• Journal of Welding and Joining
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• v.32 no.3
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• pp.68-73
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• 2014

Among through silicon via (TSV) technologies, for replacing Cu filling method, the method of molten solder filling has been proposed to reduce filling cost and filling time. However, because Sn alloy which has a high coefficient of thermal expansion (CTE) than Cu, CTE mismatch between Si and molten solder induced higher thermal stress than Cu filling method. This thermal stress can deteriorate reliability of TSV by forming defects like void, crack and so on. Therefore, we fabricated SiC composite filling material which had a low CTE for reducing thermal stress in TSV. To add SiC nano particles to molten solder, ball-typed SiC clusters, which were formed with Sn powders and SiC nano particles by ball mill process, put into molten Sn and then, nano particle-dispersed SiC composite filling material was produced. In the case of 1 wt.% of SiC particle, the CTE showed a lowest value which was a $14.8ppm/^{\circ}C$ and this value was lower than CTE of Cu. Up to 1 wt.% of SiC particle, Young's modulus increased as wt.% of SiC particle increased. And also, we observed cross-sectioned TSV which was filled with 1 wt.% of SiC particle and we confirmed a possibility of SiC composite material as a TSV filling material.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.1-14
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• 2020

Leading the fourth industrial revolution era requires science and technology strategies that establish original research directions at the national level. To this end, it is necessary to look at the research and development activities for the fourth industrial revolution of technology-leading countries. In this study, the research programs of the U.S. Intelligence Advanced Research Projects Activity(IARPA), an organization focusing on cutting edge research on science and technology information such as artificial intelligence, are investigated by using network analysis. The findings show that, resolving around the information identification and forecasting, decision making and cybersecurity clusters, IARPA's research programs largely focus on finding hidden information and predicting specific events, supporting decision making by considering changes in and outside organizations or establishing cybersecurity. Also, this study finds that China and Japan, representative technology-leading Asian countries, refer to the research programs of IARPA to establish their science and technology policies. The results of this study suggest implications for Korea's science and technology policies in response to the fourth industrial revolution era.

• Analytical Science and Technology
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• v.15 no.6
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• pp.540-549
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• 2002

The arrangement of encapsulated Ar atoms in the molecular-dimensioned cavities of fully dehydrated zeolite A of unit-cell composition $Cs_3Na_8HSi_{12}Al_{12}O_{48}$ ($Cs_3$-A) has been studied crystallographically to probe the confinement effect of guest species in microporous environment. Atoms of Ar were encapsulated in the cavities of $Cs_3$-A by treatment with 410 atm of Ar at $400^{\circ}C$ for two days, followed by cooling at room temperature. The crystal structure of $Cs_3Na_8H$-A(4Ar) ($P_e$ = 410 atm, $a=12.245(2){\AA}$, $R_1=0.0543$, and $R_2=0.0552$) has been determined by single crystal X-ray diffraction technique in the cubic space group $Pm\bar{3}m$ at 21 (1) $^{\circ}C$ and 1 atm. Encapsulated Ar atoms are distributed in three crystallographic distinct positions: 1.5 Ar atoms per unit cell opposite 6-rings, 1.5 opposite four-rings in the large cavity, and finally 1.0 in the sodalite-unit. The possible structures of argon clusters, such as $Ar_2$, $Ar_3$, and $Ar_4$, are proposed.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.141-141
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• 2010

The effect of thermal anneal on the characteristics of structural properties and the enhancement of luminescence and photovoltaic (PV) characteristics of silicon-rich silicon-nitride films were investigated. By using an ultra high vacuum ion beam sputtering deposition, B-doped silicon-rich silicon-nitride (SRSN) thin films, with excess silicon content of 15 at. %, on P-doped (n-type) Si substrate was fabricated, sputtering a highly B doped Si wafer with a BN chip by N plasma. In order to examine the influence of thermal anneal, films were then annealed at different temperature up to $1100^{\circ}C$ under $N_2$ environment. Raman, X-ray diffraction, and X-ray photoemission spectroscopy did not show any reliable evidence of amorphous or crystalline Si clusters allowing us concluding that nearly no Si nano-cluster could be formed through the precipitation of excess Si from SRSN matrix during thermal anneal. Instead, results of Fourier transform infrared and X-ray photoemission spectroscopy clearly indicated that defective, amorphous Si-N matrix of films was changed to be well-ordered thanks to high temperature anneal. The measurement of spectral ellipsometry in UV-visible range was carried out and we found that the optical absorption edge of film was shifted to higher energy as the anneal temperature increased as the results of thermal anneal induced formation of $Si_3N_4$-like matrix. These are consistent with the observation that higher visible photoluminescence, which is likely due to the presence of Si-N bonds, from anneals at higher temperature. Based on these films, PV cells were fabricated by the formation of front/back metal electrodes. For all cells, typical I-V characteristic of p-n diode junction was observed. We also tried to measure PV properties using a solar-simulator and confirmed successful operation of PV devices. Carrier transport mechanism depending on anneal temperature and the implication of PV cells based on SRSN films were also discussed.

