• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2262-2267
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• 2010

In order to analyze the reason of wall blackening, which affect the decline of lifetime in a ceramic metal halide lamp, we carried out the deterioration of ceramic tubes by a change in operating conditions with arc tubes of two types of spherical and cylindrical, and we have confirmed the cause of wall blackening through the analysis of element composition and spectrum from SEM/EDS and spectrum analyzer. Wall blackening of tungsten was shown by sputtering from ignition in 20 minute on/off condition and wall blackening from chemical reaction between PCA wall and rare earth halides was shown significantly in a condition without on/off test. Especially, the wall blackening and the decline of luminous flux were reduced by inner convection in spherical type arc tube. Moreover, the color temperature and color coordinate were changed by reduction of emission spectrum of Dy which causes the chemical reaction with PCA wall.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.271-274
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• 1999

In this paper, we studied the matrix type Powder AC Electroluminescence using ZnS:Cu,Cl Phosphor. Previously, Powder AC EL was used in Backlighting of LCD. Rescently, organic Thin Film EL was rapidly developed because of high Luminescence and low applied voltage. But Powder AC EL has Superior features that include sheet like flexibility thickness, low weight, self-emission, a wide viewing angle and a fast response time. We tried to change of phosphor thickness and binder mixture rate in order to obtain the good condition of powder AC EL and we obtained the very low breakdown voltage that was just 15V. Till now, we measured the current-voltage(V-I), luminance-voltage(V-L), Luminance-current (L-I), color coordinate (CIE), and phosphor Intensity of variable thickness. In experiment result, the devices has the luminance of 840 cd/$m^2$ and improved color coordinate, x=0.1557, y=0.2145, using a 10kHz drive frequency.

• Journal of the Korea Fashion and Costume Design Association
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• v.25 no.2
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• pp.135-150
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• 2023

The purpose of this study is to understand the formative characteristics of futuristic virtual fashion revealed in virtual fashion platforms targeting the human body. First, the current status of fashion in the metaverse and futurist fashion were reviewed and summarized by referring to prior research. Next, among the items posted on DRESSX, "futurism" was searched and those resturning a positive result were collected as research subjects. The characteristics were organized into design elements: colors, shapes, materials, and patterns. Futuristic aesthetic characteristics were derived from the characteristics of each design element. As a result, color showed the characteristics of achromatic, vivid and neon colors, multi-color and gradation, multi-color due to reflected light, and color conversion. As for the form, a body-concious look or exaggerated silhouettes, spatial expressions in geometric structures, forms imitating living things, and fluid silhouettes using clouds were prominent. Materials showed the digitization of universal clothing materials, application of industrial materials, use of metal materials, and unrealistic materials. In the patterns, geometric abstract patterns, patterns that reveal the digital world view, and moving fluid patterns appeared. The aesthetic characteristics of futurism in virtual fashion were revealed in four categories: visual dynamics, high-tech sensibility, variability, kineticisim. Visual dynamics were revealed in geometric forms, and intense neon colors. High-tech sensibility was prominent in the use of metal and industrial materials, light emission, and patterns of the digital world view. The expression of multiple colors by reflected light and the change showed the variability of futurism. The use of unrealistic materials, such as clouds and fire and fluid silhouettes expressed kineticisim. The infinite expressiveness of virtual fashion made it possible to actively express the aesthetic characteristics of futurism.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.23-24
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• 2003

We synthesized a poly[2-(2'-hydroxyphenyl) benzoxazole] under the two step procedures of Suzuki coupling polymerization with corresponding monomers followed by the deprotection of benzyl group. The polymer in DMF solution is applicable to colorimetric sensing fluoride anion, which shows a color change from colorless to yellow. High sensitivity to fluoride anion compared to other anions such as phosphate, chloride, and sulfate is ascribed to the high coordination ability of the 2-(2'-hydroxy phenyl)benzoxazole moiety in the polymer chain. Emission shift by metal cations, which can be applied to fluorescent sensing w as also observed in the polymer solution.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1440-1442
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• 2007

In this work, we have modeled and fabricated microcavity-enhanced OLED using the 1-dimensional distributed Bragg reflector model (DBR). Results show that simulated spectrum intensity of microcavity OLED increased more than 30% compared to the conventional OLED, by use of DBR with $TiO_2$ and $SiO_2$. Spectral change of green and blue emission was expected to give the deeper color. The experimental design and characterization as well as the matching with simulated properties were performed for microcavity OLED for actual application.

