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Seo, C.K.,Choi, B. Korean Society of Industrial and Engineering Chemi 2015 Journal of industrial and engineering chemistry Vol.25 No.-
The purpose of this study is to investigate the physicochemical characteristics according to hydrothermal aging, sulfur poisoning and HCs co-existence of Fe-zeolite (1), (2) and V<SUB>2</SUB>O<SUB>5</SUB>-WO<SUB>3</SUB>-TiO<SUB>2</SUB> SCR which are appropriate for diesel engines. Fe-zeolite (1) is a zeolite with low Fe content (~1wt.%) while Fe-zeolite (2) is a zeolite with a high Fe content (1.8wt.%). The BET specific surface area of Fe-zeolite (2) was smaller than that of Fe-zeolite (1) but its NH<SUB>3</SUB> storage capacity was larger than Fe-zeolite (1) because Fe-zeolite (2) has a large amount of Al content that can absorb NH<SUB>3</SUB>. In the case of Fe-zeolite (2), thermal durability was strong, When mildly set in hydrothermal aging for 12 and 24h at 600 and 700<SUP>o</SUP>C respectively, the NOx conversion rate was higher than the Fresh catalyst above 350<SUP>o</SUP>C. The active site of the catalyst, which is an Fe site, was damaged during the hydrothermal aging process, resulting in a decline in low-temperature performance. However, at higher temperatures, the NH<SUB>3</SUB> oxidation was largely hindered by the damage to the Fe site. The highest degree of coking arose for Fe-zeolite (1). On the other hand, V<SUB>2</SUB>O<SUB>5</SUB>-WO<SUB>3</SUB>-TiO<SUB>2</SUB> SCR, exhibited high durability against HCs, and experienced less coke deposition. Of the three catalysts V<SUB>2</SUB>O<SUB>3</SUB>-WO<SUB>3</SUB>-TiO<SUB>2</SUB> SCR suffered the least sulfur poisoning (0.007g/L). Due to the effects of Bronsted acid site, its resistance to sulfur poisoning is sufficient for reduction catalysts for exhaust gases from ship engines.
The optimal volume of a combined system of LNT and SCR catalysts
Seo, C.K.,Kim, H.,Choi, B.,Lim, M.T. Korean Society of Industrial and Engineering Chemi 2011 Journal of industrial and engineering chemistry Vol.17 No.3
This paper aims to find the optimal volumes of the LNT (Lean NOx Trap) and SCR (Selective Catalytic Reduction) catalysts for higher de-NOx performance and suppression of N<SUB>2</SUB>O and NH<SUB>3</SUB> in a combined system of LNT+SCR. The basic characteristics of the LNT catalyst were identified first at various space velocities (SV), and then the effects of the variation in volume of the combined system were investigated. The NOx conversion, NH<SUB>3</SUB> production, and N<SUB>2</SUB>O emissions were evaluated of four differently sized LNT-SCR systems. Considering all together the NOx conversion, cost of the precious metal, NH<SUB>3</SUB> slippage, and N<SUB>2</SUB>O generation, the optimal volume ratio of LNT and SCR catalysts was found to be 1:1 for the LNT-SCR system.
김석현,남윤수,유능수,박무열,김태형,박해균 강원대학교 산업기술연구소 2006 産業技術硏究 Vol.26 No.A
A vibration monitoring is performed on a 1kW class stand alone wind turbine(W/T). When a W/T model is developed, general performance under various wind condition should be verified to introduce the product in the market. Especially, vibration characteristics within operating speed range are very important in the aspect of structural stability as well as generator's electrical efficiency. This paper examines the vibration performance of a home made 1kW W/T. Various data of the W/T model are acquired in real time using a remote vibration monitoring system installed in Daekwanryung test site. Vibration stability of the W/T structure is diagnosed based upon the data and the result is used to estimate the applicability of the W/T model.
김석현,김태형,김윤호,한영호 강원대학교 산업기술연구소 2006 産業技術硏究 Vol.26 No.A
The Chun-cheon Citizen's Bell was cast in memory of hosting the 2010 world leasure conference and a striking ceremony was held at the city hall on December 31, 2005. In this study, vibration and sound of the bell are measured and the property of the magnificent sound of the bell is scientifically investigated. Frequency components making the sound are identified and how the frequency components decrease with time is observed using waterfall plot(3-dimensional frequency spectrum). Beat characteristics of the hum(1st frequency) and the fundamental(2nd frequency)are examined by experiment. Directivity of the sound radiation of the bell is examined by measuring the vibration and sound in several directions. Duration of the vibration and the sound is estimated using damping ratio.
자연기흉 환자에서 폐쇄성 흉강삽관술후 경피적 전기신경 자극법을 이용한 통증감소효과 연구
이석열,이길노 순천향의학연구소 1999 Journal of Soonchunhyang Medical Science Vol.5 No.1
Pain control methods after closed thoracostomy in spontaneous pneumothorax patients were used by analgesics, physical therapy, intercostal nerve block but effectiveness have not been proved due to various side effect and uncertified therapic effect. In this study, transcutaneous electrical nerve stimulation(TENS) was applied to pain control and it's effectiveness was observed from immediate closed thoracostomy to post-operative 3 days. Forty-five closed thoracostomy patients was classified into 3 groups, which are TENS group(n=15), placebo group(n=15) and control group(n=15). The TENS group was treated with TENS unit, the placebo group was treated using the unit without electrical connection, and the control group received analgesic alone. Same analgesic(demerol) intramuscular injection was used in three groups as pain control. Among the 3 groups, there were no statistical significant difference in age, body weight, operation time, lidocaine amounts and vital signs. However pain intensity by visual analogue scale and analgesic requirements were decreased in TENS group as compared with others(P<0.05). Finally, pain control by TENS after closed thoracostomy was proved to effective pain control method therefore analgesic requirements was decreased.
金石三 경북대학교 공과대학 1982 工大硏究誌 Vol.11 No.-
Friction and wear tests of dry sliding were performed on alloyed tool steel (STS 3) to investigate tribometric characteristics and surface characteristics. The results obtained are as follows: 1) The coefficient of friction decreases with the normal load and nearly independent on sliding velocity (μ=0.3 - 0.7) 2) The average hardness of wear surface increases with the normal pressure, but it stays constant above the normal pressure of 0.45 ㎏/㎟ 3) In a given wear regime, the abraded wear volume of STS3 increases linearly with normal load.