• Journal of Chest Surgery
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• 제46권4호
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• pp.274-278
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• 2013

Background: Coronary involvement in Takayasu's arteritis is a rare but fatal disease. The aim of this study was to evaluate the early and mid-term results of Takayasu's arteritis patients who underwent coronary artery bypass grafting (CABG). Materials and Methods: Of 2,280 patients who underwent isolated CABG from January 1998 to June 2012, Takayasu's arteritis was identified in 5 patients. There were 3 female patients, and the mean age was $58{\pm}9$ years. Takayasu's arteritis was diagnosed during preoperative evaluation for coronary artery disease in 4 patients, and the initial manifestation was angina pectoris in 4 patients. All of the patients underwent anaortic off-pump CABG (OPCAB) using the in situ left or right internal thoracic arteries (ITA); 3 patients had severe stenosis of the proximal left subclavian artery and the in situ right ITA was used instead. Medical treatment for inflammatory arteritis during the perioperative and follow-up period was performed if indicated. Early, 1-year, and 5-year angiographic results and clinical outcomes were analyzed. Results: There was no surgical mortality, and all of the patients were discharged without complications on postoperative $8{\pm}2$ days. Early postoperative (postoperative $2{\pm}1$ days) angiography demonstrated a graft patency of 100% (12 of 12 distal anastomoses). One-year ($13{\pm}3$ months) angiography was performed in 4 patients, and all of the grafts were patent (100%, 9 of 9 distal anastomoses). Conclusion: By performing anaortic OPCAB in patients with Takayasu's arteritis, we were able to avoid complications associated with manipulating an atherosclerotic and severely calcified ascending aorta. The early and mid-term graft patency of OPCAB in Takayasu's arteritis was maintained when concomitant with medical treatment.

• Journal of Chest Surgery
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• 제54권5호
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• pp.377-382
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• 2021

Background: Subclavian vein (SV) catheterization is a method for the delivery of fluids, drugs, and blood products, venous blood sampling, and central vein pressure monitoring in cardiac surgery. Catheter occlusion is a serious complication of SV catheterization during cardiac surgery, especially after sternal retractor expansion. Methods: In this observational study, 303 patients who had successful right infraclavicular SV catheterization from September 2019 to April 2020 were enrolled to determine the incidence of catheter occlusion. After catheterization, the lumens of all catheters were checked for the ability to infuse and withdraw blood from the catheter before and after sternal retractor expansion. The patients' characteristics, cannulation approach, on-pump or off-pump technique, occlusion of the catheter and its lumens, and any associated complications were recorded. The data were analyzed using IBM SPSS ver. 22.0 (IBM Corp., Armonk, NY, USA). Results: Of the 303 patients studied, 205 were male (67.7%) and 98 were female (32.3%). Catheter occlusion occurred in 11 patients with on-pump cardiopulmonary bypass (CPB) (227 patients) and 4 patients with off-pump CPB (76 patients) (p=0.863). The incidence of catheter occlusion was 4.95% (15 of 303 patients) with no cases of simultaneous 3-lumen occlusion in a catheter. The most commonly occluded lumen was the distal lumen (57.92%). Simultaneous 2-lumen occlusion occurred in 4 patients. Catheter occlusion was found in 3 of 13 malpositioned catheters (23.07%). Conclusion: The current study showed that malpositioning of the catheter tip was a risk factor for catheter occlusion and that the distal lumen of a triple-lumen catheter was the most commonly occluded lumen.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.580-585
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• 2000

Recently TEIS model, Two-zone model aid Stanitz equations are often used for off-design performance prediction of centrifugal compressor and pump. The prediction results often agree well with experimental data. However these models and equations have some important variables which have a great influence on overall performance prediction me. But no systematic study about these variables has been performed. So, in this paper, a systematic study about these variables influence on overall performance prediction owe is peformed. Finally the meaning of the variables and the research to be undertaken are discussed.

