• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.762-765
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• 2002

The bilayer organic light-emitting diode using Al (DBM) $_3$ (DBM=Dibenzoylmethane) as an emitting material and poly (N-vinylcarbazole) (PVK) as hole-transport material, emitted bright blue-green light instead of blue light. The blue-green emission is attributed to exciplex formation at the solid interface between Al (DBM) $_3$ and the hole-transport material. The exciplex formation was evidenced by the measurement of the photoluminescence spectra and lifetimes of Al (DBM) $_3$, PVK and an equimolar amount of mixture of Al (DBM) $_3$ and PVK.

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.252-259
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• 2013

A green and simple method to synthesize of 1,4-diketones via aldol reaction of arylglyoxals and ketones such as 1-(4-methoxyphenyl)-2-propanone, deoxybenzoin and substituted acetophenones in the presence of a catalytic amount of DABCO in water at room temperature has been reported. Corresponding 2-hydroxy-1,4-diones were obtained in moderate to high yields with simple separation of obtained solid from reaction mixture and recrystallization.

• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.357-360
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• 2013

Sustainable development is a balance between environment and development. Sustainable development requires sustainable supplies of clean, affordable, and renewable energy sources that do not cause negative impact to the society. This article introduces a green chemistry method to synthesize 2-amino-4H-chromenes that reduces or eliminates the use and generation of hazardous substances in the design, manufacture, and application of chemical products. This method is described using copper (II) sulfate pentahydrate, as a green and reusable catalyst on water. The products were obtained at very good yields, short reaction time, and at lower cost than other reported procedures.

• Journal of the Korean Chemical Society
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• v.63 no.2
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• pp.78-84
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• 2019

High-resolution $^1H$ NMR spectroscopic technique has been widely used as one of the most powerful analytical tools in food chemistry as well as to define molecular structure. The $^1H$ NMR spectra-based metabolomics has focused on classification and chemometric analysis of complex mixtures. The principal component analysis (PCA), an unsupervised clustering method and used to reduce the dimensionality of multivariate data, facilitates direct peak quantitation and pattern recognition. Using a combination of these techniques, the various green teas and black teas brewed were investigated via metabolite profiling. These teas were characterized based on the leaf size and country of cultivation, respectively.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.4129-4132
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• 2011

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3519-3520
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• 2010

• Journal of the Korean Magnetic Resonance Society
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• v.21 no.4
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• pp.119-125
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• 2017

The plucking season of green tea leaves is one of the important parameters that decide their metabolic diversity, quality, and prices. The effects of plucking sghlwleasons on green tea metabolites were investigated through metabolite profiling by $^1H$ NMR spectroscopy. The orthogonal projection on latent structure-discriminant analysis (OPLS-DA) showed clear discriminations of green teas by three different grades depending on plucking seasons: Ujeon, Sejak, and Jungjak. These results suggested that the nine peak groups could be used for diagnostics for identification of high quality Ujeon grade of green tea.

• Journal of the Korean Magnetic Resonance Society
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• v.22 no.4
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• pp.132-138
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• 2018

The plucking season of green tea leaves is one of the important parameters that decide their metabolic quality. Here, we performed the identification and quantity analysis of the metabolites of the green tea using NMR spectroscopy. We assigned the $^1H$ resonances for sixteen metabolites. This analysis found that four metabolites, gallic acid, quinic acid, theobromine and ECG, exhibited clear discrimination of green teas by the three different grades, Ujeon, Sejak and Jungjak. Our results suggest that these four metabolites could be used for diagnostics for quality control of green tea.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1296-1299
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• 2013

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.87-91
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• 2005