• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.98-104
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• 1997

Soil pollution intensity at Mt. Namsan in Seoul city which was expected to show significant soil contamination due to long-term air pollution was evaluated by comparing soil chemical properties at Mt. Kyebangsan in Hongcheon area as a control, and the bacteria participating in nitrogen or sulfur mineralization were assayed simultaneously in order to evaluate the validity of N and/or S mineralization bacteria as an index of soil contamination. The soil of Mt. Namsan showed 10 times higher concentration of hydrogen ion compared to that of Mt. Kyebangsan, which indicated that the soil had relatively been acidified seriously. Especially, large amount of canons were thought to be leached out from the soil, while the amount of extractable Al was getting larger and larger, which result in serious problems in soil ecosystem of the mountain. I could infer from soil chemical properties of the four study sites that the major reason of soil acidification was SOx deposition. However, the sulfur-reducing bacteria were not significantly different between the two regions, which indicated that the microbial dynamics of the soil ecosystem was not controlled by simple factor, but by multiple factors. By the way, the dynamics of bacteria participating in denitrification process was different between the two regions, which was more active at Mt. Kyebangsan than at Mt. Namsan. Thus, the microbial assay for nitrogen mineralization is desirable to be examined as a tool for evaluating soil health or microbial activity in soil ecosystem.

• Food Science and Industry
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• v.50 no.2
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• pp.2-11
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• 2017

Packaging is the last defensive barrier that protects food products from insect infestation during storage. However, though packaging films are hermetically sealed, insects can still be attracted by strong olfactory cues and penetrate through packaging materials, resulting in contamination. Insect contamination may cause consumers to be repulsed by contaminated food products. Especially, it is well known that stored-product insects cause critical problems in the cereal industry by inducing quantitative and qualitative damages to the grain products. The contaminations are caused by insects' metabolic byproducts and body parts, consequentially caused customer repulsion. Therefore, it is necessary to repel and control insects. However, management systems for storage insects in food industry have been inadequate for many years. Synthetic pesticides has been widely used, but pesticides may accumulate in foods, causing acute and chronic symptoms in consumers. For this reason, there is a growing need for the development of natural insecticides that can replace synthetic pesticides. Thus, various reports about anti-insect packaging materials and strategies to repel insects were introduced in this study. Furthermore, we suggested new strategies to develop an insect-repelling active packaging materials which could be applied in the food packaging industry.

• Structural Engineering and Mechanics
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• v.62 no.2
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• pp.197-208
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• 2017

Among various retrofitting strategies, use of semi-active control for retrofitting a building structure has gained momentum in recent years. One of the techniques for such retrofitting is to connect a weaker building to an adjacent stronger building by semi-active devices, so that performances of a weaker building are significantly improved for seismic forces. In this paper, a ten storey weaker building is connected to an adjacent stronger building using magneto-rheological (MR) dampers, for primarily improving the performance of the weaker building in terms of displacement, drift and base shear. For this, a fuzzy logic controller is specifically developed by fuzzyfying the responses of the coupled system. The performance of the control strategy is compared with the passive-on and passive-off controls. Pounding Mitigation between the two buildings is also investigated using all three control strategies. The results show that there exists a fundamental frequency ratio between the two buildings for which maximum control of the weaker building response takes place with no penalty on the stronger building. There exists also a fundamental frequency ratio where control of the weaker building response is achieved at the expense of the amplification of the stronger building. However, coupling strategy always improves the possibility of pounding mitigation.

• Journal of Environmental Science International
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• v.17 no.1
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• pp.119-128
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• 2008

Laboratory analytical results of 22 sets of hydrophobic adsorbent coils containing surface soil-vapor and two soil samples collected by conventional intrusive method from each boring location at two active dry cleaning facilities in the State of Illinois, U.S.A, were presented to evaluate the performance of soil-vapor survey. The most critical factor to determine the effectiveness of soil-vapor survey is the distance from the soil-vapor sampling device to the actual contamination, which is a function of soil porosity, permeability, primary lithology, and other geological and hydrogeological site-specific parameters. Also this factor can be affected by the history of contaminant-generating operations. The laboratory analytical results in this study showed longer dry cleaning operation history (i.e., 50 years) and presence of fine sand at the beneath Site B allow the contaminants to migrate farther and deeper over a fixed time compared to Site A(i.e., 35 years and silty clay) so that the soil-vapor survey is not likely the most effective environmental site investigation method alone for Site B. However, for Site A, the soil-vapor survey successfully screened the site to identify the location reporting the highest soil concentration of chlorinated solvents.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.45-47
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• 2017

The Infrared Camera onboard the AKARI satellite carried out spectroscopic observations with a grism mode named NG, whose wavelength coverage was $2.5-5.0{\mu}m$. We reinvestigate the current flux calibration for the NG grism mode, with which calculated flux density implausibly decreases at $4.9{\mu}m$ especially for red objects due to the second-order light contamination. We perform a new spectral response calibration using blue and red standard objects simultaneously. New response curves which contain both the first-and second-order light are able to separate each contribution consistently and useful for studies of red objects such as CO ro-vibrational absorption in active galactic nuclei.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.422-425
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• 2005

