• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.39-44
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• 1997

This study was conducted to determine the effects of growth regulators, temperature, and light on the germination of Chwinamul(Aster scaber, Aster tataricus, Synurus deltoides, Solidago virga-aurea var. asiatica, Ligularia fisheri) seeds. Compared to GA, IAA, and kinetin, BA (150ppm) stimulated best seed germination of all five species under the both light and dark condition at $25^{\circ}C$. The effect of growth regulators was not observed significantly under the light condition except of Ligularia fisheri and Synurus deltoides while it was shown markedly under the dark condition. Germination rates of Ligularia fisheri and Synurus deltoides in different concentration of BA were relatively higher under the light at $15^{\circ}C$ while those of other species varied in different concentration and temperature.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.188-191
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• 2013

This study was carried out to investigate the effects of light, temperature, and priming treatment on the germination of Bidens bipinnata seeds for the purpose of cultivation of new vegetable crop. The results showed that the treatment of $25^{\circ}C$ yielded the highest germination percentages and the highest germination speed in both light and dark conditions. Light condition had no effect on the germination of B. bipinnata. Priming treatments demon-strated the following improved germination percentages: $Ca(NO_3)_2$ 0.1 M (68.3%), $K_3PO_4$ 0.1 M (63.3%), and $KNO_3$ 0.1 M (53.3%), with $Ca(NO_3)_2$ 0.1 M treatment giving the greatest improvement. Consequentially, the results suggested that $25^{\circ}C$ light condition, and $K_3PO_4$ 0.1 M or $Ca(NO_3)_2$ 0.1 M priming treatments would be effective method to improve the germination of Bidens bipinnata seeds.

• The Journal of Korean Physical Therapy
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• v.12 no.1
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• pp.41-47
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• 2000

BACKGROUND AND PURPOSE. The purpose of this study is to investigate the effect of the disturbed vision on the gait distance parameters on the healthy young population. SUBJECTS. Twenty four healthy college aged individuals are randomly assigned to both a condition with a strobe light and the other condition without a strobe light. METHODS. The instrumentation used for gait analysis is the GaitRite electronic walkway system with a personal IBM computer. The examiner naked all the subjects to walk 6 times on the gait mat without the strobe light and. 6 times on the mat with the strobe light. The first 4 trials were practice and the last two trials were recorded in both conditions. The gait parameters analyzed were as follows : velocity, cadence, step length, and heel to heel base of support. RESULTS. Paired samples t-test used for this study did not found any significant differences between the two conditions because the p-values that were analyzed on the experiment were Utter than 0.05. The gait parameters that were analyzed included cadence, velocity, left and right heel to heel base of support, and left and right step length. DISCUSSION AND CONCLUSION. Based on this population, the condition of disturbed vision via the effect of the strobe light was not significantly challenging to compromise the body's sensory systems. However, in the elderly population, these systems can undergo age related changes. Visual changes rapidly decline in people 60 to 80 years of age and changes in the vestibular system include $20-40\%$ reduction in hair cells.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.439-445
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• 2017

Transplant production in a plant factory with artificial lighting provides several benefits; (1) rapid and uniform transplant production, (2) high production rate per unit area, and (3) production of disease free transplants production. To improve the growth of runner plants when strawberry transplants are produced in a plant factory, we conducted two experiments to investigate (1) the effect of different light intensity for stock and runner plants on the growth of runner plants, and (2) the effect of different container volume for runner plants on their growth. When the stock and runner plants were grown under nine different light conditions composed of three different light intensities (100, 200, and $400{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPF) for each stock and runner plants, increasing the light intensity for stock plants promoted the growth of runner plants, however, the growth of runner plants was not enhanced by increasing the light intensity for runner plants under same light intensity condition for stock plants. We also cultivated runner plants using plug trays with four different container volumes (21, 34, 73, and 150 mL) for 20 days after placing the stock plants, and found that using plug trays with lager container volume did not enhance the growth of runner plants. These results indicate that providing optimal condition for stock plants, rather than the runner plants, is more important for increasing the growth of the runner plants and that the efficiency of strawberry transplant production in a plant factory can be improved by decreasing light intensity or container volume for runner plants.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.93-102
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• 1996

The optical system of lens must be designed to tramsmit light over wide wavelength range and to have lower reflectivity in order to obtain higher spectral transmittance. However, the reflection color light appears due to the remain-reflection light in any optical system of lens. The wavelength of the reflection color light can be controlled by the structure of the number of layers, thickness of layer, reflective index, wavelength of incidence, and substrate etc. In the optical systems of the single layer and the double layers, the reflection color light appears in the condition of the anti-reflection of ${\lambda}s/{\lambda}$ = 1.0 by the color mixture of the remain-reflection lights in the ranges of the longer wavelength side and the shorter one of the ${\lambda}s/{\lambda}$ = 1.0, and of the double layers and triple layers, the reflection color light positioned at P1 < ${\lambda}s/{\lambda}$ < P2 appears in the condition of the antireflection of ${\lambda}s/{\lambda}$ = $PI{\ll}1$ and $P2{\gg}1$. In the optical system of the multi-layers, many antireflection points are existed at the various s/ values, and the reflection color light by the color mixture of the remain-reflection lights in the ranges except for the antireflection points.

