• 대한핵의학회:학술대회논문집
• /
• 2004.11a
• /
• pp.389.1-389.1
• /
• 2004

• Journal of Chest Surgery
• /
• v.15 no.2
• /
• pp.259-265
• /
• 1982

We have designed a new type of bubble oxygenator (KOREA-KIM VENOTHERM OXYGENATOR) made of PVC sheet and deforming mesh incorporated in the heat exchanger, and evaluated in experimental animal for the analysis of it`s efficiency. The Oxygenator has low priming volume with high flow rate up to 6 L/rain, and efficiency of heat exchanger was excellent as 1-$1.5^{\circ}C.$ using total cardiopulmonary bypass method under moderate to deep hypothermia. Average priming volume of 1317 ml with 30% hemodilution method was perfused with an average of 1.1-3.0 L/min.$M^2$of arterial blood and pure oxygen at a rate of 2-3.4 L/min for 49.6 minutes continuously in average. During total cardiopulmonary bypass, average $PaO_2$ was $159.8{\pm}60$mmHg, $PaCO_2$ $41.0{\pm}3$mmHg respectively under $SaO_2$ over 96% with systolic arterial pressure of 70 mmHg and CVP of 5-10 cm$H_2O$. Plasma free Hemoglobin was $7.0{\pm}4$ mg/dl with 25% drop of hemoglobin and hematocrit at the end of cardiopulmonary bypass. This KKV Oxygenator was observed to have excellent capabillty of oxygen and carbon dioxide gas transfer with small amount of blood trauma, and the efficiency of heat exchanger was satisfactory during cooling and rewarming of the bubbled blood. Disadvantages have included the somewhat poor deforming effect due to loose PVC fiber mesh, the extracompact character of Teflon filters, and the rough inner surface of the heat exchanger copper pipes.

• Journal of Chest Surgery
• /
• v.37 no.2
• /
• pp.176-179
• /
• 2004

A 30 year-old female patient was admitted for dizziness and palpitation. Pulsation of the both upper extremities and both common carotid arteries were absent. Innominate artery and both common carotid arteries were severely narrowed and both subclavian arteries were completely obstructed on aortogram. The patient was diagnosed as tvue Ⅰ Takayasu's arteritis, and operation was peformed to increase blood flow to the brain and both upper extremities. Ascending aorta, both carotid arteries, both subclavian arteries, and both axillary arteries were exposed by four separate incision, and we performed an aorto-bicarotid-biaxillary bypass with Hemashield graft. Previous dizziness and palpation were disappeared after the operation.

• Journal of Chest Surgery
• /
• v.28 no.1
• /
• pp.73-77
• /
• 1995

We are reporting one case of right subclavian vein thrombotic occlusion as a result of previous hemodialysis catheter placement in a patient with a functioning right brachio-cephalic arteriovenous fistula. Its complication was painful right arm swelling, limitation of motion and cellulitis. Diagnosis was confirmed by right subclavian venography and the complication was successfully managed by right subclavian vein-superior vena cava bypass with a GoreTex vascular graft. The arteriovenous fistula had remained to protect patency of the bypass at first, but two months later after the operation, the arteriovenous fistula had to be occluded because of the heart failure resulting from shunt over flow. After ligation of arteriovenous fistula, heart failure improved, and uncomfortable arm swelling did not develop again.

• Korean Journal of Optics and Photonics
• /
• v.27 no.6
• /
• pp.218-222
• /
• 2016

The thermal characteristics of a laser diode TO package has been analyzed using a commercial computational fluid dynamics (CFD) tool, and the thermal bypass structure was optimized. Comparison of device temperature and the estimated thermal resistance of the resultant structure showed that the bypass structure relieved the thermal bottleneck, and improved the thermal characteristics quite efficiently.

• Journal of Korean Society on Water Environment
• /
• v.20 no.2
• /
• pp.132-144
• /
• 2004

The purpose of this study was to evaluate alternatives for stable operation of WWTP(Wastewater Treatment Plant) with a higher rate of inflows and a higher concentration of pollutants during wet weather to minimize the pollution loads being discharged into receiving waters. 3Q(Q: dry weather flow) of a base flow is normally intercepted and flows into WWTP as it was current practice. It is revealed by simulation that the bypassing alternative of 1Q through secondary treatment and 2Q into the stream after primary treatment was as good as it is expected. The bypass pollution loads were in the range of 23.9 ~ 38.5 % of the total loads flowing into the WWTP indicating that the bypassed flows need an extra treatment such as stormwater detention reservoir, high-rate coagulation with sedimentation, and step-feed. The high-rate coagulation with sedimentation was the most effective with respect to removal of the pollution loads.

