• 한국환경복원기술학회지
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• 제5권6호
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• pp.24-29
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• 2002

Nitrate removal rate in three cattail wetland cells was investigated. They were a part of a pond-wetland system for stream water treatment demonstration. The system was composed of two ponds and six wetland cells. The acreage of each cell was approximately $150m^2$. The earth works for the system were finished from April 2000 to May 2000 and cattails were planted in the three cells in June 2000. Waters of Sinyang Stream flowing into Kohung Estuarine Lake were pumped into a primary pond, whose effluent was discharged into a secondary pond. The reservoir was formed by a tidal marsh reclamation project and located in southern coastal area of Korean Peninsula. Effluents from the secondary pond were funneled into the three cells. Volumes and water quality of inflow and outflow were analyzed from July 2000 through January 2001. Inflow and outflow averaged $20.2m^3/day$ and $19.8m^3/day$, respectively. Hydraulic retention time was about 1.6 days. Average influent and effluent nitrate concentration was $1.98mg/{\ell}$, $1.38mg/{\ell}$, respectively. Nitrate removal rate averaged $82.6mg\;m^{-2}\;day^{-1}$. Seasonal changes of nitrate retention rates were closely related to those of wetland cell temperatures. The average nitrate removal rate in the cells was a little lower, compared with that of $125.0mg\;m^{-2}\;day^{-1}$ for the wetlands operating in North America. This could be attributed to the initial stage of the cells and inclusion of three cold months into the seven-month study period. Root rhizosphere in wetland soils and litter-soil layers on cell bottoms could not developed. Increase of standing density of cattails within a few years will establish both root zones suitable for the nitrification of ammonia to nitrates and substrates beneficial to the denitrification of nitrates into nitrogen gases, which may lead to increase of the nitrate retention rate.

• 대한토목학회논문집
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• 제11권1호
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• pp.99-108
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• 1991

도시화에 의한 도시수문사상의 급격한 변화는 도시지역의 주요한 내배수 처리시설인 유수지의 새로운 운영조작기준을 요구하고 있다. 따라서 본 연구는 한강 홍수 특성을 고려한 서울시 지역의 내배수처리기법을 개발하기 위한 것으로서 설계강우양상의 변화에 따른 기존 유수지의 침수여부를 분석하고 한강의 계획홍수위에 대한 유수지의 수문안전도를 검토하였으며, 이를 통하여 유수지 운영조작기준을 새롭게 제시하였다. 순간강우강도법과 Huff의 4분위법에 의하여 설계강우양상이 결정되었으며, 유수지의 유입수문곡선은 ILLUDAS모형과 RRL법을 적용하여 얻어졌다. 기존의 유수지 배수펌프 운영조작기준은 유수지의 저류량과 펌프유출량이 선형적인 관계를 갖도록 되어 있으나 본 연구 결과 유입량의 증감여부에 따라 유수지의 저류량과 유입량을 조합한 Gauss함수형태의 배수펌프 운영조작기준이 유수지의 침수방지에 효과적인 것으로 나타났다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.1219-1223
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• 2005

This study was accomplished to confirm the possibility of supplying stream minimum flow from detention storage which was determined to reduce peak flows of flood within developing planned district. The results analyzed was summarized as follows; Firstly, Sin-gil district situated in Ansan city was selected, of which watershed area has $0.56km^2$. And detention storage was determined to $5,370m^3$ from analyzing flood volume by the SCS unit hydrograph method. Secondly, using Visual Basic ver 6.0, a detention storage water balance model was developed, in which simulation was based on conditioning storage inflow and outflow according to streamflow volume or rate state. And streamflow was simulated using the DAWAST model. Thirdly, detention operation scenarios were consisted of the combinations with inflow referencing streamflow of 5mm/day, 10mm/day and outflow referencing streamflow of 1mm/day, 2mm/day. The developed detention storage water balance model was operated to simulate daily water storages of detention sized on flood by scenarios. Stream minimum flows were able to be supplied during 209 days to 237 days per a year, total volume of stream minimum flows supplied for this period was analyzed to reach 27 to $55\% of yearly streamflow volume. If inflow criteria of streamflows to detention was considered to be established on a theoretical condition, it is expected to supply stream minimum flows of 20 to $30\% of yearly streamflow from stream to detention. Also to maximize function of supplying urban stream minimum flow from detention storages, sewage waters within developing planned district have to be treated and entered to detention inflow together with streamflows to enrich function of detention planned to reduce flood volumes.

