• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1306-1311
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• 2011

Recombinant Rhodopseudomonas palustris, harboring the carotenoid-metabolizing gene crtI (CrtIBS), and whose color changes from greenish yellow to red in response to inorganic As(III), was cultured in transparent microplate wells illuminated with a light emitting diode (LED) array. The cells were seen to grow better under near-infrared light, when compared with cells illuminated with blue or green LEDs. The absorbance ratio of 525 to 425 nm after cultivation for 24 h, which reflects red carotenoid accumulation, increased with an increase in As(III) concentrations. The detection limit of cultures illuminated with near-infrared LED was 5 ${\mu}g$/l, which was equivalent to that of cultures in test tubes illuminated with an incandescent lamp. A near-infrared LED array, in combination with a microplate, enabled the simultaneous handling of multiple cultures, including CrtIBS and a control strain, for normalization by the illumination of those with equal photon flux densities. Thus, the introduction of a near-infrared LED array to the assay is advantageous for the monitoring of arsenic in natural water samples that may contain a number of unknown factors and, therefore, need normalization of the reporter event.

• 한국가구학회지
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• 제22권4호
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• pp.270-277
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• 2011

This study aims to find new solutions to the problem of utilization of materials and techniques represented in the development of modern lighting design. LED is an important component in modern lighting design and pine tree is one of the most popular domestic wood in furniture design in Korea. In this study, design is developed into various types of furniture such as a table, a chest, and a lighting, by researching manufacturing process and examining the use of slicing pine tree. The technique of slicing pine tree is a simple linear arrangement that was traditionally used in wooden furniture in Lee dynasty, with an emphasis on repetitive rhythm. The slicing technology is used to expand the usage of domestic pine tree. The beauty of natural wood is expressed with the transmission of light by applying this technique to the lighting design. It also brings new communication in between artificial lighting and natural wood combining this traditional technique and LED lighting in design. Finally, this study suggests particular value through the convergence of analog and digital by using the traditional wooden technique that keeps natural wood prints and new digital technology by using LED lighting. More discussions and research about this subject are expected continuously through this study.

• 대한환경공학회지
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• 제39권1호
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• pp.9-18
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• 2017

비소는 다양한 유해물질들 중 독성이 가장 크다고 알려져 있으며, 자연발생 또는 인간의 활동으로부터 비소오염이야기될 수 있다. 지하수 내 비소는 환원 환경에서 아비산염, 산화 환경에서 비산염 형태로 존재한다. 아비산염은 비산염보다 독성이 강하고 이동성이 더 크기 때문에 아비산염을 비산염으로 산화시켜 독성을 저감시키기 위한 연구가 많은 관심을 받고 있다. 본 연구에서는 비소로 오염된 지하수로부터 독성이 높은 아비산염을 독성이 낮은 비산염으로 산화시키기 위하여 자외선램프 및 자외선 LED 광원과 침철석 촉매를 이용한 광촉매 산화 공정에 대하여 연구하였다. 광산화 실험에서 광촉매로 사용된 침철석의 투여량이 0.05 g/L일 때 가장 높은 광산화 효율을 나타났다. 또한 광원의 파장별 겉보기 광산화 효율을 비교한 결과, 자외선램프가 자외선 LED에 비하여 아비산염의 산화 효율이 더 높은 것으로 나타났다. 하지만, 자외선 방사량을 기준으로 보정하면, 자외선 LED가 자외선램프보다 광산화 효율이 더 높은 것으로 평가되었다. 본 연구를 통해 침철석 광물이 존재하는 지하수 환경에서 외부로부터 다른 광촉매를 투여하지 않고 친환경적인 광산화 공정을 이용하여 비소의 독성 저감이 가능하다는 것을 알 수 있었다. 또한, 공정 또한 자외선 LED가 자외선램프의 단점을 보완할 수 있는 대체 광원으로 광산화 공정에 활용 가능하다는 것을 확인하였다.

