• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.188-193
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• 2020

In this paper, we examine whether the 3D image experience through a light-field display device showed the difference in the arousal of the user compared with the 2D image experience. For our experiment, the Looking Glass^TM (LG) was used as a lightfield display device that provided 3D images, and 2D images were provided by digital and printed images. The subject's facial behavior during each media experience was recorded for analysis and the degree of arousal was measured by FaceReader^TM. As a result, the first image presented in the first order among the three kinds of images showed that there was a statistical difference in the degree of arousal between the three media. However, no significant differences were found between the three media in the other images. This may be because the arousal did not increase from the experience of the second image through the LG, owing to habituation. In conclusion, the 3D imaging experience may appear in the beginning, but does not continue.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.4
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• pp.139-143
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• 2005

For application of carbon nano-tube (CNT) as a counter electrode materials of dye-sensitized solar cell (DSSC), the electrochemical behavior of CNT electrode was studied, employing cyclic-voltammetry (C-V) and impedance spectroscopy. Fabrication of CNT-paste and formation of CNT-counter electrode for characteristic measurement have been carried out using ball-milling and doctor blade process, respectively. Unit cell for measurements was assembled using Pt electrode, CNT electrode, and iodine-embedded electrolyte. Field emission-scanning electron microscopy (FE-SEM) was used for structural investigation of CNT powder and electrode. Sheet resistance of electrode was measured with 4-point probe method. Electrochemical properties of electrode, C-V and impedance spectrum, were studied, employing potentiogalvanostat (EG&G 273A) and lock in amplifier (EG&G 5210). As a results, the sheet resistance of CNT electrode is almost similar to that of F-doped SnO2 (FTO) coated glass substrate as approximately 10 ohm/sq. From C-V and impedance spectroscopy measurements, it was found that CNT electrode has high reaction rate and low interface reaction resistance between CNT surface and electrolyte. These results provides that CNT electrode were superior to that of conventional Pt electrode. Particularly, the reaction rate in the CNT electrode is about thrice high than Pt electrode. Therefore. CNT electrode is to be good candidate material for counter electrode in DSSC.

• Journal of the Korean Ceramic Society
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• v.34 no.5
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• pp.483-490
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• 1997

Al2O3/metal composites were fabricated by oxidation and reaction of molten Al-alloy into two types of commercial Al2O3-SiO2 fibrous insulation board. The growth rate, composition and microstructure of these materials were described. An AlZnMg(7075) alloy was selected as a parent alloy. Mixed polycrystalline fiber and glass phase fiber were used as a filler. The growth surface of an alloy was covered with and without SiO2. SiO2 powder was employed as a surface dopant to aid initial oxidation of Al-alloy. Al-alloy, SiO2, fiber block and growth inhibitor CaSiO3 were packed sequentially in a alumina crucible and oxidized in air at temperature range 90$0^{\circ}C$ to 120$0^{\circ}C$. The growth rate of composite layer was calculated by measuring the mass increasement(g) per unit surface($\textrm{cm}^2$). XRD and optical microscope were used to investigate the composition and phase of composites. The composite grown at 120$0^{\circ}C$ and with SiO2 dopant showed rapid growth rate. The growth behavior differed a little depending on the types of fiber used. The composites consist of $\alpha$-Al2O3, Al, Si and pore. The composite grown at 100$0^{\circ}C$ exhibited better microstructure compared to that grown at 120$0^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.938-942
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• 2008

Electrical and optical properties of semitransparent Ag and Al layer were studied, which are used for the electrodes in top-emission organic light-emitting diodes. Sheet resistance and transmittance of visible light through a thin layer were measured and analyzed. Several thin metal layers of Ag and Al were deposited onto a glass substrate up to a thickness of 50 nm using a thermal evaporation. Sheet resistance measurements show that a layer thickness is needed more than 15 nm and 20 nm for Ag and Al, respectively, when a proper sheet resistance is assumed to be less than $50{\Omega}/sq$. From the measurements of transmittance of visible light through a thin-metal layer, metallic behavior was observed when the layer thickness is over 25 nm for both films. Thus, from a study of sheet resistance and transmittance of visible light, a minimum proper thickness of semitransparent metal layer is 20 nm and 25 nm for Ag and Al, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.264-265
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• 2008

While the reliability of bulk insulation has become important particularly in multilayer boards and embedded boards, electronics are to be used under various environments such as at high temperature and in high humidity. We observed internal space charge behavior for two types of epoxy composites under dc electric fields to investigate the influence of water at high temperature. In the case of glass/epoxy specimen, homocharge is observed at water-treated specimen, and spatial oscillations become clearer in the water-treated specimens. Electric field in the vicinity of the electrodes shows the injection of homocharge. In aramid/epoxy specimens, heterocharge is observed at water-treated specimens, i.e. negative charge accumulates near the anode, while positive charge accumulates near the cathode. Electric field is enhanced just before each electrode. In order to further examine the mechanism of space charge formation, we have developed a new system that allows in situ space charge observation during ion migration tests at high temperature and high humidity. Using this in situ system.

