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웅성불임 및 왜성형질의 제초제저항성 들잔디(zoysia japonica Steud.)의 판별기술 개발
이범규(Bum kyu Lee),강홍규(Hong-Gyu Kang),라누리(Nu ri Ra),선현진(Hyeon-Jin Sun),권용익(Yong-Ik Kwon),송인자(In-Ja Song),김창기(Chang-Gi Kim),류태훈(Tae-Hun Ryu),박기웅(Kee Woong Park),이효연(Hyo-Yeon Lee) 충남대학교 농업과학연구소 2014 농업과학연구 Vol.41 No.3
The cultivation area and use of genetically modified (GM) crops have been increased continuously over the world. Concerns about the potential risks of GM crops are also increasing. Safe management for the development and production of GM crops is required according to Living Modified Organism Act in Korea. Planning about the methods, duration, and frequency of environmental monitoring is also required for commercial use of GM crops. GM Zoysia japonica Steud. (event name: JG21) expressing resistance to glufosinate-ammonium has been generated previously. By using gamma ray treatment to JG21 we also developed male sterility and dwarf Z. japonica (event name: JG21-MS). The objective of this study was to establish the monitoring system for environment release of JG21-MS. In this study we extracted RNA from JG21 and JG21-MS and conducted RAPD (random amplified polymorphic DNA) method to distinguish JG21 and JG21-MS.
최병학,이범규,장현수,전우일,박용성,임재균,이진희,박찬성,김진표,Choe, Byung Hak,Lee, Bum Gyu,Jang, Hyeon Su,Jeon, Woo Il,Park, Yong Sung,Lim, Jae Kyun,Lee, Jin Hee,Park, Chan Sung,Kim, Jin Pyo 한국재료학회 2017 한국재료학회지 Vol.27 No.3
The aim of this study is to consider the effect hydrogen on dezincification behavior of Cu-Zn alloys. The investigations include microstructural observations with scanning electron microscope and chemical composition analysis with energy dispersive spectrometer. The dezincification layer was found to occur in high pressure hydrogen atmosphere, not in air atmosphere. In addition, the layers penetrated into the inner side along the grain boundaries in the case of hydrogen condition. The shape of the dezincification layers was porous because of Zn dissolution from the ${\alpha}$ or ${\beta}$ phase. In the case of stress corrosion cracks formed in the Cu-Zn microstructure, the dezincification phenomenon with porous voids was also accompanied by grain boundary cracking.
최병학,이범규,장현수,박찬성,김진표,박남규,김청인,김보미,Choe, Byung Hak,Lee, Bum Gyu,Jang, Hyeon Su,Park, Chan Sung,Kim, Jin Pyo,Park, Nam Gyu,Kim, Cheong In,Kim, Bo Mi 한국재료학회 2017 한국재료학회지 Vol.27 No.8
This study investigated the surface pit corrosion of SS420J2 stainless steel accompanied by intergranular crack. To reveal the causes of surface pits and cracks, OM, SEM, and TEM analyses of the microstructures of the utilized SS420J2 were performed, as was simulated heat treatment. The intergranular cracks were found to have been induced by a grain boundary carbide of $(Cr,Fe)_{23}C_6$, which was identified by SEM/EDS and TEM diffraction analyses. The mechanism of grain boundary sensitization occurred at the position of the carbide, followed by its occurrence at the Cr depleted zone. The grain boundary carbide of $(Cr,Fe)_{23}C_6$ type precipitated during air cooling condition after a $1038^{\circ}C$ solid solution treatment. The carbide precipitate formation also accelerated at the band structure formed by cold working. Therefore, using manufacturing processes of cooling and cold working, it is difficult to protect SS420J2 stainless steel against surface pit corrosion. Several counter plans to fight pit corrosion by sensitization were suggested, involving alloying and manufacturing processes.
최병학,이범규,심종헌,고형순,조남철,이재성,박경균,김유찬,Choe, Byung Hak,Lee, Bum Gyu,Shim, Jong Hun,Go, Hyung Soon,Jo, Nam Chul,Lee, Jae Sung,Park, Kyung Gyun,Kim, Yu Chan 한국재료학회 2016 한국재료학회지 Vol.26 No.10
The aim of this paper is to consider the effect of the manufacturing processes on corrosion and centerline cracking of ancient bronze spoons. The ancient bronze spoons in question were made by several steps of forging, in reheated condition with cast ingots. The manufacturing method is similar to that of the modern spoons. The investigations include observations from light and scanning electron microscopes of the microstructure in terms of the crack propagation. Cracks in the centerline are caused by solute segregation in the center-line region; this solute is solidified in the final stage of bronze spoon manufacture. Centerline cracking is also caused by ${\alpha}$ phase segregation, accompanied by forged overlapping along the longitudinal direction of the spoons. A vertical stripe with cracks along the centerline of the spoon's width is formed by folding in the wrought process. The overlapping area causes crack propagation with severe corrosion on the spoon surfaces over a period of a thousand years. The failure mechanisms of ancient bronze spoons may be similar to that of modern spoons, and the estimation of the failure mechanisms of ancient spoons can be appropriate to determine failure causes for such modern spoons.
ADINA & WINLIFE 활용한 압력용기 용접부 피로파괴 해석
최병학(Byung Hak Choe),이범규(Bum Gyu Lee),심종헌(Jong Heon Shim),박찬성(Chan Sung Park),김진표(Jin Pyo Kim),박남규(Nam Gyu Park) 대한용접·접합학회 2016 대한용접·접합학회지 Vol.34 No.5
The aim of this study is to consider effect of weld elastic modulus on simulations of stress concentration and fatigue life for pressure vessel. The investigations include analysis with ADINA and WINLIFE softwares for whole body model about using condition of the boiler vessel. Values of weld elastic modulus were divided by 5 steps in butt weld area of the boiler vessel body. The stress concentration of the butt weld more was increased in case of higher elastic modulus of weld area because of higher difference of material properties between matrix and weld. It was concluded that the fatigue lives were decreased along increasing stress concentration due to high elastic modulus of weld. The matrix microstructure was estimated as pearlitic structure of α·ferrite and pearlite. And the microstructures of welds along 5 steps of elastic modulus were estimated as bainitic fine pearlite and martensite as increasing elastic modulus.