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윤영섭,윤덕용 대한금속재료학회(대한금속학회) 1977 대한금속·재료학회지 Vol.15 No.2
The effect of cold working and subsequent annealing on mechanical properties of W-Ni-Fe heavy alloy has been studied. The specimen composition was 90W-5Ni-5Fe by weight percent. The specimens were prepared by usual powder metallurgy techniques and sintered in liquid phase at 1460℃ for 30 minutes in hydrogen atmosphere. The specimens were then cold worked up to 60% by rolling. The observed UTS increases with cold working from about 94㎏/㎟ to 143㎏/㎟ at 50% deformation. The elongation decreases sharply from 20% to about 2% at 15% deformation. While the microhardness of the tungsten grains increases steadily with degree of cold work, the micro hardness of the matrix appears to increase rapidly with deformation initially. It is therefore suggested that at relatively small deformation the matrix phase work hardens rapidly and affects the deformation behavior of the composite alloy. The alloy specimen cold worked to 50% was annealed at temperatures from 400℃ to 1000℃ for an hour in hydrogen atmosphere and the mechanical properties were measured. Annealing of the cold worked specimen at 400˚increases UTS to 160㎏/㎟ from 143㎏/㎟ for the unannealed specimen, and with increasing annealing temperatures UTS decreases. The elongation begins to increase with annealing temperature at 800℃ and rises sharply to 4% at 1000℃. The microhardness of the tungsten grains remains unchanged with annealing temperature up to 600℃ and from 800℃ begins to decrease slowly. The microhardness of the matrix on the other hand shows maximum after annealing at 400℃ and decreases subsequently with higher annealing temperatures. These observations indicate that the increase of the UTS after annealing at 400℃ is largely due to the increased strength of the matrix. This increase in matrix strength with annealing is most likely caused by some, kind of precipitation hardening which is probably accelerated by cold work. The observed changes of mechanical properties at higher annealing temperatures are attributed mainly to the recovery and recrystallization of the matrix phase.
SEPOX (selective poly oxidation) process에서 Si-buffer layer에 발생하는 pinhole 현상에 대한 연구
윤영섭 대한전자공학회 1996 전자공학회논문지-A Vol.33 No.6
We propose a mechanism for the formation of pinholes in the Si-buffer layer, through the observations with varying the process- and structure variables in the SEPOX (selective poly-oxidation) process, an isolation method for sub-u DRAMs. Pinholes are formed through the accumulation of Si vacancies generated by the oxidation of Si, in which Si atoms leave the sites (vacancies) at the Si/SiO$_{2}$ interfaces and diffuse into the oxide to be oxidized near interface. In the course of the accumulation of Si-vacancies, the stress induced in the Si-buffer layer affects the migration of vacancies to result in the final size and distribution of pinholes. This paper may be, to our knowledge, the first report about the oxidation-induced pinhole in the Si/SiO$_{2}$ system.
Aspidosperma로부터의 Spegazzinine과 Spegazzinidine의 分離 및 그 確認에 關한 硏究
尹英燮 이화여자대학교 한국문화연구원 1967 韓國文化硏究院 論叢 Vol.10 No.-
Spegazzinine andspegazzinidine, the new Alkaloid from Aspidosperma Chakensis spegazzini, may be used as a respiratory stimulant, a tonic, and these compounds has been shown to possess Aspidospermine type structure(Ⅰ). In this paper the column chromatography has been used for the isolation and separation of these compounds, and the spectrometry has applied to the identification of this complicated class of Alkaloid.
尹英燮 이화여자대학교 한국문화연구원 1966 韓國文化硏究院 論叢 Vol.8 No.-
The complex metal hydrides are among the recently developed inorganic compounds for which wide application in the organic field has been found. Among these, hydrides, lithium aluminum hydrides, (referred to as LAH), is an extremely powerful reducing agent. It reacts violently with water causing the liberation of hydrogen and decomposition of any water soluble compound. It reacts readily and, in many cases quantitatively, with substances soluble in ether such as diethyl ether and tetrahydro furan. Under conditions similar to those used with the Grignard reagent. Functional groups which have resisted other chemical reactions have successfully been reduced with LAH. The action of LAH is often highly specific, yielding products of a high degree of purity due to the absence of side reactions, condensations and cleavages often encountered with other reducing agents. The author has discussed the effect of LAH on organic compounds with special emphasis on its powerful reducing action.