• Nuclear Engineering and Technology
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• v.42 no.6
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• pp.662-669
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• 2010

To develop the manufacturing methods for the blanket first wall (FW) of the International Thermonuclear Experimental Reactor (ITER) and to verify the integrity of the joint, Be/Cu mockups were fabricated and tested at the KoHLT-1 (Korea Heat Load Test facility), a graphite heater facility located at the Korea Atomic Energy Research Institute (KAERI). Since Be and Cu joining is the focus of the present study, the fabricated mockups had a CuCrZr heat sink joined with three Be tiles as an armor material, unlike the original ITER blanket FW, which has a stainless steel structure and coolant tubes. Hot isostatic pressing (HIP) was carried out at $580^{\circ}C$ and 100 MPa for 2 hours as the method for Be/Cu joining. Three interlayers, namely, $1{\mu}mCr/10{\mu}mCu$, $1{\mu}mTi/0.5{\mu}mCr/10{\mu}mCu$, and $5{\mu}mTi/10{\mu}mCu$ were applied as a coating to the Be tiles by a physical vapor deposition (PVD) method. A shear test was performed with the specimens, which were fabricated by the same methods as those used to fabricate the mockups. The average values were 125 MPa to 180 MPa, and the samples with the $1{\mu}mCr/10{\mu}mCu$ interlayer showed the lowest value. No defect or delamination was found in the joints of the mockups by the developed ultrasonic test using a flat-type probe with a 10 MHz frequency and a 0.25 inch diameter. High heat flux (HHF) tests were performed at $1.0\;MW/m^2$ heat flux for each mockup using the given conditions, and the results were analyzed by ANSYS-CFX code. For the test criteria, an expected fatigue lifetime about 1,000 cycles was obtained by analysis with ANSYS-mechanical code. Mockups using the interlayers of $1{\mu}mTi/0.5{\mu}mCr/10{\mu}mCu$ and $5{\mu}mTi/10{\mu}mCu$ survived up to 1,100 cycles over the required number of cycles. However, one of the Be tiles in the other two mockups using the $1{\mu}mCr/10{\mu}mCu$ interlayer was detached during the screening test, and others were detached by discharge after 862 cycles. The integrity of the joints using the proposed interlayers was proven by the HHF test, but the other interlayer requires more study before it can be used for the joining of Be to Cu. Moreover, it was confirmed that the measured temperatures agreed well with the analysis temperatures, which were used to estimate the lifetime and that the developed facility showed its capability of the long time operation.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.76-81
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• 2012

Silk protein has been explored to be used for biomedical applications for several decades. However, it has not been used in this field cause to their irreversible crystallization after dissolving in water. The existing methods of silk protein hydrolysis using silkworm cocoon were used with harmful solvents and through a very complicated process. Therefore, we have developed novel methods for the production of water-soluble hydrolysate using silkworm gland. We manufactured two types of silkworm gland-derived hydrolysate (water-soluble SGH, SSGH; total SGH, TSGH) and compared the characteristics with commercial cocoon-derived sericin hydrolysate (CSH). The molecular weight of SGH ranged from 7 to 50 kDa (SSGH) and 5 to 15 kDa (TSGH) within glycine, alanine, and aspartic acid as a main amino acid composition. In contrast, CSH ranged from 15 to 50 kDa within serine and aspartic acid. The results of FTIR implied that SGH was more soluble form than CSH, as shown by the decrease in the ${\beta}$-sheet structure at $1630cm^{-1}$ on amide I peak. In comparison with 10% fetal bovine serum, 0.1% (1 mg/ml) SSGH had equivalent effect on the proliferation of human dermal fibroblasts and mesenchymal stem cells. All results of the SSGH made by novel manufacturing process indicate the SSGH is more preferable as a culture medium supplement than cocoon-derived sericin.

