• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.226-233
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• 2023

High solar radiation in summer season causes excessive respiration of crops and reduces photosynthesis. In addition, the rainy season, which mainly occurs in summer, causes a low light condition inside the greenhouse. A low light condition can reduce crop growth and yield. This study was conducted to evaluate the effect of shade and supplemental lighting on the growth and yield of cucumber during summer season. Cucumber grafted seedlings were transplanted in two plastic greenhouses on August 30, 2022. To reduce the light intensity inside the greenhouse, a 50% shading screen was installed in one greenhouse. Supplemental lighting was conducted from September 7, 2022 to October 20, 2022. HPS (high-pressure sodium lamp), W LED (white LED, red:green:blue = 5:3:2), and RB LED (combined red and blue LED, red:blue = 7:3) were used for supplemental lighting sources, and non-treated (nonsupplemental lighting) was as the control. The supplemental lighting was conducted before sunrise and after sunset for 2 hours with a photosynthetic photon flux density of 150 ± 20 µmol·m^-2·s^-1. The plant height, leaf length, leaf width, and SPAD value tended to increase in the shading group. RB LED increased stem diameter regardless of shading treatment. Fresh and dry weights of fruits were not significantly different in shading and supplemental lighting. Average fresh weight of fruits was not significantly different among supplemental lighting as the harvest date passed. In conclusion, in this study 50% shade treatment significantly improved the growth of cucumber during the summer season. In addition, the growth and fruit characteristics are better than the control without supplemental lighting. This study can be used as basic research data for applying supplemental lighting technology to cucumber cultivation.

• The Optical Journal
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• s.139
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• pp.32-33
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• 2012

광학 측정 장비와 측정서비스를 제공하고 있는 독일 옵시라는 OSRAM의 파트너로 2년마다 개최되는 세계 최대규모의 국제조명전시회인 "light+building 2012"에 2012년 4월 15일부터 4월 20일 동안 참가하였다. 독일 프랑크푸르트에서 개최된 이번 전시회는 세계최대규모라는 명성에 걸맞게 전 세계 50개국에서 약 2,200여개 회사가 참여하여, 유럽의 선진조명 및 다양한 조명기술이 어떻게 건물의 실내외 디자인에 접목되어 쾌적한 주거환경과 생활환경을 제공하는지를 확인 할 수 있었다. 특히, 녹색성장이라는 세계적인 흐름에 편승하여 유명세를 타고 있는 LED와 새로운 광원으로 주목받고 있는 OLED까지, 조명산업과 관련이 있는 모든 제품에 대한 현재와 미래 트랜드를 한 눈에 볼 수 있는 자리여서 국내 조명산업에 종사자들도 이번 전시회를 많이 방문하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.342-347
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• 2016

This paper dealt with the economic analysis on the application of shipboard LED (Light Emitting Diode) luminaires to replace incandescent and fluorescent lamps, which account for over 80 % of light source on a training or naval vessel. The rates of savings achieved in the power consumption, initial investment, maintenance cost, and fuel cost were analyzed. The break-even points and the $CO_2$ emissions were also calculated. For the training vessel, the initial investment was increased by 3.8 times, while the maintenance cost over five years was reduced by 51 %. When 40 %, 50 %, and 60 % of luminaires were turned on, the calculated break-even points were 11 months, 9 months, and 7 months, respectively. On the other hand, the initial investment was increased by 3.5 times while the maintenance cost over five years was saved by 55 % for the naval vessel. The break-even points were calculated as 15 months, 12 months, and 10 months, respectively. Moreover, the $CO_2$ emissions of the training and the naval vessels were reduced by 69 % and 65 %, respectively. From the results, it was revealed that the maintenance cost can be reduced by more than 50 %, and that the power consumption, fuel cost, and $CO_2$ emissions can be reduced by more than 60 % if LED luminaires are used on two types of vessels.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.596-606
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• 2016

