• Journal of Bio-Environment Control
• /
• v.9 no.4
• /
• pp.223-229
• /
• 2000

This study was conducted to analyze the opto-electric characteristics of light-emitting diodes(LED) designed for growth and morphogenesis control of transplant and to quantify the photon flux emittig from LED using a quantum sensor spectroradiometer. Difference in photon flux for blue and red LED between measured by a quantum sensor and measured by a spectroradiometer and numerically integrated was not observed. This result implies a spectroradiometer can be applied to quantify the photon flux emitting from far-red LED, which can not be measured using a quantum sensor. Since photon flux increases in proportion to wavelength, photon flux of LED modules arranged for red and far-red increased in proportion to wavelength, photon flux of LED modules arranged for red and rar-red increased gradually as the number of LED stick emitting far-red in LEd modules increased. Illumination of LED modules arranged for red and far-red decreased as the number of LED stick emitting far-red in LED modules increased. There was no difference in irradiance between LED modules arranged for red and far-red.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.3
• /
• pp.388-393
• /
• 2015

Buckwheat sprouts are a vegetable; a functional food should provide health benefit and enhance performance as high nutritionally important substances. Buckwheat noodles are the major buckwheat food in Japan, Korea and China. In addition, Buckwheat as preventive medicine has undergone a great advancement in the last decade. Comparison of the functional properties distribution and utilization in tatary buckwheat is required of understanding the metabolites. The study was conducted to identify the sorts of phenolic compounds and metabolites in tatary buckwheat seedling at 4, 7, and 10 days seedling under the different combinations of light-emitting diode (LED) such as blue, red, mix (red, blue, and white), dark, and natural lights in stem and leaves. After breaking the dormancy, buckwheat seeds were grown in culture room under lights for 14 hrs and the dark condition for 10 hrs, at $25^{\circ}C$ for 10 days. Length of buckwheat was gradually increased under all of the conditions. Using HPLC, rutin was highest at 7 days under mix and natural light in stem and leaf, respectively. Quercetin was highest at 4 and 7 days under natural light in both. Chlorogenic acid was highest at 7 days under mix and natural in stem and leaf, respectively. Taken Together, this study indicates that phenolic compounds and metabolites present in those plants could be helpful for the human health and nutritional additive.

• Journal of Food Hygiene and Safety
• /
• v.27 no.4
• /
• pp.442-448
• /
• 2012

This study investigated reduction of microbial population, water soluble pigment, capsanthin content, surface color (Hunter L, a, b, ${\Delta}E$), and sensory properties of pepper powder by LED (red, yellow, blue, green) treatments. LED (red, yellow, blue, green) treatment were conducted in 1,000 lux storage at $25^{\circ}C$ for 10 days. The total aerobic bacteria was no significant difference among the control and treated with LED during 10 days. In yellow LED treatment, yeast and molds were decreased about 1.76 log. Surface color such as lightness (L), redness (a), yellowness (b) were showed a decreasing tendency as the storage period. In the overall color difference (${\Delta}E$) of yellow LED treatment was lower less than 3.0. Water soluble pigment was no difference in control and LED treated samples during storage period. Capsanthin content was significantly decreased as storage period was increased, but no significant differences were observed among red and yellow LED treatments. Sensory properties of control was significantly reduced by storage period but yellow and green LED treatments were no significantly differences.

• Journal of Plant Biotechnology
• /
• v.35 no.3
• /
• pp.215-221
• /
• 2008

Effects of light generated by LEDs on shoot growth and rooting of Tsuru-rindo(Tripterospermum japonicum) were evaluated. Apical shoots(one or two node with 3-4 leaves) were cultured on MS basal medium with 3% sucrose and maintained for four weeks under five different light qualities: fluorescent lamp(F), 100% red LED(R), 70% red LED+30% blue LED(R7B3), 50% red LED+50% blue(R5B5), or 100% blue LED(B). Rooting was promoted by both red light and fluorescent lamp, and the effect was further promoted under the ventilation. Red light enhanced shoot node elongation, whereas blue light appeared to suppress it. Growth of shoots and leaves were enhanced under the ventilation irrespective of the different light qualities. Under the ventilated condition, total fresh weight of plants was highest in R7B3 LED as 257.7 mg per plant. Dry matters, which are used for index of plant growth, were lowest under red light, whereas it was highest under blue light. The dry matter was inclined to getting higher by ascending the ratio of blue light and red light. Total chlorophyll content was highest in both R7B3 LED and R5B5 LED under ventilation as 29.5 and 31.2, respectively. Above results suggest that light quality optimization could be an important factor to foster in vitro growth of the species. Ventilation treatment appeared to be another important factor to induce normal shoot growth and rooting.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.22 no.2
• /
• pp.123-133
• /
• 2020

