• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.808-814
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• 1989

To produce ${\gamma}-linolenic$ acid by a mold, cultural conditions of Mortierella isabellina IFO 8183 were investigated. It was found that the increase of initial pH resulted in the decrease of the ${\gamma}-Linolenic$ acid content and the increase of the C/N ratio of medium resulted in the increase of the lipid content. Addition of sodium acetate into the medium resulted in the increased of cell yield, lipid yield, ${\gamma}-Linolenic$ acid content and ${\gamma}-Linolenic$ acid productivity. Under the optimum coditions(glucose, $NH_4NO_3$, C/N ratio of 40, pH 6.0, $30^{\circ}C$ and 0.5% of sodium acetate), the following results were obtained: cell yield, 0.347(g dry biomass/g glucose; lipid yield, 0.18(g lipid/g glucose); lipid content, 0.52(g lipid/g dry biomass); ${\gamma}-linolenic$ acid content, 60(mg ${\gamma}-linolenic$ acid/g lipid); maximum ${\gamma}-linolenic$ acid concentration, 347mg/l after incubation of 8 days.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.135-140
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• 1988

This field experiment was carried out to determine the effects of cutting times (3,4 and 5 times $yr^{-1}$) and cutting heights (3, 6 and 9 cm) on the growth and dry matter(DM) yield of grasses grown under pine trees, and botanical composition of woodland pasture. The conditions of the experimental field was south direction with 30% of shade (ca. 70% of full sunlight). Annual DM yield was higher in the plots cut 4 times (6,097 kg) and 3 times (5,953 kg) than in 5 times (5,305 kg $ha^{-1}$). However, it ip considered that total nutrient yields may be not different among 3 treatments. The yield was significantly (P < 0.05) increased with higher cutting height, regardless of cutting time. The 9 cm of stubble height was very effective on both increasing DM production and seasonal distribution of DM. In botanical composition, 3 cm and 6 cm of cutting height accelerated the percentages of bareland and weeds, regardless of cutting time, particularly in summer season. However, 9 cm of stubble height maintained 80-85% of pasture grasses in all cutting times. In this experiment, therefore, cutting height was more important factor than annual cutting times for forage production and pasture longevity, and it is desirable to harvest 4-5 times per year (under this experimental field condition) with 9 cm of stubble height on woodland pasture.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.4
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• pp.329-336
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• 2009

This experiment was carried out to know adaptability and forage production and quality of corn hybrid for silage at paddy field from 2007 to 2008 at Chungnam province. Growth, forage production and quality of silage corn showed more well drained condition than poorly drained condition at paddy field. Among growth characteristics, 'Kwangpyongok' and 'DK697' hybrids were somewhat strong for waterlogging, then and good at stay green, lodging, disease and insect resistance. Fresh yield of 'DK697' hybrid at poorly drained paddy field was the highest as 32,610 kg per ha among corn hybrids. The dry yield of 'P32P75' hybrid at poorly drained paddy field was the highest as 14,910 kg per ha The result of this study showed that 'P32P75', 'DK697', 'Kangdaok' and 'Kwangpyongok' hybrids had good growth characters and forage productivity at poorly drained paddy field and dry matter yield at poorly drained paddy field was 65.6% level compared with well drained paddy field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.241-248
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• 2017

Yield of potato is largely influenced by drought stress. This study was conducted in Gangneung and Cheongju during the spring cropping of potato. Potatoes in the Gangneung area were affected by drought but there was no damage due to drought in Cheongju. During the early-growth stage, the contents of inorganic components like available phosphate and growth characteristics of the potato leaf in Cheongju were significantly higher than those in Gangneung but there was no difference after the flowering stage. It was considered that the potato plants cultivated in Cheongju could vigorously grow than that of Gangneung under drought stress. In addition, the content of calcium (Ca), which is a secondary messenger related to aging, was found to be higher in potato plants grown in Cheongju than in Gangneung and accumulated more quickly in potato plants of Cheongju. Because magnesium (Mg) was also found to be higher in potato plants from Gangneung by a wide margin, this phenomenon was thought be related with drought stress. The amounts of all inorganic components absorbed from soil were higher in Cheongju than in Gangneung, showing a relatively higher plant biomass in Cheongju. Correlations of development indexes related to leaf showed less or no relation in Gangneung. According to yield characteristics of the harvest stage, although yield was greatly reduced under drought stress condition, the rate of commercial yield was not significantly affected under the drought stress condition. Consequently, it was considered that these responses to drought stress could be utilized to stabilize potato production under the stressful conditions associated with abnormal climate.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.2
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• pp.119-126
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• 2011

