• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.8
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• pp.395-401
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• 2015

Recently, many research studies have been carried out on the efficiency of light-shelf daylighting systems, especially comparing performance improvements and the limitations of reflective surfaces and their lighting performance. In this study, a crystal face reflective surface is proposed. The objective of the study is to evaluate the lighting performance of a crystal face light-shelf through a performance study. The performance study was carried out in a full scale test-bed in order to calculate the light distribution and energy consumption utilizing the standard indoor illumination as an index. The conclusions of the performance study are as follows. 1) The optimal angle of incidence for daylighting for both the operable flat type light-shelf and the crystal face light-shelf are taken in the natural environment on the dates of the winter and summer solstices, as well as the autumn and spring equinoxes. 2) The application and installation of the crystal face light-shelf can produce a 29.9%~34.3% increase of light distribution within the indoor space. However, the increase of light distribution can also lead to a decrease in the uniformity ratio, a design challenge that should be considered when applying a crystal face light-shelf. 3) It is possible to achieve a 7.98%~13.3% greater reduction in energy consumption when applying a crystal face light-shelf than when applying a flat type light-shelf. The increase in the number of crystal faces should concur with the analysis of the energy reduction. A limitation of the study is that only one predetermined pattern was performance tested for a crystal face light-shelf. In order to carry out further research on crystal face light-shelves, additional performance studies are needed based on alternative patterns and designs.

• Korean Institute of Interior Design Journal
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• v.26 no.1
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• pp.91-100
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• 2017

This study aims to comparatively analyze the characteristics of light expression shown in the exhibition spaces of architects Richard Meier and Kuma Kengo, who constructed the element of invisible light into visible forms within space, using diverse techniques and components. As for the methodology therefor, it was attempted to conduct theoretical consideration of light, to experience the spaces of light by producing diverse spaces with architectural space components, that is, space, form, material, structure, and color, and to find out what space characteristics are perceived by perceivers from the interaction of the components. As for the research scope, this study intended to identify the concepts and characteristics of light and compare light in spaces, focusing on works of Richard Meier who constructed functional and mechanical spaces based on Le Corbusier's architectural language in the West and works of Kuma Kengo who claimed regionalism architecture in the East. In particular, this study intended to comparatively analyze the methods of using materials according to the filtering of light that appears different between the two architects in case that light enters into their exhibition spaces, and the effects of light production that arise from the differences, thereby pointing out the characteristics of diverse light expressions within the spaces of modern architecture. On this, this study investigated methodological differences of the two architects, who are based on East and West thoughts, in expressing light in spaces in various forms through brightness and darkness, light transmission and shadows appearing according to the nature of light, and color and materials. It is hoped that this study will provide an opportunity for promoting better understanding about other architectural cultures as well as understanding the characteristics of light in exhibition spaces.

• Applied Chemistry
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• v.15 no.1
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• pp.17-20
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• 2011

A disposable light exposure detector kit has been developed by UV curing of a hydrogel material. The devised light exposure detector kit consisted of light sensitive structures, bottom plate, character sheet and sticky back plate. A light exposure detector kit has a serial light sensitive structures that contain various light sensitive dyes such as rhodamine and fluorescein. The light sensitive structure composed of UV curable hydrogel polymer material as a supporing material and photosensitive dye in a certain concentration. The fabrication procedure of the ligh exposure detector kit is very simple and fast due to UV curing procedure of a photopolymerizable hydrogel material such as poly(ethylene glycol) methyl ether acrylate (PEGMEA) and poly(ethylene glycol) diacrylate (PEGDA) with a photosensitive dye. By the proposed fabrication method, various size and shape of a light exposure detector kit could be fabricated using a flexible elastomer mold. Due to a fast and inexpensive fabrication method, the light exposure detector kit could be use a single use for various industrial applications. According to light irradation, the light sensitive structure on a light exposure detector kit could be lose its color by decomposition of a photosensitive dye chemical in the structure. Thus the amount of the exposed light on a substrate could easily be recognised by changing color or transparency of the structure.

