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Si<sub>3</sub>N<sub>4</sub>/Ti와 Si<sub>3</sub>N<sub>4</sub>/TiAl합금의 계면반응 및 확산 거동
최광수,김선진,이지은,박준식,이종원,Choi, Kwang Su,Kim, Sun Jin,Lee, Ji Eun,Park, Joon Sik,Lee, Jong Won 한국재료학회 2017 한국재료학회지 Vol.27 No.11
$Si_3N_4$와 Ti 또는 TiAl 합금을 $900^{\circ}C$에서 확산쌍을 제조하여 분석하고, 확산층의 분석을 통하여 생성된 층마다의 조성을 분석하여 각 원소들의 확산 경로 및 속도를 비교 하였다. $Si_3N_4/Ti$의 확산 쌍의 확산 경로는 $Si_3N_4/Ti_5Si_3+TiN/TiN/Ti$로 나타났고, Ti 측면에서 TiN층이 생성 되었음으로 N의 확산 속도가 Si 보다 빠름을 알 수 있었다. $Si_3N_4/TiAl$ 합금의 확산쌍은 $Si_3N_4/Ti$ 사이의 확산쌍과는 다르게 Si, N, Ti, Al 의 각 원소 마다의 확산 속도 차이로 인하여 확산 경로는 $Si_3N_4/TiN(Al)/Ti_3Al/TiAl$ 상으로 나타났다. 상태도를 통하여 생성된 확산쌍의 확산경로를 파악한 결과, 확산경로의 요구사항을 모두 만족하였다. $Si_3N_4/Ti$ 확산에서 Ti를 이용한 적분확산 계수는 $Ti_5Si_3$, TiN에서 $2.18{\times}10^{-16}m^2/sec$, $2.19{\times}10^{-16}m^2/sec$, $Si_3N_4/TiAl$ 확산 쌍에서 Ti를 이용한 적분확산 계수는 각각 TiN(Al) 상에서 $2.88{\times}10^{-16}m^2/sec$, $Ti_3Al$ 상에서 $1.48{\times}10^{-15}m^2/sec$으로 나타났다. 본 연구는 $Si_3N_4$와 Ti 및 TiAl의 계면 반응을 분석한 결과로서 $Si_3N_4$ 상을 이용한 확산반응의 기초자료로 사용될 수 있을 것으로 사료된다. $Si_3N_4$ is a ceramic material attracting attention in many fields because of its excellent abrasion resistance. In addition, Ti and TiAl alloys are metals used in a variety of high temperature environments, and have attracted much attention because of their high strength and high melting points. Therefore, study of the interface reaction between $Si_3N_4/Ti$ and $Si_3N_4/TiAl$ can be a useful practice to identify phase selection and diffusion control. In this study, $Si_3N_4/Ti_5Si_3+TiN/TiN/Ti$ diffusing pairs were formed in the $Si_3N_4/Ti$ interfacial reaction and $Si_3N_4/TiN(Al)/Ti_3Al/TiAl$ diffusion pathway was identified in the $Si_3N_4/TiAl$ interfacial reaction. The diffusion layers of the interface reactions were identified and, to investigate the kinetics of the diffusion layer, the integrated diffusion coefficients were estimated.
최광수(Kwang-Soo Choi),정두용(Doo-Yong Jung),김재형(Jae-Hyung Kim),이수원(Su-Won Lee),원충연(Chung-Yuen Won),정용채(Yong-Chae Jung) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-
In this paper, we have proposed a novel zero-voltage -switching (ZVS) soft-switching H-bridge inverter. Because the conventional H-Bridge inverter generates switching losses at turn on and off, the efficiency is reduced. The proposed inverter operates ZVS switching using an auxiliary switch and resonant circuit to improve the efficiency. in the DC-DC converter stage, it can reduce not only switching loss but also capacity and size of passive devices due to the resonant elements. DC-AC inverter stage supplies load with energy through the ZVS operation of 4 switches. A detail mode analysis of operating is in presented. We have presented the inverter topology, principle of operation and simulation results obtained from the PSIM simulator.
마이크로 벤딩 광섬유센서를 이용한 축중량 측정센서 개발을 위한 기초연구
최준성 ( Choi Jun-sung ),이규완 ( Lee Kyu-wan ),조병완 ( Jo Byung-wan ),최광수 ( Choi Kwang-su ),오영국 ( Oh Yoong-kok ) 한국구조물진단유지관리공학회 2007 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.11 No.1
Recent increased freight traffic and vehicles require weigh-in-motion(WIM) system to maintain road and manage traffic efficiently. In this paper, in-pavement WIM system using microbending(M/B) sensor is proposed and a preliminary study is performed. A pressure test is carried out to identify M/B sensor response character using 1 axle compression tester. It is possible to apply the M/B sensor on WIM system, and a supplementary research must be performed to secure durability and stability of WIM sensor package.
