• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권5호
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• pp.315-320
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• 2000

This paper presents the fabrication and test of a micropump with an electromagnetic actuator and a pair of aluminum flap valves. The actuator consists of a solenoid coil, a permanent magnet and an actuator diaphragm. The actuator diaphragm is fabricated by the spin coating of silicone rubber. The valve are passive ones and are fabricated by micromachining. The deflection of the fabricated actuator diaphragm is measured with a laser vibrometer. The deflection of the actuator diaphragm is proportional to the input current. The measured deflection of the fabricated diaphragm is $400 \mum$,/TEX> when the input is 118 mApp, and the cut-off frequency is 50 Hz. The maximum flow rate of the fabricated micropump with the electromagnetic actuator is about 5$0 \muell/min$ at 5 Hz when the input current and the duty ratio of the square was are 118 mApp and 50%, respectively.

• Journal of Chest Surgery
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• 제17권3호
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• pp.448-455
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• 1984

Coarctation of the Aorta is a congenital constriction of aorta of varying degree, usually located at or near the aortic ismuth with frequent associations of other cardiac anomalies. Various modes of surgical corrections, such as resection and end-to-end anastomosis, graft interposition, angioplasty using prosthetic patch or subclavian flap have been used according to the status of coarctation and age of the patient. We have experienced two cases of surgically treated coarctation of the aorta, one of which was preductal coarctation with hypoplastic aortic arch and ventricular septal defect in a 4 year old boy, and the other case was juxtaductal type with aortic regurgitation. Subclavian flap angioplasty with additional pulmonary artery banding procedure was done in the first case and wedge resection with end-to-end anastomosis and aortic valve replacement [St. Jude valve, 23mm] 20 days later of first operation in the other case. The first case developed massive tarry stool on 3rd POD, probably due to mesenteric arteritis with resultant bowl ecrosis, and expired the next day. Recovery was uneventful with the second case.

• Journal of Chest Surgery
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• 제26권8호
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• pp.604-608
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• 1993

Coarctation of aorta is rather common congenital cardiovascular disease in the western contries, but it is known to be less than 2 % in Korea. From June 1986 to December 1992, seven patients of surgically treated coarctation of aorta who were less than 2 years old, were experienced at Department of Thoracic and Cardiovascular Surgery, Yeungnam University Hospital. The patients included six male and one female, with ages in the range of one month and 24 months. Four patients were preductal type and three juxtaductal. Associated cardiac anomalies were present in all patients and they were PDA[6 cases], ASD[3], VSD[2], bicuspid aortic valve[2], aortic stenosis[1], mitral regurgitation[1], and tricuspid regurgitation[1]. The operative procedures were four end to end anastomosis and three subclavian flap aortoplasty. Mean aortic cross clamping times were 37.3 minutes in patients with end to end anastomosis and 30.3 minutes in patients with subclavian flap aortoplasty. There were two operative deaths in patients who were treated with subclavian flap aortoplasty and pulmonary artery banding. One patient who had been treated with subclavian flap aortoplasty was complicated with postoperative mild paraplegia in lower limb. Pulmonary artery banding has been disappointing in our patients, and the data was suggestive that earlier total repair of complicated coarctation might improve survival.

• Archives of Plastic Surgery
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• 제49권3호
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• pp.378-396
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• 2022

Several reconstructive methods have been reported to restore the continuity of the aerodigestive tract following resection of pharyngeal and hypopharyngeal cancers. However, high complication rates have been reported after voice prosthesis insertion. In this setting, the ileocolon free flap (ICFF) offers a tubularized flap for reconstruction of the hypopharynx while providing a natural phonation tube. Herein, we systematically reviewed the current evidence on the use of the ICFF for reconstruction of the aerodigestive tract. A systematic literature search was conducted across PubMed MEDLINE, Web of Science, ScienceDirect, Scopus, and Ovid MEDLINE(R). Data on the technical considerations and surgical and functional outcomes were extracted. Twenty-one studies were included. The mean age and follow-up were 54.65 years and 24.72 months, respectively. An isoperistaltic or antiperistaltic standard ICFF, patch flap, or chimeric seromuscular-ICFF can be used depending on the patients' needs. The seromuscular chimeric flap is useful to augment the closure of the distal anastomotic site. The maximum phonation time, frequency, and sound pressure level (dB) were higher with ileal segments of 7 to 15 cm. The incidence of postoperative leakage ranged from 0 to 13.3%, and the majority was occurring at the coloesophageal junction. The revision rate of the microanastomosis ranged from 0 to 16.6%. The ICFF provides a reliable and versatile alternative for reconstruction of middle-size defects of the aerodigestive tract. Its three-dimensional configuration and functional anatomy encourage early speech and deglutition without a prosthetic valve and minimal donor-site morbidity.