• Macromolecular Research
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• v.9 no.2
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• pp.116-121
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• 2001

A series of poly(1,4-phenylenevinylene-alt-3-alkyl-2,5-thienylenevinylene)s (alkyl = hexyl [PPV-alt-6-TV] and octyl (PPV-alt-8-TV] group) have been synthesized by the Heck coupling reaction. These polymers were characterized using $^1$H-NMR, FT-IR spectroscopy, and thermogravimetric analysis (TCA). They are solvent processible and have obviously copolymeric structure. The photophysical properties of the polymers were investigated using UV-visible and steady-state photoluminescence(PL) spectroscopy. We studied the change of light-emitting properties by incorporating the thiophene group into the PPV polymer backbone using alternating copolymer system. The properties of two synthesized polymers are very similar, but they exhibited apparent changes of light-emitting properties compared with other PPV backbone based polymers. The broad absorption bands from 350 to 570 nm are due to $\pi$-$\pi$* transitions of the polyconjugated systems. The absorption maxima of the two polymers were found at about 452 and 448 nm for PPV-alt-6-TV and PPV-alt-8-TV, respectively. The copolymers showed broad PL spectra between 550 and 700 nm without vibronic bands and PL emission maxima of PPV-alt-6-TV and PPV-alt-8-TV are about 620 and 605 nm, respectively. The copolymers exhibited the red emission (PPValt-6-TV), but more red shifted emissions are needed to obtain real red color.

• Korean Journal of Optics and Photonics
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• v.32 no.5
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• pp.220-229
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• 2021

The optical characteristics of high-power direct-lit white light-emitting diode (LED) lighting were investigated, where a quantum dot (QD) film was adopted to enhance the color-rendering index (CRI). The transmittance of the diffuser plate and the concentration of the QD film were varied in this study. The color coordinates and the correlated color temperature (CCT) did not show any appreciable change, while the CRI values increased slightly as the transmittance of the diffuser plate decreased. The investigated optical properties were nearly independent of the viewing angle, and the luminance distribution was close to Lambertian. The CCT decreased from approximately 6000 K to approximately 4000 K as the concentration of the QD film increased from 0 to 7.5 wt%, which was due to the enhanced red component in the emission spectrum. The CRI increased to approximately 95 for some optical configurations of the lighting. These results demonstrate that glare-free, color-changeable, high-rendering LED lighting can be realized by using a combination of a diffuser plate of appropriate transmittance and a red QD film.

• Journal of the Korean Applied Science and Technology
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• v.23 no.3
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• pp.243-251
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• 2006

Field emission display(FED) is actively investigated in view of the development of full color flat-panel display, which can replace some cathode-ray tube(CRT). Thus, the development of new phosphors appropriate for FED is urgently needed and has been actively investigated. In this work, $SrTiO_3:Pr^{3+}$ phosphor was prepared by sol-gel method and the coating was applied by sol-gel method combined with sonication on these phosphor's surface into diluted precursor solution. It was found that very fine particles of coating material were formed on phosphor's surface. The luminescent intensity of $SrTiO_3:Pr^{3+}$ phosphor coated with $SiO_2$ and $Al_2O_3$ was considerably increased without any noticeable change in color chromaticity. The optimum concentration of coating material was found to be 1wt% and the optimum pH value of the solution was 10.

• Korean Journal of Optics and Photonics
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• v.26 no.3
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• pp.139-146
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• 2015

The effects of a dielectric multilayer mirror on the efficiency of organic light-emitting diodes (OLEDs) were investigated by using optical simulation. Adoption of a dielectric mirror consisting of alternating SiN and $SiO_2$ layers narrowed the emission spectrum due to the microcavity effect, and increased the outcoupling efficiency by a few percent. The layer thicknesses of the dielectric mirror were adjusted to change the wavelength of the resonance mode, which may be used to increase the color purity.

• Applied Microscopy
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• v.42 no.3
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• pp.129-135
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• 2012

In this study, the changes in hair quality before and after Magic straight perm have been evaluated through a hair damage measurement method. For this, a healthy high school student's (age18 years) wavy hair was selected and permed on the left and right sides. Then, the changes caused by physical methods which were applied during the fl at iron-based Magic straight perm were evaluated based on the hair damage measurement method before and after the Magic straight perm. According to the protein release test after the Magic straight perm, 1.26% in average and 0.14% was observed in Cool Magic straight perm sample. In a field emission scanning electron microscopy (FE-SEM) test, saw teeth-shaped partial desquamation of cuticle cells and impurities were observed in the warm-treated hair sample. In atomic force microscope (AFM), line-profile is a method to represent roughness data on hair. According to analysis on 3-dimensional (3D) images, the hair with Cool Magic straight perm was lower than the hair with Warm Magic perm in terms of the color change of 3D images. In addition, vertical changes were observed in the hair with Cool Magic perm. As a result, irregular surface roughness was observed. This study proposed a method to minimize hair damage by cooling down the heat with the cool hair straightener as soon as the Warm Magic was finished.