• Journal of Applied Reliability
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• v.15 no.3
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• pp.197-206
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• 2015

Failure analysis of pre-insulated pipe (SPPS 380, 400A) transporting high temperature water ($95{\sim}110^{\circ}C$) for a plant was carried out. The damaged area (${\Phi}5mm$) of pre-insulated pipe was found only on welds. The chemical composition of damaged pipe meets specification of carbon steel pipes for pressure service (KS D 3562). As results of microstructure analysis, crack propagated from outer to inside after pitting corrosion occurred on the outside surface. The non-metallic inclusion existed on the end of crack. And the non-metallic inclusion continuously and linearly formed along with the bond line of welds. Based on SEM-EDS analysis, the nonmetallic inclusions have higher Manganese (Mn) and Oxygen (O) content but sulfur (S) was not detected. As results of water quality analysis, hydrogen ion concentration and minerals like Fe, Mg, Si were in low level. But the content of dissolved oxygen (11.2 ppm) was slightly higher than that of standard. It seems that the cause of damaged pipe is grooving corrosion due to MnO inclusion formed on bond line and corrosion took place nearby welds.

• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.169-173
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• 2009

In this study, We were studied on the properties of polyurethane elastomer containing the polyol, chain extender and isocyanate in polyurethane elastomer. Polyurethane elastomer had the best properties with poly(tetramethylene) glycol for in-line skate wheel. With more incorporation of chain extender content in polyurethane elastomer, tensile strength and hardness increased and elongation decreased. And then properties of polyurethane elastomer with the bulky type isocyanate had better than the flexible type isocyanate.

• Research in Mathematical Education
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• v.11 no.3
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• pp.185-196
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• 2007

In order to study the new curriculum, as well as to help teachers understand new textbooks well, the authors make horizontal comparisons between Editions A and B of Experimental Mathematics (2) textbook in ordinary senior high schools (Grades 10-12) of PEP Edition, which focuses on the topic of line slope. The interview was made with 11 selected teachers who are teaching the content in the light of Edition B. It was found that there are obvious differences in the introduction of concepts and the exercises. The interviews showed that teachers were familiar to the contents of Edition A and saw it reasonable, because few differences are found between Edition A and the old Edition. The teachers also viewed that though the contents of Edition B were easy and fit to self-educated, but its reasoning is not clear, and the examples are not enough so that the teachers need to add additional examples.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.171-171
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• 2003

Asiaticoside, a biologically active triterpenoid present in Centella asicatica, has been known to exert a variety of biological effect such as wound-healing, hepatoprotective, anti-inflammatory. In this study, we observed the effect of asiatic acid asiaticoside and its 16 derivatives on the cytotoxicity and the content of hydroxyproline in rat hepatic stellate cell line, HSC-T6 cell as a preliminary study for screening the anti-hepatofibrotic effect.(omitted)

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.152-154
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• 2005

Austenitic stainless steel has good weldability but is sensitive to hot cracking such as solidification crack and liquation crack. In this study, the specimens of dissimilar metals made between austenitic stainless steel and Al-brass were welded by GTAW process using four different filler metals. Cracks were detected in the heat-affected zone of the stainless steel when welded with CuAl, CuSn and NiCu filler metals, but no cracks were detected a Ni filler metal was used. The cracks propagated along the grain boundary in the heat affected zone near the fusion line to base metal of 316L stainless steel. The cracks were located inside the weld bead with very fine hairline crack. All cracks initiated at the fusion line and moved forward in the base metal. From energy dispersion spectroscopy (EDS), Cu peak was detected only in the crack-opening area.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.988-990
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• 2003

