젊은 성인에서 선천성 십이지장격막에 의한 십이지장 폐쇄

이환효(Hwan-Hyo Lee),김형국(Hyung-Guk Kim),윤영욱(Young-Yuk Yoon) 대한외과학회 2003 Annals of Surgical Treatment and Research(ASRT) Vol.64 No.4

유주비장의 염전에 의한 비장경색 1예

이환효(Hwan Hyo Lee) 대한외과학회 1999 Annals of Surgical Treatment and Research Vol.57 No.6

정수처리에서 pH 저감에 의한 응집효율향상에 관한 연구

이환,이철효,정창규,이윤진,Lee, Hwan,Lee, Cheol-Hyo,Jung, Chang-Gue,Lee, Yoon-Jin 한국환경보건학회 2003 한국환경보건학회지 Vol.29 No.2

This paper reports on a pilot scale comparison of PACS coagulation with and without pH preadjustment. The pH of the water was adjusted with carbon dioxide and sulfuric acid. Process performance was assessed on the basis of total organic carbon(TOC), UV absorbance, turbidity and disinfection by-product(DBP) precursors. Coagulation pH appeared to be a determining factor for maximum NOM removal. The optimum coagulation pH in order to decrease TOC and turbidity were pH 7. Preadjustment of pH 7 increased TOC removal to as much as 43, 47 percent with sulfuric acid and carbon dioxide. Moreover, coagulation at pH 7 caused a reduction in UV$_{254}$, THMFP and HAAFP compared to the baseline coagulation. For preadjustment of pH 7 with carbon dioxide, the percentage of TOC, UV$_{254}$, THMFP and HAAFP shows the reduction rate of 3.8, 0.5, 4.8, 9.4% comparing to the coagulation rendition using sulfuric acid. Acid addition to depress pH during coagulation decrease Langelier Saturation Index(LSI), potentially causing increase corrosion in water distribution systems. LSI for carbon dioxide and sulfuric acid at pH 6 was -2.3, -3.3. Therefore, carbon dioxide was more effective at controlling corrosion than sulfuric acid.

TNT 오염토의 염기성 가수분해 효율 향상을 위한 최적 운전인자 도출

이환,최재헌,이철효,김주엽,Lee, Hwan,Choi, Jae-Heon,Lee, Cheol-Hyo,Kim, Ju-Yup 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.6

Nitro-aromatic Compounds (NACs) of explosives are structurally non-degradable materials that have an adverse effect to humans and ecosystems in case of emissions in natural due to the strong toxicity. In this study, batch test in the laboratory-scale has been conducted to find some process parameters of alkaline hydrolysis by considering the characteristics of NACs which are unstable in a base status and field application evaluation have been performed on the batch test results. Based on the experimental results of both laboratory and pilot-scale test, the optimum conditions of parameters for the alkaline hydrolysis of soils contaminated with explosives were pH 12.5, above the solid-liquid ratio 1 : 3, above the room temperature and 30 minute reaction time. In these four process parameters, the most important influencing factor was pH, and the condition of above pH 12.0 was necessary for high contaminated soils (more than 60 mg/kg). In the case of above pH 12.5, the efficiency of alkaline hydrolysis was very high regardless of the concentrations of contaminated soils. At pH 11.5, the removal efficiency of TNT was increased from 76.5% to 97.5% when the temperature in reactor was elevated from room temperature to 80℃. This result shows that it is possible to operate the alkaline hydrolysis at even pH 11.5 due to increased reaction rate depending on temperature adjustment. The results found in above experiments will be able to be used in alkaline hydrolysis for process improvement considering the economy.

소간세포암에서 혈관내피세포성장인자의 발현과 재발과의 상관관계

이지현(Ji-Hyun Lee),이광웅(Kwang-Woong Lee),김성주(Sung Ju Kim),최성호(Seong Ho Choi),허진석(Jin Seok Heo),김용일(Yong Il Kim),이환효(Hwan Hyo Lee),박진완(Jin Wan Park),박철근(Cheol Keun Park),권기영(Ghee Young Kwon),조재원(Jae Won J 대한외과학회 2005 Annals of Surgical Treatment and Research(ASRT) Vol.68 No.1

복강내결핵의 임상적 고찰

홍성만(Sung Man Hong),김대황(Dae Hwang Kim),이환효(Hwan Hyo Lee),공효(Hyo Gong),우제홍(Ze Hong Woo) 대한소화기학회 1994 대한소화기학회지 Vol.26 No.6

