• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.639-645
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• 2016

We herein report efficient triplet-triplet annihilation upconversion (TTA-UC) achieved in various non-toxic and non-volatile vegetable oils as a UC media using platinum-octaethylporphyrin (PtOEP) and 9,10-diphenylanthracene (DPA) as a sensitizer and acceptor, respectively. Green-to-blue UC was readily achieved from PtOEP/DPA solution in vegetable oils with the quantum yield of 8% without any deoxygenation process. The UC efficiency was found to be significantly dependent on the contents of unsaturated hydrocarbon in vegetable oils and viscosity of the solution, as well. Though the Stern-volmer constant and quantum yield in vegetable oils were measured to be lower than those measured in the deaerated organic solvent, the quenching efficiency was still high enough to be 93%. In the sunflower oil, the UC threshold intensity ($I_{th}$) was approx. $100mW/cm^2$, which is far larger than the sunlight intensity, but we believe that the UC achieved in non-toxic and air-saturated media was still highly applicable to nontraditional visualization techniques such as bioimaging.

• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.516-521
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• 2008

This study was conducted to optimize the analysis condition and quantify the 2-acetyl-1-pyrroline (2AP) in the brown aroma rice. Extraction effect of the solvent for 2AP was the order of ethanol>acetonitrile>methanol in the range from 30 to $90^{\circ}C$. In the extraction time of 15, 30, 60, and 90 min, the 30 min had the highest 2AP concentration, and it was decreased according to lapse of time. At grinding time, 5 sec resulted in highest 2AP concentration. It was recommended that five sec grinding time, using ethanol, at $90^{\circ}C$ for 30 min was the optimization conditions to quantify the 2AP. Hyangmibyeo2ho and Aranghyangchalbyeo were mild aroma. In the foreign aroma rice, 11 of 19 accessions of Indica types and 2 of 6 accessions of Japonica types were more than mild aroma. Finally, 30 accessions of aroma rice were selected based on their 2AP concentration and agronomic traits.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.1-5
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• 2018

The present study investigated the characteristics of vertical sagging down of high temperature in chamber and characteristics of vertical sagging down in the outdoor asphalt sheet and asphalt seal under korea ltimate condition using asphalt seal products of solvent based type, solventless type, water dispersion type, and heat melting type, which are currently applied in Korea. Prior to the investigation of outdoor vertical sagging down characteristics, the assessment of sagging down performance of single use of sealing products at $20^{\circ}C$, $40^{\circ}C$, $60^{\circ}C$ was conducted and the result showed that sagging down did not occur at $20^{\circ}C$ but some solventless type, water dispersion type specimens at $40^{\circ}C$ had sagging down up to 10 mm. In addition, some solventless type, water dispersion type specimens had sagging down up to 55 mm at $60^{\circ}C$. For specimens to which asphalt seal and renovated asphalt sheet were layered over the outdoor concrete vertical surface, sheet sagging and sagging down occurred up to 50 mm in water dispersion specimens after three month later since the construction in summer.

• Korean journal of food and cookery science
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• v.16 no.3
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• pp.221-225
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• 2000

This study was conducted to investigate the usefulness of Perilla frutescens var. acuta as a natural spice. Volatile flavor components of dried Perilla frutescens var. acuta were extracted by supercritical fluid extraction method using diethyl ether as solvent. Essential oils were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS). Identification of volatile flavor components was based on the RI of GC and mass spectrum of GC-MS. A total of 24 components, including 4 hydrocarbons, 3 aldehydes, 8 alcohols, 4 esters, 3 acids and 2 miscellaneous components were identified in the essential oils. L-Perillaldehyde was found to be the major volatile flavor component of dried Perilla frutescens var. acuta. The masking effects of Perilla frutescens var. acuta on meaty and fishy flavor were measured by sensory evaluation. Meaty flavor was significantly reduced with the addition of 0.05%, 0.1%, and 0.2% Perilla frutescens var. acuta. The addition of 0.1% and 0.2% powdered Perilla frutescens var. acuta also reduced the fishy flavor of mackerel.

• Korean journal of food and cookery science
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• v.16 no.3
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• pp.216-220
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• 2000

Volatile flavor components in the fruits of dried Zanthoxylum schinifolium were extracted by supercritical fluid extraction method using diethyl ether as solvent. Essential oils were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS). Identification of volatile flavor components was based on the RI of GC and mass spectrum of GC-MS. A total of 30 components, including 6 hydrocarbons, 4 aldehydes, 8 alcohols, 5 esters, 4 acids and 3 miscellaneous components were identified in the essential oils. Geranyl acetate, ${\beta}$-phellandrene, D-limonene and citronellal were found to be major volatile flavor components in fruits of dried Zanthoxylum schinifolium. The masking effects of Zanthoxylum schinifolium on meaty and fishy flavor were measured by sensory evaluation to investigate the usefulness of Zanthoxylum schinifolium as a natural spice. Meaty flavor was significantly reduced with the addition of 0.05% and 0.1% Zanthoxylum schinifolium. And the addition of 0.l% powdered Zanthoxylum schinifolium also reduced the fishy flavor of mackerel.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.68-73
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• 1995

