An Experimental Study on the Performance of Air/Water Direct Contact Air Conditioning System

Yoo, Seong-Yeon,Kwon, Hwa-Kil The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.6

Direct contact air conditioning systems, in which heat and mass are transferred directly between air and water droplets, have many advantages over conventional indirect contact systems. The purpose of this research is to investigate the cooling and heating performances of direct contact air conditioning system for various inlet parameters such as air velocity, air temperature, water flow rate and water temperature. The experimental apparatus comprises a wind tunnel, water spray system, scrubber, demister, heater, refrigerator, flow and temperature controller, and data acquisition system. The inlet and outlet conditions of air and water are measured when the air contacts directly with water droplets as a counter flow in the spray section of the wind tunnel, and the heat and mass transfer rates between air and water are calculated. The droplet size of the water sprays is also measured using a Malvern Particle Analyzer. In the cooling conditions, the outlet air temperature and humidity ratio decrease as the water flow rate increases and as the water temperature, air velocity and temperature decrease. On the contrary, the outlet air temperature and humidity ratio increase in the heating conditions as the water flow rate and temperature increase and as the air velocity decreases.

Molecular Characterization of Pseudomonas aeruginosa Isolates Resistant to All Antimicrobial Agents, but Susceptible to Colistin, in Daegu, Korea

Yoo Chul Lee,Byung Jun Ahn,Jong Sook Jin,Jung Uk Kim,Sang Hwa Lee,Do Young Song,Won Kil Lee,이제철 한국미생물학회 2007 The journal of microbiology Vol.45 No.4

Multi-drug resistant Pseudomonas aeruginosa has been implicated in a variety of serious therapeutic problems in clinical environments. Among the 968 P. aeruginosa isolates obtained from two hospitals in Daegu, Korea, we acquired 17 isolates that were resistant to all available tested antimicrobial agents, with the exception of colistin (colistin-only sensitive). We characterized the antimicrobial susceptibilities, metallo-β-lactamases, and epidemiological relatedness among the colistin-only sensitive P. aeruginosa isolates. All colistin-only sensitive isolates were positive in the modified Hodge test and imipenem-EDTA synergy test, thereby indicating the production of metallo-β-lactamases. 11 isolates from the secondary hospital and six isolates from the tertiary teaching hospital harbored blaVIM-2 and blaIMP-1, respectively. The pulsed-field gel electrophoretic analysis of the SpeI-digested DNA from P. aeruginosa isolates indicated that two different clones of colistin-only sensitive P. aeruginosa originated from each hospital, and had spread within the hospital environment. Overall, colistin-only sensitive P. aeruginosa was detected in Korea for the first time, but no pan-drug resistant bacteria were identified. Nationwide surveillance is required in order to monitor the emergence of colistin-only sensitive or pan-drug resistant bacteria.