Four LEDs (blue, green, red, and white light) were tested to identify the most attractive wave length to utilize as the forecasting tools for the B. tabaci in glass houses. Attractiveness was evaluated by the total number of the B. tabaci attached to a yellow sticky trap. In the condition of no host plant supplement, the attraction efficacy was ordered from high to low as blue light (107.3±2.5), white light (83.0±12.1), red light (58±21.8), and green light (39.7±8.1). In the supplement of the host plant, the attraction was observed in the order of blue light (52±17.4), red light (38.7±5.8), green light (12.7±1.5), and white light (11.7±5.0). In both experimental conditions, blue light showed the highest attraction. In terms of the host plant effect to LED attraction, it varied following as white light (85.9%), green light (68.1%), blue light (51.6%), and red light (33.3%). This result suggests that red light is the least affected by the host plant. In the evaluation of the relative control efficacy, it was determined following as red light (66.7%), blue light (48.5%), green light (31.9%) and white light (14.1%) (F_3,8 = 14.7, P = 0.001). Taken together, blue light had a very high initial attraction, and red light was revealed low attraction effect by the supplement of the host plant. In field demonstration experiments, a high attractive efficacy was not observed due to low-temperature conditions, but similar higher attractive efficacy was observed in blue and red lights compared to the control. The commercialization of LEDs using red and blue in the future is expected to provide important information regarding B. tabaci population density forecast in glass house.

• Journal of Mushroom
• /
• v.12 no.4
• /
• pp.375-378
• /
• 2014

The attractions of Lycoriella ingenua to different LED light sources were investigated in the mushroom cultivations which were located in Yongin of Gyeonggi-do province and Buyeo of Chungcheongnam-do Province. The LED light sources which were used in the investigations were white, green, red, blue and orange. Numbers of Lycoriella ingenua to LED lights in Yongin and Buyeo were 132.9 and 3,272.5 to white LED source, 120.3 and 3,109.5 to green LED source, 105.5 and 1,910.1 to red LED source, 88.3 and 2,708.3 to blue LED source and 46.7 and 2,465.5 to orange LED source, respectively. The numbers of Lycoriella ingenua to LED light sources were 2.7~3.5 times higher than the ones of untreated.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.3
• /
• pp.3-10
• /
• 2004

에디슨의 탄소 필라멘트 백열전구가 발명 된지 1세기가 지난 지금, 반도체 기술의 획기적인 발전에 의해 에디슨 시대의 종말을 예상하고 있다. “반도체 필라멘트”이라 불리는 고출력 LED(lighting emitting diode)를 이용한 반도체 조명이 바로 그 주역이다. 메모리에 사용되는 실리콘 반도체와는 달리, 빛을 낼 수 있는 화합물 반도체는 1962년 Holonyak이 GaAsP 적색 LED를 처음으로 개발한 이후, 주로 단순 표시기로 사용되었던 저휘도 LED의 발광효율이 화합물 반도체 공정 기술의 눈부신 발달로 인해 [그림 1]과 같이 Hainz's law에 따르면 휘도가 매 10년마다 30배씩 증가되어서 고취도 LED, 나아가서는 고출력 LED의 출현이 가능하게 되었다. (중략)

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.1
• /
• pp.70-74
• /
• 2015

An LED plant factory farm is an alternative way to grow crops regardless of weather, season, and blight in such times of climate change. In recent years, it is a currently active and vibrant research field. The industry, which ranges from leaf vegetables to high value products, is expanding. This study was conducted to test tthe response of LED (Light-emitting diode) irradiation on the growth characteristics and ginsenoside levels indoors, in order to find out suitable light conditions. Ginseng seedling was transplanted from a styrofoam pot ($L{\times}W{\times}D$:$495{\times}315{\times}215mm$, inside diameter) into a closed plant production system in four blue LED (BL) and red LED (RL) different ratios of 1:1, 1;2, 1:3, 1:4 in a temperature range of $20{\sim}25^{\circ}C$, relative humidity of between 55 and 65%, and a 12-hour photoperiod. The LED irradiation shows the highest levels were found at 1:1 of BL and RL ratio at $61.21{\mu}mol\;s^{-l}m^{-2}$, 1:2 ratio $68.55{\mu}mol\;s^{-l}m^{-2}$, 1:3 ratio $63.85{\mu}mol\;s^{-l}m^{-2}$ and 1:4 ratio $62.41{\mu}mol\;s^{-l}m^{-2}$ from highest to lowest respectively. After analyzing from shoot and root 2 yers old ginseng plant which were cultivated under 1:3 irradiation of BL and RL ratio, it generally showed a positive effect under a 1:3 ratio of BL and RL.

• Korean Chemical Engineering Research
• /
• v.49 no.3
• /
• pp.320-324
• /
• 2011

TOPO/TOP capped CdSe nanoparticles were synthesized via thermal-solvent method. The 540 nm green and 620 nm red emitting CdSe nanoparticles were obtained by controlling the reaction time and temperature. Phosphor conversion white LED was produced combining a 460 nm emitting InGaN LED chip as an excitation source with 540 and 620 nm CdSe nanoparticles as phosphors. The single or double phosphor layer was fabricated by mixing with epoxy, and investigated the effects on the luminous properties of the white LED. The single phosphor layer white LED showed 5.78 lm/W with CIE of (0.36, 0.45) in reddish white, and the double phosphor layer white LED showed 7.28 lm/W with that of (0.32, 0.34) in pure white at 20 mA. When the 400 nm near-UV LED was applied to optical pumping source, the luminous efficiency of white LED was enhanced to 8.76 lm/W.

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