• Journal of Conservation Science
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• v.31 no.4
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• pp.443-455
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• 2015

To verifying the stability of Natural pigments for Dancheong which is available on the market was carried out as light resistance and gas corrosion test. In this particular case, we will confirm the characteristics of the only pigments except of Dancheong technique and influence of substance. Medium using for coloring are animal glue and synthetic resin that widely used for Dancheong in currently. Selected to artificial light source is a xenon arc lamp, contaminated gas is nitrogen dioxide gas in experiment. Degree of degradation of pigment were compared by measuring the degree of color change. The result of light resistance test, mineral pigments were good; color is green and blue type, soil pigments also good; color is yellow ocher, white clay, red clay etc. Gamboge, unghwang, cinnabar, red lead were confirmed not good. The result of gas corrosion test, most of the natural pigments were good condition except the red lead. Generally, animal glue samples had better than a synthetic resin samples.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.157-157
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• 2003

• Journal for History of Mathematics
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• v.32 no.3
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• pp.109-134
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• 2019

In order to improve the educational situation in which the natural number e and the natural logarithm are dealt with somewhat perfunctorily, this study explores the genetic process in which the natural logarithm and its base e occurred, and has an educational discussion based on that analysed process. Specifically, the study inquires into how the natural logarithm happened in relation to the quadrature of the hyperbolic curves through analysis and thought experimentation in mathematics history. Particularly, it sheds light on the role of e and the naturalness of the natural logarithm in terms of the introduction of the real number exponent. Also, this study discusses what the findings suggest educationally.

• Journal of the Optical Society of Korea
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• v.16 no.1
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• pp.36-41
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• 2012

Polymethylmethacrylate powders are commonly used to improve the spreadability and blurring effects of powder foundation cosmetics. In this study, the opacity and haze effect of four types of polymethylmethacrylate powders and their 10wt% powder foundation formulation was evaluated. The distorted random hemispherical particulates with both concave and convex portions showed the highest haze and opacity value as a single powder substance. And as a formulated phase, the powder foundation formulation containing particulates with fine pores provided the highest haze and opacity value. We also examined the quantity of reflected light over the angular range $20-75^{\circ}$ by polarized light goniophotometry. The total reflected light intensity, surface-reflected light, and internally reflected light were characterized. These studies demonstrated that hemispherical PMMA powders produce natural brilliance by creating high internally reflected light which is similar to the total reflection profile of artificial skin.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.4
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• pp.454-461
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• 2015

Light enhancement of GaN based light emitting diodes (LEDs) have been investigated by texturing the top p-GaN surface. Nano-textured LEDs have been fabricated using self-assembled Ni nano mask during dry etching process. Experimental results were further compared with simulation data. Three types of LEDs were fabricated: Conventional (planar LED), Surface nano-porous (porous LED) and Surface nano-cluster (cluster LED). Compared to planar LED there were about 100% and 54% enhancement of light output power for porous and cluster LED respectively at an injection current of 20 mA. Moreover, simulation result showed consistency with experimental result. The increased probability of light scattering at the nano-textured GaN-air interface is the major reason for increasing the light extraction efficiency.

• KIEAE Journal
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• v.9 no.1
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• pp.69-76
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• 2009

The use of natural light can improve the quality of indoor environment and also occupants health. In recent years, with an increasing awareness of sustainable development, various innovative methods of integrating daylight into the building have been developed. One such device is the light pipe system. The light pipes are innovative daylighting system that allow the transmission of daylight into the hard-to-reach indoor space. The system consist of mainly three parts. First, a top collector which is mounted on the outside of the roof and gathers skylight and sunlight. Second, light-reflective tube which is coated with highly reflective mirror finish material to transmit the daylight into the diffuser. Third, a diffuser which is installed on the ceiling in the room and spread the daylight into the room. Light pipes have been widely used and researched in many countries such as Australia, America, Canada and Britain. However, despite the significant daylight potential, little work have been carried out in Korea compare to the other countries. In this study, recent lighting technology and application of light pipe system in both Korea and other countries have been compared. For the results, the benefits of each light pipe system and suitable application in Korea is also discussed.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.3
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• pp.141-148
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• 2018

Photo-oxidation is one of the main causes of food deterioration of great variety of foods, such as dairy products, nuts, meat products, and wine. It causes a loss of both nutritional value and sensorial quality of products and may even leads to the formation of toxic compounds. Active packaging for food and beverages has been investigated and developed with embedding light absorbers or blocking materials into the plastics. In recent years, several novel light barrier materials have been proposed as an alternative option for different applications. This article reviews the up-to-date technology in light absorber and blocking material with special emphasis on chemical compound and mechanism. Inorganic, organic, hybrid organic-inorganic, and natural light absorbers were scoped. The challenges and future perspectives of light barrier materials are also discussed.

