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박춘군 한국해안해양공학회 2000 한국해안해양공학회 논문집 Vol.12 No.2
설치수힙이 점차 깊어짐에 따라 해양구조물들의 형상비가 세장해지므로 이에 대한 동적해석이 더욱 중요하다. 해양구조물중에는 프레임구조로 된 것이 많은데 이들의 자유도수가 많아 동적해석에 있어서 많은 계산시간과 컴퓨터 용량이 필요하다. 본 논문에서는 프레임 구조물의 자유도수를 현저히 감소시킬 수 있는 보치환법을 개발하는 이롼으로 동적해석을 수행할 때에 필요한 3차원 등가 유체력계수들을 산정하는 방법을 제시하였다 이 방법을 검증하기 위하여 2가지 모델 예를 사용하였으며 보치환기법에 의한 등가 보의 해석결과와 상용해석 프로그램인 ANSYS과 SACS에 의한 프레임 구조의 해석결과는 아주 만족스럽게 일치하였다. For on-shore structures, dynamic analysis becomes increasingly important as the water depth increases and the structural configuration becoines slenderer. In this study, an estimation method for equivalent three dimensional (30) hydrodynamic coefficients is introduced as a part of beam permutation technique development. The beam pemlUtation technique is being developed for obtaining an equivalent beam to a frame structure in order to reduce the degrees of freedom and thus the analysis time significantly. Two 3D structures are used in order to verify the obtained equivalent 3D hydrodynamic coefficients. Two commercial softwares, ANSYS and SACS, are used for the verification. The results of the present analysis are found to be satisfactory in comparison with those by the two softwares.
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박춘군(Chun-Jun Piao),박한일(Han-Il Park) 한국해양공학회 1999 韓國海洋工學會誌 Vol.13 No.1
For offshore structures, dynamic analysis becomes increasingly important as water depth increases and structural configuration becomes more slender. In the case of dynamic analysis of frame structures, much computer time and high cost are required due to many degrees of freedom. In this paper, a new technique of permutating a segment of frame structure to a beam is developed, which is called here Beam Permutation Technique. The technique is based on definition of stiffness matrix of the beam which is obtained by defining the actions(or forces) required to obtain unit translation or rotation for each degree of freedom with all other degree of freedom restrained to zero displacement or rotation. In the technique, an assumption is made that relative positions of nodes in the ends of the segment are not variable. The technique can significantly reduce the degrees of freedom of frame structures and thus the computing time in dynamic analysis. The natural frequencies and static displacements of the permutated beam are obtained and compared to those of ANSYS with a good agreement.
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박춘군,박한일 韓國海洋大學校 附設 海洋科學技術硏究所 1999 硏究論文集 Vol.8 No.-
For offshore structures, dynamic analysis becomes increasingly important as water depth increases and structural configuration becomes more slender. In the case of dynamic analysis of frame structures, much computer time and high cost are required due many degrees of freedom. In this paper, a new technique of permutating a segment of frame structure to a beam is developed, which is called here Beam permutation Technique. The technique is based on definition of stiffness matrix of the beam which is obtained by defining the actions(or forces) required to obtain unit translation or rotation for each degree of freedom with all other degree of freedom restrained to zero displacement or rotation. In the technique, and assumption si made that relative positions of nodes in the ends of the segment are not variable. The technique can significantly reduce the degrees of freedom of frame structures and thus the computing time in dynamic analysis. The natural frequencies and static displacements of the permutated beam are obtained and compared to those of ANSYS with a good agreement.
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지윤정(Yun-Jeong Ji),이은영(Eun Young Lee),이지연(Ji Yeon Lee),서경혜(Kyung Hye Seo),김동휘(Dong Hwi Kim),박춘군(Chun Geon Park),김형돈(Hyung Don Kim) 한국영양학회 2020 Journal of Nutrition and Health Vol.53 No.3
본 연구는 선씀바귀의 항산화 및 탄수화물 소화효소 억제 효과를 평가하여 제 2형 당뇨환자에게 중요한 항산화제 및 혈당 상승 억제제로서의 가능성을 타진하고자 하였다. 선씀바귀 추출물의 총 폴리페놀, 플라보노이드 함량과 in vitro 항산화 활성 및 소화효소 저해 활성을 조사한 결과 ISE가 ISW보다 총페놀과 플라보노이드 함량이 높았고 항산화 활성 및 소화효소 저해 활성 또한 높았다. ISE의 계통분획물 중에 에틸아세테이트 분획물과 부탄올 분획물의 소화효소 저해 활성이 가장 우수하고, 추출물의 항산화활성과 탄수화물 소화효소 억제효과가 총 페놀 및 플라보노이드함량과 높은 상관성을 가지는 것으로 볼 때, ISW에 비해 상대적으로 높은 ISE의 항산화 및 소화효소 저해 활성은 페놀 화합물, 특히 플라보노이드 화합물 때문임을 알 수 있었다. 따라서 ISE와 에틸아세테이트 그리고 부탄올 분획물은 우수한 항당뇨 기능성 소재라고 판단된다. Purpose: Ixeris strigosa (IS) is a perennial plant that commonly grows in meadows. The leaves and roots of IS have been used in medicine as a sedative. This study evaluated the antioxidant and carbohydrate-digestive-enzyme inhibitory effects of IS to determine its potential as an essential antioxidant and glycemic inhibitor for type 2 diabetics. Methods: The antioxidative and α-amylase and α-glucosidase inhibitory activities were examined using the water extracts (ISW), ethanol extracts (ISE), and solvent fractions from IS. The antioxidative activities were measured using in vitro methods by measuring the 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity. Results: Investigations of the total polyphenol, flavonoid content, in vitro antioxidant activity, and α-amylase and α-glucosidase inhibitory activities of the IS extract showed that the ISE had higher total phenolic and flavonoid contents than the ISW, as well as high antioxidant activity. The ethanolic extracts of IS (70%) had an α-amylase inhibitory activity of 78.55%. The ethyl acetate fraction (90.56%) showed higher α-glucosidase inhibitory activity than the positive control, acarbose (83.01%). Conclusion: Among the ISE fractions, the ethyl acetate and butanol fractions showed the best digestive enzyme inhibitory activity. Moreover, the antioxidant activity of the extract and the carbohydrate, α-amylase, and α-glucosidase inhibitory effects showed a stronger correlation with the total phenol and flavonoid contents compared to the ISW. As a result, the antioxidant and digestive enzyme inhibitory activities of high ISE are due to the phenolic compounds, particularly the flavonoid compounds. Therefore, ethyl acetate and butanol fractions of the 70% ethanol extract are excellent anti-diabetic functional materials.
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