• 설비공학논문집
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• 제19권5호
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• pp.411-417
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• 2007

This study has been conducted to investigate pumping characteristics of diffuser/nozzle based piezoelectric micropumps. The micropumps include a piezo disk (an actuator), a chamber and a set of diffuser and nozzle. Flow in the current micropumps is controlled by a set of diffuser and nozzle, not by a nap valve. The diffuser/nozzle based micropumps are more reliable in operation and are easier in manufacturing than the flap valve based micropumps. The flow rates of the piezoelectric micropumps have been closely analyzed with a numerical calculation. It has been found that the positions of the inlet and outlet of the micropump can influence the performance of the diffuser/nozzle based piezoelectric micropumps. This study may provide fundamental understanding for the design and analysis of the piezoelectric micropumps.

• Journal of Chest Surgery
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• 제34권11호
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• pp.848-853
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• 2001

배경 및 목적: 정중 흉골 절개 후 발생한 흉골 감염과 열개(dehiscence)는 드물지만 적절한 치료를 하지 않을 경우 그 사망률은 높다. 본 교실은 개심술 후 발생한 12예의 흉골 감염 및 열개 환자에서 광범위한 괴사조직 제거와 근육편 이식술로 치료하고 그 수술 결과를 보호하고 효과적인 치료 방법을 찾고자 하였다. 대상 및 방법: 개심술 후 흉골 감염과 열개가 발생한 13예 중 흉골감염의 치료 전에 뇌경색으로 사망했던 1예를 제외하고 12예를 치료대상으로 하였다. 6예가 판막치환술 환자였고, 다른 6예가 관상동맥우회로술 환자였다. 1991년 이후에 수술한 7예에서는 짧은 기간의 배액(배농)과 세척으로 발열이 없어지면 바로 수술하였다. 감염 및 괴사된 연부조직 및 뼈를 절제하고 흉골의 사장을 우측 대흉근편 (회전편), 좌측 대흉근편 (회전편 또는 전진편), 우복직근을 단독 또는 복합으로 보강하였다. 결과: 12예의 흉골 감염 및 별개의 수술 치료 후 사망은 없었다 흉골 감염 및 열개가 발견된 후 평균 6.6$\pm$3.9일에 근육편의 이식수술을 하였다. 4예에서 우측 대흉근편을, 8예에서 양측 대흉근편을 사용하였으며, 각각 1예와 2예에서는 우복직근도 사용하였다. 1예에서 좌측 대흉근의 전진편이 괴사되고 흉벽농양이 발생하여 우복직근을 이용하여 재수술하였다. 근래에 수술한 3예에서는 우측 대흉근의 전진편만을 넓게 펴서 흉골사강을 보강하여 한 근육 편으로 흉골열개를 치료하였으며 3주 이상 개방성 배액관의 거치가 필요했다. 결론: 개심술 후 합병된 흉골절개부위의 열개 및 감염에서 짧은 기간의 세척 후 조기 수술에 의한 괴사조직의 제거와 주위 근육편 이식으로 쉽게 치료할 수 있으며, 우측의 대흉근만으로도 흉골 열개의 수술치료가 가능하다고 생각된다.

