섬유강화 복합재료에서 결함의 보강재에 의한 강도 평가

이문철(Moon-Chul Lee),최영근(Young-Geun Choi),이택순(Taik-Soon Lee) 한국해양공학회 1994 韓國海洋工學會誌 Vol.8 No.1

The use of advanced composite materials has grown in recent years in aerospace and other structures. Out of various kinds of repairing methods the one selected for this study is an idealized case which simulates a situation where a damaged laminate has been repaired by drilling a hole and thereafter plugging the hole with reinforcement. Two types of reinforcement are investigated ; adhesively bonded plug reinforcement or snug-fit unbonded plug in the hole. For each case of reinforcement, four different sizes of hole diameter and three types of reinforcing material (steel, aluminum, plexiglass) are employed for investigation.<br/> The experiment are mainly forced on the evaluation of ultimate strength of laminate with reinforced hole in comparison to its counterpart with the open hole.

SiOG 공정을 이용한 고 신뢰성 MEMS 자이로스코프

이문철,강석진,정규동,좌성훈,조용철,Lee Moon Chul,Kang Seok Jin,Jung Kyu Dong,Choa Sung-Hoon,Cho Yang Chul 한국마이크로전자및패키징학회 2005 마이크로전자 및 패키징학회지 Vol.12 No.3

MEMS에서 제조 공정 오차 및 외부 응력은 진동형 자이로스코프와 같은 MEMS 소자의 제조 수율에 많은 영향을 미친다. 특히 비연성 진동형 자이로스코프의 경우 감지모드와 구동모드의 주파수 차의 특성은 수율에 직접적인 영향을 미친다. SOI (Silicon-On-Insulator) 공정 및 양극접합 공정으로 패키징된 자이로스코프의 경우, 노칭현상으로 인하여 구조물이 불균일하게 가공되며, 동시에 열팽창계수 차로 인하여 접합된 기판에 큰 휨이 발생한다. 그 결과주파수 차의 분포가 커지고, 동시에 수율은 저하되었다. 이를 개선하기 위하여 SiOG (Silicon On Glass) 기술을 적용하였다. SiOG 공정에서는 접합 후에 기판의 휨을 최소화 하기 위하여 1장의 실리콘 기관과 2장의 유리 기판을 사용하였으며, 노칭을 방지하기 위하여 금속 박막을 사용하였다. 그 결과 노칭 현상이 방지되었으며, 기판의 휨도 감소하였다. 또한 주파수 차의 분포도 매우 균일하게 되었으며, 주파수 차의 편차 또한 개선이 되었다. 그 결과 높은 수율 및 보다 강건한 MEMS 자이로스코프를 개발할 수 있었다. MEMS devices such as a vibratory gyroscope often suffer from a lower yield rate due to fabrication errors and the external stress. In the decoupled vibratory gyroscope, the main factor that determines the yield rate is the frequency difference between the sensing and driving modes. The gyroscope, fabricated with SOI (Silicon-On-Insulator) wafer and packaged using the anodic bonding, has a large wafer bowing caused by thermal expansion mismatch as well as non-uniform surfaces of the structures caused by the notching effect. These effects result in large distribution in the frequency difference, and thereby a lower yield rate. To improve the yield rate we propose a packaged SiOG (Silicon On Glass) technology. It uses a silicon wafer and two glass wafers to minimize the wafer bowing and a metallic membrane to avoid the notching. In the packaged SiOG gyroscope, the notching effect is eliminated and the warpage of the wafer is greatly reduced. Consequently the frequency difference is more uniformly distributed and its variation is greatly improved. Therefore we can achieve a more robust vibratory MEMS gyroscope with a higher yield rate.

Low Pull-in Voltage MEMS Switches for Wireless Applications

Dongha Shim(심동하),Moon-chul Lee(이문철),Eun-sung Lee(이은성),Sun-hee Park(박선희),Young-il Kim(김영일),Insang So(송인상) 대한전기학회 2002 대한전기학회 학술대회 논문집 Vol.2002 No.7

Soft X-ray를 이용한 Polymer Plastic Film/Sheet In Line 두께 측정기 연구

나세흠 ( Se Hum Na ),이기홍 ( Ki Hong Lee ),조문신 ( Moon Sin Jo ),고영복 ( Young Bok Ko ),서정철 ( Jung Chul Seo ),김성수 ( Sung Su Kim ),이문용 ( Moon Yong Lee ) 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.2

