• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.300-301
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• 2009

• Journal of the Korean GEO-environmental Society
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• v.3 no.1
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• pp.37-45
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• 2002

EDTA-enhanced electrokinetic removal of copper and zinc from contaminated sandy soil was carried out. In desorption equilibrium tests, the required mass ratio of EDTA to metal was 10:1 to obtain over 90% of desorption from soil. The removal of heavy metals with chelating agent EDTA below pH 3 was limited because of EDTA precipitation. In electrokinetic experiments, the pH control at anode chamber was essential and 38% Cu and 56% Zn were removed under 30 mA for 1.5 days. Heavy metal removal was greatly improved by controlling anode and soil pH with circulation of anolyte with NaOH solution, in which >50% heavy metal was removed for 4 days and >70% for 9 days.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.353.2-353
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• 2002

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.493-499
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• 2008

This study was performed to estimate the water quality parameters on corrosion such as pH, turbidity, Fe released concentration, corrosion rate by using batch reactor for corrosion control of phosphate corrosion inhibitor in carbon steel pipes. The pH, conductivity, alkalinity, and Ca hardness showed a slight change for dosing the phosphate corrosion inhibitor with carbon steel pipe in batch reactor. The turbidity was about ten times lower with 5 mg $P_2O_5/L$ of the corrosion inhibitor than that without. The Fe released concentration and corrosion rate was decreased by about 12.2, 24 times with 5 mg $P_2O_5/L$ of the corrosion inhibitor than that without. In conclusion, the optimum concentration of the phosphate corrosion inhibitor was found to be 5 mg $P_2O_5/L$. The effect of the corrosion inhibitor was significant for the carbon steel plate samples tested in this study. The corrosion inhibitor can be an effective cure for corrosion and red water problem preventing the service pipe from further corrosion.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.696-698
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• 2011

We present a new method for the fabrication of film bulk acoustic wave resonator (FBAR) devices that exploits the thin piezoelectric ZnO films particularly sputter-deposited in a mixture of N2O and Ar gases as the reactive and sputtering gases, respectively. Some thermal annealing treatments were performed on the as-deposited ZnO films and also their effects on the resonance characteristics of the FBAR devices were investigated. It was found that with an optimized process, the resonance characteristics of the fabricated FBAR devices could be further improved.

• Journal of the Semiconductor & Display Technology
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• v.9 no.1
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• pp.35-40
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• 2010

We have investigated the effects of hydrogen injection via in-situ gas addition ($O_2$, $H_2$, or $O_2$ + $H_2$ gas) and plasma post-treatment (Ar or Ar + H plasma) on material properties of ZnO that is considered to be as a channel layer in transparent thin film transistors. The variations in the electrical resistivity, optical transmittance and bandgap energy, and crystal quality of ZnO thin films were characterized in terms of the methods and conditions used in hydrogen injection. The resistivity was significantly decreased by injection of hydrogen; approximately $10^6\;{\Omega}cm$ for as-grown, $1.2\;{\times}\;10^2\;{\Omega}cm$ for in-situ with $O_2/H_2\;=\;2/3$ addition, and $0.1\;{\Omega}cm$ after Ar + H plasma treatment of 90 min. The average transmittance of ZnO films measured at a wavelength of 400-700 nm was gradually increased by increasing the post-treatment time in Ar + H plasma. The optical bandgap energy of ZnO films was almost monotonically increased by decreasing the $O_2/H_2$ ratio in in-situ gas addition or by increasing the post-treatment time in Ar + H plasma, while the post-treatment using Ar plasma hardly affected the bandgap energy. The role of hydrogen in ZnO was discussed by considering the creation and annihilation of oxygen vacancies as well as the formation of shallow donors by hydrogen.