• 한국자동차공학회논문집
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• 제15권1호
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• pp.78-88
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• 2007

In the present study a detailed examination of various porous media models for predicting filtration efficiency and pressure drop of diesel particulate filter (DPF), such as sphere-in-cell and constricted tube models, are attempted. In order for demonstrating their validities of correct estimation on permeability, geometry of property configurations common in commercial cordierite DPFs are correlated to the porous media flow models, and validations of predicted filtration efficiencies due to the use of different unit collectors are made with experiments. The result shows that the porosity, pore size and permeability of cordierite DPF can be successfully correlated by Kuwabara flow field with correction factor of 0.6. The unit collector efficiency predicted by sphere-in-cell model agrees very well with measurements in accumulation mode, whereas that by constricted tube model with significant prediction error.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.639-643
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• 2001

Recently, photovoltaic system has been studied widely as a renewable energy system, because it does not produce environmental pollution and it has infinity energy source from the sun. A study on photovoltaic system has a lot of problems like as reappearance and repetition of some situation in the laboratory experiment for development of MPPT algorithm and islanding detection algorithm, because output characteristics of solar cell are varied by irradiation and surface temperature of solar cell. And this system is consisted a lot of solar cell unit. Therefore, the assistant equipment which emulates the solar cell characteristics which can be controlled arbitrarily by researcher is require to the researchers for reliable experimental data. In this paper, the virtual implement of solar cell (VISC) system is proposed to solve these problems and to achieve reliable experimental result on photovoltaic system. VISC system emulates the solar cell output characteristics, and this system can substitute solar cell in laboratory experiment system. To realize the VISC, mathematical model of solar cell is studied for driving converter and the DC/DC converters are compared in viewpoint of tracking error using computer simulation. And then analysis of parallel and series characteristics was done for combination of VISC model.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6709-6714
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• 2013

Background: Breast cancer is a leading cause of death in women. The available chemotherapy drugs have been associated with many side effects. Bromelain has novel medicinal qualities including anti-inflammatory, anti-thrombotic, fibrinolytic and anti-cancer functions. Commercially available bromelain is obtained through tedious methods; therefore, recombinant bromelain may provide a cheaper and simpler choice with similar quality. Materials and Methods: This study aimed to assess the effects of commercial and recombinant bromelain on the cytokinetic behavior of MCF-7 breast cancer cells and their potential as therapeutic alternatives in cancer treatment. Cytotoxic activities of commercial and recombinant bromelain were determined using (sulforhodamine) SRB assay. Next, cell viability assays were conducted to determine effects of commercial and recombinant bromelain on MCF-7 cell cytokinetic behavior. Finally, the established growth kinetic data were used to modify a model that predicts the effects of commercial and recombinant bromelain on MCF-7 cells. Results: Commercial and recombinant bromelain exerted strong effects towards decreasing the cell viability of MCF-7 cells with $IC_{50}$ values of 5.13 ${\mu}g/mL$ and 6.25 ${\mu}g/mL$, respectively, compared to taxol with an $IC_{50}$ value of 0.063 ${\mu}g/mL$. The present results indicate that commercial and recombinant bromelain both have anti-proliferative activity, reduced the number of cell generations from 3.92 to 2.81 for commercial bromelain and to 2.86 for recombinant bromelain, while with taxol reduction was to 3.12. Microscopic observation of bromelain-treated MCF-7 cells demonstrated detachment. Inhibition activity was verified with growth rates decreased dynamically from 0.009 $h^{-1}$ to 0.0059 $h^{-1}$ for commercial bromelain and to 0.0063 $h^{-1}$ for recombinant bromelain. Conclusions: Commercial and recombinant bromelain both affect cytokinetics of MCF-7 cells by decreasing cell viability, demonstrating similar strength to taxol.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.157-158
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• 2018

In this work, we developed a customized shielded cask transport system which is equipped with a railguided travelling unit and a position adjustment unit for the cask without any crane service. The designed solid model was verified to have sufficient safety margin by using structural analysis. The developed system was introduced to a hot-cell and successfully tested and verified to have required target performance.

