Abstract: The invention relates to an optical spectrum analyzer of an incident light beam (101) and a process for analyzing the corresponding spectrum. The spectrum analyzer comprises addressing means (1), a diffraction grating (2), a reflecting dihedron (3), a device (4) for adjusting the rotation of the reflecting dihedron and reception means (5). A polarization separator (11) divides the incident beam (101) into a first and second parallel secondary beam (102, 104), of linearly polarized light along the directions parallel to and perpendicular to the grooves in the grating respectively, and a .lambda./2 plate (12) placed on the path of the first secondary beam (102) applies a perpendicular polarization direction to this beam. The grating diffracts the secondary beams (103, 104) a first time, the reflecting dihedron exchanges their directions, the grating diffracts them a second time, the .lambda./2 plate applies a 90.degree.

Abstract: Data validation uses redundant storage of the data on two-layer magnetic tapes. A method and system provide data recording and reading on such magnetic tapes with a high degree of protection from errors and/or fraudulent behavior. The two-layer tape includes a first layer with a high coercive field positioned on a support and a second magnetic layer with a lower coercive field covering the first layer. Synchronous recording is done on the two layers so that all data is recorded on the second layer and some of the date is recorded on the first layer. Data on the second layer is validated upon reading by reading the data in the first layer after erasure of the second layer.

Abstract: This invention relates to a singlemode laser source tunable in wavelength with a self-aligned external cavity, comprising: a resonant cavity having an output face that is partially reflecting (331) and a retroreflecting dispersive device (31, 39), defining a main collimating axis (351) and a secondary collimating axis (381), an amplifier wave guide (33) placed in position inside the resonant cavity. The retroreflecting dispersive device comprises a plane diffraction grating (31) having dispersion planes and an orthogonal reflecting dihedral (39) whose line of intersection (391) is parallel to the dispersion plane of the diffraction grating containing the collimating axes (351, 352).

Abstract: A process and an optical gyroscope are provided for measuring rotation speeds (S) about N axes. The light source and the photodetector are common. Controlled modulation phase differences .delta..PHI..sub.c,i COMPRISE biasing components .delta..PHI..sub.m,i (42, 45, 46) with a common modulation period T.sub.m and common amplitude. Since each half-period T.sub.m /2 is divided into N time intervals .delta.t.sub.i, a change in the sign of the biasing component .delta..PHI..sub.m,i associated with each interferometer I.sub.i is produced at the beginning of one and only one .delta.t.sub.i time interval. Sagnac phase shifts .delta..PHI..sub.s,i are obtained by sampling a signal on the N time intervals.

Abstract: An appliance for measuring polarization mode dispersion (PMD) of a waveguide (2) comprises a source (1, 6) of wide-band polarized light, an interferometer (5) capable of receiving a light beam (21) sent by the source (1, 6), a detector (3) capable of detecting the light beam (25) from the interferometer (5), and an electronic processing unit (4) connected to the detector (3), capable of extracting a value .tau. representative of the polarization mode dispersion of the waveguide (2). The interferometer (5) divides a measuring light beam (22) sent by the source (1) into two interference light beams (23, 24). The measuring appliance comprises at least one birefringent element (17) positioned on the interferometer (5), capable of producing an algebraic difference of relative phase shifts in each of the two interference light beams (23, 24) equal to .pi..

Abstract: A polyol composition useful for the preparation of high resilience polyurethane foams comprising (1) from 80 to 99.8 weight percent of a high functionality polyol or a polyol blend having an average nominal functionality between 3.2 and 6, and from 0.2 to 20 weight percent, a subsidiary polyalkylene oxide having a poly(oxyethylene) content greater than 30 percent, or (2) from 50 to 98 weight percent of a high functionality polyol or a polyol blend having an average nominal functionality between 3.2 and 6, from 0 to 0.9 weight percent of a subsidiary polyalkylene oxide having poly(oxyetheylene) content greater than 30 percent, and from 2 to 50 weight percent of a polymer. The average nominal functionality of the polyol composition is between 3.2 and 6. This polyol composition provides greater latitude for varying formulation components in the preparation of high resilience polyurethane foam as with broad density and load ranges.

