• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.375-382
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• 2003

Porous media consist of physically and chemically different materials and have an extremely complicated behavior due to the different material properties of each of its constituents. In addition, the internal structure of porous media has generally a complex geometry that makes the description of its mechanical behavior quite complex. Thus, in order to describe and clarify the deformation behavior of porous media, constitutive models for deformation of porous media coupling several effects such as flow of fluids of thermodynamical change need to be developed in frame of Arbitrary Lagrangian Eulerian (ALE) description. The aim of ALE formulations is to maximize the advantages of Lagrangian and Eulerian methods, and to minimize the disadvantages. Therefore, this method is appropriate for the analysis of porous media that are considered for the behavior of solids and fluids. First of all, governing equations for saturated porous media based on ALE description are derived. Then, weak forms of these equations are obtained in order to implement numerical method using finite element method. Finally, Petrov-Galerkin method Is applied to develop finite element formulation.

• 대한전기학회논문지:전력기술부문A
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• 제50권1호
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• pp.6-12
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• 2001

This paper deals with the development of dynamic equivalents of the Korea Electric Corporation (KEPCO) systems. The weak coupling method is chosen for the most suitable coherency identification to represent the characteristics of the KEPCO system by the dynamic characteristic comparison of several coherency identification methods. Also, this paper shows the detail aggregation of generator groups makes a better representation of the dynamic and static characteristics of the original system than the classical aggregation. The simulation results of the developed KEPCO equivalent system are presented in comparison with the original system to illustrate the validity of the equivalent system are presented in comparison with the original system to illustrate the validity of the equivalent system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1996-1998
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• 2001

This paper presents the closed-loop composite control for weakly coupled bilinear systems with a quadratic performance criterion. The Riccati equation for weakly coupled bilinear system is decomposed into three reduced Riccati equations by the weak coupling theory, and we obtain optimal solutions of each reduced Riccati equation using successive Galerkin approximation(SGA). We design the composite control law that consists of optimal solutions of each reduced Riccati equation. The proposed algorithm reduces the disadvantages of SGA method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.147-150
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• 1999

In the case of immobilizing of glucose oxidase in organic polymer using electrosynthesis, the glucose oxidase obstructs charge transfer and mass transport during the film growth. This may lead to short chained polymer and/or make charge-coupling weak between the glucose oxidase and the backbone of the polymer. That is mainly due to insulating property and net chain of the glucose oxidase. Since being the case, it is useless to increase in amount of glucose oxidase more than reasonable in the synthetic solution. We establish qualitatively that amount of immobilization can be improved by adding a little ethanol in the synthetic solution. As ethanol was added by 0.1 rnol dm" in the synthetic solution, Michaelis-Menten constants of the resulting enzyme electrode decreased from 30.7 mmol $dm^{-3}$ to about 2 mmol $dm^{-3}$. That suggests increase in affinity of the enzyme electrode for glucose and in amount of the immobilized enzyme.zyme.

• 한국소음진동공학회논문집
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• 제11권6호
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• pp.175-180
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• 2001

Dynamic response localization of simple mistuned periodic structures is presented in this paper Mistuning in periodic structures can cause forced responses that are much larger than those of perfectly tuned structures. So mistuning results in the critical impact on high cycle fatigue of structures. Thus, it is of great importance to predict the mistuned forced response in an efficient way. In this paper, forced responses of coupled pendulum systems are investigated to identify the localization effect of periodic structures. The effects of mistuning and damping on the maximum forced response are examined. It is found that certain conditions of mistuning and coupling can cause strong localization and the localization becomes significant under weak damping. It is also found that the maximum forced response increases as the number of Periodic structures increases.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.79-83
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• 2005

SEA is a useful tool to predict noise and vibration response in high frequency region but has a weak point not to be able to express modal behavior in low frequency region. For a structure with middle subsystem having relatively higher modal density than excited subsystem and receiving subsystem, we studied the possibility that the modal behavior of receiving subsystem can express by considering finite mobility of excited subsystem. For a simply three-coupled beams which is chosen for feasibility study, the response of receiving beam was investigated with varying the length & area moment of inertia of middle beam. In case that the middle beam has relatively higher modal density than exciting beam, the application to finite mobility of excited beam led to express modal behavior of receiving beam relatively well.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.157-162
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• 1996

A novel nodal method is developed for the two-dimensional multi-group diffusion equations based on the Spectral-Galerkin approach. In this study, the nodal diffusion equations with Robin boundary condition are reformulated in a weak (variational) form, which is then approximated spatially by choosing appropriate basis functions. For the nodal coupling relations between the neighbouring nodes, the continuity conditions of partial currents are utilized. The resulting discrete systems with sparse structured matrices are solved by the Preconditioned Conjugate Gradient Method (PCG) and sweeping technique. The method is validated on two test problems.