Extraction yields of Hizikia fusiforme and Aloe vera Linne by supercritical carbon dioxide($SC-CO_{2}$) with and without ethanol as a cosolvent, and antimicrobial activities of the extracts against Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Alternaria sp. were determined. Both yield and solubility of the extracts from Hizikia fusiforme and Aloe vera Linne by $SC-CO_{2}$ with ethanol were two times greater than those by only $SC-CO_{2}$. All of the extracts demonstrated antimicrobial activities in the decreasing order of bacteria, yeast and fungus. The extracts by $SC-CO_{2}$ with ethanol showed almost the same degree of microbial growth inhibition as those by only $SC-CO_{2}$. Based upon these data, it was speculated that the components soluble in nonpolar solvent might be more responsible for the antimicrobial activity.

• KSBB Journal
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• v.20 no.3
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• pp.238-243
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• 2005

Succinic acid has recently been drawing much interest as a raw material for biodegradable polymer. In this study acetic acid was removed by reactive extraction with various amines dissolved in various diluents. Distribution coefficients were determined as the kind of amines, diluents, and pHs of continuous phase. The extraction capacity increased with the polarity of diluent and the decrease of pH from the artificial binary solution. Based on the different extractability for succinic acid and acetic acid from the artificial binary solution, the removal of acetic acid from fermentation broth was investigated using various amines and diluents. In addition, the extractability and selectivity of CLA for succinic acid and acetic acid from fermentation broth were higher than that of straight solvent extraction.

• Polymer(Korea)
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• v.30 no.2
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• pp.140-145
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• 2006

The mort commonly available substrate material is glass in the display fibrication process. However, glass is not desirable due to its heaviness and fragility. Recently, plastics such polysulfone (PSF), polyethesulfone (PES), polycarbonate (PC), polyethylene terephthalate (PET) and cyclic olefin polymers (COP) have been investigated to replace glass as a substrate material for display fibrication. Plastic substrates are advantageous in that they are lightweight, huh impart resistance, flexibility, and ability for roll to roll manufacturing process. But many plastics have poor chemical resistance in organic solvent. The chemica resistance is also lequired because they are exposed to solvents for various chemical treatments din the manufacturing process. So, we have an interest in the chemical modification of PSF to improve chemical resistance. We introduced crosslinkable imide moieties using chloromethylation method for the modification of PSF which could be overcome above shortcomings for display substrate based on plastic film. We prepared the cross-linked polysulfone films which were represented chemical resistance in HeOH, THF, DMSO and NMP. The thermal properties were measured by TGA, DSC and TMA. As the results, we have confirmed to enhance of the thermal property. They had low coefficient of thermal expansion (CTE) which decreased to 15% and had increased $T_g\;from\;180^{\circ}C\;to\;252^{\circ}C$. Cross-linked polysulfone films with imide side-chain had good optical properties and chemical resistance so that they could be used as flexible display substrate.

• Clean Technology
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• v.17 no.4
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• pp.285-299
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• 2011

As one of the REACH obligations, the extended safety data sheet (eSDS) should be communicated within the supply chain under the REACH Regulation. Based on technical guidance documents published on the ECHAs website and survey of EU's recent REACH-related informations, this paper includes a study on details of how to develop exposure scenarios (ES) such as structure of ES, process of ES develpoment, standard workflows and key input data to develop ES with an introduction of eSDS concept. This paper also contains an overview on operational conditions (OCs) and risk management measures (RMMs) that are what to consider when building an ES. The structure of Chesar (Chemical Safety Assessment and Report tool) developed by European Chemicals Agency (ECHA) is studied with a review of the available exposure estimation tools for workers, environment and consumers. Case example of generic exposure scenario (GES) for organic solvent is presented. To guide Korean EU-exporting companies, their participating roles in three steps of preparing ES are addressed.

• Clean Technology
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• v.26 no.2
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• pp.91-95
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• 2020

A new eco-friendly synthetic method for N-hydroxysuccinimide (NHS), widely used in the pharmaceutical and fine chemical industries, is developed. Conventional synthesis method yields NHS of about 70% after its reaction with NH₂OH to succinic acid. In this method, NHS can be obtained using low-cost succinic acid, but a great deal of solvents are required as an extraction method to purify NHS, while the work-up process is complicated, resulting in low yield. In addition, there is a safety risk due to the high reaction temperature for commercial production, and it is not economical due to the high cost of production from the generation of much waste because of an acid catalyst and the use of various solvents. In order to make up for this shortcoming, this study used succinic anhydride as a raw material under low temperature reaction and developed a new eco-friendly industrial synthesis method using isobutyl alcohol for a single solvent and non-catalytic reaction. The economic evaluation confirms that there is a cost reduction effect of about 20%. In the future, based on this result, studies may establish a commercial production technology through scale-up research and proceed with foreign technology transfer.