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.
Aanandan,C K; Mohanan,P; Supriyo,Dey; K G Nair(Department of Electronics, 1994)
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Abstract:
A simple technique to improve the impedance bandwidth of a circular
microstrip patch antenna using two sectorial slots is proposed. Using this
design more than 5% impedance bandwidth is obtained. The added
advantage of this new antenna is that it can be fed by a 50 microstrip
line.
Girijavallabhan, C P; V P N Nampoori; Harilal, S S; Riju, C Issac; Bindhu C V(Journal of Physics D : Applied Physics, January 24, 1997)
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Abstract:
Optical emission studies of C2 molecules in plasma obtained by Nd:YAG
laser ablation of graphite in a helium atmosphere are reported for irradiances in the
range (1–9:2/ x 1010 W cm−2. The characteristics of the spectral emission intensity
from the C2 (Swan band) species have been investigated as functions of the
distance from the target, ambient pressure and laser irradiance. Estimates of
vibrational temperatures of C2 species under various irradiance conditions are
made. Results of measurements performed under different ambient helium gas
pressures are also discussed.
Sugunan, S; Kumaree Seena, C R(Indian Journal of Chemistry, May , 1998)
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Abstract:
We have investigated the changes in surface acidity/basicity
and catalytic pro~erties of samarium oxide due to surface modification
by SO42- ion. The acidity/basicity of the catalysts is
determined by titration method using Hammett indicators.
Esterification of acetic acid by n-butanol is chosen as a test
reaction. Sm203, owing to its high basicity and low acidity, does
not catalyze the reaction. But sulphated Sm20J catalyzes the
esterification reaction effectively. Activation temperature does
not have much effect on the acidity of sulphated samaria.
Rani, Joseph(John Wiley & Sons,Inc., December 29, 1997)
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Abstract:
ABSTRACT: The electrical conductivity of silicone rubber vulcanizates containing carbon
blacks [e.g., acetylene black, lamp black, and ISAF (N-234) black] were investigated.
The change in electrical conductivity with varying amounts of carbon blacks and the
temperature dependence was measured. The mechanical properties like tensile
strength, tear strength, elongation at break, hardness, etc., of the vulcanizates were
determined. A comparative study of the electrical conductivity of the composites revealed
that the electrical conductivity of the composites made with acetylene black was
higher than that of the composites made of other blacks.
Rasheed, T M A; Nampoori, V P N(Springer, March , 1994)
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Abstract:
The CH local mode overtone spectrum of benzyl chloride in the visible and NIR regions studied by laser induced thermal lens and conventional NIR absorption is presented. The analysis shows that the −CH2Cl group is symmetrically oriented with respect to the benzene ring, thus finalizing one of the two possible conformational models predicted by electron diffraction studies. The aryl CH bonds have a slightly larger force constant than that in benzene.
Rajasree, K; Ravikumar, A V; Radhakrishnan, P; Nampoori, V P N; Vallabhan, C P G(Springer, April , 1992)
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Abstract:
Photothermal deflection technique was used for determining the laser damage threshold of polymer samples of teflon (PTFE) and nylon. The experiment was conducted using a Q-switched Nd-YAG laser operating at its fundamental wavelength (1-06μm, pulse width 10 nS FWHM) as irradiation source and a He-Ne laser as the probe beam, along with a position sensitive detector. The damage threshold values determined by photothermal deflection method were in good agreement with those determined by other methods.
Thomas, Baby; Nampoori, V P N(Solid State Communications, 1992)
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Abstract:
A method of preparation of strontium sulphide phosphors doped
with europium is given. Nitrogen laser excited fluorescence emission
spectra of these phosphors in the visible region are recorded. A band
with line structure in the region 350-430 nm and a new broad band at
460 nm are observed. The splitting pattern for the 6p levels of Eu 2+ are
given.
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.
Pyroja,S; Biju,M P; Paulose,C S(Department of Biotechnology, February 11, 1998)
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Abstract:
Effect of pyridoxine on growth, metabolism and cellular activity of
freshwater prawn Macrobrachiuni rosenbergii was studied. Postlarvae
(PL-10) of M. rosenbergii were fed with clam meat containing
various concentrations of pyridoxine. After 30 days RNA and DNA
of the abdominal tissues were estimated. Length, weight and RNA
to DNA ratio increased significantly with increasing concentrations
of pyridoxine. The effect of pyridoxine on the metabolic enzyme,
malate dehydrogenase, was also studied. Vmax showed a significant
decrease and the (Km) showed a significant increase in experimental
groups compared to control.