마이크로 벤딩 광섬유센서를 이용한 축중량 측정센서 개발을 위한 기초연구
최준성(Choi Jun-Sung),이규완(Lee Kyu-Wan),조병완(Jo Byung-Wan),최광수(Choi Kwang-Su),오영국(Oh Yoong-Kok) 한국구조물진단유지관리학회 2007 한국구조물진단학회 학술발표회논문집 Vol.11 No.1
Recent increased freight traffic and vehicles require weigh-in-motion(WIM) system to maintain road and manage traffic efficiently. In this paper, in-pavement WIM system using microbending(M/B) sensor is proposed and a preliminary study is performed. A pressure test is carried out to identify M/B sensor response character using 1 axle compression tester. It is possible to apply the M/B sensor on WIM system, and a supplementary research must be performed to secure durability and stability of WIM sensor package.
수평자장 하에서 성장된 CZ 실리콘 단결정의 산소 분포 및 석출거동
김경민,최광수,이문희,Kim, Kyeong-Min,Choi, Kwang-Su,P. Smetana,T.H. Strudwick,Lee, Mun-Hui 한국재료학회 1992 한국재료학회지 Vol.2 No.2
수평자장을 건 Czochralski(HMCZ) 방법으로 자장강도(B)와 도가니 회전속도(C)가 실리콘 단결정의 산소편석에 미치는 영향에 대하여 연구하였다. B=2, 3, 4kG와 C=4-15rpm에서 <100> 방향으로 성장시킨 57mm 직경의 단결정들 내의 산소분포는 대체로 축을 따라서 불균일하였고 톱니모양을 나타내었다. 종래의 CZ 방법과 비교할 때, 이러한 산소분포의 불균일성은 위 강도의 수평자장이 결정성장계면으로의 산소전달에 불안정한 요소로 작용했음을 나타낸다고 볼 수 있다. 반면에 C의 증가는 산소분포의 불균일성의 약화와 산소농도의 전반적인 증가를 유도하였다. 이 결과를 토대로 B=2kG에서 27-36ppma인 산소분포를 가진 단결정이 프로그램된 C에 의해서 얻어졌다. 소자제조공정을 모의한 열처리 과정에서 HMCZ 실리콘의 산소석출은 종래의 CZ 실리콘의 산소석출에 비해서 상대적으로 불균일하였고, as-grown 상태에서의 고르지 못한 HMCZ 실리콘의 산소분포가 주요 원인임이 밝혀졌다. Oxygen segregation in horizontal-magnetic-field-applied Czochralski (HMCZ) silicon crystals has been studied as a function of magnetic field strength (B) and crucible rotation rate (C). Along the axis of 57mm din. <100> crystals grown under B=2, 3, 4 kG and C=4-15rpm, the oxygen distribution was usually saw-tooth shaped and fluctuated unevenly. Compared to the conventional CZ method, this result seems to indicate that the horizontal magnetic field, at levels used in the present experiment, had a destabilizing influence on oxygen transport to the growth interface. On the other hand, as C increased, the oxygen fluctuation lessened, and [0] increased overall. At B=2 kG, an oxygen profile in a level of 27-36 ppma was achieved by a programmed ramp of C. Oxygen precipitation behavior of the HMCZ silicon during a simulated device manufacturing process was compared and found to be inferior to that of typical CZ silicon. The uneven oxygen profile in the as-grown state was identified as the major source of poor precipitation uniformity in the HMCZ silicon.
토양 속 박테리아가 지하매설 X65 배관의 미생물 부식 거동에 미치는 영향
최병학,한성희,김대현,김우식,김철만,최광수,Choe, Byung Hak,Han, Sung Hee,Kim, Dae Hyun,Kim, Woosik,Kim, Cheolman,Choi, Kwang Su 한국재료학회 2022 한국재료학회지 Vol.32 No.3
Microbiologically Influenced Corrosion (MIC) occurring in underground buried pipes of API 5L X65 steel was investigated. MIC is a corrosion phenomenon caused by microorganisms in soil; it affects steel materials in wet atmosphere. The microstructure and mechanical properties resulting from MIC were analyzed by OM, SEM/EDS, and mapping. Corrosion of pipe cross section was composed of ① surface film, ② iron oxide, and ③ surface/internal microbial corrosive by-product similar to surface corrosion pattern. The surface film is an area where concentrations of C/O components are on average 65 %/16 %; the main components of Fe Oxide were measured and found to be 48Fe-42O. The MIC area is divided into surface and inner areas, where high concentrations of N of 6 %/5 % are detected, respectively, in addition to the C/O component. The high concentration of C/O components observed on pipe surfaces and cross sections is considered to be MIC due to the various bacteria present. It is assumed that this is related to the heat-shrinkable sheet, which is a corrosion-resistant coating layer that becomes the MIC by-product component. The MIC generated on the pipe surface and cross section is inferred to have a high concentration of N components. High concentrations of N components occur frequently on surface and inner regions; these regions were investigated and Na/Mg/Ca basic substances were found to have accumulated as well. Therefore, it is presumed that the corrosion of buried pipes is due to the MIC of the NRB (nitrate reducing bacteria) reaction in the soil.