• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.283.2-283.2
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• 2008

• Asian-Australasian Journal of Animal Sciences
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• 제12권4호
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• pp.579-584
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• 1999

The trace mineral status of cattle in the smallholder grazing areas of Sanyati and Chinamhora in Zimbabwe was evaluated during the rainy and dry seasons of 1994 and 1995. The evaluation was done in terms of mineral concentration in blood plasma. Plasma copper in calves, steers and cows in the dry season was; Sanyati: 0.55, 0.59, and 0.61; Chinamhora: 0.59, 0.58, and $0.60{\mu}g/ml$, respectively versus a normal of $0.65{\mu}g/ml$. In the rainy season, copper was deficient at both sites (averaging $0.56{\mu}g/ml$ and $0.59{\mu}g/ml$ at Sanyati and Chinamhora, respectively). Plasma selenium in the dry season was 0.017, 0.025, and $0.017{\mu}g/ml$ for calves, steers and cows, respectively at Sanyati versus a normal of $0.03{\mu}g/ml$ and therefore considered to be deficient. Iron, zinc and cobalt were found to be generally high and therefore unlikely to be deficient. Copper and selenium are recommended in salt licks in these environments.

• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.367-370
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• 2018

Lysozyme is an antibacterial enzyme that is found in most of body fluids. Lysozyme in tears plays a primary role in protecting eye from harmful environments; if lysozyme is degraded or inhibited, eyes are likely to be more vulnerable to bacterial infection. In this study, lysozyme activity was evaluated according to varying concentrations of heavy metals, copper, zinc, cobalt and manganese and light metal, calcium that are frequently found in airborne particulate matters and was assayed using a dye-quenching lysozyme substrate, Micrococcus lysodeikticus. Less fluorescence intensity was observed with increasing amounts of copper, zinc, manganese and cobalt but not with calcium suggesting that these metals have some affinity with lysozyme and inhibit lysozyme activity. When albumin, the second most common protein in tears, was added on the reaction of lysozyme and metals, lysozyme activity was partially restored. This finding suggests that the albumin might protect damage caused by metals on lysozyme. To identify whether the decrease in enzymatic activity was related to structural changes of lysozyme, SDS-PAGE was conducted and only with copper did lysozyme show marked smearing bands on the SDS-gel, meaning that copper degraded lysozyme consistent with the sharpest activity decrease.

• 대한화학회지
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• 제33권2호
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• pp.208-214
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• 1989

구리(Ⅱ)와 코발트(Ⅱ)의 테트라 티오시안 착이온은 Amberlite LA 1, Alamine 336 또는 Aliquat 336과 같은 고분자량 알킬아민과 이온쌍 화합물이 형성되면 붉은색과 푸른색을 띠어 파장 480nm와 625nm에서 각각 최대 흡수 봉우리를 나타내므로 같은 조건에서 이들 이온쌍 화합물을 methyl isobutyl ketone으로 동시 추출하여 분광광도법으로 두 금속원소를 동시 정량하는 방법을 기술하였다. 그러나 각 흡수스펙트럼이 서로 조금씩 겹치기 때문에 흡광도로부터 농도를 구하기 위하여는 두개의 연립방정식이 필요했다. Fe(Ⅲ)와 Ni(Ⅱ)은 적은 양이 공존하더라도 구리 정량에 영향을 주었다. 이 동시정량법에 의해서 강철과 광물시료의 분석결과는 구리와 코발트 원소를 각각 분석한 결과와 잘 일치하였다.

• 자원리싸이클링
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• 제31권1호
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• pp.21-28
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• 2022

폐리튬이온배터리를 고온에서 용융환원시키면 코발트, 니켈 및 구리 금속합금상을 얻을 수 있다. 이러한 금속합금상으로부터 금속을 분리회수하기 위한 공정을 개발하기 위해 코발트, 니켈 및 구리 금속을 혼합한 금속혼합물을 3% 과산화수소를 함유한 2 M 황산용액으로 침출하면 9.6%의 구리와 함께 코발트와 니켈이 모두 침출된다. 침출용액에서 Cyanex 301로 구리(II)가 선택적으로 추출되었으며, 30% 왕수로 구리(II)를 탈거했다. 구리가 분리된 여액에서 이온성액체인 ALi-SCN으로 Co(II)를 선택적으로 추출했으며, 15%의 암모니아용액으로 3단의 교차식 탈거를 통해 모두 탈거했다. 본 연구를 통해 코발트, 니켈 및 구리 금속혼합물의 황산침출액에서 용매추출로 세 금속을 분리할 수 있는 공정을 제안했다.

