• Journal of Chest Surgery
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• v.37 no.10
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• pp.884-887
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• 2004

We applied our technique of selective bronchial suctioning (SBS) for the treatment of atelectasis after resection surgery of lung in four patients with refractory atelectasis who were treated successfully. We considered that SBS using hydro-catheter insertion under local anesthesia above fourth tracheal ring is the effective technique for the treatment of refractory atelectasis when conventional respiratory therapy is not effective and a bronchoscopist is not available.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.4
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• pp.589-594
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• 1999

There are some problems in inhalation sedation of non-cooperative pediatric patients. Usually the pediatric patients reject the nasal hood and there's no cooperation for administration of nitrous oxide gas. In mouth breathing patient, other technics of sedation such as intravenous or oral sedation or general anesthesia were recommended. Common causes of mouth breathing are common cold, allergic rhinitis, sinus problem, anatomical disorder, and habitual mouth-breathing. However in some patient not indicated the general anesthesia and high failure rate in oral and intravenous sedation. Administration of $N_2O-O_2$ with suction catheter was applied in full mouth breathing patient. Clinically effective sedation were occurred during procedure about 45 to 55 minutes. There's no any side effects by $N_2O-O_2$ inhalation sedation. The patients awoke at the end of the procedure and received 100% oxygen for 2-3 minutes. There's still some problems in use of the suction catheter such as air pollution of operation theater and elevate arterial carbon dioxide tension.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.15-23
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• 2004

In order to investigate efficiency and flowfield charateristics of the intake-diffuser for the ship waterjet propulsion, new experimental verification technology was set up in the cavitation tunnel. 1-hole and 5-hole pilot tubes were designed and manufactured to measure the pressure and velocity distributions at intake-diffuser entrance and impeller inlet. The calibration of the 5-hole pilot tubes is conducted at the cavitation tunnel The cavitation inception occurs at the intake lip, and the occurrence position depends on IVR (Inlet Velocity Ratio) condition. The present experimental device will be applied sufficiently for the development of the design and performance improvement technologies.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.1
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• pp.12-19
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• 2022

The exhaust wake of an aircraft engine is discharged in a high temperature and high speed, which can damage objects such as an aircraft in the rear. The exhaust wake can lift small foreign substances lying on the ground or falling off, and the floating foreign substances can enter the intake duct of the aircraft moving from the rear and cause engine FOD (Foreign Object Damage). This study experimentally analyzed how the engine exhaust wake generated from military jet fighters affects the movement of foreign substances and evaluated the effects of foreign substances on the damaged area by measuring wake velocity. The simulation and field experimental results confirmed that the effect of exhaust wake increases as the rear position closer, and that foreign substances lifted by the wake can act as FOD to the adjacent rear aircraft.

• Tuberculosis and Respiratory Diseases
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• v.43 no.3
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• pp.410-419
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• 1996

Background : Spontaneous pneumothorax have been managed with a variety of methods. The technique most frequently used is chest tube drainage. Small caliber catheters were first used in the management of pneumothorax complicating the percutaneous needle aspiration lung biopsy, and the try to treat spontaneous pneumothorax also has been reported. However, the value of small caliber catheters in spontaneous pneumothorax has not been fully evaluated. So, we tried to elucidate the efficacy of 8 French catheter in the management of spontaneous pneumothorax. Method : From January, 1990, to April, 1994, 44 patients with spontaneous pneumothorax treated at Chung-Ang university hospital were reviewed. The patients were sub-divide into 8 French catheter insertion group (n=21) and chest tube insertion group (n=23). We compared the presence of underlying lung disease, the extent of the collapse, the duration of indwelling catheter and complication between two groups. Results : 1) The duration of indwelling showed no significant difference between 8 French catheter group and chest tube. But, complication after insertion as subcutaneous emphysema was developed in only chest tube group. (p<0.05) 2) In the primary spontaneous pneumothorax, all case of the pneumothorax of which size was less than 50% showed complete healing with 8 French catheter insertion. Whereas the success rate in patients with large pneumothorax (more than 50%) was tended to be dependent on the age. 3) In the patients with secondary spontaneous pneumothorax who were managed with 8 French catheter, the success rate was trended to be high if the underlying disease of pneumothorax was not COPD and if the patient was young. Conclusion : These results show that 8 French catheter insertion probably was effective in the pneumothorax less than 50%, the primary spontaneous pneumothorax, young age or secondary pneumothorax not associated with COPD.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.24-24
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• 2002

가스터빈 엔진의 공력 성능은 작동 유체인 공기의 물성 변화에 대하여 민감하게 반응하는데, 대기 중에 수증기 형태로 함유되어 있는 수분이 공기의 물성 변화를 야기하는 대표적인 요인이다. 건공기와는 다른 화학적 조성을 가지는 습한 공기가 가스터빈 엔진에 유입되면 엔진의 작동과 성능에 2가지 방법(공기 흡입 도관에서의 응축 그리고 엔진 전체 사이클에 걸친 가스 조성 변화 야기)으로 영향을 미친다. 절대 습도가 높은 지상 조건의 무더운 날에는 습공기 유입으로 인한 가스터빈 엔진의 성능 저하가 두드러지며 지상에서의 고공환경시험에서는 시험 당일의 습도 조건에 따라 성능의 차이를 보인다. 해상에서 운용되는 비행체 추진기관으로 사용되는 가스터빈의 경우 특히 높은 습도 환경에서 작동하므로 습도 보정을 통하여 엔진의 정확한 성능과 운용성을 파악하는 것은 중요하다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.744-745
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• 2008

