액체 An-In, Al-Sn, Al-Ga 계합금의 열역학적 성질

이용근 대한금속재료학회(대한금속학회) 1970 대한금속·재료학회지 Vol.8 No.2

金屬溶液의 熱力學的性質은 冶金理論의 基礎를 이루우고 있으므로, Al冶金의 基礎的硏究로서, 液體 Al溶液의 熱力學的 硏究를 한 結果中에서 Al-In, Al-Sn 및 Al-Ga系에 대한 特性을 論한다. 濃淡電地에 의한 그 起電力을 全組成範圍에 선하여 各各 700℃에서 94℃, 680℃에서 860℃ 및 680℃에서 820℃의 溫度範團에서 測定하고, 이것에 의거하여 Al, In, Sn 및 Ga의 各系에 있어서의 活量과 다른 熱力學的性質을 算出하여, 그 結果를 考察하였다. 이 中에서 Al-In系에는 二液相이 있어서 그 範圍을 起電力의 測定値에서 決定하였다. Al-In系의 成分의 活量은 Raoult의 法則에서 크게 正으로 偏倚하고, 溫度가 높을 수록 Raoult의 法則에 接近하여, 二液相內에서는 組成에 關係 없이 定溫度에서는 일정한 活量을 나타낸다. Al-Sn系에서는 Raoult의 法則에서 상당히 正으로 偏倚하며, Al-Ga系에서는 상당히 잘 따르고 있다. 그리하여 Al-In系는 比正則溶液, Al-Sn系는 sub-regular solution 및 Al-Ga系는 regular solution에 가까움을 알 수 있었다. 이 系들의 無限稀溥溶液에서의 活量係數는 γ˚은 Al-In系는 700℃에서 Al, In 各各 11.3, 13.2이며, Al-Sn系에서는 800℃에서 各各 4.05, 7, 11 및 Al-Ga系에서는 700℃에서 各各 1.15, 1.27을 얻었다. 한편 統計熱力學으로도 model 을 適用하여, 古典熱力學에 의한 結果와 比較考察하였다. 즉 Al-In系에 대해서는 model과 二液相境界線을 써서 活量을 算出하고, Al-Sn, Al-Ga의 兩系에 대해서는 各系의 熱力學的 過剩量을 算出하였다. 그리고 quasi-chemical의 近似式을 써서 3系에 있어서의 原子相互作用 energy와 short-range order parameter를 算出하고, 또 3系에 있어서의 各成分間의 self-interaction parameter도 算出해서, 이것들의 系의 巨視的性質과 微視的性質을 比較考察하여 서로 一致함을 알았다.

중금속에 의한 환경오염의 간이분석법

李龍根,黃圭子 연세대학교 자연과학연구소 1978 學術論文集 Vol.2 No.-

1-(2-pyridylazo)-2-naphthol(PNA)을 포함한 겔 粒子를 체운 分析컬럼을 사용하여 카드뮴 (Ⅱ), 코발트 (Ⅱ), 구리 (Ⅱ), 납 (Ⅱ), 및 亞鉛 (Ⅱ)등의 重金屬이온들을 ppm이하의 濃度까지 測定하였다. 重金屬이온을 포함한 試料水를 分析컬럼에 흘리면 각 金屬 PAN 킬레이트(Metal panate)들의 생성으로 인하여 겔粒子는 노란 색으로부터 붉은 색 또는 청자색으로 변하며 變色帶의 길이는 컬럼에 흘린 용액속의 重金屬이온의 濃度에 따라 比例되었다. 0.01% PAN겔의 分析컬럼으로 試料水를 0.2ml/min의 流速으로 흘리므로서 0.2~4.0ppm의 重金屬이온(납으로 환산된 농도)을 簡便迅速하게 同時測定할 수 있고 分析컬럼속의 0.01% PAN겔粒子는 冷暗所에서 보관하면 적어도 12개월까지는 안전하며 metal panate는 3M鹽酸으로 逆推出되므로 樹脂粒子를 再生시킬 수 있었다. 이 分析法은 몇몇 實地 試料水에 應用하여 原子吸光分析法의 測定値와 비교하고 回收實驗한 결과 本法은 一般環境水에도 適用할 수 있었다. Heavy metals such as cadmium(Ⅱ), cobalt(Ⅱ), copper(Ⅱ), lead(Ⅱ), and zinc(Ⅱ) were determined at sub-ppm level by using an analytical column packed with gel beads containing 1-(2-pyridylazo)-2-naphthol(PAN). The beads turned from bright yellow to ping or violet when the sample solution containing the these heavy metals were passed through the analytical column at pH 10. The length of colored zone was proportional to the amount of heavy metals in sample solution. With 0.01% PAN gel, 0.2~4.0 ppm of heavy metals (as lead) could be determined in the sample solution at a flow rate of 0.2ml/min. Analytical column packed with 0.01% PAN gel beads could be stored freshly for at least twelve months in a refrigerator and metal panates absorbed on the analytical column could be back-extracted from the resin beads by passing 3M hydrochloric acid. The used resin beads could be re-used repeatedly. This method was applied for analyzing the heavy metals of practical samples such as sea water, river water, industrial effluent and tap water, and it was found that the results of the present method was in agreement with that of atomic absorption spectrophotometric technique. Therefore, the method could be used in the field for samples of environmental origin.