• Composites Research
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• v.28 no.3
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• pp.99-103
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• 2015

This paper presents the cure kinetics studies on the cure reaction of thermosetting resin. Above all, change in degree of cure and specific heat capacity according to temperature are observed using DSC and MDSC. The results are analyzed by cure kinetics and specific heat capacity model. Glass transition temperature was also measured to apply to the specific heat capacity model. Model parameters were gained from the modeling result. As a result, behavior of specific heat capacity can be calculated mathematically.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.5
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• pp.725-730
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• 1987

An experimental study of the air flow through inlet pipe of reciprocating two-cycle engine was investigated under motored condition. Measurements of the two components of velocity, velocity fluctuation, and the other behavior of inlet flow have been obtained by laser Doppler anemometer system. The research engine comprised the cylinder head of a two-cycle engine which mounted on optical spacer with measuring window and glass inlet entry for laser anemometer measurement. A dual beam laser Doppler anemometer was used with conventional forward scattered method and comprised argon-ion laser, frequency shifter with Bragg cell module, and the signal processor. Measurements of mean velocity fluctuation of inlet flow for different engine speeds, measuring positions, and the changes in cylinder volume are investigated. The results presented show that the changes in engine speed is shown to be strongly influenced on the mean velocity of inlet air. The effect of measuring position and cylinder volume on the inlet velocity was also investigated for the inlet port entry and is shown to be small compared to the engine speed.

• Journal of Mechanical Science and Technology
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• v.16 no.1
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• pp.39-45
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• 2002

Initiation and propagation of interfacial crack along bimaterial interface are considered in this study. A biaxial loading device for a single specimen is used for obtaining a wide range of mode-mixities. The specimen is an edge-cracked bimaterial strip of glass and epoxy; the biaxial loading device, being capable of controlling displacements in two perpendicular directions, is developed. A series of interfacial crack initiation and Propagation experiments are conducted using the biaxial loading device for various mixed modes. Normal crack opening displacement (NCOD) is measured near crack front by a crack opening interferometry and used for extracting fracture parameters. From mixed mode interfacial crack initiation experiments, large increase in toughness with shear components is observed. The behavior of interfacial crack propagation analyzed as a function of mode-mix shows that initial crack propagation is delayed with increase of mode-mixity, and its velocity is increased with positive mode-mixity but decreased with negative case. However, it is found that crack propagation is less accelerated with positive mode-mixity than the negative mode-mixity, which may be caused by contact and/or effects of friction between far field and near-tip Held along the interfacial crack.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.3
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• pp.9-17
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• 2003

In this paper, thermo-mechanical and rheological properties of NCPs (Non-Conductive Pastes) depending on silica filler contents and diluent contents were investigated. And then, thermal cycling (T/C) reliability of flip chip assembly using selected NCPs was verified. As the silica filler content increased, thermo-mechanical properties of NCPs were changed. The higher the silica filler content was added, glass transition temperature ($T_g$) and storage modulus at room temperature became higher. While, coefficient of thermal expansion (CTE) decreased. On the other hand, rheological properties of NCPs were significantly affected by diluent content. As the diluent content increased, viscosity of NCP decreased and thixotropic index increased. However, the addition of diluent deteriorated thermo-mechanical properties such as modulus, CTE, and $T_g$. Based on these results, three candidates of NCPs with various silica filler and diluent contents were selected as adhesives for reliability test of flip chip assemblies. T/C reliability test was performed by measuring changes of NCP bump connection resistance. Results showed that flip chip assembly using NCP with lower CTE and higher modulus exhibited better T/C reliability behavior because of reduced shear strain in NCP adhesive layer.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.302-305
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• 2002

Scoria is a bomb-sized, generally vesicular pyroclast that is red or black in color and light in weight. In this study, scoria from Cheju was examined for the use as a sorbent. It is composed of plagioclase, olivine, hornblende, pyroxene, and glass, with an average composition of 49.84% SiO$_2$, 14.07% A1$_2$O$_3$, End 9.14% Fe$_2$O$_3$. Studies on kinetic isotherm sorption of Zn(II) onto scoria under various parameters such as initial zinc concentration, particle size, and adsorbent/adsorbate ratio were carried out using an agitated batch. The results suggest that the smaller scoria size and the larger adsorbent/adsorbate ratio produce the higher degree of Zn(II) removal. More effective removal also appears at lower initial Zn concentration. The sorption behavior of Zn(II) onto scoria seems to be mainly controlled by cation exchange. Studies on equilibrium isotherm sorption of other heavy metals (Pb, Cu, Cd) onto scoria were also conducted and compared with those onto powdered activated carbon (PAC) and non-organic matter scoria (NOS), The results suggest that the Cheju scoria has the slightly higher sorption capability than PAC and NOS, and the order of the effective sorption onto scoria and PAC is Pb > Cu > Zn > Cd. The monometal sorption onto scoria is more stronger than the competitive sorption.