• Economic and Environmental Geology
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• v.35 no.2
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• pp.103-112
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• 2002

Despite the ecological importance of potentially phytotoxic $Al_{13}$-tridecamer and its formation in the simulated condition, it was not recognized in the natural soil environment. Here we performed thermodynamic calculations to examine the stability condition of $Al_{13}$-tridecamer based on the solubility of AI in the Bo horizon of Andisols, Jeju Island, dominantly composed of AI-containing solid phases such as $Al(OH)_{3}$, proto-imogolite and/or imogolite. We have found that $Al(OH)_{3}$, proto-imogolite and/or imogolite may control Al solubility in the moderate acid condition. It means that AI total activity of the soil solution equilibrated with these solid phases ranges from $10^{-6}$ ~ $10^{-8}$M in the pH 5 to 7. Calculations based on the thermodynamic data strongly indicate that the formation of $Al_{13}$-tridecamer closely related to the total activity of AI in the system. For example, for the formation of $Al_{13}$-tridecamer of $10^{-5}$M, Al total activity of $3{\times}10^{-3}$M are needed at pH 4, and $2{\times}10^{-5}$M in the pH 5 to 7. Therefore, this research and the thermodynamic consideration suggest strongly that $Al_{13}$-tridecamer should be negligible in natural soils, especially Andisols and Spodosols, These mainly contain $Al(OH)_{3}$, proto-imogolite and/or imogolite, which could prevent the formation of $Al_{13}$-tridecamer by controlling the AI total activity low. It means that the toxicity of $Al_{13}$-tridecamer with the increase of soil acidification may be considered to be definitely low.

• 발명특허
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• v.7 no.2 s.72
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• pp.57-57
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• 1982

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.227-236
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• 2005

Hydrothermal tourmaline occurs as aggregates or dissemination in the diaspore nodule from an aluminum-rich clay deposit, Milyang, southeastern Korea. Most crystals of tourmaline show complex textures that are finely zoned. The fine-scale chemical zonation of hydrothermal tourmaline reflects the fluctuation conditions that would be expected from fluid mixing in open systems. Oscillatory chemical zoning in tourmaline formed and showed similar patterns, regardless of its crystallographic directions. Mg was enriched in the early stage of crystal growth while Fe was enriched in the later stage, with fluctuations of the ratio of Fe to Mg. Chemical analysis, BSE images, and X-ray compositional maps confirm that the oscillatory Boning in tourmaline is exclusively controlled by the variations of Fe and Mg contents, but the contribution of boron to the zonation is insignificant. The fact that tourmaline altered to diaspore and dickite indicates that tourmaline was unstable with respect to these aluminous minerals as the B, Fe, and Mg activities decreased. Therefore, the aluminum activity may control the stability of tourmaline in the hydrothermal system.

• The Monthly Technology and Standards
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• s.6
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• pp.44-46
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• 2002

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.287-291
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• 2005

Pop-in deformation phenomena in aluminum was studied. Whether a pop-in occurs or not depended on the surface polishing method. Pop-in did not occur in aluminum which was polished mechanically, while it occurred in aluminum which was polished electrically. When pop-in occurred, elastic deformation preceded. Pop-in mechanism based on dislocation activity was suggested. Suggested mechanism was consistent with the result of microstructure analysis by Focused Ion Beam polisher (FIB) and Transmission Electron Microscopy (TEM).

• Analytical Science and Technology
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• v.6 no.2
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• pp.167-180
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• 1993

The effects of coating variables on the formation of aluminide coating layer with good oxidation resistance on the strongest hot-forged superalloy in the world, KM 1557 developed at KIST by pack cementation process were studied. Pack aluminizing were performed by high-activity process with pure aluminium powders and by low-activity process with codep powders. For high-activity process, Al deposition rate, growth rate of coating layer, and cross-sectional microstructures were influenced by the species and additive amounts of activators and the additive amounts of pure aluminium powders. For low-activity process, Al deposition rate, growth rate of coating layer, and the cross-sectional microstructures were not influenced by the species but additive amounts of activators. Surface structures of coating layer were influenced by the species of activators. Regardless of aluminium activity, Al deposition rate was proportional to the square root of time and parabolic rate constants were different with the species of activators. The activation energy for deposition of aluminium was different with the species of activators for high-activity process. Regardless of the species of activators, the activation energy for deposition of aluminium was 12~14 Kcal/mole for low-activity process.

• KASI NEWSLETTER
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• s.16
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• pp.1-4
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• 1999

소백산 천문대 61cm 망원경 이전/소백산천문대 신축 연구관리동 완공/우리별3호 촬영/보현산 1.8m 망원경 주경 알루미늄 증착 및 망원경 시스템 점검/후반기 지역천문대 관측 계획/IAU 심포지움197 소식/경영정보시스템 본격가동/태양활동예보

• 선박안전기술공단 소식
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• s.2
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• pp.4-4
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• 2006

"그림으로 보는 알기 쉬운 기관 점검 · 정비" 책자 발간/ "알루미늄 합금제 어선의 선형개발을 위한 해외사례 조사"/ 2종 스테인리스축 방식용 AL경량합금제 실용화 방안연구

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.4
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• pp.165-175
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• 1997

This study qualitatively reviewed effect of the height of loading and the ratio of penetration on. the characteristics of deformation of cellular bulkhead by performing a model test of embedded steel plate cellular bulkhead which had different loading height and penetration ratio. And we also examined the effect of the loading height upon the shear behavior by performing two-dimensional model test making use of aluminum rods for a filler. Besides, test results and theoretical values based on Hansen's earth pressure theory were compared and reviewed. In consequence, it was ascertained that the yield moment of cells depended on the height of loading and the ratio of penetration, and the slip surface was located on the lower area of a cell interior according as the height of loading becomes lower. The theoretical consideration which was based on the theory of earth pressure proposed by Hansen revealed that the test results accorded with the theoretical values to some degree, and the same results were derived about the location change of the slip surface.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.231-235
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• 1993

광석으로부터 생산된 금속의 양은 문명이 시작되고 부터 1750년대까지 전세계에서 약 2500만ton정도가 생산되었다고 추정되고 있다. 그러나 Fig. 1에서 보이는 것처럼 1980년대에는 그 생산량이 1년 간에 약 5억8천만ton이 되었고, 실제로 10년 간에 약 58억ton이 소비되기에 이르렀다. 그러나 금속자원은 무한히 있는 것이 아니고, 채굴기술에도 한계가 있기 때문에 머지않아 금속자원은 고갈해 버릴 것이다. 금속자원이 앞으로 어느 정도 기간까지 채굴이 가능할까 하는 것은 납이 22년, 아연이 41년, 구리가 53년, 철, 알루미늄이 230년 정도라고 추정되고 있다. 새로운 거대한 광맥이라도 발견된다면 이런 DATA는 다소 바뀔 수도 있겠으나, 앞으로 발전도상국들의 적극적인 경제활동으로 이러한 금속자원은 더욱 많이 사용될 것이며, 따라서 이와 같은 예상은 더욱 단축될 것이다.(중략)