Abstract: A heat transmission apparatus is formed between a thermal source (12) and an object (21) in a vacuum enclosure (1) by placing in a cavity defined by a heat emission wall (20) and the object (21), a granular material (30) which adapts to the thermal expansions, while permitting heating by conductivity under very good conditions.Possible application to the manufacture of semiconductors and the crystallization of thin films.

Abstract: A resistor for the treatment of materials, such as for the production of monocrystals by the planar resistor method includes an electrically conductive thin plate having a zone with a plurality of holes. With respect to an electric current flowing in the plate substantially parallel to its faces, the plate has lower electrical resistance in a peripheral area of said zone than in the central portion thereof.

Abstract: These lasers in particular have two flashlamps (30, 32) for longitudinally pumping a monocrystalline aluminate bar (28) emitting in the visible and near infrared, two mirrors (38, 40) for amplifying the light emitted by the bath, a polarizer prism (42) used for feeding the amplified light beam to the outside of the laser cavity. The magnetoplumbite-type aluminate has in particular the formula:La.sub.1-x Mg.sub.1-y-z Mt.sub.v Al.sub.11+x+2y/ 3-v O.sub.19-z(II)in which Mt represents a transition metal chosen from titanium and zirconium; x is a number such that 0<x<0.3; y and z are numbers such that 0.ltoreq.y+z.ltoreq.1 with 0.ltoreq.y.ltoreq.1 and 0.ltoreq.z.ltoreq.1; v is a number such that 0<v<1.