• Land and Housing Review
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• v.12 no.3
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• pp.67-78
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• 2021

After World War II, modular housing was developed as a means of quickly and efficiently meeting the housing supply demand. For the past 30 plus years, efforts have been made to improve modular housing in South Korea and to increase their competitiveness in the housing market. This study investigated modular houses based on a steel framed rahem structure which provides a flexible floor plan where walls are easily reconfigured to create rooms of various sizes and functions. Similar to the factory production methods used in the automotive industry, the modular housing industry can also benefit by standardizing such aspects as building components, manufacturing and construction methods, materials, process management, and floor plans. This study examined the feasibility of using a 3m × 3m module for developing various floor plans which are easy to produce and transport. Each 3m × 3m module can be configured to meet different living needs resulting in a complete home when multiple modules are connected. The module configurations can be varied to meet ground transportation and crane limitations. This study found that a 3m × 3m steel framed modular unit is a promising step towards providing residents with plans that meet their living preferences while improving and increasing the supply of modular houses.

• The Journal of Society for e-Business Studies
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• v.24 no.3
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• pp.19-33
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• 2019

Recently, manufacturers have been struggling to efficiently use production equipment as their production methods become more sophisticated and complex. Typical factors hindering the efficiency of the manufacturing process include setup cost due to job change. Especially, in the process of using expensive production equipment such as semiconductor / LCD process, efficient use of equipment is very important. Balancing the tradeoff between meeting the deadline and minimizing setup cost incurred by changes of work type is crucial planning task. In this study, we developed a scheduling model to achieve the goal of minimizing the duedate and setup costs by using reinforcement learning in parallel machines with duedate and work preparation costs. The proposed model is a Deep Q-Network (DQN) scheduling model and is a reinforcement learning-based model. To validate the effectiveness of our proposed model, we compared it against the heuristic model and DNN(deep neural network) based model. It was confirmed that our proposed DQN method causes less due date violation and setup costs than the benchmark methods.

• Journal of Korean Society for Quality Management
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• v.46 no.4
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• pp.843-862
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• 2018

Purpose: The purpose of this study was to develop quality innovation techniques specialized for the small and medium-sized businesses. which account for the majority of Korean companies, were having a hard time utilizing the widely recognized quality innovation techniques due to resource constraints. Methods: First, we do review the existing Single PPM and 6 Sigma. And investigate the utilization of these methods including Toyota Production System. Second, we devised a four-step problem-solving methodology based on recent trends in quality innovation such as Simple, Speedy, and Smart. Third, we do survey on frequently used tools for quality innovation. Many opinion leaders including quality consultants and professors answered and gave us valuable comments about our selected quality tools. Finally, we do specify and map tools to each step of PASS. Results: In 2017, 167 companies participated in the quality innovation support business for small businesses according to the Korea Chamber of Commerce & Industry. We conducted performance checks on 167 companies that had completed the "PASS" projects. For the purpose of evaluating improvement performance, the survey was carried out using a structured questionnaire during the field visit of these companies mentioned above. For the reference, 165 out of 167 companies (98.8 % response rate) responded to the questionnaire and conducted performance analysis based on it. According to the survey, 97.6 percent of the respondents were very satisfied with their overall satisfaction with the quality innovation support projects for small and medium sized enterprises in 2017. Also, 93.3 % of the respondents were satisfied with the results of level of the target achievement. As a result, 160 companies (97.0 % of the participating companies) hope to partic ipate in the quality improvement project using "PASS" once again. Conclusion: In this paper, we introduce the new quality innovation methodology, which is named as 'PASS', It could support the long-range business plan of the small and medium-sized businesses to achieve total customer satisfaction resulting in increased market share and improved profit margin. The most small companies can use this "PASS" technique more easily, quickly and most efficiently than their existing known quality innovation techniques such as Six Sigma and Single PPM, etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.74-80
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• 2021

This study investigated the process quality level of a K5 gas mask, which recently acquired its operational capability, through statistical process analysis for the mass production stages and their lots. The tensile adhesion strength was the only operating requirement in the manufacturing process of the K5 gas mask. For this purpose, the results of tensile adhesion strength between the lens and facial rubber during the initial and second mass production stages were analyzed using conventional statistical and statistical process analysis methods. The conventional statistical results indicated that the second mass production stage was better than the initial mass production stage. In cases of a control chart and process capability of tensile adhesion strength, the process quality level was also improved by following the mass production stages. The improvement was caused by process stabilization and work skill elevation. These results and methods are expected to be conducted and utilized in the third mass production stage. Moreover, quality improvement of K5 gas mask mass production can be achieved using the Lean 6 sigma procedure, MDAIC (Define, Measure, Analyze, Improve, Control).