• 한국광물학회지
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• 제4권2호
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• pp.90-98
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• 1991

This study introduces a new structural model of 1M 2:1 trioctahedral clay minerals or, more generally, 2:1 trioctahedral phyllosilicates. The structural model requires only the chemical formulae of the clay minerals as an input and uses the regression relation (Radoslovich, 1962) to calculate the a- and b-dimensions of the phyllosilicates with the given chemical formulae. The atomic coordinates of the constituent atoms are geometrically calculated for C2/m space group under the assumption that the interatomic distances are constant. To determine the c-dimension, this study calculates the binding energies of 1M 2:1 trioctahedral phyllosilicates as a function of d(001) and find the minimum energy producing d(001). The structural model generates the cell dimensions, interaxial angles, interatomic distances, octahedral, tetrahedral and interlayer thickness, polyhedron deformation angles and atomic coordinates in the unit cell. The simulated structural parameters of phlogopite and annite are very close to the reported data by Hazen and Burnham (1973), suggesting that the structure simulation using only the chemical formule is successful, and thus, that the structural model of this study overcomes the difficulties in the previous models by other investigators.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.43-50
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• 2013

The stringent emission regulation and future shortage of fossil fuel motivate the research of alternative powertrain. In this study, a system of proton exchange membrane fuel cell has been modeled to analyze the performance of the fuel cell system for automotive application. The model is composed of the fuel cell stack, air compressor, humidifier, and intercooler, and hydrogen supply which are implemented by using the Matlab/Simulink(R). Fuel cell stack model is empirical model but the water transport model is included so that the system performance can be predicted over various humidity conditions. On the other hand, the model of air compressor is composed of motor, static air compressor, and some manifolds so that the motor dynamics and manifold dynamics can be investigated. Since the model is concentrated on the strategic operation of compressor to reduce the power consumption, other balance of components (BOP) are modeled to be static components. Since the air compressor model is empirical model which is based on curve fitting of experiments, the stack model is validated with the commercial software and the experiments. The dynamics of air compressor is investigated over unit change of system load. The results shows that the power consumption of air compressor is about 12% to 25% of stack gross power and dynamic response should be reduced to optimize the system operation.

• 대한금속재료학회지
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• 제48권5호
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• pp.469-475
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• 2010

In this study, the interfacial bond strength of a squeeze infiltrated $Al_{18}B_{4}O_{33}$/AS52 Mg composite was investigated by using a finite element method. Three types of Mg composites with volume fractions of 15, 25 and 35% were fabricated. Three-dimensional models of the composite were developed by using a unit cell model in order to determine the effective elastic modulus of the metal matrix composite and the interfacial bond strength between the whisker and magnesium matrix. After modeling, numerical results were compared with the experimental tensile test results of $Al_{18}B_{4}O_{33}$/AS52 Mg composites. The results showed that the effective modulus of the composite strongly depended on the interfacial strength between the matrix and reinforcement. Based on the numerical and experimental findings, it was found that the strong interfacial bond was achieved by the interfacial reaction product of 30 nm thick MgO, which led to an improvement in the mechanical properties of the $Al_{18}B_{4}O_{33}$/AS52 Mg composites.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.167-168
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• 2017

This paper investigates to identify an optimal for analysis of battery behavior in system-level applications such as Battery Energy Storage Systems in Smart Grid infrastructures and Electrical vehicles. At system level applications, it is mandatory to check model for meaningful equivalency and practical ability for extension from unit cell to Battery stack. The investigation of current battery models in relation to their suitability for study and analysis of system level applications of battery helpful for identification of optimal model and it also provides an intuition and direction to develop the most suitable model, if such models are not available already.

• 한국시뮬레이션학회논문지
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• 제7권2호
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• pp.45-62
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• 1998

This research is concerned with buffer management in a multi-cell FMS with an AGVS. Buffers in manufacturing systems are required to reduce blocking and starving caused by breakdowns, variability in process times, and diversity of part routing. Due to the high per unit buffer cost, which primarily consists of floor space and equipment costs, the total capacity of buffers in and FMS is very limited. Proper buffer management can provide a high system efficiency. This paper presents a buffer management model for a multi-cell FMS with an AGVS and a simulation study to compare the proposed model to a conventional buffer management model in a job shop FMS.

• 한국농공학회지
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• 제44권6호
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• pp.61-70
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• 2002

This study was performed to analyze the river fractal characteristics using GIS (Geographic Information System). In this study, topographical factors in river basin were grid-analyzed for each cell size and scale using GIS and regression formula was derived by analyzing correlation among topographical factors and cell size which were calculated here. And, a new rainfall-runoff model which is considering the calculated fractal dimension was developed to apply fur a river basin.