• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.145-154
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• 2013

Recently, damage occurrence by wind erosion has been increasing in society. In times past, such problems only took place in desert area ; however, in recent years, the wind erosion problem is spreading out to agricultural land. Wind erosion in agricultural land can cause loss of loam soils, the disturbance of the photosynthesis of the crop fields and serious economic losses. To overcome the mentioned problems, installation of windbreak fence can be recommended which function as disturbing strong wind and wind erosion. However, there is still no proper guideline to install the windbreak fence and the installation used to rely on the intuition of the workers due to the lack of related studies. Therefore, this study measured the aerodynamic resistance of screens of the windbreak fence using the apparatus for testing screens. The apparatus for testing screens was designed to measure pressure loss around the screen. Measured pressure loss by wall friction compensated for pressure loss to calculate the aerodynamic resistance of screens. The result of pressure loss by regression analysis derived the aerodynamic coefficient of Darcy-Forchheimer equation and power law equation. The aerodynamic resistance was constant regardless of the overlapped shape when the screen was overlapped into several layers. Increasing the number of layers of the screen, internal resistance increased significantly more, and pressure loss caused by the screen also increased linearly when the wind speed was certain conditions, but permeability had no tendency. In the future, the results of this study will be applied to the computational fluid dynamics simulation. The simulation models will be also validated in advance by wind tunnel experiments. It will provide standard of a design for constructing windbreak fence.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.664-668
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• 2009

"Boram" is a new $F_1$ hybrid of rapeseed (Brassica napus L.) with early maturing, high yield and high oleic acid. This cultivar was developed from the cross between Mokpo-CGMS (male steile line) and 8634-B-1-3-1-8 (restore line) for the production of edible oil and biodiesel in 2006. Yield trials were conducted from 2007 to 2008 and regional adaptation trials were examined at four locations in 2008. "Boram" has green and parted leaf, yellowish flower, and black seed coat. The ripening period of "Boram" is similar to "Sunmang", but 3 days faster than "Tammiyuchae". The average seed yield of the regional adaptation trials was 424 kg/10a, which was 11 and 48% higher than "Sunmang" and "Tammiyuchae" variety. Total oil content of "Boram" was 44.2%. In fatty acid composition, "Boram" has no erucic acid. However, oleic acid content is 68.5%, which is 3.7 and 5.4% higher than "Tammiyuchae" and "Sunmang". And total glucosinolate content was 2.27mg/g. Therefore this variety is recommended as a leading variety at southwestern areas including Jeonnam, Jeonbuk and Kyeongnam provinces and Jeju island of Korea.

• Korean Journal of Medicinal Crop Science
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• v.16 no.5
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• pp.356-370
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• 2008

This study was conducted for screening on antioxidant activity of 429 plants and selecting new potential antioxidant candidates. In vitro test models such as scavenging activity on DPPH radical and inhibitory activity on linoleic acid oxidation were used in the preliminary study. Flower of Sanguisorba officinalis, flower of Sedum kamtschaticum, flower of Rumex obtusifolius, and root of Sedum kamtschaticum showed very effective antioxidant activity on DPPH radical and linoleic acid oxidation. Those plants showed 8.1, 9.4, 9.9, $11{\mu}g/ml$ in DPPH radical scavenging activity as $SC_{50}$ and did 80.4, 80.1, 84.5, 88.0% in inhibition activity on linoleic acid oxidation, respectively. Root of Sedum middendorfianum M. showed positive effects in superoxide radical scavenging activity ($38.4{\mu}g/ml$) and inhibitory effect on $CuSO_4$-induced LDL oxidation (53.8% at final concentration of $1{\mu}g/ml$). Gleditsia japonica Mig. showed high antioxidant activity on LDL oxidation as 71.6% at final concentration of $1{\mu}g/ml$ and total phenol content of 958.5 mg% as tannic acid equivalent. In conclusion, we think that these plants having potent antioxidant activity might be studied further and could be used as new resources for many purposes including healthy food, functional cosmetics and drug development etc.