Abstract: The method for controlling the migration of an electronegative chemical species within a solid substrate which exhibits ionic conduction consists in irradiating the substrate with electrons which have sufficient energy to penetrate into the substrate and to produce therein metastable excited negative ions of said species and in applying to said substrate an electric field having a direction opposite to the desired direction of migration.

Abstract: A process of elementary and chemical analysis of samples by spectrum analysis of secondary electrons emitted by the sample when it is subjected to a beam of monoenergetic primary electrons concentrated on its surface is characterized in that the intensity of a beam of monoenergetic primary electrons E.sub.p emitted by an electron gun is modulated according to a sinusoidal law at a frequency .omega., in that the secondary electrons of energy E emitted by the sample are collected, in that the intensity of the collected beam is detected by generating an electric detection signal proportional to the intensity, in that the intensity of the component of the frequency .omega. of the detection signal which provides the number of secondary electrons corresponding to the said energy is measured, and, in that the value of the collection energy E is modified in order to scan the energy spectrum comprised between the values E.sub.1 and E.sub.

Abstract: An electroemissive component having variable emissivity is made up of a conductive substrate on which at least one continuous thin film of a solid organometallic compound has been formed by electrochemical deposition and of a conductive deposit constituted by at least one thin film and deposited on said organometallic film, the substrate and the conductive deposit being electrically connected respectively to the two poles of a variable-voltage source which controls the emissivity.The component is particularly well suited to the fabrication of electronic or optoelectronic devices such as electron tubes, luminescent cells, display panels, thin television screens, and brightness amplifiers.