• Journal of Chest Surgery
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• v.17 no.3
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• pp.331-338
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• 1984

From 1959 to Jun. 30 84, 1144 cases of various cardiovascular diseases were operated consisting of 421 open heart surgery under extra-corporeal circulation or hypothermia and 723 conventional surgery at department of Thoracic and Cardiovascular Surgery in National Medical Center. There were 470 congenital anomaly and 674 acquired lesions. Out of 470 congenital anomaly, acyanotic anomaly was 289 and cyanotic anomaly was 181. Among 647 acquired lesions, 473 was cardiac lesion, 87 was pericardial lesion and 105 was vascular diseases. Over all operative mortality was 9.0%, consisting of 7.6% for acyanotic, 19.3% for cyanotic anomaly and 6.8% for acquired lesion. Mortality for 723 conventional surgery was 6.2%, and 421 open heart surgery was 13.8%.

• Proceedings of the KIEE Conference
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• 1999.11a
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• pp.16-19
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• 1999

This paper describes the electron transport characteristics in $SF_6$+He gas calculated for range of E/N values from $50{\sim}700[Td]$ by the Monte Carlo simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by TOF method. The results gained that the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.154-159
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• 1997

This paper describes the electron transport characteristic in SiH$_4$ gas calculated for range of E/N values from 0.5~300(Td) by the Monte Calro simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained for TOF method. The results gained that the value of an electron swarm parameter such as the electron drift velocity, the electron ionization coefficients longitudinal and transverse diffusion coefficients, characteristics energy agree with thee experimental and theoretical for a range of E/N. The electron energy distributions function were analysed in monosilane at EN : 30, 50(Td) for a case of equilibrium region in the mean electron energy. The validity of the results obtained has been confirmed by a TOF method.

• Journal of Chest Surgery
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• v.4 no.2
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• pp.91-94
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• 1971

Benign papillary tumors commonly arise in the upper respiratory tract but are rare in the lower respiratory tract, especially in the bronchi. Solitary benign papillary tumors arising at the bronchi,covered with stratified squamous epithelium and associated with little or no inflammatory cell response,seem to be rarest of all types of benign bronchial tumors. Only six cases of such tumors had been reported in the medical literature over the past 74 years until 1968. The following is a case report of solitary benign papilloma arising at the opening of the left main bronchus which was treated with bronchoscopic removal at Chest Surgery Depariment, N.M.C. on Sept.

• Journal of Chest Surgery
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• v.4 no.2
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• pp.95-100
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• 1971

The incidence of empyema has been drastically reduced with the advent of antimicrobial drugs,however,there is still complicated and difficult problems of management of empyema remaining. During the period of December, 1958 to December, 1962, 90 patients nf empyema thoracis were managed in the Department of Thoracic Surgery of the National Medical Center, and this series deals with the incidence,etiologic consideration, bacteriology and management of empyema with its result. 1] Male predominates with the ratio of 3.1: 1, and peak age incidence lies in 3rd decade. 2] Most common etiologic factor is bronchorespiratory infection among which tuberculosis remains highest incidence. 3] 56.7% of patients shows positive result of bacteriologic study and about half of positive culture series shows mixed infection or changing pattern of bacteriological strains during serial examinations. 4] Complete cure is obtained in 84.4% of patients with 5 deaths.

• Proceedings of the KIEE Conference
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• summer
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• pp.594-596
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• 2004

부식이나 경년열화 등으로 인한 변전소 접지성능 저하에 대한 대책마련을 위하여 정기적인 변전소 접지저항의 측정은 필수적이라고 한 수 있다 그러나 단지 접지저항의 측정을 위하여 변전소 접지망과 연결되어 있는 외부접지계통, 즉 배전 중성선이나 송전선로 가공지선의 다중접지계통을 분리한다는 것은 현실적으로 불가능한 작업이다. 본 논문에서는 접지시험을 위한 시험전류를 주입하고 가공지선 및 중성선으로의 분류계수를 측정함으로써 운전 중인 상태에서 변전소 접지망 단독의 접지저항을 측정하는 시스템, 측정기법 및 사례연구를 제 시 하였다.

• Journal of Welding and Joining
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• v.23 no.3
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• pp.34-39
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• 2005

It is required for the steel materials used in the sour environment to have sufficient resistance to hydrogen induced cracking(HIC). For line pipe steels, HIC resistance could be varied during pipe making process due to the large plastic deformation applied in the thick-wall pipe. In order to figure out such effect, HIC tests were performed not only in the plate condition but in the pipe condition and their results were compared in terms of cracking ratio. Test results demonstrated a detrimental effect of plastic deformation to HIC resulting in a substantial increase in the cracking ratio after pipe forming process. All of the cracks found in the pipe material were located in the outer layer of pipe where the tensile strain was resulted during pipe forming stage. In order to understand the HIC resistance of the pipe but in the plate condition, it was suggested to pre-strain the plate to some extent before the HIC test.

• Journal of Welding and Joining
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• v.32 no.5
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• pp.1-6
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• 2014

This study aims at manufacturing SA welded API-X70 line-pipe with sour gas resistance. A pipe was manufactured by JCO bending process and SA welding using the API-X70 plate guaranteed HIC resistance. SA welded pipe was expanded in order to reduce the residual stress. The evaluation of a pipe for resistance to HIC and SSCC were performed by the RS D 0004 and RS D 0005 standards. For verification that a pipe has acceptable resistance to HIC, fullscale test was carried out. Results showed no cracking for the HIC and SSCC.

• Journal of Chest Surgery
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• v.7 no.1
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• pp.61-66
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• 1974

Primary tumors of the chest wall are rare than those of other portions of the body. Soft tissue tumors of the chest wall, though these are benign or malignant, should not be paid special attentions about their management than other soft tissue tumors of the body. Thoracic skeletal tumors, however, have some problems in the treatment because of defect in chest wall leading to herniation of lung and paradoxical movement of thoracic cage. The authors experienced 10 case of primary chest wall tumors at the department of thoracic and cardiovascular surgery, the national medical center, during last 15 years. Five of 10 cases were soft tissue tumors, and they were 2 case of lipoma and each one case of myxosarcoma and leiomyosarcoma. Among 5 bone tumors there no cases of sternal tumor, and their histopathological diagnosis were each one of fibrous dysplasia, giant cell tumor, osteochondroma, Ewing`s sarcoma and osteogenic sarcoma. Wide excision, though it was palliative one in certain case, was performed in 9 cases and only diagnostic incisional biopsy in one case, There were no postoperative deaths during admission to the hospital and all cases were missed during short term follow up after discharge from the hospital.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.902-903
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• 2015

현재 세계는 각종 에너지에 대한 연구가 치열하게 진행되고 있는 가운데 각 기계들의 에너지 효율등급이 엄격하게 규제되고 있다. 전동기 분야에서는 사용 용도에 따라서는 영구자석을 쓰지 않는 유도기가 주목을 받았다. 하지만 유도전동기는 가공이 쉽지 않고 동일 사이즈에서 출력이 동기 릴럭턴스 전동기(Synchronous Reluctance Motor; SynRM)보다 낮기 때문에 현재 국내외 전동기 시장에서는 SynRM이 주목받고 있으며 현재 많은 연구가 진행되고 있다. 본 논문은 30kW급 팬 부하용 SynRM 설계에 관해 논문이다. 기존에 사용되었던 유도 전동기를 대체하기 위해 전동기의 자속장벽의 형상에 따라서 어떠한 효과가 있는지에 대해 연구하고 앞으로의 SynRM의 회전자 형상 설계 방법을 제시한다.