• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.6
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• pp.92-100
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• 2002

This study was carried out to obtain fundamental information on the growth response of interior landscape plants under fluorescent light, sunlight and optical fiber lighting indoors. Saintpaulia ‘Delaware’, ‘Kalanchoe blossfeldiana, Anthurium scherzerianum and Ardisia crenata were examined using light intensity of 5001ux and 1,0001ux of fluorescent light, sunlight and optical fiber lighting in an interior environment. Results of experiments are as follows; 1) Plant growth status showed the best results under optical fiber lighting compared with fluorescent light or sunlight. 2) Plant growth status was better under 1,0001ux light intensity than 5001ux light intensity and in cases of the same light intensity, the highest growth increase was under optical fiber lighting. while it was showed relatively different according to the different plant species between a fluorescent light and sunlight. 3) The deep pinkish red color of Saintpaulia ‘Delaware’flower was obtained first under an optical fiber lighting and a fluorescent light, a sun light in that order. 4) Regarding interred activity, photosynthetic rate and transpiration rate, intercellular CO, water absorption rate showed a similar tendency generally in spite of a little difference. Namely, transpiration rate and intercellular CO, $CO_2$ a absorption rate increased according to increase of photosynthetic rate. 5) Photosynthetic rate of test plants except Anthurium scherzerianum increased according to increase of light intensity and increased highest under optical fiber lighting in the same light intensity condition. Increases differed under fluorescent light and sun light. That of Saineaulia ‘Delaware’and Anthurium scherzerianum increased in the order of optical fiber, fluorescent light and sun light, but that of Kalanchoe blossfeldiana and Ardisia pusilla increased in the order of optical fiber lighting, sun light and fluorescent light. Summing up these results, In visual value or internal health status of all experimental plants we obtained the highest result under an optical fiber lighting. Finally, we need to introduce an optical fiber lighting in interior landscape space as main light source.

• Journal of the Korean Solar Energy Society
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• v.30 no.1
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• pp.25-33
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• 2010

Use of daylight in underground space interacts with physiological need for human beings and provides relief from feeling secluded. Light pipe system can deliver natural light into the space where it is needed and can be used as primary or a secondary light source with benefits of energy, productivity and health. To use light pipe system effectively under various conditions, it is important to investigate the effectiveness of light pipe system with reliable monitoring protocol. This paper presents the results of light pipe system performance used in underground parking lot under different sky conditions. Comparisons were made between the illuminance standards of underground parking lot and the monitored data. The results indicated that adequate illuminance level was shown until 4.5m distance from the light pipe under clear sky condition. However, additional lighting device showed be used under overcast sky to meet the proper illuminance level.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.5
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• pp.519-524
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• 2009

This paper describes a new sensor system for 3D environment perception using stereo structured infrared light sources and a camera. Environment and obstacle sensing is the key issue for mobile robot localization and navigation. Laser scanners and infrared scanners cover $180^{\circ}$ and are accurate but too expensive. Those sensors use rotating light beams so that the range measurements are constrained on a plane. 3D measurements are much more useful in many ways for obstacle detection, map building and localization. Stereo vision is very common way of getting the depth information of 3D environment. However, it requires that the correspondence should be clearly identified and it also heavily depends on the light condition of the environment. Instead of using stereo camera, monocular camera and two projected infrared light sources are used in order to reduce the effects of the ambient light while getting 3D depth map. Modeling of the projected light pattern enabled precise estimation of the range. Two successive captures of the image with left and right infrared light projection provide several benefits, which include wider area of depth measurement, higher spatial resolution and the visibility perception.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.2
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• pp.236-242
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• 1986

