• 대한교통학회지
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• 제35권3호
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• pp.210-219
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• 2017

친환경 교통수단으로 주목받고 있는 전기자동차는 우리나라에서도 2011년부터 지속적으로 보급대수가 증가하고 있다. 전기자동차 보급에 따라 충전 인프라 확대를 위하여 본 논문에서는 전기자동차 보급률이 높고 충전인프라가 비교적 잘 구축되어 있는 제주도 사례를 바탕으로 충전소 이용행태를 분석하여 기존 충전소의 효율적 운영방안과 추가적인 충전시설 설치 시 고려할 요소에 대하여 분석하고자 하였다. 전기자동차 충전소가 있는 읍면동별 급속충전기와 완속충전기 이용특성과 시설의 유형에 따라 시간대별 이용특성을 분석하였다. 제주도에 설치된 충전기의 이용 빈도를 분석한 결과, 급속충전기와 완속충전기 이용 빈도 모두 특정지역에 편중된 이용률이 나타났다. 유형별 충전소 이용은 급속충전기와 완속충전기 모두 업무시설과 공영주차장에 설치된 충전기 이용률이 높았으나, 시간대별 이용률을 보면 급속충전기는 오후시간 전반에 걸쳐 이용률이 높은 반면, 완속충전기 이용은 오전시간에 집중되어 있었다. 이러한 이용특성을 반영하여 이용자들이 전기자동차 충전소를 효율적으로 이용할 수 있도록 이용률이 낮은 충전소를 안내하는 홍보방안과 충전기를 이용할 때에 주의사항 및 충전완료 알림서비스 등을 제공하는 것이 필요할 것이다. 또한, 아직 충전기가 설치되지 않은 지역을 충전기 설치대상지역으로 고려하고, 이에 더불어 충전기 이용률이 높은 지역과 시설에 추가 설치가 이루어져야 한다. 실제 전기자동차 충전행태 분석 결과를 활용하여 실질적인 서비스 향상이 가능할 것으로 기대된다.

• 동력기계공학회지
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• 제19권5호
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• pp.60-66
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• 2015

Embrittlement of material by hydrogen charging should be cleared for safety of storage vessel of hydrogen and components deal with hydrogen. A stainless steel is generally used as materials for hydrogen transportation and storage, and it has a big advantage of corrosion resistance due to nickel component in material. In this study, microscopic damage behavior of stainless steel according to the hydrogen charging time using nondestructive evaluation was studied. The surface of stainless steel became more brittle as the hydrogen charging time increased. The parameters of nondestructive evaluation were also changed with the embrittlement of stainless steel surface by hydrogen charging. Ultrasonic test, which is the most generalized nondestructive technique, was applied to evaluate the relationship between the ultrasonic wave and mechanical properties of stainless steel by hydrogen charging. The attenuation coefficient of ultrasonic wave was increased with hydrogen charging time because of surface embrittlement of stainless steel. In addition, acoustic emission test was also used to study the dynamic behavior of stainless steel experienced hydrogen charging. AE event at the hydrogen charged specimen was obviously decreased at the plastic zone of stress-strain curves, while the number of event for the specimen of hydrogen free was dramatically generated when compared with the specimens underwent hydrogen charging.

• Macromolecular Research
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• 제8권1호
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• pp.6-11
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• 2000

In this study, we examined the charging behavior of chopped carbon fibers during electro-flocking process, which is one of the key processes of the novel technique for fabricating conductive polymer composite films. Short carbon fibers (CF) during electroflocking were electrically charged by the combined effect of contact charging, corona charging and tribocharging. The specific charge built on CF surface was measured by using Faraday cup method. Specific charge increased not only with increasing electric field strength and potential impressed to mesh electrode as expected from theoretical considerations in literature, but with decreasing mesh opening size due to the improved contact charging condition. However, CF length was found unexpectedly to influence the amount of CF specific charge due to the agglomerated nature of CF flocks leading to the change in charging conditions.

• 한국재료학회지
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• 제20권11호
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• pp.581-585
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• 2010

High strength sheet steels for automobile are seriously compromised by hydrogen embrittlement. This issue has been continuously studied, but the field of interest, which lies between microstructural characteristics and hydrogen behavior with hydrogen charging, has not yet been thoroughly investigated. This study was done to investigate the behavior of hydrogen according to the hydrogen volume fraction on 590MPa grade DP steels, which are developed under hydrogen charging conditions as high strength sheet steels for automobiles. The penetration depths and the mechanical properties, according to charging conditions, were investigated through the distribution of micro-hardness and the microstructural observation of the subsurface zone. It was found that the amount of hydrogen trapping in 590MPa DP steels was related to the austenite volume fraction. It was confirmed that the distribution of micro-hardnesses according to the depth of the subsurface zone under the free surface showed the relationship of the depth of the hydrogen saturation between the charging conditions.

