Radhakrishnan, P; Dr.Sathianandan, K(Cochin University of Science and Technology, April 30, 1985)
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Abstract:
Laser-induced damage is the principal limiting constraint in the design and operation of high-power laser systems used in fusion and other high-energy laser applications. Therefore, an understanding of the mechanisms which cause the radiation damage to the components employed
in building a laser and a knowledge of the damage threshold of these materials are of great importance in designing a laser system and to operate it without appreciable degradation in performance. This thesis, even though covers three distinct problems for investigations using a dye Q-switched multimode Nd:glass laser operating at 1062 nm and emitting 25 ns (FWHM) pulses, lays its main thrust on damage threshold studies on thin films. Using the same glass
laser two-photon excited fluorescence in rhodamine 6G and generation and characterisation of a carbon plasma have also been carried out. The thesis is presented in seven chapters.
Description:
Department of Physics, Cochin university of Science and Technology
Vijayakumar,A; Dr.Thrivikraman, T(Cochin University of Science and Technology, July , 1985)
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Abstract:
This thesis is an attempt to initiate the development of a discrete geometry of the discrete
plane H = {(qmxo,qnyo); m,n e Z - the set of integers}, where q s (0,1) is fixed and (xO,yO) is a fixed point in the first quadrant of the complex plane, xo,y0 ¢ 0. The discrete plane was first considered by Harman in 1972, to evolve a discrete analytic function theory for geometric difference functions. We shall mention briefly, through various sections, the principle
of discretization, an outline of discrete a alytic function theory, the concept of geometry of space and also summary of work done in this thesis
Description:
Department
of Mathematics and Statistics,Cochin University of Science & Technology
Ajithkumar, C M; Dr.Babu, Joseph K(Cochin University of Science and Technology, 1986)
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Abstract:
In 1931 Dirac studied the motion of an electron in the field of a magnetic monopole and found that the quantization of electric charge can be explained by postulating the mere existence of a magnetic monopole. Since 1974 there has been a resurgence of interest in magnetic monopole due to the work of ‘t’ Hooft and Polyakov who independently observed that monopoles can exist as finite energy topologically stable solutions to certain spontaneously broken gauge theories. The thesis, “Studies on Magnetic Monopole Solutions of Non-abelian Gauge Theories and Related Problems”, reports a systematic investigation of classical solutions of non-abelian gauge theories with special emphasis on magnetic monopoles and dyons which possess both electric and magnetic charges. The formation of bound states of a dyon with fermions and bosons is also studied in detail.
The thesis opens with an account of a new derivation of a relationship between the magnetic charge of a dyon and the topology of the gauge fields associated with it. Although this formula has been reported earlier in the literature, the present method has two distinct advantages. In the first place, it does not depend either on the mechanism of symmetry breaking or on the nature of the residual symmetry group. Secondly, the results can be generalized to finite temperature monopoles.
Description:
Department of Physics, Cochin University of Science and Technology
George, Peter; Dr.Joy, George(Cochin University Of Science And Technology, July 11, 1986)
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Abstract:
Over the past years there has been considerable interest in the
growth of single crystals both from the point of view of basic research
and technological application. With the revolutionary emergence
of solid state electronics which is based on single crystal technolo8Ys
basic and applied studies on crystal growth and characterization
_have gained a-more significant role in material science. These studies
are being carried out for single crystals not only of semiconductor
and other electronic materials but also of metals and insulators.
Many organic crystals belonging to the orthorhombic class exhibit
ferroelectric, electrooptic, triboluminescent and piezoelectric properties.
Diammonium Hydrogen Citrate (DAHC) crystals are reported to
be piezoelectric and triboluminescent /1/. Koptsik et al. /2/ have
reported the piezoelectric nature of Citric Acid Monohydrate (CA)
crystals. And since not much work has been done on these crystals,
it has been thought useful to grow and characterize these crystals.
This thesis presents a study of the growth of these crystals
from solution and their defect structures. The results of the microindentation and thermal analysis are presented. Dielectric, fractographic, infrared (IR) and ultraviolet (UV) studies of DAHC crystals are also reported
Description:
Department of Physics, Cochin University
of Science and Technology
Pradeep,B; Dr.Joy, George(Cochin University of Science And Technology, November , 1986)
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Abstract:
This thesis deals with the preparation and properties of two compounds of V-II family, viz.
bismuth telluride and bismuth oxide, in thin filmform. In the first chapter is given the resume of
basic solid state physics relevant to the work reported here. In the second chapter the different
methods of thin film preparationtia described. Third chapter deals with the experimental techniques used for preparation and characterization of the films. Fourth chapter deals with the preparation and propertiesof bismuth telluride films. In next four chapters, the preparation and properties of bismuth oxide films are discussed in detail. In the last chapter the use of Bi205 films in the fabrication of Heat mirrors is examined and discussed.
