• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.12
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• pp.1-5
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• 2014

Since the "Light Pollution Prevention Act" was executed, the installation of the light cutoff panel to the security lightings which caused light trespass has been increased in the local government. The light cutoff panel is effective in reducing the light trespass in term of the cost-benefit. Because the installation of the light cutoff panel is inexpensive than the change of the security lighting. But the reflected light from the surface of the light cutoff panel has been regarded as another light pollution problem to solve. Therefore, we try to improve light cutoff panel by changing the light reflectivity characteristic of the surface of the light cutoff panel. First, we laminated the surface of light cutoff panel by black powder to reduce the light reflectivity of the light cutoff panel. After the black powder lamination, the light reflectivity on the light cutoff panel improved from 85% to 5%. And we compared reflected light caused by black powder laminated light cutoff panel with the one of no surface treatment cutoff panel. The vertical illuminance was measured at 3, 6, 9m in front of the security lighting and 3, 6, 9, 12, 15, 18m in back of the security lighting to evaluate the reflected light. And the measurement height was determined of 1.5m considering the height of the 1th floor of an apartment house. In this study, we found that the reflected light from the light cutoff panel can be reduced about 90% by the black powder lamination method. The results derived from this study will be helpful to develope the various kind of light cutoff panel which minimize the adverse effect like reflected light of light cutoff panel.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.1-1
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• 2000

This paper presents a holography through high scatter mediums. Femtosecond light pulses are used as object light and reference light. When light passes through a high scatter medium, there are ballistic light, snake light and difussive light in transmitting light. However, ballistic and snake light are very weak, difussive light is very stronge so that they can not be imaged directly, By using femtosecond laser electronic holographic gating method to gate ballistic light and snake light and multi-holograms processing technology, high quality images can be obtained. (omitted)

• Korean Institute of Interior Design Journal
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• v.19 no.4
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• pp.22-30
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• 2010

Light has primary function to enlighten the darkness. However, as development and progresses in media has caused big change in our life, the range of usage and application of light is broadened. And these days, light is actively used as a communication tool in a space. This thesis is based on an idea that a new prospect of light is required and at the same time the theoretical foundation should be established to take active advantage of light. In Chapter two, analysis criteria are established to verify study hypothesis. The applied methodology is to analysis the contents based on literature review. Key words related light in space design are extracted and the frequency of those key words are quantitatively measured. Taking advantage of the result, the characteristics of light are divided into three categories, 'light as symbolic information', 'light as communication medium' and 'light as topological form'. In chapter three, analysis of cases is performed. The cases are selected based on space analyzing criteria established in Chapter two. Qualitative analysis is performed on the cases categorized into natural light and artificial light. Basic analysis elements are evaluated for each case. And each case is allocated to one of three categories, 'light as symbolic information', 'light as communication medium' and 'light as topological form'. Through this analysis, it is found that light in space has prevailing characteristics of 'light as symbolic information' and 'light as communication medium'.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.6
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• pp.515-520
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• 2012

A daylighting system includes three parts; light collector, light transformer and light distributor. A DBLP(Double blind light pipe) daylighting system consists of a double blind light collector, a mirror duct type light transformer and a prism film light pipe distributor. The double blinds for a light collection are used to track the sun's altitude and azimuth movements throughout the day. Behind both sets of blinds is the light transformer, which is based on a rectangular cone shaped light duct. The light transformer was designed to efficiently deliver the light into the light pipe within a 30 degree radial spread for the efficient light into the distributor. In this study, DBLP system efficiency was simulated, evaluated and optimized by Tracepro as a popular ray trace light design simulation program. The results indicated that DBLP system efficiency evaluated a maximum 22.4% in case of Spring/Fall season solar noon time. While the overall average system efficiency in the morning and afternoon is evaluated about 10%.

• The Journal of Advanced Prosthodontics
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• v.4 no.2
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• pp.93-96
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• 2012

PURPOSE. The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units. MATERIALS AND METHODS. A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (${\alpha}$=.05). RESULTS. ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance ($P$ <.001). CONCLUSION. Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials.

