• Proceedings of the PSK Conference
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• 2005.11a
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• pp.221-221
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• 2005

• Corrosion Science and Technology
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• v.12 no.1
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• pp.1-6
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• 2013

Recently Digital TV industry has drastically been moving the illuminating system, which causes an obvious product change from PDP and LCD to LED model to provide high-definition image. Due to strong competition in the digital industry, TV manufacturers make a great efforts to reduce production cost by using low-priced materials such as steels instead of aluminum and plastic etc. In this paper we have developed a new low-priced electrogalvanized steel sheet, which has a black resin composite layer, to substitute conventional high-priced PCM steel and plastic mold for rear cover panel in the digital TV. The black resin composite was prepared by mechanical dispersion of the mixture solution that consists of high solid polyester resin, melamine hardener, black pigment, micronized silica paste, polyacrylate texturing particle and miscellaneous additives. The composite solution was coated on the steel sheet using roll coater followed by induction furnace curing and cooling. Although the coated layer has a half thickness compared to the conventional PCM steels having $23{\mu}m$ thickness, it exhibits excellent quality for the usage of rear cover panel. The new steel sheet was applied to test products to get quality certification from worldwide electronic appliance customers. Detailed discussion provides in this paper including preparation of composite solution, roll coating technology, induction curing technology and quality evaluation from customers.

• Molecules and Cells
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• v.38 no.5
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• pp.409-415
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• 2015

Low-barrier hydrogen bonds (LBHBs) have been proposed to have important influences on the enormous reaction rate increases achieved by many enzymes. ${\Delta}^5$-3-ketosteroi isomerase (KSI) catalyzes the allylic isomerization of ${\Delta}^5$-3-ketosteroid to its conjugated ${\Delta}^4$-isomers at a rate that approache the diffusion limit. Tyr14, a catalytic residue of KSI, has been hypothesized to form an LBHB with the oxyanion of a dienolate steroid intermediate generated during the catalysis. The unusual chemical shift of a proton at 16.8 ppm in the nuclear magnetic resonance spectrum has been attributed to an LBHB between Tyr14 $O{\eta}$ and C3-O of equilenin an intermediate analogue, in the active site of D38N KSI. This shift in the spectrum was not observed in Y30F/Y55F/D38N and Y30F/Y55F/Y115F/D38N mutant KSIs when each mutant was complexed with equilenin, suggesting that Tyr14 could not form LBHB with the intermediate analogue in these mutant KSIs. The crystal structure of Y30F/Y55F/Y115F/D38N-equilenin complex revealed that the distance between Tyr14 $O{\eta}$ and C3-O of the bound steroi was within a direct hydrogen bond. The conversion of LBHB to an ordinary hydrogen bond in the mutant KSI reduced the binding affinity for the steroid inhibitors by a factor of 8.1-11. In addition, the absence of LBHB reduced the catalytic activity by only a factor of 1.7-2. These results suggest that the amount of stabilization energy of the reaction intermediate provided by LBHB is small compared with that provided by an ordinary hydrogen bond in KSI.

• Journal of Life Science
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• v.7 no.1
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• pp.17-23
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• 1997

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of maine pollutions by changes in cholinesterase activity of the flounder (Paralichthys olivaceus)in Yellow Sea of Korea. Acetylcholinesterase (AChE) activities in brain and muscle of cultured flounders in Yellow Sea were remarkably lower (40-50% and 40-55%, respectively)than those of wild flounder in Pohang (control) of East Sea, but AChE activities in brain and muscle of wild flounders in Yellow Sea were significantly lower(15-40% and 25-35%, respectively)than those of wild flounder in Pohang of East Sea. Butyrylcholinesterase(BChE) activities in barin and muscle of cultured flounders in Yellow Sea were remarkably lower(70-75% and 65-75%, respectively) than those of wild flounder in Pohang of East Sea, but BChE activities in barin and muscle of wild flounders in Yellow Sea were significantly lower (15-40%and 25-35%, respectively)than those of wild flounder in Pohang of East Sea. Lactate dehydrogenase (LDH) activities in serum of cultured flounders in Yellow Sea were significantly 10-50% higher than those of wild flounder in Pohang of East Sea, but LDH activities in serum of wild flounders in Yellow Sea were significantly 20-25% higher than those of wild flounder in Pohang of East Sea. It suggests that AChE and BChE activities in brain and muscle of cultured and wild flounders of Yellow Sea may be used as the most effective mean in a biochemical markers for diagnosis of pollutant effects by organophosphorus pesticides.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.601-608
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• 2014