• 대한수학회지
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• 제58권4호
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• pp.873-894
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• 2021

In this paper, we consider the Gudnason model of 𝒩 = 2 supersymmetric field theory, where the gauge field dynamics is governed by two Chern-Simons terms. Recently, it was shown by Han et al. that for a prescribed configuration of vortex points, there exist at least two distinct solutions for the Gudnason model in a flat two-torus, where a sufficient condition was obtained for the existence. Furthermore, one of these solutions has the asymptotic behavior of topological type. In this paper, we prove that such doubly periodic topological solutions are uniquely determined by the location of their vortex points in a weak-coupling regime.

• Clinical and Experimental Reproductive Medicine
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• 제17권1호
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• pp.71-80
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• 1990

항정자항체를 검사할 수 있는 면역분석법개발을 위하여 immunoaffinity chromatography로 분리 정제한 정자표현항원을 microtiter plate에 고정화 시킨것과 효소와 화학발광체로 표지된 2차항체를 사용하여 ELISA법과 CIA법을 개발하고 이 방법의 이용 가능성을 검토하기 위하여 기존 방법인 Kibrick test법으로 임상소견이 다른 남성혈청을 분석 비교하여 다음과 같은 결과를 얻었다. 1. 인간정자 표면항원을 분리하기 위한 immunoaffinity column을 제작키 위하여 인간정자를 토끼에 주사하여 정자에 대한 항혈청을 생산하였으며 이를 Protein A-Sepharose column으로 분리 정제하여 CNBr activated Sepharose-4B에 coupling시켜 immunoaffinity column을 제작하였다. 이 column에 균질화된 정자를 반응시키고 SDS를 넣은 Tris-HCI buffer로 용출시켰을때 60KD정도의 분자량을 갖는 분획을 얻었다. 2. 분리 정제된 human IgG를 microtier plate에 농도를 달리하여 고정화 시키고 ELISA용 Goat anti-human IgG-HRP conjugate와 CIA용 Rabbit anti-human IgG-ABEI-H conjugate와 반응시켜 그 활성도를 측정하였던 바 농도에 따라 반응의 정도가 감소하였다. 3. ELISA법으로 양성혈청의 희석곡선을 작성하였을때 경사가 완만한 것과 급한 것의 두 종류의 경향을 띈 곡선으로 대별되었으며 완만한 경사를 나타내는 것에서 1:160 희석치에서 O.D가가 0.1이하를 음성, 0.1이상 0.2이하를 약양성(weak positive) 그리고 0.2이상을 양성으로 판별하였다. 4. ELISA, CIA 그리고 Kibrick test로 동일시료를 분석 비교하였던바 ELISA와 CIA는 거의 동일한 상관관계를 보였으나 Kibrick test와는 50% 수준만 일치함을 보였다.

• Structural Engineering and Mechanics
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• 제75권4호
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• pp.487-496
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• 2020

Most of the previous works on numerical analysis of galloping of transmission lines are generally based on the quasisteady theory. However, some wind tunnel tests of the rectangular section or hangers of suspension bridges have shown that the galloping phenomenon has a strong unsteady characteristic and the test results are quite different from the quasi-steady calculation results. Therefore, it is necessary to check the applicability of the quasi-static theory in galloping analysis of the ice-covered transmission line. Although some limited unsteady simulation researches have been conducted on the variation of parameters such as aerodynamic damping, aerodynamic coefficients with wind speed or wind attack angle, there is a need to investigate the numerical simulation of unsteady galloping of two-dimensional iced transmission line with comparison to wind tunnel test results. In this paper, it is proposed to conduct a two dimensional (2-D) unsteady numerical analysis of ice-covered transmission line galloping. First, wind tunnel tests of a typical crescent-shapes iced conductor are conducted firstly to check the subsequent quasisteady and unsteady numerical analysis results. Then, a numerical simulation model consistent with the aeroelastic model in the wind tunnel test is established. The weak coupling methodology is used to consider the fluid-structure interaction in investigating a two-dimension numerical simulation of unsteady galloping of the iced conductor. First, the flow field is simulated to obtain the pressure and velocity distribution of the flow field. The fluid action on the iced conduct at the coupling interface is treated as an external load to the conductor. Then, the movement of the conduct is analyzed separately. The software ANSYS FLUENT is employed and redeveloped to numerically analyze the model responses based on fluid-structure interaction theory. The numerical simulation results of unsteady galloping of the iced conduct are compared with the measured responses of wind tunnel tests and the numerical results by the conventional quasi-steady theory, respectively.