Santhosh Kumar, G; Deepthi, K V B L; Rama, Krishna Sharma V(er publications, December , 2013)
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Abstract:
While channel coding is a standard method of improving a system’s energy efficiency in digital
communications, its practice does not extend to high-speed links. Increasing demands in network speeds
are placing a large burden on the energy efficiency of high-speed links and render the benefit of channel
coding for these systems a timely subject. The low error rates of interest and the presence of residual
intersymbol interference (ISI) caused by hardware constraints impede the analysis and simulation of coded
high-speed links. Focusing on the residual ISI and combined noise as the dominant error mechanisms, this
paper analyses error correlation through concepts of error region, channel signature, and correlation
distance. This framework provides a deeper insight into joint error behaviours in high-speed links, extends
the range of statistical simulation for coded high-speed links, and provides a case against the use of biased
Monte Carlo methods in this setting
Description:
International Journal of Enhanced Research in Science Technology & Engineering,
Vol. 2 Issue 12, December-2013, pp: (115-124)
Elastic properties of sodium doped Lithium potassium sulphate, LiK0.9Na0.1SO4, crystal has been studied by
ultrasonic Pulse Echo Overlap [PEO] technique and are reported for the first time. The controversy regarding
the type of crystal found while growth is performed at 35 °C with equimolar fraction of Li2SO4H2O, K2SO4
and Na2SO4 has been resolved by studying the elastic properties. The importance of this crystal is that it
exhibits pyroelectric, ferroelectric and electro optic properties. It is simultaneously ferroelastic and
superionic. The elastic properties of LiK0.9Na0.1SO4 crystal are well studied by measuring ultrasonic velocity
in the crystal in certain specified crystallographic directions and evaluating the elastic stiffness constants,
compliance constants and Poisson’s ratios. The anisotropy in the elastic properties of the crystal are well
explained by the pictorial representation of the surface plots of phase velocity, slowness and linear
compressibility in a-b and a-c planes.
The aim of the study was to investigate the relevance of e—learning in continuing education of
library professionals in the universities in Kerala. /55 part of a survey of library professionals in the
seven major Universities in Kerala to find their continuing education needs, it was found that
majority of the library professionals attend continuing education programmes (CEP) to be trained
in the latest technologies. Internet resources were the preferred mode of information source by
38.9 per cent of the library professionals. The importance of continuing education in developing
the competencies of library professionals is also stressed
Description:
E-Resources and E-Learning:Challenges and Opportunities ,University of Calicut
Santhosh Kumar, G(Cochin University of Science And Technology, June 23, 2010)
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Abstract:
Semantic Web: Software agents on the Semantic Web may use commonly agreed service
language, which enables co-ordination between agents and proactive delivery of learning
materials in the context of actual problems. The vision is that each user has his own
personalized agent that communicates with other agents.
Jayaraj, M K(Institute of Materials Engineering Australasia Ltd, 2005)
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Abstract:
ZnGa2O4 spinel is a promising new UV transparent electronic conductor. Enhancing the electrical conductivity of this
potential oxide phosphor can make it a promising transparent conducting oxide. In this paper, we have investigated the
effects of processing and doping on the conductivity of semiconducting ZnGa2O4, particularly thin films. Crystalline
zinc gallate thin films have been deposited on fused quartz substrates employing the pulsed laser deposition (PLD)
technique at room temperature for an oxygen partial pressure of 0.1 Pa (0.001mbar). The films were found to be UV
transparent, the band gap of which shifted to 4.75eV on hydrogen annealing. The band gap of the oxygen stoichiometric
bulk powder samples (4.55eV) determined from diffuse reflection spectrum (DRS) shifted to 4.81eV on reduction in a
hydrogen atmosphere. The electrical conductivity improved when Sn was incorporated into the ZnGa2O4 spinel. The
conductivity of ZnGa2O4:Sn thin films was further improved on reduction.
Heterojunction diodes of n-type ZnO/p-type silicon (100) were fabricated by
12 pulsed laser deposition of ZnO films on p-Si substrates in oxygen ambient at
13 different pressures. These heterojunctions were found to be rectifying with a
14 maximum forward-to-reverse current ratio of about 1,000 in the applied
15 voltage range of -5 V to +5 V. The turn-on voltage of the heterojunctions was
16 found to depend on the ambient oxygen pressure during the growth of the ZnO
17 film. The current density–voltage characteristics and the variation of the
18 series resistance of the n-ZnO/p-Si heterojunctions were found to be in line
19 with the Anderson model and Burstein-Moss (BM) shift.
Syamaprasad, U; Vallabhan, C P G(Elsevier, May , 1981)
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Abstract:
Anomalous variations of d.c. electrical conductivity with temperature are observed in ammonium sulphate single crystals, suggesting a possible phase transition at 150°C. Measurements of thermally stimulated current also support these results. The mechanism of electrical conduction is explained on the basis of studies made on doped and quenched crystals.
