• Journal of the Korean Society of Visualization
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• v.21 no.3
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• pp.93-100
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• 2023

The yeast Saccharomyces cerevisiae (S. cerevisiae) is considered an ideal eukaryotic model and has long been recognized for its pivotal role in numerous industrial production processes. Depending on the cell cycle phases, microenvironment, and species, S. cerevisiae varies in shape and has different sizes of each shape such as singlets, doublets, and clusters. Obtaining high-purity populations of uniformly shaped S. cerevisiae cells is crucial in fundamental biological research and industrial operations. In this study, we propose an acoustofluidic method for separating S. cerevisiae cells based on their size using surface acoustic wave (SAW)-induced acoustic radiation force (ARF). The SAW-induced ARF increased with cell diameter, which enabled a successful size-based separation of S. cerevisiae cells using an acoustofluidics device. We anticipate that the proposed acoustofluidics approach for yeast cell separation will provide new opportunities in industrial applications.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.825-828
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• 2005

In this paper, we propose a new nonvolatile unit memory cell and proposal peripheral circuit using the polymer material. Memory that relies on bistable behavior- having tow states associated with different resistances at the same applied voltage - has attracted much interest because of its nonvolatile properties. Such memory may also have other merits, including simplicity of structure and manufacturing, and the small size of memory cells. We have plotted the load line graphs for the use of a polymer memory character, hence we have designed in the band-gap reference shape of a write/erase drive, and then designed in the 2-stage differential amplifier shape of a sense amplifier in the consideration of a low current characteristic of a polymer memory cell. The simulation result shows that is has high gain about 80dB by sensing the very small current.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.58-64
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• 2011

In this paper, research on the manufacturing technology of hexagonal structure core is investigated. Also the optimal forming process of the honeycomb core is developed and the rolling process is analyzed using finite element code, $DEFORM^{TM}$-3D. The standard honeycomb has a uniform hexagonal structure defined by the material, cell size, cell wall thickness and bulk density. Honeycomb core products can be made from any thin, flat material. The most common cell configuration is the hexagon but there are many other shapes for special applications. Because of the precision shape and the thin thickness, the honeycomb core is not easy to manufacture in the metal forming process. Through this study it was confirmed that after the rolling process, the section of honeycomb close to the standard shape can be obtained. This result is reflected to the manufacturing process design for the honeycomb core.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.3
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• pp.147-156
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• 2008

A new approach based on cone prism intersection method combined with sorting algorithm is proposed for the fast and robust signed distance field computation. In the method, the space bounding the geometric model composed of triangular net is divided into multiple smaller cells. For the efficient calculation of distance fields, valid points among the triangular net which will generate minimum distances with current cell are selected by checking the intersection between current cell and cone prism generated at each point. The method is simple to implement and able to achieve an order of magnitude improvement in the computation time as compared to earlier approaches. Further the method is robust in handling the traditional sign problems. The validity of the suggested method was demonstrated by providing numerous examples including Boolean operation, shape deformation and morphing of complex geometric models.

• Korean Journal of Animal Reproduction
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• v.4 no.1
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• pp.13-19
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• 1980

This experiment was carried out to observe early morphological changes of luteal cells in Korean native cattle treated with prostaglandin F2$\alpha$. Twenty five gram of prostaglandin F2$\alpha$ was administrated per cow at 10 days after ovulation and luteal cells were removed 30, 60, 120 and 180 minites after administration. Morphological changes of each luteal cell was observed by electron microscope. the results obtained were summarized as followings: 1. Many electron-dense granules were observed in luteal cells obtained from control cow but those granules were decreased rapidly after 30 minutes of administration and no granules were obresved after 180 minutes of administration. 2. In control, the shape of mitochondria were begining to collapse from the time of 60 minutes after administration. After 180 minutes of administration, mitochondria were swelled extreamly. 3. Lipid droplets in luteal cell were increased in its size and number with the duration of time after administration. 4. Shape of smooth endoplasmic recticulum was vesicular and its dimension and number were increased according to time course after administration.

• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.373-381
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• 1994

An actinomycete strain, HSL-613 was isolated -from soil and identified by International Streptomyces Project (ISP) and chemotaxonomic methods. The spore chain of the strain HSL-613 appears in a spiral shape, and its spores are spherical shape with smooth surface. The cell wall contains LL-diaminopimelic acid (DAP). Menaquinone MK-9 (H$_{6}$, H$_{8}$) and iso- and anteiso-branched fatty acids were detected from whole cell extract. Sugars identified from whole cell extract include galactose, glucose, mannose and ribose, which are distinct from general sugar patterns of Streptomyces. Average G+C content in the chromosome is 59%. 5S rRNA of HSL-613 consists of 120 nucleotides as determined by comparing with that of a type strain Streptomyces griseus subsp. KCTC 9080. Through morphological, physiological, and chemical characterization, HSL-613 was identified and named as Streptomyces sp. HSL-613.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.220-223
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• 2009

Metallic bipolar plate for molten carbonate fuel cell(MCFC) is composed of the shielded slot plate and the center plate. Among these, the center plate plays an important role in gas sealing. Therefore, manufacturing of the center plate is considered one of the key issues in MCFC. The center plate is manufactured by bending process. In bending process, springback and recoiling are two main problems. By using the modified punch shape with 'step', springback and recoil are reduced. The aim of this article is to find the effect of modified punch shape. So, the bending stress along thickness direction and material direction were investigated using FEM.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.4
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• pp.245-255
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• 2021

Various studies about metallic bipolar plates have been conducted to improve fuel cell performance through flow field design optimization. These research works have been mainly focused on fuel cells for vehicle, but not fuel cells for building. In order to reduce the price and volume of fuel cell stacks for building, it is necessary to apply a metallic flow field, In this study, for a metallic flow field applied to a fuel cell for building, the effect of a change in the flow field shape on the performance of a polymer electrolyte membrane fuel cell was confirmed using a model and experiments with a down-sizing single cell. As a result, the flow field using a metal foam outperforms the channel type flow field because it has higher internal differential pressure and higher reactants velocity in gas diffusion layer, resulting in higher water removal and higher oxygen concentration in the catalyst layer than the channel type flow field. This study is expected to contribute to providing basic data for selecting the optimal flow field for the full stack of polymer electrolyte membrane fuel cells for buildings.

• Journal of Plant Biology
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• v.39 no.2
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• pp.137-144
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• 1996

Scanning electron microscope revealed several taxonomically useful characters in the perigynium and achene epidermis of sect. Siderosticatae (Carex siderosticta, C. ciliatomarginata and C. okamotoi). Mocroscopic characters such as perigynium shape, hair presence or absence, beak shape, nodule situation in perigynium, achene shape, cell wall and silica cone in achene were useful in Carex at the species levels. A key was presented on the basis of features obtained from the examinations.

• Fibers and Polymers
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• v.5 no.3
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• pp.182-186
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• 2004

The effect of braid construction parameters on yarn cross-sectional shape is presented in this paper. The location of the yam within the braid unit cell is quantified by a compaction factor. A range of braided fabrics were produced and optically measured for actual yarn cross-sectional shape. A comparison of the theoretical and experimental values shows good correlation. Design curves can be produced with the developed model to allow selection of appropriate braid process parameter to create yarns with desired cross-sectional geometries.