• Journal of the Korean Society for Heat Treatment
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• v.37 no.3
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• pp.114-120
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• 2024

AA 2026, which is used as an aviation material, is an improved version of 2024 and has higher physical properties, and is a material that has the potential to be applied to supersonic aircraft to be developed in the future. However, when an aircraft exceeds supersonic speeds, the surface heats up and the material must be resistant to this. Therefore, this study confirmed the high-temperature properties of AA 2026, an aviation structural material. AA 2026, solution treated at 500℃ for 4hr, was naturally aged at room temperature for more than 168 hr. Changes in microstructure and physical properties were confirmed over several hours of exposure to 100℃, 200℃, and 300℃, respectively. As a result of microstructure analysis, there was no significant change at 100℃, and from 200℃, GPB, a strengthening mechanism, grew and formed an S Phase. It was confirmed that the S Phase grew as the exposure time increased. Through a tensile test, it was confirmed that physical properties deteriorated as the precipitates grew. However, it was confirmed that the properties were stably maintained at 100℃, which is the temperature when the speed of a supersonic aircraft is less than Mach 2.

• Design & Manufacturing
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• v.15 no.2
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• pp.1-10
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• 2021

In this study, the current state of the plastics industry has been examined. The direction of development and innovation is reviewed and commented. The technical statuses of various sectors such as thermoplastic resin, composite material, mold engineering, and simulation have been scrutinized. In addition, the industrial status of each sector has been reviewed. Then, the challenges that the plastics manufacturing industry has to deal with have been discussed. Especially, the situation in Republic of Korea has been elaborated in detail. Based on the discussion, an open innovation strategy has been suggested. It has been argued in this work that the open innovation strategy will enables efficient funding and development by avoiding resource consuming rent seeking.

• Progress in Superconductivity and Cryogenics
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• v.24 no.1
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• pp.8-12
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• 2022

Recently, research on applying composite materials to various industrial fields is being actively conducted. In particular, composite materials fabricated by Fused Deposition Modeling 3D printers have more advantages than existing materials as they have fewer restrictions on manufacturing shape, reduce the time required, weight. With these advantages, it is possible to consider utilizing composite materials in cryogenic environments such as the application of liquid oxygen and liquid hydrogen, which are mainly used in an aerospace and mobility. However, FDM composite materials are not verified in cryogenic environments less than 150K. This study evaluates the characteristics of composite materials such as tensile strength and strain using a UTM (Universal Testing Machine). The specimen is immersed in liquid nitrogen (77 K) to cool down during the test. The specimen is fabricated using 3D print, and can be manufactured by stacking reinforced fibers such as carbon fiber, fiber glass, and aramid fiber (Kevlar) with base material (Onyx). For the experimental method and specimen shape, international standards ASTM D638 and ASTM D3039 for tensile testing of composite materials were referenced.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.4
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• pp.177-185
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• 2021

Over the past 40 years, Korea's defense industry has been deepening into a low-efficiency industrial structure as the government directly controls prices, quantities, and costs. By implementing the Defense Industry Building Act in 2021, the government is creating a healthy ecosystem for the defense industry and strengthening its global competitiveness. In this study, based on KPC's Productivity Management System (PMS), a diagnostic model of defense companies implemented since 2013, the on-site diagnosis was performed from 4 to 28 days depending on the size of the company data was collected based on the results. The causal relationship was analyzed through structural equation model path analysis for the effect of innovation capability on productivity performance. As a result, it suggests that defense materials suppliers should focus on which core processes to innovate and strengthen and improve their innovation capabilities.

• International Commerce and Information Review
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• v.17 no.1
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• pp.193-214
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• 2015

This study was conducted to explore the impact of the strategic supply chain orientation on the supply chain performance of raw materials export-import firms. In addition, this study analyzed the mediated effect of innovation and information sharing between the strategic supply chain orientation and supply chain performance of the firms. In the research model of this study considered the strategic supply chain orientation, innovation, information sharing and supply chain performance as the characteristics of the raw materials export-import firms by dividing the learning performance and market performance. The sample firms be analyzed were 445 firms. The 7 hypothesis including moderated effect were analyzed by using LISREL as structural equation modeling. According to the path analysis, the strategic supply chain orientation had a positive impact on the innovation activity. However, it did not have a positive influence on the information sharing. In the analysis of the mediated effect, the innovation activity of supply chain showed a full mediated effect between the strategic supply chain orientation and the information sharing. And the information sharing showed a partial mediated effect between the strategic supply chain orientation of these firms and the supply chain performance.

