• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.67-67
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• 1995

Metal-working lubricants, metal-finishing bath wastes, mechanical oil-water emlsion 등과 같은 공업 폐수들은 보통 0.1 $\mu$m 이하의 크기를 가지는 oil-in-water 에멀젼이 약 2 wt% 정도 포함되어 있어, oil의 함량이 30 wt% 이상이 되도록 농축시킨다면 재사용이 가능하게 되며, 정밀여과막이나 한외여과막으로 oil을 분리할 수 있다. 본 실험에서는 압출성형법으로 제조한 튜브형 다공성 $\alpha-Al_2O_3$ 담체(평균 기공 크기 = 0.7 $\mu$m, 길이:200,600mm, 직경:8mm, 두께:0.8mm) 위에 슬립 캐스팅법을 이용하여 TiO$_2$ 막을 코팅한 후 925$\circ$C에서 2시간 동안 열처리하여 정밀여과용 세라믹 막을 제조하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.128-129
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• 2007

Cr-Al-N, Cr-Si-N 그리고 Cr-Al-Si-N 코팅막을 WC-Co 모재위에 AIP법과 DC 마그네트론 스퍼터링 법을 결합한 하이브리드 시스템을 이용하여 합성하였으며, Si함량에 따른 Cr-Al-Si-N 코팅막의 미세구조, 기계적 특성과 마찰 거동에 관해 비교 연구하였다. Cr-Si-N(${\sim}35GPa$)과 Cr-Al-Si-N(${\sim}55GPa$) 코팅막의 경도값은 CrN(${\sim}23GPa$)과 Cr-Al-N(${\sim}25GPa$) 코팅막과 비교하여 각각 증가하였고, CrN(${\sim}0.50$)과 Cr-Al-N(${\sim}0.84$)의 평균 마찰계수는 Si 함량이 9 at.% 일때, Cr-Si-N(${\sim}0.30$)과 Cr-Al-Si-N(${\sim}0.57$)으로 각각 감소하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.120-122
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• 2007

3성분계 $Ti-C_x-N_{1-x}$ 코팅막은 AIP(Arc Ion Plating)법에 의해 -25V의 바이어스와 $300^{\circ}C$의 분위기에서 스테인리스 스틸 기판 위에 증착시켰다. $Ti-C_x-N_{1-x}$ 코팅막 안의 탄소(carbon)는 유입가스 비 $CH_4/(CH_4+N_2)$를 변화시키며 합성하였다. 탄소(carbon)가 증가함으로써, $Ti-C_x-N_{1-x}$ 코팅막의 미세경도는 TiN 코팅막의 20 GPa로부터 x=0.52에서 최대 약 32 GPa로 측정되었다. 또한, 미세구조는 잔류응력과 관련 있으며 탄소 함량에 따라 평균마찰계수가 크게 감소하였다.

• Membrane Journal
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• v.8 no.2
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• pp.102-108
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• 1998

Permeation behavior of the semiconductor rinsing wastewater containing Si particles was examined by ultrafiltration using the polysulfone plate membrane. The permeation flux was gradually decreased with time. It was due to the growth of cake deposited on the membrane surface and the pore plugging by Si particles. Permeation flux of cross flow type was 1.4 times higher than that of the dead end flow type. Nitrogen back flushing which is the removing method of membrane fouling was superior to the water sweeping. With nitrogen back flushing, the decrease of permeation flux due to the fouling was recovered about 85 % to the initial flux in the flat plate membrane system. The rejection rate of Si particles was about 90 % and the size of Si particle in the permeate was about 70 nm.

