• 한국추진공학회지
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• 제20권4호
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• pp.104-111
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• 2016

고속으로 흡입되는 공기를 산소원으로 이용하는 공기 흡입추진기관에서 해결해야 할 과제 중에 하나는 화염 안정화이다. 블라프보디와 같이 유동 감속장치를 설치하여 와류에 의한 재순환 영역을 만들어 주는 방법이 대표적인 방법이다. 최근에는 유동 벽면에 캐비티를 설치하여 화염을 안정화 시키는 것이 안정화 영역을 넓이는 효율적인 방안으로 대두되고 있는데, 캐비티에서의 유동 박리와 재접촉, 압력과 진동을 포함하여 길이와 깊이 비 등에 대한 영향 등이 조사 발표되고 있다. 그럼에도 불구하고 공기 흡입추진기관의 연구 개발과 함께, 선행 기술로서 캐비티를 이용한 화염 안정화에 대하여는 아직도 연구조사 되어야 할 과제가 많이 있다.

• Journal of Chest Surgery
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• 제11권1호
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• pp.65-68
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• 1978

The unusual congenital anomaly, double chambered right ventricle due to aberrant muscle band with intact ventricular septum in 10 years old female patient is presented. The pressure gradient is 70mmHg between inflow tract and outflow tract of right ventricle and the aberrant muscle band is 2X4.5cm arising below the infundibulum and traverses the right ventricular cavity, extending from its anterior wall to the crista supraventricularis forming broad triangular base in parietal anterior wall. By resecting out this muscle band clearly, the outflow tract obstruction is completely relieved.

• Journal of Radiation Protection and Research
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• 제26권3호
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• pp.271-273
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• 2001

In precise measurement of air kerma with cavity ionization chambers, the effect of wall attenuation and scatter are corrected by Kwall and that of nonuniformity by Knu. Using the EGS4 code, we calculated these two correction factors. Correction factors calculated for two different-sized cylindrical ionization chamber differ by up to 0.7% from those obtained by measurements.

• Journal of Chest Surgery
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• 제25권11호
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• pp.1240-1244
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• 1992

Human sparganosis caused by Sparganum mansoni, the larval plerocercoid worm of the genus Spirometra, is not uncommon in Korea and is mostly found in subcutaneous or adipose tissue of the abdominal, thoracic wall and inguinal region, but is rarely found in the orbital cavity, brain and breast. It, at present, is a surgical disease because its diagnosis depends almost on the demonstration of the larva[e] from lesion or finding the worm section in surgical pathology specimens. We experienced a case of human sparganosis from a 48 years old woman who had a history of eating a raw frog. We report the case and review the related literatures.

• Journal of Chest Surgery
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• 제12권2호
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• pp.97-100
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• 1979

Primary intrathoracic neoplasms occur frequently, and the most frequent intrathoracic tumors are of pulmonary or bronchogenic origin. Second in frequency are mediastinal tumors, and least frequency or comparatively rare are the neoplasms arising from the wall of the thorax and extending into the thoracic cavity. Of all intrathoracic tumors, fibroma is extremely rare. Recently, we have experienced a huge rapid growing intrathoracic fibroma originating from thoracic wall, which is removed successfully and confirmed histopathologically. Authors present one case of fibroma and discussion with a brief review of the relevant literatures.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.639-643
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• 2002

The main purpose of this study was to investigate the formation mechanisms of imperfections such as irregular humps, outer cavity and inner cavity in the laser fusion zone of diamond saw blade. Laser beam welding was conducted to join two parts of blade; mild steel shank and Fe-Co-Ni sintered tip. The variables were beam power and travel speed. The microstructure and elements distributions of specimens were analyzed with SEM, AES, EPMA and so on. It was found that these imperfections were responded to heat input. Irregular humps were reduced in 10.4∼17.6kJ/m heat input range. However there were no clear evidences, which could explain the relations between humps formation and heat input. The number of outer cavity and inner cavity decreased as heat input was increased. Considering both possible defects formations mechanisms, it could be thought that outer cavity was caused by insufficient refill of keyhole, which was from rapid solidification of molten metal and fast molten metal flow to the rear keyhole wall at low heat input. More inner cavities were found near the interface of the fusion zone and sintered segment and in the bottom of the fusion zone. Inner cavity was mainly formed in the upper fusion zone at high heat input whereas was in the bottom at low heat input. Inner cavity was from trapping of coarsened preexist pores in the sintered tip and metal vapor due to rapid solidification of molten metal before the bubbles escaped.

