• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.113-113
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• 1993

항바이러스 작용을 기대하여 6-azauridine의 2',3'-seco 유도체와 이들의 cyclic phosphate 유도체를 합성하였다. 6-azauridine으로부터 periodate oxidation에 의해 2',3'위치를 개열, 환원하여 얻은 triol의 3',5'위치를 acetonide 형으로 보호한 후 2'위치를 tosylation, azidation 하고 deprotection하여 2'-azido-2',3'-seco 유도체 (1)를 얻었다. 2',3'-diazido-2',3'-seco 유도체(2)는 6-azauridine의 2',3'-위치를 먼저 보호한후 5'위치를 benzoylation, 2',3'-deprotection, periodate oxidation 개열로 얻은 diol을 tosyl화 azido화 하고 deprotection하여 얻었다. 5'-azido-2',3'-seco 유도체(3)는 화합물 (2)의 합성시와 동일하게 먼저 2',3'-acetonide로 한후 5'-위치를 tosyl화, azido화 하고 deprotection, 2',3'-perodate 산화 개열등으로 얻었다. cyclic phosphate 유도체 (4)는 상기화합물 (2)를 4-NPPDC로 처리하여 3',5'-p-nitrophenylphosphoryltrioxy 유도체 (5)를 얻고 이것으로부터 3',5'-phosphoryltrioxy 유도체의 ammonium salt(4)를 얻었다. 이들 화합물의 DNA 및 RNA virus에 대한 antiviral activity는 현재 수행중이다.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.531-538
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• 2010

The electrochemistry characterization of metal is important in many industrial applications. In this study, we investigated the C-V diagrams related to the electrochemistry characterization of nickel. We determined electrochemical measurement by using cyclic voltammetry with a three electrode system. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650mV and measured to the initial point. The scan rate were 100, 150, 200 and 200mV/s. As a result, the C-V characterization of nickel using ethanolamine and ethylethanolamine inhibitor appeared irreversible process caused by the oxidation current from the cyclic voltammogram. After adding ethanolamine compound additive, adsorption film constituted, and the passive phenomena happened. According to the results by cyclic voltammetry method, it was revealed that the effect of the electrochemistry characterization of nickel depends on ethanolamine structure interaction to adsorption complex.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.920-923
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• 2004

We have investgated on the monolayer LB film of BASH-DMPC mixture on an ITO for the photoisomerization by light irradiation. We measured electrochemical properties by using cyclic voltammetry with a three-electrode system, An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode in $NaClO_4$ solution at a variable concentration and monolayer LB films. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150 and 200 mV/s. As a results, LB films of 8A5H-DMPC appeared reversible process caused by the reduction-oxidation current from the cyclic voltammogram.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3331-3337
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• 2012

Ru-modified Pt nanoparticles of various sizes on platelet carbon nanofiber toward methanol oxidation were investigated in terms of particle size effect. The sizes of Pt nanoparticles, prepared by polyol method, were in the range of 1.5-7.5 nm and Ru was spontaneously deposited by contacting Pt nanoparticles with the Ru precursor solutions of 2 and 5 mM. The Ru-modified Pt nanoparticles were characterized using transmission electron microscopy, X-ray photoelectron spectroscopy and cyclic voltammetry. The methanol oxidation activities of Ru-modified Pt nanoparticles, measured using cyclic voltammetry and chronoamperometry, revealed that when the Pt particle size was less than 4.3 nm, the mass specific activity was fairly constant with an enhancement factor of more than 2 at 0.4 V. However, the surface area specific activity was maximized on Pt nanoparticles of 4.3 nm modified with 5 mM Ru precursor solution. The observations were discussed in terms of the enhancement of poison oxidation by Ru and the population variation of Pt atoms at vertices and edges of Pt nanoparticles due to selective deposition of Ru on the facets of (111) and (100).

