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조류와 유기화합물의 동시제거를 위한 흡착 - DAF 복합공정
이재욱,곽동희,최승필,정흥조 대한상하수도학회 2004 상하수도학회지 Vol.18 No.2
Dissolved air flotation (DAF) is an effective solid/liquid separation process for low density floc particles such as algal, color-alum and clay-alum flocs produced from low turbidity water. The removal of taste and odorcausing organics (2-mthylisoboneol and geosmin) originating from algae in drinking water is a local and worldwide concern. Although DAF has been effectively applied for the removal of suspended solid, its application for the treatment of dissolved organic carbon is very limited. In this study, a new hybrid system consisting of adsorption and DAF processes was introduced for the simultaneous removal of algae and taste and odorcausing organics. Powdered activated carbon (PAC) was used as an adsorbent. In this proposed system, the major concern of eliminating the spent PAC from the system was also addressed. It was found that zeta potential of algae and PAC was increased with coagulant dosage, and the removal efficiency in DAF was also enhanced up to 90-95% under the given experimental conditions. Based on this study, the hybrid process was found to be a promising technology for the simultaneous removal of algae and dissolved organic pollutants.
CO₂ 자동차 에어컨 시스템의 최적 고압 설정 알고리즘 개발에 관한 연구
이준경(Jun Kyoung Lee),이동혁(Dong Hyuk Lee),이헌균(Heon Kyun Lee),원종필(Jong Phil Won),최규정(Kyu Jung Choi),주필호(Phil Ho Ju),이원석(Won Suk Lee),최동기(Dong Ki Choi) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper deals with the development of optimum high pressure control algorithm for a transcritical CO₂ mobile air-conditioning system to achieve the maximum COP. The experiments were performed under idle and driving operating conditions. The experimental results demonstrated that the COP of the transcritical CO₂ system is a strong function of the gas cooling pressure. In other words, the COP was increased and then decreased with increase of the high pressure. Therefore the value of high pressure which has maximum COP could be selected. Furthermore, the strong(linear) relation between the optimum high pressure and the gas cooler outlet temperature was revealed, which suggests a simple controller of only one parameter for the transcritical CO₂ cycle.
운전조건 변화가 CO₂ 자동차 에어컨 시스템의 냉방성능에 미치는 영향에 대한 실험적 연구
이준경(Jun Kyoung Lee),이동혁(Dong Hyuk Lee),이헌균(Heon Kyun Lee),원종필(Jong Phil Won),최규정(Kyu Jung Choi),주필호(Phil Ho Ju),이원석(Won Suk Lee),최동기(Dong Ki Choi) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper deals with the research for the effects of the operating parameters that could be used for a transcritical CO₂ mobile air-conditioning system on the cooling performance. It presents experimental results for the performance characteristics of a CO₂ mobile air conditioning system with various operating conditions such as different gas cooler inlet pressures and frontal air velocities/temperatures passing through the evaporator and the gas cooler. Experimental results show that the cooling capacity was more than 5㎾ and coefficient of performance (COP) was more than 2.1, also. Therefore, we checked that the mobile air-conditioning system using CO₂ has good cooling performance compared to that using HFC-134a.
Choi, Joon-Phil,Shin, Gi-Hun,Brochu, Mathieu,Kim, Yong-Jin,Yang, Sang-Sun,Kim, Kyung-Tae,Yang, Dong-Yeol,Lee, Chang-Woo,Yu, Ji-Hun JAPAN INSTITUTE OF METALS 2016 MATERIALS TRANSACTIONS Vol.57 No.11
<P>Selective laser melting (SLM) is an attractive manufacturing technique for the production of metal parts with complex geometries and high performance. This manufacturing process is characterized by highly localized laser energy inputs during short interaction times which significantly affect the densification process. In this present work, experimental investigation of fabricating 316L stainless steel parts by SLM process was conducted to determine the effect of different laser energy densities on the densification behavior and resultant microstructural development. It was found that using a low laser energy density below 50 J/mm(3) produced an instable melt pool that resulted in the formation of unmelted particles, pores, cracks, and balling in the as-built parts with low densification. In contrast, the as-built parts at a high energy density above 200 J/mm(3) showed irregular scan tracks with a number of pores and metal balls that decreased part density. The optimal laser energy density range was accordingly determined to be 58-200 J/mm(3) by eliminating obvious SLM defects, which led to near full densification. The SLM samples fabricated using optimal parameters allowed observation of a microhardness of 280 Hv, ultimate strength of 570 MPa, and yield strength of 530 MPa that were higher than those of the as-cast and wrought 316L stainless steel.</P>
최형철,김종호,하정희,이광윤,김원준,곽동석,김성희,송필현,여지현 영남대학교 의과대학 1999 Yeungnam University Journal of Medicine Vol.16 No.2
Background: Anticholinesterase drug inhibits acetylcholinesterase(AChE), induce accumulation of acetylcholine(ACh) near cholinergic receptors and cholinergic stimulation. This experiment was performed to study the effects of anticholinesterase drugs on gastric motility and the effect of ethanol on anticholinesterase drug-induced motility change. Materials and Methods: After excision of stomach, 2×10mm circular muscle strips were made, which were then fixed to the isolated muscle chamber. An isometric tension transducer was used to measure the contraction change of the gastric smooth muscle strips after drug addition. Results: Fenthion, an irreversible anticholinesterase drug, increased ACh induced contraction of gastric smooth muscle strips and PAM, a cholinesterase activator, antagonized this action. Physostigmine, a reversible anticholinesterase drug, also increased the ACh induced contraction. The gastric motility was decreased by PAM. Ethanol, which is known to induce smooth muscle relaxation, inhibited the increase of contraction by fenthion. Conclusion: These results indicate that irreversible and reversible anticholinesterase drugs increase gastric motility and antagonized by cholinesterase activating drugs. And when exposed to both ethanol and anticholinesterase drug, gastric motility was decreased by the smooth muscle relaxation effect by ethanol.