內科病棟에서 본 有熱疾患의 現況 : 俗稱 不明熱에 대한 檢討

尹吉子,全鍾暉,楊愛琳 대한감염학회 1975 감염 Vol.7 No.1

Clinical observation was made in 317 patients with febrile diseases was admitted to the department of internal medicine of St. Mary's hospital from July 1973 to June 1975. 1) Of 98 patients with clinical impression of Typhoid fever, 78 patients was confirmed bacteriologically (71 cases) or serologically (7cases) as Typhoid fever. Of 219 patients without typical clinical symptoms of Typhoid fever, 44 cases was proved to be Typhoid fever. 2) Incidence of positive blood culture was high in patients with typical classical manifestations of Typhoid fever. (severe cases!) 3) In view of the fact that incidence of serological or bacterological positivity was low in patients with Typhoid fever who was previously treated with antibiotics. It is suggested that significant portion of the patients with FUO particularly the patient who improved symptomatically on antibiotics application, may turn out to be the Typhoid fever. Bone marrow-and Liver-biopsies could be supplementary diagnostic procedures in the cases of bacterioseronegative suspicious Typhoid fever.

Friction Behavior of High Velocity Oxygen Fuel (HVOF) Thermal Spray Coating Layer of Nano WC-Co Powder

T.Y. Cho,J.H. Yoon,K.S. Kim,W. Fang,Y.K. Joo,K.O. Song,S.J. Youn,S.Y. Hwang,H.G. Chun 한국표면공학회 2007 한국표면공학회지 Vol.40 No.4

High Velocity Oxygen Fuel (HVOF) thermal spray coating of nano size WC-Co powder (nWC-Co) has been studied as one of the most promising candidate for the possible replacement of the traditional hard plating in some area which causes environmental and health problems. nWC-Co powder was coated on Inconel 718 substrates by HVOF technique. The optimal coating process obtained from the best surface properties such as hardness and porosity is the process of oxygen flow rate (FR) 38 FMR, hydrogen FR 57 FMR and feed rate 35 g/min at spray distance 6 inch for both surface temperature 25℃ and 500℃. In coating process a small portion of hard WC decomposes to less hard W₂C, Wand C at the temperature higher than its decomposition temperature 1,250°C resulting in hardness decrease and porosity increase. Friction coefficient increases with increasing coating surface temperature from 0.55-0.64 at 25℃ to 0.65-0.76 at 500℃ due to the increase of adhesion between coating and counter sliding surface. Hardness of nWC-Co is higher or comparable to those of other hard coatings, such as A1₂O₃, Cr, Cr₂O₃ and HVOF Tribaloy 400 (T400). This shows that nWC-Co is recommendable for durability improvement coating on machine components such as high speed spindle.

Reuse of Reclaimed Water for Irrigation on Paddy Rice Culture and Its Effect

( Chun G. Yoon ),( Jong-hwa Ham ),( Ji-hong Jeon ) 한국농공학회 2002 韓國農工學會誌 : 전원과 자원 Vol.44 No.7

The effect of reclaimed water irrigation on paddy rice culture was evaluated by pilot study at the experimental field of Konkuk University in Seoul, Korea. The sewage was treated by constructed wetland system, and its effluent was used as irrigation water for four treatments and one control plots with three replications. Irrigation of reclaimed water onto paddy rice cultures did not adversely affect the growth and yield of rice. Instead, experimental rice plots of reclaimed water irrigation displayed about 10 to 50% more yield on average than controls. This implies that reclaimed water irrigation might be beneficial rather than harmful to rice culture as long as the sewage is treated adequately and used properly. The amount of irrigation water had little effect on experimental rice cultures, but its strength was important. The strength of treated sewage was not a limiting factor in this study, and no lodging was observed even with a relatively high nitrogen concentration (up to 160mg/L). In general the paddy soil was not affected by reclaimed water irrigation. However, there was an indication that continuous irrigation with high strength of reclaimed water might cause salt accumulation in the soil. Supplemental use of reclaimed water with existing sources of irrigation water is recommended rather than irrigation with a single source of reclaimed water. Overall, the results demonstrated that reclaimed water could be reused as a supplemental source of irrigation water for paddy rice culture without causing adverse effects as long as it is properly managed. For full-scale application, further investigation should be done on environmental risks, tolerable water quality, and fraction of supplemental irrigation.