IKONOS image mapping is being considered a possible replacement to the traditional mapping in many countries due to their ease of access to current data and their potential high resolution. Survey Department of His Majesty's Government completed traditional orthophoto mapping of all urban and semi-urban areas of the country. The 1:5000 monochrome orthophoto maps of Kathmandu Valley were completed in 2003. In 2002, as a test, production of a near natural colour Image Map at 1:5000 scale of a part of Kathmandu Valley based on IKONOS data was carried out. A conventional line map plotting of the same area at 1:5000 was also prepared. The objective of the pilot project was to assess the geometric accuracy and the information content of these maps. The details of the study and their results are underlined. The findings of the study helps to explain whether IKONOS image map can replace conventional orthophoto map at 1:5,000 for urban areas of Nepal like Kathmandu.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.44.2-44.2
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• 2009

Polycrystalline materials suchas yttria and alumina have been applied as a plasma resisting material for the plasma processing chamber. However, polycrystal line material may easily generate particles and the particles are sources of contamination during the plasma enhanced process. Amorphous material can be suitable to prevent particle generation due to absence of grain-boundaries. We manufactured nitrogen-containing $SiO_2-Al_2O_3-Y_2O_3$ based glasses with various contents of silicon and fixed nitrogen content. The thermal properties, mechanical properties and plasma etching rate were evaluated and compared for the different composition samples. The plasma etching behavior was estimated using XPS with depth profiling. From the result, the plasma etching rate highly depends on the silicon content and it may results from very low volatile temperature of SiF4 generated during plasma etching. The silicon concentration at the plasma etched surface was very low besides the concentration of yttrium and aluminum was relatively high than that of silicon due to high volatile temperature of fluorine compounds which consisted with aluminum and yttrium. Therefore, we conclude that the samples having low silicon content should be considered to obtain low plasma etching rate for the plasma resisting material.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.438-441
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• 2005

In a rapidly changing age of science and technology, important factor for the improvement of national competitive power is not only innovation development of scientific technique but also popularization of science, the understanding of general person about science. For popularization of science, scientific technical content serviced by using easy device and general person is interested in it's field. This paper suggests the E-mail Magazine content strategy for popularization of science. This suggestion is based on user's requirement investigation with on-line.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.1
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• pp.20-25
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• 1988

This experiment was conducted to find out the effects of the different cutting height on the chemical composition, energy production and relation of yields of Italian ryegrass, tall fescue and perennial ryegrass swards. It was carried out on the experimental field of Livestock Experiment Station, in Suweon, from Sept. 1986 to May 1987. The results obtained are summarized as follows: 1. Chemical composition and Van Soest fiber contents were slightly different among grasses. But were not same trend with cutting heights. At the late vegetative stage, crude protein and crude fiber content were much more in tall fescue, Ash in perennial ryegrass, E.E. and NFE in Italian ryegrass respectively. NDF, ADF, Hemicellulose, Lignin, Cellulose and Silica contents were much more in tall fescue than the others. 2. DM, DCP, TDN, StE, ME and NEL productions were appeared to high in line with Italian ryegrass, perennial ryegrass and tall fescue. In addition 6 cm cutting height was the most production in Italian ryegrass, 15 cm cutting height was the most production in perennial ryegrass and tall fescue. 3. The much more content of crude protein, the less nonstructural carbohydrate content. The less content of NDF, the much more nonstructural carbohydrate content. Green and dry matter yield before wintering were not influence the green and dry matter yield of the late vegetative stage, but green yield before wintering influenced total green yield.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.191-197
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• 2023

The purpose of the study was to provide an educational environment for designing and producing virtual reality practice contents that can be used in semiconductor production lines and clean rooms. Through this process, the user can acquire practical knowledge through experiences close to reality, such as experiencing the main semiconductor solar cell manufacturing facilities as well as procedural knowledge before and after entering the clean room.. In particular, it provides users with an immersion experience close to reality by creating an environment for experiential content necessary for semiconductor and solar cell manufacturing processes and clean room entrance procedure experiential content, which is expected to improve education immersion, realism, cost, efficiency, and education satisfaction. Depending on the characteristics of Dangerous, Impossible, Counter-productive etc, immersive content makes learners immersed in the learning content, induces proactive/active learning, and embodies the learning content, resulting in positive results in the field of improving educational effectiveness.