• Journal of Chest Surgery
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• 제27권10호
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• pp.862-867
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• 1994

We experienced two cases of dissecting aneurysm[DeBakey type III] of the thoracic aorta treated using intraluminal sutureless graft. Controversy still exists about the exact timing of surgical intervention for dissection of the descending thoracic aorta. The surgical indication of dissecting aneurysm[DeBakey type III] is continuous flow in the false lumen, continuous chest pain, compromise of arterial supply to a specific organ or limb, or extension of the dissection while the patient is receiving satisfactory medical treatment. Surgical therapy for dissection of the aorta has had a high mortality. One contributing factor has been hemorrhage from the prosthesis and the suture lines. Recently, a new method of treatment with a intraluminal sutureless graft that requires no end-to-end anastomosis has been developed. In our cases, cardiopulmonary bypass and circulatory arrest was utilized in repairing dissecting aneurysm of descending aorta[DeBakey type III] in order to avoid the aortic cross clamping because of friable aortic intima. The basic technique consists of vertical incision of descending aorta in the area of intimal tear and inserting the whole ringed graft into the true lumen of the dissected aorta and circumferentially ligating the aorta against the groove in the rings. Postoperative course was uneventful.

• Journal of Chest Surgery
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• 제44권6호
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• pp.423-426
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• 2011

We report on two women who underwent myocardial revascularization associated with antiphospholipid syndrome (APS) with different pathogenic patterns. The first woman presented with acute myocardial infarction, and preoperative angiograms demonstrated rapidly progressing coronary lesions, presumptive unstable plaque, and dissection. Operative findings, however, showed fresh thrombi in the coronary arteries, and she was diagnosed postoperatively as having APS. Her one-year angiogram demonstrated improved coronary lesions and a competitive flow pattern in the grafts. The second woman presented with unstable angina and had been treated for systemic lupus erythematosus and secondary APS for more than 14 years. She underwent myocardial revascularization due to accelerated coronary atherosclerosis. Her one-year angiogram demonstrated patent grafts.

• Journal of Chest Surgery
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• 제43권4호
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• pp.441-446
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• 2010

이상적인 도관은 직경이 커야 하고, 조직 독성이 적으며 감염에 강하고 장기 성적도 좋아야 한다. 대복재정맥은 실제에서 많이 사용되고 있지만 만족할 만한 혈류를 위해서는 때때로 시간을 기다려야 할 필요가 있다. 저자들은 단시간 내 적절한 혈류확보를 위한 생체도관으로서 표재성 대퇴정맥을 사용한 2예를 보고한다.

• 동력기계공학회지
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• 제14권2호
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• pp.28-33
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• 2010

In this research, cascade liquefaction process was simulated using two-staged direct expansion with inter-cooler. Evaporated gaseous refrigerant which has low pressure and temperature from the inter-cooler is mixed with gaseous refrigerant from outlet of 1st compressor, and flows into 2nd compressor. Therefore this prevents superheating compression. Compressor work of process which includes inter-cooler to all cycles shows the lowest value of 338.68 MW and it is lower 16.34% than that of basic process. Refrigeration capacity shows decreasing tendency as applied inter-cooler and that of process which includes inter-cooler to all cycles shows the lowest value of 449 MW. COP was increased when the inter-cooler was applied, and process which includes inter-cooler to all cycles shows highest value of 1.33. It shows that COP was increased because decrement of compressor work by applying inter-cooler was higher than decrement of refrigeration capacity.

• Advances in biomechanics and applications
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• 제1권4호
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• pp.279-292
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• 2014

This paper presents some simulations of fluxes and pressures in the coronary network, in the case of very severe coronary disease (several stenoses on the left branches and total occlusion of the right coronary artery). In that case, coronary artery bypass graft surgery is the commonly performed procedure. However, the success of the intervention depends on many factors. Modeling of the coronary circulation is thus important since it can help to understand the influence of all these factors on the coronary haemodynamics. We previously developed an analog electrical model that includes the eventual presence of collateral flows, and can describe the different revascularization strategies (two grafts, three grafts, ...). The aim of the present work is to introduce in our simulations the time-dependence of the coronary microvascular resistances, in order to better represent the effect of the systolic ventricular contraction (which induces an elevation of the resistances because the vessels are squeezed).

• 한국유체기계학회 논문집
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• 제15권6호
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• pp.46-50
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• 2012

A high-speed centrifugal pump requires more attention to the control of its axial thrust due to the high discharge pressure than a conventional industrial pump. Vanes employed toward the rear cavity of the impeller can be an effective device to control the axial thrust of the pump. The vanes disturb circumferential flow of the cavity and it can modify the axial force acting on the impeller. In this paper, three types of vanes are installed in the high-speed centrifugal pump for liquid rocket engines and the thrust of the pump is measured with an additional thrust measurement unit. According to the results, shapes of cavity vanes have effects on the axial thrust of the pump. As the height of vanes increases, the outlet pressure of the rear floating ring seal decreases which results in a decrease of the thrust. On the other hand, head of the pump is almost same regardless of cavity vanes. Also, the pressure drop of the bypass pipeline increases when vanes are removed.

