non-zero relative velocity with respect to the atmosphere surrounding the runway, this surrounding atmosphere being at a certain temperature, a means for determining the thickness of ice present on said moving object, which further includes a temperature sensor for measuring the temperature of the runway, a means for regulating the temperature of said object in such a way that the temperature of said moving object is substantially equal to or slightly below the temperature of the runway, a computing means, for defining at time t0 a level of icing at time t1 of the runway as a function of the thickness of ice present on the object, and a warning means allowing the results obtained by the computing means to be communicated to a monitoring station.

Abstract: An optical probe for measuring physical and chemical characteristics of a transparent fluid medium during flow comprises two fingers parallel to one another and to the flow. Each finger consists of a solid bar of transparent material, in which a light beam propagates and is reflected on an end face of the bar, said face being situated upstream in the flow. Such an optical probe may be reduced in size, and provides results which are less sensitive to disturbances of the flow that are caused by the probe itself.

Abstract: According to one aspect, the invention relates to an optic fiber amplifier having a high Brillouin threshold, and including: an amplification optic fiber (16) comprising a core and a sheath and suitable for amplifying a signal beam travelling in said core; means for coupling the signal beam in an input end of said amplification optic fiber; means for coupling a pump laser beam for pumping said amplification optic fiber; a structure (330, 340) including a deformable portion around which at least one portion of said amplification optic fiber is wound in the shape of turns, said turns being in contact with a surface of said deformable portion, wherein the friction of said optic fiber on said surface resulting, during the deformation of said deformable portion, in an elongation of said amplification optic fiber according to an elongation profile that varies from one turn to the other.

Abstract: Generator (1) of synthetic jets (2) for a main flow of fluid, comprising a cavity (10) delimited by a fixed wall (13) and a mobile wall. The fixed wall comprises a sleeve (8) and a head (4) provided with an orifice (14) through which the generated jet of fluid (2) is drawn in from and ejected into the main flow of fluid. The mobile wall is opposite the head. The generator comprises a rigid piston (3) including the mobile wall and sliding in a fluid-tight manner in the sleeve (8), and comprises an actuator mechanically linked with the piston and able to drive the piston with an alternating movement having an amplitude and a frequency. The actuator is capable of providing a movement of variable amplitude and frequency, at least the amplitude being variable during the movement. The actuator comprises a mechanism for the mechanical amplification of displacement.

Abstract: According to one aspect, the invention relates a spectral band-pass filter, which is optimized for the transmission of an incident wave at at least a first given central wavelength ?0, and which includes: a metal grating having a thickness (t) greater than approximately ?0/50 and including at least a first set of substantially identical, parallel slots having a width (W) less than around ?0/10, and being spaced apart periodically or quasi-periodically according to a first period that is less than said first central wavelength, a layer of dielectric material having a thickness (h) and a given refractive index (ng), which is coupled to the metal grating to form a waveguide for the waves diffracted by the grating, said first period of the grating being designed such that only orders 0 and ±1 of a wave having normal incidence and a wavelength ?0 are diffracted in the layer of dielectric material, the assembly of the dielectric layer and grating being suspended, during use, in a fluid having a refractive index of

Abstract: The invention relates to a measurement by means of atom interferometry, using a Raman source that is created by modulating a monochromatic laser source. By conveniently selecting positions in which interactions between atoms and a laser radiation, produced by the Raman source, are caused, it is possible to eliminate or at least reduce a measurement bias caused by supplementary components of the laser radiation. Such a measurement having eliminated or reduced bias can be used in an inertia sensor.

Abstract: An atom interferometer with differential inertial measurement comprises an atom source system to supply several sets of atoms intended for acceleration measurements which are made simultaneously at different respective locations. The sets of atoms are transported by a dedicated system between an initial position and the locations at which the acceleration measurements are made. The interferometer can be used to obtain highly accurate acceleration or gravity gradient measurement results.

Abstract: The Coriolis-effect gyrometer has a tuning fork having two tines, which tuning fork is formed in a plate of piezoelectric crystal and provided with electrodes composed of ribbon conductors supported solely by the faces of the tines parallel to the plate. The drive excitation and drive detection electrodes are connected to an oscillator circuit, and the Coriolis detection electrodes are connected to a detection circuit. For each of the faces parallel to the plate of each of the tines the drive detection ribbon is disposed between the drive excitation ribbon and the Coriolis detection ribbon and is connected to the inverting input of an operational amplifier, the non-inverting input of which is connected to the electric ground, said operational amplifier forming part of the oscillator circuit.