목표농도조절주입 ( Target Controlled Infusion ) 을 이용한 Propofol 마취유도

길호영,양정화,유홍성,김태견,이성익,이승준,윤영준,박영주 대한정맥마취학회 1999 정맥마취 Vol.3 No.2

서론: 목표농도 조절주입은 약물의 정주방법을 단순하고 향상된 조절 방법으루 투여할 수 있는 새로운 약물투여 방법이다. 주입된 약물의 효과는 작용처의 농도에 의해 결정되는 이는 혈중농도와 밀접한 관련이 있다. 본 연구는 TCI를 이요한 propofol 마취유도를 위해 다양한 목표농도를 설정하고 이에 따른 마취유도 여부를 용량-반응 연구를 통해 분석함으로서 한국인에서 midazolam으로 전처치 한 경우 propofol 마취유도 시 적절한 목표 농도를 설정하는 동시에 활력징후의 변화 및 부작용에 대해 관찰하였다. 방법: 계획수술이 예정된 미국마취과학회 신체분류 등급상 1, 2에 속하는 체중 45∼100㎏, 연령 18∼55세의 남녀환자 66명을 대상으로 하였으며 심, 신 간장 질환이 있는 경우는 대상에서 제외하였다. 마취전처치로 마취유도전 1시간에 glycopyrrolate 0.2 ㎎ 및 midazolam 0.07 ㎎/㎏을 근주한 후 마취유도 시 목표농도를 3, 4, 5, 6 ㎍/㎖로 하는 네 개의 군으로 나누어 각각 15∼18명씩 임의로 배정하였다. 마취유도의 성공 여부는 약물주입 시작부터 3분이내에 눈을 떠보라는 요구에도 반응이 없는 경우로 정하였고 약물 주입동안 1분 간격으로 혈압 및 맥박, 10초 이상 지속되는 무호흡의 여부를 관찰하고 동시에 약물주입으로 인한 통증의 정도를 관찰하였다. 또한 마취유도 성공 시 마취유도 시간, 컴퓨터 주입기 화면에 표시된 마취유도 용량, 측정용량, 각성농도를 1.2 ㎍/㎖로 하였을 때의 상황민감성감소기를 관찰하였다. 결과: 목표농도 3 ㎍/㎖로 설정된 경우 환자의 25, 4 ㎍/㎖시 5.8.8%, 5 ㎍/㎖시 77.8%, 6 ㎍/㎖시 100%에서 성공적인 마취유도를 보여 목표농도 증가와 강한 상관관계를 보였다(r^2=0.98). Propofol의 마취유도를 위한 효과농도에서 EC_50은 3.87 ㎍/㎖, EC_95은 5.71 ㎍/㎖을 나타내었다. 각 군의 마취유도시간은 139∼166초로 각 군간의 차이를 보이지 않았으며 혈압, 맥박, 말초산소포화도와 주입 시 통증의 정도, 무호흡의 빈도, 부작용의 관찰도 각 군간에 차이를 보이지 않았다. 결론: Midazolam 전처치한 한국 성인의 경우 TCI를 이용한 propofol 마취유도는 목표농도 5∼6 ㎍/㎖에서 대부분의 대상환자가 활력징후의 개선이나 부작용 감소 등의 장점을 보이면서 성공적인 마취유도를 보였다. Background: Target Controlled Infusion (TCI) is designed to achieve a predicted target blood concentration based on population pharmacokinetics and it provides the closest approximation for any individual patients. This study determined which target is appropriate for propofol induction using a TCI in korean adult patients premedicated with midazolam. Methods: Sixty six patients (ASA Ⅰ or Ⅱ, 18~55 years) premedicated with midazolam were allocated randomly to receive an infusion to achieve and maintain a target blood concentration or 3, 4, 5 and 6 ㎍/ml using a TCI. Induction time was measured as the interval from the start of the infusion to loss of verbal contact and induction within 3 min was considered as successful. Calculated concentration, induction dose, context sensitive decrement time, vital signs, pain score and side effects were checked and compared each other during induction period. Results: The success rate when the target was 3 ㎍/ml was 25%, 58.8% and 100% when targets were 4 ㎍/ml, 5 ㎍/ml and 6 ㎍/ml respectively. Effective Concentration (EC)50 for induction was 3.87 ㎍/ml and EC95 was 5.71 ㎍/ml. Calculated concentration, induction dose, context sensitive decrement time in 3, 4, 5 ㎍/ml group showed no differences among groups, but 6 ㎍/ml group showed statistically significant differences compared with other groups. Vital signs, pain score and side effects showed no differences among groups. Conclusions: Target concentration of 5 ㎍/ml would successfully induce anesthesia in the majority of patients premedicated with midazolam without major hemodynamic changes.

Propofol을 이용한 전신마취 시 67% 아산화질소에 상응하는 Fentanyl 의 등제통 농도

길호영,유홍성,안현희,이윤숙,이현화 대한마취과학회 2002 Korean Journal of Anesthesiology Vol.42 No.6

A Review on the Photochemical Oxidant Modeling as Applied to Air Quality Studies in Complex Terrain

Lee Hwa-Woon,Kim Yoo-Keun,Won Gyeong-Mee,Park Jong-Kil The Korean Environmental Sciences Society 1997 Environmental sciences Vol.1 No.1

