• The Journal of Korean Academy of Prosthodontics
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• v.38 no.6
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• pp.821-828
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• 2000

Metal - ceramic restorations have been the standard of fixed oral rehabilitation for over 30 years, and while many advances have been made in materials and research, the esthetic challenges of the light reflective metal substructure will always put clinician in an esthetic dilemma, for only a very talented ceramist / dentist team can create esthetics that rival nature on a repeatable basis. All ceramic restorations have also been a choice in our restorative armamentarium, but in the past, the materials have also had their own limitation, number on being question-able strength to withstand occlusal forces generated during mastication. IPS Empress 2 offers dentistry a metal free alternative to traditional restorative techniques. This clinical report describes the treatment of patients with esthetic problem of anterior dentition using Empress 2 system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.13-16
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• 2008

The aim of this study is to analyze the daylight performance at Changdeokgung Nakseonjae that is the representative and most well preserved Korean royal palace. As a result of measuring illuminance and luminance, direct sunlight is cut off by the eaves and reflective light from the court comes in the inside of the upper floor. As the layer of window is increased, daylight is decreased and the illuminance distribution is more stable because of decreasing of illuminance change. This study would be used as preliminary data for applying characteristics of lighting environment of Korean royal palace to modern architecture.

• Journal of the Semiconductor & Display Technology
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• v.12 no.3
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• pp.35-39
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• 2013

In this paper, we developed an optical sheet for LED lighting with integrated $CO_2$ gas and temperature sensor which can monitor at the indoor environment. The optical sheet for LED lighting is fabricated through PMMA(Polymethyl methacrylate) injection process using mold. This research enables to fabricate the reflective sheet, light-guide plate and the prism sheet in a optical sheet. The fabricated sheet demonstrates higher intensity of optical efficiency compared with single-sided sheets. The $CO_2$ sensor was fabricated using NDIR(NON-Dispersive Infrared) method and it has $0.0235mV/V{\cdot}PPM$ sensitivity. The temperature sensor was fabricated using RTD(Resistance temperature detector) method and it has $0.563{\Omega}/^{\circ}C $sensitivity.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.160-162
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• 2004

The aim of this study is to make the technical standards for certificating a high efficiency metal-halide lamps and reflectors using the high intensity discharge lamps, to accomplish the practical energy saving effect. Metal-halide lamps are certificated by stabilzed and restarting time, lamp voltage, current, power and light output efficiency. The high illumination reflectors using HID lamps are certificated by testing reflective index, fading, the melting point, glare and install spacing factor.

• Journal of the Optical Society of Korea
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• v.4 no.1
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• pp.62-65
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• 2000

A new type of multi-viewing zone screen for multiview 3-D display is described. The screen is made by stacking a Fresnel lens and a reflective prism array plate. The screen performs both focusing and beam dividing functions and directs very narrow light beams to three viewing zones for three spectators. The results of experimental testing of the screen have demonstrated that current technology of Fresnel lens and prism grooves on PMMA(Ploymethyl Methacrylate) allows manufacture of screen having a pixel size of about 1-2 mm. This size is reasonable enough for a screen with dimensions about 1m size. Optical qualities of Fresnel lenses and grooved prism arrays achieve an angular resolution for the screen of several angular minutes.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.406-409
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• 1999

Thin films of silver with high reflectance of 95% and above were fabricated successfully on polyester substrate by using e-beam evaporation processes. The optimum process condition was investigated by varying the current values applied while keeping the substrate temperature at room temperature by circulating the cooling water around it during deposition. Thin films of silver deposited with 30 mA as current revealed the highest reflectance of 96.4%, while being illuminated with a light of 700nm wave-length. But their adhesion showed unsatisfactory results. Though the films showed a condensation type in the cross-sectional views, they revealed crystallinity in the planes of (111) and (200) and growth orientation in <100> direction.

