• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.87-92
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• 2019

This study is the analysis of causes of printed circuit board (PCB) in collective protection equipment failure and quality improvement. The equipment is a component of the weapon system currently in operation and serves to defend against enemy chemical and biological attack as well as heating and cooling functions. However, during operation in the military, fans of condensate assembly failed to operate. The cause of the failure is the burning of PCB. It was found that the parts were heated according to the continuous cooling operation under the high temperature environmental conditions. Accordingly, the electronic components exposed to high temperature were deteriorated and destroyed. To solve this problem, PCB apply to heatsink. The performance test of improved PCB has been completed. Futhermore system compatibility, positive pressure maintenance and noise test were performed. This improvement confirmed that no faults have occurred in PCB so far. Therefore, the quality of the equipment has improved.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.499-506
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• 2013

As the usuage of tempered glass for touch panel increased rapidly with the development of industry, the amount of UV curable coating solution used to protect glass surfaces during a tempered glass manufacturing process increased as well. The UV curable coating has advantages compared to thermal curing such as shortened curing time and non-solvent. Appropriated polymer and monomer were used as an acid polymer to grant an alkali peeling ability. The monomers were 2-hydroxyl methylacrylate, 1,6-hexanediol diacrylate and dipentaerythritol hexaacrylate which have acryl groups of 1, 2, and 6, respectively. The combination of three different types of photoinhibitors were used and bisphenol A epoxy diacrylate was used as an oligomer. In this study, experiments were carried out by controlling the amount of photoinitiator, oligomer, and additive while maintaining the constant content of the acid polymer and the acrylic monomer. The changes in physical properties according to the additive content were investigated. It was found that the combination of photoinitiators was necessary to achieve the hardness above 4H and it was possible to control the delamination type of the coating film from a sheet to pieces by the addition of TPO as an initiator. The increase in oligomer contents increased the hardness and adhesiveness alongside dissection time. Talc content of 20 wt% showed the best results.

• Journal of Environmental Impact Assessment
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• v.19 no.3
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• pp.259-270
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• 2010

We conducted human risk assessment for exposure to inhalation of chemical substances emitted from the storage tanks of petroleum refineries. To assess human risk, this study calculated chemical emissions from the external floating roofs on storage tank at petroleum refineries, as well as concentrations thereof in the ambient air using the K-SCREEN model, and then determined risk in accordance with the Reference Concentration (RfC) values and Inhalation Unit Risk criteria developed by the US Environmental Protection Agency. The results indicated that non-carcinogenic chemicals have a hazard quotient of less than 1, meaning they have an insignificant effect on human health for residential areas near the storage tanks. Among the known carcinogens, the hazard risk for benzene slightly exceeded $10^{-6}$, indicating the need for corrective reduction measures. The methodology for health impact assessment devised herein provides findings useful in decision making for policy makers and the general public with respect to construction of industrial complexes. However, the methodology proposed herein does have limitations, including discrepancy in results induced by use of U.S. data (due to the lack of usable domestic data). More systematic studies from related researchers will be needed to address these issues and produce more reliable outcomes.

• 보존과학연구
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• s.30
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• pp.125-136
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• 2009

Stone cultural heritages in Korea have a severe damages from chemical and biological weathering because most of them have been situated in outdoors without any suitable protection systems, and this in turn causes deformation and structural damage. To counteract these problems and increase durability, various kinds of conservation materials are used in the conservation and restoration treatments. However until now there are not many practical and technological experiments on this subject. This paper attempts quantitative evaluation of effectiveness about chemical of ethylsilicate based resin for sandstone in Yeongyang-gun. It takes a long time to evaluate durability and side effect after conservation materials treatment. So we use artificial weathering through freezing§ thawing experimental method. As a result of this experiment, porosity and absorptance increased, and elastic wave speed, elastic modules, unconfined compression strength and tensile strength decreased more than before. This study plans to make a scientific method study about weathering factor and mechanism, and to deduce correlation between artificial weathering and natural weathering.

• Research in Plant Disease
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• v.18 no.4
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• pp.331-337
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• 2012

Citrus melanose is one of important disease in citrus cultivation, reducing quality of citrus fruits and resulting in economic loss. Like other diseases in citrus, melanose was mainly protected by chemical fungicide in the field. Recently, alternative method of disease control is highly required due to the side effect of the chemicals. In this study four rhizobacterial strains TRH423-3, MRL408-3, THJ609-3, and TRH415-2 are selected by dual-culture testing its antifungal activity against Diaporthe citri causing citrus melanose. To investigate the protection efficacy of the selected rhizobacterial strains to citrus melanose, the bacteria were pre-treated on citrus leaves following inoculation with melanose pathogen. Pre-treatment with all selected rhizobacterial strains showed disease suppression in which the levels of protection rates were different by the rhizobacterial strains. Additional treatment with the rhizobacterial strains after the pathogen inoculation enhanced protection rates in all cases. The strain MRL408-3 and TRH423-3 were identified as Burkholderia gladioli, TRH415-2 as Pseudomons fluorescens and THJ609-3 as Pseudomonas pudia as a result of analyzing the internal transcript spaces of the rhizobacterial strains rDNA. The selected rhizobacterial strains may be valuable as biological control agents in the environment-friendly citrus farm in which chemical application is limited.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.213-220
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• 2018

