Showing papers in "Indian Journal of Pure & Applied Physics in 1990"

Poisson's ratios in cubic crystals corresponding to (110) loading

Abstract: The existence of negative values for the Poisson's ratio, υ 110 corresponding to (110) loading to cubic crystals has been investigated. It is observed that crystals having negative values of υ 110 must satisfy an inequality involving the elastic constants. Ordinarily, crystals with large values for the anisotropy parameter A=2 c 44 /(c 11 -c 12 ) are the most likely members to have negative values of υ 110 . Such crystals include the rare gas solids and most metals. The analysis suggests that the role of conduction electrons in metals may be vital in determining whether or not a particular metal will have negative values of υ 110

CCD image data acquisition system for optical astronomy.

Abstract: Un systeme complet de traitement d'images base sur le dispositif CCD a ete developpe a TIFR, Bombay, pour l'utilisation dans le programme d'astronomie optique de l'institut. Le dispositif CCD comme un systeme imageur et ses avantages par rapport a la plaque photographique conventionnelle sont brievement passes en revue. Le systeme d'acquisition des donnees est decrit en detail

Rotational analysis of 2πi→2Δi system of NiCl

Abstract: Determination pour la premiere fois des constantes moleculaires, des etats superieurs et inferieurs. Observation des effets isotopiques dus a 37 Cl et du dedoublement de type lambda dans l'etat superieur 2 π

Performance evaluation of a luminescent solar concentrator with a liquid polymer matrix

Abstract: Luminescent dyes dissolved in solid PMMA matrix have been used in the conventional non-tracking concentators of solar energy. The present paper describes the performance of a concentrator with liquid polymer. Tween-80 as a solvent medium for luminescent dyes. A set of four luminescent dyes has been characterised in Tween-80, and the optical efficiencies of the liquid concentrator using the dye solutions have been studied