IT기기, 통신시기, 반도체 기기 등은 점점 더 고성능화되면서 속도도 빨라지고 기능도 추가되는 추세이다. 이러한 IT기기들은 속도와 더불어 열문제는 더욱더 크게 강조되고 있는 실정이며 개인용으로 많이 사용하고 있는 PC의 경우 더 이상 속도를 높이지 못하고 있는 실정이다. 이러한 열문제는 100W까지는 Heat pipe 등으로 냉각이 가능하였으나 거의 한계수준에 도달한 상황이다. 이러한 상황에서 일부 메니아들은 빠른 속도의 통신이나 작업을 위해서 수냉식 전용 냉각기를 설치하여 현재의 기능보다 더 좋은 환경에서 사용하고자 하고 있다. 본 연구에서는 수냉식 냉각기보다 더 큰 열용량을 가진 CPU의 냉각을 위해서 냉매 압축기를 적용하고자 하였으며 냉매 압축기에 사용하기 위한 선형압축기를 개발하고자 하였다. 즉 선형압축기에 의해서 압축된 냉매를 사용하여 CPU를 냉각하기 위해서 본 연구를 시작하였다. 본 연구에서는 선형전동기를 공진구동형 스프링을 장착하여 50-100Hz로 공진구동하는 액추에이터를 제작하여 그 특성을 알아보았다. 먼저 제자과정과 제작후 추력과 공진구동 설계 및 공진구동시 전기적, 기계적 특성변화를 확인하였으며 피스톤과 실린더 및 흡입밸브와 배기밸브 등을 장착하여 선형압축기로서 시운전까지 수행하였다.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.2
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• pp.228-234
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• 2017

Hydrocephalus is a condition in which the volume of cerebrospinal fluid in the cerebral ventricles is abnormally elevated. Hydrocephalus patients may show macrocephaly and delayed development. Ventriculoperitoneal shunt is the most commonly used treatment but ventriculoatrial shunt is another treatment option. This report discusses the dental management process employed for a 7-year, 6-month old patient with ventriculoperitoneal shunt-treated hydrocephalus. This patient showed dental caries on the deciduous molars, facial swelling, macrocephaly and delayed development. Pulpectomy was performed on the deciduous molars under nitrous oxide sedation and mild protective stabilization. This patient did not appear to have any specific complications until the latest follow-up and was scheduled for the management of overall oral hygiene, development of permanent teeth, and craniofacial asymmetry through periodic follow-up. During dental treatment of shunt-treated patients, care should be taken to avoid applying excessive force to the catheter running along the patient's neck to prevent the displacement of the catheter. A referral to a neurosurgeon is recommended for patients with ventriculoatrial shunts for prophylactic antibiotics. As hydrocephalus patients grow, they may show craniofacial asymmetry or differences in the calcification of the permanent teeth, and require periodic oral and craniofacial assessment.

• Neonatal Medicine
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• v.17 no.1
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• pp.109-115
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• 2010

Persistent pulmonary hypertension in newborns (PPHN) is a disorder of the vascular transition from fetal to neonatal circulation. It results in cyanosis due to right-to-left shunting of the blood through the ductus arteriosus and/or foramen ovale manifesting as hypoxemic respiratory failure. We managed two cases of PPHN after meconium aspiration with high frequency oscillating ventilators and inhaled nitric oxide. They did not respond to conventional management. Veno-venous extracorporeal membrane oxygenation (ECMO) was provided, and ECMO weaning was possible resulting survivals in two cases. We report two PPHN cases, which were treated successfully with veno-venous ECMO for the first time in Korea.

• Tuberculosis and Respiratory Diseases
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• v.56 no.6
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• pp.670-676
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• 2004

Chemical pneumonitis is caused by the inhalation of noxious chemical substances and is a cause of occupational lung disease. Nitric acid, which is a one of the common air pollutants and a potential oxidant for refining and cleansing of metals, has a chance for occupational and environmental exposure. A 52-year-old man visited our hospital due to coughing and dyspnea after the inhalation of nitric acid fumes at his workplace. He had conditions of tachypnea (respiratory rate 26 /min) and hypoxemia ($PaO_2$ 42.6 mmHg, $SaO_2$ 80.2% in room air) in our emergency department. The chest radiographs showed diffuse interstitial infiltrates and ground glass opacity in both lungs. The patient made improvements in clinical symptoms and chest radiography after being given a supply of oxygen, antibiotics, and bronchodilator therapy without systemic glucocorticoid therapy. On his follow up visit after 4 weeks, he showed no symptoms and sequelae, and the pulmonary function test showed a normal pulmonary function.