• Journal of Chest Surgery
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• 제21권3호
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• pp.567-573
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• 1988

Coarctation of the aorta is classically a congenital narrowing of the upper descending thorac aorta adjacent to the site of attachment of the ductus arteriosus which is sufficiently severe that there is a pressure gradient across the area. Recently we have experienced two cases of coarctation of the aorta and successfully performed resection of the sites of coarctation and end to end anastomosis of the aorta. The first case was a juxtaductal type of coarctation of the aorta with PDA and the pathology of the lesion was a diaphragm with central narrow opening. And the resection length was about 0.5cm and aortic clamping time was 20 minutes. The second case was also juxtaductal type coarctation of the aorta with mild tubular hypoplasia of aortic isthmus, left SVC and the pathology was also a diaphragm with central narrow opening. And the resection length was about 0.5cm and aortic clamping time was 29 minutes. Both postoperative course was uneventful and the patients were discharged two weeks after operation.

• 한국기계가공학회지
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• 제19권9호
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• pp.1-8
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• 2020

In this study, the optimal design of the multi-cavity mold layout and packing pressure for the automobile TCU connector cover is determined based on the injection molding analysis and the desirability function method for multi-characteristic optimization. The design characteristics to be optimized are the warpage and sink marks of the product, the scrap of the feed system, and the clamping force. The optimal design is determined by performing injection molding analysis and desirability analysis for design alternatives defined by a complete combination of five mold layouts and six-level packing pressure. The optimal design shows that the desirability values for individual characteristics are quite high and balanced, and the resulting values of individual characteristics are satisfactorily low.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.13-16
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• 2002

In this research, the design methods of the rocket joint parts were suggested. In the first section, nonlinear finite element analyses for joint parts of a composite pressure tank were performed. In the analyses, the detailed finite element modeling was performed and complex boundary conditions(contact problem, clamping force) were considered. Secondly, several guidelines for the design of joint parts were suggested. The parametric study for geometric design variables was peformed. Finally, the parametric study result was categorized for the multi-Joint part design of the axi-symmetric composite structure.

• 한국기계가공학회지
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• 제12권5호
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• pp.94-101
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• 2013

Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. The objective of this study is to implement the best plastic injection molding process for LED TV speaker frame. Moldflow analysis and simulation of plastic injection molding process were carried out in order to predict optimal modeling operation conditions and then injection molded part was produced various type of resin temperature, filling time and injection pressure variation. the result was that the best injection molding condition is set as 60bar pressure, 2sec filling time and $310^{\circ}C$ degree. The study result would be useful to variety of plastic injection molding process.

• Journal of Chest Surgery
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• 제6권1호
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• pp.47-50
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• 1973

A 16 years old Korean boy was admitted with chief complaints of exertional dyspnea, precordial pain, and headache. His brachial and femoral arterial pressure were 180/100 mmHg and 120/95 mmHg respectively. Aortogram by Seldinger technique revealed postductal adult type coarctation and marked dilation of the poststenotic aortic portion. With arfonad 40mg infusion during clamping, resection of the coarctation segment, and end-to-end anastomosis of the aorta maximal brachial arterial pressure was maintained below 180 mmHg. Postopertive course was uneventful and the patient was discharged two weeks after operation. Precordial pain and headache diasappeared. Brachial and fernoral arterial pressure were 140/80 mmHg and 110/90 mmHg at the time of discharge.

• 유공압시스템학회논문집
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• 제4권2호
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• pp.21-27
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• 2007

This paper deals with the issue of trajectory tracking control of a clamping cylinder for injection moulding machine, which is directly driven by speed controlled hydraulic pump in combination with AC servomotor. As a fundamental step prior to tracking controller design, feedback control system is developed by implementing a position control loop parallel with a system pressure control loop. A sliding mode controller combining velocity feedforward scheme is developed for enhancing the tracking performance. Consequently a significant reduction in tracking error is achieved for both position and pressure control applications.