Abstract: The present disclosure relates to a vibrating element which is planar parallelly to an electrical crystallographic axis of a piezoelectric material such as quartz. The element comprises a beam holding electrodes, a stationary portion rigidly connected to one end of the beam, and a solid portion rigidly connected to the other end of the beam. The structure with facets from the chemical machining of the element has an axis of symmetry parallel to the electrical axis, and the solid portion has a center of gravity on the axis of symmetry. The useful vibration modes of the vibrating element, according to which the solid portion is reciprocatingly rotated about the axis of symmetry and reciprocatingly moved parallel to the plane of the element, are uncoupled. The measurement of an angular speed by a rate gyroscope including said vibrating elements is more precise.

Abstract: A blade for a fan of a turbomachine, for example of unducted fan type, a corresponding fan, and a corresponding turbomachine. The blade includes a mechanism arranged, at a single location, to locally, as the fan rotates, disturb a distribution of flow around the blade so as to form two independent main vortices downstream.

Abstract: The present disclosure relates to an imaging system comprising an impulsion light source for an input light beam oriented toward an observed area and an optoelectronic sensor having a photosensitive surface with a visibility capable of substantially covering the observed area. An impulsion of the incident light beam is backscattered by only by a portion of the observed area into a backscattered spot on the photosensitive surface. A deflection device deflects the impulsions of the incident light beam onto the respective portions of the observed area. A device acquires the thumbnail images corresponding to the backscattered spots resulting in impulsions of the incident light beam. The system combines said thumbnail images to produce an image having a sufficiently high signal-to-noise ratio for portions of interest of the observed area, a high spatial resolution, and a greater insensitivity to motion blurs.

Abstract: The invention relates to a device for passively or actively detecting a target which scatters a useful signal and which is immersed in an observed area comprising elements that are likely to generate clutter echoes forming a non-useful signal, the useful signal having a coherent scattering lobe that is greater than that of the non-useful signal for a given wavelength and given direction, said device including means for receiving the signal scattered by the target, said receiving means including: at a given moment t, at least two separate reception portions having the same polarization, each portion including at least one receiver and one phase center; and a processing means enabling the mutual correlation between at least two received signals, or between at least two signals constructed from signals received at a moment t, each of said received signals being received by a receiver of one of said at least two separate reception portions, characterized in that the phase centers of said at least two reception po

Abstract: According to one aspect, the invention relates to a microbolometer array for thermal detection of light radiation in a given spectral band, comprising a supporting substrate and an array of microbolometers (300) of given dimensions, arranged in an array. Each of said microbolometers comprises a membrane (301) suspended above said supporting substrate, said membrane consisting of an element (305) for absorbing the incident radiation and a thermometric element (304) in thermal contact with the absorber, electrically insulated from said absorber element. The absorber element comprises at least one first metal/insulator/metal (MIM) structure comprising a multilayer of three superposed films of submicron-order thickness i.e. a first metallic film (311), a dielectric film (310), and a second metallic film (309), said MIM structure being able to have a resonant absorption of said incident radiation at at least one wavelength in said spectral band.

Abstract: The device (10) comprises a cylindrical resonator (R) vibrating in extension-compression along its longitudinal axis (?) and having a vibration node (N) in its mid-plane (?), the vibration naturally generating radial extension/compression deformations, and a mechanical decoupling module comprising a hollow cylinder (2) surrounding the resonator and a membrane (1) positioned in the aforementioned mid-plane and rigidly connected to the cylindrical surface of the resonator and to the internal cylindrical surface of the hollow cylinder. The hollow cylinder vibrates in extension/compression in antiphase with the vibration of the resonator, enabling the effects of the radial deformations of the hollow cylinder and of the resonator to compensate each other in an area (ZF) located on the external surface of the hollow cylinder close to the mid-plane.

Abstract: The imaging system for imaging field rays comprises a detection surface, a device for focusing the field rays with said detection surface, and a diaphragm. Said device comprises a Fresnel lens comprising a first dioptre, the non-plane surface of which, called the active zone, makes it possible to focus the field rays towards said detection surface, and said diaphragm allows controlled distribution of the field rays over said active zone.