• Journal of the Korean Society of Groundwater Environment
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• v.6 no.1
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• pp.8-13
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• 1999

This research was investigated to examine the status of goundwater contamination in Chung-Nam area over 2 years from 1996 May to 1998 May. The results show that the overall detection rates of VOCs (volatile organic compounds) by region were as followed: industrial region > agricultural & industrial complex region > gas station region > around industrial region > downtown region, and excess rates of those were as followed: industrial region > gas station region > agricultural & industrial region > around industrial region > downtown region. Benzene and TCE of VOCs examined in Chon-An industrial region exceeded drinking water standard. At the agricultural & industrial complex region, the observed mean concentration of TCE was 3.107 mg/L and TCE was also detected at 48.152 mg/L which is 100 times higher than drinking water standard, and other VOCs were also observed at higher concentrations as well. Based on our studies, It is concluded that appropriate remedial action should be performed to protect further groundwater contamination and to restore groundwater quality in Chung-Nam area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.930-940
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• 2013

We evaluated contamination with organic matter and trace metals by analyzing grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Ni, Cr, Mn, Hg, and As) in surface sediments at 28 stations around the Geum River estuary in July 2008. The surface sediments in the estuary were mainly composed of coarse sediment (sand and muddy sand), with mean grain size (Mz) ranging between $2-4{\O}$. The high concentrations of IL, COD, and trace metals were mainly found at stations in front of the Gusan outer port and industrial complex, and near the Seocheon coast with relatively fine sediments. In addition, the concentrations of IL and all trace metals, except Pb and As, showed good positive correlations with Mz, indicating that the concentrations of organic matter and trace metals were mainly dependent on sediment grain size. The concentrations of COD, AVS, and trace metals in most sediments did not exceed the sediment quality guideline (SQGs). Although the sediments in the study region are not polluted with organic matter and trace metals, there are many point sources of pollutants, such as Gusan port and industrial complex, Janghang refinery, and a thermoelectric power plant around the Geum River estuary. Thus, the management of coastal environments through periodic monitoring of organic matter and trace metals is required in the future.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.435-439
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• 2004

Three Bacillus strains were isolated from soil samples. Morphological and physiologi­cal characterization indicated that the isolated strains were B. mycoides, B. licheniformis and B. brevis. White pepper was produced from black pepper by the fermentative method using the isolates in shake flaks as well as in a large-scale fermenter. Volatile oil and piperine contents of the product were $3.2\%$ (v/w) and $4\%$ (v/w) respectively. The moisture content was $15\%$. The mi­crobial contamination was less than 10 per 100 g. The product also exhibited excellent storage stability.

• Analytical Science and Technology
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• v.8 no.4
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• pp.829-834
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• 1995

Whole column coldtrapping(WCC) on a fused silica capillary (FSCC)combined with GC/MS analysis was evaluated for use in the investigation of volatile organic compounds(VOCs) in indoor air. Research had indicated that a temperature of $-80^{\circ}C$ is optimal for WCC. Samples were analyzed on a $50m{\times}0.2mm$ cross-linked 5% phenylmethylsilicone fused silica column. Liquid nitrogen was used as the coolant for the peak resolution significantly. The analysis can be performed quickly and conveniently. More than 112 of VOCs were determined in the samples from three typical indoor environment including: (1) a room which had just been decorated involving building materials and paints; (2)a kitchen used for Chinese cooking, and (3) a room had tobacco smoke. The method is could be readily applied to rapid sample screening for VOCs contamination surveys or initial investigations with its valid and simple sampling and analytical technique.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.6-12
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• 2005

Contamination of soils and groundwater by leakage of petroleum compounds from underground storage tanks (USTs) has become great environmental issues. Conventional methods such as soil vapor extraction (SVE) used for the remediation of unsaturated soils contaminated with volatile organic compounds might not be applied for the removal of semi-volatile organic compounds such as diesel fuels and PCBs, which have low volatility and high hydrophobicity. The objective of this study is to develop a hot air injection method to remove semi-volatile compounds. Additionally, operation parameters such as temperature, air flow rate, and water content are evaluated. Experimental results show that diesel ranged organics (DROs) are removed in the order of volatility of organic compounds. As expected, removal efficiency of organics is highly dependent on the temperature. It is considered that more than $90\%$ of organic contaminants whose carbon numbers range between 17 and 22 can be removed efficiently by the hot air injection-extraction method (modified SVE) over the $100^{\circ}C$. It is also found that increased air flow rate resulted in high removal rate of contaminants. However, air flow rate over 40 cc/min is not effective for the operation aspects, due to mass transfer limitation on the volatilization rate of the contaminants. The effect of the water content on the decane removal is minimal, but some components show large dependence on the removal efficiency with increasing water content.

• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.425-430
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• 2015

The objective of the study was to investigate the off-flavor generated from PET water bottles and their caps by using a mass spectrometry-based electronic nose. The ion fragment data obtained from the electronic nose were used for discriminant function analysis (DFA). In the case of increased concentrations of the contamination of water, the off-flavor pattern depended on the discriminant function second score instead of the discriminant function first score. To identify the cause of off-flavor in polyethylene terephthalate (PET) bottled water, the PET bottle and its cap were analyzed by DFA. The results showed that the cap generated more volatile compounds than the bottle or mineral water did. The substances causing the off-flavor were predicted to be 2,4-di-tert-butylphenol (2,4-DTBP), nonanal, and decanal when the main peak of the mass spectrum was compared with the major ion fragments of the electronic nose. Thus, using this method, we could determine whether the PET water bottle was contaminated and whether the off-flavor resulted from contamination of the bottle cap.