The growth and contents of anthocyanins and ascorbic acid in lettuce(Lactuca sativa L., 'Jeokchima') as affected by supplemental UV-A LED irradiation under different light quality and photoperiod conditions were analyzed in this study. Five light qualities, namely B (blue LED), R (red LED), BUV (blue LED+UV-A LED), RUV (red LED+UV-A LED) and Control (white fluorescent lamps) with photoperiods of 12/12 hours (day/night), 16/8 hours, or 20/4 hours were provided to investigate the effects of light quality and photoperiod on the growth and accumulation of anthocyanins and ascorbic acid in lettuce leaves. As measured 28 days after transplanting, the number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce were significantly affected by light quality and photoperiod. The number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce grown under R treatment increased with increasing light period. By contrast, leaf development was inhibited, but chlorophyll content increased, under B treatment. Supplemental UV-A irradiation significantly decreased leaf length, leaf width, leaf area and shoot fresh weight. Anthocyanins in lettuce increased significantly with decreasing dark period under B treatment. A synergistic effect of supplemental UV-A LED irradiation on anthocyanins accumulation was found for lettuce leaves grown under R treatment but not B treatment. Ascorbic acid in lettuce was greatly affected by photoperiod. Ascorbic acid content at BUV and RUV treatments increased by 20-30% compared to without UV-A LED irradiation. From these results, it was concluded that growth and contents of anthocyanins and ascorbic acid in lettuce are significantly affected by supplemental UV-A LED irradiation. The results obtained in this study will be informative for efforts to improve the nutritional value of leafy vegetables grown in plant factories.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1370-1374
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• 2015

Lighting improvements are needed for adequate operation of security installations according to the turn of scientific policing instead of human policing. The basic principles of security lighting is to provide sufficient lighting over a specific area so that anyone moving in or around can be seen easily. Also, in security lighting, illuminance and uniformity are to be considered for clearing of CCTV screen through the lighting improvement. To achieve such goals, each pole is to be considered of the height and the space of luminaries as well as the wattage and the type of lamps. In this paper, the lighting designs show the adequate operations of fence security systems through the actual measurement of illuminance by mock-up and the illuminance analyses for obtaining proper illuminance and uniformity value to keep brightness of CCTV screen able to confirm objects considering characteristics of CCTV monitor by simulations.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.26.2-26.2
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• 2010

최근에는 차세대 조명용 후보광원인 고출력 백색 LED를 개발하기 위한 경쟁이 치열하며, 이를 위해 업체가 고심하고 있는 가장 큰 문제 중의 하나가 칩에서 발생하는 열을 어떻게 관리하는가 하는 방열의 문제이다. 따라서, LED의 가장 큰 특징인 장수명을 손해보지 않기 위해서는 칩에서 발생되고 있는 열을 외부에 확산시키기 위한 기술 개발이 필수적이다. 다양한 방열소재 중 W-Cu 복합재는 W의 낮은 열팽창계수와 Cu의 높은 열전도도로 인해 방열소재로써 유망한 소재로 주목받고 있으나, 우수한 열적 특성을 발현하기 위해서는 고치밀화를 갖는 W-Cu 복합재 제조가 우선적으로 필요하다. W-Cu 복합체는 일반적으로 액상소결법을 통해 균일한 미세조직을 얻을 수 있으나, 열팽창계수를 낮추기 위해 Cu 함량이 적어지게 되면 치밀화가 어려우며 이를 해결하기 위해 나노입자를 갖는 분말을 이용하고자 하는 연구가 많이 진행되고 있다. 본 연구에서는 W과 Cu 산화물을 이용하는 것이 구성성분끼리의 편석이 발생하지 않으며, 소결성도 우수하여 양산화에 가장 접근한 방법으로 알려져 있다. 그러나, 지금까지의 얻어진 W-Cu 복합체의 경우, 분말상태에서의 얻어진 나노입자가 승온시에 마이크로 크기로 과도한 입자성장이 일어나기 때문에 소결 후에도 나노크기를 유지하기 어려울 뿐만 아니라, 구성상끼리의 응집체가 형성된다. 본 연구에서는 액상소결후에 W 입자가 Cu 기지내에 균일하게 분산되는 동시에 나노크기의 입자를 가지는 고분산 W-Cu 소결체를 얻고자 하였다. 이를 위해 금속산화물 분말의 분쇄를 위해 효과적인 방법으로 알려진 습식상태에서의 고에너지 볼밀링을 통하여 혼합된 텅스텐과 구리 산화물 분말의 수소환원공정을 통해 얻어진 100nm 이하의 입자를 가지는 W-20wt%Cu 나노복합분말을 출발분말로 사용하였다. W-20wt%Cu 나노복합분말의 성형체를 $1050^{\circ}C-1250^{\circ}C$의 온도범위에서 소결거동을 조사하였다. 그 결과, $1100^{\circ}C$ 온도에서 이론밀도에 가까운 소결밀도를 나타내었으며, 이는 기존에 비해 $100^{\circ}C$ 정도 치밀화 온도를 낮추는 결과이다. 소결체의 미세구조 관찰결과, 소결 후 약 200nm의 텅스텐 입자가 Cu내에 균일하게 분산되어 있었다. 제조된 W-Cu 시편에 대해서는 LED 응용성을 조사하기 위해 열전도도와 열팽창계수 등을 평가하였다.

