• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1996년도 특별강연 및 추계학술발표 개요집
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• pp.3-15
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• 1996

The formation of a thicker hard alloyed layer have been investigated on the surface of aluminum cast alloy (AC2B) by PTA overlaying process with Cr, Cu and Ni motel powders under the condition of overlaying current 125-200A. overlaying speed 150 mm/min and different powder feeding rate 5-20 g/min. In addition the characteristics of hardening and wear resistance of alloyed layer here been examined in relation to the microstructure of alloyed layer. Main results obtained were summarized as follows: 1) There was an optimum overlaying condition to get a good alloyed layer with smooth surface. This good layer became easy to be formed as increasing overlaying current and decreasing powder feeding rate under a constant overlaying speed. 2) Cu powder was the most superior one in metal powders used due to a wide optimum overlaying condition range, uniform hardness distribution of Hv250-350, good oar resistance and freedom from cracking in alloyed layer with fine hyper-eutectic structure. 3) On the contrary, irregular hardness distribution was usually obtained in Cr ar Ni alloyed layers of which hardness was increased as Cr or Ni contents and reached to maximum hardness of about Hv400-850 at about 60wt%cr or 40wt%Ni in alloyed layer. 4) Cracking occurred in Cr or Ni alloyed layers with higher hardness than Hv250-300 at mere than 20-25wt% of Cr or Ni contents in alloyed layer. Porosity was observed in all alloyed layers but decreased by usage of spherical powder with smooth surface.

• 미생물학회지
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• 제30권5호
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• pp.333-338
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• 1992

Saccharomyces cerevisiae 의 mother cell과 daughter cell 의 연결 부위의 원형질막 바로 안쪽에 존재하는 10-nm filament ring 은 세포형태 형성과정에 중요한 역할을 하리라 간주되나 그 명확한 생성기작과 기능은 밝혀지지 않았다. 본연구에서는 CDC12 유전자로부터 gene fusion technique 을 이용하여 CDC12 단백질을 만들고 이로부터 항체를 형성하였다. 이항체를 이용하여 10-nm filament ring 의 생성기작과 기능에 대하여 연구하였다. 그 결과 CDC12 단백질은 cell cycle 전주기동안 항상 정이되나 bud 가 나오기 바고 직전에 bud 가 나올 부위에 polymerization 되었다가 세포질분열 바로 직후에 unpolymerization 되며 cytoskeletal element 의 일종인 actin 과는 무관하게 행동하는 건이 밝혀졌다. 이러한 10-nm filament 는 bud 가 나올 부위의 올바른 선정과 세포질 분열에 중요한 역할을 하리라 간주된다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.53-54
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• 2013

Nano-multilayered CrAlSiN films consisting of crystalline CrN nanolayers and amorphous AlSiN nanolayers were deposited by cathodic arc plasma deposition. Their oxidation characteristics were studied between 600 and $1000^{\circ}C$ for up to 70 h in air. During their oxidation, the amorphous AlSiN nanolayers crystallized. The formed oxides consisted primarily of $Cr_2O_3$, ${\alpha}-Al_2O_3$, $SiO_2$. The outer $Al_2O_3$ layer formed by outward diffusion of Al ions. Simultaneously, an inner ($Al_2O_3$, $Cr_2O_3$)-mixed layer formed by the inward diffusion of oxygen ions. $SiO_2$ was present mainly in the lower part of the oxide layer due to its immobility. The CrAlSiN films displayed good oxidation resistance, owing to the formation of oxide crystallites of $Cr_2O_3$, ${\alpha}-Al_2O_3$, and amorphous $SiO_2$.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.112-113
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• 2013

Thin CrAlMgSiN films, whose composition were 30.6Cr-11.1Al-7.3Mg-1.2Si-49.8N (at.%), were deposited on steel substrates in a cathodic arc plasma deposition system. They consisted of alternating crystalline Cr-N and AlMgSiN nanolayers. After oxidation at $800^{\circ}C$ for 200 h in air, a thin oxide layer formed by outward diffusion of Cr, Mg, Al, Fe, and N, and inward diffusion of O ions. Silicon ions were relatively immobile at $800^{\circ}C$. After oxidation at $900^{\circ}C$ for 10 h in air, a thin $Cr_2O_3$ layer containing dissolved ions of Al, Mg, Si, and Fe formed. Silicon ions became mobile at $900^{\circ}C$. After oxidation at $900^{\circ}C$ for 50 h in air, a thin $SiO_2-rich$ layer formed underneath the thin $Cr_2O_3$ layer. The film displayed good oxidation resistance. The main factor that decreased the oxidation resistance of the film was the outward diffusion and subsequent oxidation of Fe at the sample surface, particularly along the coated sample edge.

