• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.191-196
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• 2016

In order to establish the basic data for the growth of fish in the aquaculture industry, the behavior analysis of rockfish (Sebastes inermis) depending on the temperature and LED lights was conducted. In this study, water temperatures were set from $3^{\circ}C$ to $30^{\circ}C$ were used. One red light (wave length: 622 nm; light power: 811 mW) and one green lights (wave length: 518 nm; light power: 648 mW) were used. Behavior of the rockfish was expressed as average moving distance (AMD) for 1 minutes and a rate of movement. The mean AMD depending on the temperature was 1.0 m and the mean rates of movement was 50%. The mean AMD were 1.5 m, 1.9 m and 0.7 m in the red LED light, green LED light and control condition respectively. The mean rates of movement were 54%, 65% and 45% in the red LED light, green LED light and control condition respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.96-101
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• 2019

This study was conducted to investigate the effects of the light quality of a Light Emitting Diode (LED) on the phosphate uptake of Prasinophytes Tetraselmis suecica and Tetraselmis tetrathele. These species were exposed to a blue LED (max = 450 nm), a yellow LED (max = 590 nm), a red LED (max = 630 nm) and a fluorescent lamp (control) at $100{\mu}mol\;m^{-2}\;s^{-1}$. The maximum uptake rates (${\rho}_{max}$) of T. suecica and T. tetrathele under the red LED were $6.35pmol\;cell^{-1}\;hr^{-1}$ and $9.85pmol\;cell^{-1}\;hr^{-1}$, respectively. The half saturation constants (Ks) of two species were $9.43{\mu}M$ and $21.2{\mu}M$, respectively. The phosphate affinity of the two species under the red LED was higher than that of other wavelengths. Thus, the optimum light source to ensure economically effective and productive growth in a Tetraselmis culture system (Photo-Bioreactor) would be red LEDs because of the high growth rate shown, regardless of relatively low nutrient conditions.

• International Journal of Oral Biology
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• v.34 no.4
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• pp.185-190
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• 2009

This study examined the effects of red light generated from a light emitting diode (LED) upon proliferation and mitochondrial stress in human gingival fibroblasts (hGFs). Cells were exposed to LED-generated red light at a clinically relevant intensity and distance with a 610-630 nm wavelength for various times (0-48 min). At different exposure times, cells were processed for the analysis of succinate dehydrogenase (SDH) activity, proliferation, mitochondrial membrane potential (MMP) and cytotoxicity. Cell cycle progression was also investigated by flow cytometry after staining with propidium iodide. Red light exposure was found to inhibit SDH activity and DNA synthesis in hGFs in a time-dependent manner. Light exposure also reduced the MMP levels in these cells and this was closely associated with a $G_0/G_1$ arrest. In contrast, exposure of hGFs to red light for 48 min led to a dramatic loss of MMP with an attendant increase in cytotoxicity. These findings demonstrate that LED-generated red light may cause mitochondrial stress and growth inhibition in hGFs during tooth whitening therapy, depending on the length of the exposure.

• Journal of the Korean Vacuum Society
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• v.12 no.4
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• pp.235-238
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• 2003

Conventional LED displays use pixels which consist of red, green and blue LEDs of different operation voltages and degradation characteristics. Thus, the circuits are complicated and the display of each color changes independently with the operated time. In order to solve these drawbacks, an LED chip of a short wavelength and an LED lamp with the mixture of red, green, blue fluorescencers and epoxy on the LED chip were studied. The fluorescencers are excited by the light of the LED chip. The LED chip has an active layer of InGaN, a peak wavelength of 408 nm, a FWHM of 13 nm and the CIE index of (0.198, 0.087). White LED lamps were obtained and the CIE index change was observed with the change of the epoxy amount added to the fluorescencers.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.1
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• pp.99-112
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• 2020

A edible mushroom, Hypsizygus marmoreus is commercially cultivated. However, the researches of cultivation and physiological characteristics were not conducted in Korea. In this study, we conducted on artificial cultivation of H. marmoreus and elucidated the effect of light on the mycelial growth and fruit body development using LED light sources with different wavelength; blue (peak wave length 460nm), green(peak wave length 530nm), yellow(peak wave length 590nm), red(peak wave length 630nm), and white as positive control. Mycelial growth of H. marmoreus strains were inhibited about 30~40% in inhibition ratio under the illumination with blue, green, yellow LED light. However, red LED light was not inhibited. Elongation of stipe was effective under the long wave length such as yellow and red light. Abnormal fruit body was produced under the long wavelength and dark. However, development of pileus was effective under the short wavelength such as green and blue light. Also, as a result of cultivation with mixed light for high quality and harvest, many effective numbers and yields of fruiting bodies were obtained in the mixed treatment of blue and white light, and pileus developed well.