패키징으로 인한 응력이 MEMS 소자에 미치는 영향 분석 및 개선

좌성훈(Sung-Hoon Choa),조용철(Yong Chul Cho),이문철(Moon Chul Lee) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.11

In MEMS (Micro-Electro-Mechanical System), packaging induced stress or stress induced structure deformation becomes increasing concerns since it directly affects the performance of the device. In the decoupled vibratory MEMS gyroscope, the main factor that determines the yield rate is the frequency difference between the sensing and driving modes. The gyroscope, packaged using the anodic bonding at the wafer level and EMC (epoxy molding compound) molding, has a deformation of MEMS structure caused by thermal expansion mismatch. Th is effect results in large distribution in the frequency difference, and thereby a lower yield rate. To improve the yield rate we propose a packaged SiOG (Silicon On Glass) process technology. It uses a silicon wafer and two glass wafers to minimize the wafer warpage. Thus the warpage of the wafer is greatly reduced and the frequency difference is more uniformly distributed. In addition, in order to increase robustness of the structure against deformation caused by EMC molding, a crab-leg type spring is replaced with a semi-folded spring. The results show that the frequency shift is greatly reduced after applying the semi-folded spring. Therefore we can achieve a more robust vibratory MEMS gyroscope with a higher yield rate.

인공 장애물에 의한 심실세동의 동역학적 변화의 광학적 지도 분석

정보영 ( Bo Young Joung ),구본권 ( Bon Kwon Koo ),서정철 ( Zheng Zhe Xu ),김일권 ( Il Kwon Kim ),황기철 ( Ki Chul Hwang ),이문형 ( Moon Hyoung Lee ),김성순 ( Sung Soon Kim ) 한국조직공학과 재생의학회 2006 조직공학과 재생의학 Vol.3 No.3

The effects of artificial obstacles on the dynamics of ventricular fibrillation have been extensively investigated with an electrical mapping system. This study was performed to assess the influence of transmural obstacles on the dynamics of wavefronts and to determine whether obstacles can convert ventricular fibrillation to ventricular tachycardia by stabilizing wavefronts in fibrillating right ventricular tissues of pigs using an optical mapping system. The right ventricles of pigs(n=15) were excised and placed in a tissue perfusion system with the epicardium facing up. A hole of increasing size from 2 mm to 8 mm in diameter was created using a skin biopsy punch. Then, the other 8mm sized hole was made just beside the first hole. The changes of wavefront dynamics and the cycle length of optical action potential waves were investigated. In 14 among 20 obstacles of ten tissues, transient attachment of electrical activities along the rim of obstacles and transient rotation of wavefronts were observed. During baseline ventricular fibrillation, fibrillation cycle length was 118.5±24.7 msec and this was increased to 135.4±30.2 msec after 8mm hole, and to 159.4±47.7 msec after 2 holes(p=0.01). There was a positive correlation between the obstacle size and cycle length(r=0.43, p=0.007). In three tissues, conversion to ventricular tachycardia from ventricular fibrillation was observed after creation of two holes. Obstacles of proper size had anti-fibrillatory effects in tissues with ventricular fibrillation and this phenomenon was partly explained by the temporary attachment of wavefronts to the obstacles.

연속파 Doppler 심초음파 검사에 의한 대동맥 및 폐동맥 혈류량의 측정

주인종(In Jong Joo),김은식(Eun Sik Kim),이문철(Moon Chul Lee),김수경(Soo Kyung Kim),유병희(Byung Hee Yu),이홍순(Hong Soon Lee),이학중(Hak Choong Lee) 대한내과학회 1987 대한내과학회지 Vol.32 No.5

N/A To measure aortic and pulmonary flow, Continuous-Wave Doppler echocardiography was performed in 30 patients who admit to N.M.C, from Mar., 1986 to Sept., 1986. We compared the measurements of aortic and pulmonary flow by CW Doppler echocardiography with those by Fick method of cardiac catheterization to evaluate the accuracy of the measurements by CW Doppler echocardiography. The results were as follows; l) Aortic and pulmonary flow measured by two methods showed a significant correlation of 0.44 (P<0.025) in aortic flow and 0.72 (P<0.005) in pulmonary flow, respectively. 2) Aortic and pulmonary flow measured by CW Doppler echocardiography showed a more significant correlation in the patients with regular heart beat and CI of above 2,2 L/min/m² than in the patients with irregular heart beat and CI of below 2.2 L/min/m² 3) Therefore, a simple & nonivasive Doppler echocardiography was considered as a effective method for measurement of aortic and pulmonary flow.