• 약학회지
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• 제36권4호
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• pp.379-389
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• 1992

In order to investigate the effect of nifedipine, $Ca^{+2}$ channel antagoninst, on the action of some drugs participating in blood pressure, this experiment was peformed in rabbits. Nifedipine decreased the pressor actions of norepinephrine, angiotensin and carotid artery clamping, but did not affect the pressor actions of tyramine and depressor actions of acetylcholine and pilocarpine. Nifedipine inhibited the potentiated pressor action of norepinephrine and angiotensin, but did not influence the potentiated pressor action of tyramine in rabbits pretreated with chlorisondamine, ganglionic blocking agent. Nifedipine weakened the potentiated pressor action of norepinephrine, did not affect the pressor action of angiotensin and the potentiated pressor action of tyramine in rabbits pretreated with debrisoquine, sympathetic neuronal blocking agent.

• 한국항공우주학회지
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• 제36권7호
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• pp.642-650
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• 2008

고분자 전해질 연료전지 스택의 성능향상과 안전성 확보를 위하여 스택의 체결하중으로 인한 가스켓과 GDL의 구조적 거동을 살펴보았다. 가스켓 구조 해석의 경우 하중과 변위의 초탄성 거동을 표현하기 위하여 Mooney-Rivlin의 변형률에너지 함수를 사용하였으며, 재료물성을 구하기 위하여 단축 인장 및 등가 이축 인장 시험을 수행하였고 유한요소 해석과 비교하였다. GDL의 물성측정을 위하여 압축 하중의 변화에 따라 두께변화를 측정하였고 단위 셀을 제작하여 하중의 변화에 따른 채널의 압력차를 측정하였다. 실험 데이터를 바탕으로 채널 단면적의 변화를 계산, 유한요소 해석결과와 비교하였다.

• 한국기계가공학회지
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• 제13권6호
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• pp.73-81
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• 2014

In this paper, multiple gate locations and process conditions under concern are automatically optimized by considering robustness to minimize the injection pressure required to mold an automotive dashboard. Computer simulation-based experiments using orthogonal arrays(OA) and a design-range reduction algorithm are consolidated into an iterative search scheme, which is then used as a tool for the optimization process. The robustness of a design is evaluated using an OA-based simulation of process fluctuations due to noise as well as the signal-to-noise ratio. The optimal design solution for the automotive dashboard shows that the robustness of the injection pressure is significantly improved when compared to the initial design. As a result, both the die clamping force and the pressure distribution in the part cavity are also much improved in terms of their robustness.

• Composites Research
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• 제36권6호
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• pp.422-428
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• 2023

스택 체결압에 의해 접촉되는 분리판(BP)과 탄소펠트전극(CFE) 사이의 전기적 접촉저항은 상대적으로 낮은 바나듐 레독스 흐름전지(VRFB) 스택의 체결압 때문에 스택 효율에 큰 여향을 미친다. 본 연구에서는 이러한 접촉저항을 줄이고 셀 성능을 향상시키기 위해 국부 가열 접합 공정을 통해 폴리에틸렌(PE) 복합재료-CFE 하이브리드 BP 구조를 개발하였다. 탄소섬유 복합재료 BP의 PE 매트릭스를 국부적으로 녹여 CFE의 탄소 섬유와 BP의 탄소 섬유의 직접 접촉 구조를 만들어 전기 접촉 저항을 감소시겼다. PE 복합재료-CFE 하이브리드 BP의 성능을 평가하기 위해 면적비저항(ASR)과 기체투과도를 측정하였다. 또한 스택 신뢰성을 측정하기 위해 내산성 시험을 수행하였다. 최종적으로, 개발된 PE 복합재료-CFE 하이브리드 BP와 기존의 BP의 성능을 비교 분석하기 위하여 VFRB 단위셀 충/방전 시험을 수행하였다.