• Food Science and Industry
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• v.53 no.1
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• pp.69-83
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• 2020

For the development of the chitosan industry in Korea, the catch of red snow crabs caught on the east coast is rapidly decreasing. Therefore, it is urgent to develop raw materials that can replace the red snow crab as the top priority to solve the supply and demand problems, as well as wastewater treatment costs account for a large proportion of the cost of chitosan. In order to solve the problems, continuous research on biological extraction methods such as enzymatic extraction and microbial fermentation will increase production efficiency and lower unit cost as well as chemical extraction methods. Further efficient manufacturing method can be established. Establishing of novel techniques is indispensable for production of high-purity chitosan and the ability to regulate and separate the molecular weight, as well as joint research with industry, academia and research institute for the research and development of high-functional chitosan derivatives.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.434-439
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• 2020

Selective laser melting (SLM) manufactures an alloy using laser as a heat source, and has recently been introduced in the dental industry. However, there is a lack of analytical research on metal-ceramic restorations achieved by SLM. This study evaluates and compares the metal-ceramic bond strength of Co-Cr alloys produced by selective laser melting and casting methods. Co-Cr samples required for this study were produced through the sintering process of ceramics, by applying the SLM and CAST methods. The metal-ceramic bond strength was measured by applying the shear bond strength test. In order to determine the area fraction of adherent ceramic, Si content of the specimen was measured using scanning electron microscopy SEM/ EDS. Results of the metal-ceramic bond strength and AFAC were analyzed by t-test (α = 0.05). No significant difference was observed comparing the bond strength of SLM and CAST Co-Cr alloys (P> 0.05). However, the SLM group had much better ceramic adherence than the CAST group (P < 0.001). Moreover, oxidation characteristics were similar for both SLM and CAST Co-Cr alloys, but metal structures were different. These results imply that although the bond of ceramic and Co-Cr alloy is not related to the manufacturing method, SLM alloys impart better ceramic adherence. This indicates that alloys made with SLM can be used to fabricate upper implant prostheses in the future. In particular, it is expected to overcome the shortcomings of the CAST method, and save time and cost.

• Conservation Science in Museum
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• v.26
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• pp.143-160
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• 2021

The Seoul Baekje Museum has been conducting excavations at the Ancient Tomb Complex in Seokchon-dong, Seoul (Historic Site No. 243), known to be tombs of the royal family and the ruling class during the Hanseong period of the Baekje Kingdom. In this study, gold earrings that were revealed during the excavation underwent scientific analysis and conservation treatment. Stereo microscopy, SEM, X-ray imaging, CT, and XRF were applied in the analysis, and the characteristics, internal structure, and composition of the earrings as well as their production method were investigated. The results confirmed that the main hoops of the gilt-bronze earrings were made of copper cores gilt using mercury amalgamation. The findings also revealed that the hexahedron in the middle pendant was made by connecting small rings using molten gold powder, and the pendant sphere at the end was formed by soldering two hemispheres. As for the two thin-hoop earrings, they showed similar surface compositions but were made using different methods, with one made from a copper core wrapped with a gold plate and the other made by bending a gold rod. The gold content varied depending on the item and the place of measurement, but overall the earrings showed a relatively high gold content of approximately 19 to 21K. The purity of the golden earrings and the sophisticated manufacturing techniques applied indicate the high status of the buried person and of the tomb complex in Seokchong-dong.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.144-150
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• 2002

Indian mallow is characterized by the rapid growth and high harvest of the fibrous materials. This study was carried out to investigate the sheet properties of Hanji using Indian mallow, made by different pulping methods, such as alkali and sulfomethylated pulpings and different stock compositions, various mixing ratios of bast fiber, woody core and whole stalk fibers. The results from this study were summarized as follows. The length and width of the bast fibers were 1.40-430 mm(av. 235 mm), and 9.2-26.4 ㎛(av.18.3 ㎛), respectively. The cell wall thickness was 4.0-115 ㎛(av. 7.7 ㎛). Runkel ratio, flexibility coefficient and fiber length/fiber width ratio were 1.38, 0.42 and 128 respectively. Bast fiber and whole stalk were cooked by alkali and sulfomethylated methods. Sulfomethylated pulping resulted in superior pulp in terms of yield and quality as compared with those of alkali pulping. The pulp yields of bast fiber was higher than those of whole stalk