• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.11 no.2
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• pp.61-67
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• 2015

3D FEM modeling based on 3D CAD data has been performed to evaluate the efficiency of CP system in a real operating nuclear power plant. The results of it successfully produced sophisticated profiles of electrolytic potential and current distributions in the soil of an interested area. This technology is expected to be a breakthrough for detection technology of damages on buried pipes when it comes into combining with a brand of area potential earth current (APEC) and ground penetrated radar (GPR) technologies. 2D current distribution and 2D current vectors on the earth surface from the APEC survey will be used as boundary conditions with exact 3D geometry data resulting in visualization of locations and extents of corrosion damages on the buried pipes in nuclear power plants.

• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.72-76
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• 2005

Some mononuclear oxovanadium(IV) complexes having the general formula [VOL(bidentate)] (1-4) of which L is tridentate ONS-donor salicylaldehyde S-methyldithiocarbazate (sal-mdtc$^{2-}$) or salicylaldehyde 4- phenylthiosemicarbazate (sal-phtsc$^{2-}$) and bidentate stands for 2,2'-bipyridyl (bpy) or 1,10-phenanthroline (phen) have been synthesized. The complexes were characterized by elemental analyses, FAB mass, UV, IR spectroscopy, and cyclic voltammetry. Two of the complexes [VO(sal-mdtc)(bpy)] (1) and [VO(sal-mdtc) (phen)] (2) were crystallographically characterized. The structures revealed that vanadium atom is octahedrally coordinated by the O, N, and S donor atoms of the tridentate ligand, the two N atoms of bidentate ligand, and the oxo atom. The oxygen donor, occupying an apical position has a trans-labilizing effect, resulting in elongation of the V-N bond. The cyclic voltammograms of the complexes exhibited one cathodic response in the range −d1.45 $\sim$ −f1.52 V due to the reduction of V(IV) to V(III).

• Journal of Electrochemical Science and Technology
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• v.7 no.2
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• pp.153-160
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• 2016

The inhibition ability of N,N-bis(2,4-dihydroxyhydroxybenzaldehyde)-1,3-Propandiimine (DHBP) as a schiff base against the corrosion of API-5L-X65 steel in 1 M HCl solution was evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy. Electrochemical impedance studies indicated that DHBP inhibited corrosion by blocking the active corrosion sites. The inhibition efficiency increased with increasing inhibitor concentrations. EIS data was analysed to equivalent circuit model and showed that the charge transfer resistance of steel increased with increasing inhibitor concentration whilst the double layer capacitance decreased. The adsorption of this compound obeyed the Langmuir adsorption isotherm. Gibbs free energy of adsorption was calculated and indicated that adsorption occurred through physical and spontaneous process. The corrosion inhibition mechanism was studied by potential of zero charge. Polarization studies indicated that DHBP retards both the cathodic and anodic reactions through adsorption on steel surface. Scanning electron microscopy was used to study the steel surface with and without inhibitor.

• Analytical Science and Technology
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• v.8 no.1
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• pp.25-32
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• 1995

Determination method of trace thioglycolate has been studied by adsorptive stripping voltammetry. Copper(II)-thioglycolate complex is adsorbed at the hanging mercury drop electrode and stripped during cathodic scan. Electrolyte was used pH 6.5 phosphate and pH 9.5 borate buffer solutions. Optimal conditions were a copper(II) concentration $1{\times}10^{-4}M$, an adsorption accumulation potential -0.2V, an adsorption accumulation time 60 sec and a scan rate 20mV/sec. A detection limit of $1{\times}10^{-9}M$ thioglycolate was obtained. The method was applied to the determination of thioglycolate in cold wave fluids and depilating creams.

• Journal of Sensor Science and Technology
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• v.9 no.6
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• pp.455-460
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• 2000

Zinc oxide(ZnO) thin films were cathodically deposited on ITO glass from an aqueous zinc nitrate electrolyte. Three main fabrication parameters were taken into account : deposition potential, solution concentration and growth temperature. Different layers of ZnO thin films grown by varying the three parameters were studied by X-ray diffraction, scanning electron microscope and optical absorption spectroscopy. The prepared ZnO thin films were shown as a hexagonal wurtzite structure on the X-ray diffraction patterns and the good quality of ZnO thin films were obtained by potentiostatic cathodic deposition at -0.7V vs. Ag/AgCl reference electrode onto ITO glass from aqueous 0.1 mol/liter zinc nitrate electrolyte at $60^{\circ}C$.