연속적 한외여과와 혈액투석중 혈장 ANP 의 변화

장규만(Kyu Man Jang),하기수(Ki Soo Ha),문현창(Hyun Chang Moon),이문철(Moon Chul Lee),유병희(Byung Hee Yu),이홍순(Hong Soon Lee),문성수(Seong Soo Moon) 대한내과학회 1988 대한내과학회지 Vol.35 No.6

N/A Plasma atrial natriuretic peptide (ANP) has been known to be a kind of peptide hormone and to have actions of natriuresis, diuresis and vasodilatation. It has been suggested that plasma ANP may be secreted from the cardiac atrium in response to extracellular fluid volume expansion to maintain blood volume homeostasis, and its level may be raised in volume overloaded conditions, such as congestive heart failure, chronic renal failure and the syndrome of inappropriate antidiuretic hormone secretion. We investigated the effect of fluid removal by sequential ultrafiltration and hemodialysis on circulating plasma ANP in 14 volume overloaded patients with chronic renal failure. The results were as follows: 1) The mean dry weight of patients was 58.3±0.4 kg and the predialytic weight gain was 3.4±0.9 kg. The amount of fluid removal by sequential ultrafilt-ration was 1176±31.7 ml (about 2% of predialytic body weight) and postdialytic weight loss was 3.1±0.3 kg. Systolic and diastolic blood pressures were not significantly changed during sequential ultrafiltration and hemodialysis, Plasma osmolality, BUN and K+ levels were not significantly changed after ultrafiltration but were significantly decreased after hemodialysis. 2) Plasma ANP levels were raised in all patients (mean±SE 205.3±30.7pg/ml, n=l4) compared with healthy contro1s (40.9±4.4 pg/ml, n=16), but showed considerable interpatient variability. 3) Plasma ANP levels fell with fluid removal during ultrafiltration (123.4±4.2 pg/ml, p<0.025) and again as fluid was removed during hemodialysis (88.7±3.1 pg/ml, p<0.05). 4) There was no significant correlation between predialytic weight gain and plasma ANP levels, and between postdialytic weight loss and plasma ANP levels. In conclusion, this study showed that the plasma ANP level was raised as body fluid volume increased in patients with chronic renal failure and fell with fluid removal after dialysis. These findings suggest that changes in body fluid volume play an important role in the regulation of ANP secretion.

앙고라 兎毛纖維의 染色性

李文澈,朴燦憲 경성대학교 1983 부산수산대학 논문집 Vol.4 No.4

The rate of dyeing and equilibrium adsorption of angora rabbit fiber with monobasic acid dyes, C. I. Acid Orange 7, C. I. Acid 88 has been investigated, as compared with wool fiber. From these values, the following results has been obtained. 1) The rate of dyeing or adsorption for angora rabbit fiber with monobasic acid in buffer solution was higher slightly than that for wool. 2) The difference in the rate of dyeing between C. I. Acid Orange7 and C. I. Acid Red 88 for angora rabbit fiber was not appreciably in initial stage. 3) The rate of dyeing for angora rabbit fiber with C. I. Acid Orange 7 was influenced strongly by pH values and salt concentration.

Community를 위한 교회내 부설유치원 계획에 관한 연구

이문철,윤충열 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(계획계)

Church-affiliated kindergarten has been established and operated to utilize open church, contributing toe community with increasing importance of educating children of in modern church. But It has been considered to be a chapelry so we need a close look on method which utilize it effectively. Therefore, This study was to analyze arrangement and plan structures of church-affiliated kindergarten. The second, examined the institution present situation and a characteristic of a user and checked a problem. The third, offered a plan that efficiently uses an facilities through relationship of church facilities and kindergarten fanilities and is maximizing community with an area resident. As a result, the arrangement of kindergarten is classified three type. The first type is complex facilities of church. The second type is complex facilities of education organization in church. The third is a independent building. This study suggests that basic data which needs to planning of church-affiliated kindergarten for Community.