Abstract: Device for estimating, at high temperature, the electromagnetic properties of a material, including:an oven (1, 19, 20);a waveguide (3) disposed at least in part in said oven, a housing for a specimen piece of uniform thickness made of said material, this specimen piece being such that, when it is disposed in said housing, its outer periphery matches the inner surface of the waveguide;means (4, 5, 6) for applying an incident very high frequency electromagnetic wave to the waveguide (3); andmeans (4, 5, 6) for collecting the electromagnetic wave reflected by said specimen piece.A vertically disposed waveguide has (3) said housing provided at the open lower end (3B ).

Abstract: In an optic relay device having a memory the image to be treated is projected on a photoconductive element and is transformed into a charge image stored in a memory in the proximity of a plate of electro-optical material brought at its Curie point.The electro-optical material and the photoconductive element are such that the Curie temperature of the electro-optical material is near the temperature of the maximum sensitivity of the photoconductor.