• Journal of Korean Ophthalmic Optics Society
• /
• v.3 no.1
• /
• pp.223-228
• /
• 1998

Glass films of $SiO_2-TiO_2-M_xO_y$ (M = Co, Cr or Cu) have been prepared on soda-lime-silica slide glasses by the chemical solution method using a spin-coating technique. Commercially available tetraethyl orthosilicate, titanium trichloride, and cobalt-, chromium- and copper-nitrates were used as starting materials. No crystalline segregations of $Co_3O_4$, $Cr_2O_3$ and CuO were observed by X-ray diffraction ${\theta}-2{\theta}$ scans. From the optical transmission analysis, cobalt existed as $ Co^{2+}$ in tetrahedral coordination, chromium as $Cr^{6+}$ in tetrahedral symmetry and copper as $Cu^{2+}$ in octahedral coordination. Films with a crack-free and no texture exhibited homogeneous interfaces between the films and the substrates along the cross-section.

• Resources Recycling
• /
• v.21 no.1
• /
• pp.49-59
• /
• 2012

One of the world's top resource-rich countries, the Democratic Republic of the Congo has ample reserves of cobalt, iron ore, copper and diamond in particular. Importing most of major mineral resources, the Republic of Korea has examined-together with the Congo government since 2008-the possibility of a project where it supports port construction in the Democratic Republic of the Congo and acquires useful minerals such as zinc, cobalt and copper in exchange through slag reprocessing in the local city of Lubumbashi. This study conducted feasibility analysis on the slag reprocessing project in Lubumbashi, Congo and found that the project's payback period stands at 6.7 years, net present value(NPV) at 34 million dollars and internal rate of return(IRR) at 17.4%. According to sensitivity analysis that takes into account uncertainties concerning taxation, fixed cost, operational cost and resource prices, the NPV of the project ranges from -24.8 million dollars to 92.7 million dollars.

• Journal of Welding and Joining
• /
• v.17 no.2
• /
• pp.104-111
• /
• 1999

The interfacial microstructure and bond strength were examined for WC-Co/Cu/SM45C steel join using a nickel-plated copper in vacuum at 1323K for 0.6ks∼3.6ks. After bonding, microstructure in bonding interface was observed by OM(Optical Microscopy), SEM(Scanning Electron Microscopy) and EPMA(Eelectron Probe Micro Analyzer). The oil cooling was carried out at 353K, the cooling rate in air and furnace was 22K/s and 4.4K/s. respectively. It was found that dendritic widths increased with the content of cobalt and bonding times at 1323K. As a whole, bond strength values at the same bonding condition decreased in this order: WC-13wt.%Co/SM45Csteel. WC-8wt.%Co/SM45Csteel and WC-4wt.%Co/SM45Csteel. The bond strength of WC-13wt.%Co/S45C steel joint in oil cooling was 273MPa. This value was greatly higher than those of 125MPa in furnace cooling and 93MPa in air cooling at 1323K for 0.6ks. The bond strength values were found to be closely associated with the content of cobalt in WC-Co and cooling rate.

• Journal of Soil and Groundwater Environment
• /
• v.9 no.4
• /
• pp.15-23
• /
• 2004

Deicer operations provide traffic safety during winter driving conditions in urban areas. Using large quantities of de-icing chemicals (i.e., $CaCl_2$ and NaCl) can cause serious environmental problems and may change behaviors of heavy metals in roadside sediments, resulting in an increase in mobilization of heavy metals due to complexation of heavy metals with chloride ions. To examine effect of de-icing salt concentration on the leaching behaviors and mobility of heavy metals (cadmium, zinc, copper, lead, arsenic, nickel, chromium, cobalt, manganese, and iron), leaching experiments were conducted on roadside sediments collected from Seoul city using de-icing salt solutions having various concentrations (0.01-5.0M). Results indicate that zinc, copper, and manganese in roadside sediments were easily mobilized, whereas chromium and cobalt remain strongly fixed. The zinc, copper and manganese concentrations measured in the leaching experiments were relatively high. De-icing salts can cause a decrease in partitioning between adsorbed (or precipitated) and dissolved metals, resulting in an increase in concentrations of dissolved metals in salt laden snowmelt. As a result, run-off water quality can be degraded. The de-icing salt applied on the road surface also lead to infiltration and contamination of heavy metal to groundwater.

