살모사 교상 후에 발생한 뇌간 경색

권석범,이병철,배재천,황성희,김대훈 대한신경과학회 1998 대한신경과학회지 Vol.16 No.4

상부요로폐색환자에서 신주사상 분리신기능과 크리아티닌청소치 비율의 비교

정헌영,서기석,김종성 大韓泌尿器科學會 1998 Korean Journal of Urology Vol.39 No.2

고압 커패시터의 고장 분석을 통한 신뢰도 예측

양석준,김진우,신승우,이희진,신승훈,유동수,장석원 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.6

본 논문은 고압 커패시터의 고장분석과 신뢰성 예측 결과를 다루고 있다. 부품의 수명과 고장률을 예측하기 위해서 두 가지 방법으로 고장 모드와 고장 메커니즘을 연구하였다. 에폭시 수지로 성형된 고압 커패시터가 절연내압 시험 하에서 저항이 제로로 되는 고장에 대하여, 근본원인 고장분석 체계를 효과적으로 수립함으로써 고장 메커니즘의 원인을 분석하였다. 특히 세라믹-에폭시 계면에서의 절연파괴 고장 현상이 강조되었으며, 본 연구에서 얻어진 결과의 타당성은 마그네트론에 장착된 고압 커패시터의 열사이클 시험 수행에 의한 가속시험 결과로부터 입증되었다. 시험 결과들은 결함이 있는 로트를 신속히 규명하고 B10수명을 결정하는데 유용하게 사용할 수 있다. 또한, 유전체의 절연파괴에 대해서 부하-강도 간섭모델을 이용하여 고장률을 예측하였다. This paper presents a result of failure analysis and reliability evaluation for high voltage ceramic capacitors. The failure modes and failure mechanisms were studied in two ways in order to estimate component life and failure rate. The causes of failure mechanisms for zero resistance phenomena under withstanding voltage test in high voltage ceramic capacitors molded by epoxy resin were studied y establishing an effective root cause failure analysis. Particular emphasis was placed on breakdown phenomena at the ceramic-epoxy interface. The validity of the results in this study was confirmed by the results of accelerated testing. Thermal cycling test for high voltage ceramic capacitor mounted on a magnetron were implemented. Delamination between ceramic and epoxy, which might cause electrical short in underlying circuitry, can occur during curing or thermal cycle. The results can be conveniently used to quickly identify defective lots, determine B10 life estimation each lot at the level of inspection, and detect major changes in the vendors processes. Also, thd condition for dielectric breakdown was investigated for the estimation of failure rate with load-strength interference model.

Line Drawing Image의 처리와 벡터화 시스템

배석찬,이태헌,신성윤 群山大學校 1996 論文集 Vol.23 No.-

This paper proposes an approach to the segmentation, vectorization and representation of large-size line drawing images. The scaned digital image used to preprocessing and vectorization, resulting data was transffered CAD/CAM system. Processing step was noise removal, void filling, image segmentation, line thinning and contour extraction. Raster-to-vector conversion was performed by recognition and fitting of straight line segments, circles, arcs, and conic section. Experimental results are also shown

이소부틸로니트릴의 합성에 따른 촉매의 영향

변헌수,전남석 여수대학교 1998 論文集 Vol.13 No.2

By the catalytic dehydration, these are obtained to the preparation of isobutyronitrile from isobutyl aldehyde with the various catalyst: platinum metal on activated carbon, palladium on activated carbon, zinc metal. AgNO₃, cobalt oxide, alumina-supported zinc oxide. The available catalyst was selected by the conversion ratio of the isobutyronitrile from isobutyl aldehyde over the atmosphere pressure at 150 and 300℃. By the experimental data, it was available for the preparation of this to alumina-supported zinc oxide as a catalyst. And it was available for this preparation with the selected catalyst to the temperature from 380 to 420℃.

지진격리설계에서 교량모델링 기법

시석훈,김충호 경성대학교 공학기술연구소 2000 공학기술연구지 Vol.7 No.-

In modelling seismic isolation systems, the flexibility of the bearing must be modelled correctly so that the period shift is reflected in the results and the model must reflect the reduction in response caused by the hysteretic damping. In the study, the lead rubber bearing(LRB) were each modelled as cantilever beam element at the bearing locations and reduction in response caused by the hysteretic damping was involved by composite spectrum modified the caltrans ARS spectrum curve. The comparison between the LEADeR program and the MIDAS results demonstrates that the values obtained from the modeling are sufficiently accurate to access the benefits of the seismic isolation scheme.

