• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.142-145
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• 1998

The experiment was conducted to elucidate the optimum planting data and fertilization level of Aruncus dioicus var. kamtscacus HARA. Plant height was increased as the seeding date was delayed. There was no transparent difference on plant height indifferent fertilization level. Nuber of stems was remarkably increased in the fertilization 14-14-12kg. Fresh leaf yield in the fertilization of 24-18-15kg was incresed about 31% comparing in the fertilization of 14-14-12kg. As a result, the optimum planing date and fertilization level was Jan. 15 and 24-18-15kg per 10a, respectively.

• Plant Resources
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• v.7 no.3
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• pp.181-186
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• 2004

To find out the optimum fertilizer level for high yielding variety, Paldanghomil, experiment was conducted with 15 compositions of fertilizer levels at the experiment field of forage rye in Sunchon National University from Sep. 1998 to Aug. 1999. The effects of nitrogen fertilizer on plant growth were large significant but increasing rate of application in potassium and phosphate fertilizers above 10kg/10a had negligible effects on plant growth. Raising nitrogen application rate of fertilizers turned out to be 18-10-10kg/l0a of N-P$_2$O$_{5}$-K$_2$O. Content of crude protein was the highest and that of crude fiber such as NDF, ADF, cellulose and lignin were lowest at this rate. Furthermore, IVDMD was high and dry matter yield were the highest at the optimum rate.e.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.12-18
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• 2006

The transesterification of vegetable oils into Biodiesel at $60^{\circ}C$ was performed on the rotary viscometer. The overall yield(%) of fatty acid methyl ester from canola oil at optimum conditions was 95%. The viscosities of fatty acid methyl esters were predicted by Orrick and Erbarr's model. The overall yield increased as the viscosities of fatty acid methyl esters decreased. The limiting molar ratio of methanol to oil appeared to be 1:5. The content of sodium hydroxide as the optimum catalyst appeared to be 0.5wt%.

• Food Science and Preservation
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• v.3 no.2
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• pp.171-178
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• 1996

This study was carried out for the purpose of improving the persimmon vinegar. The acetic acid bacteria strain JST-3, using acetic acid fermentation was isolated from the traditional persimmon vinegar. The optimum conditions for high yield of acetic acid were studied in the shaking bath. Acetic acid bacteria was cultured at 3$0^{\circ}C$ for 4 days and transferred to persimmon alcoholic juice for acetic acid fermentation. The optimum initial acidity for acetic acrid fermentation was 1%(w/v) and the addition of glucose or yeast extract was observed to produce relatively low yield of acetic acid. Succinic and acetic acid were major organic acid in the persimmon vinegar, The contents of lactic acid which was known to increase off-flavor were very low. Sensory evaluation revealed that the persimmon vinegar prepared in this study was superior to two commercial ones in the aroma and taste.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.52-57
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• 2006

This research was carried out to determine the effect of controlling nitrogen application on tiller development, yield, and quality of rice under scanty or excess seedling stands in direct-seeded rice on flooded soil surface. Seedling stand was set to 3 levels: scanty $(60/m^2)$, optimum $(120/m^2)$, and excess $(200/m^2)$. In the scanty plot, additional 4 kg/10a nitrogen was applied at the 3rd leaf stage to promote tiller development. On the other hand, applying 3.3 kg/10a nitrogen at 5th leaf stage in the excess plot was omitted to suppress tillering. Maximum numbers of tillers per plant were 15.2 and 8.6 in scanty and excess plots, respectively, as compared with 9.8 in optimum plot. Productive tiller rate decreased with the increase in number of seedling stands. Regardless of seedling density, the first tiller developed on the 3rd node of rice stem from the bottom. The primary tillers developed at 3, 4, 5, 6, 7 nodes in scanty plot, 3, 4, 5 nodes in optimum plot, and 3, 4 nodes in excess plot. The secondary tillers developed only in some portion of plants in scanty and optimum plots. The order of tiller emergence was negatively correlated to stem length, panicle length, non-productive tiller number, grain number per panicle, and fertility in scanty plot, and to perfect grain ratio in excess plot. In the optimum plot, however, the order of tiller emergence was not correlated to any of the mentioned characteristics. The perfect grain ratio of scanty plot was the highest because green-kerneled rice was a very small portion in the primary tillers as compared with those of optimum and excess plots. Yield indexes of scanty and excess plots were 99%, and 97%, respectively, of the yield (494 kg/10a) in optimum plot. In conclusion, when seedling stands are not at optimum level, rice yield and quality similar to optimum planting density level can be obtained by means of controlling nitrogen application.

• Journal of Animal Science and Technology
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• v.60 no.2
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• pp.1.1-1.6
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• 2018

Background: Maize fodder is being used as staple feed for livestock but it lacks protein and essential amino acids; lysine and tryptophan. Intercropping maize with leguminous soybean crop is promising technique under limited land resources of South Korea but it can only give considerable advantages when adequate distance is provided between corn and soybean rows. Main aim of present study was to find-out adequate distance between corn and soybean seeding rows for optimum growth, yield and nutritive value of intercropped forage. Methods: Different interrow distances between corn and soybean were evaluated under four treatments, viz. 1) Corn sole as positive control treatment 2) Zero cm between corn and soybean (control); 2) Five cm between corn and soybean; 3) 10 cm between corn and soybean, with three replicates under randomized block design. Results: Findings depicted that height and number of corn stalks and ears were similar (P > 0.05) among different treatments. Numerically average corn ear height was decreased at zero cm distance. Dry matter percentage in all components; corn stalk, corn ear and soybean was also found not different (P > 0.05) but dry matter yield in component of corn ear was lower (P < 0.05) at zero cm distance as compared to that of 5 and 10 cm interrow distances. In case of nutritive value, total digestible nutrient yield in intercropped corn was also found lower (P < 0.05) at zero cm distance than that of 5 and 10 cm interrow distances between corn and soybean seeding rows. Substantial decrease in dry matter yield of maize ear at zero cm distance might be attributed to factor of closed interrow spacing which made interplant competition more intensified for light interception, necessary for photosynthetic activity. Lower dry matter yield in ear also reduced total digestible nutrients in intercropped maize because it was determining factor in calculation of digestible nutrients. The optimum yield and nutritive value of forage at wider interrow distance i.e. 5 cm between corn and soybean might be due to adequate interseed distance. Conclusion: Conclusively, pattern of corn and soybean seeding in rows at 5 cm distance was found suitable which provided adequate interrow distance to maintain enough mutual cooperation and decreased competition between both species for optimum production performance and nutritive value of intercropped forage.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1116-1123
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• 2020