• Food Science and Preservation
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• v.19 no.3
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• pp.354-360
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• 2012

The effect of the wavelength of the light emitted by the light-emitting diode (LED) on the growth characteristics and physicochemical and sensory qualities of Pleurotus eryngii were investigated. Pleurotus eryngii were grown under different light sources: blue light (450 nm), red light (650 nm), green light (525 nm), UV-A (365 nm), and mixed light ($B^*R$, $B^*G$, $R^*G$, $B^*R^*G^*UV-A$). The quantity of LED light was set up at 50% (LED: 64.9-108.0 $pmolm-2{\cdot}s-1$;fluorescentlight:11.7lux). Fluorescent light was used as control. There were no significant differences in the flesh firmness. In the case of the Pleurotuseryngii cultivated under red, green, and mixed light ($R^*G$), the color of the pileus and the length of the stipe were similar to those of the control group. The sensory scores were not significantly different between the LED lights (red, green, and $R^*G$) and the control. Among the three LED light conditions, the sample cultivated under red light recorded the highest score. The samples under UV-A, blue, and mixed light ($B^*R$, $B^*G$, $B^*R^*G^*U$) had a dark pileus color and had a short stipe. These results showed that the wavelength of LED light affected the growth and quality characteristics of Pleurotus eryngii, and that using red LED light is preferable for the cultivation of Pleurotus eryngii with better quality.

• Journal of Radiation Protection and Research
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• v.37 no.1
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• pp.10-15
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• 2012

Design and performance test results of a newly developed optically stimulated luminescence (OSL) measurement system are presented in this paper. Generally, different types of optical filters are used in OSL reader system to minimize the interference of the stimulation light in the OSL signal. For optically stimulation of $Al_2O_3:C$, we have arrived at an optimal combination of the filters, i.e., GG420 filter for filtering the stimulating light source, and a combined UG11 and BG39 filter at the detecting window (PMT). By using a high luminance blue LED (Luxeon V), sufficient luminous intensity could be obtained for optically stimulation. By using various control boards, the OSL reader device was successfully interfaced with a personal computer. A software was developed to deliver required commands to operate the OSL reader by using the LabView program (National Instruments, Inc.). In order to evaluate the reliability and the reproducibility of newly designed-OSL reader. Performance testing of the OSL reader was carried out for OSL efficiency, OSL decay curve and signal to noise ratio of the standard $Al_2O_3:C$ OSL material. It was found to be comparable with that of commercial Riso reader system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.713-716
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• 2008

This paper presents an automatic back-light brightness control system for mobile displays. One of the most important factors in mobile display is the power consumption due to the limited and movable power source. More than 80% of power of the LCD display is consumed by LED bark-light unit (BLU). The target brightness also becomes higher because of its moving picture and high resolution image, so there are some side effects for not only excessive power consumption but also ergonomic inconvenience in dark environment. To prevent this discomfort and reduce power consumption, this paper proposes automatic brightness control (ABC) technique in mobile displays. Developed system contains TFT-LCD panel with built-in photo sensor, driver IC capable of controlling photo sensor, and BLU. Since the photo sensor array built in panel detects automatically outdoor ambient light intensity, the power of BLU in dark environment is reduced. Developed ABC system showed reduced power consumption of 50% in dark environment. We believe that the proposed system is very useful to control power of mobile TFT-LCD.

• Smart Media Journal
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• v.5 no.4
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• pp.103-110
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• 2016

This study aims to establish the standards to give the design weight in case when developing equipment designs, by classifying products with similar purposes in accordance with the morphological characteristics and also extracting the typicality. Limiting the sampling group for the extraction of the typicality to a pendant-type and a ceiling buried-type through the preceding case study and consultation with experts, the survey was conducted for majors and relevant workers in six cities, sampling products released in Korea and Japan before May 2016. The 1st survey was about the Morphological classification, and the 2nd times about the extraction of the typicality while the 3rd one was about the classification of the morphological attributes. By drawing the design attributes based on the functional/morphological classification and formative principles, it aimed to establish the base of the future research on the measurement of design weight. The results of this study aim to efficiently establish the roles of design technology in accordance with changes in the lighting fixture market caused by the substitution of light sources, and also to draw the development direction to rapidly cope with the accelerated changes in lighting design types and corporate R&D.