• 한국정보통신학회논문지
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• 제15권10호
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• pp.2257-2264
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• 2011

무선 센서 네트워크에서 센서 노드들은 제한된 자원을 가지며, 에너지의 대부분을 통신에 소비한다. 대부분의 트래픽이 싱크 노드를 향해 전달되는 형태를 지니므로, 순간적인 네트워크 혼잡 발생 가능성이 높다. 네트워크 혼잡은 패킷의 폐기를 초래하고, 폐기된 패킷의 재전송으로 인하여 에너지가 낭비된다. 특히 싱크 노드로부터 멀리 위치한 센서 노드에서 생성된 패킷의 손실은 추가적인 에너지 소비를 나타낸다. 본 논문에서는 패킷의 우선순위와 혼잡 레벨 뿐만 아니라 홉 카운트를 고려하여 패킷 전송여부를 결정하는 트래픽 제어 메커니즘을 제안한다. 시뮬레이션 방법에 의한 성능 분석을 통해 제안된 메커니즘이 에너지 효율성을 개선한 하였다.

• Journal of Photoscience
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• 제12권1호
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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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• 제11권3호
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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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• 제41권7호
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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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• 제38권9호
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• pp.1032-1038
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• 2014

본 연구에서는 병렬 마이크로 채널에서 FC-72의 비등 열전달 특성을 파악하기 위한 실험적 연구를 수행하였다. 병렬 마이크로 채널은 깊이 0.2 mm, 폭 0.45 mm, 길이 60 mm의 15개의 마이크로 채널로 구성되었으며, 실험은 열유속 $16.4kW/m^2$와 $25.6kW/m^2$의 조건에서 수행되었으며, 이때 질량유속 300, 400 그리고 $500kg/m^2s$의 범위에서 이루어졌다. 실험을 통해 측정된 열전달 계수는 낮은 건도에서는 건도가 증가함에 따라 급격하게 감소하며, 일정 건도 이상에서는 일정하게 유지되었다. 본 연구를 통해 마이크로 채널에서 FC-72의 비등 열전달 메커니즘을 확인하였으며, 실험에서 얻어진 열전달 계수는 열전달 계수를 예측하기 위한 기존의 상관식들과 비교 분석하였다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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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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• 제32권2호
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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.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제36회 동계학술대회 초록집
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• pp.223.2-223.2
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• 2009

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제36회 동계학술대회 초록집
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• pp.64.1-64.1
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• 2009

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2805-2808
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• 2011