Rajasree, K; Vidyalal, V; Radhakrishnan, P; Nampoori, V P N; Vallabhan, C P G(IOP, 1993)
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Abstract:
The phenomenon of mirage effect suffered by a He-Ne laser beam has been utilized to detect phase transitions in solids. It has been observed that anomalous fluctuations of large amplitude occur in the signal level near the transition temperature. The mean square value of the fluctuation is found to exhibit a well-defined peak at this point. Results of measurements made in the case of crystals of TGS ((NH2CH2COOH)3.H2SO4) and a ceramic sample (BaTiO3) are given to illustrate this technique.
Rajasree, K; Vidyalal, V; Radhakrishnan, P; Nampoori, V P N; Vallabhan, C P G(American Institute of Physics, August 1, 1993)
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Abstract:
Laser‐induced damage and ablation thresholds of bulk superconducting samples of Bi2(SrCa)xCu3Oy(x=2, 2.2, 2.6, 2.8, 3) and Bi1.6 (Pb)xSr2Ca2Cu3 Oy (x=0, 0.1, 0.2, 0.3, 0.4) for irradiation with a 1.06 μm beam from a Nd‐YAG laser have been determined as a function of x by the pulsed photothermal deflection technique. The threshold values of power density for ablation as well as damage are found to increase with increasing values of x in both systems while in the Pb‐doped system the threshold values decrease above a specific value of x, coinciding with the point at which the Tc also begins to fall.
Ponnachan,P T C; Paulose,C S; Panikkar,K R(Department of Biotechnolgy, 1993)
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Abstract:
Alloxan induced diabetic animal model was
used to evaluate the antidiabetic effect of alkaloids
extracted from the leaves of Aegis marine/ose. The
alkaloid extract maintained the weight of animals
near to that of control ones - whereas there was a
decrease in the body weight of diabetic animals. A
significant increase in blood glucose (342. 14 -+-
14.89 mg/dl) was seen in diabetic animals but in
alkaloid treated group the blood glucose was lowered
(90: 12 +_5.81 mg/dl). There was no decrease in
blood urea arid sreum cholesterol in the alkaloid
treated group of diabetic animals. The liver
glycogen decreased in diabetic animals (1.27+.12
g/100g of wet tissue) and the treatment brought the
glycogen level to that of control ones (2.51 +.75
g/100 g of wet tissue). The result show that the
alkaloid extract has hypoglycaemic activity.