Abstract: Properties of a medium, such as its particle size distribution, are characterized using a measurement cell containing a medium between walls of the cell, with ultrasound transducers on opposite walls. Ultrasound is transmitted from the ultrasound transducers on both sides and transmission and reflection responses are detected. An ultrasound frequency dependent ratio of a Fourier transform value of a product of signals obtained from transmission responses in opposite directions and a Fourier transform value of a product of signals obtained from reflections at the transducers is computed. Preferably, the first received reflected and transmitted pulses in response to pulse excitation are used to compute the ratio. Ultrasound frequency dependent ultrasound speed and/or attenuation data of ultrasound in the medium are computed as a function of the ultrasound frequency from the ratio. This eliminates the effect of the walls.

Abstract: Properties of a medium, such as its particle size distribution, are characterized using a measurement cell containing a medium between walls of the cell, with ultrasound transducers on opposite walls. Ultrasound is transmitted from the ultrasound transducers on both sides and transmission and reflection responses are detected. An ultrasound frequency dependent ratio of a Fourier transform value of a product of signals obtained from transmission responses in opposite directions and a Fourier transform value of a product of signals obtained from reflections at the transducers is computed. Preferably, the first received reflected and transmitted pulses in response to pulse excitation are used to compute the ratio. Ultrasound frequency dependent ultrasound speed and/or attenuation data of ultrasound in the medium are computed as a function of the ultrasound frequency from the ratio. This eliminates the effect of the walls.

Abstract: This method of determination of a distribution of energy to a plurality of electrical loads (121, 122, . . . , 12n) during a modulation period (T), the energy coming from at least one generator (14), the supply of a predetermined quantity of energy to any one of the electrical loads during this modulation period being effected by the generator emitting during a predetermined fraction of the modulation period an electrical signal the power whereof corresponds to that demanded by that electrical load, includes a temporal distribution of the electrical signals emitted by the generator in the modulation period in accordance with a distribution criterion determined as a function of the electrical signals and applied successively to each electrical signal in the same modulation period. The temporal distribution criterion for the electrical signals is determined as a function of the temporal length and the power of the electrical signals.

Abstract: The invention relates to the use of block copolymers, obtained by controlled radical polymerization in the presence of alkoxyamine derivatives of substituted nitroxides, for the production of perfectly transparent acrylic films with the mechanical properties required for the applications envisaged, whereby the transparency thereof remains under mechanical stress and a wide temperature range. The total thickness is between 40 and 300 microns, preferably 70 to 90 microns. The film has a haze of less than 2 and elongation at breakage of more than 90%.

Abstract: This method of determination of a distribution of energy to a plurality of electrical loads (121, 122, . . . , 12n) during a modulation period (T), the energy coming from at least one generator (14), the supply of a predetermined quantity of energy to any one of the electrical loads during this modulation period being effected by the generator emitting during a predetermined fraction of the modulation period an electrical signal the power whereof corresponds to that demanded by that electrical load, includes a temporal distribution of the electrical signals emitted by the generator in the modulation period in accordance with a distribution criterion determined as a function of the electrical signals and applied successively to each electrical signal in the same modulation period. The temporal distribution criterion for the electrical signals is more precisely determined as a function of the temporal length and the power of the electrical signals.

Abstract: Thin, single semi conducting layer of GaInN, possibly containing a small percentage of arsenic, phosphorus or antimony, the said layer emitting at least two visible lights with determined colors which can be combined, particularly to obtain white light. Method for preparing this layer. Light emitting diode (LED), particularly a LED emitting white light comprising such a thin layer in its active zone, and lighting device comprising such a diode.

Abstract: Thin, single semi conducting layer of GaInN, possibly containing a small percentage of arsenic, phosphorus or antimony, the said layer emitting at least two visible lights with determined colours which can be combined, particularly to obtain white light.

Abstract: A device includes a silicon substrate provided with a coating including at least one stacking constituted by a plane of GaN or GaInN quantum dots emitting visible light at room temperature in a respective layer of AIN or GaN. The method of making the device is also disclosed. The device can be incorporated in electroluminescent devices and exchange devices, emitting white light in particular.

Abstract: In a process for the production of a metal by reducing a salt of said metal, an exchange is carried out between a reducing metal and a reducible metal within a fused salt bath under conditions in which the reducible metal in the reduced metal state is immiscible in the bath in the presence of the reducing metal which has previously been dissolved in the bath.

Abstract: Process for the preparation of polyanilines, polyanilines obtained according to this process and their uses in the production of electrochemical generators.This process consists of oxidizing a compound chosen from among aniline, para-aminodiphenylamine and their derivatives in a super acid in the liquid phase, having fluoride ions, e.g. in the eutectic NH.sub.3, HF, either chemically using an oxidizing agent, or electrochemically.The polyanilines obtained can be used as a positive electrode material (5) in an electrochemical generator having two current collectors (3) and (7) and a negative electrode material (9), e.g. constituted by lithium or a lithium-aluminum alloy.

Abstract: Process for preparation of glyoxylic acid through electrochemical anodic oxidation of glyoxal in aqueous solution at a temperature comprised between 0.degree. C. and 70.degree. C. in an electrolyzer comprising at least one cathodic compartment containing a cathode and a catholyte, at least one anodic compartment containing an anode and an anolyte, consisting of an aqueous solution of glyoxal and an electrolyte, and at least one separator between both of these compartments. In such process the anode is doped by metallic adatoms selected from the group comprising silver, bismuth, copper, tin and thallium.

Abstract: Display package for fragile articles such as automotive headlights consists for example of prism of resilient material having a polygonal bottom and vertical sides. A seat for a fragile article extends inward from each side and narrows as it approaches its inner end. The walls of the seat are provided with grooves and projections which mate with portions of the article to be received therein.

Abstract: In order to form galleries or other subterranean cavities in the bed of a sheet of water, for example for the construction of a subterranean reservoir for storing petroleum, or for exploiting submarine deposits, a floating structure, comprising at least one and preferably two hollow shafts, is ballasted so that it rests upon the seabed or underwater surface, a bore is excavated in extension of each hollow shaft, down to the desired depth, a casing tube is inserted there, extending to above the sheet of water, and one of said casings is used as an access means for the excavation of the galleries or cavities, whilst the other if used to remove the spoil.

Abstract: Liquid crystals subjected to an electric field are stabilized by the addition of an electrochemically active and chemically stable material capable of undergoing reversible oxidation-reduction at the electrodes applying the field to the material. The invention is particularly for use in converting electric signals to optical signals.