• Korean Journal of Environmental Agriculture
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• v.34 no.1
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• pp.38-45
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• 2015

BACKGROUND: For commercial production of greenhouse crops under shorter day length condition, supplementary radiation has been usually achieved by the artificial light source with higher electric consumption such as high-pressure sodium, metal halide, or incandescent lamps. Light-Emitting Diodes (LEDs) with several characteristics, however, have been considered as a novel light source for plant production. Effects of supplementary lighting provided by the artificial light sources on growth of Kale seedlings during shorter day length were discussed in this experiment. METHODS AND RESULTS: Kale seedlings were grown under greenhouse under the three wave lamps (3 W), sodium lamps (Na), and red LEDs (peak at 630 nm) during six months, and leaf growth was observed at intervals of about 30 days after light exposure for 6 hours per day at sunrise and sunset. Photosynthetic photon flux (PPF) of supplementary red LEDs on the plant canopy was maintained at 0.1 (RL), 0.6 (RM), and $1.2(RH){\mu}mol/m^2/s$ PPF. PPF in 3 W and Na treatments was measured at $12{\mu}mol/m^2/s$. Natural light (NL) was considered as a control. Leaf fresh weight of the seedlings was more than 100% increased under the 3 W, Na and RH treatment compared to natural light considering as a conventional condition. Sugar synthesis in Kale leaves was significantly promoted by the RM or RH treatment. Leaf yield per $3.3m^2$ exposed by red LEDs of $1.2{\mu}mol/m^2/s$ PPF was 9% and 16% greater than in 3W or Na with a higher PPF, respectively. CONCLUSION: Growth of the leafy Kale seedlings were significantly affected by the supplementary radiation provided by three wave lamp, sodium lamp, and red LEDs with different light intensities during the shorter day length under greenhouse conditions. From this study, it was suggested that the leaf growth and secondary metabolism of Kale seedlings can be controlled by supplementary radiation using red LEDs of $1.2{\mu}mol/m^2/s$ PPF as well as three wave or sodium lamps in the experiment.

• The Journal of Korean Philosophical History
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• no.32
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• pp.79-112
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• 2011

Since Noron(老論) had organized in the period of Sookjong(肅宗), it constantly had led the political situation of Choson until Choson(朝鮮) perished as the grasping political power. Studies and thoughts development of Noron can be devided into four periods. First, the term of politics of faction of the period of Sookjong. Second, a period of Youngjo(英祖) and Joungjo(正祖). Third, a period of politics of power(勢道政治). Fourth, the latter term of 19century. We can look into an origin and development aspect in outline by dividing like this. The general character of Noron can be summarized by the respect of Song Si-yeol(宋時烈, 1607-1689), the theory of a party of a man of virtue(君子黨論) based on the theory of moral civilization of Choson(朝鮮中華論), the succession of Lee i(李珥; 1636-1684)'s neo-confucianism, rejecting all teaching that does not conform to neoconfucianism and protecting right studies, and oppression of Roman Catholic. The noticeable scholars of Noron were Kwon sang Ha(權尙夏; 1641~1721), Kim chang hyup(金昌協; 1651~1708), Lee jea(李縡; 1680~1746) etc. These scholars of Noron following Song Si-yeol had tried to raise "Learning of the Way"(正明道) by respecting Zushi and removing injustice(尊朱子攘夷狄), also believed people should embody moral values in their society and country. and possessed an will guiding to stabilize the country by rejecting uncivilization(尊王攘夷). Above all, they insisted, the King of Choson should rule with 'lighting heavenly reason'(明天理). Also they insisted the King and countrymen should together strive to recover civilization of moral humanity and destroy uncivilzation. But gradually they lost the motive and purpose of moral politics in the seventeenth century. Finally Noron Byeokpa(?派) take over the reins of government. It resulted in the bad effect of politics of autocrat(勢道政治) having their own way to use power of authority after death of Jungjo(正祖). The peculiar character of Noron politics can valued as the extreme aspect of 'according of politics and scholarship'(政學一致).

• Korean Journal of Poultry Science
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• v.49 no.3
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• pp.139-144
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• 2022

This study was conducted to investigate the effect of three different photoperiods on growth performance, blood properties, and stress indicators in broiler chicks between 1-7 days after hatching. Two hundred and fifty-two 1-day-old male broiler chicks (57.0±0.12 g) were divided into three treatments, with 4 replicates per treatment and 22 birds per replicate subjected to three different photoperiods of 24L, 22L/2D and 18L/6D. A light-emitting diode bulb served as the light source, with an illuminance of 30 lx. As an experimental diet, a commercial feed based on a corn-soybean meal, with 22% CP and 3,150 kcal/kg ME diet, and water were fed ad libitum. Body weight gain, feed conversion ratio, and liver weight ratio showed a statistically significant difference between the 18L/6D and 24L treatments (P<0.05), but with no significant difference between the 22L/2D treatment and either the 24L or 18L/6D treatment. The breast meat ratio was 5.59% in the 18L/6D treatment group, which was lower than that of other treatment groups (P<0.05). The triglyceride levels were highest (P<0.05) in the 18L/6D treatment among treatments, but alanine aminotransferase levels were significantly higher (P<0.05) in the 22L/2D treatment than in the 24L treatment. Levels of cytokines, i.e., Interleukin-6 and Tumor Necrosis Factor-α did not show a significant difference among the treatments, but corticosterone content was significantly higher (P<0.05) in the 24L treatment than in the 18L/6D treatment. In conclusion, 22 hours of lighting is appropriate between 1~7 days after hatching, considering growth performance and the overall health of broiler chicks.