• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.686-689
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• 2005

This study was conducted to investigate the effect of ammonium and nitrate nitrogen removal to applied voltage, electrolytic time and activated carbon packing height. Batch bipolar packed bed electrolytic cell reactor was packed with $4{\times}8$ mesh granular activated carbon (GAC). Afterward electrolysis was performed in 20 V for 30 min. As a result, as the filling height adjusted to 80 mm high, the removal efficiency of ammonium nitrogen was 99.9%. and as the electrolytic time varied to 60 min, the removal efficiency of ammonium nitrogen was 97.6%. and in case of continuous electrolytic treatment of ammonium and nitrate nitrogen removal efficiency of total nitrogen was over 80% in bipolar packed bed electrolytic cell reactor for 72 hours as the packing height, sample concentration and input rate of sample adjusted to 280 mm, 30 mg/L, 6.7 mL/min, respectively.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.1
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• pp.31-36
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• 2011

Ubiquitous network and wireless sensor networks is being applied in various fields. Located at target areas, node of wireless sensor network uses batteries as a power source. Batteries have a limited energy in sensor network applications. Also, before use, the battery must be charged and It is difficult to replace the battery. Therefore, energy harvesting technology is being researched and being developed for long life of sensor node. Especially, sola energy is being extensively researched. because that can have great amounts of energy than other environmental energy in a short time. In this study, we tested battery charging and recharging, operation of sensor node using Solar Cell. Also, monitoring data gathering and voltage Analysis showed energy harvesting time of Sola Cell battery for sensor node and operation of sensor node.

• Polymer(Korea)
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• v.27 no.1
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• pp.61-68
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• 2003

In this study, we have investigated the preparation of mixed bead and fiber type hybrid ion-exchanger for recovering nickel ion from plating rinse water. There was little dependence of adsorption capacity for nickel ion on the mixing ratio of resin type and fiber type of ion exchangers. However, it increased with increasing the resin content in the mixed bed. It was shown that the data Langmuir and Freundlich's adsorption isotherm model were well fitted to the linear. Affinity between the functional groups in the ion exchanger and nickel ion in the process was confirmed. The pressure drop decreased with increasing the number of stage in the multistage bed, but it increased with increasing the resin content in the mixing bed. The initial breakthrough time in the multistage bed was short due to the increase of number of stage in the continuous process. It was found that the final breakthrough time of the multistage bed was little changed. The breakthrough time decreased with increasing the amount of fibrous ion exchanger in the mixed bed. The maximum adsorption capacities of the mixed and multistage beds were 2.51 meq/g and 2.69 meq/g, respectively. The desorption time for the nickel ion with $1N H_2SO_4$ solution was lower than 10 minutes and the yield of desorption was greater than 98 percent.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1278-1279
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• 2011

본 논문은 KEPCO에서 개발되어 실증이 완료된 3가지 종류의 충전기에 대해 설명한 것이다. 전기자동차용 충전기는 충전시간 및 용량에 따라 급속충전기, 완속충전스탠드, 홈충전기로 분류할 수 있으며, 설치장소 및 용도를 고려하여 설치하는 것이 바람직하다. 따라서 급속충전기는 50[kW]급의 기본형과 100[kW]급의 분리형으로, 완속충전스탠드는 7.7[kW]급의 기본형과 15.4[kW]급의 2소켓형으로, 홈충전기는 3.3 [kW]급의 단독형과 7.7[kW]급의 공동형으로 나누어 개발하도록 하였다. 본 논문에서는 이러한 충전기들을 정의하고, 구성을 설명하며, 기능 및 사양을 제시하고자 한다. 이를 통해 KEPCO에서 개발된 충전기와 충전기술 등이 국내 전기자동차 시장 활성화와 충전인프라 조기구축에 기여할 수 있음을 보이고자 한다.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.52-53
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• 2011

현재 화석연료의 고갈과 이산화탄소의 배출로 인한 지구 온난화 문제로 인하여 전기 자동차의 연구가 활발히 진행 중에 있다. 본 논문에서는 전기 자동차용 배터리 충전 시스템의 급속충전 방식을 연구한다. 본 연구에서 사용하는 급속충전 방식은 기존의 CV/CC(정전압/정전류)제어 방식에서 CC모드를 충분히 확보하여 충전시간을 단축하는 방식으로 실험을 통해 그 동작을 검증한다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.2
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• pp.94-101
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• 1997

