Lalitha, P R; Rao, V R; Nampoori, V P N(Current Science, 1980)
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Abstract:
Excitation and emission spectra of SrS : Mn : Ce phosphors have been studied in detail
at various Mn and Ce concentrations. In order to study the effect of external pressure on phosphors,
the samples were pretreated under various pressures. Four bands around 470 nm, 530 nm,
310 nm and 620 nm were observed, when the samples were excited with 265 nm radiation. The
effect of pressure is to reduce the fluorescence ability of the phosphors, and the luminescence
vanishes above O· 1 ton m-2 pressure. The fluorescence ability, however, can be regained on retiring
the sample. The emission mechanism has been attributed to two luminescentcenters in the forbidden
gap. An appreciable amount of photocurrent has also been observed for the sample.
Lo, H Y; Leung, K W(Microwave and Optical Technology Letters, June 5, 2001)
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Abstract:
A new configuration that employs a conducting conformal
strip to excite the low-profile equilaterial-triangular dielectric resonator
antenna (DRA) of very high permittivity is proposed. As compared with
the previous aperture-coupling configuration, the new configuration has
a wider impedance bandwidth (- 5.5%) and a higher front-to-back
radiation ratio. The return loss, radiation patterns, and antenna gain are
measured and discussed
Kailasnath, M; Nishant, Kumar; Nampoori, V P N; Vallabhan, C P G; Radhakrishnan, P(Elsevier, 2008)
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Abstract:
Dependence of energy transfer parameters on excitation wavelength has been investigated in poly (methyl methacrylate) (PMMA) optical fibre preforms doped with C 540:Rh B dye mixture by studying the fluorescence intensity and the lifetime variations. A fluorescence spectrophotometer was used to record the excitation spectra of the samples for the emission wavelengths 495 and 580 nm. The fluorescence emission from the polymer rods was studied at four specific excitation wavelengths viz; 445, 465, 488 and 532 nm. The fluorescence lifetime of the donor molecule was experimentally measured in polymer matrix by time correlated single photon counting technique. The energy transfer rate constants and transfer efficiencies were calculated and their dependence on the acceptor concentration was analysed for three excitation wavelengths. It was found that any change in the excitation wavelength leads to significant variations in the quenching characteristics, which in turn affect the calculated energy transfer parameters.
Radhakrishnan, P; Nampoori, V P N; Litty, Irimpan; Bindu, Krishnan; Deepthy, A(Journal of Physics D : Applied Physics, August 30, 2007)
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Abstract:
In this paper, the fluorescence behaviour of nano colloids of ZnO has been
studied as a function of the excitation wavelength. We have found that
excitation at the tail of the absorption band gives rise to an emission that
shifts with the change of the excitation wavelength. The excitation
wavelength dependent shift of the fluorescence maximum is measured to be
between 60 and 100 nm. This kind of excitation wavelength dependent
fluorescence behaviour, which may appear to be in violation of Kasha’s rule
of excitation wavelength independence of the emission spectrum, has been
observed for nano ZnO colloids prepared by two different chemical routes
and different capping agents. It is shown that the existence of a distribution
of energetically different molecules in the ground state coupled with a low
rate of the excited state relaxation processes, namely, solvation and energy
transfer, are responsible for the excitation wavelength dependent
fluorescence behaviour of the systems.
Nampoori, V P N; Radhakrishnan, P; Litty, Irimpan; Bindu, Krishnan; Deepthy, A(Journal of Physics D : Applied Physics, August 30, 2007)
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Abstract:
In this paper, the fluorescence behaviour of nano colloids of ZnO has been
studied as a function of the excitation wavelength. We have found that
excitation at the tail of the absorption band gives rise to an emission that
shifts with the change of the excitation wavelength. The excitation
wavelength dependent shift of the fluorescence maximum is measured to be
between 60 and 100 nm. This kind of excitation wavelength dependent
fluorescence behaviour, which may appear to be in violation of Kasha’s rule
of excitation wavelength independence of the emission spectrum, has been
observed for nano ZnO colloids prepared by two different chemical routes
and different capping agents. It is shown that the existence of a distribution
of energetically different molecules in the ground state coupled with a low
rate of the excited state relaxation processes, namely, solvation and energy
transfer, are responsible for the excitation wavelength dependent
fluorescence behaviour of the systems.
Krishnan Nair, P R; Nandakumaran, V M(Springer, October , 1998)
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Abstract:
We present the analytical investigations on a logistic map with a discontinuity at the
centre. An explanation for the bifurcation phenomenon in discontinuous systems is presented. We
establish that whenever the elements of an n-cycle (n > 1) approach the discontinuities of the nth
iterate of the map, a bifurcation other than the usual period-doubling one takes place. The periods of
the cycles decrease in an arithmetic progression, as the control parameter is varied. The system also
shows the presence of multiple attractors. Our results are verified by numerical experiments as well.
Bindhu, C V; Harilal, S S; Nampoori, V P N; Vallabhan, C P G(Springer-Verlag, 2000)
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Abstract:
Optical limiting and thermal lensing studies are
carried out in C70–toluene solutions. The measurements are
performed using 9-ns pulses generated from a frequencydoubled
Nd:YAG laser at 532 nm. Optical limiting studies in
fullerene molecules lead to the conclusion that reverse saturable
absorption is the major mechanism for limiting. Analysis
of thermal lensing measurements showed a quadratic
dependence of thermal lens signal on incident laser energy,
which also supports the view that optical limiting in C70 arises
due to sequential two-photon absorption via excited triplet
state (reverse saturable absorption).