• Korean Journal of Materials Research
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• v.15 no.4
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• pp.233-239
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• 2005

In this study, the effects of Pd buffer layer on the oxidation resistance of Pt modified-pack aluminized Inconel 738LC, used for gas turbine, were investigated. Pd was electroplated on Inconel 738LC, and Pt was electroplated on the electroplated Pd surface. Thus, the thickness of electroplated Pt/Pd was $10\;{\mu}m$ and the atomic ratio of Pt : Pd was about 6 : 4. After Pt/Pd electroplating, Inconel 738LC was pack aluminized to form the oxidation resistant layer. To investigate the oxidation resistance of Pt/Pd modified-pack aluminized Inconel 738LC, iso-thermal oxidation and cyclic oxidation were performed. The iso-thermal oxdation and the cyclic oxidation data indicated that the Pt/Pd modified-pack aluminized Inconel 738LC was more oxidation resistant than the Pt modified-pack aluminized Inconel 738LC. It was thought that the difference of thermal expansion coefficient between Inconel 738LC and Pt was lowered by the Pd buffer layer.

• Journal of Ocean Engineering and Technology
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• v.14 no.1
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• pp.60-66
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• 2000

In order to study for corrosion behavior of reinforcing steel with oxidation layer. Experiments were done with various NaCl concentrations and with immersion time in simulated concrete pore solution(SPS) the characteristics of corrosion behavior were measured by polarization resistance method and cyclic potentiodynamic method. reinforcements were coated by epoxy except corrosion without oxidation layer and it also showed two anodic-nose. by the result of potention dynamic test the potential curve shift to low with time and anodic-nose was appeared with 3% NaCl solution after 15 days. By result of cyclic Potentiodynamic test the type of corrosion was different accoding to concentration.

• Journal of the Korean institute of surface engineering
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• v.21 no.2
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• pp.68-75
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• 1988

To know the growth behavior of Conductive polyaniline file, the anodic oxidation of anilien on a platiunm in aqueous sulfuric acid solution has been studied. Cyclic votammetry and currenttime transisents method used to investigate the anodic oxidation of aniline to polyaniline films on a platinum. The oxidation of aniline is shown to occur in several steps dependent on the potential. it the phase growth resembles the deposition of a metal film.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2019-2024
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• 2014

NiCu alloys have been suggested as potential candidates for catalysts in glucose oxidation. In this study, NiCu alloys with different compositions were prepared on a glassy carbon substrate by changing the electrodeposition potential to examine the effect of Ni/Cu ratios in alloys on catalytic activity toward glucose oxidation. Cyclic voltammetry and chronoamperometry showed that NiCu alloys had higher catalytic activity than pure Ni and Cu catalysts. Especially, Ni59Cu41 had superior catalytic activity, which was about twice that of Ni at a given oxidation potential. X-ray analyses showed that the oxidation state of Ni in NiCu alloys was increased with the content of Cu by lattice expansion. Ni components in alloys with higher oxidation state were more effective in the oxidation of glucose.

• Journal of the Korean institute of surface engineering
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• v.26 no.5
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• pp.235-244
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• 1993

The oxidation behavior of a two-phase(Ti3Al+TiAl) intermetallic compound, Ti-33.8wt%Al, has been in-vestigated in air at 800, 900 and $^1000{\circ}C$. Though the isothermal oxidation behavior followed a parabolic law up to 100$0^{\circ}C$ indicating that protective oxide scales were formed, the cyclic oxidation behavior followed a lin-ear law in the entire temperature range tested because flaky or stratified scales were usually spalled from the surface during cooling. During oxidation at 80$0^{\circ}C$, the alloy showed excellent oxidation resistance because continuous protective Al2O3 films were formed on the outermost surface of the alloy. However, above $900^{\circ}C$, the oxidation resistance of the alloy was decreased gradually because relatively non-protective TiO2 scales as well as some of Al2O3 scales were formed on the outer oxide scale. The oxidation mechanism of the alloy at different temperature was proposed.

• Korean Journal of Metals and Materials
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• v.47 no.4
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• pp.235-241
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• 2009

The STS304 stainless steel was oxidized isothermally and cyclically at temperatures between 1050 and $1200^{\circ}C$ for 1 hr in air. During isothermal oxidation, it displayed good oxidation resistance at $1050^{\circ}C$. However, it suffered from breakaway oxidation above $1100^{\circ}C$, being accompanied with internal oxidation. During cyclic oxidation, it also displayed good oxidation resistance at $1050^{\circ}C$, but it suffered from massive weight loss above $1125^{\circ}C$. The oxide scales formed consisted primarily of $Fe_2O_3$, $Fe_3O_4$ with and without $Cr_2O_3$. They were generally non-adherent.