Phase Separation of Rigid-Rod Suspensions in Shear Flow

We analyze the behavior of a suspension of rigid rod-like particles in shear flow using a modified version of the Doi model, and construct diagrams for phase coexistence under conditions of constant imposed stress and constant imposed strain rate, among paranematic, flow-aligning nematic, and log-rolling nematic states. We calculate the effective constitutive relations that would be measured through the regime of phase separation into shear bands. We calculate phase coexistence by examining the stability of interfacial steady states and find a wide range of possible ``phase'' behaviors.Comment: 23 pages 19 figures, revised version to be published in Physical Review

FORCED AUTOIONIZATION OF THE Ba 5d7d STATE

Nous avons fait l'étude de l'interaction entre l'état 5d7d 1D2 situé à 200 cm-1 en dessous de la première limite d'ionisation du barium avec la série de Rydberg 6snd. Nous décrivons l'étude de l'interaction de l'état 5d7d avec le continuum Stark produit par des champs électriques de 5 kV/cm.We report the study of the interaction of the Ba 5d7d 1D2 state lying 200 cm-1 below the first ionization limit with the 6snd Rydberg series in which it is embedded. Specifically we describe the study of the interaction of the 5d7d state with the Stark continuum produced by electric fields of ~ 5 kV/cm