This experiment was carried out to know adaptability and forage production and quality of sorghum, sorghum ${\times}$ sudangrass and sudangrass hybrids depend on drained condition at paddy field from 2007 to 2008 at Chungnam province. Growth, forage production and quality of sorghum, sorghum ${\times}$ sudangrass and sudangrass hybrids showed more well drained condition than poorly drained condition at paddy field. Among growth characteristics, 'SS405' hybrids were somewhat strong for waterlogging, then and good at stem diameter, disease resistance. The dry yield of 'SS405' hybrid at poorly drained paddy field was the highest as 12,938 kg per ha. Fresh yield of poorly drained paddy field was 52.7% compared to that of well drained paddy field. The dry matter yield of poorly drained paddy field was the lower as 66.4% than that of well drained condition. ADF (acid detergent fiber), NDF (neutral detergent fiber), CP (crude protein) and IVDMD (in vitro dry matter digestibility) in poorly drained paddy field were 90.3%, 100.6%, 85.7% and 89.6% level compared to well drained paddy field.

• KSBB Journal
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• v.17 no.1
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• pp.93-99
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• 2002

Two-stage fed-batch culture of Candide tropicalis that was designated primarily to cultivate the cell in the glucose medium (1st stage) and then produced the xylitol from xylose medium (2nd stage) was developed to improve a xylitol yield and productivity. In the growth stage, glucose was automatically supplied to the fermentor by pH-stat mode when the pH was up 5.7, When a feeding medium was added in order to reach the glucose and yeast extract concentrations up to 100 and 40 g/L, respectively, a high cell concentration and a relatively low ethanol concentration were obtained in 18.5 h culture. In the production stage, initial xylose concentration of 150 g/L was the most favorable for obtaining the final xylitol concentration and productivity. The addition of mineral salts was also enhanced a xylitol production. But the aeration rate was not significantly affected a xylitol production. When the addition of 16 g yeast extract and 232.5 g xylose powder at the production stage was used, xylitol yield and productivity were significantly increased. With these conditions, xylitol concentration, yield and productivity of 108.9 g/L, 74%) and 3.3 g/L·h, respectively, were obtained in a final volume of 1.58 L. The further addition of 16 g yeast extract and 232.5 g xylose powder increased the working volume partly (1.67 L) and resulted in a relatively high xylitol concentration, yield and productivity of 193 g/L, 70% and 3.6 g/L·h, respectively.

• Food Science and Preservation
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• v.14 no.6
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• pp.702-708
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• 2007

The effects of pectinase treatment and other processing conditions on juice yield from Rubus coreanus, and physicochemical changes during alcohol fermentation, were investigated. The yield from R. coreanus increased by 8.60% with Pectinex 100L treatment (500 ppm, 30 min) compared to a control group. The soluble solid content in the group fermented at $24^{\circ}Brix$ by addition of sucrose (24B-group), and the group fermented at $8^{\circ}Brix$ by addition of 16% sucrose after 4 days of fermentation (8B-group) decreased to $8.2{\sim}8.3$ and $7.7{\sim}8.0%$ after 10 days of fermentation, respectively, and no significant differences were observed with Pectinex 100L treatment. Initial titratable acidity in the enzyme treatment was slightly higher ($1.18{\sim}1.22%$) than for the control group (1.02%). The initial $L^*$ and $b^*$ values of R. coreanus juice decreased with enzyme treatment, and the $a^*$ value increased, but the color difference (${\Delta}E$) between the control and enzyme treatment gradually decreased with fermentation time. The ethanol contents in the 24B-group and the 8B-group were $16.01{\sim}16.22%$ and $13.29{\sim}13.52%$, respectively, after 10 days of fermentation. The methanol contents in the enzyme treatment and the control were $0.359{\sim}0.404$ and $0.520{\sim}0.604$ mg/mL, respectively, and within standard regulations (1 mg/mL).