• 생물환경조절학회지
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• 제19권3호
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• pp.140-146
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• 2010

본 연구는 4개의 생육상에서 주간온도 $20^{\circ}C$와 $25^{\circ}C$, 야간온도 5, 10, 15, $20^{\circ}C$의 주 야 온도 조합과 적색LED, 청색LED, 분홍LED(청색LED+적색LED), 백색LED 4종의 발광다이오드(LEDs)를 조사하여 산취(Chamecereus silvestrii f. variegata)선인장 '희망'의 모구 생육 및 발색에 가장 효과적인 재배환경을 찾고자 실시하였다. 주 야 온도처리가 황색 모구의 고유색 발현에 미치는 영향은 명도($L^*$값), 적색도($a^*$값), 황색도($b^*$값)가 모두 유의성이 있으며 특히 주간온도 $20^{\circ}C$와 야간온도 $20^{\circ}C$에서 모구색이 선명한 황색으로 관상가치가 가장 높았고, 주간온도 $25^{\circ}C$와 $5^{\circ}C$, $10^{\circ}C$ 각각의 야간온도에서 모구색 품질이 저하되는 것으로 나타났다. 발광다이오드(LEDs) 처리는 $a^*$값과 $b^*$값에서 유의적 차이가 있으며 적색LED에서 $a^*$값은 +5.23, $b^*$값은 +39.9로 산취선인장의 고유의 아름다운 황색 발색을 유지하며 구색품질이 가장 좋았다. 따라서 산취선인장의 모구색 발현에 영향을 주는 최적 온도범위와 발광다이오드(LEDs)는 주간온도 $20^{\circ}C$와 야간온도 $20^{\circ}C$이며 단색광인 적색 LED에서 가장 효과적이었다. 또한 산취선인장 재배에서 모구색의 외적 품질 향상은 적정 온도 환경 유지보다는 광질 환경을 개선하는 것이 보다 효율적이며 특히 발광다이오드(LEDs) 적색LED가 황색계통의 고유한 모구색 발현에 효과적인 것으로 나타났다.

• KIEAE Journal
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• 제13권2호
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• pp.61-66
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• 2013

This study is to eliminate the need for conventional high density plant factory's artificial light source such as LED to reduce the initial investment of the light source installation as well as the operation cost. Use of solar light could enhance the quality of the vegetables similar to those grown in the natural environment. Provision of solar light into the multilayer vegetable cultivation facilities and collecting maximum and sustainable sunlight without too much loss by tracing solar path and properly distributing it through careful control during daytime are crucial for realizing the investigated rooftop light shelf system for multi-layered vegetable cultivation. In this study, we developed an innovative way of effectively allocating sunlight inside even to otherwise shaded zone of a multi-layer vegetable cultivation facility. To prove the effectiveness of the system's sunlight collection and distribution capability, both simulation and experiment in Daejeon are performed and the outcome is analyzed.

• 한국태양에너지학회 논문집
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• 제34권3호
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• pp.66-74
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• 2014

In this paper, the performance of Hybrid Dimming control system for Daylighting system is evaluated by accredited tests. The system controls the balance of illuminance of daylight between daylight system and LED light system. It makes the normal illuminance of interior without the effects of weather by controlling the LED depending on the brightness of outside. For the tests, 6 diffusers($600{\times}300mm$) were installed in lighting area($36m^2$) and normal operation of the system sensors were tested about the interference of sunlight. The results of the examinations were satisfied with the criteria of accredited tests. Further research is the verification of energy saving effect by comparing the Hybrid Dimming control system to current artificial light system.

• Journal of Plant Biotechnology
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• 제41권3호
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• pp.123-126
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• 2014

This paper is suitable for household plant factory by design and using both energy-saving LED and solar technology. Conventional household plant factory only depending on natural sunlight is sensitive for the change of external environment. Another a big problem of conventional common household plant factory is large power consumption. Recently interest in wellbeing food such as chemical-free is increased abruptly. To solve these two problems, this paper describes hybrid type of household plant. In particular, reducing the power photosynthesis photon flux density (PPFD) is kept uniform to enhance the growth of the plant. Ambient light sensor is adopted for the control of proper combination of sunlight and LED to keep PPFD constant.

