• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.243-247
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• 2009

A Radioactive constraint of the nuclear fuel assembly irradiated by neutron during normal operation cycle of the nuclear power plant is typically on the order of about 3 kGy/h. In order to inspect nuclear fuel assembly using a VT (vision technology) system, the light such as halogen lamp is used. As the halogen lamp has lower color temperature than the sun light, the objects under halogen lamp illumination are seemed to be tinted with red. In this paper, high brightness LED is considered to be used as the light source of VT system. The high brightness LED, which is a key light source of the VT system, have been gamma irradiated at the dose rate of 4 kGy/h during two hours up to a total dose of 8 kGy. The radiation induced color-center in the LED housing cap made of plastics materials is observed.

• Solar Energy
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• v.10 no.2
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• pp.77-85
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• 1990

In the present analysis, a number of sun control devices are examined for their performance in promoting the interior visual environment. Two exemplary cases are introduced for their excellence in harnessing the concept of daylighting and passive concepts. Of these, the Johnson Controls branch office building in Salt Lake City manifests the effectiveness of light shelves and clerestory windows in implementing these concepts. Distinct optical characteristics are found for overhangs, light shelves, louvers, and blinds as they interfere with the path of sunlight. Substantial amount of energy could be saved if the fundamentals of these devices are truly understood in their application to residential and commercial buildings. Sustained efforts should be made in this regard by the builders, architects, energy consultants, and educators who make contributions in energy management.

• Molecules and Cells
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• v.24 no.1
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• pp.37-44
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• 2007

Three catalase cDNA clones were isolated from the small radish (Raphanus sativus L.). Their nucleotide and deduced amino acid sequences showed the greatest homology to those of Arabidopsis. Genomic Southern blot analysis, using RsCat1 cDNA as a probe, showed that catalases are encoded by small multigene family in the small radish. Nondenaturing polyacrylamide gels revealed the presence of several catalase isozymes, the levels of which varied among the organs examined. The isozyme activities were assigned the individual catalase genes by Northern analysis using total RNA from different organs. The three catalase genes were differentially expressed in response to treatments such as white light, xenobiotics, osmoticum, and UV. Their expression in seedlings was controlled by the circadian clock under a light/dark cycle and/or in constant light. Interestingly, RsCat1 transcripts peaked in the morning, while those of RsCat2 and RsCat3 peaked in the early evening. Our results suggest that the RsCat enzymes are involved in defense against the oxidative stress induced by environmental changes.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.785-792
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• 2023

Because hyperspectral imaging provides detailed spectral information across a broad range of wavelengths, it can be utilized in numerous applications, including environmental monitoring, food quality inspection, medical diagnosis, material identification, art authentication, and crime scene analysis. However, hyperspectral images often contain various types of distortions due to the environmental conditions during image acquisition, which necessitates the proper removal of these distortions through a data preprocessing process. In this study, a preprocessing method was investigated to effectively correct the distortion caused by artificial light sources used in indoor hyperspectral imaging. For this purpose, a halogen-tungsten artificial light source was installed indoors, and hyperspectral images were acquired. The acquired images were then corrected for distortion using a preprocessing that does not require complex auxiliary equipment. After the corrections were made, the results were analyzed. According to the analysis, a statistical transformation technique using mean and standard deviation with reference to a reference signal was found to be the most effective in correcting distortions caused by artificial light sources.

• ETRI Journal
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• v.31 no.1
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• pp.62-64
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• 2009

We report on the bias stability characteristics of transparent ZnO thin film transistors (TFTs) under visible light illumination. The transfer curve shows virtually no change under positive gate bias stress with light illumination, while it shows dramatic negative shifts under negative gate bias stress. The major mechanism of the bias stability under visible illumination of our ZnO TFTs is thought to be the charge trapping of photo-generated holes at the gate insulator and/or insulator/channel interface.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.172-177
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• 2007

In this paper, spherical aberration and light concentrating efficiency of lens was measured. The measuring system is applying spherical aberration occurrence principal and could measure a temperature at focal plane by using the thermocouple. The sun which is located in infinite distance and could makes parallel ray is used as a illuminant or heat source in experiments. It is confirmed that light concentrating efficiency of optical lens is in inverse proportion to spherical aberration and.