전자계약의 체결에 따른 법리적인 문제점에 관한 연구

이용근,박종석 中央大學校附設 國際貿易物流硏究所 2002 國際貿易物流硏究論叢 Vol.9 No.-

信用狀 詐欺에 대한 Fraud Rule 適用의 問題點과 對應方案에 관한 硏究

李鎔根,韓載泌 中央大學校 1996 國際貿易硏究論叢 Vol.3 No.-

레진강화형 글라스아이오노머의 2 축 굽힘강도

이용근,임미경,구대회,이정식 大韓齒科保存學會 1997 Restorative Dentistry & Endodontics Vol.22 No.2

Resin-modified glass ionomers were introduced in 1988 to overcome the problems of moisture sensitivity and low early mechanical strengths of the conventional glass ionomers, and to maintain their clinical advantages. The purpose of this study was to evaluate the bi-axial fracture strength of four resin-modified glass-ionomers(Fuji II LC, Vitremer, Dyract, VstiGlass), one resin composite material(Z-100), and one conventional glass-ionomer(Fuji II). Three specimens of each material and shade combination were made according to the manufacturers' instructions. Materials were condensed into metal mold with a diameter of 10mm and a thickness of 2.0mm and pressed between two glass plates. Resin-modified glass ionomers were polymerized using a Visilux II light curing unit by irradiating for 60 seconds from both sides, and conventional glass ionomer was cured chemically. After specimens were removed from the molds, surfaces were polished sequentially on wet sandpapers up to No. 699 silicone carbide paper. The specimens were thermocycled for 2,000 cycles between 5℃ and 55℃ distilled water. After thermocycling, bi-axial fracture strengths were measured using a compressive-tensile tester(Zwick 1456 Z020, Germany) with the cross head speed of 0.5mm/minute. The results were as follows: 1. Two factors of the kind and color of materials had a main effect on bi-axial fracture strength (p<0.01), and bi-axial fracture strength was influenced significantly by the kinds of materials (p<0.01). But there was no significant interaction between two variables of the kind and color of materials (p>0.05). 2. Comparing the mechanical properties of the materials, the elastic modulus of Z100 was higher than any other material, and there was no difference in the displacement at fracture among materials. The bi-axial fracture strength of Z100 was significantly higher than any other material, and that of resin-modified glass ionomers was significantly higher than that of conventional glass ionomer (p<0.05). 3. In the same material group, the color of material had little influence on the mechanical properties.

熔融알루미늄 二元合金의 混合熱

李容根 全北大學校 1976 論文集 Vol.18 No.-

The heats of mixing in the binary liquid aluminum alloys, Al-In, Al-Ga and Al-Ge systems were determined using an adiabatic calorimeter directly, and those of Al-Sn, Al-Zn, Al-Te and Al-Au systems were also determined by the electromotive force method, dew point method and distribution method indirectly. The values obtained were treated with ξ function^2), and the properties of these solutions have been observed based on the ξ functhons. As a result, it seems that Al-Zn system is a regular solution, Al-Ga, a regular soluton obeying quasi-chemical approach and Al-Ge, a sub-regular solution. The relations of the ξ function to the periodic law and to the equilibrium diagram in each system were discussed, and the short-range order parameters have also been derived using the heats of mixing in the Al-In and Al-Ga systems.

液體 Al-Zn, Al-Te系의 熱力學的 性質

李容根 全北大學校 1971 論文集 Vol.13 No.-

The liquid aluminum-zinc and -tellurium systems have been investigated by the dew point method for clarifying their thermodynamic properties. In this work, the dew point method has been improved so as to find out the dew point thermoanalytically and record it automatically. Consequently, the measuring operation is simpler, and that, the result is more accurate than that of ordinary one. The measurements were carried out over entire composition range for both systems, and in the temperature range 650°to 800℃ for the Al-Zn system and 700°to 920℃ for the Al-Te system. The activities of the components Al, Zn and Te of both systems have been derived using the messured data, and also calculated from quasichemical approach, regular solution theory and the heat of fusion of Al_2 Te_3. The interaction energies and short-range order parameters for the Al-Zn system have been calculated from quasichemical approach and the results are reasonable to compare with the classical thermodynamic properties.

大學生指導와 그 問題改善에 關한 硏究

李容根,張大雲,金武吉 全北大學校 學生生活硏究所 1976 學生生活硏究 Vol.4 No.-

사이버무역의 범위와 전개방향에 관한 연구

李鎔根 中央大學校附設 國際貿易物流硏究所 2000 國際貿易物流硏究論叢 Vol.6 No.-

서울市內 河川水 및 工場排水中의 銅含量

李龍根 연세대학교 대학원 1969 延世論叢 Vol.6 No.1

The analysis for the Copper contents of river water and industrial waste water in Seoul area has been carried out by the spectrophotometric method, from August, 1967 to July, 1998. The results show that the avarage copper contamination is found to be in the range of 0.11±0.01∼0.63±0.13 mg/l. The reason for this contamination is discussed in detail.