Santhakumari, B; Dr.Krishna Pillai, M G(Cochin University of Science And Technology, 1976)
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Abstract:
This thesis deals with some studies in molecular mechanic using spectroscopic data. It includes an improvement in the parameter technique for the evaluation of exact force fields, the introduction of a new and simple algebraic method for the force field calculation and a study of asymmetric variation of bonding forces along a bond.
Description:
Department of physics, Cochin University of Science And Technology
Sasidharan, Nair S; Dr.Babu, Joseph K(Cochin University of Science and Technology, 1977)
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Abstract:
The present thesis deals with some studies in molecular dynamics using spectroscopic data. Two new approximation procedures the variable method and the average bonding energy criterion have been developed for a reliable calculation of molecular force fields and applied to several molecular species belonging to the xy2 type.
Description:
Department of Physics, Cochin University of Science & Technology
Sabir, M; Dr.Babu, Joseph K(Cochin University of Science and Technology, 1978)
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Abstract:
The present thesis deals with the studies on certain aspects of pathological higher field theories .It brings to light some new abnormalities and new samples of abnormal theories and also puts forward a novel approach towards the construction of trouble free theories
Description:
Department of Science, Cochin University of Science and Technology
Mathew, K T; Dr.Gopalakrishnan Nair, K(Cochin University of Science And Technology, May , 1978)
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Abstract:
In the present thesis, possibility of beam shaping of sectoral horns and corner reflector systems'has been studied in detail. The experimental results obtained in the above two cases are compared. As far as the flanged sectoral horns are concerned, the special advantage is that the gain is increased without impairing impedance conditions. An intense study on corner reflector antennas shows that the been broadening or focussing will be possible by adjusting parameters
involved. Beam tilting by imposing asymmetries is another interesting property of the systems. A comprehensive study of these fields has been presented in Chapter II. Chapter III is exclusively for describing the experimental techniques used in the present investigation.
In Chapter IV, experimental results on flanged sectoral horns and corner reflector eyetses are presented. A comparative analysis of the experimental results obtained with flanged sectoral horns and corner reflector systems is presented in the Chapter V. The similarity and close resemblance in each aspects are shown by presenting typical results from these two eysteee.
Theoretical aspects of both types of antennas are considered in Chapter VI. Attempts are made for co-ordinating the theoretical aspects and drawing a final conclusion. In Chapter VII. the final conclusion that the flanged sectoral horn may be considered as a corner reflector system has been drawn. The importance of the conclusions and usefulness are pointed out. The scope for further
work in these lines has been indicated.
Description:
Department of physics, Cochin University of Science And Technology
Annie,Joseph Vallamattom; Dr.Krishna Pillai, M G(Cochin University of Science And Technology, November , 1978)
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Abstract:
This thesis is divided into two parts. The first part deals with some studies in molecular mechanics Using spectroscopic data and has four chapters in it. Certain approximation methods for the evaluation of molecular force fields are herein developed The second part, which consists of the last two chaptcrs, deals with infrared spectral studies of ternary liquid systems and a polymer film prepared by glow discharge method.
Description:
Department of physics, Cochin University of Science And Technology
Joy, E C; Dr.Joy, George(Cochin University Of Science And Technology, March 27, 1980)
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Abstract:
This thesis consists of a study of the effect of electrode films and overlayer films on the electrical properties of certain metal films. The films have been prepared on glass substrates by thermal evapouration in a vaccum 10 terr. The properties of Al films on Ag, Al,Au and Cu films on In electrodes ,and Bi/Ag bilayer films have been studied. The influence of annealing electrodes at higher temperature on the electrical properties of metal films has also been investigated. Further the effect of varying layer thickness in the bilayer films ,both annealed at higher temperature and annealed at room temperature have been examined.