• KIPE Magazine
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• v.6 no.4
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• pp.21-26
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• 2001

HVDC Light는 300MW에 이르는 전력을 가지고 있는 아불 성형된 DC Cable과 Voltage Source 컨버터에 기반을 둔 가장 최근의 HVDC 기술이다. HVDC Light 컨버터는 IGBT(Insulated Gate bi-polar Transistor)와 유효전력과 무효전력 사이의 고속 컨트롤을 위한 PWM(펄스 폭 변조)의 기능을 가지고 있다. HVDC Light 케이블은 압출 성형된 폴리머의 절연을 가진 케이블이며 직류 전압을 위해 특별히 개조되었다. 전력 범위 내에서 HVDC Light 컨버터와 케이블은 지중 또는 해저 송전 등에서도 송전전력을 위해 훌륭하게 조합될 수 있었다. 본 원고는 실제의 케이스로부터 얻은 경험지식으로, HVDC Light 기술의 조합을 사용해 해결된 문제점을 소개하고, HVDC Light의 장점을 설명하였다.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.578.1-578
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• 2001

The aim of this study was to evaluate the efficiency of the recently introduced light curing units to polymerize a light curing resin composite. Four light curing units XL 3000, Optilux 500 for halogen light source, Apollo 95E for plasma arc and Easy cure for LED (blue-light Emitting Diode) were evaluated. Radiometer was used for measure the light intensity.(omitted)

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.123-127
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• 2013

BACKGROUND: The incandescent bulb and compact fluorescent lamp are widely using as a light sources for daylength extension of chrysanthemum. But, these light sources consume a lot of electricity and have short longevity. A light-emitting diode (LED) is a semi conductor light source. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime. In this study, we investigated the intensity of red light to control flowering of chrysanthemum (Dendranthema grandiflorum cv. "Shinma") by using LEDs. METHODS AND RESULTS: The red (660 nm) and far-red (730 nm) light were irradiated subsequently to investigate photo-reversible flowering responses of chrysanthemum. The flowering of chrysanthemum was inhibited by night interruption with red light but subsequently irradiated far-red light induced the flowering of chrysanthemum. This photoreversibility, reversion of the inductive effect of a brief red light pulse by a subsequent far-red light pulse, is a property of photo responses regulated by the plant photoreceptor phytochrome B. Four different intensity of red light of 0.7, 1.4, 2.1, and $2.8{\mu}mol/m^2/s$ (PAR) were irradiated at growth room in order to determine the threshold for floral inhibition of chrysanthemum. Over $1.4{\mu}mol/m^2/s$ of the red lights irradiated chrysanthemums were not flowered. The plant length, fresh weight, number of leaves, and leaf area of chrysanthemum irradiated with red light were increased by 17%, 36%, 11%, and 48%, respectively, compared to those of compact fluorescent lamp. CONCLUSION(S): The red light and subsequential far-red light showed that the photoreversibility on flowering of chrysanthemum. The red light ($1.4{\mu}mol/m^2/s$ of red LEDs) and white light (50 Lux of compact fluorescent lamp) have the same effect on inhibition of flowering in chrysanthemum. Additionally, the red light increased the plant height and dry weight of chrysanthemum.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.643-656
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• 1996

Various light intensity and light quality were treated to oat seedlings to investigate the effect of light on the chlorophyll accumulation and the formation of chlorophyll-protein complexes. The Increase of total chlorophyll accumulation and Chl (chlorophyll) a/b ratio was promoted under H (high intensity) white light during oat chloroplast development when compared to 1 (low intensity) white light. Also H white light was more effective in the formation of chlorophyll-protein complexes associated with PSI CCI and CCII than L white light. The seedlings grown in various right quality caused little changes in total chiorophyl and ChI-a/b ratio when compared to those grown in L white light. The assembly of LHCII trimer was more affected by L white light treatment in the formation of-chlorophyll-protein complexes than red light treatment. The effect of blue light on the relative composition of chlorophyll-protein complexes was similar to that of L white light. Particualrly, blue light was more effective in the synthesis of LHCII monomer than the other light quality at the early stage of greening. When compared to red light, blue light was more effective the increase of chlorophyll accumulation and Chl a/b ratio than 1ight Quality, and light Quality may be in important factor for the regulation of the organization in the chlorophyll-protein complexes curing greening.

• KIEAE Journal
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• v.17 no.3
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• pp.83-90
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• 2017

