• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.68-71
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• 2004

Recently, a great deal of research and development of a fuel cell have been carried out to solve problems on the drain of fossil fuel, air pollution and global warning. In order to improve the efficiency of a fuel cell, it is necessary to clarify the flow in separator. In this study, distributions of velocity flow rate and pressure, and streamlines are examined in detail from numerical analysis with CFD code. In the experiment the distribution of flow rate is measured and flow in the each grooves of the separator is visualized by dye method changing Reynolds number. Furthermore, effects of size of the inlet and outlet manifolds and shape of ribs near the inlet outlet on the distributions of flow and pressure are examined.

• Journal of Information Display
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• v.3 no.2
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• pp.13-18
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• 2002

Numerical simulation is one of the most useful tools to study gas discharge phenomena that occur in alternating current plasma display panel (AC-PDP) cell. Most PDP cell simulations have been performed for two-dimensional cell, is cross-section along the address electrode. We developed a three-dimensional PDP simulator and applied it to a T-shaped electrode cell in order to show the effects of sustain electrode shape that cannot be included in two-dimensional simulation. The dependence of power consumption on electrode shape and area in the simulation showed the same trend as experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.779-780
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• 2012

• Applied Microscopy
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• v.12 no.2
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• pp.55-68
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• 1982

The study on the nerve cells in the pars intercerebralis(IP) of 5-day-old cabbage butterfly Pieris rapae L. was performed to observe their ultrastructures and classify them on the basis. of the differences in size, shape and relative distribution cf cell organelles. The brain-subesophageal ganglion complex was fixed in 1% paraformaldehyde-1% gluaraldehyde mixture and embedded in araldite mixture. The transverse thin sections of IP were stained with uranyl acetate and lead citrate and examined by Hitachi 500 and ]EM 100B electron microscope. Five distinct types. of nerve cells are recognized and are arbitrarily designated as Type I, Type II Type III, Type IV and Type V. Type I neurone: These neurones are neurosecretory cells. Several neurosecretory cells are. recognized in the pars intercerebralis. They are roughly round or peach-shaped cells measuring $13{\sim}25{\mu}m$ in diameter. The rounded nucleus shows about $5{\sim}10{\mu}m$ in diameter. The chromatin is predominantly diffused with only occasional dense patches. The perikaryon contains numerous. mitochondria, free polyribosomes and neurosecretory granules. The neurosecretory granules are relatively uniform in electron density, and each one is about $100{\sim}400{\mu}m$ in diameter and surrounded by a single membrane. The granules are also observed mostly as in groups. In one group of neurones the cisternae of endoplasmic reticulum are distended or in other group of neurones are not distended. Golgi saccules are slightly dilated at their lateral extremities and contains. frequenty dense rounded materials. Type II neurone: Thes have the largest soma in the pars intercerebralis about $30{\sim}35{\mu}m$ in diameter. They also show roughly polygonal in shape. The nucleus is elongated or sickle-shaped. The chromatin is mainly in the euchromatin form. The perikarya in these cells are well populated with populated with free ribosomes and contain numerous mitochondria and Golgi bodies. The cisternae of granular endoplasmic reticulum are also well distributed. Type III neurone: They are oval or spindle-shaped and also medium-sized. neurones approximately $15{\sim}17{\mu}m$ in length. The nucleus is oval or slightly elongated in shape and $8{\sim}9{\mu}m$ in length. The chromatin occurs in diffused form. The cytoplasm contains many filamentous or oval mitochondria. The perikaryon has also numerous free polyribosomes and cisternae of granular endoplasmic reticulum. Type VI neurone: They are roughly polygonal in shape probably due to the close approximation of the adjacent cells. The soma is about $7{\sim}8{\mu}m$ in diameter. The nucleus is round or oval in shape and $5.0{\sim}5.8{\mu}m$ in diameter. The necleus also occupies a large proprion of the cell body. The perikaryon is well populated with free ribosomes and contains several mitochondria and cistenae of granular endoplasmic reticulum. Type V neurone: These neurones are similar to Type VI neurones in various respects such as cell size and cell inclusion, but they differ from Type IV neurones in shape. The soma is oval or slightly elongated. The cell body contains several filamentous and oval mitochondria.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.9
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• pp.2782-2791
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• 1996

The effective longitudinal shear modulus(LSM) of continuous composites is studied theoretically and numerically using 3-phase unit cell model. Circular, hexagonal and rectangular shapes of reinforced fiber are considered to predict the shear modulus as a function of elastic modulus of each phase and volume fraction of interphase and reinforced fiber. It is found that rectangular fiber shape in low fiber volume fraction($v_f$<30%) and circular fiber shape in high volume fraction($v_f$>40%) shows the higher longitudinal shear modulus. Also the obtained values of LSM for rectangular array and by numerical analysis are higher than those of hexagonal array and by theoretical analysis respectively. The reinforcing effects of interphase are more significant in cases of higher fiber volume fraction and circular fiber shape. Not only the spatial distribution and shape of reinforcing fiber but also the volume of interphase have a pronounced effects on the overall LSM. It is also found that the tangent moduous of 2-and 3-phase polymer matrix composites is insensitive to the shape and distribution of reinforcing fibers.