The dependence of the current-voltage characteristics of hydrogenated amorphous silicon pin solar cells on the illumimination light intensity has been investigated. The open circuit voltage increases linearly with increasing the logarithm of light intensity up to AM 1, and nearly saturates above AM 1, indicating the open circuit voltage approaching the built-in potential of the pin solar cell above AM 1. The short circuit current density increase with light intensity in proportion to I**0.85 before and I**0.97 after light exposure. Since the series resistance devreses and shunt resistance increases with light intensily, the fill factor increases with light illumination. To increase the fill factor at high illumination in large area solar cells, t6he grid pattern on the ITO substrates should be made. Long light exposure on the solar cells gives rise to the increase of bulk resistance and defect states, resulting in the decrease of the fil factor and short circuit current density. The potential drop in the bulk of the a-Si:H pin solar cells at short circuit condition increases with decreasing temperature, and increases after long light exposure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.306-313
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• 2015

In this study, the change of optical characteristics was studied according to the micro optical pattern provided by photo lithography followed by thermal reflow process. The shape and luminance variation with micro pattern was evaluated by SEM and spectrometers. Also, we analyzed the luminance characteristics using the 3D-optical simulation (Optis works) program. As a result, we found that the radius of curvature(R) in micro pattern is decreased up to 77%($150^{\circ}C$) compared to the radius of curvature at the condition $100^{\circ}C$, which is caused by efficient reflow of organic material without chemical changes. The highest enhancement of brightness with optimum micro pattern was obtained at the condition of $120^{\circ}C$ reflow process. The brightness gain with optical micro patterns is more than 15% at the condition of R=16.95 um, ${\Theta}=77.14^{\circ}$ compared to original optical source. The results of light simulation with various radius of curvature and side angle of pattern shows the similar result of experiment evaluation of light behavior on optical micro patterns. It is regarded that the more effect on light enhancement was contributed by side angle which is effective factor on light reflection, rather than the curvature of micro-patterns.

• Textile Coloration and Finishing
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• v.20 no.6
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• pp.42-50
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• 2008

The objective of this study is to investigate the efficacy of pomegranate hull colorant as a natural hair coloring dye. The extract of pomegranate hull was concentrated and freeze-dried to get colorant powder. Effect of dyeing condition and mordanting on the dye uptake of hair by using Al, Fe, Cu, Cr, Sn compounds, color change and colorfastness were explored. In addition, tensile strength was measured and the surface of the hair was observed. Dye uptake of hair measured by K/S value (400 nm) indicated that ionic bonding seems to be involved in the sorption of pomegranate colorant to hair. Maximum sorption was obtained at pH 3.5 and the concentration of 50% (on the weight of hair, o.w.h.). Acidic dyeing condition (pH $3.5{\sim}5.0$) showed yellow color however alkaline dyeing condition (pH $7{\sim}11$) gave reddish yellow color. Pomegranate hull colorant produced greyish brown color on hair and the hair mordanted with Fe showed dark brown color. Mordants except Fe did not increase dye uptake significantly. Mordants except Cu increased light fastness and mordants except Cr increased washing fastness level slightly. According to SEM observation and the tensile strength retention measurement, the mordant dyed hair gave more damage to hair by ultraviolet light and washing than the hair dyed without mordanting. Experimental results of K/S value and colorfastness(light and washing) supported that pomegranate hull colorant without mordanting can be used as a semi-permanent natural hair coloring dye.

• Korean Journal of Environment and Ecology
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• v.12 no.1
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• pp.9-13
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• 1998

Because Lysimachia mauritiana is not able to maintain the seed viablity for a long time, it has difficulties in using for the ornamental plants or landscape gardening. This study was conducted to elucidate the optimal germination conditions of Lysimachia mauritiana seeds. The germination rate of the seeds was higer in light condition than in dark one. In experment determining the proper germination temperature, the germination rates were 2.2%, 96.9% and 91.2% under 35$\circ $C, 25$\circ $C, and 20$\circ $C, respectively in light condition. The approprate temperature for the germination was 25$\circ $C in light. The decreases of germination rate with the increase of the preservation periods was able to recover by priming pretreated with NaCl solution and KNO$_{3}$ + K$_{3}$H$_{2}$PO mixed solutions. When the storage period was 300 days, the germination rate was 75% without priming treatments. But the seeds primed with NaCl 0.1M and KNO$_{3}$ + K$_{3}$H$_{2}$PO mixed solutions 0.1M, showed germination rate above 90%. T$_{50}$ also was shorten from 5.25 without priming to 3.78 with NaCl 0.1M. Seed priming may induce earlier sprouts and increase germination rate of long-preserved seeds of native wild plants.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.82-87
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• 2009