The purpose of this study was to explore the long-term variability of sea surface temperature (SST) and cluster analysis derived from in-situ data in the coastal oceanographic observation 8 stations (Sokcho, Jumunjin, Donghae, Jukbyeon, Pohang, Janggigab, Ulgi, Gampo) of the East Sea during 1971-2013. As a result of cluster analysis, SST variations in each area could be divided into two groups, which was a group A of Sokcho, Jumunjin, Donghae, and group B of Jukbyeon, Pohang, Janggigab, Ulgi, Gampo. The SST and SST anomalies at Sokcho, Jukbyeon, Pohang and Gampo during 1971-2013 showed the increase-trend with the variations of decadal-scale. Annual SST values also increased remarkably after 1988. The increases of SST for 43 years showed $2.26^{\circ}C$ at Sokcho, $1.99^{\circ}C$ at Jukbyeon, $1.11^{\circ}C$ at Pohang and $0.89^{\circ}C$ at Gampo. In particular, the SST variations of the northern areas were higher than those of southern areas. The seasonal SSTs increased the order of Sokcho-Jukbyeon-Pohang-Gampo in fall and winter and that of Jukbyeon-Sokcho-Pohang-Gampo in spring and summer.

• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.34-35
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• 2005

• Current Applied Physics
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• v.18 no.11
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• pp.1185-1189
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• 2018

Thickness-dependent magnetic domain structure of ultrathin Co wedge films (0.3 nm-1.0 nm) sandwiched by Pt layers was investigated by scanning transmission x-ray microscopy (STXM) employing X-ray magnetic circular dichroism (XMCD), utilizing elliptically polarized soft x-rays and electromagnetic fields, with a spatial resolution of 50 nm. The magnetic domain images measured at the Co $L_3$ edge showed the evolution of the magnetic domain structures from maze-like form to the bubble-like form as the perpendicular magnetic field was applied. The asymmetric domain expansion of a 500 nm-scale bubble domain was also measured when the in-plane and perpendicular external magnetic field were applied simultaneously.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.957-962
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• 1998

As the first stage accelerator of the Korea Multipurpose Accelerator Complex (KOMAC) 1GeV proton linac, a 350MHZ, cw Radio-Frequency Quadrupole (RFQ) will be built to produce 20㎃ of 3Mev. High current RFQ with cw operation is a major program in the KOMAC project to understand beam dynamics, engineering design, construction, control and diagnostics techniques. The beam dynamics and the engineering design of RFQ are described and the present status of the KOMAC RFQ project is discussed.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.3
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• pp.149-160
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• 2018

This study experimentally and analytically examines the seismic vulnerability of steel rack storage frames subjected to Korea earthquakes (2016 Gyeongju earthquake and 2017 Pohang earthquake). To achieve this aim, this study selects a three-story, one-bay steel rack frame with a typical configuration of rack frame in Korea. Firstly, the local behavior for frame components is examined by performing monotonic and/or cyclic load tests and the global response and dynamic characteristics of the subject rack frame are investigated by conducting a shaking table test. The analytical model of the rack frame is then created based on the experimental results and is used to perform nonlinear time history analyses with recorded Korea earthquakes. The seismic demand of the rack frame is considerably affected by the spectral acceleration response, instead of peak ground accelerations (peak floor accelerations). Moreover, the collapse fragility curve of the rack frame is developed using incremental dynamic analyses for the Gyeongju and Pohang earthquakes. Fragility results indicate that the ground motion characteristics of these earthquakes do not significantly affect the frame vulnerability at the collapse state.

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.40-40
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• 1996