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과학계량학적 정보분석을 통한 LED 및 광분야 유망기술 탐색에 관한 연구
장시영(Chang, Si-Young),이병철(Lee, Byoung-Chul),김윤배(Kim, Yun-Bae) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.3
본 연구는 과학계량학(scientometrics)을 활용하여 LED 및 광분야의 유망기술을 탐색하였다. 우선 Web of Science의 SCIE 논문 및 미국특허청(USTPO) 특허를 수집하여 키워드를 추출하였다. 추출된 키워드를 클렌징 과정을 통해 표준화하고, 동시단어 분석을 사용하여 LED 및 광분야의 논문과 특허 서지사항에 나타나는 정보간의 연합강도 (association strength)를 측정함으로써 기술의 패턴 및 경향을 밝혀내었다. 그리고 LED 및 광분야의 역동적인 변화를 추적하기 위하여 전략적 다이어그램을 도출하였다. 이를 통해 LED 및 광분야의 미래 유망연구영역 및 기술도출의 객관적인 방법으로서 과학계량학의 가능성을 보여준다. The aim of this research is to map the intellectual structure of the field of LED and optics during the period of 2000-2009. We utilize the scientometric tool of co-word analysis to reveal patterns and trends in the LED and optics field by measuring the association strengths of keywords (or IPCs). Data were collected from Science Citation Index Expanded (SCIE) and United Stated Patent and Trademark Office (USTPO) for the period of 2000-2009. Keywords were extracted from abstracts and further standardized using thesaurus. In order to trace the dynamic changes of the LED and optics field, the whole 10-year period was separated into two consecutive periods: 2000-2004 and 2005-2009. The results show that the LED and optics field has some established research themes and it also changes to embrace new themes.
듀오캐스트 Al-Mg-Si/Al 하이브리드 합금의 미세조직과 기계적 변형 특성
한지민 ( Ji Min Han ),김종호 ( Chong Ho Kim ),박준표 ( Jun Pyo Park ),장시영 ( Si Young Chang ) 한국주조공학회 2012 한국주조공학회지 Vol.32 No.6
Al-Mg-Si/Al hybrid alloy was prepared by Duo-casting and the mechanical behavior was evaluated based on their microstructure and mechanical properties. The hybrid aluminum alloy included the Al-Mg-Si alloy with fine eutectic structure, pure Al with the grains in pure Al occurred from the macro-interface existing between Al-Mg-Si/ alloy and pure Al. The growth of columnar grains in pure Al occurred from the macro-interface. The tensile strength, 0.2% proof stress and bending strength of the hybrid aluminum alloy were almost similar to those of pure Al, and the elongation was much higher than the Al-Mg-Si alloy. The fracture of the hybrid alloy took place in pure Al side, indicating that the macro-interface was bonded and the mechanical behavior strongly depends on the limited deformation in pure Al side.
EMS Al-Mg-Si/Al 하이브리드 합금의 계면에 미치는 열처리의 영향
이호훈(Ho Hun Lee),박성진(Sung-Jin Park),김종호(Jong-Ho Kim),박준표(Jun-Pyo Park),장시영(Si Young Chang) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.10
Al-Mg-Si/Al hybrid alloy was fabricated by Duo-casting, which is subject to the electromagnetic stirring(EMS), and the effect of heat treatment on interfacial characteristics was studied. After fabricating the hybrid alloy, some specimens were annealed at 100, 300 and 500℃ for 1h. And the other specimens were T6 treated (solution treatment at 500℃ for 1h, and aging at 160℃ for 5h). To investigate the effect of heat treatment, microstructure was observed by optical microscopy and scanning electron microscopy, and microhardness was measured. As annealing temperature increased, grain size of Al-Mg-Si alloy increased, and T6 heat treated Al-Mg-Si alloy showed a slight change in grain size. Near the macrointerface of hybrid alloy, microhardness increased gradually from pure Al side to Al-Mg-Si alloy side.
전자기 듀오캐스팅으로 제조한 Al-Mn/Al-Si 하이브리드 알루미늄합금의 미세조직과 인장 특성
박성진,김종호,박준표,장시영,Park, Sung-Jin,Li, Tingju,Kim, Chong-Ho,Park, Jun-Pyo,Chang, Si-Young 한국재료학회 2012 한국재료학회지 Vol.22 No.2
The microstructure and tensile properties of Al-Mn/Al-Si hybrid aluminum alloys prepared by electromagnetic duocasting were investigated. Only the Al-Mn alloy showed the typical cast microstructure of columnar and equiaxed crystals. The primary dendrites and eutectic structure were clearly observed in the Al-Si alloy. There existed a macro-interface of Al-Mn/Al-Si alloys in the hybrid aluminum alloys. The macro-interface was well bonded, and the growth of primary dendrites in Al-Si alloy occurred from the macro-interface. The Al-Mn/Al-Si hybrid aluminum alloys with a well-bonded macro-interface showed excellent tensile strength and 0.2% proof stress, both of which are comparable to those values for binary Al-Mn alloy, indicating that the strength is preferentially dominated by the deformation of the Al-Mn alloy side. However, the degree of elongation was between that of binary Al-Mn and Al-Si alloys. The Al-Mn/Al-Si hybrid aluminum alloys were fractured on the Al-Mn alloy side. This was considered to have resulted from the limited deformation in the Al-Mn alloy side, which led to relatively low elongation compared to the binary Al-Mn alloy.
플라즈마 전해 산화처리한 시효경화 Mg-Al 합금 피막의 기계적 및 전기화학적 특성
장시영,김예림,김양도,Chang, Si-Young,Kim, Ye-Lim,Kim, Yang-Do 한국재료학회 2007 한국재료학회지 Vol.17 No.12
Plasma electrolytic oxidation (PEO) treatment was performed on cast Mg-6 wt%Al alloy solution-treated at 693K for 16h and aged at 498K. The surface roughness, thickness, micro-hardness, wear and corrosion properties of coatings on solution-treated and aged Mg-6 wt%Al alloy were investigated. The coatings on aged Mg-6 wt%Al alloy had thinner layer and lower micro-hardness and wear resistance than the solution-treated Mg-6 wt%Al alloy. As the aging time increased, the thickness of coatings decreased while the surface roughness was almost no changed. In addition, the micro-hardness and wear property of coatings decreased with increasing the aging time unlike the uncoated Mg-6 wt%Al alloy showing the peak micro-hardness and the best wear property after aging for 16 h. However, the coatings on Mg-6 wt%Al alloy peak-aged for 16h revealed the best corrosion resistance in 3.5% NaCl solution, which was explained based on the microstructural characteristics.
Effect of ECAP on Microstructure of SiC<sub>w</sub>/6061Al Composites Produced by Powder Metallurgy
장시영,Chang, Si-Young Korean Powder Metallurgy Institute 2002 한국분말재료학회지 (KPMI) Vol.9 No.1
The 6061 Al alloy based composites reinforced with 10 vol% SiC whiskers were prepared by powder metallurgy with the powders having the different sizes, i.e. < $30{\mu}m$ and > $30{\mu}m$ The composites were subjected to equal channel angular pressing (ECAP) at various conditions and the microstructural changes during ECAP were examined In the composites SiC whiskers were clustered and randomly aligned. The clusters were relatively well distributed in the composite with the smaller initial powder size. After ECAP, the clusters were aligned parallel to flow direction and became smaller. In addition, the shape of clusters was changed from irregular to round. The microstructure of the ECAPed samples were compared with those of the conventionally hot-extruded composites. The uniform microstructure and enhanced microhardness could be obtained by using the powders having the smaller size, decreasing ECAP temperature and repeating ECAP.