Navil Kumar, R; Vallabhan, C P G(IOP Publishing, 1989)
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Abstract:
DC and AC electrical conductivity measurements in single crystals of diammonium hydrogen phosphate along the c axis show anomalous variations at 174, 246 and 416 K. The low-frequency dielectric constant also exhibits peaks exactly at these temperatures with a thermal hysteresis of 13 degrees C for the peak at 416 K. These specific features of the electrical properties are in agreement with earlier NMR second-moment data and can be identified with three distinct phase transitions that occur in the crystal. The electrical conductivity values have been found to increase linearly with impurity concentration in specimens doped with a specific amount of SO42- ions. The mechanisms of the phase transition and of the electrical conduction process are discussed in detail.
Santhakumari, N C; Vallabhan, C P G(Elsevier, May , 1992)
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Abstract:
D.C. and a.c. electrical conductivities, dielectric constant and dielectric loss factor in single crystals of ethylenediammonium sulphate, (H3NCH2CH2NH3)(SO4), have been measured axiswise as a function of temperature. Anomalous variations in all the above properties at 480 K indicate the occurrence of a phase transition in the above material at this temperature. The existence of such a phase transition is also confirmed by DSC measurements. Electrical conductivity results are analysed and the activation energies of conduction at different temperature regions have been evaluated from the logσ vs 103T−1 plot. Possible mechanisms for the electrical conduction process are discussed, the available results being in favour of a proton transport model.
Santhakumari, N C; Vallabhan, C P G(Elsevier, April , 1991)
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Abstract:
dc and ac electrical conductivities, dielectric constant and dielectric loss factor in single crystals of ethylenediammonium dinitrate (EDN) have been measured axiswise as a function of temperature. All the above properties exhibit anomalous variations at 404 K thereby confirming the occurence of a phase transition in EDN at this temperature. Electrical conductivity parameters have been evaluated and possible conduction mechanisms are discussed. The role of protons in electrical trasport phenomenon is established by chemical analysis.
Dipyrromethene-Cu(II) derivatives possessing two dodecane alkyl chains have been used for the modification of gold
electrodes. Electroactive host molecules have been incorporated into a lipophilic dodecanethiol SAM deposited onto
gold electrodes through hydrophobic and van der Waals interactions (embedment technique). The presence of
dipyrromethene-Cu(II) redox centers on the electrode surface was proved by cyclic voltammetry and Osteryoung
square-wave voltammetry. The Au electrodes incorporating redox active Cu(II)-dipyrromethene SAMs were used for
the direct voltammetric determination of paracetamol in human plasma.
Girish Kumar,K; Joseph, Renjini(Taylor & Francis, June 1, 2009)
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Abstract:
A metalloporphyrin incorporated carbon paste sensor has been developed
for the determination of metronidazole benzoate (MTZB). Zn(II) complex
of 5,10,15,20-tetrakis (3-methoxy-4-hydroxy phenyl) porphyrin (TMHPP) was
used as the active material. The MTZB gave a well-defined reduction peak at
- 0.713V in 0.1 mol l -1 phosphate buffer solution of pH around 7. Compared
with bare carbon paste electrode (CPE), the TMHPP Zn(II) modified electrode
significantly enhanced the reduction peak current of MTZB as well as lowered
its reduction potential. Under optimum conditions the reduction peak current
was proportional to MTZB concentration over the range 1×10-3 mol1-1 to 1×10-5mol1-1. The detection limit was found to be 4.36×10-6mol1-1
. This
sensor has been successfully applied for the determination of MTZB in pharmaceutical
formulations and urine samples.
Girish Kumar,K; Thomas, D; Joseph, R; Issac, S; Lonappan, L(The Institution of Engineering and Technology, October 10, 2011)
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Abstract:
A differential pulse voltammetric sensor for the determination of tamsulosin hydrochloride (TAM) using multiwalled carbon nanotubes
(MWNTs)–Nafion-modified glassy carbon electrode (GCE) has been developed. MWNTs were dispersed in water with the help of Nafion
and were used to modify the surface of GCE via solvent evaporation. At MWNT-modified electrode, TAM gave a well-defined oxidation
peak at a potential of 1084 mV in 0.1 M acetate buffer solution of pH 5. Compared to the bare electrode, the peak current of TAM
showed a marked increase and the peak potential showed a negative deviation. The determination conditions, such as the amount of
MWNT–Nafion suspension, pH of the supporting electrolyte and scan rate, were optimised. Under optimum conditions, the oxidation
peak current was proportional to the concentration of TAM in the range 1 × 1023 M–3 × 1027 M with a detection limit of
9.8 × 1028 M. The developed sensor showed good stability, selectivity and was successfully used for the determination of TAM in pharmaceutical
formulations and urine samples
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.