• 한국수소및신에너지학회논문집
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• 제21권4호
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• pp.340-345
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• 2010

For the conversion into hydrogen society, not only studying facilities of hydrogen production, storage, transportation and charging system but also developing technique of ensuring safety are essentially needed. Hence, for the first step of that, evaluated the hydrogen embrittlement of Inconel alloy 617, Ni-based super heat-resisting alloy, by small punch test. Prepared the various specimens through changing electrochemical charging time and measured the toughness degradation of the specimens by small-punch test. The analysis of hydrogen embrittlement behavior were carried out by investigating the fractured surface of specimens. This study has significance on revealing mechanism of hydrogen embrittlement behavior and the factor affecting hydrogen embrittlement in the future study.

• 한국재료학회지
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• 제31권2호
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• pp.84-91
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• 2021

To cope with automobile exhaust gas regulations, ISG and charging control systems are applied to HEV vehicles for the purpose of improving fuel economy. These systems require quick charge-discharge performance of high current. Therefore, a Module of the AGM battery with high energy density and EDLC(Electric Double Layer Capacitor) with high power density are constructed to study the charging and discharging behavior. In CCA, which evaluates the starting performance at -18 ℃ & 30 ℃ with high current, EDLC contributed for about 8 sec at the beginning. At 0 ℃ CA (Charge Acceptance), the initial Charging current of the AGM/EDLC Module, is twice that of the AGM lead acid battery. To play the role of EDLC during high-current rapid charging and discharging, the condition of the AGM lead-acid battery is optimally maintained. As a result of a Standard of Battery Association of Japan (SBA) S0101 test, the service life of the Module of the AGM Lead Acid Battery/EDLC is found to improve by 2 times compared to that of the AGM Lead Acid Battery.

• 설비공학논문집
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• 제9권3호
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• pp.323-332
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• 1997

It was reported by some researchers that two-stage parallel-plate ESPs, commonly called electronic air cleaners, show decreasing behavior of collection efficiency as particle size decreases below about $0.03{\mu}m$. This phenomenon is attributed to partial particle charging characteristics, where some of incoming particles are not charged in the charging cell of 2-stage parallel-plate ESP. One way to improve the decreasing collection efficieny in that particle size range is to enforce particle charging quantity in the charging cell. In the present study, in order to do this a 2-wire series-type charging cell modified from a 1-wire normal-type one was suggested and investigated theoretically and experimentally concerning improvement of the collection efficiency. It was confirmed from the experimental and theoretical works that the collection efficiency was apparently improved.

• 한국표면공학회지
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• 제46권5호
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• pp.229-233
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• 2013

The small punch(SP) tests that can be applied to high strength sheet steel in automobile were carried out to evaluate the behavior of hydrogen embrittlement of DP sheet steels. In order to charge hydrogen at DP sheet steels, DP sheet steels were treated by the electrochemical hydrogen charging method under the charging conditions of current densities of 100, 150 and 200 $mA/cm^2$ for charging times of 5, 10, 25 and 50 hrs. Respectively, After hydrogen charging with experimental conditions, SP tests were performed. From the SP results, the correlations between the variation of bulb diameters and bulb heights with the hydrogen charging conditions were analysed. It was shown that the variation of bulb diameters were not significant with the hydrogen embrittlement due to the amounts of hydrogen charging. On the other hand, the bulb heights were observed to decrease with increasing hydrogen contents. It was thought that these results of the variation of bulb shapes after SP tests would be estimated as the index of evaluation of hydrogen embrittlement.

• 한국초전도ㆍ저온공학회논문지
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• 제20권4호
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• pp.16-19
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• 2018

This paper presents analytical and numerical simulation approaches on charging characteristics of no-insulation (NI) REBCO pancake coil by using the equivalent circuit model to estimate magnetic performance response in the coil. The analytical methods provide closed form or definite solution in the form of complete mathematical expressions but they are hard to solve the complex problems. Numerical methods have become popular with the development of the computing capabilities to solve the problems which are impossible or very hard to solve analytically. First of all, the equivalent circuit model are proposed to develop the simulation code for both analytical and numerical method. The charging test was performed under critical current to obtain magnetic field induced and terminal voltage through the radial as well as spiral current paths within the coil. To verify the validity of both proposed methods, the simulation results were compared and discussed with the experimental results.

• 디지털산업정보학회논문지
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• 제14권4호
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• pp.229-239
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• 2018

In this paper, we propose a strategy of charging by analyzing the difference of path coefficient according to whether consumers are free or not, rather than presenting strategies for charging. Mobile devices have become so popular that they are called necessities. Companies have to adapt to the mobile environment and respond to the situation, and have to expand market opportunities strategically. In this study, we extend the technology acceptance model to analyze the incentives of consumers' behavior by analyzing the difference in the effect consumers perceive as a moderating variable, whether paid or free. Efforts to maximize company's inherent profit continue, and in particular, charging is a strategy that all companies should pursue in the mobile environments. It is necessary to grasp the degree of the consumer's response to free and charge. The model of satisfaction with the continuous use and the word-of-mouth intention, which is the behavior intention, is presented by adding parameters of satisfaction to the technology acceptance model. In addition, we try to derive implications by analyzing the influence of moderating effects of whether free or not.