• Journal of Applied Biological Chemistry
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• v.59 no.2
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• pp.129-132
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• 2016

This study was conducted to evaluate the attraction effects of Sitophilus zeamais and Tribolium castaneum to light emitting diode (LED) trap in granary and compared with the black light bulb (BLB) trap, which is typical used in commercial trap. The red LED trap showed more attractive to S. zeamais and T. castaneum than that of the BLB. Moreover, the external condition of granary was about 1.5 times more attractive to S. zeamais and T. castaneum than the internal condition of granary. These results suggested that red LED trap could be useful to control S. zeamais and T. castaneum in granary.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.2
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• pp.552-559
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• 2017

To assess the effect of LED lights on marine microalgae growth in the laboatory, Tetraselmis suecica, Chaetoceros simplex and Isochrysis galbana were cultured under $20{\pm}1^{\circ}C$, Walne's medium and aeration using 3.6 L glass vessels. The LED light sources were Blue, Red, Blue+Red, CoolWhite and WarmWhite. The experiments were conducted three times. The density of microalgae was shown as the counted number of cells per day, and the specific growth rate was calculated by using the density. The statistical analysis was performed by analysis of variance using the SPSS 20.0 program. T. suecica culture was the highest density under the Blue LED light source, so the light source was the most effective for the growth of this alga. C. simplex and I. galbana culture had the highest density under the Blue+Red LED light source, therefore this light source was the most effective for the growth of these algae. The result of analysis of variance showed significant between groups.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.664-672
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• 2012

As an artificial light source, light-emitting diode (LED) with a short wavelength range can be used in closed-type plant production systems. Among various wavelength ranges in visible light, individual light spectra induce distinguishing influences on plant growth and development. In this study, we determined the effects of monochromatic LEDs on leaf shape index, growth and the accumulation of phytochemicals in a red leaf lettuce (Lactuca sativa L. 'Sunmang') and a green leaf lettuce (Lactuca sativa L. 'Grand rapid TBR'). Lettuce seedlings grown under normal growing conditions ($20^{\circ}C$, fluorescent lamp + high pressure sodium lamp, $130{\pm}5{\mu}mmol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 hours photoperiod) for 18 days were transferred into incubators at $20^{\circ}C$ equipped with various monochromatic LEDs (blue LED, 456 nm; green LED, 518 nm; red LED, 654 nm; white LED, 456 nm + 558 nm) under the same light intensity and photoperiod ($130{\pm}7{\mu}mmol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 hours photoperiod). Leaf length, leaf width, leaf area, fresh and dry weights of shoots and roots, shoot/root ratio, SPAD value, total phenolic concentration, antioxidant capacity, and the expression of a key gene involved in the biosynthesis of phenolic compounds, phenylalanine ammonia-lyase (PAL), were measured at 9 and 23 days after transplanting. The leaf shape indexes of both lettuce cultivars subjected to blue or white LEDs were similar with those of control during whole growth stage. However, red and green LEDs induced significantly higher leaf shape index than the other treatments. The green LED had a negative impact on the lettuce growth. Most of growth characteristics such as fresh and dry weights of shoots and leaf area were the highest in both cultivars subjected to red LED treatment. In case of red leaf lettuce plants, shoot fresh weight under red LED was 3.8 times higher than that under green LED at 23 days after transplanting. In contrast, the accumulation of chlorophyll, phenolics including antioxidants in lettuce plants showed an opposite trend compared with growth. SPAD value, total phenolic concentration, and antioxidant capacity of lettuce grown under blue LED were significantly higher than those under other LED treatments. In addition, PAL gene was remarkably activated by blue LED at 9 days after transplanting. Thus, this study suggested that the light quality using LEDs is a crucial factor for morphology, growth, and phytochemicals of two lettuce cultivars.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.56-64
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• 2013

Recent unusual weather due to global warming causes shortage of daily sunlight and constitutes one of the primary reasons for agricultural damages. LED light sources are frequently utilized to compensate for the shortage of sunlight in greenhouse agriculture. The present study is aimed at evaluating formations of phytochemicals as well as growth characteristics of mature strawberry fruits ('Daewang' cultivar) during cultivation in a closed growth chamber equipped with artificial LED light as a sole light source. Each LED light of blue (448 nm), red (634 and 661 nm) or mixed blue plus red (blue:red = 3:7) was separately supplied and the intensity of each light was adjusted to $200{\pm}1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at plant level with a photoperiod consisted of 16 hours light and 8 hours darkness. Strawberries grown under mixed LED light of blue and red wavelengths showed a higher production of fruits than those grown under other LED treatments. Fructose, one of the free sugars, increased in mixed LED light-grown fruits. Anthocyanin contents were elevated remarkably in the mixed LED light-grown fruits compared with those in other LED treatments. Contrastingly, contents of total phenolics and flavonoids were not of much different from one another among the fruits treated with various LED lights. On the other hand, ripening of strawberry fruits was found to be faster when grown under blue LED light compared with other LED treatments. Moreover, antioxidant activities of blue or red LED light-grown fruits, respectively, were significantly higher than those of mixed LED light-grown fruits. We suggest that when daylight is in shortage during cultivation in a greenhouse, supplementation of sunlight with LED light, which is composed of blue and red wavelengths, could be useful for the enhancement of productivity as well as of free sugar content in strawberry fruits. In addition, for the strawberry culture in the plant factory, selective adoption of LED light wavelength would be required to accomplish the purpose of controlling fruit maturation time as well as of enhancing contents of sugars and antioxidants of fruits.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.1-8
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• 2011

In this paper, the method to calculate chromaticity coordinate from spectral power distribution of LED is presented. Also, inverse tri-stimulus algorithm to find mixed luminance of red, green, blue LED from targeted luminance and chromaticity coordinate is proposed. Besides, digital light color control system of LED lamp applied this algorithm has been developed. In experiments, each chromaticity coordinate of red, green, blue LED calculated from this algorithm has relative percentage error of few % to measured values. Digital code is drawn from inverse tri-stimulus algorithm, and measured values of luminance and chromaticity coordinate of LED lamp digitally controlled by this code also have relative percentage error within a few % to targeted luminance and chromaticity coordinate.