• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.5
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• pp.383-390
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• 2013

The reduction of the maximum acceleration which causes shock for a missile is very important to prevent abnormal operation of a missile and decrease size and cost of missile components. Because the maximum acceleration created by operation of an ejection gas generator occurs in the initial ejection stage, the design parameters which affect initial ejection stage were examined. The igniter and the nozzle closure were selected as design parameters of a gas generator. The maximum acceleration created by the gas generator was examined experimentally by changing of the design parameters. Finally the reduction effect of the maximum acceleration was compared quantitatively by static fire test of a gas generator. The maximum acceleration of the best model which was applied to each optimal design parameter was about 68% reduced than that of the reference model.

• Tuberculosis and Respiratory Diseases
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• v.69 no.2
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• pp.124-128
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• 2010

Septic pulmonary embolism is the process in which an infected thrombus becomes detached from its site of origin and lodges in a pulmonary artery, and is usually associated with infective endocarditis, especially right-sided, or infection-associated with indwelling catheters, peripheral septic thrombophlebitis, and periodontal diseases, etc. Here, we report a case of septic pulmonary embolism associated with tricuspid valve infective endocarditis. A 23-year-old female was admitted to our hospital, due to fever, sore throat, and myalgia. In her past medical history, she had undergone a surgical operation for closure of a ventricular septal defect, but was informed that the operation resulted in an incomplete closure. The initial chest radiograph demonstrated multiple rounded, parenchymal nodules in various sizes; several nodules had central lucency suggesting cavitations. Echocardiography demonstrated a large vegetation attached to the septal tricuspid valve leaflet, extending from right ventricular inflow tract to outflow tract. Computed tomography of thorax revealed bilateral peripheral nodules and wedge-shaped consolidation at various sizes, mostly accompanied by cavitations.

• Archives of Plastic Surgery
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• v.34 no.2
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• pp.197-202
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• 2007

Purpose: The gluteal artery perforator flaps earned its popularity in buttock reconstruction due to the lower morbidity of the donor site and the flexibility in the design. Speedy and safe reconstruction is important for the success of buttock reconstruction. If a proper design is selected, satisfactory results can be obtained with more simple method of surgery. Methods: Between April 2005 and April 2006, buttock reconstruction by using gluteal artery perforator flaps were performed on sacral sores(6 cases), ischial sores(2 cases) and malignant melanoma on buttock(1 case). Various designs depending on the location and the size of the defect was made. In those designs, perforator was used as an axis for the minimal dissection of the vessel. Donor site from which sufficient amount of soft tissue can be transferred was selected, and also not causing high tension against the recipient site during the donor site closure. In addition, postoperative aesthetics, and the possibility of another design of a second operation which can be necessary in the future, was considered. Results: Patient follow up was for a mean period of 10.8 months. All flaps survived except for one that had undergone partial necrosis. Wound dehiscence was observed in one patient treated by secondary closure. Most patients presented with cosmetically and functionally satisfying results Conclusion: By designing the flap using the perforator as an axis, depending on the defect size and degree, reconstruction can be performed with only a small tension to the donor and the recipient site. And the minimal perforator dissection allowed easier and faster reconstruction. Selection of a proper design is the key procedure which greatly affects operation time and result success.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.5
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• pp.1-11
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• 2001

In the past, abundant and clean water was available for paper mills'use. However, the growth of population and industry made water less available nowadays. Also, environmental regulation limits wastewater discharge, which affects mill operation cost. Therefore, paper mills are under pressure to use more recycled water and mill system closure. As a result, chemical and physical parameters of water are changing and new environment if being created for microorganisms in paper mill system as well. The more soluble or suspended organic materials are increased as more water is recycled and less or scarce dissolved oxygen is available, depending on the degree of recycled water usage. Microorganism flora ill paper mill system will be a1so shifted according to the environmental change of mill system. Anaerobic bacteria, including sulfate reducing bacteria (SRB), will be dominant in the system as very low or almost no oxygen available in the system. Nevertheless, it is common in domestic paper mills that employ the same and old biocides as a means of microbial control, and microbiological control is often less recognized or even neglected. The right biocide selection for increased reductive environment of mills is critical for operation and estimated loss from paper quality defects such as sheet break, holes due to microbiological cause is tremendous compared to the microbiological control cost. It is imperative to investigate and diagnosis the environmental change of mills for right control of cumbersome microorganisms. Several useful diagnosis tools, including new technology employing OFM(Optical Fouling Monitor) in situ, are illustrated.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.161-170
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• 1987

Fifty-nine cases of congenital chest wall defects experienced in the department of thoracic surgery of Seoul National University Hospital were analyzed and the relevant literatures were reviewed. They are 52 cases of funnel chest, 3 cases of pigeon breast, one case of superior sternal fissure, one case of costochondral incurvation, one case of Cantrell`s pentalogy, and one case of Poland`s syndrome. Funnel chest affected males more frequently than females by 44 to 8. All of the funnel deformities were corrected by Ravitch operation or its modification except one which was the first case of this series and was corrected by a sterno-turnover. Two cases required a mechanical ventilation for 3 days and 5 days respectively. Four minor complications which were two cases of skin wound infection and 2 cases of fluid accumulation were noted. Skin would infection was repaired by a secondary closure and fluid accumulation was treated by aspiration only. The result are all excellent without recurrence or reoperation. In 3 cases of pigeon breast, they were treated by subperichondrial resection of all of the involved costal cartilages and shortening their course with reefing sutures in the perichondrium with excellent result. The superior sternal fissure which was combined by a ventricular septal defect was treated by a simple wire closure with a good result. The costochondral incurvation was corrected by subperichondrial resection of deformed cartilages and a rib graft removed from the contralateral normal side. The Poland syndrome and the Cantrell`s pentalogy was already presented previously.

