• 소성∙가공
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• 제13권1호
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• pp.53-58
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• 2004

The microstructural changes of Al-Zn-Mg-Cu alloy containing Sc during hot extrusion and post heat treatment were investigated. Two kinds of Al-Sc alloys with different alloying elements (B1, B2) were hot extruded to make T-shape bars at extrusion temperature of $380^{\circ}C$, then the bars were solution treated at $480^{\circ}C$ for 2hrs followed by artificial aging at $120^{\circ}C$ for 24hrs. The interior microstructure of as extruded bar consisted of elongated grains, however, fine equiaxed grains were also observed around surface. The microstructural gradient suggested that different restoration process could proceed during the hot extrusion. For B1 and B2, different grain growth behaviors were found around the surface during the post heat treatment. Rapid grain growth behavior was observed for B1 around the surface, however, it was not observed for B2. Orientation pinning, which was related with the evolution of preferred orientation, and precipitation were thought to be responsible for the rapid grain growth.

• 한국재료학회지
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• 제23권11호
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• pp.620-624
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• 2013

Nanocrystalline materials have recently received significant attention in the area of advanced materials engineering due to their improved physical and mechanical properties. A solid-solution nanocrystalline powder, (Ti,Mo)C, was prepared via high-energy milling of Ti-Mo alloys with graphite. Using XRD data, the synthesis process was investigated in terms of the phase evolution. Rapid sintering of nanostuctured (Ti,Mo)C hard materials was performed using a pulsed current activated sintering process (PCAS). This process allows quick densification to near theoretical density and inhibits grain growth. A dense, nanostructured (Ti,Mo)C hard material with a relative density of up to 96 % was produced by simultaneous application of 80 MPa and a pulsed current for 2 min. The average grain size of the (Ti,Mo)C was lower than 150 nm. The hardness and fracture toughness of the dense (Ti,Mo)C produced by PCAS were also evaluated. The fracture toughness of the (Ti,Mo)C was higher than that of TiC.

• 국제초고층학회논문집
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• 제7권4호
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• pp.265-285
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• 2018

This paper presents a state-of-the-art review on the design, research and education aspects of fire safety engineering (FSE) with a particular concern on high-rise buildings. FSE finds its root after Great Fire of Rome in 64 AD, followed by Great London Fire in 1666. The development of modern FSE is continuously driven by industry revolution, insurance community and government regulations. Now FSE has become a unique engineering discipline and is moving towards performance-based design since 1990s. The performance-based fire safety design (PBFSD) involves identification of fire safety goals, design objectives, establishment of performance criteria, and selection of proper solutions for fire safety. The determination of fire scenarios and design fires have now become major contents for PBFSD. To experience a rapid and positive evolution in design and research consistent with other engineering disciplines, it is important for fire safety engineering as a profession to set up a special educational system to deliver the next-generation fire safety engineers. High-rise buildings have their unique fire safety issues such as rapid fire and smoke spread, extended evacuation time, longer fire duration, mixed occupancies, etc., bringing more difficulties in ensuring life safety and protection of property and environment. A list of recommendations is proposed to improve the fire safety of high-rise buildings. In addition, some source information for specific knowledge and information on FSE is provided in Appendix.

• 한국산업융합학회 논문집
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• 제27권1호
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• pp.17-24
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• 2024

Recently, retail technology has been developed by the rapid evolution of e-commerce and a representative example is ESL technology. In this study, we investigate ESL technology, market status and forecasts, and analyze the competitive structure between relational companies. Market analysis refers to data from market reports of Marketsandmarkets and Research, and internet media. In ESL, the display field is predicted to account for 43% of the total market in 2026, and is converting from LCD to electronic paper. The segmented type is becoming more advanced into the full-graphic type, and CAGR of 18.7% for 3-7 inches and 20.6% for 7-10 inches is predicted. The demand for ESL is greatest in North America and Europe, but CAGR is the highest in the Asia-Pacific region at 19.1%. Since ESL technology has a lot of overlap with semiconductor and display technology, the Asia-Pacific region is relatively advantageous, and this has led to rapid growth of domestic companies. However, it is expected that competition from European companies that are actually owned by Chinese companies will increase in the future, so continuous technological development and new market development are necessary.