Velvet antler (VA) is a historically traditional medicinal supplement and is well known in Asian countries for its pharmaceutical and health benefits. The objectives for this study were to optimize the hot water extraction (HWE) of VA for the Korean VA industry, and to determine the most effective pretreatment method among microwave (MW), ultrasonication (US), and enzymatic (EZ) techniques. Using response surface methodology, optimum extraction temperatures and times were determined by central composite design configuration based on extraction yield and sialic acid content. Various quality parameters of VA extract including yield, soluble solid, protein, and sialic acid contents were also compared with the conjunction of HWE and pretreatment. The yield and sialic acid content of VA extract were determined to be 40% and 0.73 mg/g, respectively, under an optimum temperature of 100℃ at 24 h of extraction time. The yields from VA extracts pretreated with MW, US, and EZ were 17.42%, 19.73%, and 29.15%, respectively. Among the tested commercial enzymes, pepsin was the most effective proteolytic enzyme and led to the highest yield (47.65%), soluble solids (4.03 °brix), protein (1.12 mg/ml), and sialic acid (3.04 mg/ml) contents from VA extract.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.6
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• pp.769-775
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• 2008

This study was on the relative net income (RNI) for 18,286 Iranian Holstein cows from 799 herds, with first freshening between 1991 and 2000. Two kinds of production system, which differed mainly in milk pricing system and feed cost, were considered. Four different models adopted from the literature were examined to find the optimum model. They differed by the cost of rearing and growth after first calving and they needed different amounts of economic data at the farm level. Results showed that four measures of RNI were highly correlated (>0.96) and could be used equally to measure lifetime profitability of cows. Therefore, in herds without a regular system for recording economic and management data, use of the simplest model is recommended. Multiple regression analysis revealed that RNI was affected by age at first freshening, milk yield and days of productive life (DPL), regardless of production system, and a similar breeding goal could be defined for the two systems. Multiple regression analysis of RNI showed that in order to obtain an unbiased estimate of economic value for DPL, the per day milk yield, not total lifetime milk yield, should be included in the regression model along with DPL. Regression analysis suggested that it is possible to predict RNI using information on age at first freshening along with the length of first lactation and per day milk yield with a coefficient of determination ranging from 0.44 to 0.47.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.405-411
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• 1994

This study was carried out to determined the optimum seeding rate and number of seedling stands per unit area for high yield with two varieties of rice, Nakdongbyeo (Japonica type) and Samgangbyeo (Indica x Japonica type), in direct water-seeded rice culture at Crop Experiment Station. Seeds coated with $CaO_2$ after germination were sowed at May 4 in 7 levels, such as 1.6, 1.8, 2.1, 2.7, 3.5, 4.0, 4.3kg /10a, and the number of seedling stands per square meter was adjusted to be 30, 40, 60, 80, 100, 120, 140 plants, respectively. The maximum number of tillers increased as the seeding rates increased, but the ratio of effective tillers decreased. The critical dates of effective tillering of tested varieties were delayed by the lower seeding rates, and the date was June 18 at the plot of seeding rate with 3.5kg /10a. The number of panicles per unit area increased in accordance with the increased seeding rates. The number of spikelets per panicle in Nakdongbyeo was not affected by the seeding rates, but in Samgangbyeo it decreased as the seeding rate increased. The optimum number of seedling stand per square meter appeared to be 78 in Nakdongbyeo and 120 in Samgangbyeo, respectively. It meant that the optimum seeding rates for Nakdongbyeo and Samgangbyeo were about 2.7 and 4.0kg /10a, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.179-184
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• 2004

In this work, a copper-clad aluminum composite was fabricated using hot hydrostatic extrusion with various extrusion ratios (8.5, 19, 49) and semi-die angles (30, 45, 60 degree) at a temperature of 32$0^{\circ}C$, Material characteristics of copper-clad aluminum composites were determined from compression tests and hardness tests The results showed that for ER of 8.5, the optimum semi-die angle was below or equal to 30 degree and a pressure drop was about 31%. For ER of 19, the optimum semi-die angle was in the range of 40 to 50 degree and a pressure drop was about 38%. In the case of ER=49, the optimum semi-die angle was above or equal to 60 degree and a pressure drop was about 36%. Compressive yield strength was maximum for ER of 8.5 and semi-die angle of 30 degree and the value of maximum was 155 MPa. Uniform hardness distribution was obtained as the extrusion ratio increases and the semi-die angle decreases. In the case of ER=8.5 and semi-die angle of 30 degree, the lowest extrusion pressure and the maximum compressive yield strength was obtained. Therefor, it was concluded that the optimum extrusion condition for fabricated copper-clad aluminum composites under hydrostatic pressure environment was ER of 19 and semi-die angle of 30 degree.