The high oxidants, which occur the daily maximum concentrations in the afternoon, are transported into the other region via long range transport mechanisms or trapped within the shallow mixing boundary layer and then removed physically (deposition, transport by mountain wind, etc.) and chemically (reaction with local sources). Therefore, modeling formation of photochemical oxidants requires a complex description of both chemical and meteorological processes. In this study, as a part of air quality studies, we reviewed various aspects of photochemical modeling on the basis of currently available literature. The result of the review shows that the model is based on a set of coupled continuity equations describing advection, diffusion, transport, deposition, chemistry, emission. Also photochemical oxidant models require a large amount of input data concerned with all aspects of the ozone life cycle. First, emission inventories of hydrocarbon and nitrogen oxides, with appropriate spatial and temporal resolution. Second, chemical and photochemical data allowing the quantitative description of the formation of ozone and other photochemically-generated secondary pollutants. Third, dry deposition mechanisms particularly for ozone, PAN and hydrogen peroxide to account for their removal by absorption on the ground, crops, natural vegetation, man-made and water surfaces. Finally, meteorological data describing the transport of primary pollutants away from their sources and of secondary pollutants towards the sensitive receptors where environmental damage may occur. In order to improve our present study, shortcomings and limitation of existing models are pointed out and verification process through observation is emphasized.

A Study of Iteration Method for 2-Dimensional 2-Group Diffusion Problems

Jong Hwa Chang,Kil Yoo Kim,Chang Hyun Chung Korean Nuclear Society 1983 Nuclear Engineering and Technology Vol.15 No.1

본 논문에서는 Shanks의 수열 전환방법 중 $E_{k}$-전환을 연구하여 $E_1$-전환과 single extrapolation 방법과의 관계를 정립하고 나아가서 중성자 확산 방정식의 반복법에 $E_1$$^2$-전환을 적용하여 double extrapolation 방법을 유도하고 있으며, 이를 CITATION코드에서 적용해 보았다. 이 경우 double extrapolation은 기존의 single extrapolation 방법보다 효과적으로 외부 반복법을 가속시키고 있는데 단, double extrapolation 방법이 일어날 수 있는 조건을 만족시켜 double extrapolation이 일어나는 경우이다. 또 CITATION코드는 내부 반복법에서 'Equipose' 방법이라하여 내부 반복횟수를 1회만 하고 외부 반복법으로 넘어가는 방법이 가장 빠른 것으로 간주하고 program이 되어 있으나, 내부 반복법에서 에너지 군별로 반복횟수를 다르게 줄 경우, 예를 들면 속 중성자속과 열 중성자속을 계산하는 반복과정중 반복횟수를 각각 2번과 1번으로 줄 경우는 기존의 Equipose보다 매우 빠름을 알 수 있다. 단, 이 경우는 에너지 군이 2군일 경우 명확하게 보여주고 있다. It is shown that the Shanks sequence $E_{k}$-transformation and the conventional extrapolation method are theoretically related. The $E_1$$^2$-transformation method is then applied for the multigroup diffusion problems. The diffusion code, CITATION, is modified for this study and the computing time is compared for each iteration tactics. The Equipose method, in which only sing1e inner iteration for each energy group is carried for an outer iteration, has been known as the fastest iteration method. However, in the case of 3-group problems, the proposed method, in which the number of inner iteration for the fast and thermal group is 2 and 1 respectively, gives better convergency than the Equipose method by about 12%. The double extrapolation method results in faster computing time than the single extrapolation method without computing storage problem. It is, however, to note that this method is verified only for a two-group treatment.t.

지표면의 특성을 고려한 대기경계층내의 열수지 parameter 추정 : 열수지 parameter를 이용한 중규모 순환의 수치예측

이화운,김유근,박종길,이순환,원경미 한국환경과학회 1996 한국환경과학회지 Vol.5 No.6

An one dimensional atmosphere-canopy-soil interaction model is developed to estimate of the heat budget parameter in the atmospheric boundary layer. The canopy model is composed of the three balance equations of energy, temperature, moisture at ground surface and canopy layer with three independent variables of T_f(foliage temperature), T_g(ground temperature), and q_g(ground specific humidity). The model was verified by comparative study with OSUID(Oregon State University One Dimensional Model) proved in HAPEX-MOBILHY experiment. Also we applied this model in two dimensional land-sea breeze circulation. According to the results of this study, surface characteristics considering canopy acted importantly upon the simulation of meso-scale circulation. The factors which used in the numerical experiment are as follows ; the change for a sort of soll(sand and peat), the change for shielding factor, and the change for a kind of vegetation.