N/A We analysed 48 patients with intraabdominal tuberculosis and treated at the Department of General Surgery, National Medical Center, from January 1985 to December. We evaluated the efficiency of diagnostic modalities for intraabdominal tuberculosis and provided the guideline for therapeutic trials. The ratio of male to female was 1: 1.1. The peak inciodence were the second(27.1%) and third decades(22.9%). The frequent symptoms were abdominal pain (75%), nausea and vom- iting(33.3%), and abdominal mass(25.0%). The duration of symptom was within 1 month (77.1%) mostly. Twenty two cases (45.8%) were associated with pulmonary tuberculosis,' other 3 cases extrapulmonary tuberculosis. In the AFB smears of ascites, 2 cases(13.3%) showed positive reaction. The correct preoperative diagnosis was possible in 23 cases(64.9% ). Thirty six cases(75.0%) needed operation '. 20 cases(55.5%) received emergency operation and the other elective operations. The major operative procedures were right hemicolectomy (22.8%) and segmental rescetion of small bowels(22.8%). The frequent operative findings were tuberculous mesenteric lymphadenopathy(52.8%), adhesion(38.9%), intestinal perfora- tion(25.0%), ascites(22.2%). The postoperative complications including wound infections, pneumonia and enterocutaneous fistula were occurred in 11 cases(31.6%). Other 12 cases were not operated and took antituberculous medications, and improved symptomatically. We suggests that intraabdominal tuberculosis should be differentiated from various surgical abdo- men with vague symptoms or signs, especially in young patient. We recommend antituberculous medications in suspicious case. In complicated cases, emergency operations such as intestinal resection or enterostomy should be performed.(Korean J Gastroenterol 1994; 26: 1021-1028)

사용종료 매립지의 가스 활용 방안평가

이철효(Cheo-hyo Lee),전연호(Yeon-ho Jeon),이채영(Chae-young Lee),김경(Kyung Kim),이환(Hwan Lee),이남훈(Nam-hooll Lee) 유기성자원학회 2000 유기물자원화 Vol.8 No.2

LFG 활용 기능성을 평가하기 위하여 매립 가스 발생량 모벨을 적용한 결과 Scholl Canyon 모벨이 가장 효과적인 것으로 나타났다 종료 매립지의 매립가스 활용을 위하여 자연 발생량 이상의 매립가스의 과도한 추출은 외부 공기의 유입으로 인하여 메탄 농도의 감소 및 산소 농도의 증가를 야기하여 매 립 가스의 활용을 방해하는 것으로 나타났다. 따라서,매 립 가스 추출을 통한 안정화 방법은 비효과적이며,LFG 추출은 모벨에 의해서 산정된 LFG 자연발생량 이하로 추출하는 것 이 바람직하다.8 년 이 경과한 시점에서 종료 매 립지의 매 립가스를 활용하는 방안은 자연발생량이 급격히 감소하여 매립종료 직후보다 비경제적이나 자연 발생량 이하로 소규모 이용시에는 타당성이 있는 것으로 나타났다 Landtìll gas (LFG) ucilization in old landfill was estimated using LFG models. The reslJtS showed that Scholl Canyon model best described rhe LFG generation. LFG was extracted more rhan rhe amoullt of natural production which caused air inflow from outside that resulted in dilution of merhane concentration and increase of ox:ygen concentration. It was negative for the LFG lltilization. Therefore, to llse LFG, rhe plan of stabilization by LFG extraction showd be ineffective. The llse of LFG will have no problem if LFG is extracted Iess rhan rhe amount of natLtral prodllction which was estimared based on mode1ing. At 8 years elapsed from landtìll, now, rhe amollnt of natura1 landfill gas production was decreased sharply. The plan for llsing LFG from old landtìll is feasible if LFG is used for the less than rhe amoullt of natura1 production as a small sca1e even rhough for rhe aspect of efficiency, it was less economic than luSe of LFG just after closing landfJling and it was helpful for stabilization of landfJI by LFG extractJon.

배치형과 연속흐름형에 의한 토양 중 RDX의 아임계 분해특성 비교연구

최재헌,이환,이철효,김주엽,박정훈,조영태,Choi, Jae-Heon,Lee, Hwan,Lee, Cheol-Hyo,Kim, Ju-Yup,Park, Jeong-Hun,Jo, Young-Tae 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.6

The purpose of this study is to compare the degradation characteristics by subcritical water of RDX contaminated soil using batch mode and dynamic mode devices. First, upon application of RDX contaminated soil, RDX treatment efficiency was increased with increasing the temperature in both modes. At 150℃, the treatment efficiency was 99.9%. RDX degradation efficiency got higher with lower ratio of solid to liquid. However, the treatment efficiency in the dynamic mode tended to be decreased at a certain ratio of solid to liquid or lower. The treatment efficiency was increased when it took longer time for the reactions in both modes. As the results of analysis on concentration of treated water after subcritical water degradation, the RDX recovery rate of dynamic and batch modes at 150℃ was 10.5% and 1.5%, respectively. However, both modes showed very similar recovery rates at 175℃ or higher. RDX degradation products were analyzed in treated water after it was treated with subcritical water. According to the results, RDX degradation mechanism was mostly oxidation reaction and reduction reaction was partially involved. Therefore, it suggested that most of RDX in soil was degraded by oxidation of subcritical water upon extraction. According to this result, it was found that both batch and dynamic modes were very effectively applied in the treatment of explosive contaminated soil.