Abstract: The present invention relates to polyol compositions, their use in the preparation in resilience polyurethane foams and to foamed articles prepared from formulations containing such polyol formulations.

Abstract: This invention relates to a singlemode laser source tunable in wavelength with a self-aligned external cavity, comprising: a resonant cavity having an output face that is partially reflecting (331) and a retroreflecting dispersive device (31, 39), defining a main collimating axis (351) and a secondary collimating axis (381), an amplifier wave guide (33) placed in position inside the resonant cavity. The retroreflecting dispersive device comprises a plane diffraction grating (31) having dispersion planes and an orthogonal reflecting dihedral (39) whose line of intersection (391)is parallel to the dispersion plane of the diffraction grating containing the collimating axes (351, 352).

Abstract: Double pick separator device comprising means for retaining a flat object which might otherwise be entrained by friction by another flat object being moved in a predetermined transfer direction by transfer means.The retaining means are mounted on a structure mobile in a direction substantially perpendicular to the transfer direction. The separator device further comprises means for exerting a holding force on the retaining means, said holding force being oriented in a holding direction substantially perpendicular to the transfer direction.Application to automatic mail sorting, especially to sorting mail items of varying thickness.

Abstract: A flat object transfer device for transferring flat objects, particularly flat objects of varying thickness, to a sorting device from the output of an unstacking device. The flat object transfer device includes a gripping device for gripping a flat object initially located in a transfer plane. The gripping device includes a set of pinch rollers and pulleywheels on opposite sides of each pinch roller. A set of drive belts are trained around each pinch roller and the pulleywheels on opposite sides of the pinch roller. At least one of the pinch rollers in the set of pinch rollers can move in a direction substantially perpendicular to the transfer plane. A double pick separator device is provided for retaining flat objects except for a flat object to be gripped by the gripping device. The double pick separator device is disposed between two levels of the drive belts trained around the pinch rollers and pulleywheels.

Abstract: An automatic mail sorting flat object holding device has a driven perforated belt and suction grasping heads inside the belt. The holding device has a holding side consisting of the perforated belt moving in a predetermined transfer direction and to the front of which a stack of flat objects is offered up. A double pick separator has a suction head disposed substantially facing an exit edge of the holding side. The suction holding device has at least two substantially adjacent suction heads aligned in the transfer direction, one suction head of which is at least partly overlapping the double pick separator suction head.

Abstract: A munition including a submunition has a target detector and a core-generating charge with a firing axis .DELTA. for firing a projectile. The munition is designed to move relative to the ground and seek a target. The munition rotates about an axis A with a velocity translation v.sub.0. The target detector includes several detection axes .delta..sub.1 through .delta..sub.n and a device for selecting a detection axis .delta..sub.i from the detection axes .delta..sub.1 -.delta..sub.n for which the distance E between the point M.sub.i at which the axis .delta..sub.i intersects the ground and the point M' at which the projectile strikes the ground is minimal.

Abstract: A reading apparatus simultaneously detects all the magnetic states previously recorded on a length of a magnetic strip on a substrate. The apparatus has detectors for simultaneously detecting all the magnetic states coded on the magnetic strip and for generating electrical signals indicative of the magnetic states. An electronic circuit processes the electrical signals in order to determine the meaning of the magnetic states. A display shows the meaning of the magnetic states. The apparatus is used to read flexible magnetic tags attached to garments.

Abstract: The invention concerns an optical fiber measuring device, for example a gyrometer. The working of this device is independent of possible variations in the spectrum of the source. It includes a narrow, stable spectral filter which separates the incident flux. The modulation chain is slaved by a first detector (3). A second detector (23) receives the filtered flux. Its response is processed by a device (219) which supplies a signal that is a function of the spectrum of the light source (1).