• Journal of the Korean Society for Railway
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• v.11 no.2
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• pp.182-187
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• 2008

The environmental significance of indoor air quality is gaining more attention. Especially, the contamination of indoor air by volatile organic chemicals (VOCs) has become a serious environmental concern. We investigated the VOCs emissions from some interior materials used in the conventional railway passenger cabin. The seat cover and the flooring of cabins were used as testing materials, and they were put in a clean environmental chamber. The temperature and relative humidity was kept at $25{\pm}1^{\circ}C$ and $50{\pm}5%$, respectively. It was found that these interior materials emitted significant amount of VOCs under constantly ventilated condition. The flooring emitted more halogenated VOCs than the seat cover, because it is made of PVC, which contains many chlorine atoms. However, the emission gradually decreased over time. Because the VOCs emission from interior materials may threaten the health of passengers in the cabin, interior materials emitting less VOCs should be used.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.2
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• pp.104-113
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• 2012

Crab-like flavorants (CFs) were made from snow crab cooker effluent (SCCE) using response surface methodology (RSM) and reaction flavoring technology (RFT). Type A CF was made from SCCE via RSM, RFT, adding starch syrup, centrifugation, and microfiltration. Type B was made from type A by adding the food additives dimethyl sulfide, ethyl valerate and fish sauce. The stability of the CFs was evaluated in terms of the color values, sensory evaluation, and flavor profiles after storage for 90 days at three different temperatures: 10, 20, and $30^{\circ}C$. The compounds, ethanol and 3-methyl-1-butanol, were considered key components of off-flavor and a decrease in dimethyl-2-vinylpyrazine affected the occurrence of off-flavor. It may be a microbial metabolite arising from contamination and lab-scale micro-filtration. At the lowest temperature ($10^{\circ}C$), the decrease in volatile compounds, such as pyrazines, was not as dramatic as at $20^{\circ}C$ and $30^{\circ}C$ and alcohol formation was prevented or delayed. Therefore, it is necessary to store CFs at < $10^{\circ}C$ with suitable sterilization to preserve volatile flavor compounds and prevent off-flavor from occurring.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1617-1622
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• 2006

Long-term storage of feeds or feedstuffs in high temperature and humid conditions can be difficult because of microbial contamination. Essential oil isolated from industrial waste citrus peel could be used as a preservative because it is likely to have anti-bacterial and anti-fungal activity. Our objective was to determine whether different levels (0.028, 0.056 and 0.112 g/kg) of citrus essential oil (CEO) would provide anti-microbial activity and enhance preservation of animal feed without influencing rumen fermentation. At 0.112 g/kg, CEO inhibited growth of Escherichia coli (ATCC 25922) and Salmonela enteritidis (IFO 3313). Growth of E. coli recovered after 24 h of incubation, but S. enteritidis continued to be inhibited for 72 h. Preservation of antibiotic-free diets for swine was assessed by observing anti-aflatoxin activity. Aflatoxin was detected in control feed samples on days 16 (8 ppb) and 21 (8 ppb) and in anti-fungal agent (AA) treated samples on days 16 (2 ppb) and 21 (4 ppb). However, aflatoxin was not detected in feed samples treated with CEO. Treatment with CEO and AA did not influence ruminal pH, dry matter digestibility (DMD) or organic matter digestibility (OMD) over 48 h of incubation in rumen fluid. Acetate and propionate were slightly higher with CEO treatment (p<0.05), but total concentration of volatile fatty acid (VFA) was not significantly affected by treatment. Ammonia-N concentration was slightly higher for the control treatment (p<0.05). This study showed that treating feed with CEO enhances preservation of animal feed without influencing in vitro rumen fermentation.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.38.1-38.1
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• 2009

Plasma etching is an essential process for electronic device industries and the particulate contamination during plasma etching has been interested as a big issue for the yield of productivity. The oxynitride glasses have a merit to prevent particulate contamination due to their amorphous structure and plasma etching resistance. The YSiAlON oxynitride glasses with increasing nitrogen content were manufactured. Each oxynitride glasses were fluorine-plasma etched and their plasma etching rate and surface roughness were compared with reference materials such as sapphire, alumina and quartz. The reinforcement mechanism of plasma etching resistance of the YSiAlON glasses studied by depth profiling at plasma etched surface using electron spectroscopy for chemical analysis. The plasma etching rate decreased with nitrogen content and there was no selective etching at the plasma etched surface of the oxynitride glasses. The concentration of silicon was very low due to the generation of SiF4 very volatile byproduct and the concentration of aluminum and yttrium was relatively constant. The elimination of silicon atoms during plasma etching was reduced with increasing nitrogen content because the content of the nitrogen was constant. And besides, the concentration of oxygen was very low on the plasma etched surface. From the study, the plasma etching resistance of the glasses may be improved by the generation of nitrogen related structural groups and those are proved by chemical composition analysis at plasma etched surface of the YSiAlON oxynitride glasses.