Description:
Department Of Physics,Cochin University Of Science And Technology
Premachandran,S K; Dr.Joy, George(Cochin University of Science And Technology, January , 1981)
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Abstract:
The thesis presents the results of the investigations on the crystallisation ‘behaviour, detect
structure end electrical properties of certain organic crystals---phthslic snhydride end potsssiun scid phthalate Hollow crystals of phthalic snhydride were grown from vapour. the norpholog of these hollow crystals were studied in detail and s. mechanism for their growth has been proposed. A closed crystal—vapour system was used to study the basal plane growth of the
whiskers and the sequential growth, observed, confirmed the mechanism suggested for hollow crystals. The dendritic crystals of phthslic enhydride were grown, both iron
the melt and solution. The observed morphologies of these dendrites ere described. Bpherulites of phthalic anhydride have been grown by the artificial initiation of nucleation, from melt and solution. The variation of the substructure oi’ these spherulites with the growth tenperature wee
investigated. The spherulitic filll having ribbon substructure were etched to reveal dislocations. A mechanism for the formation of the observed etch pattern has been suggested. the slip occurring in these ribbons were studied and the results are presented
Description:
Department of physics, Cochin University of Science And Technology
Radhakrishnan, M K; Dr.Joy, George(Cochin University of Science And Technology, February , 1981)
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Abstract:
The Thesis consist of the study of the electrical properties of antimony trisulphide films and the electrical behaviour of different metal contacts to antimony trisulphide films. Since the thermal evapouration of the compound antimony trisulphide as such mayresult in nonstoichiometric compound films , sb2s3 films in the present work were mostly prepared by the three temperature method ,keeping the substrate at different temperature ranging from 3031 to 4231 and evapourating antimony and sulphur simultaneously from separate sources.
Description:
Department of Physics, Cochin University of Science And Technology
Subhash, N; Dr.Sathianandan, K(Cochin University of Science And Technology, August , 1981)
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Abstract:
Laser engineering is an area in which developments in the
existing design concepts and technology appear at an alarming rate.
Now—a-days, emphasis has shifted from innovation to cost reduction
and system improvement. To a major extent, these studies are aimed
at attaining larger power densities, higher system efficiency and
identification of new lasing media and new lasing wavelengths. Todate
researchers have put to use all the ditferent Forms of matter as lasing
material. Laser action was observed For the first time in a gaseous
system - the He-Ne system. This was Followed by a variety of solidstate
and gas laser systems. Uarious organic dyes dissolved in suitable
solvents were found to lase when pumped optically. Broad band
emission characteristics of these dye molecules made wavelength tuning
possible using optical devices. Laser action was also observed in
certain p-n junctions of semiconductor materials and some of these
systems are also tunable. The recent addition to this list was the
observation of laser action from certain laser produced plasmas.
The purpose of this investigation was to examine the design
and Fabrication techniques of pulsed Nitrogen lasers and high power
Nd: Glass laserso Attempt was also made to put the systems developed
into certain related experiments
Description:
Department of Physics, Cochin University of Science and Technology
Zachariah,E J; Dr.Nair, K G(Cochin University of Science And Technology, August , 1981)
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Abstract:
The need for improved feed systems for large reflector antennas employed in Radio Astronomy and Satellite tracking spurred the interest in horn antenna research in
the 1960's. The major requirements were to reduce spill over, cross-polarisation losses,and to enhance the aperture efficiency to the order of about 75-8O%L The search for such a feed culminated in the corrugated horn. The corrugat1e 1 horn triggered widespread interest and enthusiasm, and a large amount of work(32’34’49’5O’52’53’58’65’75’79)has already been done on this type of antennas. The properties of corrugated surfaces has been investigated in detail.
It was strongly felt that the flange technique and the use of corrugated surfaces could be merged together to obtain the advantages of both. This is the idea behind the present work. Corrugations are made on the surface of flange elements. The effect of various corrugation parameters are studied. By varying the flange parameters, a good amount of data is collected and analysed to ascertain the effects of corrugated flanges. The measurements are repeated at various frequencies, in the X— and S-bands. The following parameters of the system were studied: (a) beam shaping (b) gain (c) variation of V.S.U.R. (d) possibility of obtaining circularly polarised
radiation from the flanged horn. A theoretical explanation to the effects of corrugated flanges
is attempted on the basis of the line-source theory. Even though this theory utilises a simplified model for the calculation of radiation patterns, fairly good agreement between the computed pattern and experimental results are observed.
