• Journal of Digital Contents Society
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• v.11 no.3
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• pp.315-322
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• 2010

This study focused on mobile trend in diffusion of smart phone. Presently, it has been evolved from digital nomad to smart nomad. Smart nomad era is based on digital technology with mobility and being smart. Smart nomad that is made up high-end device and intellectual content has changed structure of industry and life style. Smart phone is a core key in smart nomad era. In 2010 smart phone has been distributed about 2.5 hundreds million which is 20% of whole mobile phone sales and the volume of smart phone sales will be getting bigger and bigger in near future. Although, there are various reasons for success of smart phone market, this research focused 4 reasons: first, development of mobile device, second, evolution of mobile content distribution, third, support of government system, fourth, success of Docomo i-mode and Apple i phone. Smart phone will grow up more rapidly. Smart phone eco-system will be more competitive in the world. In Korea, smart phone eco-system also will be very competitive. For success in the middle of this competitive environment, Korea should lead the competitive phase with development of ability of creation software and content, construction of various partnership and evolution of next generation technology and service.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.857-870
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• 2007

The structure and evolution of a thunderstorm outflow in two dimensions with no environmental wind are investigated using a cloud-resolving model with explicit liquid-ice phase microphysical processes (ARPS: Advanced Regional Prediction System). The turbulence structure of the outflow is explicitly resolved with a high-resolution grid size of 50m. The simulated single-cell storm and its associated Kelvin-Helmholtz (KH) billows are found to have the lift stages of development maturity, and decay. The secondary pulsation and splitting of convective cells resulted from interactions between cloud dynamics and microphysics are observed. The cooled downdrafts caused by the evaporation of rain and hail in the relatively dry lower atmosphere result in thunderstorm cold-air outflow. The outflow head propagates with almost constant speed. The KH billows formed by the KH instability cause turbulence mixing from the top of the outflow and control the structure of the outflow. Ihe KH billows are initiated at the outflow head, and pow and decay as moving rearward relative to the gust front. The numerical simulation results of the ratio of the horizontal wavelength of the fastest growing perturbation to the critical shear-layer depth and the ratio of the horizontal wavelength of the billow to its maximum amplitude are matched well with the results of other studies.

• Korean Journal of Materials Research
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• v.13 no.9
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• pp.572-580
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• 2003

Synthesizing behavior and microstructural evolution of $CaZrO_3$and $m-ZrO_2$in a thermal reaction process of $ZrSiO_4$-$xCaCO_3$mixtures, where x is 7 and 19, were investigated to determine the addition amount of CaO in CaO:$ZrO_2$:$SiO_2$ternary composition. CaZrO$_3$-Ca$_2$SiO$_4$precursor prepared by the mixture of $ZrSiO_4$and CaCO$_3$in aqueous suspending media was controlled to the acidic (pH=4.0) condition with HCI solution to enhance the thermal reaction. The addition amount of dispersant into the $ZrSiO_4$-$xCaCO_3$slip increased with increasing mole ratio of $CaCO_3$, which was associated with the viscosity of slip. Decarbonation reaction was activated with an increase of the addition amount of $CaCO_3$, showing different final temperatures in $ZrSiO_4$-$7CaCO_3$and $ZrSiO_4$-$19CaCO_3$mixtures as about 980 and 116$0^{\circ}C$, respectively, for finishing decarbonation reaction. The grain morphology was changed to spherical shape for all samples with an increase of sintering temperature. The grain size and phase composition of the synthesized composites depended on the mixture ratio of Zrsi04 and CacO3 powders, indicating that the main crystals were m-ZrO2 ($\leq$3 $\mu\textrm{m}$) and $CaZrO_3$ ($\leq$ 7 $\mu\textrm{m}$) in $ZrSiO_4$$>-7CaCO_3$and $ZrSiO_4$-$19CaCO_3$mixtures, respectively.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.54-61
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• 1995

In order to investigate the effects of Ganoderma lucidum on the fermentation of media by Kluyveromyces fragilis KCCM 35458, with 0%, 0.1%, 0.5%, and 1.0% (w/v) of Ganoderma lucidum extract were added to skin milk and fermented in the suspension culture at $30^{\circ}C$ for 72 hours. The pH, acidity, $CO_2$ evolution, alcohol production, number of yeast cells and lactose content were investigated. The results are summarized as follows; 1. As fermentation time advanced by the pH was decreased and the acidity was increased in the media of 1.0% Gnaoderma lucidum extract as fermentation time advanced. 2. $CO_2$ evolution was increased in the all of Genoderma lucidum extract and significantly effect showed in 1.0% extract medium. 3. During 72 hours culturing, alcohol was detected in all Gandoderma lucidum extract media, 1.0% Ganoderma lucidum extract medium showed extremly high in alcohol and shortened fermentation time. 4. The number of yeast was increased more at logarithmic phase and the growth of yeast was more rapid in all Ganoderma lucidum extract especially 0.5%, 1.0% media samples than control. 5. As fermentation time goes by, the lactose content of media were decreased more rapidly in 1.0% Ganoderma lucidum extract medium than control.