공기주입 방식을 이용한 매립모형조내 폐기물 안정화

김경,박준석,이환,이철효,김정대,Kim, Kyung,Park, Joon-Seok,Lee, Hwan,Lee, Cheol-Hyo,Kim, Joung-Dae 한국환경보건학회 2005 한국환경보건학회지 Vol.31 No.1

This study was conducted to evaluate air injection mode on stabilization of solid waste in lysimeter. For three lysimeters, one was maintained under anaerobic condition as control, and air was injected into two lysimeters in continuous mode (atmospheric pressure) and intermittent mode (high pressure of 2 bar). Distilled water was sprayed over solid waste in 1.4 l/$m^3$(solid waste)/day, supposing rainfall intensity of 1,200 mm/yr and 30% infiltration. Oxygen in landfill gas was not detected in control lysimeter during operational days. After 30 day-aeration, oxygen concentrations of continuous and intermittent modes were maintained in 14% and 6%, respectively. $COD_{Cr}$ removal efficiencies of continuous and intermittent modes were about 70% and 50%, and BOD5 removal efficiencies were about 80% and 20%, respectively. In view of oxygen supply, and $COD_{Cr}$ and $BOD_5$ removal, continuous air injection mode of atmospheric pressure was more effective than intermittent mode of 2 bar. Settling degree of solid waste in case of two air injection modes was 3 times higher than that of anaerobic condition as control. Considering the above results, it was thought that air injection (especially continuous atmospheric pressure) could improve degradation of solid waste and induce preliminary stabilization in landfill site.

아임계수 분해를 이용한 난분해성 물질로 오염된 토양의 정화 연구

최재헌(Jae Heon Choi),이환(Hwan Lee),이철효(Cheol Hyo Lee),김주엽(Ju Yup Kim),오석영(Seok Young Oh) 大韓環境工學會 2015 대한환경공학회지 Vol.37 No.2

본 연구에서는 대표적 난분해성 유기화합물인 PCBs (Polychlorinated Biphenyls) 및 기타 난분해성 물질 오염토양을 정화하기 위하여 고온고압의 물을 이용하였다. 먼저, PCBs 오염토 적용시 반응온도에 따른 영향에서는 아임계수 조건에서 온도가 증가함에 따라 처리효율이 선형적으로 증가하였고 반응시간의 증가에 따라서도 처리효율은 증가함을 보였다. 처리입 경별 실험에서는 미세토의 경우가 처리효율이 약간 낮았다. 아임계수와 영가철에 의한 PCBs 분해 기작을 예측하기 위해 Ion chromatography 및 GC-MS 분석을 한 결과 탈염화 반응산물이 생성되었으며 헤드스페이스 실험결과 PCBs분해기작은 대부분 산화이며, 일부만이 탈염화에 의한 것임을 확인하였다. TPH, BTEX, TCE/PCE, 클로르피리포스 등의 난분해성 물질 오염토처 리를 위해 300℃ 아임계수 조건을 적용한 결과 모두 90% 이상의 처리효율을 나타냈으며, 처리효율과 반응부산물 등의 검토 를 통해 PCBs 오염토 외에 다른 난분해성 물질 오염토 처리분야에도 적용가능함을 확인하였다. This study examined remediation of soil contaminated with polychlorinated biphenyls (PCBs) and other persistent organic pollutants by using subcritical water. Our results showed that removal efficiency of PCBs from soil and treatment temperature were linearly proportional under subcritical conditions. The removal efficiency as increased as reacting period increased. PCBs contaminating fine particles in soil were less effectively removed than those in entire contaminated soil. Reaction of the zero-valent iron and PCBs under subcritical condition produced dechlorinated product, where most of the PCBs were oxidised while little remained as dechlorinated. Other organic pollutants, such as TPH, BTEX, TCE/PCE, and chlorpyrifos, were removed by more than 90% at 300℃. Considering removal efficiency and identification of by-products, we suggest that subcritical water treatment may be effectively applied to soils contaminated with various persistent organic pollutants.