• Journal of Chest Surgery
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• 제32권1호
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• pp.10-15
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• 1999

배경: 건삭보존 승모판 치환술이 승모판 폐쇄부전증에 있어서는 좌심실 기능의 개선 및 술후 합병증을 줄일 수 있다고 알려져 있으나 승모판 협착증에 있어서는 좌심실 유출로의 폐쇄나 기계판엽의 운동장애 없이 적당한 크기의 기계판막을 삽입할 수 없다는 점등으로 아직 논란의 대상이 되고 있다. 대상 및 방법: 본원에서는 5명의 승모판 협착증환자와 7명의 승모판 폐쇄부전증 환자를 대상으로, 융합된 교련의 절개, 두꺼워진 판첨을 얇게 박리하고, 전판첨을 전판륜으로부터 2 mm 정도에 절개를 가하고 전판첨 중앙부를 절제하여 판엽을 두 개의 분절로 분리하여 교련부에 재 부착함으로써 건삭 및 판첨을 판륜에 위치이동 하면서 승모판막 치환술을 시행하여 건삭 및 판륜의 연속성을 유지하였다. 결과: 술후 기계판엽의 운동장애나 판막주위누출, 좌심실 유출로의 폐쇄 등 합병증 및 수술 사망환자는 없었다. 결론: 결론적으로 건삭보존 승모판 치환술이 승모판 협착증에 있어서도 안전하고 효과적인 수술방법이라 할 수 있다

• 대한의용생체공학회:의공학회지
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• 제18권1호
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• pp.25-36
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• 1997

To regulate cardiac output of the Total Artificial Heart(TAH) physiologically, the hemodynamic information must be toed back to the controller. So far, our group has developed an automatic cardiac output control algorithm using the motor current waveform, It is, however difficult to detect the preload level such as a filling status of ventricular inflow and the variation of atrial pressures within normal physiologic range(0-15 mmHg) by analyzing the motor current which simultaneously reflects the afterload effect. On the other hin4 the interventricular volume pressure(IVP) which is not influenced by arterload but by preload is a good information source for the estimation of preload states. In order to find the relationship between preload and IVP waveform, we set up the artificial heart system on the Donovan type mock circulatory system and measured the IVP waveform, right and left atrial pressures, inflow and outflow waveforms and the signals represented the information of moving actuator's position. We shows the feasibility of estimating the hemodynamic changes of inflow by using IVP waveform. fife found that the negative peak value of IVP waveform is linearly related to atrial pressures. And we also found that we could use the time to reach the negative peak in IVP waveform, the time to open outflow valve, the area enclosed IVP waveform as unfu parameters to estimate blood filling volume of diastole ventricle. The suggested method has advantages of avoiding thrombogenesis, bacterial niche formation and increasing longterm reliability of sensor by avoiding direct contact to blood.

• 한국산학기술학회논문지
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• 제8권5호
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• pp.1192-1200
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• 2007

도시유역의 강우 유출은 대부분 불투수지역인 도시유역의 유출 특성상 빠른 도달시간을 갖는다. 일반적으로 도시유역에서의 강우 유출은 배수펌프장으로 집수되어 하천으로 배제된다. 그러나 설계강우를 초과하는 호우가 발생하였을 때에는 배수펌프장의 용량을 초과하여 전량 하천으로 배제하기가 어려우며 따라서, 도시유역에서의 내수침수위험성이 증가하게 된다. 현행의 배수펌프장에서의 펌프 운영 기준은 배수펌프장의 집수정 또는 유수지의 수위에 따라서 가동되도록 구성되어있다. 그러나 최근 빈번히 발생하는 국지적 집중호우는 배수펌프장의 설계용량을 초과하는 경우가 대부분이며 배수펌프장이 제어할 수 없는 강우 유출은 도시유역에서의 내수침수를 발생시킨다. 본 연구에서는 도시 지하차도에서의 실제 내수침수 사례에 대한 모의를 통하여 당시 침수 발생의 요인을 분석하고 펌프 운영에 대한 변화를 통하여 배수펌프장 강제배제시설에 대하여 평가하였다.

• Journal of Chest Surgery
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• 제23권3호
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• pp.438-451
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• 1990

Pneumatic total artificial heart[TAH] has been clinically applied for the purpose of permanent or temporary use followed by cardiac transplantation in the patients with end stage heart diseases. In spite of the good durability of the pneumatic TAH, thrombus formation, bleeding and infection resulted in death. The Tomasu heart, which is a type of pneumatic TAH, was used in this study. This model is a modified Jarvik heart and consists of atrial cuffs, outflow vascular grafts and thin-layer seamless diaphragm type of ventricles. Cardiac outputs of the left artificial heart were measured by Donovan`s mock circulation under variable conditions of driving parameters, and an experimental artificial heart implantation was performed in 4 calves to observe the changes of hemodynamic parameters in early postoperative period and hematologic and bio-chemical changes in a long-term survival case. In the mock circulation test, cardiac output of the heart was increased with the increase of the left atrial pressure and left driving pressure. Maximum cardiac output was obtained at the heart rate of 120 to 130/min and percent systole of 40 to 45Zo under the condition of a constant left driving pressure of 180mmHg and left atrial pressure of 10mmHg. During the first 24 hours of TAH pumping, driving pressure ranged from 178$\pm$5mmHg to 187$\pm$8mmHg for the left heart and from 58$\pm$6mmHg to 78$\pm$28mmHg for the right heart. The Mean arterial pressure significantly increased between 2 and 8 hours after the start of pumping. The survival time ranged from 27 hours to 46 days. The causes of death were respiratory failure in 2 cases, mechanical valve failure in one, and left ventricular outflow obstruction due to thrombus in a 46-day survival case. This study demonstrated that Tomasu artificial heart operated effectively during the first 24 hours of artificial heart pumping, but thrombus formation around the valve holding area was the main problem in long-term survival case.