• 한국표면공학회지
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• 제57권3호
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• pp.140-154
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• 2024

As the trend towards miniaturization in semiconductor integration process, the limitations of interconnection metals such as copper, tungsten have become apparent, prompting research into the emergence of new materials like cobalt and emphasizing the importance of studying the corresponding process conditions. During the chemical mechanical polishing (CMP) process, corrosion inhibitors are added to the slurry, forming passivation layers on the cobalt surface, thereby playing a crucial role in controlling the dissolution rate of the metal surface, enhancing both removal rate and selectivity. This review investigates the understanding of the cobalt polishing process and examines the characteristics and behavior of corrosion inhibitors, a type of slurry additive, on the cobalt surface. Among the corrosion inhibitors examined, benzotriazole (BTA), 1,2,4-triazole (TAZ), and potassium oleate (PO) all improved surface characteristics through their interaction with cobalt. These findings provide important guidelines for selecting corrosion inhibitors to optimize CMP processes for cobalt-based semiconductor materials. Future research should explore combinations of various corrosion inhibitors and the development of new compounds to further enhance the efficiency of semiconductor processes.

• 에너지공학
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• 제5권1호
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• pp.56-64
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• 1996

본 연구는 방사성 폐액의 처리를 목적으로 화학처리와 한외여과막의 결합공정에 의해서 Cs과 Co이온의 제거 특성을 조사하였다. 실험은 회분식 UF Stirred Cell을 이용하였고, 화학결합제로서 Cs에 대해서는 시안화철구리화합물, 그리고 Co에 대해서는 Polyacrylic Acid(PAA)를 주입하여 Cs이온과 Co이온의 제거 거동을 조사하였다. Cs의 결합특성은 Langmuir Isotherm형태의 식으로 나타내어 평가하였으며, Cs/K$_2$Cu$_3$(Fe(CN)$_{6}$)$_2$의 몰비가 1.5에서 효율적인 조건임을 알 수 있었다. Co의 제거효율은 용액의 pH, PAA및 Co이온의 몰비에 의해서 결정되었다. Co의 제거거동은 리간드와 Co와의 결합,용액의 pH및 Co농도와의 상호작용에 의한 평형관계식에 의해서 평가하였으며, 이때 90%의 제거율을 얻기 위한 조건은 몰비가 2($\beta$=2)이고 pH가 5.6이었다. 이의 결과로부터 Cs과 Co의 동시제거을 위한 화학첨가제의 주입방법에 대한 제거성능을 평가하였다.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1757-1763
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• 2004

A new series of nickel(II), cobalt(II)/(III) and copper(II) complexes of 14, 15 and 16-membered of macrocyclic ligands have been prepared and characterized by elemental analyses, IR, UV-VIS and $^1H-NMR$ spectra, magnetic susceptibilities, conductivities, DTA and ESR measurements. Molar conductances in DMF solution indicate that, the complexes are nonelectrolytes except (9-12) complexes. The electronic spectra show that, all complexes are square planar or distorted octahedral geometry. The ESR spectra of solid complexes (4), (8) and (11) show square planar of axial type symmetry $(d_{x2-y2})$ with considerable covalent bond character. However, complex (12) shows a spectrum of octahedral geometry with $d_{z2}$ ground state. Complex (12) shows exploitation in reducing the amount of electron adducts formed in DNA during irradiation with low radiation products.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2001년도 춘계연구발표회 논문개요집
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• pp.70-71
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• 2001

• Ocean and Polar Research
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• 제31권2호
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• pp.167-176
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• 2009

Cobalt-rich manganese crusts on seamounts have received an increasing amount of attention as future resources for Co, Ni, Cu, and Mn. A dearth of detailed information regarding the relevant distribution characteristics, mining technologies, and ore processing technologies, however, has precluded potential evaluations of the technical and economic advantages of these crusts. In the past 4 years, Korea has undertaken a survey of the cobalt-rich manganese crusts in and around the Magellan Seamount and Mid-Pacific Mountains. This paper introduces the preliminary feasibility study of the distribution features and R&D results centered around the development of the cobalt-rich manganese crusts. The evaluation model was developed by modifying the model for the manganese nodules. In addition to considering the geological and geophysical differences between the manganese nodules and the cobalt-rich manganese crusts, an ore dressing subsystem was installed in the model. The mining subsystem is composed of a self-propelled collector--a pipeline with submersible hydraulic pumps for crust lifting. The smelting and chlorine leach method was selected for metallurgical processing. The production scales were established at 2,500t/y of cobalt metal. The production of three metals--cobalt, nickel, and copper--was considered in terms of metallurgical processing. The economic feasibility analyses demonstrated that the payback period was 11.4 years, the NPV was 36M$, and the IRR was 9.6% with the economic factors in the case of a cobalt price of US$ 25/lb. It was also demonstrated in this study that the payback period was 8.6 years, the NPV was 154M$, and the IRR was 14.0% in the case of a cobalt price of US$ 30/lb. This indicates that the approach under consideration appears to offer greater potential given the predicted metal prices.