Molecular Characterization of Pseudomonas aeruginosa Isolates Resistant to All Antimicrobial Agents, but Susceptible to Colistin, in Daegu, Korea

Lee, Yoo-Chul,Ahn, Byung-Jun,Jin, Jong-Sook,Kim, Jung-Uk,Lee, Sang-Hwa,Song, Do-Young,Lee, Won-Kil,Lee, Je-Chul The Microbiological Society of Korea 2007 The journal of microbiology Vol.45 No.4

Multi-drug resistant Pseudomonas aeruginosa has been implicated in a variety of serious therapeutic problems in clinical environments. Among the 968 P. aeruginosa isolates obtained from two hospitals in Daegu, Korea, we acquired 17 isolates that were resistant to all available tested antimicrobial agents, with the exception of colistin (colistin-only sensitive). We characterized the antimicrobial susceptibilities, $metallo-{\beta}-lactamases$, and epidemiological relatedness among the colistin-only sensitive P. aeruginosa isolates. All colistin-only sensitive isolates were positive in the modified Hodge test and imipenem-EDTA synergy test, thereby indicating the production of $metallo-{\beta}-lactamases$. 11 isolates from the secondary hospital and six isolates from the tertiary teaching hospital harbored $bla_{VIM-2}$ and $bla_{IMP-1}$, respectively. The pulsed-field gel electrophoretic analysis of the SpeI-digested DNA from P. aeruginosa isolates indicated that two different clones of colistin-only sensitive P. aeruginosa originated from each hospital, and had spread within the hospital environment. Overall, colistin-only sensitive P. aeruginosa was detected in Korea for the first time, but no pan-drug resistant bacteria were identified. Nationwide surveillance is required in order to monitor the emergence of colistin-only sensitive or pan-drug resistant bacteria.

포괄적 전사인자 분석을 위한 Degenerate RT-PCR/SSCP : Tumor Necrosis Factor-α 처리한 3T3-L1 지방세포에 적용 예 Application in 3T3-L1 Adipocyte Treated with TNF-α

김유리 ( Yoo Lee Kim ),이상화 ( Sang Hwa Lee ),최영길 ( Young Kil Choi ),장서윤 ( Seo Yoon Chang ),김연수 ( Yun Soo Kim ),김수경 ( Soo Kyung Kim ),박석원 ( Seok Won Park ),박원근 ( Won Kun Park ),조용욱 ( Yong Wook Cho ),이상종 ( 대한당뇨병학회 2007 Diabetes and Metabolism Journal Vol.31 No.5

부산광역시에서 철도차량 배출원에 의한 오염물질 배출량 산정

이화운,김유근,김희만,박종길,장난심,이희령 한국환경과학회 2001 한국환경과학회지 Vol.10 No.6

A case of air pollution study of estimation of emission rate for source to railroad rolling stock and emissive character about is unusual. Recent emission rate of railroad rolling stock was estimated with emission factor of EPA in three region(Seoul, Incheon, and Gyeonggido). But this EPA factor could be incorrect because Korea and America have a different railroad environment in the variety of fuel and character of railroad rolling stock. In this study, emission rate of each line, car and region(district) with emission factor of Korean case(National Railroad Administration, 1997) was estimated. In Busan Metropolitan City, railroad rolling stocks were divided accoding to, each line, car and service. Particularly, the idle fuel rate omitted in the preceding study was included in calculation fuel rate. Total emission rate of Busan Metropolitan City was 887.41t/year. Each emission rates of Kyeongbu line, Donghaenambu line, Gaya line, Uam line, Bujeon line, and idle was 489.15t, 196.46t, 33.94t, 12.66t, 6.47t, and 148.72t, respectively.