Abstract: Thermal analysis method, particularly for determining the heat capacity of body, or its derivative with respect to temperature, or a latent heat, said method comprising differential measurement of a physical parameter between two samples (84, 84?) undergoing a temperature change under equivalent conditions, said method being characterized in that said samples are essentially identical as to composition and thermal properties and exhibit, at the start of the measurement, an initial temperature difference of known magnitude. Apparatus for carrying out such a method.

Abstract: The device includes a first body (1) of superconducting material placed in the magnetic field to be measured, an arrangement (7) suitable for successively changing the temperature of this first body above and below its transition temperature, at a first frequency, so as to generate field variations in the vicinity of the body, and an arrangement for determining the field from these variations. The arrangement includes a second body (4) of superconducting material, placed in the vicinity of the first body (1), an optical fiber (8) suitable for changing the temperature of at least one portion of this second body, above and below its transition temperature, at a second frequency greater than the first frequency, in order to generate, in this second body, current variations proportional to the field variations. These current variations are then measured and the field is determined from these variations.

Abstract: This device for converting a very-low-amplitude steady voltage signal into an alternating voltage signal, of the type comprising a centre-tapped transformer (1) associated with a transistor (3,4) chopper (2), is characterised in that the transformer (1) and the transistors (3,4) are arranged in a housing (15) held at very low temperature and in which is arranged a material (20) for thermal insulation of the transistors (3,4) with respect to the rest of the housing so as to reduce temperature fluctuations and allow operation of these transistors by self-heating due to their drive current.

Abstract: Ceramic superconductor materials, e.g., of rare earth/alkaline earth metal/transition metal/oxygen type, contain an effective stabilizing amount of fluorine atoms distributed therein in a concentration gradient decreasing from the external face surface of the material to the core region thereof; advantageously the fluorine atoms are principally distributed in an external protective diffusion barrier layer.

Abstract: Ceramic superconductor materials, e.g., of rare earth/alkaline earth metal/transition metal/oxygen type, contain an effective stabilizing amount of fluorine atoms distributed therein in a concentration gradient decreasing from the external face surface of the material to the core region thereof; advantageously the fluorine atoms are principally distributed in an external protective diffusion barrier layer.

Abstract: In a process for making a connection between superconductive wires constituted by one or more strands or filaments of superconductive material embedded in a metallic matrix, the metal constituting the matrix is previously eliminated over a certain length of wire, corresponding to the desired zone of contact between the wires, so as to expose the or each strand of these wires. Thereafter the linkage is established between the strands by exerting thereon a strong pressure, cold.The visible superconductive strands of the two wires are applied, near one another, on a support. A strip of superconductive material is then applied on the visible strands and a sheath made of a material which is a good conductor of electricity is placed around the assembly constituted by the support, the strands of the superconductive wires and the superconductive strip.

Abstract: Apparatus for electrically chopping a direct current signal by controlling the superconductivity state of resistance elements contained within a cryostat. The resistance elements are in a bridge arrangement and the control is provided by laser diodes also contained within the cryostat.