• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.3
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• pp.39-45
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• 2010

This paper deals with investigation on the spot for grounding systems of buildings based on international standards at construction sites. The investigation was carried out for grounding method, grounding type, shape of grounding electrode, grounding for a lightning protection system, continuity of steelwork in reinforced concrete structures, etc. The investigation on the spot was performed by a researcher and engineer with over fifteen years of industry experience all over the country. As a result of the investigation on the spot in 13 buildings, common grounding and structure grounding methods were dominant. The safety improvement methods include installation of equipotential bonding conductors for the connection to the main earthing terminal, equipotential bonding conductors for supplementary bonding, use of Surge Protective Devices (SPD), and safe connections between earthing conductors and the rebar.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.361-364
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• 2008

This paper deals with assessment of electrical safety for grounding system of buildings by investigation on the spot at construction site. The investigation was carried out for grounding method, grounding type, shape of grounding electrode, grounding for lightning protection system, continuity of steelwork in reinforced concrete structure and so on. The investigation on the spot was performed by researcher, engineer with over fifteen years of industry experience all over the country. As a result of investigation on the spot to 13 buildings, common grounding method was dominant. A new grounding system based on international standards includes unity grounding system, structure grounding utilizing steel reinforced concrete, equipotential bonding. use of surge protective device.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.99-105
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• 2007

This paper describes the investigation on the spot in relation to electrical safety of electrical installation in elementary middle high school. The investigation was carried out for power receiving system, classroom, chemistry room, music hall and so on. The investigation on the spot was performed by researcher, the related expert, engineer with over fifteen years of industry experience all over the country. As a result of investigation on the spot to 41 schools, common grounding methods at power receiving system were dominant. The risk factors include absence of control box of electric fan, non-installation of earth leakage circuit breaker to power source of experiment stand, use of non-grounding outlet.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.5
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• pp.92-97
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• 2011

This paper deals with the improvement of electrode installation for measurement of ground resistance through investigation on the spot in buildings. The investigation was carried out for an earthing terminal board for measurement of ground resistance, installation of auxiliary electrode, etc. The criteria value is set up by measuring method of ground resistance in international standard. In case of inadequate installation of auxiliary electrode, a relative error is analyzed and adequate installation method of auxiliary electrode is proposed. As a consequence, it is necessary to write direction of ground and equipment, and separate auxiliary electrode for measurement of ground resistance in order to minimize measuring error.

• Corrosion Science and Technology
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• v.13 no.4
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• pp.125-129
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• 2014

Shinning spot defects on galvanized steel sheets were studied by optical microscope, scanning electron microscope(SEM), Energy Dispersive Spectrometer (EDS) and Laser-Induced Breakdown Spectroscopy Original Position Statistic Distribution Analysis (LIBSOPA) in this study. The research shows that the coating thickness of shinning spot defects which caused by the substrate defect is much lower than normal area, and when skin passed, the shinning spot defect area can not touch with skin pass roll which result in the surface of shinning spot is flat while normal area is rough. The different coating morphologies have different effects on the reflection of light, which cause the shinning spot defects more brighter than normal area.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.83-95
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• 1991

This paper investigate into practice industrial safety consciousness and requirement for the spot workers in engaged the metal industry. Industrial accident defines "unwanted event" happened unexpectedly in opposition to hope workers and industrial accident is being possible to prevent. The purpose of this paper is to present a basic data for preventing and deceasing industrial accident from the spot works system by means of the improvement of worker's own safety consciousness and analyzing the spot worker's requirement in industrial safety.al safety.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.387-392
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• 2003

The mechanical behavior of two rectangular spot-welded plates under bending is investigated in detail. The equivalent thickness of spot-welded plates is introduced in this study and used in explaining the results. The focus of the analysis is to evaluate the effect of spot-welding from the view point of equivalent thickness. The investigation of deflection has been performed as comparing the result from finite element analysis with the measured data of the spot-welded plates for various parameters, such as aspect ratio, area ratio, and distance ratio of spot-welding points. The effect of spot-welding is as large as 62%(at r=1.0) when the area ratio of spot-welding point is just 4.52%.

• Journal of Welding and Joining
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• v.21 no.2
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• pp.70-75
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• 2003

Spot welding is a process that sheet metals are joined in one or more spot by heating at the faying interface. In this process, the spatter is dispersed from melted area. It has been reported that spatter generation has adverse effects on weld quality. However, no systematic study has been carried out to find out its effect on weld quality in resistance spot welding processes. In this study, specially designed specimen are used to perform experimental investigation of spatter generation and its effect. Major finding of this study show trends in tensile-shear strength for various amounts of spatter generated during spot welding process. Thus, optimum welding conditions are proposed in view of spatter generation and tensile-shear strength. (Received December 11, 2002)

• Research in Plant Disease
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• v.29 no.1
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• pp.60-63
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• 2023

During disease surveys from 2019 to 2021, the authors frequently encountered leaf spot symptoms on Fischer's ragwort plants growing at fields at six locations of Gangwon Province, Korea. The symptoms displayed brown to dark brown, circular or irregular spots on the plant leaves. The disease surveys at the six locations revealed 1-90% of diseased leaves of the plants. Phoma sp. was dominantly isolated from the diseased leaf lesions. Seven single-spore isolates of the fungus were selected and identified as Didymella ligulariae by investigation of their cultural, morphological, and molecular characteristics. Artificial inoculation test to Fischer's ragwort leaves was conducted with three isolates of D. ligulariae. The inoculation test revealed that the tested isolates cause leaf spot symptoms in the plants similar to the natural ones. The fungal pathogen has never been reported to cause leaf spot in Fischer's ragwort. Leaf spot of Fischer's ragwort caused by D. ligulariae is first reported in this study.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.107-110
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• 2005

The Purpose of this study was to asses the environmental friendless of apartments on the basis of the satisfaction of apartment residents. The apartments used for investigation was limited to the M apartment complex situated in Daegu. Both on-the-spot visit and questionnaire were used as the methods of investigation. The questionnaire was carried out on the spot by pre-trained junior students of Daegu University, and 212 questionnaires were collected. Investigation was performed from June 03, 2005 through June 06, 2005. The SPSS, a statistical program, was used for analysis.