• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2257-2264
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• 2011

Sensor nodes in Wireless sensor network have limited resources and consume almost all energy to the communication. For its traffic feature as a burst traffic type toward a sink node, it has high probability to network congestion. Network congestion causes packet drops and retransmission of dropped packets draws energy consumption. In particular, the loss of packet that is from the sensor node far away from a sink node requires additional energy consumption by frequent retransmission. This paper presents a traffic control mechanism that determines packet transfer by considering priority of packet and congestion level as well as hop count. Analysis of proposed mechanism by simulation demonstrated that it improved energy efficiency.

• Journal of Photoscience
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• v.12 no.1
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• pp.11-15
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• 2005

The mechanism of interaction of two drugs viz., amoxicillin and cloxacillin with bovine serum albumin has been investigated using fluorescence absorption and circular dichroism spectroscopy. The quenching mechanism of fluorescence of bovine serum albumin by amoxicillin and cloxacillin was discussed. The binding sites number n and apparent binding constant Kwere measured by fluorescence quenching method. The thermodynamic parameters obtained from data at different temperatures were calculated. The distance r between donor (bovine serum albumin) and acceptor (amoxicillin and cloxacillin) was obtained according to Forster theory of non-radiative energy transfer. The effect of common ions on binding constant was also investigated. The results of synchronous fluorescence spectra, UV-vis absorption spectra and circular dichroism of BSA in presence of amoxicillin and cloxacillin show that the conformation of bovine serum albumin changed

• Bulletin of the Korean Chemical Society
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• v.11 no.3
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• pp.224-227
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• 1990

The excitation mechanism of polycyclic aromatic amines (amino-PAHs) and polycyclic aromatic hydrocarbons(PAHs) for the chemiluminescence arising from the reaction between oxalate ester, bis(2,4,6-trichlorophenyl)oxalate (TCPO) or bis(2,4-dinitrophenyl)oxalate (DNPO) and hydrogen peroxide has been studied in terms of the excitation efficiencies to singlet excitation energies and the oxidative half-wave potentials. As a results of the study, the excitations of both amino-PAHs and PAHs appear to involve the charge transfer type of energy transfer. However the chemiluminescence efficiency corrected for fluorescence quantum yield of the amino-PAHs are varied more sensitively to the oxidative half-wave potential than that of PAHs possibly due to the large difference in solvation energy between the compounds and their ions.

• Nuclear Engineering and Technology
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• v.41 no.7
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• pp.907-920
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• 2009

This study was performed to evaluate the prediction capability of a commercial CFD code and to investigate the effects of different geometries such as a 4.4 mm tube and an 8/10 mm annular channel on the detailed flow structures. A numerical simulation was performed for the conditions, at which the experimental data was produced by the test facility SPHINX. A 2-dimensional axisymmetric steady flow was assumed for computational simplicity. The RNG $\kappa-\varepsilon$ turbulence model (RNG) with an enhanced wall treatment option, SST $\kappa-\omega$ (SST) and low Reynolds Abid turbulence model (ABD) were employed and the numerical predictions were compared with the experimental data generated from the experiment. The effects of the geometry on heat transfer were investigated. The flow and temperature fields were also examined in order to investigate the mechanism of heat transfer near the wall. The local heat transfer coefficient predicted by the RNG model is very close to the measurement result for the tube. In contrast, the local heat transfer coefficient predicted by the SST and ABD models is closer to the measurement for the annular channel.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1032-1038
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• 2014

In this study, an experimental study was performed to understand the boiling heat transfer characteristics of FC-72 in parallel micro-channels. The parallel micro-channels contained channels having a $0.2mm{\times}0.45mm$ [$H{\times}W$] cross section and length of 60 mm. And heat flux was varied from 16.4 to $25.6kW/m^2$ and mass fluxes from 300 to $500kg/m^2s$. The measured heat transfer coefficient was sharply decreased at lower vapor quality and then it was kept approximately constant as the vapor quality is increased. From the experimental results, the boiling heat transfer mechanism of FC-72 was confirmed and the measured heat transfer coefficient was compared and analyzed with the existing correlations to predict the heat transfer coefficient.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.232-232
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• 2006

Intramolecular energy transfer in heteroleptic red phosphorescent dopant materials with mixed ligand units in one molecule was studied. 1-phenylisoquinoline(piq) and phenylpyridine(ppy) moieties were introduced as ligands for Ir based phosphorescent dopants and light emission mechanism was investigated. Intramolecular energy transfer from ppy ligand to piq ligand resulted in pure red emission without any green emission from ppy. Current efficiency of red devices was improved from 4 cd/A to 4.8 cd/A by using mixed ligand structures and deposition temperature of red dopant could be lowered by introducing ppy ligand.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.439-443
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• 2011

Using the projection operator technique, a reduced density matrix theory for linear absorption spectrum of energy transfer systems is developed for the theoretical absorption line shape of the systems with non-Condon transitions. As an application, we considered a model system of OH vibrations of water. In the present model calculation, the OH vibration modes are coupled to each other via intra-molecular coupling mechanism while their intermolecular couplings are turned off. The time-correlation functions appearing in the formulation are calculated from a mixed quantum/classical mechanics method. The present theory is successful in reproducing the exact absorption line shape. Also the present theory was improved from an existing approximate theory, time-averaged approximation approach.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.223.2-223.2
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• 2009

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.64.1-64.1
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• 2009

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2805-2808
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• 2011