• Journal of Veterinary Science
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• 제21권5호
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• pp.79.1-79.12
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• 2020

Background: Recently, the pork industry of Thailand faced an epidemic of highly virulent strains of porcine reproductive and respiratory syndrome virus (PRRSV), which spread throughout Southeast Asia, including the Lao People's Democratic Republic and Cambodia. Hence, the rapid and on-site screening of infected pigs on a farm is essential. Objectives: To develop the new aptamer as a biosensor for detection PRRSV which are rapid and on-site screening of infected pig. Methods: New aptamers against PRSSV were identified using the combined techniques of capillary electrophoresis, colorimetric assay by gold nanoparticles, and quartz crystal microbalance (QCM). Results: Thirty-six candidate aptamers of the PRRSV were identified from the systematic evolution of ligands by exponential enrichment (SELEX) by capillary electrophoresis. Only 8 out of 36 aptamers could bind to the PRSSV, as shown in a colorimetric assay. Of the 8 aptamers tested, only the 1F aptamer could bind specifically to the PRSSV when presented with the classical swine fever virus and a pseudo rabies virus. The QCM was used to confirm the specificity and sensitivity of the 1F aptamer with a detection limit of 1.87 × 10¹⁰ particles. Conclusions: SELEX screening of the aptamer equipped with capillary electrophoresis potentially revealed promising candidates for detecting the PRRSV. The 1F aptamer exhibited the highest specificity and selectivity against the PRRSV. These findings suggest that 1F is a promising aptamer for further developing a novel PRRSV rapid detection kit.

• Fisheries and Aquatic Sciences
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• 제9권2호
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• pp.70-74
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• 2006

DNA sequence-based typing is considered a robust tool for the discrimination of dinoflagellate species because of the availability of extensive rDNA sequences. Here, we present a rapid, cost-effective DNA-sequencing technique for various PCR products. This sequencing strategy relies on 'nested' or 'tailed' primer labeled with near-infrared dye, and uses a minimal volume of unpurified PCR product (ca. $5{\mu}L$) as the DNA template for sequencing reactions. Reliable and accurate base identification was obtained for several hundred PCR fragments of rRNA genes. This quick, inexpensive technique is widely applicable to sequence-based typing in clinical applications, as well as to large-scale DNA sequencing of the same genomic regions from related species for studies of molecular evolution.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.39-39
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• 2003

Antioxidant enzyme genes play a key role in cell defense against the lethal effects of oxidative stresses in animals and have an essential function which has allowed the evolution of aerobic respiration starting from an ancient form of oxygen-insensitive life. Piscine antioxidant enzymes are also involved in the rapid response to various toxic chemicals as well as many biological stresses, indicating that they could be used as biomarkers for health and aquatic environment. With the purpose for developing fine molecular probing tool to assess the stresses in marine fish, we identified three major antioxidant enzyme genes (superoxide dismutase, catalase and glutathione-S-transferase) from Korean rock bream using expressed sequence tag analysis and/or high density filter screening. Here we report the molecular information on these gene transcripts including complete sequence data and expression profiles.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2573-2580
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• 2011

SMRT(Seoul Metropolitan Rapid Transit Corporation) changed PC-oriented office system to Smart-Phone oriented mobile office system(STnF: SMRT Talk & Flash), and provided smart phone to all staffs. STnF make it possible not only voice communication between staff, but also to input and inquiry all kind of information related to work(ex: Facility maintenance, Rolling Stock management, office management, Finance, human resource etc.) based on smart phone. STnF conquers the limitation of time and space. All staffs can commute to the site directly to reduce moving time and to share information between staffs, so SMRT improve speed and reliability of work by making a quick decision and action on the spot. After introduction of STnF, within 1 year, the equipment failure ratio fell to 47%. Mobile office system reduced and level-off the step of approval. so enhanced civil customer service. Quantification and scientific movement of work make it fast evolution and development. These business improvement make it possible to put more outstanding manpower on new business and R&D project, and this contributes to company's management effectiveness.

• Asian Journal of Innovation and Policy
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• 제4권1호
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• pp.103-127
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• 2015

This paper investigates the two academic revolutions of the Korean higher education system. Since economic catch-up began in the 1960s, Korea has strongly encouraged the activities of its higher education system to serve industrial development as it has progressed through various developmental stages. At the 'strong regulation' stage, universities focused on the provision of technicians. As the need for higher education grew, the 'massive expansion' stage emerged. Finally, most recently, university research and its direct contribution to the economy have been invigorated by strong governmental support. Possibly, this is due to the fact that the Korean government has strongly controlled not only industry but also academia. As long as other East Asian universities have similar conditions to those of the development of Korean universities, we can generalise this model not only to universities in other East Asian countries, but also to universities in other rapid catch-up countries.

• 한국CDE학회논문집
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• 제12권1호
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• pp.1-7
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• 2007

In this paper, we present a machining time estimation algorithm for 5-axis high-speed machining. Estimation of machining time plays an important role in process planning and production scheduling of a shop. In contrast to the rapid evolution of machine tools and controllers, machining time calculation is still based on simple algorithms of tool path length divided by input feedrates of NC data, with some additional factors from experience. We propose an algorithm based on 5-axis machine behavior in order to predict machining time more exactly. For this purpose, we first investigated the operational characteristics of 5-axis machines. Then, we defined some dominant factors, including feed angle that is an independent variable for machining speed. With these factors, we have developed a machining time calculation algorithm that has a good accuracy not only in 3-axis machining, but also in 5-axis high-speed machining.