• 대기
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• 제28권2호
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• pp.153-162
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• 2018

The statistical prediction model for wintertime surface air temperature, that is based on snow cover extent and Arctic sea ice concentration, is updated by considering $El-Ni{\tilde{n}}o$ Southern Oscillation (ENSO) and Quasi-Biennial Oscillation (QBO). These additional factors, representing leading modes of interannual variability in the troposphere and stratosphere, enhance the seasonal prediction over the Northern Hemispheric surface air temperature, even though their impacts are dependent on the predicted month and region. In particular, the prediction of Korean surface air temperature in midwinter is substantially improved. In December, ENSO improved about 10% of prediction skill compared without it. In January, ENSO and QBO jointly helped to enhance prediction skill up to 36%. These results suggest that wintertime surface air temperature in Korea can be better predicted by considering not only high-latitude surface conditions (i.e., Eurasian snow cover extent and Arctic sea ice concentration) but also equatorial sea surface temperature and stratospheric circulation.

• Geomechanics and Engineering
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• 제21권2호
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• pp.153-164
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• 2020

Tunnel excavation in shallow soft ground conditions of urban areas experiences inevitable surface settlements that threaten the stability of nearby infrastructures. Surface settlements during shield TBM tunneling are related to a number of factors including geotechnical conditions, tunnel geometry and excavation methods. In this paper, a database collected from a construction section of Hong Kong subway was used to analyze the correlation of settlement-inducing factors and surface settlements monitored at different locations of a transverse trough. The Pearson correlation analysis result revealed a correlation between the factors in consideration. Factors such as the face pressure, advance speed, thrust force, cutter torque, twin tunnel distance and ground water level presented a modest correlation with the surface settlement, while no significant trends between the other factors and the surface settlements were observed. It can be concluded that an integrated effect of the settlement-inducing factors should be related to the magnitude of surface settlements.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2002년도 춘계 공동학술발표회
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• pp.59-61
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• 2002

• Environmental Engineering Research
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• 제24권1호
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• pp.173-179
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• 2019

Prussian blue (PB) is known to be an effective material for radioactive cesium adsorption, but its nano-range size make it difficult to be applied for contaminated water remediation. In this study, a simple and versatile approach to immobilize PB in the supporting matrix via surface functionalization was investigated. The commercially available poly vinyl alcohol (PVA) sponge was functionalized by acrylic acid (AA) to change its major functional group from hydroxyl to carboxylic, which provides a stronger ionic bond with PB. The amount of AA added was optimized by evaluating the weight change rate and iron(III) ion adsorption test. The FTIR results revealed the surface functional group changing to a carboxyl group. The surface functionalization enhanced the attachment of PB, which minimized the leaching out of PB. The $Cs^+$ adsorption capacity significantly increased due to surface functionalization from 1.762 to 5.675 mg/g. These findings showed the excellent potential of the PB-PAA-PVA sponge as a cesium adsorbent as well as a versatile approach for various supporting materials containing the hydroxyl functional group.

• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.878-881
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• 2002

The goal of the current research was to assess the influence of the growth rate of Nocardia amarae on its overall metal binding capacity. Batch sorption isotherms for cadmium (Cd), copper (Cu), and nickel (Ni) showed that Nocardia cells harvested from chemostat cultures at a dilution rate of $0.33d^-1$ had a significantly higher metal sorption capacity than cells grown at 0.5 and $1d^-1$. The cell surface area estimated using a dye technique indicated that pure N. amarae cells grown at a lower growth rate had a significantly more specific surface area than cells harvested from a higher growth rate operation. Accordingly, this difference in the specific surface area seemed to indicate that the higher metal sorption capacity of the slowly growing Nocardia cells was due to their higher specific surface area.

• Environmental Engineering Research
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• 제24권3호
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• pp.412-417
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• 2019

This paper presents the results of using cold plasma to treat surface water for domestic use purpose. Experimental results showed that cold plasma was an effective method for destroying bacteria in water. After treatment with cold plasma, concentration of coliform and Escherichia coli dramatically reduced. Besides, cold plasma significantly removed water odor, increased dissolved oxygen and decreased the concentration of chemical oxygen demand. However, cold plasma significantly raised the concentration of nitrite and nitrate. Other disadvantages of treating with cold plasma were conductivity increase and pH reduction. Pretreatment steps of coagulation, flocculation, sedimentation and sand filtration followed by disinfection with cold plasma exhibited a high efficiency in surface water treatment. All parameters of surface water after treatment by using the prototype satisfied with the allowance standard of domestic water quality.

• 한국환경과학회지
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• 제17권8호
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• pp.919-924
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• 2008

The surface properties and adsorption rates of activated carbon modified with acid and base were compared. The distribution ratio of C and C-H on the surface of activated carbon were decreased by modification with acid and base, but the distribution ratio of C-O, C=O, and O=C-O were increased. Base modification damaged the surface of activated carbon more than acid modification, it caused the effect of 6 percent increments of surface area. Adsorption rate model was more suitable to second order equation than first order equation. Adsorption rate was controlled by adsorption in pore better than in surface.

• Environmental Engineering Research
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• 제8권2호
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• pp.91-97
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• 2003

• 한국지하수토양환경학회지:지하수토양환경
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• 제28권6호
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• pp.16-23
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• 2023

Heavy metal (Zinc, Cadmium, Lead) adsorption onto surface modified activated carbon was performed in order to better understand the effect of sodium ion addition to activated carbon. Surface modification methods in this research included water washing, nitric acid washing, and sodium addition after nitric acid washing. These surface modifications generated oxygen functional groups with sodium ions on the surface of the activated carbon.. This caused the change of the specific surface area as well as in the ratio of the carboxyl groups. Heavy metal adsorption onto sodium-containing activated carbon was the most among the three modifications. After the adsorption of heavy metals, the carboxyl group ratio decreased and sodium ions on the surface of the activated carbon were almost non-existent after the adsorption of heavy metals onto sodium-containing activated carbon. The results from this research indicated that ion exchange with sodium ions in carboxyl groups effectively improved heavy metal adsorption rather than electrostatic adsorption and hydrogen ion exchange.

• 한국환경과학회지
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• 제20권8호
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• pp.963-975
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• 2011

For this research, they were monitored $CO_2$ flux and environmental factors ($CO_2$ concentration, soil temperature, soil moisture, soil organic carbon, soil pH, soil Eh) in foreshore, paddy field and woods sites at the winter season (January 2009) and the summer season (September 2009). Seasonal and spatial variations for monitored data were analyzed, and linear regression functions of $CO_2$ flux as environmental factors were estimated. $CO_2$ fluxes averaged between surface and atmosphere monitored in foreshore and paddy field at the winter season were shown $-8\;mgCO_2m^{-2}hr^{-1}$ and $-25\;mgCO_2m^{-2}hr^{-1}$, respectively. $CO_2$ fluxes averaged between surface and atmosphere monitored in foreshore and paddy field at the summer season were shown $47\;mgCO_2m^{-2}hr^{-1}$ and $117\;mgCO_2m^{-2}hr^{-1}$, respectively. Thus, $CO_2$ was sunk from atmosphere to surface at the winter season and it was emitted from surface to atmosphere at the summer season. $CO_2$ fluxes in woods site were emitted $145\;mgCO_2m^{-2}hr^{-1}$ at the winter season and $279\;mgCO_2m^{-2}hr^{-1}$ at the summer season.