• Journal of Society of Preventive Korean Medicine
• /
• v.4 no.2
• /
• pp.25-56
• /
• 2000

Trace element are involved in enzymatic activities, immunological reactions. physiological mechanisms. Deficiency in some trace elements, such as iron and iodine. is still an important health problem, The role of trace elements deficiency is suspected in various clinical situations and is now confirmed by well designed supplementation studies. However, the importance of trace elements as chinese herbal constituents is not sufficiently appreciated by the oriental medical profession, although in recent years a significant increase of new finding on their essential character in chinese herbal medicine occurred. It is well known that herbal medicine contains a variety of trace elements which would show therapeutic effects with active components in herbal medicine . In china, recent work showed some positive correlation between trace element and traditional chinese medicine (TCM) in terms of therapeutic effects even if their role in therapeutic effects is still obscure. In korea, not much attention has been on the therapeutic importance of trace element contained in herbal medicine Here, the therapeutic effects of trace element in TCM were reviewed and summarized. 1. Iron, copper, zinc and manganese are mainly contained in TCM. In addtion, chromium, magnesium, molybdenum, nickel, alminium, cobalt, arsenic and selenium has been studied for their therapeutic effects 2. Zinc, is decreased in patients who have deficiency of kindney(腎虛) and chronic disease. Fe is decreased in patients who have deficiency of blood(血虛). However copper is increased in patients who have chronic disease and hepatic disease.3 Iron concentration is high in herbs used for tonifying and nourishing yin or blood(補陰補血藥) Zinc concentration is high also in herb used for tonifying kidiney and vital essence(補腎補精藥). In addition. copper concentration Is high in herb used for replenishing qi(補氣藥) 4 In herbal drugs, the therapeutic substances in TCM are not only organic but also inorganic. It seems that trace elements would be one of components in herb for its therapeutic effects. This indicates that therapeutic effects of TCM should be extended not only to herb itself, bur also to trace elements contained in herb.

• Genomics & Informatics
• /
• v.15 no.4
• /
• pp.162-169
• /
• 2017

Metal binding proteins or metallo-proteins are important for the stability of the protein and also serve as co-factors in various functions like controlling metabolism, regulating signal transport, and metal homeostasis. In structural genomics, prediction of metal binding proteins help in the selection of suitable growth medium for overexpression's studies and also help in obtaining the functional protein. Computational prediction using machine learning approach has been widely used in various fields of bioinformatics based on the fact all the information contains in amino acid sequence. In this study, random forest machine learning prediction systems were deployed with simplified amino acid for prediction of individual major metal ion binding sites like copper, calcium, cobalt, iron, magnesium, manganese, nickel, and zinc.

• Ocean and Polar Research
• /
• v.36 no.4
• /
• pp.505-514
• /
• 2014

The development of deep seabed manganese nodules has been carried out with the aim of commercial development in 2023. It is important to forecast the price of the four metals (copper, nickel, cobalt, and manganese) extracted from manganese nodules because price change is a criterion for investment decision. The main purpose of the study is to forecast the price of four metals using the ARIMA model and VAR model, and calculate the MAPE to compare a goodness-of-fit between the two models. The estimated results of the two models reveal statistical significance and are in keeping with economic theory. The results of MAPE for goodness-of-fit show that the VAR model is between 0.1 and 0.2, and the ARIMA model is between 0.4 and 0.6. That is, the VAR model is better than the ARIMA model in forecasting changes in the price of metals.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.966-969
• /
• 2003

Thin film capacitors with Al-Polymer-Al sandwich structure were fabricated. The bottom and top aluminium (Al) electrodes were deposited by vacuum evaporation and copper phthalocyanine (CuPc), polyaniline-emeraldine base (Pani-EB) and cobalt phthalocyanine/polyaniline - emeraldine base (CoPc /Pani-EB) blend films (which can be used as buffer hole injection layer in OLEDs) were deposited by spin coating technique. X-ray diffractograms indicated amorphous nature of the polymer films whose thicknesses were measured by capacitance and Rutherford Backscattering Spectrometry (RBS) methods. AC conduction studies revealed that the conduction mechanism responsible in these films is variable range hopping of polarons. From D.C conduction studies, it is observed that, the nature of conduction is ohmic in the lower fields and at higher fields the dominating D.C conduction is of Poole-Frenkel type.

• Korean journal of food and cookery science
• /
• v.9 no.3
• /
• pp.195-197
• /
• 1993

This study investigated the contamination of trace metals on edible visceras : tongue, intestine, lung, testis, gira, blood, liver, stomach, and kidney. The edible visceras were selected at random from ten markets in Seoul. The edible visceras underwent freeze drying prior to analysis. The contents of arsenic, cadmium, cobalt, chromium, copper, magnases, molybdenum, lead, and zinc were detected by ICP(Inductively Coupled Plasma Spectrophotometry). The results showed that the levels of trace metals in all the samples fall within the tolerance limit and cadmium in lung tended to be high(>0.1 ppm). Therefore, we may study and investigate continuously on the food contamination of heavy metals for the public health.

• Proceedings of the KIEE Conference
• /
• 1999.11b
• /
• pp.40-42
• /
• 1999

In this paper, light-weight system of linear induction motor(LIM) for light railway train is presented, and is compared with former type of LIM. For the light-weight system without modification of motor size the material of primary core(silicon steel) is changed with iron-cobalt alloy and the material of primary winding(copper) is changed with aluminium. The characteristics of LIM are analyzed. Specially, the air gap magnetic flux density distribution due to end effect is showed with motor velocity, we will present papers continuously through designing and testing a trial product.