Abstract: A method and apparatus for remote optical detection of a gas present in an observed volume using a thermal imager or camera including one or more sensitive elements which are sensitive to radiant fluxes in a determined band of wavelengths, two filters interposable on the optical axis of the camera, the filters having similar transmission bands, one of which includes an absorption line characteristic of the looked-for gas, while the other of which is complementary to said absorption line, and signal processing means for taking the difference between the radiated fluxes received from two points at different temperatures in the volume as observed first through one of the filters and then through the other filter, for taking the ratio of said differences, and for deducing therefrom whether the gas is present in the observed volume.

Abstract: A device compares two variable analogue signals, e.g. varying in time, such as audio or video signals. The signals, which are either different or identical but shifted in time, are within a predetermined frequency range. The device includes two parallel channels for processing analogue signals. One of the channels introduces a time shift of one signal with respect to the other, the shift being equal to a 1/4 period at the center frequency of the band. Both channels include in series circuits for transforming the analogue signals into binary logic signals, a logic circuit, a summing circuit for establishing a first and second correlation signal. An adder adds the absolute values of the first and second correlation signals to form a third correlation signal that is substantially independent of any time shift between the analogue signals.

Abstract: A process of separating plasmids and cosmids from bacterial cells in which they are contained, comprising adding cultured bacterial cells separated from a culture medium to an inclusion gel-forming substance; lysing the bacterial cells; solubilizing the thus lysed bacterial cells; solidifying the inclusion gel-forming substance to form a gel either before or after the step of solubilizing; and applying an electric field to the thus formed gel sufficient to cause electrophoretic migration of the plasmids and cosmids and isolation of the plasmids and cosmids. Also disclosed is a device for carrying out the process.

Abstract: A frame for use in making a membrane lined with a gel layer includes two spaced apart bars to which opposite edges of a membrane can be connected and which are connected by two pairs of elastic strips. Cam elements are positioned between the strips of each pair of elastic strips to move the strips apart or allow them to come together, thereby causing the bars to move together for attachment of the membrane, or apart to stretch and tension the membrane after a gel has been cast thereon.

Abstract: A cell culture device is disclosed where cells are confined in a liquid medium within a cell culture space. The cell culture space is delimited by at least three selectively permeable walls. One wall is formed by a sheet of tubes and is permeable to fresh nutrient medium, the second wall is formed of a layer of capillaries and is permeable to gaseous fluids, and the third wall acts as a micron sieve that allows the passage of spent nutrient medium, but retains the cells within the cell culture space. The cell culture device makes it possible to produce culture products, continuously and in bulk over a long period of time.

Abstract: Apparatus for determining the three-dimensional shape of an object by projecting patterns onto the surface of the object, the patterns having fringes with a light intensity that varies sinusoidally in space, said apparatus comprising means (30, 34, 36) for changing the pattern centered on the projection optical axis (28), and cam means (54) for displacing the patterns (12a, 12b) transversely through distances equivalent to phase shifts of 2.pi./n.

Abstract: A device for the bi-directional transmission of data between a master system and a slave system uses a single transmission antenna and a single reception antenna each tuned to the same frequency; the master system comprises first data transmission circuits for transmitting first data to the slave system by modulating an electromagnetic signal at the frequency; detection circuits for detecting, during the transmission of the electromagnetic signal, variations in electrical characteristics of the master system induced by a modulation of the impedance of the slave system as a function of second data to be transmitted from the slave system to the master system; and restoring circuits for restoring the second data on the basis of the detected variations; and the slave system comprises reception circuits connected to the reception antenna for restoring the first data; a rectifier circuit connected across the reception antenna for rectifying an electrical signal induced in the reception antenna by the electromagneti

Abstract: This detector comprises a variable radio frequency oscillator (1) producing a first electrical signal, a transmission circuit (3) with a capacitive antenna to which said first signal is applied, a reception circuit (6) forming, with the transmission circuit (3), a selective coupler for picking up a second electrical signal at the frequency of the oscillator, and a circuit (9) for comparing the phases of the first and second electrical signals and producing an output signal in response to a variation of the phase shift between said signals due to the presence in the surroundings of the antenna of a foreign body to be detected.The detector further comprises a feedback circuit (13) driven by the output signal of the comparison circuit (9) and controlling the oscillator (1) in order to make the frequency of the first signal vary in the sense which tends to cancel out said variation of the phase shift.

Abstract: The sensor for detecting and measuring the angle of rotation of the polarization plane of light delivered by a sensitive system (19) subjected to an external phenomenon such as a magnetic field, for example, with the sensor being connected via an optical fiber (18) to a source of incoherent light (10) and essentially comprising the sensitive system (19), a quarterwave plate (22), a birefringent crystal (24), and an analyzer (26). The light flux provided by the sensor is spectrally modulated as a function of the angle of rotation of the plane of polarization of the light delivered by the above-mentioned system (19).

Abstract: Method and apparatus for surveillance of a determined space in which a camera lens enables an image of said space to be formed on a set of photodetectors associated with information processing means, the set of photodetectors being a linear strip of photodetectors, for example, mounted so as to be fixed relative to the lens which is itself mounted to rotate about a transverse axis and which is displaceable by drive means to occupy predetermined angular positions about said axis.