• Restorative Dentistry and Endodontics
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• 제43권2호
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• pp.22.1-22.9
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• 2018

Objectives: To evaluate and compare light-transmittance in dental tissues and dental composite restorations using the incremental double-layer technique with varying layer thickness. Materials and Methods: B1-colored natural teeth slabs were compared to dental restoration build-ups with A2D and B1E-colored nanofilled, supra-nanofilled, microfilled, and microhybrid composites. The enamel layer varied from 0.3, 0.5, or 1.2 mm thick, and the dentin layer was varied to provide a standardized 3.7 mm overall sample thickness (n = 10). All increments were light-cured to $16J/cm^2$ with a multi-wave LED (Valo, Ultradent). Using a spectrophotometer, the samples were irradiated by an RGB laser beam. A voltmeter recorded the light output signal to calculate the light-transmittance through the specimens. The data were analyzed using 1-way analysis of variance followed by the post hoc Tukey's test (p = 0.05). Results: Mean light-transmittance observed at thicker final layers of enamel were significantly lower than those observed at thinner final layers. Within 1.2 mm final enamel resin layer (FERL) thickness, all composites were similar to the dental tissues, with exception of the nanofilled composite. However, within 0.5 mm FERL thickness, only the suprananofilled composite showed no difference from the dental tissues. Within 0.3 mm FERL thickness, none of the composites were similar to the dental tissues. Conclusions: The supra-nanofilled composite had the most similar light-transmittance pattern when compared to the natural teeth. However, for other composites, thicker FERL have a greater chance to match the light-transmittance of natural dental tissues.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.184-184
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• 2022

This study was aimed to evaluate the antioxidant activity and bioactive property of extracts from a purple-colored wheat variety 'Arriheuk' (Triticum aestivum L.) wheatgrass, affected by light emitting diode irradiation (LED). The wheatgrass was cultivated for 10 days after sowing in a growth chamber under the following LED conditions: R1B1 (Red:Blue = 1:1), R7B3 (Red:Blue = 7:3), and R3B7 (Red:Blue = 3:7). We examined antioxidant activity of the hot water extracts of wheatgrass using DPPH and ABTS free radicals scavenging assays. At the concentration of 10,000 ㎍/ml, the extract from R1B1 showed the highest DPPH free radical scavenging activity(79.29%), but its ABTS free radical scavenging activity was the lowest(32.0%). To evaluate bioactive property of the wheatgrass, we examined the change of natural killer (NK) cell activity affected by the wheatgrass extracts in vitro. At the concentration of 500㎍/ml, NK cell activity was most highly enhanced by the extract from R1B1(181.6%), and the activity was 176.1% (R7B3) and 144.6%(R3B7), respectively. These results suggest that the functional property of 'Arriheuk' wheatgrass would be enhanced by LED irradiation condition.

• 한국유기농업학회지
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• 제26권3호
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• pp.515-532
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• 2018

Light is an essential and powerful element to animals. A light-emitting diode (LED) is most efficient in terms of economic benefits. The aim of the present study was to evaluate the effects of LED lighting time on milk production, milk composition, and the immune response of Holstein cows. Forty lactating cows were assigned to four experimental groups: control; natural daylight, treatment; am3-6, pm6-12 and pm6-am6. We found that there was no significant effect on the decrease ratio in milk production among the groups. Milk urea nitrogen (MUN) was significantly decreased in pm6-am6 and pm6-12 than the control. With regard to the hemolytic biochemical analysis, GLU was significantly increased and CRE, T-BIL were significantly decreased in the pm6-12 than the control. IGF-1 levels were significantly increased in pm6-12 compared to other groups. Besides, cortisol was significantly lowered in the pm6-12 than the control, while prolactin, IgA and IgG were not significant among the groups. In addition, catalase and glutathione peroxidase were also significantly increased in pm6-12 than the control. However, antioxidant enzyme activity and superoxide dismutase were not significant among the experimental groups. Therefore, it was concluded that LED lighting time had some impact on blood parameters and immune responses in dairy cows without any changes in milk production.