자연정화방법에 의한 오수처리와 농업적 재이용 타당성 검토

윤춘경 ( Chun G. Yoon ),정광욱 ( Kwang Wook Jung ),함종화 ( Jong Hwa Ham ),전지홍 ( Ji Hong Jeon ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.6

A pilot study was performed to examine the feasibility of the pond system for further polishing of treatment wetland effluent to agricultural reuse of reclaimed water. The constructed wetland and pond system was installed in Konkuk University and the effluent from septic tank of school building was used as an influent to the wetland system. The effluent of the wetland was used as an influent to pond systems. The influent concentrations of total coliform(TC), fecal coliform (FC), and E. coli were about 10⁵MPN/100 ml, and they were reduced to less than 10,000 MPN/100 ml on average after wetland treatments, showing over 95 % removal. And they were further reduced to less than 1,000 MPN/100 ml in average, showing over 85∼93 % removal after pond treatment. Turbidity and SS were improved effectively on average and their pond effluent concentration was about 4.5 NTU and 9.8 mg/L in average, respectively Average BOD⁵ concentrations were also reduced substantially to 9.3 mg/L with about 83 % removal rate after wetland and pond treatment systems. Nutrients removal was relatively low and removal rate for T-N and T-P was less than 43 and 44%, respectively after wetland and pond treatment. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, pond system was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water. This paper describes a preliminary result Iron pilot study and further investigations are recommended on the optimum design parameters before full scale application.

용수재이용을 위한 하수처리 유출수의 UV 소독 후 광회복 조사

윤춘경 ( Chun G. Yoon ),정광욱 ( Kwang Wook Jung ),함종화 ( Jong Hwa Ham ),전지홍 ( Ji Hong Jeon ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.3

Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration was monitored with time after UV-disinfection. Under the darkness, their initial concentration of 10∼30 MPN/100 mL increased to the level of 100 MPN/100 mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time. Under the fluorescent lamp, photoreactivation was more apparent that their concentration increased up to 1,000 MPN/100 mL which might significantly impair the water uses specially in reuse of reclaimed wastewater. However, their concentration further decreased down to below 2 MPN/100 mL under the solar radiation primarily due to additional disinfection by solar radiation rather than photoreactivation. Samples not disinfected by UV-disinfection also demonstrated substantial decrease of their concentration under solar radiation from about 5,000 MPN/100 mL to less than 30 MPN/100 mL in 24 hours. But direct reuse of effluent without disinfection is not recommended because natural decay by solar radiation may take time and be affected by climatic conditions. The result suggests that photoreactivation of pathogenic microorganisms may not be concerned in agricultural reuse of reclaimed wastewater because solar radiation may provide further disinfection after UV-disinfection.

농업적 용수재이용을 위한 간헐분사 완속모래여과 하수재처리 효율 평가

윤춘경 ( Chun G. Yoon ),정광욱 ( Kwang Wook Jung ),함종화 ( Jong Hwa Ham ),황하선 ( Ha Sun Hwang ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.5

A pilot study was performed to examine the feasibility of intermittent slow sand filtration for agricultural reuse of reclaimed water. The effluent of biofilter for 16-unit apartment was used as influent to the slow sand filtration system at 0.6 ㎥/day loading rate using 15 seconds spray in every 10 minutes on the about 1㎡ surface area and 0.5 m depth. The influent concentrations of total coliform (TC), fecal coliform (FC) and E. coli were in the range of 10.000 MPN/100 mL, and they were reduced to less than 1,000 MPN/100 mL after filtration with average of 320, 270, and 154 MPN/100 mL, respectively, showing over 95 % removal. Turbidity and SS were improved effectively and their average concentration was reduced to 0.8 NTU and 1.7 mg/L, respectively, and removal rate was about 50 %. Average BOD and COD concentrations were also reduced substantially to 2.6 and 25.8 mg/L with about 55 and 21 % removal rate, respectively. Nutrients removal was relatively low and removal rate for T-N and T-P was low however, remaining nutrients might be beneficial and less concerned in case of agricultural reuse. The concentration of biofilter effluent used in this experiment was in the range of secondary treatment effluent but slightly stronger than the one from existing wastewater treatment plants (WWTPs). Therefore, intermittent slow sand filtration might be also applicable to the effluent from WWTPs as long as its agricultural reuse is available. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, the intermittent slow sand filtration was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water. This paper is a preliminary result from pilot study and further investigations are recommended on the optimum design parameters before full scale application.

용수재이용을 위한 하수처리 유출수의 UV 소독 효율 연구

윤춘경 ( Chun G. Yoon ),정광욱 ( Kwang Wook Jung ),함종화 ( Jong Hwa Ham ),전지홍 ( Ji Hong Jeon ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.2