• The Plant Pathology Journal
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• v.37 no.2
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• pp.200-203
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• 2021

Rice blast caused by the filamentous fungus Magnaporthe oryzae, is arguably the most devastating rice disease worldwide. Development of a high-throughput and reliable field blast resistance evaluation system is essential for resistant germplasm screening, resistance genes identification and resistant varieties breeding. However, the occurrence of rice blast in paddy field is easily affected by various factors, particularly lack of sufficient inoculum, which always leads to the non-uniform occurrence and reduced disease severity. Here, we described a procedure for adequately inducing the occurrence of rice seedling blast in paddy field, which involves pretreatment of diseased straw, initiation of seedling blast for the first batch of spreader population, inducing the occurrence of the second batch of spreader population and test materials. This procedure enables uniform and consistent infection, which facilitates efficient and accurate assessment of seedling blast resistance for diverse rice materials.

• Journal of the Korean Geographical Society
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• v.40 no.1 s.106
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• pp.78-95
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• 2005

The purpose of this paper is to analyze industrial and innovation networks of long-live area of Honam Region and to suggest a policy direction for regional development of rural areas where have been neglected in the knowledge-based information society. Four counties (Sunchang, Damyang, Gokseong, and Gurye) in the Southwestern region of Korea are regarded as long-live belt of Korea. Production and innovation networks :Ire analyzed based on intensive surveys of firms in the belt. Major findings from the surveys are as follows. First, there are considerably strong local networks of production firms in terms of supply of input materials and labor. There are strong backward industrial linkages of the production firms with agricultural activities and considerable forward linkages with tourism industry. In addition, Internet is becoming a useful tool for sales of the new products. Second, the analysis of the innovation networks in the long-live area suggests the development of 'virtual innovation cluster' in the era of knowledge-based information society. The results imply that this innovation networks can be developed as a virtual innovation cluster in the rural areas, which can be the basis for the development of rural innovation systems.

• Electronic Materials Letters
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• v.14 no.6
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• pp.718-724
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• 2018

With the development of photovoltaic industry, the cost of photovoltaic power generation has become the significant issue. And the metallization process has decided the cost of original materials and photovoltaic efficiency of the solar cells. Nowadays, double printing process has been introduced instead of one-step printing process for front contact of polycrystalline silicon solar cells, which can effectively improve the photovoltaic conversion efficiency of silicon solar cells. Here, the relative cheap Cu paste has replaced the expensive Ag paste to form Ag/Cu composite front contact of silicon solar cells. The photovoltaic performance and the cost of photovoltaic power generation have been investigated. With the optimization on structure and height of Cu finger layer for Ag/Cu composite double-printed front contact, the silicon solar cells have exhibited a photovoltaic conversion efficiency of 18.41%, which has reduced 3.42 cent per Watt for the cost of photovoltaic power generation.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.95-109
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• 2017

There are several contributions to the gas load of a system of which often the most important is outgassing. Adsorption occurs via two main processes, physisorption and chemisorption, and can be described using five (or six) classifying isotherms. Outgassing is the result of desorption of previously adsorbed molecules, bulk diffusion, permeation and vapourisation. Looking at the desorption rate, pumping speed and readsorption on surfaces, the net outgassing of the system can be calculated. There is significant variation in measured outgassing rates between different materials but also between published rates for the same materials, in part due to the number of different methods used to measure outgassing. This article aims to review the outgassing process, outgassing rates, measurement methods and techniques that can be used to reduce the outgassing of a system.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.602-603
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• 2006

Micro-porous nickel (Ni) with an open cell structure was fabricated by powder metallurgy. The pore size of the micro-porous Ni approximated $30{\mu}m$ and $150{\mu}m$. For comparison, porous Ni with a macro-porous structure were also prepared by both powder metallurgy (pore size $800{\mu}m$) and the traditional chemical vapour deposition method (pore size $1300{\mu}m$). The mechanical properties of the micro-and macro-porous Ni samples were evaluated using compressive tests. Results indicate that the micro-porous Ni samples exhibited significantly enhanced mechanical properties, compared to those of the macro-porous Ni samples.