• Applied Microscopy
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• v.16 no.2
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• pp.25-34
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• 1986

The endocrine cells of the stomach and duodenum of the pond tortoise (Amyda sinensis) have been studied by electron microscopy. At least six types of endocrine cells could be identified in these regions. Type I cells were characterized by having pleomorphic or medium sized granules ($100{\sim}430nm$ in diameter, mean; 290 nm) which were moderate in electron density. Type II cells were characterized by having pleomorphic or medium sized granules ($190{\sim}430nm$ in diameter, mean; 280 nm) which were high in electron density. Type III cells were characterized by having large oval or irregular granules($170{\sim}650nm$, mean: 430 nm) with wide vesicular halo which were high in electron density. Type IV cells were characterized by having round or medium sized granules($140{\sim}370nm$, mean; 240 nm) which were low to moderate in electron density and showed a very thin halo. Type V cells were characterized by having large round or oval granules($300{\sim}600nm$, mean; 410 nm) which were low to moderate in electron density and showed a dense core and a wide clear halo. Microfilaments were also found in the cytoplasm. Type VI cells were characterized by having round and small granules($100{\sim}220nm$, mean; 160 nm) which were low to moderate in electron density and showed a very thin halo or crystalline structure of the contents. Many microfilament bundles were also found in the cytoplasm.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.812-816
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• 2002

Pericardial effusions result from various conditions such as inflammation, malignancies, open heart surgery and uremia. Recently, video assisted thoracic surgery (VATS) has been used for diagnostic and therapeutic purposes in the management of pericardial effusion and intrathoracic lesions due to its ability to provide outstanding visibility of intrathoracic structures with less pain, superior cosmetic effects, and shorter hospital stay Material and Method: From April 1995 to October 2001, 51 patients received pericardial window operation via either thoracoscopic(Group A, n＝37, m:f＝18:19, mean age＝56.4 yrs)or thoracotomy approach(Group B, n＝14, m:f＝8:6, mean age=58.4 yrs). Result: In group A, the operation time, duration of chest tube insertion, recurrence rate of pericardial effusion, and postoperative hospital stay were 61.2 minutes, 9.3 days, 2.7%, 16.2 days, respectively while in group B these values were 58.4 minutes, 12.2 days, 7.1, and 17.3 days. The number of injections for pain control in group A were 4.2 times, whereas in group B it was 6.3 times. Although there was a tendency for the mean hospital stay and duration of chest tube insertion to be shorter in group A than in group B, these differences did not reach statistical significance. There was also no significant difference in the operation time and recurrence rate between the two groups. Conclusion: The safety and effectiveness of VATS in the management of pericardial effusion is comparable to the open thoracotomy method. It allows for a shorter hospital stay, duration of chest tube insertion, lesser postoperative pain and a smaller skin incision.

• Research in Plant Disease
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• v.10 no.3
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• pp.175-182
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• 2004

Teliospores of two species of Gymnosporangium asiaticum and G.yamadae collected and identified from Juniperus chinensis, J.chinensis L.var.kaizuka. G.asiaticum was identified as the thick membraned (cell-walled) teliospores (avr 2.5 ${\mu}{\textrm}{m}$) and thin membraned teliospores (avr 1.2 ${\mu}{\textrm}{m}$), and the telia of G.asiaticum was bluntly conical shaped and occured on the leaves and branches of Chinese junipers. G.yamadae was identified as the thick membraned (cell-walled) teliospores (avr 2.5 ${\mu}{\textrm}{m}$) and thin membraned teliospores (avr 1.2 ${\mu}{\textrm}{m}$), and the telia of G. yamadae was gall or floral shaped and occured on the leaves and branches of Chinese junipers. Both of the telia of the two species of Gymnosporangium were occurred in a same tree of Juniperus chinensis L. var. kaizuka at the same time. But the dominant species is G. asiaticum. The more rainfall in the late of April (the season of forming basidiospore), the more rust diseases in Chaenomeles sinensis. C. sinensis, and Pyrus pyrifolia var. culta were infected by G. asiaticum (basidiospores) but Malus siebodii was not infected by G.asiaticum.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.221-225
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• 1998

