Thomson-csf

Pierre Hartemann

Jean P Castera

Gerard Coussot

Gerard Doriath

Jean M Dupont

Gerard Volluet

Alain Jacobelli

Paul-Louis Meunier

Jean-Paul Castera

Gerard Forterre

Roger Torguet

Michel Valdois

Patrick Levesque

Jean-Paul Do-huu

Joel Martin

A tunable high-frequency device using a superconductive thin layer with a thickness smaller than the thickness of penetration of a magnetic field is positioned on a dielectric layer. Also included is a means for varying the density of the Cooper pairs of the superconductive thin layer.

Tunable high-frequency devices

A radiation detector comprising an element made of superconductive material supplied by an electrical generator as well as a system to measure the resistance of the element. For example, the generator is a constant voltage source. The measuring system utilizes a resistor placed in series with the superconductive element and a voltage measuring apparatus connected to the terminals of the resistor. Incident radiation has the effect of causing variations in the resistance of the superconductive element. Consequently, from the value of the resistance of the superconductive element, the intensity of the radiation received is detected. The disclosed device can be applied to the detection of radiation located between the visible wavelengths and the dwarf wavelengths.

Radiation detector

A measurement head for a magnetic field gradient vector measuring apparatus, comprising essentially a laser diode emitting two light beams aligned along the same axis. Two magnetic field measuring cells are placed in the paths of these light beams. Each cell comprises a wafer coated with a layer of a magnetic material forming a waveguide. The purpose of each cell is to measure the Faraday effect on the polarization of the magnetic field by using a zero method. A difference circuit then calculates the difference between the commands given to each cell so as to find the value of the magnetic field gradient.

Measurement head for a magnetic field gradient vector measuring

A process and apparatus for measuring a magnetic field based on the Faraday effect rotation of a light beam passing through a ferrimagnetic coating subject to a magnetic field to be measured is shown. The magnetization direction within the ferrimagnetic coating is coherently oriented by applying a high amplitude alternating magnetic field oriented in accordance with the axis of the light beam. This is followed by a progressive reduction of the amplitude of this magnetic field and the magnetic field to be measured is compensated. A system and a measuring cell making it possible to perform said process is also shown.

Measuring system and measuring cell for making magnetic field

A device for therapeutic heating by hyperthermia comprises an emitter which focuses ultrasonic radiation into biological tissues and produces localized heating, especially for the treatment of tumors. The radiation emitter consists of a piezoelectric plate subdivided into annular radiating zones of equal width by a set of concentric circular grooves.

Device for localized heating of biological tissues

An elastic surface wave accelerometer having a deformable structure, fixed at one end and providing at its free end a seismic mass. The deformable structure may be an open frame with a single post or a closed frame with two posts. The accelerometer can measure movement of a missile or that of a gravitational field.

Elastic surface wave accelerometers

Tunable selective devices utilizing forward magnetostatic bulk waves. A filter is able to act as an oscillator loop or as a passive transmission system in which two resonant cavities including gratings are so arranged that via a selective reflector grating they may exchange magnetostatic bulk waves energized and intercepted by transducers of the microstrip type. The invention relates in particular to the filtering of very high frequency electric signals, and to the production of tunable oscillators and to measuring magnetic fields.

Tunable selective device using magnetostatic bulk waves

In a method for fixing a ferrite to a metal piece such as a pole-piece of a magnetic polarizing circuit of a microwave device, a first step consists in depositing a nonresistive metal on the ferrite face to be fixed. A second step consists in applying a very thin layer of heat-conducting adhesive on the metallized ferrite face and bonding the ferrite to the metal piece, thus ensuring low thermal resistance, very low insertion loss and high power capability.

Method of fixing a ferrite to a metal piece

A magnetostatic wave device in which waves propagate in a layer of magnetic material grown on a non-magnetic crystalline substrate with a grating arranged in the wave path for modifying propagation velocity. The grating is formed by ion implantation without removal of magnetic material so coupling with spin modes is avoided.

Magnetostatic wave dioptric device

The volume magnetostatic wave device comprises a unidirectional-radiation transducer composed of equidistant microstrips connected to a polyphase transformer and coupled to a ferrimagnetic wafer which is subjected to a polarizing magnetic field.

Volume magnetostatic wave device

A flowmeter incorporating a pressure differential member creating a differential pressure between an upstream flow path and a downstream flow path of a pipe. The flowmeter has pressure connecting lines located on either side of the pressure differential member and constituted by conduits issuing on the surface of the device. The pressures in the upstream and downstream flow paths are transferred to a differential pressure sensor constituted by two elastic surface wave oscillators supplying signals, whose frequency is proportional to the pressures. The signals are then transmitted to a mixer, whose output supplies a beat signal, whose frequency is equal to the difference of the frequencies of the signal supplied by the oscillators. This frequency difference is directly proportional to the differential pressure.

Device for measuring the flow rate of a fluid and air flow sensor system

A unidirectional magnetometer comprising at least two magnetostatic wave oscillators with resonators or delay lines, made in two portions in a magnetic material layer respectively subject to the field to be measured and to given magnetic fields of the same direction, but of opposite sense and adjacent intensities.

Magnetostatic wave magnetometer

An arrangement for temperature compensating transducers including two elastic surface wave oscillators whose frequencies are mixed to produce an output frequency that is a function of a parameter to be measured such as force, pressure or acceleration. A delay element such as a transmission line having a delay that is a function of temperature is inserted into the loop of at least one of the oscillators to balance oscillator frequency deviations resulting from temperature changes.

Process for compensating temperature variations in surface wave devices

A sensor of the type comprising two delay lines forming part of two oscillators whose output signals are mixed and in particular a surface acoustic wave sensor comprising a wafer made from a piezoelectric material comprising a calibrating device for calibrating the output frequency constituted by an additional delay line formed by a metal strip inserted in the connections of one of the oscillators. By means of a laser beam indentations are formed in this metal strip, thus causing an increase in the delay for adjusting the frequency of the output signals of the sensor to a predetermined value.

Sensor using two tunable oscillators connected to a frequency mixer

The invention relates to elastic surface wave pressure transducers. The invention has for its object a pressure transducer in which the plate is fixed by its periphery to a support having a central cavity in which a separating wall, forming an intermediate support, defines two chambers subject to the action of the pressures to be measured. The invention is more particularly applicable to the measurement of pressures and flow rates in the field of internal combustion engines.

Growing community of inventors

Paris, France

Pierre Hartemann