• 드라이브 ㆍ 컨트롤
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• 제14권1호
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• pp.29-34
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• 2017

This study analyzed a life test method for a power take-off (PTO) gearbox. An engine transfers mechanical power (rotation and torque) to a hydraulic pump through a PTO Gearbox with one input shaft and three output shafts. PTO gear box durability under high loads over long time periods was tested using dynamometers. In order to reflect the rated operating conditions, power must be distributed to each output shaft, and experiments were conducted under various conditions to verify the characteristics of the distributed power. An accelerated life test was designed using speed and torque as acceleration factors. Also, efficiency tests were conducted under various load conditions. Also, a lubrication oil composition analysis was performed to analyze gearbox wear status.

• 설비공학논문집
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• 제8권1호
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• pp.76-87
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• 1996

Energy analysis for the hot water heating control system of apartment house complex is accomplished by computer simulation. Mathematical model of a boiler, pipe network and a unit-house is developed. The effects of heating control methods on the heating performance and energy consumption of the system are investigated. The heating control methods considered in this study are a continuous heating control, and on-off heating control and an intermittent heating control methods. For each control method, the effects of an outdoor temperature, indoor temperature sensing position and the capacities of the boilers and circulating pumps on the heating performance and energy consumption are obtained and "the best" control method is recommended.commended.

• 한국태양에너지학회 논문집
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• 제31권2호
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• pp.143-147
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• 2011

On-off differential controller is one of the very important component which has influence on the system performance of the solar hot water system. In this study, it was analysed the influence of "on-off" setting temperature on the system efficiency and the electrical consumption by circulation pump. This study was performed by computer simulation using TRNSYS program. The simulation system was developed in this study was verified the its reliability by the experimental results.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.417-420
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• 2001

The monitoring system for maintaining on-site wastewater treatment plants(Biofilter) was developed. Proposed system applied PLC(Programmable Logic Controller) technique. In process of development, the research against the monitoring parameters which will be able to represent condition and operation of the plants was accomplished. These parameters are ORP(Oxidation-Reduction Potential), Water Level, Pump and Power on/off. Also, to measure, collect, transfer and display these parameters, DMU(Data Measurement Unit), MCU(Main Controller Unit) and Display Board were produced.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.114-115
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• 2000

Halobacterium halobium에서 추출한 Bacteriorhodopsin(bR)을 고분자 물질에 첨가해 박막화하였다. 이 단백질 박막 소자의 photodynamic특성을 이용하여 광 switching system을 구성하였다. 광 switch system은 pump광을 이용해 B상태와 M상태에서 축퇴4광파 혼합방식으로 구성했다. Red, blue, violet 광원을 사용하여 B상태와 M상태 격자를 형성하고 on-off되는 위상공액신호를 측정했다. (중략)

• Journal of Chest Surgery
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• 제32권12호
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• pp.1123-1126
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• 1999

Coronary artery bypass grafting (CABG) technique has been much developed but CABG under cardiopulmonary bypass has the unavoidable deficits such as generalized inflammatory reaction from cardiopulmonary bypass and myocardial ischemia from aortic-cross clamp. There has been remarkable advancement of CABG without cadiopulmonary bypass. We performed CABG successfully without cardiopulmonary bypass. We performed CABG successfully without cardiopulmonary bypass in two patients with multivessel coronary disease who were failed to intervene with percutaneous transluminal coronary angioplasty. We herein report the two cases.

• 한국추진공학회지
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• 제13권3호
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• pp.20-26
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• 2009

30톤급 액체로켓엔진용 터보펌프에 대하여 실매질을 사용하여 성능시험이 이루어졌다. 산화제펌프와 연료펌프에는 각각 액체산소, 케로신의 실매질을 사용하고 터빈에는 고압의 상온 수소가스가 사용되었다. 터보펌프는 설계점과 탈설계점의 전 영역에서 안정적으로 작동하였고 요구되는 성능 조건을 만족 시켰으며 이로써 엔진 서브시스템 수준의 터보펌프 개발이 성능 측면에서 검증되었다고 볼 수 있다. 본 논문에서는 단일 운전으로 세 운용점에서 총 75초간 작동된 경우의 시험결과를 소개하였다. 펌프와 터빈의 성능 특성 관점에서 터보펌프 조립체의 실매질 성능시험 결과와 터보펌프 구성품의 상사 성능시험 결과가 양호하게 일치하였다.