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마그네슘함량이 높은 니켈 Laterite광으로부터 습식공정에 의한 니켈과 코발트 회수
이만승 ( Man Seung Lee ),김상배 ( Sang Bae Kim ),최영윤 ( Young Yun Choi ),채종귀 ( Jong Wee Chae ) 대한금속·재료학회 2010 대한금속·재료학회지 Vol.48 No.1
Leaching and solvent extraction experiments have been performed to develop a hydrometallurgical process for the recovery of nickel and cobalt from nickel laterite ore with high magnesium content. Most of the nickel and magnesium in the laterite ore dissolved at leaching conditions of 80℃ and 100 g/L sulfuric acid concentration. while half of the cobalt and iron were leached at the same conditions. Solvent extraction experiments were carried out with D2EHPA and saponifed D2EHPA from a synthetic solution containing Ni, Co, and Mg. The extraction percentage of Co, Mg. and Ni by D2EHPA was very low in a pH range of 4.4 to 7.3. while the extraction percentage sharply increased by using saponified D2EHPA. The stripping percentage of the metals from the saponified D2EHPA increased with sulfuric acid concentration and reached 99.9% at 1 M H2SO4 solution.
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최영윤 慶北大學校 齒科大學 1997 慶北齒大論文集 Vol.14 No.-
국산 치과용 다이아문드 버의 개발을 위해 다이아몬드 버를 실험으로 제작하고, 그 연삭특성을 비교·평가하기 위해 제작한 다이아몬드버와 현재 시판중인 외국산 다이아몬드 버를 대상으로 표면양상관찰, 연삭저항 측정 및 AE측정을 실시하여 다음과 같은 결과를 얻었다. · 버 표면 관찰 결과 제작한 다이아몬드 버의 표면은 100-130㎛ 크기의 다이아몬드 연삭입자가 고르게 분포되고, 결합재 금속층과도 잘 연결된 양상을 나타내었으며, 시판의 다이아몬드 버들과도 큰 차이없이 유사한 표면 양상을 보였다. · 연삭저항 실험시 주추회전수가 증가할수록 제작한 버의 법선분력은 감소하였으나, 접선분력은 큰 변화를 나타내지 않았고, 시판의 버들에서도 동일한 양상을 보였다. · 이송속도가 증가할수록 제작한 다이아몬드 버의 법선분력은 증가하였으며 기타 시판버들의 법선분력도 역시 증가하였으나 제작한 버에서 가장 큰 값을 보였다. 이송속도 증가에 따른 접선분력은 법선분력과 동일한 양상을 보이나 약 10/1정도의 작은값을 보였으며 제작한 버와 시판버 사이에 큰 차이는 없었다. · 소재제거울에 따른 비연삭 에너지 변화는 소재 제거율이 낮은 경우에는 제작한 버는 시판의 버들과 차이없는 비연삭 에너지를 보였으나, 소재 제거율이 커질 경우 제작한 버의 비연삭 에너지는 시판 버들보다 큰 값을 보였다. · 연삭에 따라 발생한 AE 사상수는 수직 연삭저항이 가장 큰 제작한 버에서 가장 작았고, 시판 버의 있어서도 수직 연삭저항이 클수록 AE 사상수가 작은 경향을 보였다. · 연삭실험 후 버 표면은 연삭후기 고진폭 AE가 많이 발생한 제작한 버 및 Horico 제품에서 좀 더 많은 다이아몬드 연삭입자의 탈락파 파절양상을 관찰할 수 있었으나, 이외 시판 버들에서도 역시 동일한 양상이 관찰되었다. 따라서 연삭과정 중 발생한 고진폭 AE는 입자외 파절 및 탈락에 의한 것으로 사료된다.
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최영윤,김교한 大韓齒科器材學會 1993 대한치과재료학회지 Vol.20 No.1
The non-precious dental alloys are widely used in dental fields, but released metal ions in oral cavity can irritate the oral tissue and cause inflammation or allergic reaction. Thus it is very important to estimate the biocompatibility of dental alloys. In this study, the biocompatibility of 5 different nonprecious dental alloys(A-E) was assessed in cytotoxicity test in vitro. We used human periodontal ligament(PDL) cells and human gingival fibroblasts(HGF). The cytotoxicity of alloys was evaluated by the comparison of cell growth and morphologic changes. The composition of alloys was also analysed by ICP spectrometer. The results of these were summerized as follows : 1. The major component of alloy A was titanium, B were cobalt and chromium, C, D were nickel and chromium, and E was copper. A little amount of iron, silicon, aluminium, mangan and berilium were contained in each alloy. 2. On PDL, alloy A showed weak cytotoxicity or was nontoxic, B and D showed weak cytotoxcity C showed moderate toxicity, and E showed extreme toxicity. 3. On HGF cells, the cytotoxicity of alloy A was weak or non toxic, B and D were weak to moderate, C was moderate to marked, and E was marked to strong. 4. The morphology of PDL was similar to that of HGF. Each alloy except E showed normal cellular morphology. However the alloy E showed severe morphological changes such as rounding, shringkage and necrosis. 5. In general, the cytotoxic response of HGF was more sensitive than that of PDL.
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Ion-plating법에 의하여 TiN 피막처리된 교정용 장치물의 변색성 및 내식성
김진희,권오원,최영윤 대한치과교정학회 1993 대한치과교정학회지 Vol.23 No.3
The purpose of this study was to estimate the possibility of practical application of TiN ion-plating method on orthodontic appliances. TiN was coated on the surface of orthodontic stainless steel roll band by means of ion-plating method, and colorimetric properties of its obtained TiN film were investigated by using color analyzer. Also its corrosion and discoloration properties were compared with those of non ion-plated stainless steel roll band by using immersion test, which was done in 1N HCI solution for 10 days. Both weight changes and surface corrosion appearances of specimens for each day were respectively investigated by using electronic weighing machine and SEM(Scanning Electron Microscope). The discoloration degress of TiN-coated specimens immersed in 1N HCI solution were investigated by using color analyzer and then judged by N.B.S.(National Bureau of Standard) Unit. The results of this study were summarized as follows. ㆍTiN ion-plated films showed the hue of 5Y, the value of 7, and the chroma of 3 by Munsell notations. ㆍThe weight losses and surface changes of TiN ion-plated specimens immersed in 1N HCI solution were less than those of non ion-plated specimens. It was shown, therefore, that the corrosion resistance was significantly improved by TiN ion-plating. ㆍThe discoloration degrees of non ion-plated specimens were too significant to be examined by color analyzer, while those of TiN ion-plated specimens were slight when judged by N.B.S. Unit. It was also apparent, therefore, that the anti-doscoloration property was significantly improved by TiN ion-plating.
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