• Conservation Science in Museum
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• v.27
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• pp.67-90
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• 2022

A C-46 transport aircraft, which can be thought of as a large cultural heritage item from the modern period, was subjected to paint analysis and conservation treatment in preparation for its exhibition. The C-46 is the first aircraft ever dispatched to overseas combat zones by the Korean Air Force and carried out missions during the Vietnam War. The aircraft is mainly made of aluminum and shows signs of corrosion on its surface, including pitting and etching, as well as gray and white powdery attachments. In the analysis of the paint, diatomite(SiO₂·nH₂O) was confirmed in the red paint, titanium dioxide(TiO₂) was identified in the white paint, black iron oxide(Fe₃O₄) was detected in the black paint, and colcothar(Fe₃O₄) mixed with putty was confirmed in the blue paint. Infrared spectroscopy revealed the use of alkyd resin in the paint on the main body and nitrocellulose in the Taegeuk pattern. During the conservation treatment, mechanical cleaning, such as sanding, was conducted to remove paint and varnish from the surface. Corrosion was removed by sanding and cleaning with chemical solvents, and new paints and varnishes were applied. Through the paint analysis and conservation treatment, the aircraft was made available for exhibition in a stable condition.

• Clean Technology
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• v.29 no.2
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• pp.109-117
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• 2023

The purpose of this study is to develop a method for separating antioxidants and sugars from grape skin extract. The extract was first mixed with a variety of organic solvents to investigate whether the separation was feasible. When employing acetone, ethanol, dimethylsulfoxide, or dimethylformamide, the organic solvent-extract combination formed a single phase. However, when benzene, ethyl acetate, or n-hexane was added to the extract, the mixture separated into an organic and an aqueous phase and the pigments remained in the aqueous phase. On the other hand, when polyethylene glycol-2,000 (PEG-2000) and sodium citrate were added to the extract, the mixture was separated into three layers, with the majority of the flavonoids migrating to the top layer and 53% of the extract's glucose migrating to the bottom layer. The top layer had significant antioxidant activity, whereas the bottom layer showed no antioxidant activity. The glucose recovery in the bottom layer increased as the molecular weight of PEG increased and the highest recovery (67%) was observed when PEG-8,000 was added. The highest flavonoid separation was observed with PEG-2,000, followed by PEG-8,000 and PEG-400. The flavonoid separation when PEG-2,000 was added resulted in a flavonoid recovery of 48% and 0.2% from the top and bottom layers, respectively. Examining the effect of the separated solution using the agar disc diffusion method on yeast cell growth confirmed that the addition of the extract, the top, and the bottom layer did not inhibit cell growth.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1687-1698
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• 2021

This study is to produce multiple layers of liposomes in a supercritical state and encapsulates active ingredients in order to stably encapsulate thermodynamically unstable active ingredients. In order to form a liposome in a supercritical state, a mixed surfactant development including vegetable-derived hydrogenated phosphatidyl choline and their delivative, hydrogenated sucrose distearate was synthesized as high purity. It describes a manufacturing method of injecting liquid carbon dioxide into a reactor to create a supercritical state and stirring to produce a giant liposome, and adding and loading genistein and quercetin. The HLB of the mixed lipid complex (SC-Lipid Complex) was 12.50, and multiple layers of liposome vesicles were formed even at very low concentrations. This surfactant had a specific odor with a pale yellow flake, the specific gravity was 0.972, and the acid value was 0.12, indicating that it was synthesized with high purity. As a result of the emulsifying capacity experiment using 20 wt% capric/capric triglyceride and triethylhexanoin using SC-Lipid Complex, it was found to have 96.2% emulsifying power. SC LIPOSOME GENISTEIN was confirmed that a multi-layer liposome vesicle was formed through a transmission electron microscope (Cryo-TEM) for the supercritical liposome encapsulated with genistein. The primary liposome particle size in which genistein was encapsulated was 253.9 nm, and the secondary capsule size was 18.2 ㎛. Using genistein as the standard substance, the encapsulation efficiency of supercritical liposomes was 99.5%, and general liposomes were found to have an efficiency of 93.6%. In addition, the antioxidant activity experiment in which quercetin was sealed was confirmed by the DPPH method, and it was found that the supercritical liposome significantly maintained excellent antioxidant activity. In this study, thermodynamically unstable raw materials were sealed into liposomes without organic solvents in a supercritical state. Based on these results, it is expected that it can be applied to various forms such as highly functional skincare cosmetics, makeup cosmetics, and scalp protection cosmetics.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.235-246
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• 2018

Paeony has pharmacological activities such as anti-inflammatory, anti-allergic, anti-bacterial, central inhibitory, gastric secretion inhibition, and antispasmodic activities. In addition, its antioxidant activity and whitening effect being reported, thus it is being explored as raw materials for cosmetics. We compared the changes in the contents of paeoniflorin and paeonol in Peony extracts, depending on the changes of extracting solvents, temperature and time. The HPLC method was set up for simultaneous analysis, the system suitabilities were confirmed by using the calibration curves and the QC samples for each assay batch. Paeonol was detected only in roots, and paeoniflorin was higher in leaf and flower than root. Higher concentrations of both ingredients were extracted when the root was used after grinding to a suitable size, and when 30% 1,3-butylene glycol was used as the extraction solvent. Also the concentrations tended to increase at higher temperature and longer time, but the increase was gradual at over $75^{\circ}C$ and 4 hours. The ratio of root, leaf and flower was determined to be 2+2+1g/0.5kg of batch, reaching the contents criteria of paeoniflorin and paeonol. Finally, we selected as the best extraction condition when the raw materials are mixed with 2+2+1g/0.5kg and extracted with 30% 1,3-butylene glycol as an extraction solvent at $75^{\circ}C$ for 4 hours, considering both the concentrations of two components and the cost of raw materials and manufacturing process, The extraction units were scaled up to 10 kg under this condition.

• Journal of Food Hygiene and Safety
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• v.38 no.4
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• pp.211-216
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• 2023

A total of 100 commercially available olive oil products were analyzed for 179 pesticide residues using gas chromatography-tandem mass spectrometry (GC/MS/MS). The olive oil samples were mixed with organic solvents, centrifuged and frozen to remove fat, and pesticide residues were analyzed using the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method. The determination coefficient (R²) of the analysis method used in this study was ≥0.998. The detection limit of the method ranged 0.004-0.006 mg/kg and its quantitative limit ranged 0.012-0.017 mg/kg. The recovery rate (n=5) measured at the level ranging 0.01-0.02, 0.1, and 0.5 mg/kg ranged 66.8-119.5%. The relative standard deviation (RSD) was determined to be ≤5.7%, confirming that this method was suitable for the "Guidelines for Standard Procedures for Preparing Food Test Methods". The results showed that a total of 151 pesticides (including difenoconazole, deltamethrin, oxyfluorfen, kresoxim-methyl, phosmet, pyrimethanil, tebuconazole, and trifloxystrobin) were detected in 64 of the 100 olive oil products. The detection range of these pesticide residues was 0.01-0.30 mg/kg. The percentage acceptable daily intake (%ADI) of the pesticides calculated using ADI and estimated daily intake (EDI) was 0.0001-0.1346, indicating that the detected pesticides were present at safe levels. This study provides basic data for securing the safety of olive oil products by monitoring pesticide residues in commercially available oilve oil products. Collectively, the analysis method used in this study can be used as a method to analyze residual pesticides in edible oils.