Purpose: With the increase in the energy consumption in the building sector, many studies have recently been conducted to address this issue. Due to its efficiency, diverse studies on a light-shelf, which is a natural lighting system, are in progress. However, there has been no research on the external illumination that determines the performance of a light-shelf. Therefore, the present study aimed to prepare the external illumination standard for securing the lighting performance of a light-shelf through the light-shelf performance evaluation based on a 1:1 scale testbed, and to suggest a height-adjustable light-shelf based on an open and closed concept for the case in which the lighting performance of the light-shelf significantly deteriorates, by collecting the external illumination. Method: In this study, a 1:1 scale testbed was established for performance evaluation, and the external illumination standard for securing the performance of the light-shelf was prepared by comparing the lighting performance of the light-shelf depending on the open and closed condition of the light-shelf and the external illumination. Result: 1) In this study, a light-shelf that can be opened or closed depending on the external illumination was suggested. As a result, the prospect right can be secured by creating the condition where there is no light-shelf installation by moving the light-shelf to the top of the window when the lighting performance is not secured. 2) In the summer solstice, the external illuminations appropriate for lighting energy reduction were more than 75,000 lx and 60,000 lx for the light-shelf width of 0.3 m and 0.6 m, respectively. 3) In the intermediate period, the external illumination appropriate for lighting energy reduction was 60,000 lx. In the winter solstice, making the condition where there is no light-shelf installation by closing the light-shelf would be appropriate. 4) Based on the aforementioned results, the external illumination standard for the opening and closing of the height-adjustable light-shelf based on an open and closed concept suggested in this study was 60,000 lx, and the light-shelf with a width of 0.6 m would be advantageous for lighting energy reduction.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.62-62
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• 2020

Ginseng is a shade-plant cultivated using shading facilities. However, at too low light levels, root growth is poor, and at high light levels, the destruction of chlorophyll reduces the photosynthesis efficiency due to leaf burn and early fall leaves. The ginseng has a lightsaturation point of 12,000~15,000 lux when grown at 15 to 20℃ and 9,500 lux at 25℃. This study was conducted to select the optimal light intensity of 3-year-old ginseng grown in blue-white film plastic house. The seeds were planted in the blue-white film plastic house with different light receiving rate (March 17, 2020). Between April and September, the average air temperature in the house was 20.4-20.7℃. Average soil temperature was 18.3℃-18.5℃. The chemical properties of the test soil was as follows. The pH level was 7.0-7.4, EC was 0.5-0.6 dS/m, OM was at the levels of 33.6-37.7 g/kg, P₂O₅ was 513.0-590.8 mg/kg, slightly higher than the allowable 400 mg/kg. The amount of light intensity, illuminance, and solar radiation in the blue-white film house was increased as the light-receiving rate increased and the amount of light intensity was found to be 9-14% compared to the open field, 8-13% illuminance and 9-14% solar irradiation respectively. The photosynthesis rate was the lowest at 3.1 µmolCO²/m²/s in the 9% light blue-white plastic house and 4.2 and 4.0 µmolCO²/m²/s in the 12% and 14% light blue-white plastic house, respectively. These results generally indicate that the photosynthesis of plants increases with the amount of light, but the ginseng has a lower light saturation point at high temperatures, and the higher the amount of light, the lower the photosynthetic efficiency. The SPAD (chlorophyll content) value decreased as the increase of light-receiving rate, and was the highest at 32.7 in 9% light blue-white plastic house. Ginseng germination started on April 11 and took 13-15 days to germinate. The overall germination rate was 82.9-85.8%. The plant height and length of stem were long in the 9% light-receiving plastic house. The diameter of stem was thick in the 12-14% light-receiving plastic house. In the 12% and 14% light-receiving plastic house, the length and diameter of taproot was long and thick, so the fresh weight of root per plant was 20 g or more, which was heavier than 16.9 g of the 9% light-receiving plastic house. The disease incidence (Alternaria blight, Gray mold and Damping-off etc.) rate were 0.9-2.7%. The incidence of Sclerotinia rot disease was 7.5-8.4%, and root rot was 0-20.0%. The incidence ratio of rusty root ginseng was 34.4-38.7% level, which was an increase from the previous year's 15% level.

• Natural Product Sciences
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• v.2 no.2
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• pp.90-95
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• 1996

When reserpine-producing cell strains of Rauwolfia serpentina were transferred from the dark to the light irradiation, the production of reserpine was extremely enhanced whereas the cell growth was suppressed. In an incubation period of 20 days, the most effective culture condition for reserpine production was the combination of 8 days of dark culture and following 12 days of light culture. The time courses of both cell growth and reserpine production were measured in vitro in order to clarify the effect of wave length range of light on the biosynthesis of reserpine. Although the growth of cultured cells which had been incubated under continuous red, yellow, and green lights, respectively, was similar to that of the cultured cells subcultured in the dark. The cells cultured under red light irradiation produced less reserpine than dark-grown cultures. Both blue and near-ultraviolet light inhibited the growth of cultured cells. The production of reserpine was strikingly enhanced by blue light, but was strongly inhibited by near-ultraviolet light.