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고분자 전해질 연료전지 가스확산층의 압축상태 관통기체투과율 측정
엄세훈,이용택 대한기계학회 2019 大韓機械學會論文集B Vol.43 No.2
The gas diffusion layer (GDL) is in charge of the diffusion of gases and the discharge of water in the proton exchange membrane fuel cell (PEMFC). The change in the through-plane gas permeability of a GDL was experimentally measured in a compressively deformed state. The channel part was designed similarly as the actual PEMFC, and thus the compression and gas flow take place at the same time because the compression is co-directional to the gas flow in measuring the through-plane gas permeability. Three channel widths were applied, and the permeability was measured while varying the compressive load. TGPH-120, which is frequently used in PEMFCs, was used, and the permeability was obtained according to the PTFE loading, which was added to improve the water repellency of the GDL. In this paper, through-plane permeability under actual compressive conditions is proposed, and the results can contribute to an improvement in the modeling accuracy of the transport phenomena in the GDL. 고분자전해질연료전지(PEFMC)의 구성부품 중에서 기체의 확산과 물의 배출을 담당하는 가스확산층(GDL)의 관통 기체투과율(through-plane gas permeability)의 변화를 압축변형 되는 조건에서 실험적으로 측정하였다. 관통투과율은 압축방향과 기체의 투과방향이 동일하기 때문에 압축과 동시에 기체의 흐름이 가능하도록 실제의 PEMFC의 채널부와 유사한 시편압축부를 도입하였다. 3가지의 채널폭을 적용하고 이를 이용하여 압축하중을 변화시키면서 압축변형되는 GDL을 통한 관통투과율을 측정하였다. PEMFC에서 대표적으로 사용되는 TGPH-120 GDL을 사용하였으며 GDL의 발수성을 향상시키기 위하여 첨가되는 PTFE에 따라서 변화되는 관통투과율도 제시되었다. 본 연구에서는 GDL의 실제 압축조건에서의 관통투과율을 제시하며 그 결과는 향후 GDL의 전달현상의 모델링의 정확성 향상에 기여할 수 있다.
대기압에서 고출력 파워의 H²L² 유도 결합 플라즈마 소스를 이용한 CO₂ 분해 및 CH₄ 건식 개질 기술
엄세훈(Saehoon Uhm),이윤성(Yunseong Lee),송호현(Hohyun Song) 한국진공학회 2018 진공 이야기 Vol.5 No.4
CO₂ dissociation and CH₄ dry reforming, by high power and Highly inductive antenna, Highly coupled with the plasma, Low antenna voltage, Low plasma loss( H²L²) inductively coupled plasma (ICP) torch at atmospheric pressure, have been studied. At a frequency of 400 kHz and power of 30 kW, the ICP torch source dissociates CO₂ gas directly, causing CH₄ dry reforming. The resulting product mix is composed mainly of syngas and C₂ hydrocarbons, such as C₂H6, C₂H₄, and C₂H₂. The results show conversion efficiencies for both CO₂ and CH₄ of 95%. At an input power of 22 kW, a CO₂ flow rate of 30 standard liters per minute (SLM), and a CH₄ flow rate of 36 SLM, the energy conversion efficiency is 60%. As input CH₄ flow rate increases, the selectivity of CO and H₂ decreases and the selectivity of C₂ hydrocarbons increases. In this condition, energy conversion efficiency increases. As a result, the high conversion efficiency of CO₂ and CH₄, the large amount of products, and the high selectivity of C₂ hydrocarbons can be seen as important factors for achieving higher energy conversion efficiency in the CH4 dry reforming process. The associated chemical reactions are simulated using CHEMKINPRO tool, and the results illustrate the tendency of CO₂ and CH₄ conversion efficiency to vary with variations in selected parameters, and syngas and C₂ hydrocarbons production trends achieved in the simulation agree with experimental results.
복강경하 대장절제술을 시행 받는 환자에서 라모세트론과 온단세트론외 술 후 오심 및 구토 예방 효과 비교
김효중;어전영;어근무;어정한;엄세훈;조광래;김명훈 인제대학교 2011 仁濟醫學 Vol.32 No.-
Objectives : We evaluated the efficacy of ramosetron and ondansetron for preventing postoperative nausea and vomiting (PONV) in laparoscopic colectomy. Methods and Materials : Eighty patients who received laparoscopic colectomy were randomly divided into two groups: R group (ramosetron 0.1mg PO) and O group (ondansetron 4mg twice IV). Injection or oral medication was administered before the induction of anesthesia in each group. Injection was administered at the end of surgery in O group. General anesthesia was induced using propofol and rocuronium, and maintained with sevoflurane, remifentanil and air (FiO2 0.5), We investigated the incidences of PONV in each group by the Rhodes index of nausea, vomiting and retching (RINVR) at postoperative 6 and 24 hours. Results : The incidence of PONV was not different between group at each time points after surgery (at postoperative 6 hours: 20% in group R, 17.5% in group 0, at postoperative 24 hours; 12.5% in group R, 7.5% in group 0). There was no difference in the severity of PONV, satisfaction, rescue drug usage. Conclusion : Prophylactic therapy with ramosetron is as effective as conventional prophylactic therapy with ondansetron for preventing PONV in general anesthesia for laparoscopic colectomy.
높은 균일도를 갖는 300mm 공정용 유도 결합 플라즈마 원 개발 연구
이원기,정진욱,엄세훈,이용관 한국물리학회 2005 새물리 Vol.51 No.2
An inductively coupled plasma (ICP) source driven at 13.56 MHz was developed. The ICP antenna consists of two floors, each floor having a 1-turn antenna that makes up an antenna node. The ICP were charact-erized by using a single Langmuir probe. The plasma density was found to be in the range of 10$^{11}$ $\sim$ 10$^{12}$ cm$^{-3}$ and radial uniformity was within $\pm 5 ~\%$, over a large 300 mm. The electron temperature was 2 $\sim$ 3 eV. The developed ICP source is expected to be suitable for 300 mm wafer etching and for deposition. 13.56MHz에 동작되는 유도 결합 플라즈마를 개발하였다. 안테나는 이층구조로 하나의 안테나의 마디 부분을 다른 안테나가 보완하도록 제작하였다. 단일 량뮤어 탐침으로 플라즈마 진단을 수행했으며 플라즈마 밀도는 10$^{11}$ $\sim$ 10$^{12}$ cm$^{-3}$ 이고 균일도는 300 mm 지름에서 약 $\pm 5 ~\%$ 이내였다. 전 자온도는 2 $\sim$ 3 eV 였다. 개발된 유도결합 플라즈마는 300 mm 에칭이나 증착 공정에 적합할 것으로 보인다.