• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.5743-5747
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• 2015

In this study, Fe-based bulk amorphous alloy powder manufactured using gas atomization fabrication was used for laser welding. the fracture behavior of welding layer were analyzed. Tensile test results show that the destruction occurred immediately after the elastic deformation, After plastic deformation of the substrate, the destruction occurred. The actual maximum tensile strength of the welding layer and the substrate are 959.9MPa and 220.4MPa. welding layer were each $485.5{\pm}21$ and $197.4{\pm}14$ to the substrate and the actual microhardness, The welding layer has very high hardness. The welding layer showed a very weak fine acicular structure. The base material was shown in the micro structure appear a coarse grain. SEM observations of the fracture after the tensile test. Fracture morphology of the base metal and the welding layer showed ductile fracture and brittle fracture, respectively.

• Proceedings of the KWS Conference
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• 1994.10a
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• pp.177-179
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• 1994

• Proceedings of the KWS Conference
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• 1994.05a
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• pp.69-71
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• 1994

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.183-185
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• 1996

• The Korean Journal of Quaternary Research
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• v.3 no.1
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• pp.69-85
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• 1989

The depositional environments of the Pyung-Ahn Group sedimentary rocks, Jeongseon-Kun, Kangweondo, Korea are investigated. The environments are understood to be characteristic transitional from a typical shallow marine to a typical continental environment. Such transitional conditions are also understood in various parts of Quaternary and modern environment on the earth. In particular, the absence of detrital feldspar sand grains in the Manhang and Keumcheon Formation Sandstone body is described firstly in Korea, and the fact and possible mechanism are discussed.

• Proceedings of the KWS Conference
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• 1995.04a
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• pp.84-86
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• 1995

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.1
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• pp.68-75
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• 2002

Stellite 12 alloy-powders were overlaid on 410 stainless steel valve seat by plasma transferred arc(PTA)process. Variation of microstructure and hardness of overlaid deposit with aging time at $750^{\circ}C$ was investigated. The deposit showed hypoeutectic microstructure, which was consisting of primary cobalt dendrite and networked $M_{7}C_{3}$type eutectic carbides. After aging new M_{23}C_{6}$ carbide was formed by the partial decomposition of $M_7C_3$ type eutectic carbides and finely dispersed $M_{23}C_6$ type carbides were also precipitated in the matrix. Hardness of the deposit was increased with increase of aging time at $750^{\circ}C$ and showed maximum value at 35hours. After showing maximum value, it was fallen down again at 70hours because of overaging. The increase of hardness in aging is ascribed to the formation of new stable $M_{23}C_6$ type carbide by the partial decomposition of $M_7C_3$ type eutectic carbides and also precipitation of finely dispersed $M_{23}C_6$ carbides in matrix.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.151-156
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• 1999

싱가폴등 경쟁력 있는 아시아 국가에서 이미 정책 육성 된바있는 아파트형 공장은 9층 높이 규모로 도심이나 도심근교의 경제적 집약적 중소규모 육성정책의 일환으로 국내에서도 94년도 입주되기 시작하여 98년도 현재 전국적으로 67개소에 수많은 업체들이 입주해 있으며 이중 약 50%는 S 시에 집중되어 있다. (중략)

• Digital Contents
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• no.3 s.34
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• pp.68-99
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• 1996

한국정보산업연합회에서는 '96년 1월 30일 전경련회관 3층 대회의실에서 올해의 정보화 추진 및 정보산업 육성정책 내용과 이와 관련한 장 단 기 정책방향에 관한 설명을 청취하고 이에 대한 업계의 의견을 개진하면서 기업의 사업방향과 대 정부 협조방안을 모색하는 기회를 마련하였다. '96년도 각 부처별 정보화 정책과 정보산업육성시책을 종합적으로 파악할 수 있으며 또한 자사의 사업수립과 경영활동에 큰 도움이 될 것으로 보며, 본고에서는 정보화 정책 포럼(정보통신부, 초고속정보통신망구축기획단, 교육부, 국방부, 건설교통부, 총무처, 통상산업부 내무부) 내용중 '96년도 사업계획을 발췌하여 게재하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.121-127
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• 2018

A system for diagnosing surface defects of long and large pipe inner overlay welds, 1m in diameter and 6m in length, was developed using a Liquid Penetrant Test (PT). First, CATIA was used to model all major units and PT machines in 3-dimensions. They were used for structural strength analysis and strain analysis, and to check the motion interference phenomenon of each unit to produce two-dimensional production drawings. Structural strength analysis and deformation analysis using the ANSYS results in a maximum equivalent stress of 44.901 MPa, which is less than the yield tensile strength of SS400 (200 MPa), a material of the PT Machine. An examination of the performance of the developed equipment revealed a maximum travel speed of 7.2 m/min., maximum rotational speed of 9 rpm, repeatable position accuracy of 1.2 mm, and inspection speed of $1.65m^2/min$. The results of the automatic PT-inspection system developed to check for surface defects, such as cracks, porosity, and undercut, were in accordance with the method of ASME SEC. V&VIII. In addition, the results of corrosion testing of the overlay weld layer in accordance with the ferric chloride fitting test by the method of ASME G48-11 indicated that the weight loss was $0.3g/m^2$, and met the specifications. Furthermore, the chemical composition of the overlay welds was analyzed according to the method described in ASTM A375-14, and all components met the specifications.