• Journal of Chest Surgery
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• 제27권6호
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• pp.435-443
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• 1994

Surgical procedures to relieve congenital right ventricular outflow tract[RVOT] obstruction of heart were performed on 125 patients from September 1985 to August 1992. There were 65 males and 60 females. Ages ranged from 7 months to 33 years with a mean age of 8 years. All the patients were divided into three main groups[I, II, III] depending on the presence or absence of cyanosis and combined anomalies. The patient were classified into two groups; A and B according to the outcome after surgical repair. Group A included the patients who had a good postoperative outcome with or without mild complications such as wound disruption, or hydrothorax. Group B included the patients who had a poor outcome including hospital death and significant postoperative complications such as heart failure, low output syndrome, respiratory failure, hepatic failure and others. And the results were summarized as follows. 1. There were no significant differences in age, body surface area and aortic dimension among the group I, II, and III, but there were significant differences among groups in pulmonary arterial dimension, ACT[aortic cross clamping time], TBT [total bypass time], preoperative and postoperative ratio of systolic pressure of right and left ventricles [pre PRV/RV and post PRV/LV], and the size of Hegar dilator which passed through the RVOT postoperatively [p<0.05]. 2. In the group A and B, there were significant differences in pulmonary arterial dimension [group A:1.6$\pm$0.5 cm, group B:1.9$\pm$0.6 cm], ACT [group A:102.3$\pm$ 46.0 minute, group B:76.1$\pm$46.1 minute], TBT [group A:133.9$\pm$56.6 minute, group B:94.9$\pm$51.9 minute], pre PRV/LV [group A:1.06$\pm$0.24, group B:0.8$\pm$0.32], post PRV/LV [group A:0.58$\pm$0.18, group B:0.43$\pm$0.16].It has been concluded that postoperative prognosis of RVOT obstruction was influenced by pulmonary arterial dimension, ACT, TBT, severity of RVOT obstruction [pre PRV/LV] and post PRV/LV.

• 한국산학기술학회논문지
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• 제15권5호
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• pp.3231-3239
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• 2014

1970~1980년대의 급격한 경제개발과 도시의 발전 이후 현재에 들어 당시에 개발된 원도심지의 노후화와 기존기능이 빠르게 빠져나가는 도심공동화 현상이 발생하면서 근래에 도시재생이 도시계획 및 도시개발의 새로운 키워드로 등장하였다. 천안의 구도심인 명동지역(중앙동, 문성동)또한 공동화 현상이 급격하게 진행되면서 천안시에서는 재개발 및 활성화 사업을 진행하였지만 효과를 거두지 못하고 있다. 이에 본 연구에서는 이론적 고찰을 통해 도시재생 및 TOD개발 관련 사례를 분석해보고 명동지역의 현황분석을 통해 명동지역의 발전 및 공동화 이유와 기존 활성화 사업의 문제점을 분석하였다. 이를 바탕으로 명동지역의 새로운 활성화 계획을 제안하였다. 활성화 계획의 내용을 요약하면 다음과 같다. 1)명동지역의 경우 버스터미널과 천안역, 중앙시장까지 어우르는 도시흐름을 형성하는 하나의 결절점으로 고려되어야 하며, 2)민자역사유치, 지하상가와 연결된 쇼핑루트 개발, 통합 환승센터 및 이를 중심으로 한 마켓단지조성, 동남구청 부지의 문화센터 개발 및 예술공원 등의 개발이 서로 연계하여 이루어져야 한다.

• 한국화재소방학회논문지
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• 제32권6호
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• pp.7-14
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• 2018

본 연구에서는 방화막 및 자연배출구 면적이 공연장 무대 화재 시 연기 거동에 미치는 영향에 대해 Fire Dynamics Simulator (FDS)를 이용하여 전산시뮬레이션(Numerical simulation)을 수행하였다. 공연장의 무대 크기는 폭 31 m, 깊이 34 m, 높이 32 m로 설정하였고, 자연배출구 면적은 무대 바닥면적의 약 10%, 약 8%, 약 5%, 약 1%로 하였다. 방화막은 프로시니엄(Proscenium) 벽과 0.5 m 이격하여 설정하였다. 방화막과 자연배출구 면적은 객석으로의 연기유출, 자연배출구 및 프로시니엄 개구부를 통한 유입 및 유출 질량 유량에 지대한 영향을 미치는 것으로 관찰되었고, 동일한 자연배출구 면적 조건에서 방화막이 설치된 경우가 미설치된 경우에 비해 무대 내 압력이 더 낮은 것으로 나타났다.