• Journal of Power Electronics
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• v.9 no.1
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• pp.68-73
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• 2009

Automotive inverters may require current sensors for motor torque control, especially, in applications of hybrid electric vehicles or fuel cell vehicles. In this paper, to achieve a compact, integrated and low cost current sensor, a hall current sensor without magnetic core is introduced for integrating an automotive inverter. The compactness of the current sensor is possible by using integrated magnetic concentrators based on the Hall effect. Magnetic fields caused by three-phase currents are analyzed and a magnetic shield design is proposed for decoupling the cross-coupled field. It offers galvanic isolation, wide bandwidth (>100kHz), and accuracy(< 1%). Using 2D FEM analysis, its performance is demonstrated with design parameters at a U-shaped magnetic shield. The proposed coreless current sensor is tested with rated current to validate the linearity and accuracy.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.370-372
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• 2003

As there expands the usage of Al-Cu connections to interface aluminum and copper in power distribution systems, efforts to mitigate the mechanical, electrical or electro-chemical degradation are widely spreading. The explosive bending technology, in particular, has been thought as a countermeasure for the degradation. In this paper, electrochemical analysis and optical microscopic observation are carried out in order to compare the corrosion resistivities of the commercial compression type bimetallic sleeve and the explosion type bimetallic sleeve. The results show that the explosive bonding technology can prevent the interfacial corrosion caused by the formation of crevices and pits as well as from galvanic potential difference.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.11a
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• pp.443-447
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• 1999

최근들어 제품개발에 앞서 제품으로 인해 유발되는 감성을 측정하기 위한 시도가 늘고 있다. 그러나 제품을 사용하면서 나타나는 행동의 변화는 많은 영향 요소를 포함하고 있어 이를 해석하기가 어렵다. 본 연구는 안정을 유도하는 Herb차를 개발하거나 치약과 같이 사용으로 인한 감성유발 효과를 보고싶어하는 요구에 따라 시행하였다. 우선 실험전 피검자의 불안 척도, 기본 check list에 따라 피검자를 선택하였다. 또한 객관적 감성 지표로는 Fz, Fp1, Cz, Oz에서 뇌파를 측정하였고 EOG를 시행하여 noise를 제거하였다. 자율신경계 반응으로 galvanic skin resistance(GSR), 피부온도, 심박수등을 동시에 측정하였다. 이들 제품 사용으로 인한 객관적 감성 변화의 대조군으로는 행동 시행전에 측정하였다. 제품 사용 후 10분 간격으로 30-60분까지 나타나는 변화를 측정하였으며, 이들 제품들은 안정 효과를 유도하고자 기획되었으므로 대조군으로 00 $\times$ 0의 복잡한 계산문제를 주어 stress로 인한 감성, 걷는 동작, 손 씻는 행위등을 나누어 측정하였다. 본 연구의 결과에 의하면, 제품 사용으로 인한 감성의 변화는 GSR에서 가장 잘 반영되었고 또한 계산 문제로 인한 자극에서도 역시 GSR의 변화가 가장 뚜렷하였다. Herb차인 경우 기호도에 따른 차이가 나타났음을 알 수 있었다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.421-422
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• 2015

Nowadays, bidirectional DC-DC converters are becoming more into picture for different applications especially electric vehicles. There are many bidirectional DC-DC converters topologies; however, voltage-fed Dual Half-Bridge (DHB) topology has less number of switches as compared to other isolated bidirectional DC-DC converters. Furthermore, voltage fed DHB has galvanic isolation, high power density, reduced size, high efficiency and hence cost effective. Electrolytic capacitors always have problem regarding size and reliability in DC-AC single phase inverters. Therefore, voltage-fed DHB converter is proposed for the purpose of power decoupling to replace electrolytic capacitor by film capacitors. A new control strategy has been developed for 120Hz ripple rejection, and it was verified by simulation.

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.47-53
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• 2005

The E.M.F. of the galvanic cell with fused salt was measured to determine the activities of zinc at 720-860 K over the entire composition range of liquid Zn-In and Zn-Sn alloys. The cell used was as follows: $$(-)W{\mid}Zn(pure){\mid}Zn^{2+}(KCl-LiCl){\mid}Zn(in\;Zn-In\;or\;Zn-Sn\;alloy){\mid}W(+)$$ The activities of zinc in the alloys showed positive deviation from Raoult's law over the entire composition range. The activity of cadmium and some thermodynamic functions such as Gibbs free energy, enthalpy and entropy were derived from the results by the thermodynamic relationship. The comparison of the results and the literature data was made. The liquid Zn-In and Zn-Sn alloys are found to be close tn the regular solution. The concentration fluctuations in long wavelength limit, $S_{cc}(o)$, in the liquid alloy were calculated from the experimental results.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.452-455
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• 1999

