• Journal of the Korea Concrete Institute
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• v.21 no.2
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• pp.153-158
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• 2009

Using non-invasive surface measurement method, the corrosion state of steel embedded inside concrete can be measured by placing four electrodes on the surface of concrete. Modeling of such measurements can provide valuable information as how interfacial impedance between corroded steel and surrounding concrete results in measured impedance on the concrete surface. In this paper, the modeling of surface measurement technique is used for the determination of the sensitivity of the measurements with respect to steel bar size embedded inside concrete and cover thickness. Modeling results indicated that steel bar sizes varied from D10 to D35 could be identified. Concrete cover thickness changes from 0.02 m to 0.1 m was also distinguished using the modeling scheme. The results confirm this modeling technique is capable of determining steel bar sizes and cover thickness, as well as simulating corrosion responses.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.61-66
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• 2012

Chemical Mechanical Planarization (CMP) is a polishing process used in the microelectronic fabrication industries to achieve a globally planar wafer surface for the manufacturing of integrated circuits. Pad conditioning plays an important role in the CMP process to maintain a material removal rate (MRR) and its uniformity. For metal CMP process, highly acidic slurry containing strong oxidizer is being used. It would affect the conditioner surface which normally made of metal such as Nickel and its alloy. If conditioner surface is corroded, diamonds on the conditioner surface would be fallen out from the surface. Because of this phenomenon, not only life time of conditioners is decreased, but also more scratches are generated. To protect the conditioners from corrosion, thin organic film deposition on the metal surface is suggested without requiring current conditioner manufacturing process. To prepare the anti-corrosion film on metal conditioner surface, vapor SAM (self-assembled monolayer) and FC (Fluorocarbon) -CVD (SRN-504, Sorona, Korea) films were prepared on both nickel and nickel alloy surfaces. Vapor SAM method was used for SAM deposition using both Dodecanethiol (DT) and Perfluoroctyltrichloro silane (FOTS). FC films were prepared in different thickness of 10 nm, 50 nm and 100 nm on conditioner surfaces. Electrochemical analysis such as potentiodynamic polarization and impedance, and contact angle measurements were carried out to evaluate the coating characteristics. Impedance data was analyzed by an electrical equivalent circuit model. The observed contact angle is higher than 90o after thin film deposition, which confirms that the coatings deposited on the surfaces are densely packed. The results of potentiodynamic polarization and the impedance show that modified surfaces have better performance than bare metal surfaces which could be applied to increase the life time and reliability of conditioner during W CMP.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.6
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• pp.761-769
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• 1999

In this paper the effect of aging heat treatment to the Corrosion behavior for the Nimonic 80A superalloy was studied by AC Impedance methods. Tested solution was 3.5% with tempera-ture $25^{\circ}C$ Electro-chemical corrosion test were carried out for the Nimonic 80A super-alloy which solution heat treated at $1080^{\circ}C$ for 8 hours followed by aging heat treated at $650^{\circ}C,\;700^{\circ}C,\;750^{\circ}C\;800^{\circ}C$ and $850^{\circ}C$ with 16hours under vacuum environment. The obtained results were as follows; 1. Base metal and solution-treated materials were exhibited similar corrosion tendency as Ran-dle equivalent cell. The value of passive film resistance was 579 ohms for the base metal and 124,770 ohms for the solutionized metal such a difference was arose by the ${{\gamma}_^'}$ precipitate on the metal surface during heat treatment. 2. The measure value of $R_p$ for heat-treated at $650^{\circ}C,\;700^{\circ}C,\;800^{\circ}C$and $850^{\circ}C$ were 97,943, 93, 111, 26,961, 15,798 and 11,780ohm respectively. Which indicated that the passive film resistance Rp was reduced as aging temperature increased due to the growth of grain size and sensitization at the grain boundary. 3. The similar tendency was exhibited for corrosion behavior of the electro-chemical corrosion polarization method and AC impedance method and confirmed that AC impedance method was useful tool for corrosion research.

• Structural Engineering and Mechanics
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• v.1 no.1
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• pp.103-118
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• 1993

The near field is discretized into finite elements, and the far field into infinite elements. Closed form far-field solutions to three fundamental problems are used as the shape functions of the infinite elements. Such infinite elements are capable of transmitting all surface and body waves. An efficient scheme to integrate numerically the stiffness and mass matrices of these elements in presented. Results agree closely with those obtained by others.

• 한국초전도학회:학술대회논문집
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• v.13
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• pp.32-32
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• 2003

• 한국초전도학회:학술대회논문집
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• v.13
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• pp.39-39
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• 2003

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.145-146
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• 2014

실리콘을 기반으로 한 양극 재료는 리튬 이온전지에서 높은 용량을 위한 재료에 널리 알려져 있지만, 아직까지 극복해야 할 기술적인 문제들이 많이 있다. 이유는 전기화학 공정 중에 발생하는 큰 부피 변화 때문이다. 본 기술 동향에서는, 리튬 이온전지에 사용될 실리콘 기반 재료의 화합물 시스템, 나노 구조 배열, 재료 합성 방법, 전기화학 성능 측면에서 기술하였다. 본 논문은 실리콘을 기반으로 한 재료의 장단점과 성능과 관련한 기본 메커니즘을 이해하는 데에 좋은 자료가 될 것이다. 따라서 리튬 이온전지 연구자들에게 유익한 자료가 될 것으로 사료된다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.104-104
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• 2008

Ti과 Ti합금은 우수한 생체적합성을 가지고 있어 생체용 재료로 널리 이용되고 있지만 기계적 물성 및 합금원소의 세포 독성에 대한 문제가 제시되고 있다. 본 실험에서는 세포 독성이 없는 Nb과 Zr을 합금원소로 하여 Ti-Nb-Zr 3원계 합금을 제조하고 생체적합성을 향상시키기 위해 양극산화법을 이용하여 $TiO_2$ nanotube를 형성하고 AC임피던스를 통하여 그 특성을 조사하였다.

• Journal of the Korean institute of surface engineering
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• v.26 no.4
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• pp.163-174
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• 1993

The effect of gelatine on the electrodeposition of copper in cupric sulfate-sulfuric acid solution was investi-gated using an ac impedance technique. In the presence of gelatine, the charge transfer resistance was in-creased and the electrical double layer capacitance was decreased. A model was suggested to explain the im-pedance spectra and it fitted well the experimental data. Also the uniformity of deposit thickness was in-creased while the grain size was decreased by the addition of gelatine.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.824-828
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• 2003

This paper explains problems of force-reflecting teleoperation grinding work and proposes some methods to solve those. For stable contact between robot tool(grindstone) and contact surface the mechanical impedance force control is used. The sliding phenomenon of grindstone has been appeared at the contact surface during the grinding work. The sliding problems caused by friction and rotation of grindstone are eliminated by using tangential direction sliding compensation control. The rotation force of grindstone makes the tool move to tangential direction along the surface suddenly even though an operator pushes the tool only in normal direction to the surface. Normal direction force control is applied for grinder not to roll and fracture on the grinding surface. Vibration problem of grindstone is decreased by second order low-pass filter. Therefore we can precise grinding work at the grinding surface and feel the reality