• Transactions of the Society of Information Storage Systems
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• v.8 no.2
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• pp.39-43
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• 2012

In spite of many advantages, the practical application of the thin film solar cell is restricted due to its low efficiency compared with the bulk type solar cells. This study intends to adopt the surface plasmon effect using nano particles to solve the low efficiency problem in thin film solar cells. By inserting Ag nano-particles in the absorbing layer of a thin film solar cell, the poynting vector value of the absorbing layer is increased due to the strong energy field. Increasing the value may give thin film solar cells chance to absorb more energy from the incident beam so that the efficiency of the thin film solar cell can be improved. In this work, we have designed the optimal shape of Ag nano-particle in the absorbing laser of a basic type thin film solar cell using the finite element analysis commercial package COMSOL. Design parameters are set to the particle diameter and the distance between each Ag nano-particle and by changing those parameters using the full factorial design variable set-up, we can determine optimal design of Ag nano-particles for maximizing the poynting vector value in the absorbing layer.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.1
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• pp.1-5
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• 2017

This study investigated the mechanical tearing of a cell membrane using a nanostructured alumina filter for easy and quick mechanical cell disruption. Nanostructured alumina filters were prepared by a multi-step aluminum anodizing process and nanopore etching process. Six different types of nanostructures were formed on the surface of the nanoporous alumina filters to compare the mechanical cell disruption characteristics according to the shape of the nanostructure. The prepared alumina filter was assembled in a commercial filter holder, and then, NIH3T3 fibroblast cells in a buffer solution were passed through the nanostructured alumina filter at a constant pressure. By measuring the concentration of proteins and DNA, the characteristics of mechanical cell disruption of the nanostructured alumina filter were investigated.

• Journal of International Society for Simulation Surgery
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• v.4 no.1
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• pp.1-8
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• 2017

In the field of tissue engineering, researches have been actively conducted to regulate stem cell fate by understanding the interaction between cell and materials. This approach is expected as a promising therapeutic method in the future medicine by utilizing differentiation of stem cells into desired cells or tissues using biomaterial. For this regenerative medicine, there exist lots of attempts to construct optimized structures of various shapes and sizes that can regulate the stem cell fate. In this review, we will empathize the topographic effect as stem cell niche on the mesenchymal stem cell (MSC) response (cell attachment, proliferation, and differentiation) according to the shape and size of the structure of the substrates, and comprehensively analyze the importance and the effect of shape and size of the surface topography.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.183-187
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• 2011

The polymer-stabilized blue phase liquid crystal (BPLC) cell has advantages such as sub-millisecond response time, wide viewing angle and no rubbing process for the alignment of liquid crystals. However, high operating voltage and low kerr constant of the polymer-stabilized blue phase liquid crystal deteriorate the electro-optical characteristic of the polymer-stabilized BPLC cell. In this paper, we proposed novel zig-zag electrode in cell layout and confirmed that proposed electrode shape could reduce an over 25 percent of operating voltage for BPLC cell without degradation of tranmittance by using Kerr constant simulation.

• Journal of the Korea Computer Graphics Society
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• v.23 no.4
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• pp.31-40
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• 2017

As 3D cell culture has recently become possible, it has been able to observe a 3D shape of cell and volume. Generally, 3D information of a cell should be observed with a special microscope such as a confocal microscope or an electron microscope. However, a confocal microscope is more expensive than a conventional microscope and takes longer time to capture images. Therefore, there is a need for a method that can reconstruct the 3D shape of cells using a common microscope. In this paper, we propose a method of reconstructing 3D cells using the focus estimator value from multi-focal fluorescence images of cells. Initially, 3D cultured cells are captured with an optical microscope by changing the focus. Then the approximate position of the cells is assigned as ROI (Region Of Interest) using the circular Hough transform in the images. The MSBF (Modified Sliding Band Filter) is applied to the obtained ROI to extract the outlines of the cell clusters, and the focus estimator values are computed based on the extracted outlines. Using the computed focus estimator values and the numerical aperture (NA) of the microscope, we extract the outline of the cell cluster considering the depth and reconstruct the cells into 3D based on the extracted outline. The reconstruction results are examined by comparing with the combined in-focus portions of the cell images.