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金完培 中央大學校 食糧資源硏究所 1989 食糧資源硏究所 論文集 Vol.1 No.1
The edible oil industry in Korea has shown a relatively rapid growth rate recently as the demand for edible oil, due to the increase of per capita income, has been diversified. To analyze the market organization of edible oil industry, the dynamic structure-conduct-performance paradigmhas been adopted. The industry was highly concentrated, CR₄in 1986 was 0.59, comparing with the other food processing industries. In recent years, non-price competition such as product differentiation, product diversification, and diverse sales promotion, was more prevailing than the traditional price competition. As for the market performance, the excessive profitability was a major problem, while the stability, productivity, and progressiveness were relatively satisfactory. As the proportion of soybean oil, produced from imported soybean, has been increased rapidly, the self-sufficiency of raw materials for edible oil has been dropped remarkably, i.e., 14% in 1986. To achieve desirafle growth of the edible oil industry in Korea, (1) the increase of self sufficiency of raw materials, (2) the switch of market structure from a core oligopolistic type to a effective competition system were seemed to be required.
CaCl<sub>2</sub>-CaF<sub>2</sub>-CaO 용융염에서 YSZ 세라믹의 고온 안정성에 미치는 성형공정의 영향
김완배,권숙철,조수행,이종현,Kim, Wan-Bae,Kwon, Suk-Cheol,Cho, Soo-Haeng,Lee, Jong-Hyeon 한국재료학회 2020 한국재료학회지 Vol.30 No.4
The high-temperature stability of YSZ specimens fabricated by die pressure and cold isostatic press (CIP) is investigated in CaCl<sub>2</sub>-CaF<sub>2</sub>-CaO molten salt at 1,150 ℃. The experimental results are as follows: green density 46.7 % and 50.9 %; sintering density 93.3 % and 99.3 % for die press and CIP, respectively. YSZ foremd by CIP exhibits higher stability than YSZ formed by die press due to denseness dependency after high-temperature stability test. YSZ shows peaks mainly attributed to CaZrO<sub>3</sub>, with a small t-ZrO<sub>2</sub> peak, unlike the high-intensity tetragonal-ZrO<sub>2</sub> (t-ZrO<sub>2</sub>) peak observed for the asreceived specimen. The t-ZrO<sub>2</sub> phase of YSZ is likely stabilized by Y<sub>2</sub>O<sub>3</sub>, and the leaching of Y<sub>2</sub>O<sub>3</sub> results in phase transformation from t-ZrO<sub>2</sub> to m-ZrO<sub>2</sub>. CaZrO<sub>3</sub> likely forms from the reaction between CaO and m-ZrO<sub>2</sub>. As the exposure time increases, more CaZrO<sub>3</sub> is observed in the internal region of YSZ, which could be attributed to the inward diffusion of molten salt and outward diffusion of the stabilizer (Y<sub>2</sub>O<sub>3</sub>) through the pores. This results in greater susceptibility to phase transformation and CaZrO<sub>3</sub> formation. To use SOM anodes for the electroreduction of various metals, YSZ stability must be improved by adjusting the high-density in the forming process.