• Journal of Korean Society of Environmental Engineers
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• v.33 no.5
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• pp.332-339
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• 2011

Effects of powdered activated carbon impregnated by iron oxide nano particle (Impregnated PAC) on the microfiltration (MF) membrane system performance in NOM removal from water were investigated in this study. A fluidized bed column was employed as a pretreatment of MF membrane process. The Impregnated PAC bed was stably maintained at an upflow rate of 63 m/d without leakage of the Impregnated PAC particles, which provided a contact time of 29 minutes. A magnetic ring at the upper part of the column could effectively hold the overflowing discrete particles. The Impregnated PAC column demonstrated a significant enhancement in the MF membrane performance in terms of fouling prevention and natural organic matter (NOM) removal. Trans-membrane pressure of the MF membrane increased to 41 kPa in 98 hours of operation, while it could be maintained at 12 kPa with the Impregnated PAC pretreatment. Removal of NOM determined by dissolved organic carbon and UV254 was also enhanced from 46% and 51% to 75% and 84%, respectively, by the pretreatment. It was found that the Impregnated PAC effectively removed a wide range of different molecular-sized organic compounds from size exclusion analysis.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.190-198
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• 2008

In this stduy, the column experiments were carried out assuming the soil was contaminated by leakage of gasoline containing MTBE from USTs and pipes around gas stations. Then, characteristics of MTBE transport in the soil were investigated using CXTFIT program. The column experiments with different soil properties, moisture content, organic matter content and flow rate were carried out. Some parameters(D, R, $\beta$, $\omega$) used in two-site non-equilibrium adsorption model were obtained from measuring the MTBE concentration in injection-liquid and in effluent and using CXTFIT program. In addition, The characteristics of MTBE transport in the soil was found using BTCs and obtained parameters. Consequently, the advection decreased as the increase of the content of fine particle and organic, while the MTBE transport by advection was enhanced as increasing flow rate and moisture content.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.44-49
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• 1990

The quality of garlic powder produced by hot all drying and freeze drying method was evaluated Porapak Q column was comparatively profitable for the separation of flavor components in hexane extracts of garlic. Freeze dried (FD) garlic powder had higher diallyl disulphide, total pyruvic acid and alliin than hot air dried (HD) garlic powder. On the results of color evaluation by color difference meter, garlic powder of HD were more brownish than FD. In microstructure of garlic powder observed by SEM, freeze dried garlic powder was fairly porous.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1095-1101
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• 2008

Nonaqueous phase liquids (NAPL) are the continuous source for soil and groundwater contamination. The first objective of the study was to verify the effect of co-injection of cosolvent and air on NAPL removal from soil-column system. The second objective of the study was to investigate the effect of alcohol-partitioning property on the NAPL removal by the co-injection process of cosolvent and air. Enhanced removal of benzene-NAPL by the co-injection process of ethanol and air was also verified within the soilcolumn system. However, the co-injection process of Tert-butanol (TBA) and air showed no enhancement of benzene-NAPL removal. This study found that the viscous pressure of TBA was so higher than the capillary pressure and TBA easily displaced the benzene-NAPL and air present in soil pores. Air of the coinjection process did not work for NAPL removal but hindered NAPL mobilization. NAPL partitioning property and viscous pressure of cosovlent should be considered for application of the co-injection process of cosolvent and air.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.2
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• pp.37-45
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• 2008

In this study, reliabilities of Cu (60 um)/SnAg (20 um) double-bump flip chip assemblies were investigated for the flip chip interconnections on organic substrates with 100 um pitch. After multiple reflows at $250^{\circ}C\;and\;280^{\circ}C$, bump contact resistances were almost same regardless of number of reflows and reflow temperature. In the high temperature storage test, there was no bump contact resistance change at $125^{\circ}C$ up to 2000 hours. However, bump contact resistances slightly increased at $150^{\circ}C$ due to Kirkendall voids formation. In the electromigration test, Cu/SnAg double-bump flip chip assemblies showed no electromigration until about 600 hours due to reduced local current density. Finally, in the thermal cycling test, thermal cycling failure mainly occurred at Si chip/Cu column interface which was found out the highest stress concentration site in the finite element analysis. As a result, Al pad was displaced out under thermal cycling. This failure mode was caused by normal compressive strain acting Cu column bumps along perpendicular direction of a Si chip.

• Korean journal of communication and information
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• v.70
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• pp.221-245
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• 2015

This research defines Pope Francis's visit to Korea in August 2014 and the reactions from journalism to it as a case to show the discursive potential of mediated religion for social change. It analyzes the editorials and the columns on the Pope in five daily newspapers including the Chosunilbo, the Dong-A Ilbo, the Joongang Daily, the Hankyoreh, and the Kyunghyang Shinmun. Since the Pope receives positive evaluations for his remarks and behaviors during the visit from most of those articles, this research categorizes the values identified with the Pope and those with the "anti-Pope" into a form of binary oppositions, and interpret the meanings of the rhetorical strategies. The findings suggest that a consistent narrative is constructed by journalism regarding the harsh reality of Korea and the ways to overcome its structural problems. Based on the findings, I argue that mediated religion in this case is expected by the secular society to do its role for social change by being a provider of progressive and alternative values.

• Journal of the Korean Geosynthetics Society
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• v.22 no.2
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• pp.13-21
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• 2023

Mean sea level has recently been rising due to global warming causing coastal erosion. As Korea is peninsula, the land loss due to coastal erosion is critical. An approach in this study is cementing the coastal area using bacteria, which is called microbially induced carbonate precipitation (MICP). This study tried to see how fresh water and sea water work with MICP as a solvent. Ureolytic activity during the MICP reaction was measured with deionized and sea water. A soil column was prepared to evaluate the strength of MICP-treated sand. Sands were treated by MICP with surface percolation method. As the treatmen t style was different with other conventional methods, several methods were proposed to properly evaluate the MICP-treated sand surface. A micro-scale evaluation was performed to assess the mineral structure treated by different solvents. As results, sea water rendered the ureolytic reaction slower. A needle penetrometer worked well to evaluate the MICP-treated sand surface. This study confirmed the utilization of sea water is feasible as the solvent of MICP.

• Journal of Mushroom
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• v.20 no.4
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• pp.263-269
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• 2022

This study investigated the culture characteristics of Cryptoporus volvatus, whichis grow naturally in Korea, to determine the suitable environmental conditions for its cultivation. The physiological characteristics of the mycelia were assessed according to the cultivation conditions, to determine the optimal conditions for artificial cultivation. The visual characteristics of the hyphae of Cryptoporus volvatus KACC52303 included an irregular and uneven surface and a fuzzy or cotton-like texture. Under the microscope, its microstructure showed pre-chlamydospore formation, but no clamps were seen. The appropriate culture temperature was found to be a medium/high temperature of approximately 25-30℃, and the optimal pH was found to have a wide range from weakly acidic (pH 4) to neutral (pH 7). In the optimal nutrient source experiment, hyphal growth was shown to be fair in a mixed medium with 2.5% dextrin as the carbon source and 0.1% yeast extract as the organic nitrogen source. Among the various amino acids, organic acids, and inorganic salts tested, the fastest hyphal growth was observed in the presence of leucine, acetic acid or gluconic acid, and KCl or KH₂PO₄, respectively. The column test showed that the best mycelial growth occurred in a mixed medium of 80% pine sawdust, 10% rice bran, and 10% corncob sawdust.