• Journal of Chest Surgery
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• v.25 no.10
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• pp.1055-1060
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• 1992

Clinical experience of 21 patients with infective endocarditis was reviewed. Endocarditis involved the left-sided valve in 16 cases, the right-sided valve in 2, and PDA in the remaining 3 patients. Valve abnormalities included leaflet perforation in 9 patients, chordal rupture in 2,; annular abscess in 6; and aorticoleft atnal perforation in 2. Sixteen patients underwent valve replacement[aortic valve replacement in 7 patients, mitral replacement in 4 and double valve replacement in 5], two had VSD closure with pulmonary valve excision, three had ductus arteriousus closure. The patients were classified into two groups. I ] Healed endocarditis group: including the patients who had completed a planned cou-rseof antibiotic therapy[N=10], II ] Active endocarditis group: patients in which operations were performed prior to completetion of antibiotic treatment course[N=11]. The indications for operation included congestive heart failure, embolism, and persistent sepsis. Organisms were predominantly streptococcus[N=5] and staphylococcus [N=4] followed by candida, moraxella, and E-coli. By NYHA functional classification, all patients were in Class III or IV preoperatively. There was only one operative mortality in patient from group II. All patients substantially, improved postoperatively with NYHA classification in class I or II. This study shows that early surgical intervention in patients with active endocarditis has desirable outcome.

• Journal of Chest Surgery
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• v.43 no.4
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• pp.409-412
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• 2010

We have experienced five cases of atrial septal defect closure under complete port access using the da Vinci system. We used only six 8∼12 mm ports without thoracotomy or sternotomy for operation.

• Journal of Chest Surgery
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• v.26 no.11
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• pp.845-850
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• 1993

Post-Pneumonectomy Empyema[PPE] is a relatively uncommon but serious complication. And the management of it remains a disturbing and controversial area in the field of general thoracic surgery. Many methods have described and have had varying degrees of success. For the purpose of providing the guideline for management of post-pneumonectomy empyema, we reviewed our experiences of treatment of PPE from January 1985. to December 1992. There were 17 cases, which consist 7.9% of all pneumonectomy cases for that period. There were 13 male and 4 female patients with mean age of 47.1$\pm$ 16.2 yrs old. Both chest has the same incidence. The most common disease for prior pneumonectomy was tuberculosis, but the PPE was the most frequently occurred in empyema. The duration between pneumonectomy and PPE was 44.7 $\pm$81.1 months, where 58.8% of patients occurred within 1 month. Fever was the most frequent complaint and wound dischrge was detected in less than half of patients. There were 2 in-hospital mortalities.Mostly, in 13 cases, we did Eloesser operation. Five of them could finish second Clagett procedure, but one had recurrence. Four bronchopleural fistular patients underwent 3 single stage muscle flap closure and 1 direct closure with modified Clagett procedure. None had recurrence. Mean follow-up duration is 30.9\ulcorner22.3 months. There was 1 late death which was not related to PPE but to Malignancy recurrence.

• Journal of Chest Surgery
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• v.27 no.1
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• pp.24-30
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• 1994

Eighteen infants with a large ventricular septal defect[VSD] underwent primary surgical repair from January 1986 to December 1992. Operation was done because of failure to thrive, medically intractable heart failure, recurrent pneumonia, increased pulmonary vascular resistance[PVR]. Four patients[22.2%] died in the early postoperative period. Relief of heart failure and normalization of growth and weight gain was evident in all survivor. There was no late postoperative death. The results of primary surgical repair of VSD in infancy are compared with those of palliative pulmonary artery banding[PAB] and of VSD closure after PAB. Twenty-seven patients with isolated VSD or with VSD associated with atrial septal defect, patent ductus arteriosus, or coarctation of the aorta underwent initial palliative PAB. There were 3 early postoperative deaths[11.1%]. Severe elevation of PVR persisted in two patients. Closure of VSD and pulmonary artery debanding was done in twenty patients, with 2 early postoperative deaths[10.0%]. Placement of the PAB too close to the pulmonary annulus necessitated trasannular patching in one patient, but any problem caused by migration of the band was not developed. It is concluded that primary surgical repair of VSD in infancy is reasonable and that PAB is indicated only for those patients less than 6 months old with a complicated defect or in an emergency situation.

• Journal of Chest Surgery
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• v.48 no.1
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• pp.59-62
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• 2015

Interventional device closure has emerged as a less invasive alternative to surgery in the management of paravalvular leakage. However, this procedure involves various problems such as a high probability of residual leakage or hemolysis. Here, we report a case of residual paravalvular leakage despite two attempts at interventional closure in a patient with a history of four previous mitral valve replacements. The fifth operation for the primary repair of paravalvular leakage was performed successfully. Careful evaluation before the procedure and specially designed devices are essential for the interventional treatment of paravalvular leakage. Surgery can be performed adequately in the management of paravalvular leakage even in high-risk patients.