• 한국전기전자재료학회논문지
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• 제27권2호
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• pp.126-131
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• 2014

In this paper, plant crops used in the region to grow crops for the LED lighting area of a rectangle to fit the light distribution to maximize the efficiency of a rectangular distribution was made of LED lights. After the fabrication of LED lamps, light distribution, and in the area of $1.2m{\times}3m$ was the analysis of Illuminance chart. As a result of examining the performance light distribution for total Emin/Eav is 56%, and the target area of the light distribution compared to normal lamps Emin/Eav is improved by about 17%. In addition, plants grown in the area to minimize the outgoing light distribution can be focused on the cultivation area, according to the distance of the plants and be able to have the best luminous efficacy is judged.

• 한국전기전자재료학회논문지
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• 제12권1호
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• pp.75-80
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• 1999

In this study, we have investigated the relationship between the generation of pretilt angle and the polarization component in cells with UV light irradiation on polyimide (PI) surface. It was found that the generated pretilt angle is about $1.4^{\circ}$ with S-polarized UV light irradiation of $75^{\circ}$ on PI surface; it may be attributed to the asymmetry triangular of polymer surface with oblique S-polarized UV light irradiation on PI surface. Also, we measured that the generated pretilt angle is about $2.0^{\circ}$ with oblique P polarized UV light irradiation of $75^{\circ}$ on PI surface. Consequently, we suggest that the generated pretilt angle of the NLC is attributed to the interaction between the LC molecules and the polymer surface with oblique polarized UV light irradiation on PI surface.

• 한국실내디자인학회논문집
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• 제25호
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• pp.213-220
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• 2000

The meaning of light is not always developed aspect in process of architecture history as essence worth of the architecture. It means that architectural light is not affected simple development of civilization, but it has more complex aspect. The technology of applying architecture has continuous development of society that light is possible to extend quantity by development of technology because light is component not simple material or tools but strong worthy aspect, quality development of architecture comes true by exact understanding and application. Conversion from medieval society to modern society begins at the Industrial Revolution has new skills and materials, the architectural conform general space filled with non-characteristic light, and it gives rising to pursuit Utopia is not exist frequently. In result, light of metaphysical meaning is diminished and exterminated. In other hand light seems to be tools by development of technology in modern society, recovering its own meaning in other aspect. That light makes perfect image of architecture not by finite meaning only for simple space but by expressing strongly point that unify the whole architectural composition. Light is free from partial material of architecture. Light activates major composition through high-technology, and has possibility to carry out the essential worth animate architecture. The light expresses relative speciality for sense of place recognizes major component which the human being lives in and conform the real meaning of architecture.

• 한국실내디자인학회논문집
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• 제15권6호
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• pp.247-254
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• 2006

Apparently light does exist even if it does not have certain form that an object might have. The history of architecture can be told as the history of light. As various master architects as well as scholars mentioned, light has been recognized as one of the most important aspects in perceiving space. Although there are complex multi dimensions in body sense and perception, experiencing space through light is preliminary formed by the outline to the degree of brightness. Light gives space specific and unique character by limiting or enlarging the space by wrapping an object or by reflection of material surfaces or by the intensity of light itself. It is fundamentally important to recognize the essential relationship between light and perception of space through various medias such as material, form, movement and so on. Three types of space perception and cognition by light that have been categorized after studying the most significant writings on light become the core method to further analyze the selected case projects. In this research, we will study how interior space is expressed through different light conditions with above mentioned characteristics and how such expressions can be applicable to the design of interior space.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1805-1808
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• 2006

In this paper, we describe a versatile use of fullerene(C60) as a charge transporting material for organic light-emitting diodes. The use of fullerene as a buffer layer for an anode, a doping material for hole transport layer, and an electron transport layer was investigated. Fullerene improved the hole injection from an anode to a hole transport layer by lowering the interfacial energy barrier and enhanced the lifetime of the device as a doping material for a hole transport layer. In addition, it was also effective as an electron transporting material to get low driving voltage in the device.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.77-80
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• 2002

In order to enhence the photocurrent multiplication process, we controlled the irradiation light and the material of cathode layer of organic light emitting diodes (OLEDs). The structures of OLEDs were indium tin oxaide (ITO)/ copper(II) phthalocyanine (CuPc)/triphenyl-diamine (TPD)/ tris-(8-hydroxyquinoline)aluminum (Alq3)/ aluminum (Al). We found that OLEDs were changed by the photocurrent and free charge carrier multiplication process due to the irradiation of light. The rate of photocurrent was increased by the irradiation of red and blue light.

• Tribology and Lubricants
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• 제15권1호
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• pp.29-38
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• 1999

In recent years, the tribological behavior of coated ceramic material has been the issue of much interest. Particularly, the understanding of the tribological performance of thin film under light load is important for its potential in applications of MEMS. The friction and wear behavior of ceramic material that occur at light load depends on several factors such as surface roughness, contact area and material properties. In this work, the tribological behavior of coated silicon under light load and low speed was investigated. Particularly, the effects of coated materials, humidity and undulated surface were also studied. The results show that the effect of humidity on fiction was influenced by the apparent area of contact between the two surfaces. Also both adhesive and abrasive wear occurred depending on the sliding condition. Finally, undulations on the silicon wafer were found to be effective in trapping wear particles and resulted in the reduction of friction.

• 한국기계가공학회지
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• 제8권4호
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• pp.136-142
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• 2009

The vehicle's light-weight technology is divided into optimization of structure geometric and material. Structure geometric optimization and improvement of materials has examined to be power-train and maintenance on the severe condition. The core technology of Special vehicle's light-weight is constitute by Drop box, Axle and Final reduction gear. Technology and product of the parts is high to overseas and import dependency. We will want to examine the possibility of light-weight for the Axle Case and Drop box-connections. In this research, conventional design of excess weight will inhibit the mobility and fuel efficiency. Through the improvement of Axle material, we saw the possibility reducing weight. If you use the results of these studies, it will be available to domestic production technology and reducing weight of RV car, Dump truck, Track crain, etc.

• 한국전기전자재료학회논문지
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• 제18권11호
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• pp.1038-1042
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• 2005

We have investigated dielectric properties depending on bias voltage in organic light-emitting diodes using 8-hydroxyquinoline aluminum $(Alq_3)$ as an electron transport and emissive material. We analyzed the dielectric properties of organic light-emitting diodes using impedance of characteristics. Impedance characteristics was measured complex impedance Z and phase $\theta$ in the frequency range of 40 Hz to $10^8$ Hz. We obtained complex electrical conductivity, dielectric constant, and loss tangent $(tan\delta)$ of the device at room temperature. From these analyses, we are able to interpret a conduction mechanism and dielectric properties contributed by an interfacial and orientational polarization.

• 한국전기전자재료학회논문지
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• 제28권7호
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• pp.446-449
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• 2015

An improvement of light-extraction efficiency of organic light-emitting diodes was studied by using random-textured films (RTF). Device was made in a structure of RTF/glass/ITO/TPD/$Alq_3$/LiF/Al. RTF mold was made by spreading PDMS solution on a sandpaper. By pressing this mold on the glass substrate pre-coated with ZPU material, the RTF was obtained. From this study, there was an improvement of external quantum efficiency by about 30% in the device with the random-textured film (RTF 40) compared to that of the reference one.