Harikumar,P S; Dr.Sivasankara Pillai, V N(Cochin University of Science and Technology, 1990)
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Abstract:
The primary aim of these investigations was to probe the elecnuchemical
and material science aspects of some selected metal phthalocyanines(MPcs).Metal phthalocyanines are characterised by a unique planar molecular structure. As a single
class of compounds they have been the subject of ever increasing number of physicochemical and
technological investigations. During the last two decades the literature on these compounds was
flooded by an outpour of original publications and patents. Almost every branch of materials science
has benefited by their application-swface coating, printing, electrophotography, photoelectrochemistry,
electronics and medicine to name a few.The present study was confined to the electrical and electrochemical properties of cobalt,
nickel, zinc. iron and copper phthalocyanines. The use of soluble Pes as corrosion inhibitor for
aluminium was also investigated.In the introductory section of the thesis, the work done so far on MPcs is reviewed. In this
review emphasis is given to their general methods of synthesis and the physicochemical properties.In phthalocyanine chemistry one of the formidable tasks is the isolation of singular species.
In the second chapter the methods of synthesis and purification are presented with necessary
experimental details.The studies on plasma modified films of CoPe, FePc, ZnPc. NiPc and CuPc are also presented.Modification of electron transfer process by such films for reversible redox systems
is taken as the criterion to establish enhanced electrocatalytic activity.Metal phthalocyanines are p- type semiconductors and the conductivity is enhanced by
doping with iodine. The effect of doping on the activation energy of the conduction process is
evaluated by measuring the temperature dependent variation of conductivity. Effect of thennal
treatment on iodine doped CoPc is investigated by DSC,magnetic susceptibility, IR, ESR and
electronic spectra. The elecnucatalytic activity of such doped materials was probed by cyclic
voltammetry.The electron transfer mediation characteristics of MPc films depend on the film thickness.
The influence of reducing the effective thickness of the MPc film by dispersing it into a conductive
polymeric matrix was investigated. Tetrasulphonated cobalt phthalocyanine (CoTSP) was
electrostatically immobilised into polyaniline and poly(o-toluidine) under varied conditions.The studies on corrosion inhibition of aluminium by CoTSP and CuTSP and By virtue of their anionic character they are soluble in water and are strongly adsorbed on aluminium.
Hence they can act as corrosion inhibitors. CoTSP is also known to catalyze the reduction of
dioxygen.This reaction can accelerate the anodic dissolution of metal as a complementary reaction.
The influence of these conflicting properties of CoTSP on the corrosion of aluminium was studied
and compared with those of CuTSP.In the course of these investigations a number of gadgets like cell for measuring the electrical
conductivity of solids under non-isothermal conditions, low power rf oscillator and a rotating disc
electrode were fabricated.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Sarin, V P; Nishamol, M S; Gijo,Augustin; Mohanan, P; Aanandan,C K; Vasudevan, K(John Wiley & Sons, July , 2008)
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Abstract:
A new design of a dual-band dual-polarized electromagnetically coupled slot loaded square patch antenna, covering the WLAN 5.2 GHz and 5.8 GHz bands, achieving bandwidth enhancement by using tapered slot structure, is presented here. The proposed antenna covers 5.09–5.47 GHz and 5.7–5.88 GHz bands. Details of the antenna design along with experimental and simulated results are presented and discussed.
In this paper, a dual port, dual frequency, dual polarized,
octagonal shaped Microstrip patch antenna, suitable for GPS
applications is discussed experimentally and theoretically. The
proposed antenna configuration is characterized by good
impedance bandwidth, gain, isolation between two ports and
broad radiation patterns
Description:
Personal Wireless Communications, 2005. ICPWC 2005. 2005 IEEE International Conference on,PP 305-307
Harilal, S S; Bindhu, C V; Issac, Riju C; Nampoori, V P N; Vallabhan, C P G(American Institute of Physics, September 1, 1997)
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Abstract:
Plasma generated by fundamental radiation from a Nd:YAG laser focused onto a graphite target is studied spectroscopically. Measured line profiles of several ionic species were used to infer electron temperature and density at several sections located in front of the target surface. Line intensities of successive ionization states of carbon were used for electron temperature calculations. Stark broadened profiles of singly ionized species have been utilized for electron density measurements. Electron density as well as electron temperature were studied as functions of laser irradiance and time elapsed after the incidence of laser pulse. The validity of the assumption of local thermodynamic equilibrium is discussed in light of the results obtained.
Geetha K, Varier; Harilal, S S; Bindhu, C V; Riju, C Issac; Nampoori, V P N; Vallabhan, C P G(December 3, 2011)
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Abstract:
Irradiation of a Polymethyl methacrylate target using a pulsed Nd-YAG laser causes plasma formation in the vicinity of the target. The refractive index gradient due to the presence of the plasma is probed using phase-shift detection technique. The phase-shift technique is a simple but sensitive technique for the determination of laser ablation threshold of solids. The number density of laser generated plasma above the ablation threshold from Polymethyl methacrylate is calculated as a function of laser fluence. The number density varies from 2×1016 cm-3 to 2×1017 cm-3 in the fluence interval 2.8-13 J · cm-2.