• 자원리싸이클링
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• 제6권4호
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• pp.3-10
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• 1997

Electric are furnace dust (EAF dust) generated in steel production based on scrap melting is contained Zn and Fe about 25 and 30 percent by weight, respectively. From a metallurgical point of view, the dust could be regarded as a raw material for Zn and Fe source. To recover the Zn in the metal from EAF dust, many system are proposed such as Arc Plasma Furmace and Pb splasher method. In this study, to recover high purity Zn from Pb splasing alloy, Zn distillation is carried out at the temperature of 1123, 1173, 1223, 1273 K, the gas flow rate of 2.5, 5.0, 8.0 Ni/min and the distilling time of 10, 30, 60, 90 minutes. The main results obtained from this study are as follows:(1) The amount of evaporated Zn and its evaporating rate increased with increasing temperature, but purity of Zn decreased with increasing temperature. Optimum temperature range was found out to be between 1173∼1223K. (2) The amount of evaporated Zn and evaporation rate increased with increasing gas flow rate at a given temperature and distillation time. Gas flow rate has more influence over the amount of evaporated Zn and evaporation rate with increasing temperature.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.106-108
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• 2003

We fabricated Ni and Ni-W alloys for use as a substrate in YBCO coated conductor applications and evaluated the effect of W in Ni on texture, microstructure and surface morphology, and hardness of substrate. Pure Ni, Ni-2 at.％W, and Ni-5at.％W alloy substrates were prepared by plasma arc melting, cold rolling, and the recrystallization heat treatment at various temperature (700- 130$0^{\circ}C$). It was observed that Ni-W alloy substrates had stronger cube texture and maintained it at higher annealing temperature, compared to pure Ni substrate : The full-width at half- maximums of in-plane texture was 13.40$^{\circ}$ for Ni substrate and 4.42$^{\circ}$-5.57$^{\circ}$ for Ni-W substrate annealed at 100$0^{\circ}C$. In addition, it was observed that the Ni-W substrate had smaller grain size, shallower boundary depth, and higher hardness, compared to those of pure Ni substrate.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.55-58
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• 2003

We fabricated the textured Ni substrate and evaluated the effects of processing variables on microstructural evolution and texture transformation. Ni-rods as an initial specimen were prepared by two different methods, i.e., powder metallurgy(P/M) and plasma arc melting(PAM) The texture of the substrate was characterized by pole-figure and surface condition was evaluated by atomic force microscopy. It was observed that the texture of substrate made by P/M did not significantly varied with annealing temperature of 800~120$0^{\circ}C$ and the full-width at half-maximums (FWHM) of both in-plane and out-of-plane were 9$^{\circ}$~10$^{\circ}$. On the other hand, the texture of substrate made by PAM was more dependent on the annealing temperature and the FWHMs of in-plane texture was 9$^{\circ}$~13$^{\circ}$ at the temperature range. In addition, twin texture, (221)＜221＞, was formed as the temperature increased further. The grain size of substrate made by P/M was smaller than that made by PAM and this difference was correlated to the microstructure of initial specimens.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2006년도 추계학술발표회 초록집
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• pp.4-5
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• 2006

This paper represents modeling and optimization techniques for solar cell process on single-crystalline float zone (FZ) wafers with high efficiency; There were the four significant processes : i)emitter formation by diffusion, anti-reflection-coating (ARC) with silicon nitride using plasma-enhanced chemical vapor deposition (PECVD); iii)screen-printing for front and back metallization; and iv)contact formation by firing. In order to increase the performance of solar cells, the contact formation process is modeled and optimized. This paper utilizes the design of experiments (DOE) in contact formation to reduce process time, fabrication costs. The experiments were designed by using central composite design which is composed of $2^4$ factorial design augmented by 8 axial points with three center points. After contact formation process, the efficiency of the solar cell is modeled using neural networks. This model is used to analyse the characteristics of the process, and to optimize the process condition using genetic algorithms (GA). Finally, find optimal recipe for solar cell efficiency.

• 한국주조공학회지
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• 제22권2호
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• pp.75-81
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• 2002

The main objectives were to investigate the suitability of CaO crucible for melting TiAl alloys and to develop investment mold for investment casting of TiAl alloys. TiAl alloy specimen were prepared by plasma arc furnace under argon atmosphere. After melting of TiAl alloy using CaO crucible, the results showed that there is little contamination of oxygen in the TiAl bulk. Conventional vacuum induction furnaces can be readily adaptable to produce cast parts of TiAl without high skilled techniques. The determination of optical metallography and microhardness profiles in investment cast TiAl alloy rods has allowed the gradation of the relative thermal stability of the oxides examined. The molds used for the present study were $ZrO_2$, $Al_2O_3$, CaO stabilized $ZrO_2$ and $ZrSiO_4$. Even although high temperature of mold preheating, $Al_2O_3$ mold is a promising mold material for investment casting of TiAl alloys in terms of thermal stability, cost and handling strength. It is important to take thermal stability and preheating temperature of mold into consideration for investment casting of TiAl alloys.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.300-303
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• 2004

To fill the gap of films for metal-to-metal space High density plasma fluorinated silicate glass (HDP FSG) is used due to various advantages. However, FSG films can have critical drawbacks such as bonding issue of top metal at package, metal contamination, metal peel-off, and so on. These problems are generally caused by fluorine penetration out of FSG film. Hence, FSG capping layers such like SRO(Silicon Rich Oxide) are required to prevent flourine penetration. In this study, their characteristics and a capability to block fluorine penetration for various FSG capping layers are investigated through FTIR analysis. FTIR graphs of both SRO using ARC chamber and SiN show that clear Si-H bonds at $2175{\sim}2300cm^{-1}$. Thus, Si-H bond at $2175{\sim}2300cm^{-1}$ of FSG capping layers lays a key role to block fluorine penetration as well as dangling bond.