Abstract: An optical fiber cable comprises at least one central strength member, at least one optical fiber, a metallic conductor surrounding the fiber and, surrounding the conductor, a layer of an insulative composition comprising mainly a mixture of polymers comprising at least one high-density first polymer and one low-density second polymer which has a lower viscosity than the first polymer. It is preferable that the first polymer be high-density polyethylene and the second polymer be low-density polyethylene.

Abstract: An electric transformer comprising a primary coil and a secondary coil each constituted by at least a first coil formed by winding one or more metal-matrix superconductive conductors. The first coil of the primary coil or of the secondary coil is connected in series with at least one second coil formed by a solid superconductive tube machined to form a solenoid, the second coil being disposed coaxially with the first coil. This design contributes to protecting the transformer by means of its current-limiting effect.

Abstract: Lead-in module for the supply of a low critical temperature superconducting electric loadThe module (3) is located inside a cryostat (1), it is fixed to its sealing cover (2) and it comprises a pair of metal conductors (6, 7) which pass through the cover (2) and whose lower ends are connected to the upper end of a high critical temperature superconducting module (8) comprising two conductors (9, 10) electrically connected to said pair of metal conductors (6, 7) and separated by an insulating core (11) making up a mechanical reinforcement, with an insulating structure (14) whose upper end (15) is fixed to the bottom of said cover (2) of the cryostat (1), surrounding the pair of metal conductors (6, 7) in a sealed manner until its junction (16) with the superconducting module (8), the structure (14) extending in an unsealed manner until at least the lower end of the superconducting module (8), the structure (14) comprising at its lower end fastening means (20) to support the electric load (4).

Abstract: An apparatus for transferring liquid helium between axially spaced first and second endpieces, being fixed thereto at opposite ends and having an intermediate insulative portion. An outer conduit of larger diameter concentrically surrounds the internal cryogen delivery conduit and also extends between and is fixed at opposite ends to the two endpieces. The outer conduit has an insulative portion, with the insulative portions of the internal cryogen delivery conduit and the outer conduit electrically insulating the first endpiece from the second endpiece. An annular space between the internal cryogen delivery conduit and the coaxial outer conduit is subject to vacuum pressure via a pumping passage within one of the endpieces which connects to that annular space and which may be connected to a pump for providing the vacuum within that space. Fins are disposed about the periphery of the coaxial outer conduit.

Abstract: The present invention provides a connection for feeding electricity to a transposed superconductive coil, the coil being placed in a cryostat and comprising a plurality of identical superconductive conductors, the free ends of which are distributed uniformly with cylindrical symmetry, the connection being constituted by two current leads each composed of a plurality of identical lead conductors each comprising a first end and a second end, the connection being characterized in that the number of the conductors is identical in each lead and equal to the number of the superconductive conductors in the coil, in that the conductors of the leads are disposed regularly and in parallel with the cylindrical symmetry about the axis of said coil, in that the leads are disposed coaxially and in that the first end of each lead conductor is connected to a respective superconductive conductor.

Abstract: The present invention relates to a superconductive coil assembly which may be used particularly for a current limiter, the coil assembly comprising a plurality of coaxial cylindrical coils electrically connected in series, each coil comprising two windings of superconductive material electrically connected in parallel, arranged coaxially and wound in opposite directions, wherein in each coil, the windings are separated by a material which has a surface resistance in the radial direction lying in the range 10.sup.-5 .OMEGA..m.sup.2 to 10.sup.-2 .OMEGA..m.sup.2 at the temperature of the cryostat, and in which the strands which constitute the superconductive wires may themselves be covered with a layer of the same material.

Abstract: A polymer material which contains ethylene groups and is made fireproof by an organic brominated additive, antimony oxide and optionally a phosphate or pyrophosphate containing titanate. It contains:(a) a non-reticulated polymer matrix containing 40% to 60% by weight of polyethylene and 40% to 60% by weight of a copolymer of ethylene and of alkyl acrylate;(b) 25% to 35% by weight related to the weight of the polymer matrix of the organic brominated additive which is decabromodiphenyloxide, octabromodiphenyl or hexabromodiphenyl;(c) 8% to 19% by weight related to the weight of the polymer matrix of antimony oxide(d) and optionally 0.1% to 0.5% by weight related to the weight of the polymer matrix of an organo phosphate containing a phosphate or pyrophosphate radical.