Hunagund,P V; Jose,K A; Mohanan, P; Nair, K G(Indian Journal of Radio & Space Physics, February , 1992)
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Abstract:
Results of exhaustive study of the effect of metallic flanges on H-plane radiation characteristics of V-slot
waveguide antenna are presented . It has been established that the beam can be sharpened or broadened by
varying the flange angle . The adjustment of the flange angle and flange width would further improve the
radiation pattern , yielding optimum efficiency from the flanged system
Subha, V; Savenije, H H G; Van der Zaag, P; Anil, K R; Balan, K(European Geosciences Union, November 10, 2005)
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Abstract:
This paper presents the results of a field experiment conducted in Kerala, South India,
to test the effectiveness of coir geotextiles for embankment protection. In the context
of sustainable watershed management, coir is a cheap and locally available material
5 that can be used to strengthen traditional earthen bunds or protect the banks of village
ponds from erosion. Particularly in developing countries, where coir is abundantly
available and textiles can be produced by small-scale industry, this is an attractive
alternative for conventional methods
Sinu, C R; Vijay, Nair, G; Radhakrishnan, K V(Cochin University of Science And Technology, November 22, 2014)
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Abstract:
The thesis entitled “Exploration of Novel Organic Reactions Catalyzed by
Nucleophilic Heterocyclic Carbenes (NHCs)” embodies the results of the
investigations carried out to explore the synthetic potential of N–heterocyclic carbenes
(NHCs) as organocatalyst towards various electrophiles for the synthesis of heterocyclic
and carbocyclic systems. Recent investigations in the generation of homoenolates by the
addition of NHCs to conjugated aldehydes have made it possible to study the reactivity of
this unique three carbon synthon.
Krishnan Kartha, K; Dr. Ajayaghosh, A(Cochin University Of Science And Technology, January 8, 2014)
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Abstract:
Gelation provides a unique medium, which often induces
organization of molecules resulting in the modulation of their
optical, morphological and electronic properties thereby opening a
new world of fascinating materials with interesting physical
properties at nano- meso- and macroscopic levels. Supramolecular
gels based on linear π-systems have attracted much attention due to
their inherent optical and electronic properties which find
application in organic electronics, light harvesting and sensing. They
exhibit reversible properties due to the dynamic nature of noncovalent
forces. As a result, studies on such soft materials are
currently a topic of great interest. Recently, researchers are actively
involved in the development of sensors and stimuli-responsive
materials based on self-assembled π-systems, which are also called
smart materials.
The present thesis is divided into four chapters
Description:
Photosciences and Photonics
Chemical Sciences and Technology Division
CSIR-National Institute for Interdisciplinary Science and
Technology (CSIR-NIIST), Trivandrum
Hector J,Thayil Kochukunnel; Arunachalam, P(Department of Applied Economics, 2006)
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Abstract:
The study was motivated by the need to understand factors that guide the software exports and competitiveness, both positively and negatively. The influence of one factor or another upon the export competitiveness is to be understood in great depth, which is necessary to find out the industry’s sustainability. India is being emulated as an example for the success strategy in software development and exports. India’s software industry is hailed as one of the globally competitive software industry in the world. The major objectives are to model the growth pattern of exports and domestic sales of software and services of India and to find out the factors influencing the growth pattern of software industry in India. The thesis compare the growth pattern of software industry of India with respect to that of Ireland and Israel and to critically of various problems faced by software industry and export in India and to model the variables of competitiveness of emerging software producing nations
Francis,C A; Dr.Ranganathan, N(Cochin University of Science and Technology, August 6, 1991)
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Abstract:
The main aim of this study is to examine the deficiencies of the export development process and strategy in India and, to suggest, in the light of the findings of the above, measures for improvement. The marine products industry has been chosen as a case for a detailed investigation. The researcher conducts an evaluative study on the export potential for India’s marine products and trends in the international market for marine products. The thesis tries to identify the major hurdles in increasing exports of marine products from India. The evaluation of the adequacy and effectiveness of the measures taken to promote marine products exports is also undertaken
Description:
School of Management Studies, Cochin
University of Science & Technology
Muhamed Kutty, K B; Dr.Chandrasekharan, N S(Cochin University of Science and Technology, November 14, 1988)
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Abstract:
This thesis is a study in sales tax law, a study on the triple concept of export, import and inters—State sales. It is in seventeen chapters spread in five parts. The introductory is an overview. It presents the thematic thrust of what follows. Part two deals with incidence of sales tax on export and import and the scope of exemption. Part three focuses attention on the various dimensions of the problem of inter—State sale. Part four is an inquiry into parliamentary control on taxes over sales and purchases and highlights inter—State and intra-State implications of discriminatory tax. Part five contains the results of empirical study and the general conclusions of the thesis. In the past no attempt has been made to analyse on identical lines the problems dealt with in this thesis
Description:
Department of Law, Cochin University of Science and
Technology