• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.320-320
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• 2017

Recently, the rice growing time was extended by the global warming. This study was conducted to investigate the possibility of rice double cropping system in southern Korea. The first transplanting was with six cultivars ('Kilala397', 'Baekilmi', 'Joun', 'Hanseol' and 'Jungmo1031') on April 15. All cultivars could be harvested at the end of July. Adaptable cultivars for the first cultivation were 'Kilala397', Baekilmi' and 'Joun'. The rice yields at the first cultivation was about 95% of local average yield. Although the yield was slightly less, the first cultivation was considered to have economic benefits, because of the high market price of rice. In the second transplanting was with five cultivars ('Manjong', 'Joun', 'Deabo', 'Jinok' and 'Kilala397') on April 15. All cultivars could be harvested in early November. Adaptable cultivars for the second cultivation were 'Jinok' and 'Kilala397'. The rice yields at the second cultivation was about below the 60% of local average yield, because there was the less growth than normal season cultivation. Consequently, southern Korea' annual rice double cropping system is considered to have no economic value yet. However, the research should be continued considering the temperature rise of global warming.

• The Mathematical Education
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• v.22 no.3
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• pp.43-47
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• 1984

• Macromolecular Research
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• v.17 no.1
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• pp.67-67
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• 2009

• Journal of the Korean Society for Precision Engineering
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• v.22 no.1
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• pp.47-52
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• 2005

In this paper, the effect of TiN-coating on product quality such as dimensional accuracy and surface roughness is experimentally investigated. A punch of SKD11 material in cold forging an automotive bearing shaft and its related process found in a cold forging company are selected as the test example. The effect of TiN-coating is revealed in a quantitative manner. It is to be noted that TiN-coating is effective in controlling the dimensional accuracy and surface roughness as well as in increasing tool lift.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.143-147
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• 2004

In this paper, effect of TiN-coating on product quality such as dimensional accuracy and surface roughness is experimentally investigated. A punch of SKD11 material in cold forging of an automotive bearing shaft and its related process found in a cold forging company ate selected as the test example. The effect of TiN-coating is revealed in a quantitative manner. It is to be noted that TiN-coating is effective in controlling the dimensional accuracy and surface roughness as well as in increasing tool lift.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.158-161
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• 2005

In this paper, the precision electric discharge machining technology, the powder electric discharge machining technology, is applied to making a cold forging die for making the helical type of clutch gear. Various working conditions are investigated with emphasis on reduction of the electrode wear and enhancement of the surface roughness. Through the research work, the key technology of making the helical gear forging dies is achieved.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.274-283
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• 2020

Seed dormancy is an adaptive trait in which seeds do not germinate under unfavorable environmental conditions. Low dormancy seeds are easily germinated under optimal environmental conditions, and these characteristics greatly reduce the yield and quality of crops. In the present study, we compared the pre-harvest sprouting (PHS) rate of two cultivars, Joun and Jopyeong, using the Winkler scale after heading day and temperature of the test. The PHS rate increased as the Winkler scale after heading day increased from 700℃ to 1100℃ and the temperature of the test increased. In all conditions, the PHS rate of Jopyeong was higher than that of Joun. RNA-sequencing was used to analyze the cause of the high PHS rate. We analyzed the biological metabolic processes related to the abscisic acid (ABA) metabolite pathway using the KEGG mapper with selected differentially expressed genes in PHS seeds. We found that the expression of ABA biosynthesis genes (OsNCEDs) was down-regulated and that ABA catabolic genes (OsCYP707As) was up-regulated in PHS seeds. However, the quantitative real-time PCR results showed that Joun had a higher expression of OsNCEDs than that of Jopyeong, but OsCYP707As did not yield a significant result. Joun displayed higher ABA content than that of Jopyeong not only during ripeness time but also during PHS treatment. Taken together, we provided evidence that the ABA content remaining in the seed is important to the PHS rate, which is determined by the expression level of the ABA biosynthesis gene OsNCEDs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.397-398
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.365-366
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.209-210
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• 2007