Description:
Department of physics, Cochin University of Science And Technology
Sreedharan Nair, M N; Dr.Babu, Joseph K(Cochin University of Science and Technology, November 2, 1981)
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Abstract:
This thesis is devoted to theoretical studies on the properties of hadrons on the basis of bag models. It contains some applications of the traditional.HIT bag model to the spectroscopy and decay of hadrons. The inadequacies of the model are brought out and a new version of the model, called the variable pressure bag model, is developed. Some of the Phenomenological applications of this model are discussed and the predictions are compared with experiment.
Description:
Department of Physics, Cochin University of Science & Technology
Sebastian, P J; Dr.Sathianandan, K(Cochin University Of Science And Technology, November 25, 1981)
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Abstract:
Eventhough a large number of schemes have been proposed and develoned for N9 laser ouined dye lasers the
relatively low efficiency compelled the scientists to
device new methods to improve the system efficiencs.
Energy transfer mechanism has been shown to he a convenien
tool for the enhancement of efficiency of dye lasers. Th
p resent work covers a detailed study of the performance
characteristics of a N2 laser pumped dye laser in the con—
ventional mode and also, when pumped by the energy transfer
mechanism. For .th.e present investigations a dye laser
pumped by a'N2 laser (A4200 kw peak power) was fabricated.
The grating at grazing incidence was used as the beam expanding
device; A t its best performance the system was
giving an output peak power of l5 kW for a 5 X lC"3H/l Rh—€
solution in methanol. T he conversion efficiency was 7.5;
The output beam was having 3 divergence of 2 mrad and bandwidth
o.9 A. Suitable modifications were suggested for
obtaining better conversion efficiency and bandwidth.
Description:
Department of Physics,
Cochin University Of Science And Technology
Syamaprasad, U; Dr.Girijavallabhan,C P(Cochin University of Science And Technology, December , 1981)
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Abstract:
The thesis aims to present the results of the
experimental investigations on the electrical properties like
electrical conductivity, dielectric constant and ionic thermo~
currents in certain ammonium containing ferroelectric crystals
viz. LiNH4SO4, (NH4)2SO4 and (NH4)5H(SO4)2. Special attention
has been paid in revealing the mechanisms of electrical conduction
in the various phases of these crystals and those asso~
ciated with the different phase transitions occurring in them,
by making studies on doped, quenched and deuterated crystals.
The report on the observation of two new phase transitions in
(NH4) S O2 and of a similar one in ( NH4 ) H (2SO4 ) are included. The relaxation mechanisms of the impurity-vacancy complexes and the space charge phenomena in pure and doped crystals of LiNH4SO4 and (NH4)2SO4 and the observation of a new type of ionic thermo-current viz. Protonic Thermo-Current (PTC) in these crystals are also presented here.
Description:
Department of Physics, Cochin University of Science and Technology
Raveendran Nair, B; Dr.Joseph,Francis D(Cochin University of Science and Technology, December , 1981)
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Abstract:
Urea-formaldehyde resins find numerous
applications in adhesive, textile finishing and moulded
plastic industries. Kinetic investigations of the reactions of
urea and its related compounds with formaldehyde in
aqueous acid, alkaline and neutral media have been carried
out. A thin—layer chromatographic method was developed
for the separation and estimation of the products of these
reactions. Using this technique the various initial steps
in the reactions were analysed and the rate constants have been determined.
Description:
Department of Applied Chemistry, Cochin University of Science and Technology
Nirmala, Paul; Dr.Krishna Pillai, M G(Cochin University Of Science And Technology, December 2, 1981)
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Abstract:
The thesis is a report of the attempts made to
prepare semiconducting and dielectric thin films and to
study their electrical properties. It consists of (i)
studies on the preparation and electrical characteristics
of compound semiconductor thin films of silver sulphide
and ferric hydroxide, and (ii) investigations on the electrical
and dielectric properties of plasma polymerized
thin films of para-toluidine element
Description:
Department
of Physics,Cochin University Of Science And Technology