Description:
Department of physics, Cochin University of Science And Technology
Jacob,M J; Dr.Krishnamoorthy,A(Cochin University Of Science And Technology, 1987)
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Abstract:
In this thesis we attempt to make a probabilistic
analysis of some physically realizable, though complex,
storage and queueing models. It is essentially a mathematical
study of the stochastic processes underlying
these models. Our aim is to have an improved understanding
of the behaviour of such models, that may widen their
applicability. Different inventory systems with randon1
lead times, vacation to the server, bulk demands, varying
ordering levels, etc. are considered. Also we study some
finite and infinite capacity queueing systems with bulk
service and vacation to the server and obtain the transient
solution in certain cases. Each chapter in the thesis is
provided with self introduction and some important references
Description:
Department of Mathematics and Statistics
Cochin University of Science and
Technology
Palson,T I; Dr.Joy, George(Cochin University Of Science And Technology, February 16, 1987)
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Abstract:
The work reported in this thesis is the preparation,
and the structural, electrical and optical properties
of reactively evaporated lead sulphide and tin telluride
thin films. The three temperature method had been used
for the preparation of these semiconductor thin films.
In this preparation technique constituent elements are
evaporated from separate sources with the substrate kept
at a particular temperature. when one of the constituent
element is a gas near room temperature, the method is
often called reactive evaporation. It has been found for
many materials that a stoichiometric interval exists with
a limited range of flux and substrate temperature. Usually
this technique is used for the preparation of thin films of
high melting point compounds or of materials which decompose
during evaporation. Tin telluride and lead sulphide are
neither high melting point materials nor do they decompose
on melting. But even than reactive evaporation offers the
possibility of changing the ratios of the flux of the constituent
elements within a wide range and studying its
effect on the properties of the films
Description:
Department of Physics, Cochin
University of Science and Technology
Annam,Chacko P; Dr.Madhavan Pillai, P(Cochin University of Science and Technology, May , 1987)
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Abstract:
Strychnine, the major alkaloid present in Strychnos nuxvomica seeds has been reported to stimulate the entire central nervous system with preference for the spinal cord. It is a powerful convulsant and because of this property, it is an important pharmacological tool as it plays a unique role as an inhibitor of post synaptic inhibitory impulses. It is useful to study inhibitory
transmitter and receptor types. However, because of its extreme toxicity, strychnine does not have any therapeutic application in the Western system of medicine. The present work was undertaken with a view to obtaining strychnine derivatives having CNS stimulating properties but with sufficiently low toxicity so that they may eventually find some application in medicine. As strychnine is isolated from the locally available strychnos Nugvomica seeds, it’s possible utilization in therapeutics will have considerable commercial significance. This work tries to provide several new compounds which are significantly less toxic than strychnine and its N—oxide as shown from the pharmacological Studio As they also possessed CNS stimulating properties, they are well suited for further screening to assess their potential as valuable therapeutic agents.
Description:
Department of Applied Chemistry, Cochin University
of Science and Technology
Satheesh, Kumar M K; Dr.Girijavallabhan,C P(Cochin University of Science and Technology, August 27, 1987)
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Abstract:
The discovery of the Photoacoustic (PA) effect was a remarkable
achievement and was relegated to the scientific footnotes of the nineteenth
century. However, after the advent of lasers and sophisticated
electronics this effect was rediscovered and it has established itself
as an important research and analytical tool in numerous areas, including
physics, chemistry, biology and medicine. Quite recently, this phenomenon
has made its impact in the field of laser technology for applications
such as the developments of highly efficient active media for
lasers, high quality optics and sensitive laser power monitoring devices.
This thesis presents the work carried out by the author in this field
during the past few years at the Department of Physics in Cochin University
of Science and Technology.
The studies discussed here are mostly based on the development
of a sensitive PA laser power meter and its various applications using
different laser systems available in the laboratory. This includes the
development of a current regulated CW C0 laser and its application
in material processing. The thesis contains seven chapters which by and large are self
contained with separate abstracts and references. The first chapter
which is divided into two parts presents an introduction to the PA effect
and its present status. Part A reviews the basic theory of laser and
gives a sum mary of various lasers and their applications. Part B presents
a brief description of PA effect and its suitability as a spectroscopic
tool followed by its applications to various branches of science and
technology.
Description:
Department of Physics, Cochin
University of Science and Technology