• 한국해양학회지
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• v.21 no.2
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• pp.101-109
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• 1986

To clarify the light condition which influence phytoplankton ecology in Kyeonggi Bay, light intensity, compensation depth, extinction coefficient, transparency and suspended substances are studied from May 1981 to September 1982.Light intensities lie within adequate values for the phytoplankton growth from spring to autumn. However, in the winter season the light intensities show less than 4.8mw/$\textrm{cm}^2$ on the surface resulting lower than optimum irradiance. Light intensity could be a limiting factor for phytoplankton growth in winter. Compensation depths seasonally varied over an annual period in this study. Especially, in winter, compensation depths are confined to only 1-2m below the surface. Extinction coefficient(K) values are relatively high over an year cycle. K values is highest in winter and lowest in summer. Transparency shows seasonal variation. Tansparency is high in summer and low in winter. Thus low light intensity, low compensation depth, low transparency and high extinction coefficient in winter are due to the high turbidity and high concentrations of suspended substances. High concentrations of S.S. in winter result from the sediments and detritus resuspended by the winter turbulence induced by the strong winter winds and the convectional mixing. In summer, good light condition and low turbidity may result from the thermal stability of water mass preventing the resuspension of sediment particles.

• Korean Journal of Ecology and Environment
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• v.33 no.1 s.89
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• pp.9-22
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• 2000

The decomposition processes of Microcystis aeruginosa under the light and dark conditions were investigated in relation to the change of microcystins, physicochemical and biological factors. Cyanobacterial cells from upper stream of Lake Dae-chong were collected and incubated in the matrix of raw water under the light and dark conditions without additional nutrients. The decomposition of Microcystis cells started from beginning of the experiment and most of the cells were decomposed on 12th day. Under the light condition the concentration of toxins in filtrate fractionwas increased with the increase of viscosity as the decomposition of algal cells proceed whereas no significant change was observed under the dark condition. Microcystin- RR was most labile toxin than the other two microcystins because it was identified mainly in lyophilized cells but detected at trace level in the filtratefraction.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.455-457
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• 1999

In this paper, the wearing characteristics of current collecting shoes, interruption phenomena and contact resistances between collecting shoes and conductor rails are established as design parameters for development of the third rail current collector. An experimental analysis for established design parameters is performed as the materials of current collector shoe, contact force, sliding velocity and contact condition(dry/wet condition) between current collectors shoe and conductor rails. As a result of this study, the magnitude of contact force is in proportion to the amount of wear in the collecting shoe, but is in inverse proportion to the interruption and contact resistance between the collecting shoe and the conductor rail. And optimal values of design parameters are pre sented through analyzing the experimental results of the amount of wear, interruption and contact resistance.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.270-278
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• 2021

BACKGROUND: Horticultural plant growth under field and/or greenhouse conditions is affected by the climate changes (e.g., temperature, humidity, and rainfall). Therefore investigation of hydroponics on field horticultural crops is necessary for year-round production of the plants regardless of external environment changes under plant factory system with artificial light sources. METHODS AND RESULTS: Common sage (Salvia plebeia), nasturtium (Tropaeolum majus), and hooker chive (Allium hookeri) plants were hydroponically culturing in the plant factory with blue-red-white LEDs (Light-Emitting Diodes) and fluorescent lights (FLs). Leaf numbers of common sage under mixture LED and FL treatments were 134% and 98% greater, respectively than those in the greenhouse condition. In hooker chives, unfolded leaf numbers were 35% greater under the artificial lights and leaf elongation was inhibited by the conventional sunlight compared to the artificial light treatments. Absorption pattern of NO₃-N composition in hydroponic solution was not affected by the different light qualities. CONCLUSION(S): Plant factory system with different light qualities could be applied for fresh-leaf production of common sage, nasturtium, and hooker chive plants culturing under field and/or greenhouse. Controlled light qualities in the system resulted in significantly higher hydroponic growth of the plants comparing to conventional greenhouse condition in present.

• Design & Manufacturing
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• v.17 no.3
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• pp.8-14
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• 2023

In this study, basic research was conducted on manufacturing technology of thick-walled light guide a component that controls the light source of automobile lamps. As a preliminary study for manufacturing the final injection molded parts, a model for analyzing the influence of micro patterns on light guides is presented. The optical characteristics of the light guide were analyzed according to the change of the curvature radius of the micro-optical pattern, and the injection molding characteristics of the light guide according to the change of injection molding conditions were analytically evaluated. It was confirmed that the luminance uniformity improves as the R value decreases for changes in the micro-pattern R value, but it was confirmed that there are technical limitations in actual injection mold core processing and high-replication injection molding. Injection molding analysis showed that cooling channel design is very important compared to general injection molding due to thick-wall characteristics and thickness variation. It was also confirmed that the cooling channel has a great influence on the cycle time and birefringence result due to residual stress. As a result of analyzing the influence of filling time, holding condition, and cooling on shrinkage, it was found that the cooling water temperature has a significant effect on the shrinkage of ultra-fine light guide parts, and the holding condition also has a significant effect.