• Archives of Plastic Surgery
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• 제39권1호
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• pp.25-30
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• 2012

Background : The soft palate functions as a valve and helps generate the oral pressure required for normal speech resonance. Speech problems and nasal regurgitation can result from a soft palatal defect. Reduction of the size of the velopharyngeal orifice is required to compensate for the lack of mobility in a reconstructed soft palate. We suggest a large volume folded free flap for reduction of the caliber and a palmaris longus tendon sling for suspension of the reconstructed palate. Methods : Six patients had total soft palate resection for tonsillar cancer and reconstruction with a large volume folded radial forearm free flap combined with a palmaris longus sling. A single surgeon and speech therapist examined the patients with three standardized speech assessment tools: nasometer test, consonant articulation test, and speech acuity test performed for speech evaluation. Results : Mean nasalance score was 76.20% for sentences with nasal sounds and 43.60% for sentences with oral sounds. Hypernasality was seen for oral sound sentences. The mean score of the picture consonant articulation test was 84% (range, 63% to 100%). The mean score of the speech acuity test was 5.84 (range, 5 to 6). These mean ratings represent a satisfactory level of speech function. Conclusions : The large volume folded free flap with a palmaris longus tendon sling for total soft palate reconstruction resulted in satisfactory prognosis for speech despite moderate hypernasality.

• 한국항공우주학회지
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• 제35권4호
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• pp.302-307
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• 2007

본 연구에서는 이온성 폴리머-금속 복합재료 (IPMC) 작동기를 사용한 플랩 밸브 마이크로 펌프의 설계, 제작 및 실험적 특성 규명을 수행하였다. 나피온/실리케이트 층과 나피온/실리카 나노복합재료를 기반으로 한 다층형 IPMC를 마이크로 펌프의 작동층으로 사용하였다. 마이크로 펌프의 핵심 요소인 IPMC 다이아프램의 주위를 유연한 폴리디메틸실옥산(PDMS)을 사용하여 지지하도록 함으로써 상당히 큰 작동 변위를 내도록 설계하였다. 이렇게 개발된 마이크로 펌프의 크기는 $20{\times}20{\times}5$ ${mm}^3$ 이고, 최대 유량은 760 l/min, 최대 배압은 1.5 kPa이었다. 본 연구에서 개발한 마이크로 펌프는 간단하고 효율적인 설계를 수행하여 제작이 용이할 뿐 아니라, 동작 전압이 1-3V라는 장점이 있다.

• 대한임상검사과학회지
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• 제52권4호
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• pp.425-429
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• 2020

대동맥박리(aortic dissection)란 대동맥 내막에 미세한 파열이 발생하면 높은 대동맥 압력으로 인해 대동맥의 중막이 장축으로 찢어지면서 대동맥이 진성 내강(true lumen)과 가성 내강(false lumen)으로 분리되는 것을 말하며 사망률이 아주 높은 질환으로 빈도를 보면 남자가 여자보다 2~5배 정도 많이 발생하고, 호발하는 연령대는 50~70세 사이로 알려져 있다. 본 증례에서는 자주 발생되지 않는 젊은 30대 여자에게서 발생된 대동맥 박리증 진단을 직접 경험하였던 바 중증 대동맥판 역류증(severe aortic regurgitation)을 추적하는 과정에서 처음에는 대동맥판 탈출증(aortic valve prolapse)을 의심하였다. 이 의심된 부분을 확인하는 과정에서 상행대동맥의 내막피판 관찰을 통해 대동맥 박리증을 진단할 수 있었기에 이를 보고하는 바이다.

• 한국가스학회지
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• 제22권2호
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• pp.78-83
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• 2018

이 논문은 디젤엔진 자동차의 EGR 및 공기 제어와 CPF 장치에 관련된 고장사례 연구이다. 첫 번째 사례는 엔진진공펌프 손상으로 인해 엔진오일이 EGR 밸브 내부 다이어프램 손상으로 인해 오일이 흡기로 유입되어 연소실로 들어가 불완전 연소함으로써 배기할 때 매연이 발생된 것으로 확인되었다. 두 번째 사례의 원인은 공기제어 장치인 스로틀 플랩(throttle flap)을 점검하였을 때 스로틀 플랩이 고착되어 흡입공기량 부족에 의해 매연이 발생된 것을 확인하였다. 세 번째 사례는, 배기가스 온도센서의 불량으로 인해 온도를 감지하지 못해 재생기능이 되지 않아 매연이 발생된 것으로 확인되었다. 따라서, 배기가스발생으로 인한 환경오염 문제가 발생하지 않도록 최적의 상태를 유지하도록 관리하여야 한다.