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        • KCI등재

          CFD 모델링을 통한 연료전지용 디젤의 흡착탈황 반응기 디자인

          상구(Sang Gu Kwon),유준(Jay Liu),임도진(Do Jin Im) 한국청정기술학회 2015 청정기술 Vol.21 No.4

          현재 국내에서 수소 관련 연구에 대한 관심이 매우 크나 수소원으로 사용하는 디젤 등 연료 내 존재하는 황 화합물을 제거하는 흡착 시스템 개발 관련 연구는 매우 미흡한 실정이다. 따라서 본 연구에서는 수치해석을 통해 연료전지용 디젤 흡착 탈황 반응기에 대한 기초 디자인 연구를 수행하였다. 유량에 따른 반응기 내부의 유동 변화와 출구에서의 황 화합물의 농도를 반응기의 지름 및 길이를 변화시켜가며 해석하여, 출구에서의 황 화합물의 기준 농도 (1 ppm)를 맞추기 위한 탈황 촉매의 성능을 예측하였으며 반응기의 길이 증가가 지름 증가보다 효율적임을 확인하였다. 또한, 충전된 탈황 촉매의 투과율에 따른 내부 유동 및 농도 변화를 살펴보았다. 본 연구 결과는 선박 연료전지용 디젤의 흡착 탈황 반응기 디자인 기초 자료로 활용될 것으로 기대된다. 또한, 연료전지뿐 아니라 일반적으로 정유사에서 생산되는 디젤유의 황 함유량을 감소시키는 저황 시스템 디자인에 활용할 수 있으며 이러한 의미에서 석유화학 산업의 청정화 기술 확보에 이바지할 것으로 기대된다. Recently, there are increasing numbers of study regarding hydrogen fuels but researches on desulfurization of diesel are rare. In this study, we performed diesel desulfurization reactor design by computation fluid dynamics simulation. By analyzing the change in flow and sulfur concentration at the outlet according to the changes in flow rate, reactor length, and reactor diameter, we have found the minimum catalyst performance for the given flow rate condition and the relation between the reactor performance and the reactor size and shape. We also studied the effects of permeability of the packed bed on the flow and sulfur concentration distribution. The present work can be utilized to design a diesel desulfurization reactor for a fuel cell used in ships. Furthermore, the present work also can be used to design low sulfur diesel supply in oil refineries and therefore contribute to the development of clean petrochemical technology.

        • KCI등재후보

          Atomic Force Microscopy를 이용한 그래핀의 미세구조 및 나노역학 특성 분석

          상구,박정영 한국세라믹학회 2013 세라미스트 Vol.16 No.3

          '스콜라' 이용 시 소속기관이 구독 중이 아닌 경우, 오후 4시부터 익일 오전 7시까지 원문보기가 가능합니다.

        • H.264/AVC 컨텐츠의 공간해상도 트랜스코딩을 위한 고속 모드 결정 방법

          상구,정봉수,전병우,Kwon Sang-Gu,Jung Bong-Soo,Jeon Byeung-Woo 대한전자공학회 2006 電子工學會論文誌-SP (Signal processing) Vol.43 No.3

          As wireless network technology has advanced, demands for multimedia contents through mobile environment have tendered to upward. Since network situation is changing every moment and types of user terminals are diverse, it is difficult for a content provider to consider network situation and type of user terminal to provide multimedia contents. As one solution, transcoding techniques have been proposed, but those have much complexity. In this paper, in order to reduce computational complexity, we propose a fast mode decision using input modes, motion vectors, and residual energies which are obtained from input bitstream for 2:1 down-scaling spatial transcoding application. The proposed method reduces processing time in mode decision by restricting possible mode types based on input information. Experimental results show that the proposed method achieves about 2.66 times improvement in encoding time compared to the normal encoding process while the PSNR is degraded by about 0.04dB, and bit-rate is increased by 1.6%. 무선 네트워크 기술이 발전함에 따라, 모바일 환경을 통한 멀티미디어 컨텐츠 공급이 증가하고 있는 추세이지만, 공급자가 시시각각 변화하는 네트워크 상황과 다양한 사용자의 단말기 종류를 모두 고려하여 적당한 컨텐츠를 공급하는 것은 매우 어렵다. 이러한 문제를 해결하기 위해 트랜스코딩 기술이 제안되었지만 계산 복잡도가 크다. 본 논문에서는 다양한 트랜스코딩 기술 중 하나인 공간해상도 트랜스코딩 기술에서 2:1 화면 축소를 대상으로 H.264에서 매크로블록의 모드 결정 과정 중에 필연적으로 발생하는 계산 복잡도를 줄이기 위해 입력 비트스트림에서 얻은 매크로블록의 모드, 움직임 벡터, 그리고 차-영상 에너지 정보를 이용한 고속 모드 결정 방법을 제안한다. 제안한 고속 모드 결정 방법은 입력 정보들을 비교하여 재-부호화할 매크로블록의 가능한 모드 종류를 제한하여, 모드 결정 과정에서 소모되는 시간을 단축시키는 방법이다. 실험 결과는 영상에 따라 약간의 차이는 있으나 제안한 방법이 일반 부호화 과정에 비해 평균적으로 PSNR은 약 0.04dB 손실이 발생하고 비트율은 약 1.6% 증가하나, 부호화 속도에서는 약 2.66배 빨라짐을 보여준다.