BACKGROUND: This study was carried out to determine characteristics of residual pesticides in time-dependent manner and calculate half-lives of the residual pesticides in fresh and dried Chinese matrimony vine. In addition, processing factors were calculated based on the residual concentrations in them. METHODS AND RESULTS: The test pesticides, etofenprox and fenitrothion, were sprayed onto the Chinese matrimony vine plants at once or twice (at seven-day interval) and then samples were collected at 0 (after 3 hours), 1, 3, 5 and 7 days after the last spraying. Dried samples were prepared in hot-air drying oven at $60^{\circ}C$ for 48 hours until water content of less than 20%. Residual concentrations of etofenprox in fresh and dried samples decreased by 54.0-60.9% after 7 days of the last pesticide-application. In case of fenitrothion, the concentrations were found to have decreased by 69.2-76.5%. Processing factors of etofenprox were 2.6-3.0 for the one-time spraying and 2.5-3.0 for the two-time spraying and those of fenitrothion were found to be 1.5-22 for the one-time spraying and 1.6-2.0 for the two-time spraying. First half-lives of etofenprox and fenitrothion in fresh and dried samples ranged from 5.0 to 6.3 and from 3.4 to 4.0 days, respectively. The third half-lives were found to be 15.0-18.9 and 10.2-12.1 days, respectively. CONCLUSION: Residual concentrations of the tested pesticides in the studied crop decreased, but those in the dried samples appeared to have increased. In addition, processing factor and half life were constant regardless of spraying times.

• Journal of Fashion Business
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• v.17 no.3
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• pp.48-57
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• 2013

This study was performed to quantitatively and qualitatively estimate the effect of keratin essence on hair protection against physicochemical damage. Damaged hairs were obtained from an early thirty woman who dyed her hair two times and did digital permanent treatment of her hair two times. The damaged hairs were divided into four experimental groups, which are the control hair (CH) group without additional beauty treatment, the damaged hair (DH) group by additional dyeing treatment, basic essence-treated hair (BEH) group, and keratin essence-treated hair (KEH) groups according to the research goal. The protection effect of keratin essence against the physicochemical damage was quantitatively compared by difference of chrominance measured using a color difference meter and qualitatively compared by difference of outer morphological structure images pictured using scanning electron microscopy (SEM). The brightness and yellowish blue color of KEH were relatively lower but the reddish blue color was relatively higher than other groups of test hairs. Cuticle structure of the previously DH was irregularly deformed and more strongly deformed or partially broken by additional dyeing treatment. On the other hand, the gaps between cuticle scales of the DH were reformed by treatment with basic essence and reformed and filled by treatment with keratin essence in comparison with the DH group. Conclusively, the keratin essence was effective to protect hair structure against the structural damage induced by the dyeing-treatment, by which the coloring efficiency is thought to be improved.

• 보존과학연구
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• s.31
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• pp.79-88
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• 2010

Paper cultural heritages experience chemical and physical deterioration due to various factors including preservation environments and the property of paper materials1). Thus, it is important to develop optimal preservation and restoration methods for the damaged paper cultural heritages. Currently, lining is a popular treatment for the restoration of paper cultural heritages in Korea. Since lining paper is a layer of paper directly attached to the inside of cultural heritages for protection, understanding of the preservation properties of lining paper is primarily needed in order to devise the better preservation methods. The main material of lining paper is the paper mulberry, but additives such as chalk and white clay is sometimes used to enhance the preservation properties of lining paper. To date, the properties of the functional lining paper containing these additives have been not fully understood yet. In this study, dry heating aging at $105^{\circ}C$ and biological aging by the Aspergillus versicolor and Penicillium polonicum for the lining paper, which is made from paper mulberry and the chalk, are carried out to evaluate changes in their preservation properties by these aging factors. As a result, it is found that the functional lining paper containing 25.1% of chalk can control the growth of fungi, while the paper containing 32.7% of chalk do not show any protection effect. However, the functional lining paper added by chalk is more aged than the lining paper made from paper mulberry by dry heating accelerated aging.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.4
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• pp.219-225
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• 2007

Bis-ethylhexyloxyphenolmethoxyphenyltrizine (BEMT) is one of the most widely used chemical UVA+UVB double absorbers in sunscreen products. But topical application of BEMT is restricted due to its defects in product. The purpose of this study is to adopt the sunscreen product of solid lipid nano-particles containing BEMT (BEMT-SLN). The particle diameters, the encapsulation efficiencies and the crystallization index (C.I.) are about 330nm, 93.3 % and the 4.3 %. As a result, in vitro penetration and release of BEMT were generally higher in O/W emulsion than the SLN formulation. However in vivo study, it was shown that the rate of release could be decreased by 80 % in the SLN formulation. The sun protection factor (SPF) of the SLN formulation increased by 100 % in the in vitro UV protection test. Therefore, SLN formulation potentiated the UV-blocking power of BEMT. This study suggest that SLN can be used for the encapsulation of BEMT.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.83-88
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• 2020

BACKGROUND: This study was carried out to investigate residual characteristics of diethofencarb during ginseng cultivation and processing, and to establish the maximum residue limits (MRL) of ginseng and its processed products. METHODS AND RESULTS: Supervised field trials were conducted from three fields located at Seosan, Goesan and Jeongeup in Korea. Diethofencarb 25% WP was diluted by 500 times and sprayed 4 times onto the ginseng with 10 days interval. The samples were collected at 80 days after final application. The residual amounts of diethofencarb ranged from 0.074 to 0.460 mg/kg in fresh ginseng, from 0.292 to 0.720 mg/kg in dried ginseng, and from 0.208 to 0.557 mg/kg in red ginseng. These data exceeded the ginseng's MRL, 0.3 mg/kg. The processing factors of diethofencarb in processed products were found to be 2.64 and 1.99, respectively for dried and red ginseng. CONCLUSION: Given the lower residual concentration of red ginseng that goes through a more complicated process than dried ginseng, the residual concentrations of diethofencarb in processed ginseng products were found to be dependent on processing method. Therefore, it is necessary to reconsider the MRL of diethofencarb in fresh ginseng and its processed products.