From February 1996 to May 1997, 18 patients underwent mitral valve repair for mitral regurgitation. There were 9 male and 9 female patients aged from 19 to 68 years(mean, 53). Thirteen patients were in New York Heart Association(NYHA) class III and IV. The cause of mitral regurgitation was degenerative in 12 patients, rheumatic in 5 patients and infective in 1 patient. Fifteen patients were in Carpentier's functional classification II, 2 patients in Carpentier's class III and 1 patient in Carpentier's class I. Surgical procedures included prosthetic ring annuloplasty(16 cases), rectangular resection of posterior leaflet(15 cases), chordal shortening(5 cases), triangular resection of anterior leaflet(2 cases), commissurotomy(2 cases), partial transposition of posterior leaflet(1 case). These procedures were combined in most patients. There was no operative death. These patients have been followed from 1 to 15 months, mean of 6.7 months. There was one late death resulted from low cardiac output following mitral valve replacement. The function of the repaired valve in other 17 patients has remained satisfactory during the observed interval. We consider that mitral valve repair is highly satisfactory in patients with mitral regurgitation.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.5
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• pp.67-72
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• 2008

The film cooling effectiveness on a flat plate measured by pressure sensitive paint technique. Six film cooling hole were fabricated on a flat plate with 30 degree angle with respect to the surface and three blowing ratios of 0.5, 1, and 2 were tested. Results showed that PSP technique successfully evaluated the distribution of film cooling effectiveness and showed similar results with references. The film cooling effectiveness near the film cooling holes was higher for lower blowing ratio case. As the blowing ratio was increased, the film cooling effectiveness near the film cooling hole decreased due to the lift off of the coolant. At far downstream, the film cooling effectiveness for higher blowing ratio was higher due to the coolant reattachment.

• Journal of Chest Surgery
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• v.36 no.12
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• pp.928-928
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• 2003

승모판성형술 직후에 시행한 재수술에 대한 연구보고는 많지 않다. 저자들은 승모판성형술 직후 성형술 실패로 판단되는 환자에서 즉시 시행한 재수술 결과에 대해 알아보았다. 대상 및 방법: 1995년 4월부터 2001년 7월까지 세종병원에서 승모판성형술을 받은 환자 중 체외순환 이탈 직후 시행한 경식도초음파 검사에서 승모판막폐쇄부전 혹은 협착이 의미있게 잔존하거나 다른 이유로 재수술이 즉시 필요하였던 18명을 대상으로 후향적으로 조사하였다. 남녀비는 5 : 13이었고 평균 연령은 44세였다. 승모판막 질환은 폐쇄부전 12명, 협착 3명, 그리고 혼합형이 3명이었다. 원인은 류머치스성 9명, 퇴행성 8명, 그리고 심내막염이 1명이었다. 재수술의 원인은 잔존 승모판폐쇄부전 13명, 협착 4명, 그리고 좌심실천공이 1명이었다. 14명(77.8%)에서 재성형술을, 4명에서는 인공기계판막치환술이 시행되었다. 결과: 조기사망은 없었다. 조기결과는 승모판막치환을 한 4명을 제외한 14명 중 13명(92.9%)에서 0-I도의 폐쇄부전을 보였고 협착은 14명 모두 경도 이하 상태였다. 평균 33개월을 추적조사 한 결과 1명이 술 후 4개월 후 심기능부전으로 사망하였다. 승모판폐쇄부전은 9명(64.3%)에서 0-I도를, 승모판협착은 11명(78.6%)에서 경도 이하였고 재수술은 1명에서 시행되었다. 6년 생존율과 재수술로부터의 자유도는 각각 94%와 90%였다. 4년 후 승모판폐쇄부전 및 협착 재발로부터의 자유도는 각각 56%와44%였다. 결론: 승모판막성형술 직후 재수술은 양호한 조기 및 중기 생존율을 보이며 일차성형술 실패 후에도 높은 빈도에서 재성형술이 가능하다. 하지만 재성형술 시 특히 류머치스성 판막질환에서는 판막 기능부전 발생률이 높기 때문에 성형술 후 판막부전의 재발을 줄이기 위해서는 성형술의 적절한 적용 및 적응증 선별이 중요할 것으로 생각된다.