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반탄화를 통한 고형 바이오 연료로서 대나무 칩의 연료 특성 확인
김선엽 ( Seonyeop Kim ),김하은 ( Haeun Kim ),남서연 ( Seoyeon Nam ),박선용 ( Sunyong Park ),김석준 ( Seokjun Kim ),오광철 ( Kwangcheol Oh ),조라훈 ( Lahoon Cho ),전영광 ( Youngkwang Jeon ),김대현 ( Daehyun Kim ) 한국농업기계학회 2023 한국농업기계학회 학술발표논문집 Vol.28 No.2
지구온난화로 인해 이상기후 발생이 증가하고 있어 환경오염에 대한 우려가 높아지고 있다. 신재생에너지 에너지 의무화제도로 인해 목재펠릿에 수요가 급증했다. 하지만 국내 우드펠릿 자급률은 15.9%에 불과하다. 산림청은 대나무를 제조 원료로 포함하도록 목재펠릿 품질 기준을 개정한다고 발표했다. 하지만 대나무의 발열량은 화석연료 대비 낮다. 따라서 본 연구는 반탄화 공정을 통해 활용도가 낮은 대나무의 연료 품질을 향상시킨다. 경상남도 합천군의 업체에서 구입한 대나무칩을 230℃에서 310℃까지 다양한 온도에서 1시간 동안 반탄화 하였다. 반탄화 된 시료로 질량수율을 측정하였을 때, 32.37%에서 76.74% 범위였으며 발열량은 19.50MJ/kg~28.68MJ/kg으로 다양했다. 또한 원소 분석결과, 반탄화 공정 온도가 높을수록 탄소의 비율은 43.93%-74.14%로 증가하고 수소와 산소의 비율은 각각 46.87-22.35%, 8.06-5.33%로 낮아졌다. 반탄화를 위한 최적 조건의 온도는 270℃인 것으로 나타났다. 결론적으로 반탄화 공정을 거친 대나무는 고형연료로서 이용가능성이 높다고 판단된다.
도로변 초미세먼지의 실시간 질량농도 및 부피농도 측정을 이용한 시간별 밀도 분석-광흡수 eBC에 대한 OPS 보정 중심
김은영(Eunyoung Kim),서석준(Seokjun Seo),김선문(Sunmoon Kim),정성운(Sungwoon Jung),이용민(Yongmin Lee),오세호(Sea-Ho Oh),박규태(Gyutae Park),김경훈(Kyunghoon Kim),김정화(Jounghwa Kim),홍유덕(Youdeog Hong),이태형(Taehyoung Lee),배민석(Mi 한국대기환경학회 2018 한국대기환경학회지 Vol.34 No.6
Kim, Hojoong,Hong, Seokjun,Jin, Yinhua,Lim, Dong Hyun,Kim, Jun-yong,Hwang, Hasub,Kim, Taesung The Electrochemical Society 2017 ECS journal of solid state science and technology Vol.6 No.8
<P>The formation of a ring-shaped residue after the chemical mechanical polishing (CMP) process of a copper (Cu) interconnect was investigated. The chemical composition of the residue was analyzed and found to be copper oxide (CuO). In the present study, the mechanism of CuO formation was investigated using interdisciplinary methods. First, the wafer surface was analyzed by electrical charge mapping and chemical composition analysis. These analyses revealed that the organic residue had not been removed in the region where the ring shaped CuO residue formed. Then, with the support of the analysis data, a hypothesis on residue formation was proposed. This hypothesis includes the nozzle configuration of the cleaning tool used in CMP. Investigations by experimental observation, as well as a simulation of chemical fluid motion, were conducted. It was shown that, owing to the configuration of the cleaning tool, there exists a specific region where the concentration of cleaning chemicals is too low for removing organic residue. Then, cross-contamination occurs without chemical fluid lubrication; in other words, there is direct solid-solid contact between the wafer and cleaning brush. Finally, the organic contamination on the wafer surface forms an electrical circuit, which results in the formation of CuO residue. (C) 2017 The Electrochemical Society.All rights reserved.</P>
Augmented reality-based remote coaching for fast-paced physical task
Kim, Youngsun,Hong, Seokjun,Kim, Gerard Jounghyun Springer UK 2018 Virtual Reality Vol.22 No.1
<P>One popular application of augmented reality (AR) is the real-time guidance and training in which the AR user receives useful information by a remote expert. For relatively fast-paced tasks, presentation of such guidance in a way that the recipient can make immediate recognition and quick understanding can be an especially challenging problem. In this paper, we present an AR-based tele-coaching system applied to the game of tennis, called the AR coach, and explore for interface design guidelines through a user study. We have evaluated the player's performance for instruction understanding when the coaching instruction was presented in four different modalities: (1) Visual-visual only, (2) Sound-aural only/mono, (3) 3D Sound-aural only/3D and (4) Multimodal-both visual and aural/mono. Results from the experiment suggested that, among the three, the visual-only augmentation was the most effective and least distracting for the given pace of information transfer (e.g., under every 3 s). We attribute such a result to the characteristic of the visual modality to encode and present a lot of information at once and the human's limited capability in handling and fusing multimodal information at a relatively fast rate.</P>
Kim, Hojoong,Hong, Seokjun,Shin, Cheolmin,Jin, Yinhua,Lim, Dong Hyun,Kim, Jun-yong,Hwang, Hasub,Kim, Taesung Elsevier 2017 Wear: An international journal on the science and Vol.392 No.-
<P>The surface roughness of a chemical mechanical polishing (CMP) pad provides microscopic asperities where the actual polishing takes place. Thus, the roughness should be maintained in a proper regimen to obtain stable CMP process quality. A conditioner is a key consumable in the CMP process because it maintains the roughness of the CMP pad surface against surface glazing or flattening during polishing. Because the conditioner mechanically breaks the pad surface to maintain the roughness, previous research has expressed its ability index in terms of the pad wear rate (PWR). In the present study, we investigate the reason for PWR change of CMP pads having vigorously changing moduli with respect to temperature changes during the mass production. The pad property changed steeply in the process temperature range from 60 to 80 degrees C. The tensile strength is a key property change that leads to sudden PWR drop. We found that the shape and configuration of the diamond tip are the major parameters affecting the ability to maintain surface roughness of the pads. Thus, we suggested a proper conditioner design for tungsten (W) CMP based on the experimental data to sustain the process quality and increase the consumable lifetime. As a result, the peak surface roughness has improved from 29.4 mu m to 32.6 mu m and the consumable lifetime was also increased.</P>