• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3827-3834
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• 2012

Recently, instead of hot air type dryers that require a lot of heat, energy-efficient heat pump dryers have been used in various fields such as paper, textile, wood, food, etc. In this paper, the characteristics of heat pump cycle were theoretically evaluated with hot-gas bypass system to further improve the energy efficiency by minimizing the use of electric heaters in early warm-up stage of the dryers for frozen agricultural products. In addition, damper system that leads outside air to flow into the dryer were optimized to obtain extra heat for higher energy efficiency.

• Journal of Chest Surgery
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• v.22 no.1
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• pp.1-9
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• 1989

We have performed one case of autotransplantation and 11 cases of orthotopic homotransplantation using Korean mongrel dogs, and have scrutinized the hematologic and hemodynamic results. The mean weight of recipients was 15.42*1.2kg and varied from 14kg to 20kg. During the operation, anesthesia and other technical procedures including cardiopulmonary bypass were similar to the usual methods in human cardiac transplantation. It was found that the hematologic values were similar to those of human beings although there was wide variance. Hemodynamically the mean systolic and diastolic arterial pressures were 165.0* 12.9 mmHg and 100.0 *11.8 mmHg respectively, and the mean heart rate was 155.5*23.5/min. All cases died within 24hrs, and the mean survival in all but 6 cases where operative death occurred was 6.83*8.01 hrs[range 2-21 hrs]. The major causes of deaths were bleedings in 7 cases, failure to protect myocardium during the procedure in 2 cases, pulmonary edema in 1 case and multiorgan failure in 2 cases. From the above results we concluded that the most frequent complication was bleeding, and the cardiopulmonary bypass flow of 50-500ml/kg min was not suitable to the dog in CPB. In further experiment after this study, the technical and the bypass flow was increased. Bleeding was not significant. And the immunosuppresion during operation and postoperative period was tried.

• Nuclear Engineering and Technology
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• v.20 no.1
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• pp.47-53
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• 1988

The objective of this study is to evaluate the reliability of the High Head Safety Injection System (HHIS) of KNU 5, 6, 7 and 8 following the removal of safety injection signal (s-signal) from the mini-flow bypass line valves of charging/safety injection pumps. The unavailability of HHSIS and the rupture probability of a charging/safety injection pump have been computed for two different cases; with s-signal on and removed. The results show that when the s-signal is removed from the mini-flow bypass line valves, the unavailability of HHSIS slightly increases while the rupture probability of a charging/safety injection pump is significantly reduced. Hence, based upon the results of this study we conclude that it is more reasonable to remove the s-signal from the mini-flow bypass line valves of KNU 5, 6, 7 and 8 in the normal plant operation. And to improve the availability of HHSIS, the modification of operational procedures and the emphasis on operator training are recommended.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.1092-1100
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• 1989

Since May 1987 to April 1989, fifteen patients have been subjected to coronary artery bypass graft [CABG] including coronary thromboendarterectomy in 3 patients at Hanyang University Hospital. The correlation between the preoperative coronary angiography, electrocardiography, clinical status, operative finding and postoperative blood flow, complication and degree of clinical improvement were evaluated. 1. Ten patients [67 %] were male and five patients [33 %] were female, Ages ranged from 30 to 68 years. [average 52.2 years] 2. The angina by types of presentation was stable in 3 patients, unstable in 12 patients with resting, postinfarction and progressive angina as the criteria of unstability. 3. The number of involved vessels were single in 6 cases, double in 4 cases, triple in 5 cases including 1 case of left main coronary arterial disease. 4. The distribution of sites of distal anastomosis revealed predilection to left coronary arterial system [83 %], especially left anterior descending arterial system. 5. The author performed 4 cases of single bypass, 4 cases of double bypass, 5 cases of triple bypass and 2 cases of quadruple bypass. Of these 15 patients, 3 patients received coronary thromboendarterectomy, LAD in 2 patients and right coronary artery [RCA] in 1 patient. 6. The distal anastomosis were performed first with using saphenous vein grafts as conduits in all cases except 1 case using Gore-Tex conduit because of deficient in length and narrowed internal mammary artery and sequential bypass methods were employed in last 6 cases. 7. One operative death occurred and therefore, mortality rate was 6.7%. The perioperative myocardial infarction were occurred in 3 cases [20%] and its cause was supposed that they were triple vessel disease and therefore, aortic cross clamping times were relatively long. 8. All survivors were followed for 17.7 months on an average [range 5-28 months] and they have had symptomatic improvement except 1 case having mild degree of angina at 1.5 months after operation.

