• Resources Recycling
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• v.14 no.1
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• pp.55-63
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• 2005

This study investigated the electrochemical recovery of palladium in a HCl solution that is used for palladium leaching. The high acidity of HCl solution and the low concentration of Pd ions increased the cathodic overpotential and reduced the limiting current density. Lowering the current density produced dense deposits; however, they were under high tensile stress. Raising the temperature affected both the densification and the stress, which enabled the attainment of dense Pd deposits under low stress. Lowering the current density and raising the temperature up to 70$^{\circ}C$ was recommended for the recovery of palladium as sound bulk Pd deposits. Current efficiency was over 85% at the initial stage of recovery may decrease the current efficiency, since a low Pd ion concentration results in a low limiting current density.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.507-511
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• 1995

Catalytic chlorination of chlorobenzene was studied in vapor phase using various solid-acid catalysts such as silica-alumina, alumina, zeolite and a modified clay prepared by impregnating bentonite with ferric chloride. The conversions of both chlorine gas and chlorobenzene showed high over silica-alumina, alumina and modified clay catalysts. However relatively large amounts of polychlorinated benzene derivatives were also observed. The active species of catalytic activity in chlorination of chlorobenzene in vapor phase were proved to be as Lewis acid sites by in-situ IR experiments. The strength of Lewis acid sites which were effective for the vapor-phase chlorination seemed to be having Hammett acidity Ho >-3.0. The selectivity to dichlorobenzenes was proved to be high over the zeolite catalyst due to their shape-selective properties. p-Dichlorobenzene or dichlorobenzene selectivities were improved more or less by changing the reaction conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.95-97
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• 2007

Our understanding on the plant's capability to acquire the nutrients from the soil under harsh circumstance, like unfavorably high pH, and the plant's capability to protect itself under very low soil pH, has been remarkably increased in the recent years. Having those knowledges, it seems not to be wise to abide to the traditional approach to deal the problems of acidic or alkaline soils via chemical methods like liming or using acidic materials. Instead, we may try to select the crops and varieties that can better withstand soil acidity or alkalinity. This stance will be more welcomed when the conservation of environments is high priority issue.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.79-84
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• 2016

A kimchi container actively controlling $CO_2$ concentration by timely flushing of $CO_2$ gas was structured and tested in its capability and effectiveness because high $CO_2$ concentration enhances the sensory flavor of the product. The inlet and outlet valves of $CO_2$ gas were programmed to open and close allowing synchronous vent/$CO_2$ flush according to the requirements of its dissolution in the contained kimchi. During the chilled storage, the headspace of container could be maintained at desired high $CO_2$ concentration providing the preferred kimchi in sensory quality compared to control of the conventional container. However, there was no significant difference between the high $CO_2$ container and control (container simply closed with air) in kimchi quality attributes of pH, titratable acidity, total viable bacterial count, Lactobacillus sp. count and Leuconostoc sp. count. The flow rate and time interval of $CO_2$ flushing need to be adjusted considering the kimchi amount, headspace volume and ripening time. The designed system has potential to be applied in refrigerator appliances in homes and food service industry.

• The Korean Journal of Food And Nutrition
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• v.20 no.4
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• pp.378-383
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• 2007

To study the characteristics and processing of Kochujang which is rapidly fermented by commercial enzymes, three kinds of Kochujang(KP-FA, KP-FN, and KP-BN) using commercial proteases and one Kochujang(KM) using Meju were prepared and their qualities investigated. There were only small differences in pH and acidity between each Kochujang. The moisture contents were high tendency in the three kinds of Kochujangs using the commercial proteases at 20 days of fermentation. Reducing sugars had a tendency to decrease during the fermentation in the Kochujangs using the proteases. During the first half of fermentation, the Kochujangs made with proteases showed higher amino nitrogen contents than the Kochujang(KM) made using Meju. Acidic protease activity was high in KP-FA at 20 days of fermentation and neutral protease activity was high in KP-FN and KP-BN at the beginning of fermentation. The Kochujangs made using the proteases, through 20 days of fermentation, obtained high preference in the sensory evaluation for color, texture, and overall acceptability. However, the hot taste was stronger in these Kochujangs during the fermentation.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.31-42
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• 1990

In order to suggest an efficient catalyst systems for NOx reduction of flue gases from industrial boilers, $TiO_2$ supported $WO_3-V_2O_5, V_2O_5$ and $WS_2$ catalysts were tested for the performances of NOx reduction at high reactin temperature range (250-500$^\circ$C) using a simulated flue gas system. It was found that while the proposed $WO_3/TiO_2$ and $WO_3-V_2O_5/TiO_2$ catalysts showed a significant high NOx reduction efficiency at about 350-400$^\circ$C, the conventional commercial catalyst of $V_2O_5/TiO_2$ showed a significant drop in NOx reduction efficiency due to the excessive $NH_3$ oxidation. From the measurement of surface acidities of those catalysts, it was found that the acidity are well correlated with the activities of NOx reduction. The reason of high activity of $WO_3$ series catalysts at high reaction temperature seems due to the low value of surface excess oxygen compared with that of $V_2O_5/TiO_2$ seems equivalent to the acid site of that catalyst.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.13-18
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• 2006