• 대한공업교육학회지
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• v.31 no.2
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• pp.155-176
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• 2006

The purpose of this study was to explore the strategies for applying TRIZ to technology education. This study was carried out through literature review on contradiction, 40 principles, 76 standard solutions, multi screen method, effects, the law of technology evolution, and ARIZ, and questionnaire survey to investigate the validity. Through this study the strategies for applying TRIZ to technology education were proposed and the validity was identified. Only the '40 Principles' was appropriate to technology education of elementary and middle school. The results of this study were as follows; In elementary school technology education, segmentation, extraction, local quality, asymmetry, consolidation, universality, counterweight, do it in reverse, mediator, self service, dispose, flexible membranes or thin films, changing the color, homogeneity, rejecting and regenerating parts, and composite materials were suitable. And in middle school technology education, segmentation, extraction, local quality, asymmetry, consolidation, universality, counterweight, prior counteraction, prior action, cushion in advance, do it in reverse, dynamicity, partial or excessive action, continuity of useful action, convert harm into benefit, mediator, self service, dispose, flexible membranes or thin films, changing the color, homogeneity, rejecting and regenerating parts, transformation of properties, phase transition, thermal expansion, and composite materials were suitable.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.57.4-58
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• 2021

Asteroids have undergone various processes such as impacts, space weathering, and thermal evolution. Because they expose their surfaces to space without atmosphere, these evolutional processes have been recorded directly on their surfaces. The remote-sensing observations have been conducted to reveal these evolutional histories of the target asteroids. For example, crater and boulder distributions are unambiguous evidence for past nondestructive impacts with other celestial bodies. Multiband and spectroscopic observations have revealed space-weathering history (as well as compositions). Whereas most physical quantities have been examined intensively using spacecraft and telescopes, only a little has been studied on "the grain size". It is one of the fundamental physical quantities for diagnosing the collisional and thermal history of asteroids. Our group has conducted polarimetric research of asteroids (as well as Moon [1]) to determine the particle size and further investigate the evolutional histories of target asteroids [2],[3]. For example, the existence of regolith on an S-type asteroid, Toutatis, was suggested almost twenty years before space exploration [4]. Moreover, we reported that near-Sun asteroids indicate a signature of submillimeter grains, which could be created by a thermal sintering process by solar radiation [5]. However, it is important to note that in-situ polarimetry has not been reported on the asteroid surface, although the Korean Lunar Exploration Program aims to do polarimetry on the lunar surface [6]. Therefore, it is expected that the polarizer mounted on the Korean Apophis spacecraft can make the first estimate of the grain size and its regional variation over the Apophis surface. In this presentation, we outline research of S-type asteroid surfaces through remote-sensing observations and consider the role of polarimetry. Based on this review, we consider the purpose, potentiality, and strategy of the polarimetry using the onboard device for the Apophis spacecraft. We will report a possible polarization phase curve of Apophis estimated from ordinary chondrites and past observational data of S-type asteroids, taking account of the space weathering effect. Based on this estimation, we will consider the strategy of how to determine the particle size (and space weathering degree) of the Apophis surface. We will also mention the detectability of dust hovering on the surface.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.37-46
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• 2024

This study investigates the evolution of concrete damage due to chloride-induced steel corrosion through Impact-echo (IE) testing. Three reinforced concrete specimens, each measuring 1500 mm in length, 400 mm in width, and 200 mm in thickness, were fabricated using three concrete mixture proportions of blended cement types: ordinary Portland cement, ground granulated blast-furnace slag and fly ash. Steel corrosion in the concrete was accelerated by impressing a 0.5 A current following a 35-day cycle of wet-and-dry saturation in a 3% NaCl solution. Initial IE data collected during the saturation phase showed no significant changes, indicating that moisture had a minimal impact on IE signals and highlighting the slow progress of corrosion under natural conditions. Post-application of current, however, there was a noticeable decline in both IE peak frequency and the P-wave velocity in the concrete as the duration of the impressed current increased. Remarkably, progressive monitoring of IE proves highly effective in capturing the critical features of steel-corrosion induced concrete deterioration, such as the onset of internal damages and the rate of damage propagation. These results demonstrate the potential of progressive IE data monitoring to enhance the reliability of diagnosing and prognosticating the evolution of concrete damage in marine environment.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.132-140
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• 2007