The electron-donor properties of Sm2O3 activated at 300, 500, and 800°C are reported from studies on the adsorption of electron acceptors of various electron affinities (electron affinity values in eV are given in parentheses): 7,7,8,8-tetracyanoquino-dimethane (2.84), 2,3,5,6-tetrachloro-1,4-benzoquinone (2.40), p-dinitrobenzene (1.77), and m-dinitrobenzene (1.26) in acetonitrile and 1,4-dioxane. The extent of electron transfer during the adsorption was determined from magnetic measurements. The acid-base properties of Sm2O3 at different activation temperatures are reported using a set of Hammett indicators. Electron donor-acceptor interactions at interfaces are important in elucidating the adhesion forces.
Sugunan, S; Jalaja, J M(Indian Journal of Chemistry, March , 1995)
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Abstract:
The electron donating properties of Ce02 and its mixed
oxides with alumina have been determined from the studies
of adsorption of electron acceptors of various electron
affinities on the surface of these oxides. The catalytic
activity of these oxides towards some reactions such as
oxidation of alcohols and reduction of ketones have been
Correlated with their surface electrondonor properties. The
surface acidity/basicity of these oxides have also been
determined by titration method using a set of Hammett
indicators.
The catalytic activity of Perovskite-type mixed oxides (LaCo03 . PrCo03 and SmCo03 ) for the
reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-Ponndorf-Verley reduction)
has been studied. The data have been correlated with the surface electron donor properties
of these mixed oxides.
Sugunan, S; Devika Rani, G(Indian Journal of Chemistry, November , 1993)
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Abstract:
The adsorption of electron acceptors, viz.,7,7,8,8-tetracyanoquinodimethane(TCNQ), 2,3,5,6-tetrachloro-p-
benzoquinone (chloranil) and p-dinitrobenzene
(PDNB) on the surface of three rare earth oxides Y2O3,
Nd203 and Pr6O11 has been studied in acetonitrile and
dioxan. From the radical concentration on the surface
determined using ESR spectral data, the electron donor
strength of the rare earth oxides are reported.
Suresh, Vettoor V; Nandakumaran, V M(World Scientific Publishing Company, 1990)
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Abstract:
Electron-phonon interaction is considered within the framework of the fluctuating
valence of Cu atoms. Anderson's lattice Hamiltonian is suitably modified to take this into
account. Using Green's function technique tbe possible quasiparticle excitations' are
determined. The quantity 2delta k(O)/ kB Tc is calculated for Tc= 40 K. The calculated values
are in good agreement with the experimental results.
Jayan,Thomas; Sivasankara Pillai,V N(Department of Applied Chemistry,Faculty of Science, 1995)
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Abstract:
The thesis deals with the preparation of chemical, optical, thermal and electrical characterization of five compounds, namely metal free naphthalocyanine, vanadyl napthalocyanine, zinc naphlocyanine, europium dinaphthalocyanine, and europium diphthalocyanine in the pristine and iodine-doped forms. Two important technological properties of these compounds have been investigated. The electrical properties are important in applications sensors and semiconductor lasers. Opto-thermal properties assume significance for optical imaging and data recording. The electrical properties were investigated by dc and ac techniques. This work has revealed some novel information on the conduction mechanism in five macrocyclic compounds and their iodine-doped forms. Also useful data on the thermal diffusivity of the target compounds have been obtained by optical techniques.
Narayanan, P; Dr.Sivasankara Pillai, V N(Cochin University of Science and Technology, September , 1992)
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Abstract:
Metal phthalocyanines have some unique optical
properties which are exploited for dyeing fibers and films
used in applicationslike dye lasing and optical information
storage. Aggregation of dye molecules modifies their
absorption and emission spectra with concomitant
degradation in their energy transfer characteristics. MPcs
as such have poor processability and are seldom used in
solid matrices. The finest energy transfer characteristics
are shown by the monomers of metal phthalocyanines. In the
third chapter of this thesis the studies on two series of
metal phthalocyanines are repoted
Description:
Department of Applied Chemistry, Cochin University of Science And Technology
Victor Anandkumar, S; Dr.Francis,C A(Cochin University of Science and Technology., November , 2007)
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Abstract:
Information and Communication Technologies (ICTs) have a dramatic
impact on the tourism industry because they force this sector as a whole to
rethink the way in which it organises its business . In
the light of such rethinking within the tourism industry, this study has
focussed on the Small and Medium Tourism Enterprises (SMTEs) in two
island destinations, namely Mauritius and Andaman Islands, India.Suggestions. The findings
conceming SMTEs in Mauritius and Andaman Islands have been compared
to make some destination-specific inferences. The relevance of the findings
has been discussed with reference to the SMTEs in the two destinations as
well as the possible acceptability in other comparable settings. Suggestions
have been made for further research in SMTEs’ use of the Internet for
marketing function.
Description:
School of Management Studies, Cochin
University of Science and Technology.
Harilal, S S; Issac, Riju C; Bindhu, C V; Nampoori, V P N; Vallabhan, C P G(American Institute of Physics, April , 1997)
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Abstract:
The emission features of laser ablated graphite plume generated in a helium ambient atmosphere have been investigated with time and space resolved plasma diagnostic technique. Time resolved optical emission spectroscopy is employed to reveal the velocity distribution of different species ejected during ablation. At lower values of laser fluences only a slowly propagating component of C2 is seen. At high fluences emission from C2 shows a twin peak distribution in time. The formation of an emission peak with diminished time delay giving an energetic peak at higher laser fluences is attributed to many body recombination. It is also observed that these double peaks get modified into triple peak time of flight distribution at distances greater than 16 mm from the target. The occurrence of multiple peaks in the C2 emission is mainly due to the delays caused from the different formation mechanism of C2 species. The velocity distribution of the faster peak exhibits an oscillating character with distance from the target surface.