• Journal of Chest Surgery
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• 제14권3호
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• pp.187-194
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• 1981

Cardiac surgery is generally followed by a period of routine ventilator support. When the patient seems hemodynamically stable and relatively alert following surgery, respiratory adequacy is tested by the weaning trial. In this study, physiological and clinical prediction of postoperative respiratory adequacy, including values of pulmonary function tests, were examined in an attempt to identity those few variables which predicted the outcome of the ventilator weaning trial following surgery. Our series comprised 27 patients who underwent elective open intracardiac operations at the Department of Thoracic and Cardiovascular Surgery, School of Medicine, Kyungpook National University, from October 1979 to July, 1980. The pulmonary function tests performed on all patients included the following; forced vital capacity [FVC], forced expiratory volume [FEV1.0], forced expiratory flow [FEF 25--75~], residual volume [RV], and functional residual capacity [FRC], measured with a helium dilution technique. Of our 27 patients, 8 were successfully weaned within 20 hours of operation. All patients with cyanotic heart diseases or acquired heart diseases were unsuccessfully weaned. The bypass time in the successful weaning group was shorter in the mean value [82.8 minutes]than in the unsuccessful weaning group [120.5 minutes]. There was a relatively significant difference in the mean values for the two groups in arterial pressure, bleeding amounts and FiO2 among the postoperative monitoring variables, and in forced vital capacity [FVC]. The postoperative clinical assessments appeared vague but corresponded reasonably well to appraisal of success in weaning, especially in variables of cough and self-respiration efforts.

• Journal of Chest Surgery
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• 제14권3호
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• pp.302-306
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• 1981

Aorticopulmonary window is a rare anomaly among congenital heart disease. Various terms have been suggested including A-P window, A-P fenestration, fistula, aorticseptal defect etc. The defect lies usually between the left side of the ascending aorta and right wall of the pulmonary artery just anterior to the origin of the right main pulmonary artery. We have experienced one case of aorticopulmonary septal defect which was diagnosed as V5D with pulmonary hypertension in 1 4/12 year old, 7.2 Kg, male patient. Operation was done under the hypothermic cardiopulmonary bypass using 5t. Thomas cardioplegic solution. Vertical right ventriculotomy over the anterior wall of RVOT revealed no defect in the ventricular septum, and incision was extended up to the main pulmonary artery to find the source of massive regurgitation of blood through MPA. Finger tip compression of the aorticopulmanary window was replaced with Foley bag catheter balloon, and the $7{\times}10$ mm aorticoseptal defect located 15mm above the pulmonic valve was sutured continuously wih 3-0 nylon suture during azygos flow of cardiopulmonary cannula which was located distal to the window resulted massive air pumping systemically, and temporary reversal of pumping was tried to minimize cerebral air embolism. Remained procedure was done as usual, and pump off was smooth and uneventful. Postoperatively, patient was attacked frequent opistotonic seizure with no recovery sign mentally and p.hysically. Vital signs were gradually worsen with peripheral cyanosis and oliguria, and cardiac activity was arrested 1485 minutes after operation. Autopsy was performed to find the sutured window and massive edema of the brain.

• Nuclear Engineering and Technology
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• 제29권3호
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• pp.229-239
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• 1997

To investigate the realistic behavior of mass and energy release and resultant containment response during large break Loss of Coolant accident (LOCA), analyses are performed for Yonggwang (YGN) 3&4 nuclear power plants by using a merged version of RELAP5/CONTEMPT4 computer code. Comparative analyses by using conservative design computer codes are also peformed. The break types analyzed are the double-ended guillotine breaks at the cold leg and hot leg. The design analysis resulted in containment peak pressure during post-blowdown phase for the cold leg break. However, the RELAP5/CONTEMPT4 analyses show that the containment pressure has a peak during blowdown phase, thereafter it decreases monotonously without the second port-blowdown peak. For the hot leg break, revised design analysis shows much lower pressure than that reported in YGN 3&4 final safety analysis report. The RELAP5/CONTEMPT4 analysis shoos similar trend and confirmed that the bypass flow through the broken loop steam generator during post-blowdown is negligibly small compared to that of cold leg break. The low pressure and temperature predicted tv realistic analysis presented in this paper suggest that the design analysis methodology contains substantial margin and it can be improved to provide benefit in investment protection, such as, relaxing plant technical specifications and reducing containment design pressure.

• 한국유체기계학회 논문집
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• 제15권5호
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• pp.27-31
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• 2012

Turbine inlet temperature is steadily increasing to achieve high specific thrust and efficiency of gas turbine engines. Turbine cooling technology is essential to increase turbine inlet temperature. For this study, a small or medium sized aircraft engine of 10,000 lbf class with the turbine inlet temperature of $1,400^{\circ}C$, the engine overall pressure ratio of 32.2, and the bypass ratio of 5 was set as the baseline model and its performance analysis was performed at the design point. The engine has the performance of 10,013 lbf thrust and the specific fuel consumption of 0.362 lbm/hr/lbf. The thrust and the specific fuel consumption of the baseline model were compared with those of similar class engines. Based on these results, the turbine design requirements were assigned. In addition, the parametric analysis of the engine, related to aerodynamic and cooling design of the high pressure turbine, was performed. Based on the baseline model engine, the influence of turbine inlet temperature, cooling flow ratio, and high pressure turbine efficiency variations on the engine performance was analyzed.