Study of effects of dopants on structure of vitreous semiconductors (GeSe3.5)100-xMx (M = Bi,Sb) using high pressure techniques

An investigation of the problem of controlled doping of amorphous chalcogenide semiconductors utilizing a Bridgman anvil high pressure technique, has been undertaken. Bulk amorphous semiconducting materials (GeSe_3.5)_100-x doped with M = Bi (x = 2, 4, 10) and M = Sb (x = 10) respectively are studied up to a pressure of 100 kbar down to liquid nitrogen temperature, with a view to observe the impurity induced modifications. Measurement of the electrical conductivity of the doped samples under quasi-hydrostatic pressure reveals that the pressure induced effects in lightly doped (2 at % Bi) and heavily doped (x = 4, 10) semiconductors are markedly different. The pressure effects in Sb-doped semiconductors are quite different from those in Bi-doped material.     

On the classical solution of SO(3) gauge theory and ’t Hooft-Polyakov monopole

It is shown that the ansatz for the asymptotic (r → ∞) gauge fields used by ’t Hooft in the study of monopoles in SO(3) electroweak theory is not unique.     

Existence of stationary equilibrium strategies in non-zero sum discounted stochastic games with uncountable state space and state-independent transitions

Non-zero sum discounted stochastic games with uncountable state space and state in-dependent transitions have stationary equilibrium strategies.     

Magnetic monopoles in SU(3) and SU(2) gauge theories without Higgs' scalars

We show that certain known singular solutions for pure SU(3) Yang-Mills theory carry magnetic charges with respect to both U(1) subgroups of SU(3). A topological characterisation in terms of monopoles is given to the SU(2) singular solutions of Wu and Yang.     

Relation between efficiency of quartz transducers and ultrasonic absorption coefficient of liquids. II

On the basis of the investigation carried out in this Laboratory, a relationship has been worked out between the absorption coefficient of a liquid and the overall efficiency of a quartz transducer vibrating in that medium in Part I of the paper. In this paper a similar relationship is established between the absorption coefficient of the liquid and the net ultrasonic efficiency of the crystal.     

On stochastic games,II

In this paper, we consider positive stochastic games, when the state and action spaces are all infinite. We prove that, under certain conditions, the positive stochastic game has a value and that the maximizing player has an -optimal stationary strategy and the minimizing player has an optimal stationary strategy.The authors are grateful to Professor David Blackwell and the referee for some useful comments.     

Topotaxy in the oxidation of valentinite,Sb2O3, to cervantite,Sb2O4

The oxidation of orthorhombic Sb₂O₃, valentinite, to orthorhombic Sb₂O₄, cervantite, has been shown by single crystal x-ray diffraction techniques to be a topotactic reaction. The orientation relationships between the two lattices have been determined by making use of a hybrid crystal. It has been found that the individual axes in the two oxides are parallel. The two crystal structures have been compared in the appropriate orientation and their close similarity has been established. The shifts of the individual atoms in valentinite during the process of oxidation have been calculated to be not more than 0·6 Å. It has been established that the reduction of cervantite to valentinite also takes place topotactically.