• Journal of Chest Surgery
• /
• v.45 no.6
• /
• pp.351-367
• /
• 2012

This second report in the series on coronary artery bypass presents the authors experience and personal views on the internal thoracic artery (ITA) which date to 1966. There has been a very gradual evolution in the acceptance of this conduit which was initially compared with the saphenous vein and viewed as an improbable alternative to it. As is common with concepts and techniques which are 'outside the box' there was skepticism and criticism of this new conduit which was more difficult and time consuming to harvest for the surgeon who had to do it all. It was viewed as small, fragile, spastic and its flow capacity was questioned. Only a few surgeons employed it because of these issues and some of them would frequently graft it to the diagonal artery as it was thought not to supply adequate flow for the left anterior descending unless it was small. After a decade, angiographic data revealed superior patency to vein grafts. Even this evidence and survival benefit reported a few years later did not convince many surgeons that their concerns about limitations justified its use. Thus widespread adaption of the ITA as the conduit of choice for the anterior descending required another decade and bilateral use is only now expanding to more than 5% of patients in the US and somewhat faster in other countries.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.78-81
• /
• 2009

A series of hydraulic tests of a fuel pump are performed using water at a room temperature. The pump is under development for 75-ton class liquid rocket engines of the open-loop gas generator type. According to the test results, the fuel pump satisfies its design requirement and its head and efficiency at the design flowrate are higher than the expected value by the computational analysis. Also, it is found that the pressure at the rear bearing outlet is higher than expected because the inlet of bypass pipe line is narrow. Furthermore, the flowrate of the secondary flow is estimated using the pressure difference of the elbow of the bypass pipe line.

• 유체기계공업학회:학술대회논문집
• /
• 2000.12a
• /
• pp.337-344
• /
• 2000

A modified k-$\epsilon$ model is proposed for calculation of transitional boundary layer flows. In order to develop the eddy viscosity model for the problem, the flow is divided into three regions; namely, pre-transition region, transition region and fully turbulent region. The pre-transition eddy-viscosity is formulated by extending the mixing Length concept. In the transition region, the eddy-viscosity model employs two length scales, i.e., pre-transition length scale and turbulent length scale pertaining to the regions upstream and the downstream, respectively, and a university model of stream-wise intermittency variation is used as a function bridging the pre-transition region and the fully turbulent region. The proposed model is applied to calculate three benchmark cases of the transitional boundary layer flows with different free-stream turbulent intensity ( $1\%{\~}6\%$ ) under zero-pressure gradient. It was found that the profiles of mom velocity and turbulent intensity, local maximum of velocity fluctuations, their locations as well as the stream-wise variation of integral properties such as skin friction, shape factor and maximum velocity fluctuations are very satisfactorily Predicted throughout the flow regions.

• 유체기계공업학회:학술대회논문집
• /
• 2002.12a
• /
• pp.419-424
• /
• 2002

The HANARO, a multi-purpose research reactor of 30 MWth open-tank-in-pool type, has been under normal operation since its initial criticality In February, 1995. Many experiments should be safely performed to activate the utilization of the HANARO. A flow simulation facility is being developed for the endurance test of reactivity control units for extended life times and the verification of structural integrity of those experimental facilities prior to loading in the HANARO. This test facility is composed of three major parts; a half-core structure assembly, flow circulation system and support system. The flow circulation system is composed of a circulation pump, a core flow pipe, a core bypass flow pipe and instruments. The system is to be filled with de-mineralized water and the flow should be met the design flow to simulate similar flow characteristics in the core channel of the half-core test facility to the HANARO. This paper, therefore, describes an analytical analysis to study the flow behavior of the system. The computational flow analysis has been performed for the verification of system pressure variation through the three-dimensional analysis program with standard k-$\epsilon$ turbulence model and for the verification of the structural piping integrity through the finite element method. The results of the analysis are satisfied the design requirements and structural piping integrity of flow circulation system.