• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.214-219
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• 2013

This study was conducted to examine the effect of LED light quality and treatment time on the growth and flowering in potted plants of Impatiens (Impatiens hawkerihybrid). Plant height of Impatiens was enhanced under Blue light, regardless of treatment time. Root length and stem diameter of Impatiens were enhanced by Red light or Blue light. The number of internodes was not influenced by LED light quality. The number of branches of Impatiens was increased under Blue light, but treatment time did not result in statistically significant differences. Leaf area was increased by all LED lights in Impatiens. The number of flower buds and open flowers was decreased by LED light, but days to flowering were reduced by Red light in Impatiens. Chlorophyll and anthocyanin content were not significantly affected by LED light, but anthocyanin content tended to increase by Blue light for 4 h after sunset. Fresh and dry weights were enhanced by Blue light in Impatiens.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.45-53
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• 2003

The object of this study was to develop the control technology of daily integral photosynthetic photon flux (PPF) by the artificial lighting and shading screen in greenhouse. The shading time needed to get the target PPF by using two types of shading screens having shading ratio of 55% and 85% was analyzed. The results showed the shading ratio of screen to be installed in greenhouse should be different depending on the amount of target PPF to be controlled. The PPF control experiment by using the 55% shading screen in July and August showed that the maximum difference between measured and calculated value was about 5 mol$.$ $m^{-2}$ $.$ $d^{-1}$ in no shading condition. This difference is satisfactory result because the daily integral PPF is quite different depending on the weather condition. The simulation result about PPF distribution pattern shortened the time needed to find the proper arrangement of artificial lightings in greenhouse. But the further study was required to find the supplemental lighting arrangement to be able to provide the exactly uniform distribution of target light intensity. The supplemental irradiation time needed to acquire the target daily integral PPF for different supplemental light intensities, weather conditions, and months was analyzed. The result showed that the supplemental light intensity should be decided depending on the amount of target PPF to be controlled. The result of PPF control experiment conducted by using 55% shading screen and 300 $\mu$mol$.$ $m^{-2}$ $.$ $s^{-1}$ supplemental light intensity from the end of May to the beginning of June showed that the maximum difference between target and measured value was about 3 mol$.$ $d^{-1}$ $.$ $m^{-2}$ . If we consider that the difference of the daily integral PPF depending on weather condition was the maximum 30 mol$.$ $m^{-2}$ $.$ $d^{-l}$, the control effect was acceptable. Although the result of this study was the PPF control technology to grow lettuce, the data and control method obtained could be employed for other crop production.n.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.48-56
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• 2023

High-pressure sodium (HPS) lamps have been widely used as a useful supplemental light source to emit sufficient photosynthetically active radiation and provide a radiant heat, which contribute the heat requirement in greenhouses. The objective of this study to analyze the thermal characteristics of HPS lamp and thermal behavior in supplemented greenhouse, and evaluate the performance of a horizontal leaf temperature of sweet pepper plants using computational fluid dynamics (CFD) simulation. We simulated horizontal leaf temperature on upper canopy according to three growth stage scenarios, which represented 1.0, 1.6, and 2.2 plant height, respectively. We also measured vertical leaf and air temperature accompanied by heat generation of HPS lamps. There was large leaf to air temperature differential due to non-uniformity in temperature. In our numerical calculation, thermal energy of HPS lamps contributed of 50.1% the total heat requirement on Dec. 2022. The CFD model was validated by comparing measured and simulated data at the same operating condition. Mean absolute error and root mean square error were below 0.5, which means the CFD simulation values were highly accurate. Our result about vertical leaf and air temperature can be used in decision making for efficient thermal energy management and crop growth.

• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.135-141
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• 1992

Effects of various artificial light sources on the growth of Chinese white cabbage, Chinese flat cabbage, lettuce, garland chrysanthemum, and green perilla were investigated. Plants were grown under different treatments for three weeks. Generally, the growth of artificial light treatment were better than natural daylight(ND). The greatest growth and external quality occurred in high-pressure sodium lamp(HPS). In incandescent lamp(IL), fresh weight was heavy, but marketable quality was poor because of succulent(or spindly) growth. Overall, vitamin C content were no difference among treatments. But relative chlorophyll content was somewhat high in HPS.

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.455-463
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• 1996

Studies were carried out to determine the effect of sulfur dioxide on leaf injury and yield of ten soybean cultivars. Plants were fumigated with 2.0 ppm of $SO_2$ for 4 or 8 h in a closed-top field chamber. In the comparison of foliar injury, Paldalkong and Eunhakong were more susceptible to $SO_2$ than Bogwangkong, Jangsukong, and Jangkeungkong. Correlations between chlorophyll contents, peroxidase activity, and stomatal resistance of leaves and foliar susceptibility were insignificant. However, significant correlations $(r=-0.611^{\ast})$ were found between superoxide dismutase activity and foliar injury rates. Dry weight, number of pods and total grains were significantly reduced by $SO_2$ fumigation but plant height, number of nods and weight of 100 grains were not affected. Yield reduction rates were higher in Eunhakong and Paldalkong than in Bogwangkong and Jangkeungkong. A liniar relationship was found between foliar injury rate and the percent crop loss with a significant coefficient of b=-1.17 in the susceptible cultivar of Paldalkong, but Bogwangkong, insusceptible cultivar, showed lower value of -0.165.

• Korean Journal of Environmental Agriculture
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• v.38 no.1
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• pp.61-67
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• 2019

BACKGROUND: Many studies on artificial lighting have been recently performed to investigate its effect on agricultural products with good quality. This review was aimed at comparing the effects of artificial light on functional metabolites of the plants that were grown in greenhouses and growth chamber. METHODS AND RESULTS: It has been summarized that artificial lighting both in growth chambers and greenhouses caused different functional metabolites patterns depending on light quality. Even though the same light quality was applied, different patterns in metabolites were observed in different plant species. For the same species, supplementation of the same light quality in both growth chambers and greenhouses did cause different functional metabolites patterns. CONCLUSION: Artificial lighting caused different patterns in functional metabolites of plants grown in greenhouses and growth chambers, depending on the light quality and/or plant species. The manipulation of plant growth and functional metabolites would be possible by engineering the light qualities, but knowledge on proper lighting condition depending on plant species and growth places would be necessary.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1992.12a
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• pp.23-24
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• 1992

식물공장에서 식물생산시 어떤 종류의 인공광을 사용하는가는 중요하다. 지금까지 연구는 HID(High Intensity Discharge)램프가 생육에 좋다고 하였으나, 실제로 너무 비싼 가격때문에 실제는 유럽의 농가에서도 이용되지 않고 있다. 본 연구는 자연광, 형광등, 백열등, 특수램프를 이용한 보광을 통해 광조건에 따른 백경채, 탑채, 상추, 쑥갓, 잎들께의 생육을 보고자 하였다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1995.04a
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• pp.79-80
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• 1995

원예작물의 재배에 있어서 인위적인 광질의 조절은 비현실적인 것으로 여겨져 왔으나, 시설피복자재의 발달과 인공광에 의한 보광재배 등은 시설원예에 있어서 광질조절의 가능성을 보여주고 있다. 본 실험은 광질에 따른 미나리의 생육반응을 조사하여 미나리 재배시 광질이용의 기초자료를 얻고자 실시하였다. (중략)

• Journal of Industrial Convergence
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• v.4 no.1
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• pp.67-85
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• 2006

The purpose of this study is to examine the effect of union's procedural justice and support on the millitancy. Results indicated that union member's procedural justice and interaction justice perceptions affect on the union support, and the union support has a positive effect on the millitancy Implications and limitations are discussed.

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.10a
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• pp.247-247
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• 2021