• Journal of Chest Surgery
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• v.25 no.5
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• pp.469-479
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• 1992

Searching for the clinical effects of colloid solutions that used to increasing the oncotic pressure of priming solutions at the cardiopulmonary bypass, 29 patients [who were diagnosised as simple VSD around 10kg of body weight and scheduled to be operated from June 1990 to December 1990 at Sejong General Hospital] were divided randomly and prospectively to the two groups: A group [15] was received 4gm% albumin as addition to the priming solutions and B Group [14] the same amount of Ringer`s lactated solution. 34 clinical parameters [Body weight, sex, age, body surface area, Qp/Qs, pulmonary arterial pressure, cardiopulmonary bypass time, anesthetic time, intraoperatively infused crystalloid and colloid amount, hemoglobin, hematocrit, serum sodium concentration, serum osmolarity, urine osmolarity, urine specific gravity, serum concentration, serum osmolarity, urine osmolarity, urine specific gravity, serum protein, serum albumin concentration, urine output, central venous pressure, postoperatively infused colloid amount, immedediate post-operative peak inspiratory pressure, cardiac index, blood pressure and pump flow during cardiopulmonary bypass, inotro-pic assist, diuretics, extubation period, total drain amount, duration of ICU] were measured and compaired between the two groups. There were no differences of preoperative and operative clinical parameters. And postoper-atively, practically there were no nearly differences at the clinical outcomes between the two groups, but some parameters [cardiac index, PIP, BP and pumpflow during CPB, etc] contributed to being preferable to the Group A at certain times [P<0.05]. Conclusively, it might be thought that the priming solution of cardiopulmonary bypass added by colloid solution had some beneficial effects on the patients, especially younger and associated with complex anomaly to be expected taken longer time of cardiopulmonary bypass, and more studies about the neonatal and complex anomaly cases were needed in that points.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.448-453
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• 2017

We conducted the three-dimensional fluid flow analysis in a Taylor reactor using computational fluid dynamics (CFD). The Taylor flow can be categorized into five regions according to Reynolds number, i.e., circular Couette flow (CCF), Taylor vortex flow (TVF), wavy vortex flow (WVF), modulated wavy vortex flow (MWVF), and turbulent Taylor vortex flow (TTVF), and we investigated the flow characteristics at each region. For each region, the shape, number and length of vortices were different and they influenced on the bypass flow. As a result, the Taylor vortex was found at TVF, WVF, MWVF and TTVF regions. The highest number of Taylor vortex was observed at TVF region, while the lowest at TTVF region. The numerical model was validated by comparing with the experimental data and the simulation results were in good agreement with the experimental data.

• Journal of Chest Surgery
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• v.23 no.5
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• pp.1021-1026
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• 1990

The patients with tracheal stenosis have become more increasing in recent due to the increased use of tracheostomy and assisted ventilation Anesthetic management during tracheal reconstruction is a concern to the anesthetist and the surgeon, who must share the airway as a operation field and at the same time provide good gas exchange. Multiple technique such as the tube ventilation system or C \ulcornerP bypass method have been recommended to achieve this goals. However, these methods have disadvantages of poor surgical exposure and hemorrhagic complication from using C \ulcornerP bypass The technique for HFJV was first described for bronchoscopy, and it involves positive-pressure breathing with high flow[40 \ulcorner60L/min] of oxygen This flow is directed to a semirigid catheter inserted in the endotracheal tube and the tracheal reconstruction can be done without interruption. From Dec. 1986 to July 1990 we have experienced 6 patients of tracheal stenosis necessitating circumferential resection and end to end anastomosis; 5 patients with tracheal stenosis following cuffed tracheostomy or intubation, a patient with tracheal stenosis due to invasive thyroid cancer. The specific advantages during tracheal reconstruction are unobstructed field during surgical reconstruction and good gas exchange through the procedure.

• Journal of Chest Surgery
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• v.25 no.1
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• pp.105-111
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• 1992

Total atherosclerotic obstruction of the juxtarenal abdominal aorta is a relatively rarely encountered form of atherosclerotic vascsular disease, accounting for less than 5% of all arterial obstrutive disease. We have encountered two patients with such lesions, both of whom were admitted for intermittent claudication of the lower extremities and symptoms of vascular ischemia. Digital subtraction angiography[DSA] was performed on both patients, the results of which revealed total obstruction of the aorta just inferior to the renal arteries without involving the latter. Operative technique involved the use of the sup-raceliac aorta as the site of proximal anastomosis of aortofemoral bypass followed by a fem-orofemoral bypass graft with Smm sized Woven Dacron[Vascutek] through a subcutaneous tunnel within the retroperitoneal space. Both patients experienced restoration of blood flow distal to the obstruction postoperatively without any complications, and OPD follow-up one month postoperatively and postoperative DSA showed evidence of continued graft patency with persistent symptomatic improvement.

• Journal of ILASS-Korea
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• v.24 no.2
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• pp.66-72
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• 2019

Diesel vehicles suffer from poor starting and running problems at cold temperatures. Diesel vehicles have the characteristic that CO and PM are reduced or similarly discharged when going from low temperature to high temperature. In this study, a bypass type piezo injector for electronic control based common rail injection system was used. Numerical analysis using injector drive analysis model was performed to analyze injector drive and internal fuel flow characteristics according to fuel temperature change. The results show that the rate of density change due to the fuel temperature is proportional, and that the effect of the kinematic viscosity is relatively large between $-20^{\circ}C$ and $0^{\circ}C$. Comparing the results of temperature condition at $0^{\circ}C$ and $20^{\circ}C$, it is considered that the viscosity is more correlated with the needle displacement than the pressure chamber of the delivery chamber.

• Journal of Korean Neurosurgical Society
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• v.45 no.5
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• pp.322-322
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• 2009