- A Study on Detection Characteristics of Cadmium and Lead for Bi Nanopowder-Labeled Electrode
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Gyeoung-Ja Lee, Hyoun-Jin Kim, Hi-Min Lee, Sang-Hoon Lee, Min-Ku Lee, Chang-Kyu Lee
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J Korean Powder Metall Inst. 2008;15(5):393-398.
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DOI: https://doi.org/10.4150/KPMI.2008.15.5.393
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 Abstract
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- Trace analysis of Cd and Pb at surface modified thick film graphite electrode with Bi nanopowder has been carried out using square-wave anodic stripping voltammetry (SWASV) technique. Bi nanopowder synthesized by gas condensation (GC) method showed the size of 50sim100 nm with BET surface area, A_BET=6.8m2g-l. For a strong adhesion of the Bi nanopowder onto the screen printed carbon paste electrode, nafion solution was added into Bi-containing suspension. From the SWASV, it was found that the Bi nanopowder electrode exhibited a well-defined responses relating to the oxidations of Cd and Pb. The current peak intensity increased with increasing concentration of Cd and Pb. From the linear relationship between Cd/Pb concentrations and peak current, the sensitivity of the Bi nanopowder electrode was quantitatively estimated. The detection limit of the electrode was estimated to be 0.15µg/l and 0.07µg/l for Cd and Pb, respectively, on the basis of the signal-to-noise characteristics (S/N=3) of the response for the 1.0µg/l solution under a 10 min accumulation.
- Characteristics of the Surface Coating Layer of Ti5Si3 Intermetallic Compound Obtained by Shock Compaction and Reaction Synthesis Through Underwater Shock Compression
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Sang-Hoon Lee
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J Korean Powder Metall Inst. 2008;15(2):101-106.
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DOI: https://doi.org/10.4150/KPMI.2008.15.2.101
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Abstract
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- The objective of the present study is to investigate the increase in the functional characteristics of a substrate by the formation of a thin coating layer. Thin coating layers of Ti_5Si_3 have high potential because Ti_5Si_3 exhibits high hardness. Shock induced reaction synthesis is an attractive fabrication technique to synthesize uniform coating layer by controlling the shock wave. Ti and Si powders to form Ti_5Si_3 using shock induced reaction synthesis, were mixed using high-energy ball mill into small scale. The positive effect of this technique is highly functional coating layer on the substrate due to ultra fine substructure, which improves the bonding strength. These materials are in great demand as heat resisting, structural and corrosion resistant materials. Thin Ti_5Si_3 coating layer was successfully recovered and showed high Vickers' hardness (Hv=1183). Characterization studies on microstructure revealed a fairly uniform distribution of powders with good interfacial integrity between the powders and the substrate.
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