This paper proposes the equalizing charger of series connected batteries which are controlled by the time-sharing method. One-chip microprocessor dectcts the terminal voltage of each battery and then determines the charging time inversely proportional to the terminal voltage so that it decrease the un¬balanced capacity. This system is compact and light, therefore it can be applied to portable equipment such as charger for electric vehicle. And it's so effective as to prevent from overcharging which causes their life to shorten.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.217-218
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• 2009

This experimental work is to verify the previously developed prediction model for self-consolidating concrete (SCC) formwork pressure. A new apparatus was devised to simulate formwork pressure in laboratory, and experiments were performed for one SCC mix. The predicted pressure with the calibrated parameters were compared with the pressure measured under continuous and discrete pouring. The calibrated parameters have a specific trend over loading time, and the calculated pressure accurately simulates the real pressure varying over time.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.01a
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• pp.129-130
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• 2020

공중장소에서 충전기에 꽂힌 상태로 무방비로 도난의 위협에 방치되어있는 스마트폰들을 아주 쉽게 발견할 수 있다. 잃어버린 스마트폰은 다시 구매하면 되지만 혹시라도 미처 백업하지 못한 자료나 연락처 등의 소중한 정보의 손실로 인해 피해는 클 것이다. 공중장소에서 충전중인 스마트폰을 절도를 목적으로 무단으로 전원에서 분리할 가능성에 대비하여 경고화면을 보여주는 한편, 만일 무단으로 충전기에서 뽑거나 케이블을 절단하면 경보를 울리는 한편, 현재 위치의 위도와 경도를 SMS기능을 사용해 지정한 전화번호로 해당 정보를 전송하는 기능을 안드로이드에 구현하였다. 이를 통해 도난이 되더라도 스마트폰을 잃어버린 위치와 시간을 특정 할 수 있게 도와 줄 수 있기 때문에, 도난이 의심되는 해당 시설 또는 근처의 CCTV영상을 확보하여 범인을 빨리 특정할 수 있게 함으로써 최대한 빠르게 스마트폰을 되찾을 수 있는 확률을 높여주고, 스마트폰에 대한 절도억제 효과도 줄 수 있다.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.543-551
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• 2015

Quick-hardening track (QHT) is a construction method which is used to change from old ballast track to concrete track. Sufficient time for construction is important, as the construction should be done during operational breaks at night. Most of the time is spent on exchanging the ballast layer. If it is possible to apply the ballast non-exchange type of quick-hardening track, it would be more effective to reduce the construction time and costs. In this paper, pouring materials with high permeability are suggested and a construction method involving a layer separation pouring process considering the void condition is introduced in order to develop ballast non-exchange type of QHT. The separate pouring method can secure the required strength because optimized materials are poured into the upper layer and the lower layer for each void ratio condition. To ensure this process, a rheology analysis was conducted on the design of the pouring materials according to aggregate size, the aggregate distribution, the void ratio, the void size, the tortuosity and the permeability. A polymer series was used as the pouring material of the lower layer to secure the void filling capacity and for adhesion to the fine-grained layer. In addition, magnesium-phosphate ceramic (MPC) was used as the pouring material of the upper layer to secure the void-filling capacity and for adhesion of the coarse-grained layer. As a result of a mechanics test of the materials, satisfactory performance corresponding to existing quick-hardening track was noted.

• Proceedings of the Korean Society of Computer Information Conference
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• 2024.01a
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• pp.485-488
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• 2024

본 논문에서는 전기차 시장의 성장 및 수요 증가로 인한 충전 인프라 부족에 대한 문제를 해소하기 위한 방안으로, 센서를 활용한 각 자리별 빈 주차 자리 확인 기능과 전기차 충전 자리의 남은 대기 시간에 대한 정보를 실시간 모니터링 할 수 있는 시스템을 구현하였다. 기존의 LED 표시등의 정보를 웹사이트를 통해 시각적으로 전달하며, 실시간으로 주차 여유 공간과 전기차 충전 자리의 대기 시간을 확인할 수 있게 하였다. 더불어 발레 파킹 서비스와의 융합을 통해 충전 완료 후 차량 이동의 불편함 및 인프라 운영의 효율을 늘리는 방안을 제안해본다.