• Journal of Chest Surgery
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• v.32 no.2
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• pp.189-193
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• 1999

Mesenchymal cystic hamartoma of the lung is quite rare lesion which has an unknown prevalence, firstly described in 1986. It is characterized by multiple nodules and variable sized cysts in both lung field. The nodules of immature mesenchymal cells gradually enlarge and become cysts which are lined with normal or metaplastic respiratory epithelium and have the cambium layer of primitive mesenchymal cells. Main symptoms are hemoptysis, recurrent pneumothorax, and hemothorax. It is known to benign tumor, but has possibility of malignant degeneration. In gross findings in opertive field, multiple and variable-sized cystic lesions and nodules were observed. The cysts were lined with normal respiratory epithelium and had the cambium layer of primitive mesenchymal cell. Gross and microscopic findings were compatible with mesenchymal cystic hamartoma. We report a case of mesenchymal cystic hamartoma in a 27-year-old woman who had recurrent pneumothorax and hemoptysis.

• Journal of Biomedical Engineering Research
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• v.22 no.6
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• pp.503-510
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• 2001

In this paper. we describe a 32-channel bioimpedance measurement system It consists of 32 independent constant current sources of 50 kHz sinusoid. The amplitude of each current source can be adjusted using a 12-bit MDAC. After we applied a pattern of injection currents through 32 current injection electrodes. we measured induced boundary voltages using a variable-gain narrow-band instrumentation amplifier. a Phase-sensitive demodulator. and a 12-bit ADC. The system is interfaced to a PC for the control and data acquisition. We used the system to detect anomalies with different resistivity values in a saline Phantom with 290mm diameter The accuracy of the developed system was estimated as 2.42% and we found that anomalies larger than 8mm in diameter can be detected. We Plan to improve the accuracy by using a digital oscillator improved current sources by feedback control, Phase-sensitive A/D conversion. etc. to detect anomalies smaller than 1mm in diameter.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.554-560
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• 2003

Purpose : To investigate the teratogenic effect of gamma-ray on the heart of chick embryo. Methods : 50 rad, 100 rad, 150 rad, 200 rad, 250 rad, and 300 rad of gamma-ray were used to irradiate three days old chick embryos. The control group was not irradiated. After three weeks, the embryos were sacrificed and examined for cardiovascular malformation. Results : The survival rate of the gamma-ray irradiated group was significantly lower than that of the control group(33.3-63.3% vs 76.4%, P=0.001). The cardiac malformation rate of the experimental group was 11.0%. In the control group, no congenital cardiac malformations were observed. The experimental groups had a significantly higher malformation rate(P=0.001). The types of malformation were ventricular septal defect, tricuspid atresia, Ebstein anomaly and aortic arch anomaly. In the gamma-ray irradiated group, the cardiac malformations were : 14 small ventricular septal defects (VSDs), five large VSDs, two tricuspid atresias, and one Ebstein anomaly. The higher the dose of radiation applied, the higher the incidence of cardiac malformation was noted. Conclusion : Gamma-ray irradiation of 3 days old chick embryos increased the rate of death and the rate of cardiac malformation significantly.

• Journal of Chest Surgery
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• v.31 no.6
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• pp.634-637
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• 1998

An unusual placentoid bullous lesion of the lung was reported. The patient was a 27-year- old woman with a 1-week history of chest pain and mild dyspnea. Chest radiographic studies showed multiple huge bullae in right upper lobe and variable-sized bullae in middle and lower lobes with collapse. She underwent right pneumonectomy with preoperative impression of bullous lung disease and emphysema. Histopathologically, the most distinctive features were villous structures within bullous airspace, which resembled placetal villi with degeneration.

• Journal of Chest Surgery
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• v.36 no.3
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• pp.206-210
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• 2003

Hemangiomas in the esophagus comprise less than 3% of all benign esophageal neoplasms. They are frequently small and easily treated with resection via either endoscopy or thoracotomy. We report a cavernous hemangioma occurred in the distal esophagus successfully treated with circumferential myomectomy.