The phase-shift method and correlation constants for studying a linear relationship between the behavior ($-{\varphi}\;vs.\;E$) of the phase shift ($0^{\circ}{\leq}-{\varphi}{\leq}90^{\circ}$) for the optimum intermediate frequency and that (${\theta}\;vs.\;E$) of the fractional surface coverage ($1{\geq}\theta{\geq}0$) have been proposed and verified to determine the Langmuir, Frumkin, and Temkin adsorption isotherms (${\theta}\;vs.\;E$) at noble metal/aqueous electrolyte interfaces. At an Ir/0.1 M KOH aqueous electrolyte interface, the Langmuir and Temkin adsorption isotherms (${\theta}\;vs.\;E$), equilibrium constants ($K=3.3{\times}10^{-4}\;mol^{-1}$ for the Langmuir and $K=3.3{\times}10^{-3}{\exp}(-4.6{\theta})\;mol^{-1}$ for the Temkin adsorption isotherm), interaction parameter (g = 4.6 for the Temkin adsorption isotherm), and standard free energies (${\Delta}G_{ads}^0=19.9kJ\;mol^{-1}\;for\;K=3.3{\times}10^{-4}\;mol^{-1}$ and $16.5<{\Delta}G_{\theta}^0<23.3\;kJ\;mol^{-1}\;for\;K=3.3{\times}10^{-3}{\exp}(-4.6{\theta})\;mol^{-1}\;and\;0.2<\theta<0.8$) of H for the cathodic $H_2$ evolution reaction are determined using the phase-shift method and correlation constants. The inhomogeneous and lateral interaction effects on the adsorption of H are negligible. At the intermediate values of ${\theta},\;i.e,\;0.2<{\theta}<0.8$, the Temkin adsorption isotherm (${\theta}\;vs.\;E$) correlating with the Langmuir or the Frumkin adsorption isotherm (${\theta}\;vs.\;E$), and vice versa, is readily determined using the correlation constants. The phase-shift method and correlation constants are accurate and reliable techniques to determine the adsorption isotherms (${\theta}\;vs.\;E$) and related electrode kinetic and thermodynamic parameters(K, g, ${\Delta}G_{ads}^0, {\Delta}G_{\theta}^0$).

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.323-329
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• 2009

Influences of ceramic filler types and dose on the sintering, phase evolution, and dielectric properties of ceramic/CaO-$Al_2O_3-SiO_2$ glass composites were investigated. All of the specimens were sintered at $900^{\circ}C$ for 2 h, which conditions are required by the lowtemperature co-firing ceramic (LTCC) technology. Ceramic fillers of $Al_2O_3,\;SiO_2$, kaolin, and wollastonite were used. The addition of $Al_2O_3$ filler yielded the crystalline phases of alumina and wollastonite, and the densification over 95% of the relative density was achieved up to 50 wt% addition of the filler. For the cases of the fillers of $SiO_2$, kaolin, and wollastonite, crystalline phases of quartz, mullite, and wollastonite formed, while the densification decreased monotonically with the filler addition. In overall, all the investigated fillers with 10 wt% addition resulted in a reasonable sintering (over 95 %) and low dielectric constants (less than 6), demonstrating the feasibility of the investigated composites for application to a LTCC substrate material with a low dielectric constant.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.5
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• pp.401-408
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• 2013

Dual-layer differential codebook using 8-PSK (phase shift keying) constellation as its codeword elements, is proposed for Long term evolution (LTE) and/or LTE-Advanced systems. Due to the temporal correlation of the adjacent channel matrices, the consecutive precoding matrices are likely to be similar. This approach quantize only the differential information of the channel instead of the whole channel subspace, which virtually increase the codebook size to realize more accurate quantization of the channel. Especially, the proposed codebook has the same properties of LTE release-8 codebook that is, constant modulus, complexity reduction, and nested property. The mobile station can be designed by using less expensive non-linear amplifier utilizing constant modulus property. Computer simulations show that the capacity of the proposed dual-layer codebook performs almost 1.2dB better than those of any other non-differential codebooks with the same amount of feedback information.