Abstract: The invention relates to a fiber optic measuring device in which the variation in a measured parameter engenders a phase difference between two waves. It comprises a SAGNAC ring interferometer (2) in which two counter-propagating waves propagate; a polarization splitter (6) spatially splits the two polarizations which will propagate in the interferometer (2), interferometer (2) comprises a polarization conserving birefringent fiber (7) having two ends having neutral birefringence axes, each of the ends of the polarization conserving fiber (7) being connected to one of the gates (6b) and (6c) of the polarization splitter (6). It comprises a birefringent component, placed ahead of the polarization splitter (6) and introducing a path difference greater than the coherence length of the source (1) between the two polarized waves.

Abstract: A fiber optic measuring device can be used, for example, as a rate gyro. Variation in a measured parameters engenders a phase difference between two waves. The measuring device includes a light source 1, a SAGNAC ring interferometer 2, a detector 3, a phase modulator 4, and a electronic unit 7. The electronic unit 7 includes a processing system 9 which furnishes a signal that is a function of the measured parameter and an electronic sub-unit 12 for controlling the phase modulator 4. The control signal for the modulator is a superposition of a first, periodic gating, bias signal .PHI..sub.b (t) with period 2.tau. and amplitude .PHI..sub.bm, and of a second, staircase, negative-feedback signal .PHI..sub.m (t) synchronized with .PHI..sub.b (t), each step of which has a duration equal to .tau. or to one of its sub-multiples, and an amplitude .PHI..sub.s, which is a function of the value of the measured parameter and which falls back to zero when its amplitude exceeds a predetermined value .PHI..sub.mm . .PHI..

Abstract: An integrated circuit for the processing of digitized signals which are representative of a source image which is defined by image elements which are encoded on M bits and which are arranged in I rows and J columns. The image is processed by means of M sliding windows (W.sub.1 to W.sub.M) which consist of N rows and P columns and which step-wise slide past each image element along I rows, but which have been shifted through one row with respect to one another. Processing is performed by bit serial operators which successively act on the bits of each of the N+N-1 image elements. The signals may be serially applied via Q contact pads, where Q=N+M-1, or in parallel via Q contact pads where Q is the first multiple of M which is equal to or larger than N+M-1, the integrated circuit then also comprising a parallel to serial converter circuit.

Abstract: The invention relates to a fibre optic measuring device of the type in which the change in a measured parameter generates a phase difference between two waves in a SAGNAC ring interferometer (2). Electronic means (7) comprise a processing system (9) delivering a signal depending on the measured parameter and electronic means (12) controlling the phase modulator (4). The electronic means (12) produce a control signal for the modulator determined in such a way that the phase difference .delta..PHI..sub.m which it produces between the counter-propagating waves periodically takes the following four successive values: ##EQU1## where .PHI..sub.o is a constant phase shift and it depends on a, and a is a positive constant satisfying the condition: cos .PHI..sub.o =cos a.PHI..sub.o.

Abstract: The present invention relates to a preparation method of a paste by mixing at least one constituent substance in a solid form, notably a powder, with at least one constituent substance in a liquid form, mechanically kneading the mixture under vacuum and subjecting said mixture to vibrations under vacuum.According to the invention, the mixture is subjected to a vibration field during at least the final phase of the mechanical kneading in a device comprising a base (2), a bowl of revolution (28) carried by said base, a cover (21) closing said bowl in a tight manner, an evacuation duct (10) opening into the bowl and kneading blades (27), the bowl being suspended underneath the cover and removably connected to said cover with means (11a, 11b) for imparting vibrations to the cover and bowl assembly via the cover.The present invention applies to the preparation of alginate, plaster or similar substances based pastes.

Abstract: The invention relates to improvements to methods and devices for determining the contact angle of a drop of liquid placed on a substrate. The device comprises: a support 12 for a substrate 11 which receives a drop of liquid 9; a light source 1; optical means, formed for example by a plate with parallel faces 21 rotatable about its axis 22 and whose inclination with respect to the axis may be modified, with a reflecting prism 5a, for forming a primary beam 6a, advantageously annular, striking the interface 8 between drop and substrate; a receiving surface 13a, 13b formed by a reflection diffusing surface; a reflecting surface 17; and a camera C.