• Journal of Magnetics
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• v.12 no.2
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• pp.77-80
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• 2007

Recently there was a proposal for a spin filter by using the spin superlattice structure. In a certain energy range, the proposed structure exhibits a high spin filtering efficiency close to 100%. Unfortunately such energy range turns out to be narrow. In this paper, we report a method to widen the energy range by using an analogy to optical anti-reflection coating. In optics, it is well known that a stack of alternating layers of two dielectric materials can function as a highly transmissive or reflective filter for wide range of wavelength. Since electrons also have wave character as light, it would be possible to make an electronic analog of an optical filter. We demonstrate that alternating layers of two materials with different g-factors can function as a spin filter that allows electrons to be transmitted only when their spins point towards a certain particular direction. This spin-superlattice-based spin filter operates in wide energy ranges, curing the problem in the previous proposal.

• Human Ecology Research
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• v.55 no.6
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• pp.661-673
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• 2017

This study analyzes the current wearing status and awareness of warning clothing for elementary school students as well as to identify points of improvement for traffic accident prevention and clothing safety education. A survey was conducted on 279 elementary $5^{th}$ and $6^{th}$ graders in the Incheon area and Ansan in 2017 June & July. The results showed that more than 2/3 of participants had no experience wearing warning clothing. Second, 63% of participants answered 'traffic accident prevention' as the main purpose of warning clothing, showing that about 2/3 are aware of the importance. Third, yellow was the most preferred color of fluorescent material for warning clothing with a significant difference of preference by grade. The favorite color combination of participants was yellow & orange followed by yellow & light green, but showed a significant difference between boys and girls. Fourth, the most preferred form of warning clothing was fluorescent short sleeves and shorts without reflective tape, suggesting that students paid more to the purpose for reflective tape. Fifth, while 68% of participants were negative towards wearing safety clothes that are currently available, 66% were willing to try safety clothes if the color and the design improved. The results suggest an improved education with more emphasis on the purpose of clothing safety. Color and design adjustment of the current warning clothing is also recommended for a more active participation by elementary school students.

• Journal of the Korean Vacuum Society
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• v.19 no.2
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• pp.148-154
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• 2010

We have fabricated $SiO_2$ oxidation thin films by TCP-CVD (transformer coupled plasma chemical vapor deposition) method for passivation layer of OLED (organic light emitting diode). The purpose of this paper is to control and estimate the deposition rate and refracive index characteristics with process parameters. They are power, gas condition, distance of source and substrate and process temperature. The results show that transmittance of thin films is over 90%, rapid deposition rate and stable reflective index from 1.4 to 1.5 at controled process conditions. They are $SiH_4$ : $O_2$ = 30 : 60 [sccm] gas condition, 70 [mm] distance of source and substrate, no-biased substrate and under 80 [$^{\circ}C$] process temperature.

• Journal of the Korean institute of surface engineering
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• v.50 no.5
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• pp.345-351
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• 2017

A double-layered anti-reflective coating with hydrophilic/abrasion-resistant properties was studied using anatase titanium dioxide($TiO_2$) and silicon oxycarbide($SiO_xC_y$) thin film. $TiO_2$ and $SiO_xC_y$ thin films were sequentially deposited on a glass substrate by DC sputtering and PECVD, respectively. The optical properties were measured by UV-Vis-NIR spectrophotometer. The abrasion-resistance and the hydrophilicity were observed by a taber abrasion tester and a contact angle analyzer, respectively. The $TiO_2/SiO_xC_y$ double-layer thin film had an average transmittance of 91.3%, which was improved by 10% in the visible light region (400 to 800 nm) than that of the $TiO_2$ single-layer thin film. The contact angle of $TiO_2/SiO_xC_y$ film was $6.9^{\circ}$ right after UV exposure. After 9 days from the exposure, the contact angle was $10.2^{\circ}$, which was $33^{\circ}$ lower than that of the $TiO_2$ single-layer film. By the abrasion test, $SiO_xC_y$ film showed a superior abrasion-resistance to the $TiO_2$ film. Consequently, the $TiO_2/SiO_xC_y$ double-layer film has achieved superior anti-reflection, hydrophilicity, and abrasion resistance over the $TiO_2$ or $SiO_xC_y$ single-layer film.