• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.425-429
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• 2009

The protection for copper tarnish was developed by surface treatment method and volatile corrosion inhibiting (VCI) technology. The performance of surface treatment and VCI material is also examined in simulated test environment. Benzotriazole (BTAH) solution that contained molybdate showed best performance than others. Usage of VCI materials with surface treatment was more effective. The protection film foamed on the surface of copper was investigated by auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). Molybdate does not participate in the formation of the protective film but promotes the passivation effect. This facilitates the stabilization of the cuprous oxide film, and strengthens the adsorption of BTAH.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1104-1105
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• 2015

Recently, electric power demand increase due to the rapid industrial development. As a result, a power system has been expanded and fault currents are raised. Fault current is detriment effect on protective equipment. Superconducting fault current limiter(SFCL) is one of the solution to solve the fault current reduction. This paper analyzed operating characteristics according to applied location of SFCL in a transmission power system through the PSCAD/EMTDC simulation.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.35-35
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• 2003

Korea has different agricultural pattern from western countries and in particular, pesticide application has been performed by individual farmer. Such situations can result in pesticide exposure to worker at significant level. Thiophanate-methyl is a benzimidazole fungicide, which has been used for the wide range of fungal pathogens in field crops and fruits in Korea. It is insoluble In water, and is stable in neutral, aqueous solution at room temperature. It is a carbendazim precursor and systemic fungicide with protective and curative action. Toxicity to mammalian is low as ADI value is 0.08mg/kg b.w. (Tomlin 2000).

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.143-146
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• 1987

Fiber optics provide a solution to the problems at interference, capacity and reliability in communication. Approximately 20 kilometera of a six-fiber, multimode, longwave($1.3{\mu}m$), graded index silica glass fiber optic cable was helically wrapped around a phase conductor at a Korea Electric Power Corporation(KEPCO) 154KV transmission line. This paper presents an economic comparison of several fiber optic cable installation alternative and discusses the characteristics at the helically wrapped fiber cable, as well as the entire installation, including high voltage phase-to-ground (PTG) end termination, and splicing. The fiber link was installed for the field trial and practical use with overhead composite optical fiber cable which installation performed a few years earlier some other location and is intended to accommodate not only telephone but also supervisory Control and Data Acquisition(SCADA), protective relaying, and telemetry functions.

• Corrosion Science and Technology
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• v.8 no.6
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• pp.227-231
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• 2009

Mg and Mg alloys have been used for lots of applications, including automobile industry, aerospace, mobile phone and computer parts owing to low density. However, Mg and Mg alloys have a restricted application because of poor corrosion properties. Thus, improved surface treatments are required to produce protective films that protect the substrate from corrosive environments. Environmental friendly Plasma Electrolytic Oxidation (PEO) has been widely investigated on magnesium alloys. PEO process combines electrochemical oxidation with plasma treatment in the aqueous solution. In this study, AZ91 Mg alloys were treated by PEO process in controlling the current with PC condition and treated time, concentration of NaF, NaOH, and $Na_2SiO_3$. The surface morphology and phase composition were analyzed using SEM, EDS and XRD. The potentiodynamic polarization tests were carried out for the analysis of corrosion properties of specimen. Additionally, salt spray tests were carried out to examine and compare the corrosion properties of the PEO treated Mg alloys.

• Structural Engineering and Mechanics
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• v.19 no.6
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• pp.603-618
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• 2005

The split Hopkinson pressure bar (SHPB) technique is widely used to characterize the dynamic mechanical response of engineering materials at high strain rates. In this paper, attendant problems associated with testing 70 mm diameter concrete specimens are considered, analysed and resolved. An adaptation of a conventional solid circular striker bar, as a means of achieving reliable and repeatable SHPB tests, is then proposed. In the analysis, a pseudo one-dimensional model is used to analyse wave propagation in a non-uniform striker bar. The stress history of the incident wave is then obtained by using the finite difference method. Comparison was made between incident waves determined from the simplified model, finite element solution and experimental data. The results show that the simplified method is adequate for designing striker bar shapes to overcome difficulties commonly encountered in SHPB tests. Using two specifically designed striker bars, tests were conducted on 70 mm diameter steel fibre reinforced concrete specimens. The results are presented in the paper.

• Korean Journal of Metals and Materials
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• v.49 no.10
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• pp.780-789
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• 2011

The effects of alloyed carbon on the pitting corrosion, the general corrosion, and the passivity behavior of Fe18Cr10Mn0.4NxC (x=0~0.38 wt%) alloys were investigated by various electrochemical methods and XPS analysis. The alloyed carbon increased the general corrosion resistance of the FeCrMnN matrix. Carbon enhanced the corrosion potential, reduced the metal dissolution rate, and accelerated the hydrogen evolution reaction rate in various acidic solutions. In addition, carbon promoted the pitting corrosion resistance of the matrix in a chloride solution. The alloyed carbon in the matrix increased the chromium content in the passive film, and thus the passive film became more protective.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.121-122
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• 2023

This study investigates the anti-corrosion properties of two eco-friendly pyridinium ionic liquids; 4DMN and 4DMP, in a 3.5% NaCl solution. Utilizing weight loss tests, EIS, PDP, quantum chemical calculations, and molecular dynamics simulations, the study demonstrates concentration-dependent inhibition efficiencies of 94% and 92% for 4DMN and 4DMP, respectively. The compounds modulate both anodic and cathodic reactions without altering the corrosion mechanism. EIS data suggest that a protective layer forms, supported by FE-SEM and AFM surface analyses, which reveal improved morphology and reduced roughness. Computational validations corroborate these empirical findings, highlighting the feasibility of these ionic liquids for effective, sustainable corrosion mitigation.

• Journal of Society of Preventive Korean Medicine
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• v.19 no.1
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• pp.109-116
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• 2015

Objective : Solar ultraviolet (UV) light can cause photoaging of human skin. Many researchers have focused on effective prevention to mitigate the aging process. This study was aimed to investigate anti-wrinkle effects of pomegranate concentration solution (PCS) using photoaged hairless mouse model. Method : To clarify the protective effect of PCS against UVB-induced photo-damage, water capacity was measured with transepidermal water loss (TEWL) in SKH-1 hairless mice. In addition, image of skin replicas was analyzed. Results : Our results showed that the PCS treatment protects skin against UVB-induced photoaging, based on the parameters including moisture capacity and TEWL. According to visual assessment of skin replica, application of 1 ml/kg PCS inhibited UV-induced wrinkle formation in mice skin as compared to the vehicle-applied control mice. Conclusion : Taken together, these results indicated that PCS could improve skin wrinkle formation induced by UVB irradiation in SHK-1 hairless mice. PCS could be applied as an anti-wrinkle agent.

• Food Science and Preservation
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• v.9 no.3
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• pp.327-331
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• 2002

To develop the use of natural pigment for food, anthocyanins were isolated from grape peels which were wasted much in korea, and their characteristics were as fellows. pH has a marked influences on the color of the grape peels anthocyanin solution(GPAS). At low pH the color of GPAS was more stable than high pH. With increasing pH the color gradually fades as colorless pseudobases are formed. It showed characteristic bathnochromic shift as the solution increased. Among the sugars tested, glucose showed the most protective effect on the color of GPAS to raise the color stability, while fructose showed an adverse effect. Orgarnic acid such as citric acid prevented the degradation of anthocyanin, but ascorbic acid lowered stability of color considerably. The effect of light on GPAS was found to be very deleterious. The pigment degradation can be minimized by shielding the light from the pigment solution.