• Journal of Chest Surgery
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• v.37 no.9
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• pp.813-816
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• 2004

The conformation of traumatic diaphragmatic rupture is frequently difficult, even if radiologic evaluation has been performed. A 37-year old man with multiple trauma was suspicious with diaphragmatic rupture. The diaphragmatic rupture could not be confirmed with chest CT. We decided thoracoscopic operation for diagnosis. Diaphragm was ruptured about 8 cm length involving entering site of phrenic none into diaphragm and diaphragmatic paralysis was combined. We made 5 cm sized working window additionally. Ruptured diaphragm was repaired by continuous suture and plication of diaphragm was performed. Postoperative result was good at chest radiogram after three monthes.

• Journal of Chest Surgery
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• v.35 no.1
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• pp.82-85
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• 2002

Cavernous hemangiomas of the mediastinum are rare tumors. A 3 year and 8 month-old female patient was referred because of an abnormal chest radiograph. Chest X-ray revealed abnormal shadow occupying nearly the entire left thoracic cavity Surgical excision was performed and pathologic diagnosis was confirmed as 15 $\times$ 10 cm sized cavernous hemangioma. On the eighth postoperative day, the patient was discharged without any complications and has been followed up without any problems.

• Journal of the Korean Professional Engineers Association
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• v.31 no.1
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• pp.17-28
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• 1998

누설 검출기들 중에서 검출 감도가 가장 민감한 것은 '헬륨 양이온 질량 분석계 누설 검출기(줄인 이름, '헬륨 누설검출기')'이다. 이 글은 헬륨 누설 검출기의 주요 부분을 이루고 있는 질량 분석계의 측정 원리를 요약하여 소개한 것이다. 누설 검사의 항목들은 검사의 필요에 따라 대개 시험 물체에서 누설의 크기와 시험 방법을 바탕으로 하여 대규모 누설, 총량 누설, 소규모 누설 그리고 미세 누설 등으로 나뉘어지며, 미세 누설들은 누설 검출기의 최소 검출 가능 누출률이 $10^{-8}$ std ㎤ s$^{-1}$ 보다 작은 범위에 있는 것들로서, 그들의 누설 시험은 헬륨 누설 검출기를 써서 하게 된다. 따라서, 헬륨 누설 검출기의 심장은 바로 질량 분석계이며, 질량 분석계의 원리를 이해하는 것은 곧, 헬륨 누설 검출기를 다루는 기술의 바탕을 다지는 것이라고 말할 수 있을 것이다. 여기서는 헬륨 질량 분석계의 원리를 쉽게 풀이하고, 그런 검출기를 써서 누설검사를 하는 데 바탕이 될 모습들을 함께 요약한다.약한다.

• Journal of Power System Engineering
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• v.11 no.2
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• pp.38-43
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• 2007

전자기적으로 지지되는 임펠러를 가진 원심 혈액 펌프는 기존의 심장 펌프에 비해 많은 장점을 가지고 있지만, BVAD의 틈새에서 발생하는 유체 동역학적인 문제는 여전히 규명이 되지 않은 상태이다. 본 연구에서는 BVAD의 틈새에서 발생하는 혈액외상(blood trauma)의 예측에 대한 연구에 중점을 두고 있다. 일반적으로 원심 혈액 펌프의 설계를 위해 전자기적으로 지지되는 원심 혈액 펌프의 디스크 틈새에서 발생하는 혈액의 손상을 평가하는 방법으로 CFD를 이용한 방법이 널리 이용되고 있다. 따라서, 본 연구에서는 초기 원심 혈액 펌프의 설계 단계에서 펌프의 특성을 평가하기 위하여, 축 방향 틈새의 영향과 회전수 변화에 따른 누수경로의 전단 응력의 크기 평가를 CFD를 사용하여 해석하여 보았다.

• Journal of Chest Surgery
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• v.34 no.1
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• pp.91-93
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• 2001

기계판막의 비구조적 기능이상은 판막 치환 후 생길 수 있는 심각한 합병증 중의 하나이다. 이러한 기계판막의 비구조적 기능이상은 일반적으로 1) pannus나 조직 혹은 봉합물질에 의한 장애 2) 치환 판막 주위의 틈 3) 부적절한 판막의 크기나 위치, 판막 삽입시의 잘못 등에 의해 생긴다. 저자들은 상대적으로 작은 판막륜을 가진 환자에서 치환 판막의 잘못된 위치로 야기된 pannus 형성에 의한 판막의 기능부전을 경험하였으며, 이 환자에 대해 pannus 제거 후 판막륜 확장술(닉스 술식, Nicks procedure)을 포함한 판막 재치환술을 성공적으로 시행하여 이를 보고하는 바이다.