Mandarin juice was processed using a continuous high pressure $CO_2$ system. Response surface methodology was used to investigate the effects of the processing parameters such as temperature, pressure, residence time, and %(w/w) ratio of $CO_2$ to juice on total aerobic count (TAC), pectinesterase (PE) activity, cloud level, $^{\circ}Brix$, pH, and titratable acidity (TA) of the juices. Maximum log reduction (3.47) of TAC was observed at $35^{\circ}C$, 41.1 MPa, 9 min residence time, and 7% $CO_2$. PE was inactivated by 7-51%. The cloud was not only retained but was also enhanced by 38%. Lightness and yellowness increased, and redness decreased. The processing temperature and % $CO_2$/juice ratio significantly affected high pressure $CO_2$ processing of the juice in terms of pasteurization, PE inactivation, cloud increase, and color change. The $^{\circ}Brix$, pH, and TA before and after treatment remained unchanged.

• The Korean Journal of Ecology
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• v.21 no.5_1
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• pp.449-456
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• 1998

This study was carried out to investigate the characteristics of acid deposition by stemflow, throughfall, rainfall and $SO_{2}$ in the industrial, urban and rural areas where were affected by the acid rain areas air pollution in Pinus thunbergii than Quercus spp. forest. As the stemflow pH in industrial and urban area were lowed that of rural area, the result industrial and urban, and correlation of negative ($r=-0.9415^{**}$) between pH and EC. The concentration of acid ion by stemflow, throughfall, rainfall were high $SO_{4}^{2-}$ ion at industrial areas, especially of $NO_{3}^{-}$ ion at urban areas. The concentration of basic ion all rain fall were high $Ca^{2+},\;Na^{+}$ ion at industrial areas, but there were high $Ca^{2+}$, $Na^{+}$ ion at urban areas. The concentration of $SO_{2}$ at survey areas were high $SO_{2}$ concentration at industrial and urban areas, but there was low at rural areas. There was correlation of negative ($r=-0.8007^{**}$ between pH and $SO_{2}$ concentration at survey areas. Soil acidity was also affected by stemflow and showed sigificantly low pH in industerial and urban areas.

• Korean Journal of Food Science and Technology
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• v.48 no.6
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• pp.548-554
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• 2016

Since some strains of kimchi lactobacilli can curdle milk, they can be used for making yogurt. However, the best Lactobacillus plantarum strains for curdling milk for yogurt are still unknown. In this study, we determined the best L. plantarum strains for curdling milk, and the physicochemical properties of yogurts made using different L. plantarum strains were examined. Three strains of L. plantarum useful for curdling milk were identified (YD2, YD9, YD12). The number of lactobacilli was lower in yogurts made with L. plantarum than in those made with control, and among the L. plantarum strains tested, YD12 had the highest bacterial counts. However, the microbial count reached $6.3{\times}10^8CFU/mL$ after 24-h fermentation in all yogurts. The pH of the yogurts decreased after 12-h fermentation, while the acidity increased. The low pH and high acidity decreased the viscosity in all the three types of yogurts, because the acids disturbed gel formation due to protein denaturation. Sensory evaluation revealed that the YD12 group showed a high percentage of completion similar to the control group. YD2 and YD9 showed a high sourness value and low sweetness value, whereas YD12 yielded optimal values for all the organoleptic characteristics. Therefore, YD12 would be a high quality bacterial strain for use as a yogurt starter culture.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.2
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• pp.93-100
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• 2011

The study was conducted to investigate the correlation analysis between fruit quality and climatic parameters in grapevines. 'Campbell Early', one of the major grape cultivars, occupies more than 70% of cultivated areas in Korea. Recent research results have shown that the movement of cultivation area of fruit production resulted from the temperature increase. In this study, we investigated the relationship between fruit quality and climatic conditions in 13 major 'Campbell Early' grape producing areas (i.e., Sacheon, Jinju, Naju, Dangjin, Cheonan, Gimcheon, Yeongdong, Okcheon, Sangju, Suwon, Yeongju, Gangneung, Chuncheon, and Yanggu). The earliest and latest full blooming days of grapevines were ovserved on May 25 in Sacheon area and on June 7 in Yanggu area, respectively. At least 90 days are required for grapes to mature enough for the production of highquality fruits. The southern areas with less than 90 days of maturity period had difficulty in the production of good fruit. However, the areas with longer maturity period of 100 to 110 days produced grapes with with high sugar content and good coloring. The fruit qualities of 'Campbell Early' grapes are more closely related with temperature than other climatic factors. High temperature resulted in fruits with high acidity and delayed the coloration of the fruit skin in the southern area. The fruit skin was thin in the southern area and inclined to be thicker in the northern areas. Therefore, grape should be cultivated in regions with long maturity period to have high quality.