• The International Journal of Costume Culture
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• v.3 no.3
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• pp.212-222
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• 2000

This study intends to observe how the essential elements of art have changed Human's sense of beauty extending over the whole lives as well as fashion through the investigation of Light and Rays which have played a important role in giving birthe to the new trend of art within the upheaval age of various cultures. The peculiarities of which Futurism of Italy and Rayonism of Russia including Impressionism have a great role in giving birth to a new trend of art by means of the development of science technology are like these. Impressionists looked for the origin of the subtle harmony in nature within changes of sun-rays. The special feature of Impressionism paintings was to express the line of vision diversely according to changes of light rather than to focus on the line of vision with clear outlines. Henceforth, Neo-Impressionism which developed Impressionism more systematically leaded changes of Light and Rays more systematically and scientifically and maintained Divisionnisme techniques which extends to lead towards color and light through dividing and juxtaposing color. In the early 20th century Futurists tried to express dynamism through the interpenetration of light and revive color and light through the division techniques of color and persist an artificial light like eletricity rather than a natural light. Rayonism of Russia which was ifluenced from Impressionism and Futurism maintained intersection of reflecting rays which emerges from an object of things more deeply. This pursuit of light and rays also light and rays also appears as it is in modern fashion. First, it is the fashion which applied sun-rays persisted by Impressionists and expressed colors which show differently according to direction of light. Second, it is the fashion design which re-analyzed what Futurists expressed artificial light and rays. Third, it is the design which expressed Divisionnisme theory persisted by Impressionists and Futurists into fashion as it is and was made of being divided the form of glittering light into small dots. Fourth, it is the fashion design which applied Rayonists'work which applied intersection of reflected rays. Like this, it is aproved that the pursuit of light and rays expresses as it is in modern fashion of the 21st.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1182-1185
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• 2002

The objective of this study was to investigate the effect of long light regime (20 h light and 4 h dark, 20L:4D) and short light regime (4 h light and 20 h dark, 4L:20D) on egg production and egg characteristics of laying geese. Thirty-six laying birds, 4 replicates of 3 birds per treatment were allotted to three light regimes, i.e., 20L:4D, 4L:20D, and natural light (NAT) from March 7 to June 20. Results showed that the geese in 20L:4D consumed 54 g less feed per goose daily and laid 17.5 less eggs per goose (p<0.05) comparing to those in 4L:20D. The number of days from initiation of light treatment till cease of laying was 22 days shorter (p<0.05) in 20L:4D comparing to that in NAT. Five geese (41.7%) in 4L:20D kept laying by the end of applying light regime. Weight and surface area of the eggs in 4L:20D were greater (p<0.05) comparing to those in the other two light regimes. It is concluded that the period of egg production in goose could be manipulated by light regime in the ways such as using short light regime of 4 h light daily to prolong egg production through summer and using long light regime of 20 h light daily to induce cease of egg production.

• Journal of Forest and Environmental Science
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• v.17 no.1
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• pp.1-17
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• 2001

Forming a part of "Cooperative Practical Study for the Modernization of the Management of National Forest", this study was conducted to provide overall ecological information for the natural regeneration of major tree species on the basis of community structural attributes in the deciduous forest ecosystem. Followings are summarized characteristics of the natural regeneration for the selected tree species. Betula costata : Although large number of seeds are dispersed by wind, they require mineral soils to germinate. Thick litter layer could be an obstacle to germinate. After germination, the seedling requires large amount of light for successful establishment. Acer mono : Characterized by high shade tolerance and weak drought resistance, the seedling should be overcasted with more than 50% of canopy coverage. High stand density should be maintained to produce good quality of timber. The potential of coppice may be high. Ulmus laciniata : Since this species needs high rate of troll moisture and light, around 60% of canopy coverage should be maintained to retain moisture and incoming light. The competition with other vegetation should be removed for the favor of successful seedling establishment. Fraxinus mandshurica : This species requires moist mineral soils to germinate. After germination, the seedling needs large amount of light and moisture for successful establishment. Site preparation should be applied to reduce competition with weedy vegetation. Fraxinus rhynchophylla : Interval of large seed crops may be highly varied. Thick litter layer could be an obstacle to germinate. Site preparation should be applied to reduce competition with weedy vegetation so as to achieve successful seedling establishment. Quercus mongolica : Including the difficulty of seed supply by the consumption, thick litter layer and mountain bamboo cover could be the obstacle to germinate. More than 50% of relative light intensity is necessary to achieve successful seedling establishment. Kalopanax pictus : Thick litter layer could be an obstacle to germinate. The seedling needs large amount of light and moisture for successful establishment. Abies holophylla : In spite of high shade tolerance, the growth rate in sapling stage may be extremely slow. Cornus controversa : Seeds (drups) are consumed and dispersed by animals, tending to be not sufficient in seed supply. This species requires large amount of light for successful germination and seedling establishment. Tilia amurensis : The difficulty of seed supply might be expected with low seed purity and double dormancy. Since thick litter layer could be an obstacle to germinate, the species requires moist mineral soils for successful germination. The potential of coppice may be extremely high.