• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.1093-1097
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• 1996

The Substitution development of 7075-T6 Al alloy to 7050-T74 Al alloy in small arms to improve anti-stress corrosion cracking was processed along with mass productivity consideration. To meet 7050 Al alloy material characteristics Indirect extrusion type was adopted and local heating above recrystalization temperature in forging process had to be avoided. The T74 aging treatment was 12$0^{\circ}C$ -6hrs and 175$^{\circ}C$ -12hrs and was appropriate for both machanical and anti-cohesion properties. In accessment of field application test 7050Al alloy made parts of small arms showed equivalent or better performance than 7075 Al alloy.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.4
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• pp.234-237
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• 2004

Measuring ground resistance has been a popular method of evaluation of the grounding electrode performance. If some portions of grounding electrodes are lost by corrosion, aging or other reasons, consequent deteriotation of the grounding performance would be resulted. It is one of the reasons why it is required to evaluate the performance of grounding systems regularly. However, in case of the electric facilities with multi-grounded system such as power substations with multi-grounded overhead ground wires and/or distribution line neutrals, it is practically difficult to disconnect neutrals or skywires from the substation grounding mesh for the ground resistance measurement. In this paper, a method for the grounding performance measurement of multi-grounded systems, which is based on the measuring ground current distributions, has been proposed. A field test results has shown the validity of the proposed test method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.306-310
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• 1996

In this paper a series of developing process for an insulator which can be employed in overhead distribution lines, using polymeric composite materials, is introduced. In order to design an insulator for heavily polluted area, weathershed of alternating type was adopted, which could have longer leakage distance. Modified EVA was used as surface material which has good electrical and mechanical characteristics as well as superior chemical stability. FRP core was covered with above surface material through heat shrinking process. By standardization of each process, higher productivity and lower production cost could be ensured. The developed insulator has been put under various tests including long-term field test and artificial aging test and satisfactory results were obtained.

• Nuclear Engineering and Technology
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• v.42 no.3
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• pp.313-318
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• 2010

Alnine pellets were installed in a nuclear power plant for one or two operation cycles and measured by electron spin resonance (ESR) spectrometers for dosimetry. Dose and "x/y ratio", i.e., satellite peak over main center peak ratio, were measured for the returned alanine dosimeters from the nuclear power plant and compared to the values of reference alanine dosimeters exposed only to gamma rays. The variation of the x/y ratio change depended on the population of radicals from each radiation component with different LET. The gamma dose in a mixed radiation field was estimated by an additive gamma ray irradiation experiment and the measured dose rate at specified locations in the containment building.

• Electronics and Telecommunications Trends
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• v.32 no.6
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• pp.27-39
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• 2017

A variety of medical devices are utilized to repair or help injured body functions after accidental injury(such as a traffic accident), population aging, or disease. Such medical devices are being actively researched and developed in portable form, skin patchable type, and further, implantable form. In the future, active implantable medical devices for neuro and brain sciences are expected to be developed. Active implantable medical devices that detect brain signals and control neurology for a wider understanding of human cognition and nerve functions, and for an understanding and treatment of various diseases, are being actively pursued for future use. In this paper, the core elements of implantable devices that can be applied to neuro and brain sciences are classified into electrode technologies for bio-signal acquisition and stimulation, analog/digital circuit technologies for signal processing, human body communication technologies, wireless power transmission technologies for continuous device use, and device integration technologies to integrate them. In each chapter, the latest technology development trends for each detailed technology field are reviewed.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.4
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• pp.234-234
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• 2004

Measuring ground resistance has been a popular method of evaluation of the grounding electrode performance. If some portions of grounding electrodes are lost by corrosion, aging or other reasons, consequent deteriotation of the grounding performance would be resulted. It is one of the reasons why it is required to evaluate the performance of grounding systems regularly. However, in case of the electric facilities with multi-grounded system such as power substations with multi-grounded overhead ground wires and/or distribution line neutrals, it is practically difficult to disconnect neutrals or skywires from the substation grounding mesh for the ground resistance measurement. In this paper, a method for the grounding performance measurement of multi-grounded systems, which is based on the measuring ground current distributions, has been proposed. A field test results has shown the validity of the proposed test method.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.107-111
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• 2015

Our work is based on the development of a numerical model to develop a methodology for predicting the aging and breakdown in insulation due to the dynamics of space charge packets. The model of bipolar charge transports is proposed to simulate space charge dynamic for high DC voltage in law-density polyethylene (LDPE), taking into account the trapping and detrapping of recombination phenomena, this model has been developed and experimentally validation. Theoretical formulation of the physical problem is based on the Poisson, the continuity and the transport equations as well as on the appropriate models for injection. Numerical results provide temporal and local distributions of the electric field, the space charge density for the different kinds of charges, conduction and displacement current densities, and the external current.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.426-431
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• 2004

Leaking water coolant into stator electrical insulation is a growing concern for the aging water-cooled generator since leaks in the generator water-cooled stator winding can affect machine availability and insulation life. But a domestic techniques of such field are insufficient and depend wholly on GE or TOSHIBA technique. Therefore this paper introduces measuring principle and developed measuring system, which has been used to detecting wet absorption. We accomplished the experiment with a stator promotion of virtue which is used in actual power plant. Also, Experimental method of generator stator winding, which is investigated into wet absorption test.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.86-91
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• 2002

Glass/phenolic composite laminates have been used in the field of non-flammable light rail transit and their applications have expanded more widely. Low velocity impact tests have been used to evalute the effect of temperature and acceleration aging on low velocity impact response of phenolic matrix composites reinforced with woven E-glass fabric. The damage of matrix cracking and delamination are suddenly reduced the compressive strength after impact. The damage area increases with increasing temperature and impact energy. UT C-scan is used to determine damage areas by impact loading. Therefore, all this observations indicate reduced impact damage resistance and damage tolerance of the laminates at elevated temperature.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2005.05a
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• pp.249-250
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• 2005

Since Korea has already become the 'aging society' and is expected to become the 'aged society' by 2019, development of the facilities and dedicated housing for the senior citizens have become the key issues. The growing population of the older people, changed in the social structure, family type, and the way of living brings a moment to consider the various aspects to support the older people. The purpose of this research is to analyze the interior color characteristics. Based on the research will provide a direction for color planning of elderly housing facilities in Korea. For this purpose, a field survey was conducted between October 17-21 in Japan. The research method employed was an empirical case study visiting 6 senior housing facilities in Japan, Osaka area. First, the brightness used in the senior housing facilities in Japan ranges from high value to low value while the chroma ranges from the middle chroma to low chroma. The warm colors of Y, YR and R are mainly used.