The feasibility study of UV-disinfection system was performed for disinfection of effluent from wastewater treatment plant. Three low-pressure UV lamps of 17, 25, and 41 W were examined with various flow rates. Low-pressure UV lamps of 17W were examined with various turbidity, DOM (dissolved organic matter), and SS (suspended solid). The pilot plant was a flow-through type UV-disinfection system, and the range of exposure time varied from 5 to 40 seconds, turbidity from 0 to 40 NTU, DOM from 0 to 30 mg/L, and SS from 10 to 40 mg/L. The 41W lamp demonstrated complete disinfection showing no survival ratio in all the experimental conditions, and generally 17W and 25W lamps also showed high removal ratio over 97%. For the same UV dose (UV intensity times exposure time), high intensity-short exposure conditions showed better disinfection efficiency than low intensity-long exposure conditions. While the effects of turbidity and DOM were not apparent, the effects of SS was significant on the disinfection efficiency which indicates that SS control before UV-disinfection appears to be necessary to increase removal efficiency. Considering characteristics of effluent from existing wastewater treatment plants, cost-effectiveness, stable performance, and minimum maintenance, the flow-through type UV-disinfection system with high intensity and low-pressure lamps was thought to be a competitive disinfection system for wastewater reclamation.

담수심과 오수처리수 관개가 벼재배에 미치는 영향

윤춘경 ( Chun G. Yoon ),황하선 ( Ha Sun Hwang ),정광욱 ( Kwang Wook Jung ),전지홍 ( Ji Hong Jeon ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.4

Pilot study was conducted to examine the effects of ponded-water depth and reclaimed wastewater irrigation on paddy rice culture. For the ponded-water depth effect, three treatments of shallow, traditional, and deep water depths were applied, and each treatment was triplicated. The irrigation water for the treatment pots was an effluent from constructed wetland system for sewage treatment, while the control pot was irrigated with tap water kept traditional ponded-water depth. Irrigation water quantity varied with ponded-water depth as expected and drainage water quantity also varied similarly, which implies that shallow irrigation might save irrigation water and also reduce environmental impacts on downstream water quality. Rice growth and production were not significantly affected by ponded-water depth within the experimental condition, instead there was an indication of increased production in shallow and deep ponded-water depths compared to the traditional practice. Raising drainage outlet to the adequate height in paddy dike might be beneficial to save water resources within the paddy field. There was no adverse effect observed in reclaimed wastewater irrigation on the rice production, and mean yield was even greater than the control pots with tap water irrigation although statistically not significant. Water-saving irrigation by shallow ponded-water depth, raising the outlet height in diked rice paddy fields, minimizing forced surface drainage by well-planned irrigation, and reclaimed wastewater irrigation are suggested to save water and protect water quality. However, deviation from traditional farming practices might affect rice growth in long term, and therefore, further investigations are recommended before full scale application.

맨틀형 축열조의 열전달 성능 및 특성에 관한 실험적 연구

강용혁(Y.H.Kang),곽희열(H.Y.Kwak),윤환기(H.G.Yoon),유창균(C.G.Yoo),윤현식(H.S.Yoon),천원기(W.G.Chun) 한국태양에너지학회 2001 한국태양에너지학회 논문집 Vol.21 No.1

Lipid-mediated delivery of brain-specific angiogenesis inhibitor 1 gene reduces corneal neovascularization in an in vivo rabbit model

Yoon, K C,Ahn, K Y,Lee, J H,Chun, B J,Park, S W,Seo, M S,Park, Y-G,Kim, K K Nature Publishing Group 2005 Gene therapy Vol.12 No.7

Corneal neovascularization, which occurs in many pathologic states of the cornea, reduces the visual acuity. Recently, we found that the extracellular region of brain-specific angiogenesis inhibitor 1 (BAI1-ECR) has antiproliferative activity through functional blocking of α<SUB>v</SUB>β<SUB>5</SUB> integrin in endothelial cells. In this study, we investigated the effects of lipid-mediated subconjunctival injection of the BAI1-ECR gene on corneal angiogenesis induced by epithelial debridement by heptanol in the rabbit. When a pEGFP-BAI1-ECR plasmid was given subconjunctivally 1 week after epithelial debridement, green fluorescence was detected in the corneal stroma with expression persisting for 7 days. To test the effect of BAI1-ECR on neovascularization, rabbits were injected with the BAI1-ECR gene or empty vector two or three times at 1-week intervals beginning 1 week after debridement. When measured with biomicroscopy at 1 or 2 weeks after two weekly injections, BAI1-delivered eyes had significantly less neovascularized corneal area than vector-injected ones in both time periods. Similar microscopic results were obtained after three weekly injections of BAI1-ECR. In quantitative histological examination, the BAI1-receiving eyes showed significantly less neovascular area and number of vessels than vector-injected ones. Also, after two weekly injections, BAI1-delivered eyes had decreased neovascularized corneal area equivalent to that of anti-VEGF antibody-injected ones. These results indicate that BAI1-ECR gene delivery effectively reduces experimental corneal neovascularization and suggest that the BAI1-ECR protein can be used as an angiogenesis suppressor in the eye.Gene Therapy (2005) 12, 617–624. doi:10.1038/sj.gt.3302442 Published online 10 February 2005