• 폴리머
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• 제32권6호
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• pp.501-508
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• 2008

렌즈나 휴대폰 부품 같은 소형 플라스틱 부품들은 일반적으로 다수 캐비티 사출금형에서 성형된다. 이러한 다수 캐비티 금형에서의 사출성형은 캐비티간의 충전 불균형이 일어날 수 있다. 이러한 충전 불균형 현상은 제품의 치수 및 중량의 편차뿐 아니라 제품의 물리적 특성에도 영향을 미친다. 충전 불균형은 무엇보다도 기하학적으로 균형 잡히지 않은 delivery system의 설계에서 기인된다. 하지만 delivery system이 기하학적으로 균형 있게 설계가 되었다 하더라도 충전 불균형 현상은 여전히 발생된다. 이러한 현상은 런너 단면에서의 온도분포에 기인하며 사출성형 공정 중 사출속도에 크게 영향을 받는 것으로 본 연구에서 파악되었다. 즉 충전 불균형은 부적절한 사출 성형 공정에 의해 발생되며 성형 공정 조건 중 사출속도는 충전에 영향을 주는 매우 중요한 요소이다. 본 연구에서는 재료와 사출 속도에 따른 충전 불균형 현상을 실험과 CAE을 통하여 관찰하였다. 사출속도 변화에 따른 충전 불균형 때문에 시편의 치수 및 무게가 불균일함을 확인하였다.

• International Journal of Korean Welding Society
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• 제2권1호
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• pp.21-24
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• 2002

The main purpose of this study was to investigate the formation mechanisms of imperfections such as irregular humps, outer cavity and inner cavity in the laser fusion zone of diamond saw blade. Laser beam welding was conducted to join two parts of blade; mild steel shank and Fe-Co-Ni sintered tip. The variables were beam power and travel speed. The microstructure and elements distributions of specimens were analyzed with SEM, AES, EPMA and so on. It was found that these imperfections were responded to heat input. Irregular humps were reduced in 10.4∼l7.6kJ/m heat input range. However there were no clear evidences, which could explain the relations between humps formation and heat input. The number of outer cavity and inner cavity decreased as heat input was increased. Considering both possible defects formations mechanisms, it could be thought that outer cavity was caused by insufficient refill of keyhole, which was from rapid solidification of molten metal and fast molten metal flow to the rear keyhole wall at low heat input. More inner cavities were found near the interface of the fusion zone and sintered segment and in the bottom of the fusion zone. Inner cavity was mainly formed in the upper fusion zone at high heat input whereas was in the bottom at low heat input. Inner cavity was from trapping of coarsened preexist pores in the sintered tip and metal vapor due to rapid solidification of molten metal before the bubbles escaped.

• Journal of Chest Surgery
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• 제12권1호
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• pp.61-66
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• 1979

This is a report of a case of tuberculous esophageal perforation, which was surgically treated.. The patient was 32-year-old Korean female patient, who complained swallowing difficulty for` 4 weeks duration. Esophagogram was shown irregular filling defects in the upper one third of esophagus, about 4 cm in length. It was noticed that a small amount of contrast media was leaked out from the involved area of esophagus into the right mediastinum. It was highly suggested that abscess formation was due to perforation of esophageal cancer. Esophagoscopy revealed no definitive evidence of perforation of esophagus, but punch biopsy specimen of esophageal mucosa was shown acute and chronic inflammatory changes. Operation was performed under impression of esophageal cancer. In the right-sided upper mediastinum, a walnut-sized abscess cavity which was connected with esophagus through a fistulous tract was noted. A portion of cavity submitted for frozen section was shown tuberculous inflammation. The abscess cavity, fistula tract, and involved esophageal wall were removed. The perforated esophagus was closed layer by layer. The tuberculous changes were confirmed by histopathologic examination postoperatively. The postoperative course was uneventful.

• Journal of Yeungnam Medical Science
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• 제6권2호
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• pp.279-285
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• 1989

Inverted papilloma arising from mucous membrane of the nasal cavity and paranasal sinuses is rare benign neoplasm, and usually unilateral arise from lateral wall of nasal cavity. This tumor is histologically benign neoplasm but clinically malignant, because of frequent recurrence and extensive bone destruction. And occasionally, this tumor can be transformed to squamous cell carcinoma or verrucous carcinoma. Recently, We have experienced a case of the inverted papilloma with verrucous carcinoma of the nose and paranasal sinuses and patient expired due to extension of intracranial cavity. We report our case with review of current literatures.