• Journal of the Korean Society of Costume
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• v.58 no.2
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• pp.120-133
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• 2008

The purpose of this study is to analysis types of light and to find the characteristics of light in contemporary fashion design. In a scientific context, light is electromagnetic radiation of a wavelength that has the characteristics of straightness, reflection, refraction, scattering and diffraction. But in philosophical speculations, light has been used as a metaphor of 'being', 'to-be' or 'enlightenment.' And through the ages, people have tried to represent and apply the light into plastic art like painting and architecture. The types of light in fashion design was categorized as those; reflective light from the surface of clothing which is the result of interaction between illumination and material, representative light as the pattern of light or light effect such as sun or its rays and optical or psychedelic patterns, luminescent light from light emitting material like phosphorescence or LED which combines into fashion design, projective light from a medium to reveal virtual patterns on the surface or a fashion design itself using holography. These lights in fashion design can be considered as reflection of emphasis of sexuality, longing for fantasy and mystique, visualization of interaction and communication and groping for the play.

• The Korean Journal of Ecology
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• v.14 no.1
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• pp.87-99
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• 1991

Changes of phycobiliproteins(PBP) quantity and ferredoxin-NADP reductase(FNR) activity were investigated in various light illuminated cyanobacteria, Anabaena variabilis. PBP components were increased under blue light illumination, whereas decreased under red light illumination. PBP contents were twofolds in blue light than in red light. In view of the PBP composition, allophycocyanin(APC) in red light was higher 5.5% and phycoerythrocyanin(PEC) in blue light was higher 2.2% than in white light-illuminated PBP. It was suggested that PBP changes in bule light be the results of regulation of photosysthetic efficiency and protection of photosystem, whereas PBP changes in red light be effected by adaptation of adequate harvesting of light energy in photosystem. Changes of FNR activity were highest in red light, and sequenced lower to blue light and green light. It means that light-dependent production rate of NADP is the highest in red light. The difference of values was larger than that of values in comparison of red and blue light. It was suggested that increasing of FNR activity be due not to the function of isozyme, but to the synthesis of enzymes. Because of NAD/NADP regulation-effect to metabolism, it was considered that FNR activity might influence the metabolism indirectly and explain the probability of regulation in pathways of key enzyme activation. FNR activity was directly proportional to intensity of light. Optimum temperature and pH were about 25℃ and 7.5, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.319-323
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• 2015

This study investigated the effects of the light conditions on the productivity of scenedesmus dimorphus in the continuous mass cultivation system. To compare the algal productivity according to the light conditions, S. dimorphus was cultivated continuously under the wide range of light intensity(200-600 PPFD) and various light wavelength(white light and red-blue mixed light). After 100 days of cultivation under the different light intensity, the productivity of S. dimorphus increased as light intensity decreased. So, the productivity was maximized as 100 mg/L/d when light intensity was 200 PPFD. In case of light wavelength, the productivity of S. dimorphus was enhanced about 20% with the white light compared to that of the red-blue mixed light. Consequently, the optimal light conditions for the continuous mass cultivation of S. dimorphus were 200 PPFD as light intensity and white light as light wavelength.

• Journal of Plant Biology
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• v.33 no.3
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• pp.203-210
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• 1990

Effects of blue and red light on photorespiration in the leaf disks of pea were studied. The rate of total 14CO2 fixation was more or less higher under red light than blue light irradiation of the same quantum (94.8 $\mu$Em-2.S-1/mV). The release of 14CO2 by photorespiration was more stimulated under blue than red light. Among the photorespiratory intermediates, 14C was more incorporated ito serine under blue light than red light. However, 14C was more incorporated into glycine under red light than blue light. The incorporation of 14C into glycolate was very low under both light qualities, but higher under red light than blue light. Among the enzymes related to photorespiration, only glycolate oxidase was activated and/or synthesized by blue light irradiation. Moreover, more 14C2 was released from glycoate-1-14C under blue light than red light irradiation, but 14C2 release from glyoxylate-1-14C and glycine-1-14C showed no difference by the either light qualities. These results suggest that blue light is more effective in the photorespiratory CO2 evolution than red light. The reason is considered that glycolate is easily metabolized under blue light due to the stimulation of the glycolate oxidase activity.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.297-304
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• 2013

Purpose: To investigate blue light rejection and the percentage of blue light in the visible light of blue light blocking lens according to light source, and to study prescriptions for blue light blocking lens Methods: UV-VIS spectrophotometer was used for blue light rejection and the percentage of blue light in the visible light according to light source, and the percentage of blue light in solar light was used to evaluate the prescription for blue light blocking lens. Results: The blue light rejection and the percentage of blue light in the visible light of each lens were depending on light sources. Through the way to compare the percentages of blue light in the visible light passing through the lens with that in solar light, blue light blocking lenses suitable to each light source could been selected. Conclusions: In the prescription for blue light blocking lens, inquiry for user's display must be preceded. And then the percentages of blue light in the visible light passing through the lens based on that in solar light may be useful as a method of evaluating the prescription for blue light blocking lens.