• Journal of the Korean Society for Heat Treatment
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• v.20 no.2
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• pp.78-83
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• 2007

CrN coatings were deposited by cathodic arc ion plating method on the SKD11 steel substrates. Atmosphere temperature of $350^{\circ}C$, arc current of 90 A, nitrogen partial pressure of 1.0-5.3 Pa, and negative bias voltage of 30-135 V were selected. The characteristics of microstructure were investigated with XRD. Hardness, adhesion and friction coefficient measured by microhardness tester, scratch tester, and ball on disk tribometer. Microstructures depended on nitrogen partial pressure and bias voltage. The preferred orientation of the films was changed from (200) to (111) with decreasing pressure and increasing bias voltage. Adhesion properties related with microstructure, but microstructure changes slightly influenced on hardness and friction properties. The critical load.($Lc_1$) and hardness of CrN films deposited at 5.3 Pa, -30 V condition were 55 N(HF1), $2157{\pm}47\;Hk_{0.025}$. The friction coefficient were about 0.5 under dry condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.151-151
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• 2012

빗각 증착법(oblique angle deposition; OAD)을 이용하여 코팅된 알루미늄과 질화 티타늄 박막의 특성을 분석하였다. OAD는 기판과 증발원이 수평하게 위치하는 일반적인 코팅방법과 다르게 기판이 증발원과 수평하게 놓이지 않고 일정한 각으로 기울여 코팅하는 방법을 의미한다. 코팅 시 기판이 증발원과 수평하지 않으면 입사되는 증기가 일정한 각도를 유지하기 때문에 코팅되는 박막의 구조가 달라지고 이로 인해서 물리적 특성도 변하게 된다. 본 연구에서는 음극아크와 스퍼터링을 이용하여 각각 질화 티타늄과 알루미늄을 빗각으로 코팅하여 박막의 미세구조와 물성 변화를 관찰하였다. 스퍼터링을 이용하여 빗각 코팅된 알루미늄의 경우, 박막의 구조가 치밀해지고 표면 조도가 낮아지는 현상이 관찰되었다. 알루미늄 박막의 치밀도와 표면조도 향상은 가시광선 영역의 반사율을 높이는 효과가 있었다. 강판에 알루미늄을 코팅하여 염수분무를 실시한 결과, 치밀한 조직으로 인해서 내식성이 향상되는 결과를 보였다. 음극 아크를 이용하여 빗각 코팅된 질화 티타늄 박막에서 기판과 수직하지 않고 일정한 각도로 기울어진 주상 조직이 관찰되었다. 기판에 수직하게 성장된 질화 티타늄 박막과 비교하여 기울어진 주상 구조의 박막은 경도가 높아지는 특성 변화가 관찰되었다. 빗각 증착법을 이용하여 박막의 조직, 물성 등을 제어할 수 있었다. 박막에 다양한 기능을 부여하는 코팅방법으로 빗각 증착법이 활용될 수 있을 것으로 판단된다.

• Analytical Science and Technology
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• v.15 no.3
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• pp.214-220
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• 2002

The interfacial accumulation of the chromium-cupferron complex and the catalytic wave of its redox process is characterized by cyclic voltammetry. One cathodic peak is observed in the forward scan at -1.45 V. Scanning in the reverse direction produces a inverted peak at -1.39 V, which is indicative of a catalytic process. The optimal conditions of inverted peak were found to be 1 mM borate buffer solution(pH 9.48) containing $1{\times}10^{-4}M$ cupferron, holding potential of -1.8 V and scan rate of 20 mV/s. Using main peak, a preconcentration time of 1 min results in a detection limit of $3.2{\times}10^{-10}M$.

• Analytical Science and Technology
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• v.11 no.3
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• pp.151-155
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• 1998

Electrochemical behaviours on 1.0 mM methylviologen ($MV^{2+}$) in 100 mM NaCl+27 mM $MgCl_2$ solution, without and with sodium dodecyl sulfate (SDS), were studied. The intersection of two lines on ${\Delta}E_p$ (the difference between the anodic, $E_{pa}$, and the cathodic, $E_{pc}$, peak potentials) of the first and second redox waves vs. -log[SDS] plot was determined as a critical micelle concentration (CMC). When $Mg^{2+}$ was added, the effective access of $MV{\cdot}^+$ to the glassy carbon electrode surface became possible and the formation of micelles was retarded.

• Analytical Science and Technology
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• v.8 no.4
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• pp.723-730
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• 1995

Cyclic voltammetry and in situ STM were employed to examine the interfacial structures of a Pt(111) electrode in 0.1 mM KCN (pH9.5) and 0.1 mM KSCN (pH7) solutions. In situ STM atomic resolution revealed well ordered (2${\surd}$3${\times}$2${\surd}$3)$R30^{\circ}$-6CN and ($2{\times}2$)-2SCN structures within the double layer charging region. Six CN adsorbates formed a hollow hexagon, which embraced a coadsorbed $K^+$ cation. In contrast, the coadsorbed $K^+$ cations on the SCN covered Pt(111) were poorly ordered, despite adsorbed SCN formed a long range ordered ($2{\times}2$)-2SCN adlattice. In situ STM revealed the pronounced influence of potential in controlling the structures of compact layers at the proximity of a Pt electrode. Cathodic polarization facilitated the replacement of the coadsorbed cations by protons.