• Journal of Power System Engineering
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• v.19 no.5
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• pp.73-79
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• 2015

The effects of hydrogen charging on the mechanical properties of 304 stainless steels were investigated in conjunction with the detailed examinations of their fracture modes. The dependence of the absorbed impact energy and the surface hardness of the 304 stainless steels on the hydrogen charging time was characterized. The tensile properties of the 304 stainless steels by the variation of cross-head speed were also evaluated at the room temperature. The hydrogen charging was performed by an electrolysis method for all specimens of the 304 stainless steels. The mechanical properties of the 304 stainless steels exhibited the sensitivity of embrittlement due to a hydrogen charging. The correlation between mechanical properties and fracture surfaces was discussed.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.3
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• pp.19-26
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• 1986

The degree of air pollution is usually presented in terms of concentration. But, in evaluating the environmental impacts or air pollution control policies, the concentration values need to be interpreted in terms of damage effects on property and human health. The damage effect varies with the types of pollution, subjects and land use pattern of an affected area. Therefore, this study is aimed at developing a method of analyzing effects of various types of air pollutions on surrounding environmental setting with the EIMS (Environmental Information Management System) developed for land suitability analysis. Using the method formulated in this study, the long- term effects of such pollutants as $SO_2$ and HF on types of vegetation and residents, and potential, short-term effects of HCl leak accidents from manufacturing facilities in Ulsan and Onsan Industrial complex are analyzed. The presentation of the damage effects of air pollution rather than the concentration of pollutants will be useful for the preparation of environmental impact statements, the formulation of environmental policies, and the development of land use plans in heavily industrialized areas.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.295-298
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• 1997

Recycl ing of PP/EPR based bumper coated with polyester urethane paint has been per formed by chemical decoating method. Electronic Speckle Pattern Interferometry (ESP11 has been applied to characterize the deformation of polyolef in based bumper. In additon, physical properties and processability of recycled materials have been investigated by dynamic mechanical thermal analysis, impact test and melt flower index measurement. The results show that the deformation ratio of recycled material is higher than that of virgin one. The morphological change of EPR, degree of distribution and dispersion during the recycling process seem to be the most important factor for the deformation and the mechanical properties of recycled materials. The experimental results obtained show that ESPI is very powerful technique to study the thermal mechanical property of polyolefin bumper system.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.517-522
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• 2001

The purpose of this study is to investigate the thermal embrittlement and the mechanical properties of 2.25Cr-1Mo steel aged at high temperature and stress for 250 hours. Original, aged artificially material were tested to obtain the hardness and impact absorbed energy. Hardness and impact absorbed energy decreased with the increasing aging time. The carbide morphology with the thermal embrittlement was found to contribute to the mechanical property change by X-Ray diffraction method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1771-1778
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• 2000

The purpose of this study is to investigate the thermal embrittlement and the mechanical properties of 2.25Cr-1Mo steel aged at high temperature for the extended periods. Original, aged artificiall y and used material were tested to obtain the tensile strength, hardness and impact absorbed energy. Tensile strength, hardness and impact absorbed energy decreased with the increasing aging time. The carbide morphology with the thermal embrittlement was found to contribute to the mechanical property change by X-Ray diffraction method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.138-146
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• 2012

This research is to analyze the wave propagation characteristics of anisotropic materials subjected to the low-velocity impact. For this purpose, a higher-order finite element program is used to simulate the dynamic behaviors according to the changes of material property, stacking sequence and dimension etc.. Materials for simulation are composed of $[0^{\circ}]_{10s}$, $[45^{\circ}/-45^{\circ}]_{5s}$ and $[90^{\circ}]_{10s}$ stacking sequences. Finally, the results of this simulation are compared with those of wave propagation theory and then the impact responses and wave propagation phenomena are investigated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.214-215
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• 2017

Extreme loads such as impact and explosion have higher strain rate than static loading condition. Therefore, it is necessary to evaluate mechanical properties at high strain rate in order to apply fiber reinforced cement composites to ensure safety performance against impact and explosion. In this study, the compressive properties of fiber reinforced cement composites by strain rate were evaluated.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.138-140
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• 2007

This study aimed to evaluate the low temperature properties of the 18Cr ferritic stainless steel weld. Applied welding methods were LB(Laser Beam) and GTA(Gas Tungsten Arc) welding to compare the different low temperature properties of the welds. Low temperature properties were evaluated by the Charpy impact, Erichsen and Expansion test at low temperature. LB weld showed superior low temperature properties in the cases of the Charpy impact test and expansion test at low temperature, while GTA weld showed a superior low temperature property in the case of Erichsen test at low temperature. The different low temperature properties with test methods are still under analysis and may be due to different crack path depending on the microstructure, test speed and stress concentration during test.

• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.419-424
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• 2003

The physical properties of food playa significant role in the modeling and computation of the heat and mass transfers in basic food processing operations. With the advent of improved analytical techniques, statistical experiment design applications, computing ability and knowledge of the food physical properties of food, there have been significant advances in our ability to predict the impact of processing on the physical properties of food. This article briefly reviews our current ability to predict the influence of processing on the physical properties of food, such as water activity, moisture, color, and rheological characteristics.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.335-338
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• 2005

This study was performed to verify that the impact vibration test on the damaged concrete pier can be adopted for assessment of the bridge substructure integrity. Using the experimental modal analysis, the dynamic property changes of the concrete pier are investigated according to the damage levels which are modeled by the loss of cross section area of the pier body. As a result of the impact vibration test, it is found that the natural frequency of the bridge substructure is reduced due to the damage on the pier such as loss of cross section area, and the natural frequency can be used for assessment of the integrity index.