• Food Science and Preservation
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• v.4 no.3
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• pp.287-293
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• 1997

This study was investigated to viscosity, color, chemical properties, and lipid and fatty acid composition for examination of physical and chemical characteristics of sesame oils. Yield of sesame oil was higher in Ansan sesame than that of Chinese and Dambaek sesame. Viscosity of sesame oils was higher than that of shame oils from Dambaek and Chinese sesame, but turbidity and sedimentation rate were higher in Dambaek's sesame oil than those of Ansan's and Chinese sesame oils. In the acid value, saponification value and iodine value of sesame oils, and chemical characteristics of Dambaek's sesame oil were better than those of the others. The neutral, glycolipid and phosholipid contents of sesame oils were 91.1∼92.1, 2.5∼3.5 and 5.5∼6.4%, respectively. The major fatty acids of sesame oils were oleic, linoleic palmitic and stearic acid. The content of oleic acid was higher in Dambaek's and Ansan's sesame oil than that of Chinese sesame oil, and the content of linoleic acid was higher in Chinese sesame oil than the others. The fatty acid composition of neutral lipid, glycolipid and phospholipid were similar to those of total lipid. The ratio of unsaturated fatty acid and saturated fatty acid was higher in Korean sesame oils than those in Chinese sesame oil. The mineral(Mg, Cu, Fe, In, Al, Mn) content of Korean sesame oils was higher than that of Chinese sesame oil. and heavy metals(Cu, Ag, Pb, Cd, As) were not detected.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.11.2-11.2
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• 2011

A key technological issue related to the implementation of dye-sensitized solar cells (DSSCs) is the replacement of Pt at the counter electrodes with an inexpensive and electro-chemically stable alternative. Carbon based nanomaterials could be promising candidates, but in practice they exhibit inadequate device performance. Here, we report very thin graphene oxide (GO)/metal hybrid films as transparent counter electrodes for high-efficiency DSSCs. Transparent GO/Pt and GO/Au hybrid films showed cell efficiencies of 9.2 and 9.0%, respectively (improvements of 9.5 and 7.1% over conventional Pt counter electrodes). More interestingly, highly stable DSSCs with GO hybrid films from relatively inexpensive metals such as Cu and Ni have been demonstrated with efficiency values comparable to Pt counter electrodes. The results reported in this study should enable low-cost fabrication of DSSCs because it allows the use of relatively inexpensive metals such as Au, Cu, Ni, and Ag that could not be previously employed in DSSCs with iodide/tri-iodide electrolyte due to corrosion.

• Ocean and Polar Research
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• v.28 no.2
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• pp.187-199
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• 2006

The Kuroko-type seafloor massive sulfide deposits found in the western Pacific have been considered to have potentials for economic recovery of Au, Ag, Cu, Zn, and Pb. In this study, a preliminary model was developed for the technical and economic evaluation of them. The FRSC site on Lau Basin in the Tonga EEZ was selected as a target. In this study, no construction In for the metallurgical processing subsystem was accounted for. Instead, it was assumed to sell the Cu, Zn, and Pb concentrates to the existing sulfide customer smelter. The low total investment costs for the development make the venture very attractive. However, the result of the economic feasibility evaluation is still less attractive with the mean metal yield of the Kuroko on land. It is considered that commercial mining may be plausible if the richer metal yields are applied to the development. Quantitative information for metal yield is necessary for a more accurate evaluation. However, the important resource potential information regarding the amount of ore body, the inside structure, and the metal yields have not yet been clarified sufficiently. h addition, the flotation of ore body using seawater has not been tested yet. It is necessary to solve these problems through the experimental R&D and a survey.

• Economic and Environmental Geology
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• v.30 no.5
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• pp.407-416
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• 1997

Soil, tailings, stream sediment and surface water samples collected in the vicinity of the Geumwang Au-Ag mine were analyzed in order to investigate the pollution level of heavy metals and to determine the dispersion patterns. Although the maximum concentrations of soils collected at the flotation plant and tailings dam were 9,270 ppm As, 17 ppm Cd, 1,480 ppm Cu, 10,080 ppm Pb and 18,400 ppm Zn, dispersion of heavy metals were limited in the vicinity of the flotation plant and tailings dam. This may be due to high pH values (> 8.0) of the soils by flotation solution for mineral processing. The pH values of water samples near the flotation plant and tailings dam were over 8.0 and Cd, Cu and Zn concentrations were not detected. The waters in the vicinity of Geumwang mine generally belong to a $Ca^{2+}-SO_{4}{^{2-}}$ $(HCO_3{^-})$ type.