        • 兒童期 美術 指導에 關한 硏究

          權相玖 대구산업정보대학 1990 논문집 Vol.4 No.-

          The activity of the children's picture is a way to draw out the thinkings in their internal world. In the development of the children's picture, every stage has its own characteristics, as in the physical growth and mental development of human beings. The survey on the children's expressing way of drawing and the observation on their development of drawing were presented depending on their age, which enabled us to make the correct assessment about their pictures and the true understanding about them. This study was done comparatively on age, specific character, composition, side, color, and shape according to the children's growing developmental stage. The results have been drawn as follows; 1) The children's pictures were for the most part composed of lines resulting from the children's activities of body. However, these lines played an important role as activities of expression as children were getting older. 2) Most children expressed the shape by simple lines instead of the complicated lines. However, they could express in the concrete and free the shape in detail as they are growing in the body, as well as the intellect, and the sociality. 3) The development for observation was associated with the development of eyesight as children were getting older. 4) On the whole, Korean children showed earlier developmental stage of thinking and expressing the western countries children. I wish that this study can help children understand in terms of the development of their pictures and at the same time will be useful for the children's education of fine art.

        • KCI등재후보
        • KCI등재후보

          MIEX®를 이용한 수처리 효능 평가

          상구,손희종,노재순,최동훈,배석문,기원,신판세,김원경 한국수처리기술연구회 2003 한국수처리학회지 Vol.11 No.3

          The performance of a novel magnetic ion exchange resin supplied by its manufacturer Orica Australia(M1EX® DOC Resin) in terms of the removal of dissolved organic carbon(DOC). reduction in disinfection by-product formation potential, and effects on the removal of turbidity has been investigated. Two water samples(Maeri and prepared raw waters) were first treated with MIEX® at various doses and contact times, followed by conventional coagulation. Measurements of DOC. UV-254. THMFP, HAAFP and turbidity were made at each stage. In addition, readings of anions, including Br- were also obtained. For comparison, conventional coagulation/sedimentation alone was carried out using fixed levels of coagulant of 60㎎/L for Maeri water, and 100 ㎎/l for prepared water respectively. The UV-254 and DOC removals by MIEX® treatment were shown to be superior to cuagulation, ie better by 11-40% and 20-26% for Maeri and prepared raw water respectively. Further coagulation of the 10 mL/L MIEX® treated waters to control turbidity increased the DOC removal by -16%. As MIEX® dose and contact time increased, the additional DOC removal by coagulation showed corresponding decreases. The DOC removal efficiencies by MIEX® treatment alone were 71% and 82% with Maeri and prepared raw waters respectively. while the corresponding figures achieved by coagulation alone were 48% and 49% respectively. The combination of MIEX® and coagulation(main1y to achieve treatment standard for turbidity) in series yielded DOC removal efficiencies of 83% and 88% for the two waters. The reduction in THMFP by MIEX® treatment was better than that achieved by coagulation by 20-49%. More significantly, MIEX® treatment delivered a reduction of HAAFP which was 50% better than that delivered by coagulation. However, the combination of MIEX® and coagulation, when compared with MIEX® treatment alone, showed only marginal improvements in THMFP and HAAFP. indicating that as a pre-treatment method, MIEX® was particularly effective in removing DBP precursors. MIEX® treatment significantly reduced the dose of coagulant which would be needed for turbidity control. In order to reduce the turbidity from 18(Maeri water) and 27 NTU(prepared raw water) to ( 2 NTU, MIEX® pre-treated water samples only required coagulant doses which were up to 80% less than those involved when coagulation alone was used. However. after MIEX® pre-treatment, low alkalinity waters(1ess than 20 ㎎/L) only showed a slight decrease in turbidity. Most anions in water decreased with MIEX® dose and contact time with Br- showing a reduction of up to 70% while Cl- showing a slight increase due to the effect of resin regeneration. This research showed that for Maeri water(5 ㎎/L DOC and 30 NTU), the pre-treatment with MIEX® dose of 10-16 mL/L and a contact time of 30 minutes yielded optimum results for DOC and DBP control. Coagulant dosage for turbidity control in this case decreased by as much as 20-30 ㎎/L(80%).

        • 위성 구조체의 FOV 간섭에 의한 S 대역 안테나의 방사 특성 영향성 분석

          임원규,기호,김중표,이선익,상구,원영진,문홍열,이상곤 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.4

          이 논문은 위성 구조체가 S 대역 안테나의 방사 방향에 위치할 경우, S 대역 안테나의 방사 특성변화를 주로 다루었다. S 대역 안테나는 반구면 방사 특성을 가지므로, 특정 구조체가 반구상에 위치할 경우 방사 특성에 대한 고려는 매우 중요하다. 위성 구조체중 탑재체용 안테나는 우수한 지향성을 나타내기 위해, S 대역과 비교해 상대적으로 매우 큰 안테나를 사용한다. 위성 설계에 따라, 구조적 간섭 가능성은 충분하며 이 논문에서는 이에 대한 가정으로 분석을 수행하였다. In this paper, we discussed S band antenna radiation characteristics having the structural blockage. Most S band antennas for TC and TM have hemi-spherical radiation characteristics. So, it is very important to consider the radiation characteristics in case some structures are located at the area. Especially, antenna for payload data transmitting channel have large size to show the high gain and high possibility to block the S band antenna field of view. According to satellite design, the structural interference could be occurred and this paper performed the analysis starting from the assumption.

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