ORV which vaporizes LNG to NG is consisted of tube and header whose substrate is aluminum alloy. The corrosion of the tube is very severe because of sea water being used as the heating source. In this research to protect ORV substrate material, the corrosion behavior of aluminum alloys was investigated for the sacrificial role of Al-Zn alloy for ORV tubes. The electrochemical behavior of aluminum alloys in sea water was investigated. The corrosion behavior of thermally-sprayed and cladded samples were compared through salt spray tests. Al-Zn alloy can act as a sacrificial anode and cladded Al-Zn alloy has a better corrosion resistance than that of thermally sprayed one. The galvanic effect of Al-Zn to substrate material was conformed from scratched sample tests.

• Corrosion Science and Technology
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• v.22 no.5
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• pp.305-313
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• 2023

The objective of this study was to investigate the effectiveness of sodium dodecyl benzene sulfonate (SDBS) as a corrosion inhibitor on the pitting corrosion behavior of aluminum alloys used in electric vehicle battery cooling systems within a mixture of ethylene glycol and water (EG-W) coolant. Potentiodynamic polarization testing revealed unstable passive film formation on the aluminum alloys in the absence of SDBS. However, the addition of SDBS resulted in a robust passive film, enhancing the pitting corrosion resistance across all examined alloys. Pitting corrosion was predominantly observed near intermetallic compounds in the presence of Cl? ions, which was attributed to galvanic interactions. Among tested alloys, A1040 demonstrated superior resistance due to its lower areal fraction of precipitates and donor density. The incorporation of SDBS inhibitors mitigated the overall pitting corrosion process by hindering Cl? ion penetration. These findings suggest that SDBS can significantly improve pitting corrosion resistance in aluminum alloys employed in battery coolant environments.

• Science of Emotion and Sensibility
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• v.12 no.3
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• pp.279-288
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• 2009

The purpose of this study was to verify the impact of cognitive factors and GSR on the task performance. For this study 64 students participated. Multiple regression and repeated measures were applied to analyze the data. The result for the survey indicated that previous knowledge, physical efforts, and task difficulty had significant impacts on task performance. Particularly, task difficulty has a negative impact. This can be interpreted as someone who has high prior knowledge inputs higher physical efforts with low task difficulty perception will show high performance. On the other hand, the low arousal level of GSR in the evaluation stage is a prediction variable of task performance. This result shows that high prior knowledge and low arousal level of GSR produces high performance. However, the analysis of difference in GSR between learning and evaluation stages does not show significant difference. It suggests that physiological measure such as GSR is reliable index of cognitive load; however, it partially represents cognitive load. Other crucial factors should be added for comprehensive measures.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.65-71
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• 2017

To prepare the Cu-based filler material indicating enhanced oxidation resistance property and Ag content, Ag-coated Cu particles was fabricated by Ag plating of 40 wt % on the spherical Cu particles with an average size of $2{\mu}m$ and their oxidation behavior was also evaluated. In the case that ethylenediaminetetraacetic acid was used alone, the fabricated particles frequently showed broken structures such as delamination at Ag shell/core Cu interface and hollow structure that are induced by excessive galvanic displacement reaction. As a result, fraction of defect particles increased up to 19.88% after the Ag plating of 40 wt.%. However, the fraction in the 40 wt.% Ag-coated Cu particles decreased to 9.01% and relatively smooth surface and dense microstructure in the Ag shell were also observed with additional usage of hydroquinone as a complexing agent. Ag-coated Cu particles having the enhanced microstructure did not show any weight increase by oxidation for exposure to air at $160^{\circ}C$ for 2 h, indicating increased oxidation resistance property.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.11-18
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• 2015

Stress is one of the major causes threatening the mental and physical health of human today. In this paper, we analyzed the heart rate variability(HRV), galvanic skin response(GSR), and skin temperature data measured from the university subjects before and after the class to examine the influence on bio-signal in stress environment. Thirty subjects from university students (aged between 21 and 27 years; mean=22.31, STD=1.45) took part in this study. From the experiment results, RMSSD(p=0.033), LF peak(p=0.003), VLF(p=0.045) were statistically significant from those of the control group(p<0.05) of HRV both in time and frequency domain. We observed that mean skin conductivity after the class(mean=5.993(uS), SD=3.406) is higher than that before the class(mean=3.039(uS), SD=2.628) by 97.2% on average and the skin temperature after the class($34.835{\pm}0.305$) is slightly higher than that before the class($34.471{\pm}0.281$) by 1.055% on average. The results in this research could be used to examine the autonomic response in clinical stress related research.