Abstract: A method and apparatus for measuring a physical magnitude by means of an incoherent light source (10), an interferometric sensor (14) modulating the spectrum of the light beam emitted by the source at a characteristic frequency which is a function of the magnitude to be measured, a demodulator interferometer (18), and spectrum analysis means (22) having optical resolution making them insensitive to the modulation frequencies generated by the sensor (14) and the demodulator interferometer (18), and sensitive to the difference therebetween. The invention is particularly applicable for measuring physical magnitudes such as temperature, motion, electric field, etc.

Abstract: The invention relates to an optical sensor using spectrum modulation encoding and operating by reflection, the sensor is connected by an optical fiber (10) to a light source and to a demodulator, and it comprises a collimator lens (16), a first polarizer (18), a sensitive component (20) subjected to the physical magnitude to be measured, a second polarizer (32), and catadioptric reflection means (28) such as a corner of a cube. The sensor of the invention enables all of the light flux to be reinserted into the optical fiber (10) after passing through the sensor without any disturbance from interference phenomena.

Abstract: The support (17) forming the element has a diameter of a magnitude order higher than its height which is itself of a magnitude order higher than its thickness. It is rigidified by means of two membranes each formed of a composite collar including, between the support (17) and a concentric rigid crown (23, 24), an elastomer ring (22) adhered thereto and presenting an axial height of the same order of magnitude as its radial thickness. These rings provide, on the one hand, for the elastic return of the support in axial displacement and, on the other hand, for the preservation of the circularity and therefore for the inherent flatness of said support.

Abstract: An optoelectronic apparatus for the remote measuring of a physical magnitude which comprises two light sources emitting luminous fluxes centered on two different wavelengths and means for controlling the alternate operation of these light sources. A sensor is provided for receiving the luminous flux emitted by the respective light sources and causing a periodic spectral modulation of the luminous flux a frequency depending on the value of the physical magnitude to be measured. An analysis means is provided for analyzing the luminous flux transmitted by the sensor, the analysis means being of the static type and including a birefringent element which is tuned to the sensor and produces an optical path difference close to that produced by the sensor.

Abstract: A multiple electrophoresis method and device are disclosed for the controlled migration of macromolecules in gel plates stacked in a direction perpendicular to their plane, at least one series of electrodes (20) disposed at the intersections of two series of peripendicular planes, some perpendicular to the plates (12) and to the desired direction of migration of the macromolecules, the others perpendicular to the first and parallel to the plates (12), the electrodes being connected together selectively and controlled so as to provide both separation of the macromolecules in the plate (12) then transfer thereof to the membranes (22) associated with the plates (12).

Abstract: The silencer includes a tubular envelope supported by an end piece for fixture to a gas supply source in which the pressure is to be reduced. A perforated plate and a disk close off the ends of the envelope which is drilled with escape apertures in the region of the disk. According to the invention, the gas flows at sonic speed through the plate to enter the envelope which is completely filled with a packing consisting of a tightly wound roll of wire mesh. The packing absorbs the shock waves developed by the supersonic flow of the gas in the packing. The latter maintains a subsonic flow with a low noise level upstream of the silencer. Application to the treatment of a surface by blasting of a gas flow is also described.

Abstract: A method and apparatus for high speed temperature regulation of elements (12) in thermal contact with a fluid contained in liquid-vapor equilibrium inside an enclosure (10) which is closed in sealed manner and which is provided with thermal insulation, temperature regulation being provided by means of an external heat source (S) imposing a reference temperature (Tc) to the fluid contained inside the enclosure (10) and causing a corresponding variation in the temperature (Te) of the elements (12) by changing the phase of the fluid. The invention is particularly applicable to performing molecular biology reactions at controlled temperature.

Abstract: The present invention provides a method and apparatus for reading bar codes having variable orientations on a substantially motionless medium. A portion of the surface of the medium having a bar code in a variable orientation is scanned using a light source and a photodetector receives the beam reflected from the surface and generates signals corresponding to the scanning lines. The signal corresponds to the scanning lines and has amplitude peaks corresponding to the intersection of the bars by the light beam. The amplitude peaks and position of the peaks on the scanning lines are recorded. The sum of the amplitude peaks is formed in the positions of the bars and deduced from the sums of the peaks amplitudes.

Abstract: The method disclosed is for treating an article, i.e., polishing an article, of the type with a rotating vessel where the article to be treated is fastened in relation to the vessel. To enable the article to be treated to be placed in position without the need to remove the particles from the vessel, the article is moved between a loading and unloading position, where the article is outside the mass of particles, and a working position, where it is subjected to the action of the particles to polish and strip pieces of furniture.

Abstract: Method and apparatus for polishing the surface of an optical component by means of a polisher (12) carried by a support (24) which is pivotally mounted at the end of a robot arm (10) and which includes means for uniformly distributing the action of the polisher over the surface of the optical component (14) together with means for adjusting said action. The invention makes it possible to accelerate and automate the polishing of optical components.