• Advances in nano research
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• v.9 no.2
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• pp.113-122
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• 2020

Surface-Enhanced Raman Scattering (SERS) spectroscopy is a multifaceted surface sensitive methodology which exploits spectroscopy-based analysis for various applications. This technique is based on the massive amplification of Raman signals which were feeble previously in order to use them for appropriate identification at qualitative and quantitative in chemical as well as biological systems. This novel powerful technique can be utilized to identify pathogens such as bacteria and viruses. As far as SERS is concerned, one of the most studied problems has been functionalization of SERS active substrate. Metal colloids and nanostructures or microstructures synthesized using noble metals such as Au, Ag and Cu are considered to be SERS active. Silver and gold are extensively used as SERS active substrates due to chemical inertness and stability in air compare to copper. However, use of Cu as a suitable alternative has been taken into account as it is cheap. Herein, we have synthesized air-stable copper microstructures/nanostructures by chemical, electrochemical and microwave-assisted methods. In this paper, we have also discussed the use of as synthesized copper micro/nanostructures as inexpensive yet effective SERS active substrates for the fast identification of micro-organisms like Staphylococcus aureus and Escherichia coli.

• Analytical Science and Technology
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• v.7 no.3
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• pp.293-299
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• 1994

Fifty ancient Korean coins originated in Choson period have been determined for 11 elements such as Sn, Fe, As, Au, Co, Sb, Ir, Os, Ru and Ni by destructive and non-destructive neutron activation analysis as well as for 3 elements such as Cu, Pb and Zn by atomic absorption spectroscopy. The multivariate data have been analyzed by principal component mapping method. The spread of sample points in the eigenvector polt has been attributed to common origins of some elements.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.740-742
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• 1998

In this paper, we described the effect of rapid thermal annealing on the electrical properties of interfacial layer between various top electrodes and $(Ba_{0.5}Sr_{0.5})TiO_3$ thin films. BST thin films were fabricated on Pt/TiN/$SiO_2$/Si substrate by RF magnetron sputtering technique. AI, Ag, and Cu films for the formation of top electrode were deposited on BST thin films by thermal evaporator. Top electrodes/BST/Pt capacitor annealed with rapid thermal annealing at various temperature. In $(Ba_{0.5}Sr_{0.5})TiO_3$ thin films with Cu top electrode annealed at $500^{\circ}C$, the dielectric constant was measured to the value of 366 at 1.2 [kHz] and the leakage current was obtained to the value of $5.85{\times}10^{-7}\;[A/cm^2}$ at the forward bias of 2 [V].

• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.1-9
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• 2011

Understanding the void characterization in the solder joints has become more important because of the application of lead free solder materials and its reliability in electronic packaging technology. According to the JEDEC 217 standard, it describes void types formed in the solder joints, and divides into some categories depending on the void position and formation cause. Based on the previous papers and the standards related to the void, reliability of the BGA solder joints is determined by the size of void, as well as the location of void inside the BGA solder ball. Prior to reflow soldering process, OSP(organic surface preservative) finished Cu electrode was exposed under $85^{\circ}C$/60%RH(relative humidity) for 168 h. Voids induced by the exposure of $85^{\circ}C$/60%RH became larger and bigger with increasing aging times. The void position has more influence on mechanical strength property than the amount of void growth does.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1229-1232
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• 2005

We report the method of preventing the grey color of Bi based glass frits caused by reduction of $Bi_2O_3$. To prevent reduction of $Bi_2O_3$, we controlled the melting temperature. Low melting temperature reduces the reduction of $Bi_2O_3$ and that makes clarity transparent glass cullets. After firing, glass frits that melted at lower temperature showed better transparency. To prevent the browning, we used some additives like CuO, $CeO_2$, CoO and $TiO_2$. The colors of glass cullets were varied according to additives. After firing, dielectric layer contained additives showed better transparency than the one without additives. In the point of reaction between dielectric layer and Ag electrode, CuO was the most effective additive in preventing the yellowing.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.19-24
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• 1999

The multilayer chip band pass filter for mobile communication is fabricated and designed. The size, insertion loss, center frequency and band width of multilayer chip filter are 4.5$\times$4.4$\times$1.8[mm], 3.0[dB] and 700[MHz]$\pm$15[MHz] respectively. The chip filter using $BiNbO_4$with CuO 0.06wt% +$V_2O_5$.lwt% was fabricated by screen printing with Ag electrode after tape casting. Insertion loss and center frequency of the fabricated chip filter are 2.58[dB] and 692.5$\pm$15[MHz] respectively. The center frequency was lower 7.5[MHz] than design result, but other characteristics of chip filter were similar to the ruts ultras of design result.