• 자원리싸이클링
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• 제30권1호
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• pp.3-13
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• 2021

고급강은 소비자가 원하는 적절한 조성을 갖추고 있고 비금속 개재물의 제어를 통해 높은 청정도를 지닌 강을 의미하며, 철강 제품의 품질은 2차 정련 공정에서 제어하는 것이 지배적이다. 2차 정련에서는 시간이 흐름에 따라 용강, 슬래그, 비금속 개재물, 내화물 및 합금원소 간의 복잡한 반응이 동시에 일어나기 때문에 공정에 대한 제어가 쉽지 않다. 따라서 이전 연구자들은 2차 정련의 공정 예측을 위해 Kinetic 기반의 시뮬레이션 모델을 발표하였고, 정밀한 공정 예측을 위해 현재까지 발표된 시뮬레이션 모델들의 검토 및 분석이 필요하다. 본 연구에서는 Coupled Reaction 모델 기반의 2차 정련 모델들을 분석 및 검토하였고, 시뮬레이션 결과를 검토하였다.

• 한국소음진동공학회논문집
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• 제26권3호
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• pp.315-322
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• 2016

Room acoustic properties of coupled rooms connected by an aperture has been analyzed using statistical acoustic model based on the diffused sound field assumption, which has limitation in dealing with the parameters such an room geometries and non uniform absorptivity of the boundary surfaces. In order to overcome these difficulties the acoustic diffusion model has been introduced, by which distribution of the acoustic energy density can be analyzed for various shapes and wall absorptivity. In this study acoustic properties of coupled rooms connected by an aperture(e.g. door) is analyzed using acoustic diffusion equation, which is solved numerically. The mean energy densities of two rooms obtained by the diffusion model are compared with those from the statistical model. The results show good agreement for various coupling aperture sizes and absorption coefficients. For a limiting case when the partition wall is substituted by an aperture and the two rooms eventually forms a single room, results of coupled room analysis using diffusion model show good agreement with those of a single room.

• 전기학회논문지
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• 제57권1호
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• pp.40-45
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• 2008

This paper presents an optimal design of a permanent magnet actuator(PMA) using a parallel genetic algorithm. Dynamic characteristics of permanent magnet actuator model are analyzed by coupled electromagnetic-mechanical finite element method. Dynamic characteristics of PMA such as holding force, operating time, and peak current are obtained by no load test and compared with the analyzed results by coupled finite element method. The permanent magnet actuator model is optimized using a parallel genetic algorithm. Some design parameters of vertical length of permanent magnet, horizontal length of plunger, and depth of permanent magnet actuator are predefined for an optimal design of permanent magnet actuator model. Furthermore dynamic characteristics of the optimized permanent magnet actuator model are analyzed by coupled finite element method. A displacement of plunger, flowing current of the coil, force of plunger, and velocity of plunger of the optimized permanent magnet actuator model are compared with the results of a primary permanent magnet actuator model.

• Journal of the Korean Physical Society
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• 제73권10호
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• pp.1519-1528
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• 2018

The objective of the present study is the development of a comprehensive air chemical kinetic model that includes 11 species and 54 chemical reactions for the numerical investigation of air nonequilibrium inductively coupled plasmas. The two-dimensional, compressible Navier-Stokes equations coupled with the electromagnetic-field equations were employed to describe the fundamental characteristics of an inductive plasma. Dunn-Kangs 32 chemical-reaction model of air was reconstructed and used as a comparative model. The effects of the different chemical kinetic models on the flow field were analyzed and discussed at identical/different working pressures. The results theoretically indicate that no matter the working pressure is low or high, the use of the 54 chemical kinetic model presented in this study is a better choice for the numerical simulation of a nonequilibrium air ICP.

• Ocean Systems Engineering
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• 제5권3호
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• pp.221-243
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• 2015

This paper compares simplified and finite element method (FEM) models for tower and blade in dynamic coupled analysis of floating wind turbine. A SPAR type wind turbine with catenary mooring lines is considered in numerical analysis. Floating body equation is derived using boundary element method (BEM) and convolution. Equations for mooring line, tower and blade are formulated with theories of catenary, elastic beam and aerodynamic rotating beam, respectively and FEM is applied in the formulation. By combining the equations, coupled solutions are calculated. Tower or blade may be assumed rigid or lumped body for simplicity in modeling. By comparing floating body motions, mooring line tensions and tower stresses with the simple model and original FEM model, the effect of including or neglecting elastic, rotating and aerodynamic behavior of tower and blade is discussed.

• 항공우주기술
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• 제10권2호
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• pp.94-100
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• 2011

본 논문에서는 고성능 저궤도 지구관측위성의 예비연성하중 해석결과에 대하여 평가한다. 연성하중해석을 수행하기 위하여 위성체 모델을 Craig-Bampton 모델로 축약한 후 발사체 개발업체로 제공하였다. 제공된 Craig-Bampton 모델은 인공위성의 질량행렬, 강성행렬, 가속도변환행렬 및 변위변환행렬이다. 발사체 개발업체에서는 위성체 Craig-Bampton 모델과 발사체 모델을 결합하여 연성하중해석을 수행한 후 그 결과를 제공하였다. 제공받은 연성하중해석 결과를 바탕으로 발사시 위성체가 구조적으로 이상이 없는지를 평가하였다. 평가결과 위성체는 발사하중하에서 안전함을 확인할 수 있었다.

• 전산구조공학
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• 제11권4호
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• pp.169-176
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• 1998

불연속적 거동이 탁월한 벽식 프리캐스트 구조물을 해석하기 위한 방법으로 유한요소법과 강체요소법 등이 있으나, 이들 해석법은 접합부의 거동을 정확히 반영하지 못하고 있다. 본 연구에서는 패널은 강체적 거동을 하고, 판널과 판널 사이의 접합부는 고체적 거동을 가정하는 강체-고체 복합모델(Coupled Model by Rigid and Solid bodies)에 의한 해석법을 제안하며, 간단한 모델의 예를 통해 검증하였다.

• Bulletin of the Korean Chemical Society
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• 제16권5호
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• pp.427-432
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• 1995

A model based on two coupled generalized Langevin equations is proposed to investigate the trans-stilbene photoisomerization dynamics. In this model, a system which has two independent coordinates is considered and these two system coordinates are coupled to the same harmonic bath. The direct coupling between the system coordinates is assumed negligible and these two coordinates influence each other through the frictional coupling mediated by solvent molecules. From the Hamiltonian which is equivalent to the coupled generalized Langevin equations, we obtain the transition state theory rate constants of the stilbene photoisomerization. The rates obtained from this model are compared to experimental results in n-alkane solvents.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.439-442
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• 2004

Timing delays due to VLSI circuit interconnects strongly depend on neighbor line switching patterns as well as input transition time. Considering both the input transition and input switching pattern, a new analytical timing delay model is developed by using the decoupling technique of transfer multi-coupled lines into an effective single line. The analytical timing delay model can determine the timing delay of multi-coupled lines accurately as well as rapidly. It is verified by using DSM-Technology ($0.1{\mu}m$ /low-k copper-based process) that the model has excellent agreement with the results of SPICE simulation.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.111-116
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• 2005

Two coupling methods for the Navier-Stokes equations and a two-equation turbulence model equations are compared. They are the strongly coupled method and the loosely coupled method. The strongly coupled method solves the Navier-Stokes equations and the two-equation turbulence model equations simultaneously, while the loosely coupled method solves the Navier-Stokes equation with the turbulence viscosity fixed and subsequently solves the turbulence model equations with all the flow quantities fixed. In this paper, performances of two coupling methods are compared for two and three-dimensional problems.