• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.41-46
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• 2010

With the improvement of industrial society, high quality electrical energy, simplification of operation and maintenance, and ensuring reliability are being required. Also we request an urgent change from $SF_6$ gas to an environment-friendly gas insulation material. In this paper, the experiments of breakdown characteristics by pressure and gap change of $N_2/O_2$ mixture gas through a GIS (Gas Insulated Switchgear) model were described. This paper reviews basic data of the surface discharge characteristics for Teflon resin in not only pure $N_2$, $N_2:O_2$ mixture gas as being focused on environmentally-friendly insulating gas, but also $SF_6$. Also, insulation characteristics by breakdown voltage and surface discharge voltage of $N_2:O_2$ mixture gas in the experimental chamber were studied.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.824-827
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• 1995

Dielectromagnets are permanent magnets made from resin-bonded hard magnetic powders. Magnetic properties of dielectromagnets depend on kind of used hard magnetic materials as chemical compound, shape, size of grain and applied technology. Comparison of advantages and disadvantages of dielectromagnets made from different kind of magnetic powders induced us to try to prepare dielectromagnets from mixture of hard magnetic powders, not only one of them. The purpose of investigation on this kind of dielectromagnets is to find formula to prepare permanent magnets with properties adequate to different kind of electrical motors requirements. As hard magnetic materials we used powders of ferrite, melt-spun ribbon Nd-Fe-B and Alnico. Papers present results of investigation on technology of this kind of dielectromagnets. It shows also influence of kind of mixture and used technology on magnetic properties of dielectromagnets.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.181-182
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• 2023

The purpose of this study is to enhance the photocatalytic properties of a mixture of low-cost titanium dioxide and calcium carbonate through a simple mixing process. To increase the photocatalytic activity, the weight ratio of titanium dioxide to calcium carbonate was selected as a variable. Photocatalytic activity was evaluated by measuring the degradation of methylene blue and NOx under ultraviolet light. The results showed that a mixture containing 60% titanium dioxide and 40% calcium carbonate exhibited the highest photocatalytic activity.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.277-282
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• 2003

Computational calculations are now successfully introduced to design liquid crystal molecules for uses in modern active-matrix displays. These material technologies are practically applied to develop novel compounds, enabling formulation of advanced liquid crystal mixtures together with a newly developed mixture purification method. Typical examples of these liquid crystal mixtures are introduced for modern displays in various applications.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.310-317
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• 2022

The mass attenuation coefficient is the primary physical parameter to model narrow beam gamma-ray attenuation. A new machine learning based approach is proposed to model gamma-ray shielding behavior of composites alternative to theoretical calculations. Two fuzzy logic algorithms and a neural network algorithm were trained and tested with different mixture ratios of vanadium slag/epoxy resin/antimony in the 0.05 MeV-2 MeV energy range. Two of the algorithms showed excellent agreement with testing data after optimizing adjustable parameters, with root mean squared error (RMSE) values down to 0.0001. Those results are remarkable because mass attenuation coefficients are often presented with four significant figures. Different training data sizes were tried to determine the least number of data points required to train sufficient models. Data set size more than 1000 is seen to be required to model in above 0.05 MeV energy. Below this energy, more data points with finer energy resolution might be required. Neuro-fuzzy models were three times faster to train than neural network models, while neural network models depicted low RMSE. Fuzzy logic algorithms are overlooked in complex function approximation, yet grid partitioned fuzzy algorithms showed excellent calculation efficiency and good convergence in predicting mass attenuation coefficient.

• Applied Microscopy
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• v.43 no.1
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• pp.40-45
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• 2013

Phase transformation by the Mn-deprivation was observed in the high-Mn twinning-induced plasticity-aided steel. Mn-depletion was induced by the formation of Mn-O oxide during the dew-point control process at temperature above $-20^{\circ}C$, which changed austenitic parent phase to multi-grained ferrite. Mixture of Al-O, Al-Mn-Si-O oxides were observed at the grain boundaries of transformed ferrite.

• Journal of Welding and Joining
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• v.24 no.4
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• pp.15-21
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• 2006

The aim of present study is to investigate the effect of welding parameters and heat treatment conditions on the formability of the $CO_2$ laser welded silicon steel sheet. It was found that there is optimum range of the heat input ($0.6{\sim}0.7kJ/cm$) and gap distance ($0.125{\sim}0.150mm$) for the high tensile strength and the avoidance of the fracture in weld metal. Also, it was essential fur the improvement of formability to perform pre- and post-welding heat treatment which cause the uniform mixture of base metal and welding consumable.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.461-463
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• 2012

본 연구는 실시간 영상에서 정면 얼굴을 가지고 있는 이미지를 탐지하는 방법에 대한 것이다. 모든 프레임마다 얼굴 인식 등의 연산을 수행한다면 계산량과 시간이 문제이다. 우리가 제안하는 방법은 동일인이 등장하는 영상 중 동일한 얼굴을 추적하여 움직임의 차이를 이용하여 정면 이미지를 판단하는 것이다. Gaussian Mixture Model 과 Motion template 을 이용하였으며, 실험을 통해 도출된 결과는 제안 알고리즘의 유용성을 어느 정도 증명할 수 있었다.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.1 s.113
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• pp.45-53
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• 2006

This study was carried out to produce high functional and biodegradable coating agents for pulp mold by evaluating various kinds of biodegradable polymers. Five kinds of biodegradable polymers were used. In addition, the mixture of the carboxymethylated starch and biodegradable polymers(${\kappa}$-carrageenan, chitosan) were used for mixed coating agents. Physical properties of coated paperboards were evaluated. Conclusions obtained were as follows. 4% ${\kappa}$-carrageenan and 5% chitosan showed higher water and oil resistance. 10% sodium alginate, 4% corn zein and 15% polycaprolactone showed high water resistance while no improvement was found on oil resistance. The optimum mixture ratios for the mixed coating agents were 90:10(carboxymethylated starch : ${\kappa}$-carrageenan) and 50:50(carboxymethylated starch : chitosan). Since these mixed coating agents have excellent biodegradability with higher water and oil resistance, these can be used for the environmental-friendly coating agents.

• Journal of Welding and Joining
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• v.29 no.1
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• pp.90-98
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• 2011

Al-Si coated Boron steel and Zn coated DP steel were welded using DISK laser and the microstructure and hardness of the weld were investigated. Full penetration was obtained, when the welding speed was lower than 4m/min. In the specimen welded with laser power of 3 kW and welding speed of 2 m/min, the hardness was the highest in the heat affect zone in the boron steel (HAZ-B) and that of the heat affect zone in the DP steel (HAZ-D) was lower than HAZ-B. The hardness of fusion zone was in between those of HAZ-B and HAZ-D. The decreased hardness from each HAZ to base metal(BM) could be explained that ferrite contents increases when access to the BM. The variation of hardness in the welds could be explained by the difference of microstructure, that is, full martensite in HAZ-B, mixture of martensite and bainite in the fusion zone, and the mixture of martensite, ferrite and bainite in HAZ-D.