• Journal of Practical Engineering Education
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• v.11 no.2
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• pp.259-268
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• 2019

The purpose of the study was to examine the vocational educational system of Egypt, focusing on the effectiveness of the three consecutive cycle-based curriculum and integrated technical education clusters (ITECs) in order to suggest some implications for innovating the current vocational education system of Korea. The vocational education system of Egypt is similar to that of Korea, in terms of general education to go to university and vocational education to go to labor market. However, the Egyptian system is different from the system of Korea in light of the three consecutive cycle-based curriculum that links secondary vocational education, vocational education of college level, and advanced technical and vocational education. In addition, the Egyptian system has adopted the "cluster" approach which integrates technical secondary school, intermediate technical college, and advanced technical college around one physical area so as to promote vocational education in collaboration with regional industries and to guarantee education quality. In the last part, some potential implications were suggested for upgrading the quality of vocational education of Korea based upon the benchmark results of the Egyptian vocational education system and career development of students.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.735-741
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• 2009

In order to support the basic information for planning and performing the environment management such as Total Maximum Daily Loads (TMDLs), it is highly recommended to understand the spatial distribution of water quality and runoff data in the unit watersheds. Therefore, in the present study, we applied Self-Organizing Map (SOM) to detect the characteristics of spatial distribution of Biological Oxygen Demand (BOD) concentration and runoff data which have been measured in the Yeongsan, Seomjin, and Tamjin River basins. For the purpose, the input dataset for SOM was constructed with the mean, standard deviation, skewness, and kurtosis values of the respective data measured from the stations of 22-subbasins in the rivers. The results showed that the $4{\times}4$ array structure of SOM was selected by the trial and error method and the best performance was revealed when it classified the stations into three clusters according to the basic statistics. The cluster-1 and 2 were classified primarily by the skewness and kurtosis of runoff data and the cluster-3 including the basic statistics of YB_B, YB_C, and YB_D stations was clearly decomposed by the mean value of BOD concentration showing the worst condition of water quality among the three clusters. Consequently, the methodology based on the SOM proposed in the present study can be considered that it is highly applicable to detect the spatial distribution of BOD concentration and runoff data and it can be used effectively for the further utilization using different water quality items as a data analysis tool.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.2
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• pp.173-191
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• 2018

Taking note of growing tendency of academic interests and policy applications with regard to social economy, this study aims to suggest economic geographical agenda for social economy. It is presumed that the orientation of social economy toward pursuing social value will exhibit unique spatial characteristics. Elements containing spatial implications have been identified through a review of hierarchial concepts including social innovation, social economy organization and social enterprise. Three approached are suggested as tools of understanding the spatial context of social economy: spatial characteristics inspiring social entrepreneurship, place-based context of decision-making by social economy organizations, and spaces formulated by interactions between the demand for solving social problems and the supply of economic resources. The investigation of social innovation clusters is required to focus on the differentiated characteristics from normal industrial clusters. It is also suggested that the concept of embeddedness be applied in the search of the essence and elements of social economy's ties with local community.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.218-218
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• 2017

Adzuki bean (Vigna angularis) has been extensively investigated due to their biological activities. In this study, total polyphenol content (TPC), total phenolic acid content (TPA), and total flavonoid content (TFC) in 209 Korean adzuki bean landraces were determined by colorimetric methods. Antioxidant effects were evaluated with the DPPH, ABTS, ferric reducing antioxidant power (FRAP), reducing power (RP), and SOD assays. TPC, TPA, and TFC in the 209 Korean adzuki bean landraces ranged from 1.1 to 11.7 mg gallic acid equivalents/g, 0.37 to 5.03 mg caffeic acid equivalents/g, and 0.17 to 0.91 mg quercetin equivalents/g, respectively. Antioxidant activities as assessed by the DPPH, ABTS, FRAP, PR, and SOD assays showed wide variation, ranging from 12.2 to 86.3 (IC50), 0.85 to 5.25 mg ascorbic acid equivalents (ASC)/g, 0.41 to 5.44 mg ASC/g, 0.54 to 1.83 mg ASC/g, and 60.4 to 142.8 (IC50), respectively. Using the relative antioxidant capacity index (RACI), we found that the IT189394 sample had the highest antioxidant activity. In clustering analysis, 209 Korean adzuki bean landraces were classified into three clusters. Among them, cluster I contained 22 accessions with higher antioxidant activities, TPC, TFC, and TPA and smaller seed sizes than the other clusters. We anticipate that these results will provide useful information for the development of adzuki bean-based functional foods.

• Journal of Digital Convergence
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• v.18 no.7
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• pp.73-84
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• 2020

The whole world is making a variety of efforts to cope with the revolutionary changes in the economy and society that are emerging from intelligent information technology. Therefore, this study defined national public officials' intelligence information competency in the intelligent information society, and tried to derive competency clusters and sub-elements. To achieve this objective, this study explores literature research about bloom's digital taxonomy, information competency, and national ICT policies and national public officials' intelligence information competency was defined based on bloom's digital taxonomy perspective was modified and supplemented with this study and provisional constituent elements of competency were derived. In addition, 5 experts verified the content validity. As a result, 7 competency clusters and 22 sub-elements are finally derived. The findings of this study are expected to be useful as the basis for the national intelligence information human resource development.

• Journal of the Korean association of regional geographers
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• v.15 no.5
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• pp.537-553
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• 2009

This study aims to present promotion strategies for regional industries by exploring the ways to build industrial cluster focusing on regional strategic industries of Gyeongsanbuk-do(province) which are related to innovation city, by taking Gyeongbuk innovation city as an example. This study presented the methods for linking with innovation cities that focus on regional strategic industries, along with the analysis on the linkage between regional industries and public organizations relocated to local regions. As to the methods for the linkage, methods to build clusters based on the characteristics of each industry, such as electronic information device, new material parts, biological oriental medicine, cultural tourism, eco-friendly energy, etc, which are strategic and leading industries of Gyeongsanbuk-do(province), were presented. It was inferred that the industries which have achieved fast growth such as IT and BT industries, required mutually interconnected collaboration through geographical proximity among related subjects, while sectors with mature technologies, such as automative parts, machinery, steel industries, etc, were found to require more extensive infrastructures like the support of transportation and distribution for promoting current clusters.