No abstract

From electrical and optical data, the energy gap vereus composition for Zn,Hgl-,Te system is given. The deviation from the linearity is explained as an effect of the change of the covalent radii of the Zn, Hg, and Te atoms.On prhsente la variation de la bande interdite en fonction de la composition pour les alliagesZn,Hgi -,Te, obtenue B l'aide des mesures Bectriques et optiques. La deviation de la linharite est expliquee comme l'effet du changement des rayons covalents des atomes de Zn, Hg et Te.

Measurements have been made of the diffusion coefficient of Cs2+ ions in caesium vapours using a time-of-flight technique with a pulsed ion source and hot-wire detector. This allowed a direct evaluation of the normalized zero electric field mobility of μ0similar, equals0·28 cm2 V−1 S−1 over the approximate temperature range 500-590°K.

A grid-type cathode through which plasma from another discharge could be diffuscd has been used to simulate a heated cathode. Under certain conditions 'identical ' volt-ampere characteristics of a low-voltage arc type have been obtained for both discharges. From this identity an equivalence of all processes a t both cathodes can be assumed.The resulting equations can be used to obtain new data on the physical processes a t the cathode in electrical discharges.

A lot of papers were published by different authors on positive column with the purpose to explain the constriction phenomena. There are niany proposed mechanisms to explain surprisingly well one and the same phenomenon - the positive column constriction