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.319-325
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• 1985

Agar was prepared from domestic agarophyte (Gelidium amansii) by a process of acid extraction. Optimal conditions in the acid treatment of the seaweed and the gelling properties of the agar thus prepared were investigated. The yield and gel strength of the control (the agar extracted with distilled water) showed 13,3% and 306g/$cm^2$, respectively. The yield of 38.7% was obtained when agar was extracted with 0.007N Hydorchloric acid while the gel strength of agar,511g/$cm^2$ was observed with the agar extracted with 0.005N Hydorchloric acid solution. The agar extracted with hydrochloric acid solution showed excellent properties of agar at the acid concentration range 0.005N-0.01N The cooking time of 60 min. was found to be effective to the yield and also to the gelling property of the agar and the cooking longer than 60 min. was proved to be destructive to agar. In general, yield and gelling properties of the agar obtained showed a close relation to the acid concentration and cooking time, but no consistent influence on the contents of ash and sulfur trioxide.

• Journal of the Korean GEO-environmental Society
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• v.11 no.2
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• pp.33-42
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• 2010

The main objective of this study was to offer informations about the current conditions of stream sediments and to evaluate biochemical methane potentials of stream sediments from the urban streams in Busan city using conventional BMP tests. First we select total 5 urban streams and collect sediment samples. Then, COD, proximate analysis, volatile solid, organic carbon content and elemental analysis were conducted to determine characteristics of the sediments. Results show that COD, volatile solid and organic carbon content are determined in the range of $15.20{\sim}75.07mg\;g^{-1}$, 2.34~11.54% and 1.28~34.21%, respectively. Also, several biochemical methane potential tests were performed in a laboratory. As a result, pH values of the reactors generally increased and then stabilized at 7.11~7.35. In addition, C/N ratio, ultimate methane and carbon dioxide yield (mL/g VS) and biodegradability (%) were determined to 1.05~10.27, 10.1~179.4, 10.3~34.4 and 4.0~30.1, respectively. For the determination of the correlations between ultimate methane yield and ultimate carbon dioxide yield, C/N ratio, COD, volatile solid and organic carbon content, a linear model was fitted to the data using a least-squares algorithm. As a result, except for COD ($r^2=0.7586$) and volatile solid ($r^2=0.7876$), Linear model was well fitted to each data with good values of the correlation coefficient ($r^2=0.9795{\sim}0.9858$). Finally, we propose empirical equations, which contain C/N ratio or TOC, for the prediction of ultimate methane yield for the urban streams in Busan city.

• Advances in Energy Research
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• v.1 no.2
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• pp.147-163
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• 2013

The world faces several issues of energy crisis and environmental deterioration due to over-dependence on single source of which is fossil fuel. Though, fuel is needed as ingredients for industrial development and growth of any country, however the fossil fuel which is a major source of energy for this purpose has always been terrifying thus the need for alternative and renewable energy sources. The search for alternative energy sources resulted into the acceptance of a biofuel as a reliable alternative energy source. This work presents the study of optimization of process of transesterification of vegetable oil to biodiesel using NaOH as catalyst. A $2^4$ factorial design method was employed to investigate the influence of ratio of oil to methanol, temperature, NaOH concentration, and transesterification time on the yield of biodiesel from vegetable oil. Low and high levels of the key factors considered were 4:1 and 6:1 mole ratio, 30 and $60^{\circ}C$ temperatures, 0.5 and 1.0 wt% catalyst concentration, and 30 and 60 min reaction time. Results obtained revealed that oil to methanol molar ratio of 6:1, tranesetrification temperature of $60^{\circ}C$, catalyst concentration of 1.0wt % and reaction time of 30 min are the best operating conditions for the optimum yield of biofuel from vegetable oil, with optimum yield of 95.8%. Results obtained on the characterizzation of the produced biodiesel indicate that the specific gravity, cloud point, flash point, sulphur content, viscosity, diesel index, centane number, acid value, free glycerine, total glycerine and total recovery are 0.8899, 4, 13, 0.0087%, 4.83, 25, 54.6. 0.228mgKOH/g, 0.018, 0.23% and 96% respectively. Results also indicate that the qualities of the biodiesel tested for are in conformity with the set standard. A model equation was developed based on the results obtained using a statistical tool. Analysis of variance (ANOVA) of data shows that mole ratio of ground nut oil to methanol and transesterification time have the most pronounced effect on the biodiesel yield with contributions of 55.06% and 9.22% respectively. It can be inferred from the results various conducted that vegetable oil locally produced from groundnut oil can be utilized as a feedstock for biodiesel production.