In order to characterize the ecological traits of Quercus acutissima, Q. variabilis and Q. mongolica, which dominated in Korean mountain, we treated the sapling of the three oak species under the major environment factors (light, soil moisture and nutrient) with four gradient levels, for 8 months in glass house. Then we measured and analyzed the growth difference among them. The growth of Q. acutissima and Q. variabilis were increased with higher light intensity, but there is no apparent trend in Q. mongolica for light gradients. Q. mongolica did not show high reduction of growth, even in the lowest light intensity. Q. variabilis and Q. mongolica had a constant growth state to soil moisture treatment, but only Q. acutissima grew well in higher soil moisture gradient condition. All the growth of three oak species decreased with higher nutrient gradient condition. The growth reduction was increased in order of Q. variabilis, Q. mongolica and Q. acutissima. with increased nutrient gradient level. These results means that Q. mongolica, Q. acutissima and Q. variabilis have adaptation ability to shade, high moisture and low nutrient condition, respectively.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.493-499
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• 2006

In this study, we investigated the effect of growth regulators, seed priming, and light condition for the germination and early growth in Snapdragon (Antirrhinum majus L.). The optimum concentration of growth regulator for the promotion of germinability turned out to be 250 uM of $GA_3$. The germination enhancement in combination of $GA_3+BAP$ was not significant. The optimum priming condition for the maximum germinability was 2 day treatment of 200 mM of $KNO_3$. which increased germination by 14% and shortened the day to germination by 3.5 days. The optimum temperature for germination was $15{\sim}25^{\circ}C$. The germination frequency was decreased to lower than 20% at $30^{\circ}C$, which showed that seeds of Snapdragon germinates better at low temperature than high temperature. The germination frequency was different at light condition; it was low at dark condition, but was increased by $15{\sim}20%$ at red light condition. The combination of $GA_3$ and seed priming showed better germinability than the single treatment of $GA_3$ and seed priming.

• ALGAE
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• v.32 no.2
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• pp.139-153
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• 2017

The ability of a red tide species to take up nutrients is a critical factor affecting its red tide dynamics and species competition. Nutrient uptake by red tide species has been conventionally measured by incubating nutrient-depleted cells for a short period at 1 or 2 light intensities. This method may be applicable to certain conditions under which cells remain in oligotrophic water for a long time and high nutrients are suddenly introduced. Thus, a new method should be developed that can be applicable to the conditions under which cells are maintained in eutrophicated waters in healthy conditions and experience light and dark cycles and different light intensities during vertical migration. In this study, a new repletion method reflecting these conditions was developed. The nitrate uptake rates of the red tide dinoflagellate Prorocentrum micans originally maintained in nitrate repletion and depletion conditions as a function of nitrate concentration were measured. With increasing light intensity from 10 to $100{\mu}E\;m^{-2}s^{-1}$, the maximum nitrate uptake rate ($V_{max}$) of P. micans increased from 3.6 to $10.8 pM\;cell^{-1}d^{-1}$ and the half saturation constant ($K_{s-NO3}$) increased from 4.1 to $6.9{\mu}M$. At $20{\mu}E\;m^{-2}s^{-1}$, the $V_{max}$ and $K_{s-NO3}$ of P. micans originally maintained in a nitrate repletion condition were similar to those maintained in a nitrate depletion condition. Thus, differences in cells under nutrient repletion and depletion conditions may not affect $K_{s-NO3}$ and $V_{max}$. Moreover, different light intensities may cause differences in the nitrate uptake of migratory phototrophic dinoflagellates.