• Transactions on Electrical and Electronic Materials
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• v.16 no.4
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• pp.201-205
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• 2015

This paper dealt with the condensing technology of an LED light source that uses a parabolic reflector to replace a searchlight equipped with a xenon lamp. A ray-tracing simulation was conducted to analyze the influence of the diameter of the reflector and the size of the light source on light condensing. The combination of a parabolic reflector with a diameter of 620 mm and a focal distance of 220 mm, and a 9 mm multi-chip package (MCP) with a luminous flux of 7,000 lm showed the narrowest beam angle. The luminous intensity at the center was measured at 7.7×10⁶ cd. The distance between the light source and the point where the illuminance was 1 lx was calculated to be 2.8 km. The power consumption of the system was 95 W, which is only 9.5% of that of the 1 kW xenon searchlight, and the beam angle was 1.03°. In a site experiment, it was confirmed that the light ray reflected from the LED searchlight proceeds forward without any diffusion because of the narrow beam angle.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1225-1230
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• 2016

Since a flash light produces enormous amount of photon energy in short time, not only electro-optic and infrared(EO/IR) systems utilized for Intelligence Surveillance Target Acquisition and reconnaissance(ISTAR) activities but also the people of a combat field can be severely influenced by a high flash light bursting in front of them. The people who bumped into a flash could not escape such enormous amount of photon energy, resulting in being blind temporarily or even permanently. In order to investigate the effect of a high flash source on a human eye, it is essential to know how much photon energy be incident into an eye from the flash source. In this paper, the model of irradiated photon energy to individuals from some flashes is proposed. The proposed irradiated photon energy per unit area of retina is based on taking the situation to be modeled as a simple EO system in front of a flash light. The validity of proposed model was proved by the application of the model to human on the surface of the earth with the well known light source, the Sun. The model of this study can be utilized to simulate the retinal intensity and energy of a flash for various conditions such as the illumination levels, the distance from a flash busting site, luminous intensity and time of a flash.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1115-1119
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• 2005

The photoheterotrophic $H_2$ production of Rhodobacter sphaeroides was significantly increased through disruption of the genes coding for uptake hydrogenase and poly-${\beta}$-hydroxybutyrate (PHB) synthase (Lee et al., Appl. Microbiol. Biotechnol. 60: 147-153, 2002). In this work, we further removed the B800-850 light-harvesting (LH) complex from the strain and found an increase in $H_2$ production at the light-saturating cell growth (${\ge}10$ Watts $[W]/m^2$). Neither the mutant nor the wild-type produced more $H_2$ at the brighter light. Accordingly, light does not appear to be limited for the $H_2$ production by the presence of B800-850. However, increase in the level of the spectral complexes resulted in decrease of $H_2$ production. Thus, although the B875 is essential for light harvesting, the consumption of cellular energy for the synthesis of B800-850 and the surplus LH complexes may reduce the energy flow into the $H_2$ production of R. sphaeroides.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.221-225
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• 2011

Intensity-based optical fiber sensors are devised using a blocker which is located between two polymer optical fibers(POFs), one fiber is light-in and the other is light-out. This blocker is moved by an external displacement. Therefore, finding a general formulation of the relation between this displacement and transmission light intensity of various blockers is important to help develop intensity-based optical fiber sensors. In this paper, we consider blockers with arbitrary shapes from circular holes to inclined angled blockers. The transmission light intensities of such blockers should be determined by this generalized equation. In order to verify this equation, the calculated intensities of the blockers are compared with the values acquired from experiment. In the comparison, it is shown that the analytic equation can give the exact values of the transmitted light intensities for the assorted blockers. The range of the displacement measurement is also shown to be about 6 times of the radius of the hole in the case of a 9 degree inclined angle blocker.