응급실에서 급성 췌장염 환자의 선별을 위한 actim pancreatitisR검사의 유용성

송석훈,도병수,이삼범 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Acute pancreatitis is a fairly common abdominal disorder that can be easily confronted in the emergency department(ED) and is one of the most complex and clinically challenging of all abdominal disorders. Currently, there is no gold standard for the diagnosis of acute pancreatitis. We evaluated the usefulness of the actim Pancreatitis□ rapid test, which has been recently developed in Europe, as a screening test of acute pancreatitis in our emergency department. Methods: We prospectively studied the urinary trypsinogen-2 dipstick tests(actim Pancreatitis□, Medix Biochemica, Kauniainen, Finland) of 200 patients with acute abdominal pain who were treated at our ED. All urine samples were collected from the patients within 12 hours of arrival at ED. We also measured serum amylase assay in the laboratory and compared the sensitivities and the specificities of the two test. Acute pancreatitis was diagnosed by authors according to standardized criteria. Abdominal USG or CT was performed when a patient with a normal serum amylase level had a typical clinical presentation. Results: The actim Pancreatitis□ rapid test was positive in 22 of the 25 patients with acute pancreatitis(sensitivity, 88.0 percent). The test was also positive in 6 of 175 patients without pancreatitis(specificity, 96.6 percent). The serum amylase assay had a sensitivity of 68.0 percent(with a cutoff value of 300 U per liter for the upper reference limit) and a specificity of 90.9 percent. But there were no statistical differences between the correlation coefficients of the two tests as diagnostic tool Conclusion: In patients with acute abdominal pain who are seen in the emergency department, the actim Pancreatitis□ urinary dipstick test has a high degree of probability as a screening test for acute pancreatitis. Also it can easily and rapidly be use at the bedside.

3차원 지그 설계 시스템의 도면 작성 지원 기능의 개발

이상헌,김석렬 국민대학교 생산기술연구소 2004 공학기술논문집 Vol.27 No.-

Modeling and simulation are emerging as key technologies to support manufacturing, which offer great potential for improving products, perfecting processes, reducing design-to-manufacturing cycle time, and reducing product realization costs. Especially 3-D shape modeling and simulation is a very effective tool for the design and production of automotive body assembly lines. Therefore, 3-D CAD systems have been widely adopted in the design of welding jig systems that are the main components of body assembly lines. However, the production process of a jig system still requires 2-D drawings. Therefore, it is necessary to create drawings from 3-D jig models. However, commercial 3-D CAD systems do not provide as convenient tools as 2-D CAD systems, nor specialized functionalities for the jig drawings. To solve this problem, we customized Unigraphics, a commercial CAD system, for the specific jig drafting process. Several drafting utilities have been developed in this project, which are balloon creation, car-line creation, symbol creation, parts list generation, and check sheet generation utilities. By introducing these drafting utilities, a jig system can be drafted more efficiently and reduce the time and cost of the jig design and production.

CPW급전을 이용한 UWB 안테나 설계

최석호,이성훈,김학선,박종권 한밭대학교 정보통신전문대학원 2004 정보통신전문대학원 논문집 Vol.2 No.1

본 논문은 CPW급전 구조와 CST사의 Microwave Studio 사용하여 UWB 안테나를 설계하였다. 시물레이션 결과 제안된 안테나의 대역폭은 3.O5-13GHz를 가지고 방사패턴은 무지향성의 형태를 갖는 것을 보였다. In this paper, we have designed a UWB antenna using CPW feed line and used the Microwave Studio of CST to simulate the UWB antenna. Simulated results show that antenna bandwidth is 3.05-13GHz and radiation pattern is omni-directional.

비선형 웹 이송 시스템의 장력제어

윤석찬,백승훈,정진태,한창수 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.5

This paper presents the study of the tension control in a web transfer system. In this study the sliding mode controller is applied to a time-varying nonlinear mathematical model. The model was derived to consider the effects of changing the roll rad;us in tension variation during winding and unwinding. The uncertainty in modeling may be due to unmodelled dynamics, on variations in system model. Designed sliding mode controller made the system error always staying in the suggested surface from the beginning. Through this, system is maintained to be robust against a disturbance and uncertainty. To verify the designed controller has a good performance, various inputs such as desired velocity, step input, and trapezoidal input are applied. When the sliding mode controller was used, the system(the tension control) performance was improved comparing to the PID controller. The robustness of the controller with respect to an estimation error was verified through simulations.