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The pure rotational spectra of HCl mixed with argon, krypton and xenon gas of varying pressures at different temperatures have been measured. From the linewidths and shifts the cross sections can be calculated as a function of the temperature. With the insertion of a Boltzmann distribution of translational energy the temperature dependence can be converted to a dependence of the cross section σ( E ) on the relative kinetic energy of the colliding pairs. A comparison of the experimentally determined σ( E ) values with the values predicted by a semi-classical calculation by Neilsen and Gordon leads to the conclusion that the elastic contribution to the cross sections remains of importance even at energies so high that the inelastic contribution has become constant because of the attainment of the sudden perturbation limit. Furthermore it must be concluded that the coefficient of the first Legendre polynomial in the series development of the attractive anisotropic potential is considerably larger than has hitherto been assumed.

This Symposium on the technological aspects of fusion research attracted approximately 230 participants, the majority having arrived from countries in Europe, including the Soviet Union, while others were from plasma physics laboratories, reactor centres, universities, and industries in USA, Canada, Japan, and Israel.

Synopsis Until now the compressibility of a water/air mixture has been calculated with the aid of Boyle's law and Henry's law of solubility; it has been assumed that the air and water pressures of the mixture were the same. The present treatment refers only to degrees of saturation in excess of 85% where the air is assumed to be present in the form of bubbles. It is necessary to take into account the surface tension between air and water in the calculation of the compressibility of the mixture. Also using the surface tension and the above laws it is possible to obtain a relation between air and water pressures. Formulae are given by which it is possible to predict the water pressure of partly saturated clay samples in the triaxial cell under different stress conditions. Jusqu'à maintenant la compressibilité d'un mélange air et eau avait été calculée en utilisant la loi de Boyle et la loi de Henry régissant la solubilité. On prenait comme hypothése que la pression de l'air était égale à la pression d'eau dans le mélange. L'essai présent rend compte seulement du degré de saturation plus que 85%; il est assumé quele mélange consiste non pas de deux phases bien distinctes, mais d'une série de bulles d'air distribuées dans le liquide. On doit tenir compte des forces de tension de surface pour calculer la compressibilité du mélange. Ainsi tenant compte des forces de tension de surface et des lois précédemment mentionées, on peut établir une relation entre la pression de l'air et la pression de l'eau. L'article donne les formules qui permettent de prédire la pression interstitielle d'échantillons d'argiles partiellement saturées dans un essai triaxial.

The maximum ion or electron current that can be transmitted by an element of an infinitely periodic system of uni-potential lenses is investigated. The complexity of the problem renders an exact analytical treatment impossible. However, with some simplification it is possible to derive formulae for the maximum transmitted current and the increase of the beam diameter in the midplane of the lens. Numerical examples are given which show how current and beam amplitude depend on the lens voltage and on the geometry of the electrode configuration. Finally, the analysis proves to be in agreement with a step by step calculation of the trajectory of a boundary particle, carried out for one particular case.

The decays of two states of 82As are reported: 82aAs with T 1 2 = 19±1.5 and 82bAs with T 1 2 = 13.0±0.6 s . Information on the decay of 79Ge with T 1 2 = 40±4 s was also obtained. Spectra of single β- and γ-rays, γγ and βγ coincidence measurements and fast chemical separations were used to identify and to study the decays of these activities, particularly of 82a+82bAs. The two isomers of 82As probably have spin and parity l+(a) and 5−(b). From their decays levels are proposed in 82Se at: 654.8(2+), 1731.2(2+), 1735.4(4+), 2550.8(3+), 2894.2(4−), 3454(5−), 4091, (4321) and (4565) keV. An unusually large hindrance factor of the allowed β-decay from the 1+ state of 82aAs is noted. The partial decay scheme of 79Ge has levels in 79As at 230.4 and 772.9 keV and possibly at 985.9 keV.