• Corrosion Science and Technology
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• v.5 no.6
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• pp.196-200
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• 2006

For the evaluation of corrosion resistance of Al 6061-T6 alloy, Tafel method and immersion test was performed with Friction Stir Weld(FSW) and Gas Metal Arc Weld(GMAW). The Tafel and immersion test results indicated that GMA weld was severely attacked compared with those of friction stir weld. It may be mainly due to the galvanic corrosion mechanism act on the GMA weld.

• Corrosion Science and Technology
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• v.11 no.4
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• pp.108-111
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• 2012

The effects of volume fraction (15-30%) of SiC particulate reinforcements on the corrosion behavior of SiCp/7091 Al composites in the 3.5% NaCl solution were studied by electrochemical techniques and scanning electron microscopy. The results showed that the amount of SiC particulate reinforcements did not cause much difference in the corrosion behavior of SiCp/7091 Al composites but the corrosion rate was proportional to the amount of SiCp reinforcement. And numerous pits and severe dissolution of the matrix was observed probably due to the discontinuities and galvanic effects between Al matrix and SiC reinforcements.

• Corrosion Science and Technology
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• v.15 no.2
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• pp.54-57
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• 2016

Magnesium alloys have been extensively studied in recent years for potential biodegradable implant applications. A great deal of work has been done on the evaluation of the corrosion behaviour of magnesium alloys under in vitro and in vivo conditions. However, magnesium alloys, in general, contain secondary phase particles distributed in the matrix and/or along the grain boundaries. Owing to their difference in chemistry in comparison with magnesium matrix, these particles may exhibit different corrosion behaviour. It is essential to understand the corrosion behaviour of secondary phase particles in magnesium alloys in physiological conditions for implant applications. This paper critically reviews the biodegradation behaviour of secondary phase particles in magnesium alloys.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.988-993
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• 2004

This paper considers corrosion problems in the bolt connection of weathering steel box girder bridge using the external electric type corrosion resistance method which resisted to local corrosion in coated steel surface with contacted air. The weathering steel was created a rust itself in the passive state. but a coated box girder type was easily dew form could be made galvanic cell that accelerated corrosion. so that it was ruled by protection coat with some paint. Therefore, it needed that can be applied the external electric type corrosion resistance method in coated surface. As a result of the test of polarization amount had measured that the weathering steel was higher currents than the general steel by about $5\~10\%$. Therefore. an external electric type corrosion resistance method can be used to protect local corrosion in the coated bolt connection of weathering steel box girders effectively.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.981-986
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• 2002

ACSR of the catenary wires is corrosion degradation progressed by the effect of atmospheric pollution. ACSR which consists of galvanized steel stranded aluminum. The inside of Steel Reinforced is hot-dipped zinc coating steel wire and it takes charge of tension. If ACSR is exposed in atmosphere, the galvanic corrosion is occurred because it is contacted with aluminum. It is occurred the chemical reaction rapidly so that the local a defect is also occurred. If the catenary wires are exposed in atmosphere of pollution conditions, it may cause to reduce the mechanical strength by corrosion degradation and may cause to damage the wires by micro cracks. Accordingly, this study presents the effects of mechanical properties through the corrosion of ACSR.

• Journal of Power Electronics
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• v.16 no.3
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• pp.861-871
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• 2016

With high penetration of renewable energies, power electronic transformers (PETs) will be one of the most important infrastructures in the future power delivery and management system. In this study, an isolated bidirectional modular multilevel DC/DC converter is proposed for PET applications. A modular multilevel structure is adopted as switching valves to sustain medium voltages to achieve modular design and high reliability. Only one high-frequency transformer is used in the proposed converter, which significantly simplifies the circuit and galvanic insulation design. A dual-phase-shift modulation strategy is proposed to regulate the output power and achieve a simple voltage balancing control. A down-scaled (2 kW/20 kHz) prototype is constructed to demonstrate the proposed converter and verify the control strategy. The experimental results comply with the theoretical analysis well, with the highest power efficiency reaching 97.6%.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.164-167
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• 2005

This paper present ZVS Half-Bridge converter Using IM(Integrated Magnetics). In converter system, magnetic components are important devices used for energy storage, energy transfer, galvanic isolation and filtering. The purposes of IM(Integrated Magnetics) are to reduce the number of magnetic components and voltage/current ripple. This topology is use of three magnetics components thus increasing the cost and size of the system. A prototype featuring 300V input, 15V output, 400kHz switching frequency, and 150W output power.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.203-210
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• 1999

We report on some of the preliminary results of the physiological responses resulting from vehicular speed changes. Healthy human subjects (n=5) were studied for the experiments. We measured the physiological responses of the subjects such as Heart Rate Variability (HRV), Galvanic Skin Response (GSR), and skin temperature for day and night vehicular speed change experiments, respectively. Before and after the tasks, we carried out a self-report for acquiring correlation with experiment results. Mean heart rate variability (HRV) and amplitude of GSR and skin temperature were calculated for 3 minutes duration in each state. The analysis of the physiological measures of ANS activity revealed that vehicle speed change-based affective state evoked arousal response pattern featured by HR acceleration, decrease of skin temperature, and increase of GSR amplitude. The obtained results show that despite some differences observed between each state, overall physiological responses show that the activity of the sympathetic nervous system increases as a result of the increase of speed.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.300-309
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• 2010

The influences of sensitization on localized corrosion resistance of 304 stainless steel, were investigated, using micro-dropletcell techniques. Micro-droplet cell allows one to align the micro-electrode to the desired spot of the working electrode and measure directly local current with the potentiodynamic polarization, linear polarization and a.c. impedance. Micro-electrochemical tests were carried out inside of the grain and on grain boundaries separately. It was found that sensitization decreased the pitting potential, increasing corrosion current density around grain boundaries. Galvanic current density was also measured between grain and grain boundaries.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.270-275
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• 2010

Technical issues of steel industry change along with other industrial progresses. Traditionally, steel protection from corrosion environment was the major issue and galvanic metal coatings were mainly used to extend the lifetime of steel products. Nowadays, requirements for steel have become more diversified. More various surface and material properties are required from different field of applications. Naturally, functional surface coating has become one of the most studied areas in steel industry. For functional surface coating, various process technologies and coating products are investigated. In this article, recent trends of functional coating technologies and products are introduced with brief technical descriptions of representative coating products.