Spectral characteristics depending on soil constituents and their proportion in a soil were firstly studied for monitoring of soil contamination using hyperspectral remote sensing. The reflectance spectra of heavy metals in soils were investigated in the VIS-NIR-SWIR regions (400-2500 nm) to observe spectral variation as a function of constituents and concentrations. Commercial kaolinite soils mixed with lead, copper, arsenic, and cadmium were used as synthetic soil samples for spectral measurement. In case of copper, relatively spectrally active regions was observed with some band shift whereas other heavy metals had only simple spectral variations expected to be related to the sorption phase and the amount of metal onto kaolinite. The reflectance spectrum of each metal on kaolinite could be identified in VIS-NIR region.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.5-8
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• 1978

Numerical changes of coliform bacteria in a recirculating aquarium were measured as fouling indicator. The contamination of the filter bed was mainly due to the food given to fishes, the fecal materials and the additional supply of water polluted already. Abundance of the bacteria in the aquarium was controlled by the physiochemical factors of water quality. Of these factors, pH was the main factor. Under the water temperature $20^{\circ}C$, if pH was controlled at lower than $5\~6$, the bacteria did not flourish seriously. Under the water temperature over $30^{\circ}C$, the bacterial growth was markedly decreased regardless of the pH value, and the bacterial flora seemed to be active in growth under temperature condition lower than $30^{\circ}C$.

• Korean Journal of Community Nutrition
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• v.5 no.1
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• pp.100-108
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• 2000

Seven constructs of sanitary management :time temperature, storage, cross-contamination, personal hygiene, equipment facility and documentation management were evaluated to investigate the perceived performance of sanitary management for school food service managers, Using a four-part questionnaire containing the seven constructs of sanitary management HACCP program, demographic information and characteristics of food service facilities participants rated their self-perceptions regarding sanitary management. Of the 550 possible respondents, 248(45.1%) completed the study. For the perceived sanitary manage-ment variables, the participants rated them between 2.66 and 4.16(5-point Likert scale). Temperature management presented the lowest performances while storage management showed the highest. The number of years of work experience of the food service managers and the serving location correlated significantly to sanitary management variables. Documentation management was also highly correlated to the other sanitary management constructs. The respondents ranked the managers leadership and professional knowledge regrading HACCP as most important, followed by the facilitys supporting equipment and human resources second, to successfully implement the HACCP system at the school food service facilites, Awareness of this study indicating low performance on temperature management suggests an active training program is needed for sanitary management of school food service.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.167-172
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• 2020

The effectiveness of in situ sediment capping as a technique for heavy metal risk mitigation in Hyeongsan River estuary, South Korea was studied. Sites in the estuary were found previously to show moderate to high levels of contamination of mercury, methylmercury and other heavy metals. A 400 m x 50 m section of the river was selected for a thin layer capping demonstration, where the total area was divided into 4 sections capped with different combinations of capping materials (zeolite, AC/zeolite, AC/sand, zeolite/sand). Pore water concentrations in the different sites were studied using diffusive gradient in thin film (DGT) probes. All capping amendments showed reduction in the pore water concentration of the different heavy metals with top 5 cm showing %reduction greater than 90% for some heavy metals. The relative maxima for the different metals were found to be translated to lower depths with addition of the caps. For two-layered cap with AC, order of placement should be considered since AC can easily be displaced due to its relatively low density. Investigation of methylmercury (MeHg) in the site showed that MeHg and %MeHg in pore water corresponds well with maxima for sulfide, Fe and Mn suggesting mercury methylation as probably coupled with sulfate, Fe and Mn reduction in sediments. Our results showed that thin-layer capping of active sorbents AC and zeolite, in combination with passive sand caps, are potential remediation strategy for sediments contaminated with heavy metals.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1590-1595
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• 2009

Alternative methods for controlling bacterial endospore contamination are desired in a range of industries and applications. Attention has recently turned to natural products, such as essential oils, which have sporicidal activity. In this study, a selection of essential oils was investigated to identify those with activity against Bacillus subtilis spores. Spores were exposed to 13 essential oils, and surviving spores were enumerated. Cardamom, tea tree, and juniper leaf oils were the most effective, reducing the number of viable spores by 3 logs at concentrations above 1%. Sporicidal activity was enhanced at high temperatures ($60^{\circ}C$) or longer exposure times (up to 1 week). Gas chromatography-mass spectrometry analysis identified the components of the active essential oils. However, none of the major oil components exhibited equivalent activity to the whole oils. The fact that oil components, either alone or in combination, did not show the same level of sporicidal activity as the complete oils suggested that minor components may be involved, or that these act synergistically with major components. Scanning electron microscopy was used to examine spores after exposure to essential oils and suggested that leakage of spore contents was the likely mode of sporicidal action. Our data have shown that essential oils exert sporicidal activity and may be useful in applications where bacterial spore reduction is desired.