• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.73-76
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• 2008

Bipolar Plates for PEMFC have been a key component of fuel cells with MEA, thus in this research they have been fabricated by a compression molding technique after mixing graphite powder with phenol resin. The results have shown the prominent properties compared with those by foreign advanced company with respect to the electrical conductivity and flexural strength. In addition, it has been carried out that the Voltage-Current characteristics comparison according to the unit cell experiments of bipolar plates. As a result, we have obtained good performances and we are going to research the molding feasibility of bipolar plate's flow channel.

• Journal of Korea Foundry Society
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• v.27 no.1
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• pp.36-41
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• 2007

Compressive properties of the open cell 6063 aluminum alloy foams made by the plaster molding process were investigated before and after heat treatment. Loading process was controlled at a displacement rate of 2 mm/min. Compressive strength of 10 PPI foam was the largest of the same density foams. Increase in strength after heat treatment for the bulk material was remark able, however was not for the 6063 aluminum foam. C values were in the range of $0.39{\sim}0.53$ for as cast foams and $0.13{\sim}0.16$ for T6 heat treated foams in the equation of ${sigma}^*_{pl}/{\sigma}_{ys}=C({\rho}/{\rho}_{s})^{1.5}$ and increased with cell size.

• Design & Manufacturing
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• v.2 no.6
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• pp.28-32
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• 2008

Polymer solar cells are a type of organic solar cell (also called plastic solar cell), or organic photovoltaic cell that produce electricity from sunlight using polymers. It is a relatively novel technology, they are being researched by universities, national laboratories and several companies around the world. In this paper, stamping mold of barrier ribs for polymer solar cells was manufactured by lithography and electroforming which can control the height of pattern and 80nl of barrier ribs was manufactured by using hot embossing.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.71-74
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• 2003

The cell modeling homogenization method to derive the constitutive equation considering the microstructures of the fiber reinforced composites has been previously developed for composites with simple microstructures such as 2D plane composites and 3D rectangular shaped composites. Here, the method has been further extended for 3D circular braided composites, utilizing B-spline curves to properly describe the more complex geometry of 3D braided composites. For verification purposes, the method has been applied for orthotropic elastic properties of the 3D circular braided glass fiber reinforced composite, in particular for the tensile property. Prepregs of the specimen have been fabricated using the 3D braiding machine through RTM (resin transfer molding) with epoxy as a matrix. Experimentally measured uniaxial tensile properties agreed well with predicted values obtained fer two volume fractions.

• The Korean Journal of Cytopathology
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• v.18 no.1
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• pp.81-86
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• 2007

Desmoplastic small round cell tumor (DSRCT) is a rare malignant mesenchymal neoplasm. It mainly involves the abdominal or pelvic peritoneum of male adolescents. We report here the imprint cytologic features of a case of DSRCT occurring in the intraabdominal cavity of a 21-year-old man. A microscopic examination showed moderate cellularity. The tumor cells were singly arranged and arranged in clusters. The cells had round to oval nuclei with finely granular chromatin, inconspicuous nucleoli and scanty cytoplasm. Some tumor cells showed nuclear molding, and some cells had an epitheloid appearance with a large amount of lightly eosinophilic cytoplasm. A rosette-like pattern was present. Spindle-shaped, fibroblastic stromal cells were occasionally found. The tumor cells were immunoreactive for the markers cytokeratin (AE1/AE3), epithelial membrane antigen (EMA), desmin, vimentin and neuron specific enolase (NSE).

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1160-1164
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• 2004

Generally in the case of parts used for precision products, tolerance of parts is very small. So inaccuate size of molding parts generates serious problems. Therefore, it's necessary to secure data about shrinkage on each condition or study about manufacturing process which reduces shrinkage. To apply MCPs to manufature of plastic product, this paper verifies how the amount of gas and Talc can affect to cell-morphology, and examines the relation between shrinkage and cell-morphology by using ASTM specimen formed by MCPs process.

• Molecules and Cells
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• v.45 no.2
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• pp.76-83
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• 2022

Neurons-on-a-Chip technology has been developed to provide diverse in vitro neuro-tools to study neuritogenesis, synaptogensis, axon guidance, and network dynamics. The two core enabling technologies are soft-lithography and microelectrode array technology. Soft lithography technology made it possible to fabricate microstamps and microfluidic channel devices with a simple replica molding method in a biological laboratory and innovatively reduced the turn-around time from assay design to chip fabrication, facilitating various experimental designs. To control nerve cell behaviors at the single cell level via chemical cues, surface biofunctionalization methods and micropatterning techniques were developed. Microelectrode chip technology, which provides a functional readout by measuring the electrophysiological signals from individual neurons, has become a popular platform to investigate neural information processing in networks. Due to these key advances, it is possible to study the relationship between the network structure and functions, and they have opened a new era of neurobiology and will become standard tools in the near future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.57-64
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• 2017

Today, due to the environmental regulations regarding air pollution in the EU, the use of EPS (Styrofoam) as the cushioning material in the packaging industry is decreasing. In effect, air cushioning based cushioning materials are rapidly expanding into the market and replacing EPS, due to their excellent buffering ability and environmental friendliness. This is a new selective filling type air filling material manufacturing technology that affords improvements in the amount of raw materials required, its processing and its aesthetic appearance compared to the conventional air filling cushioning materials. In this study, a multi-stage air cell filling valve molding technology is developed based on selective filling technology, which allows packages to be selectively filled in various forms by applying valve forming structure technology. This multi-stage air cell filling valve molding technology is a technique in which a plurality of injection ports are formed by laminating three layers of films, viz. a first injection film, a valve film, and a second injection film having valve ends. In the conventional technology, a separate external air injection path for injecting air into a plurality of connected air bags is needed. However, in the proposed system, an external air injection path is formed inside the air bag, Due to the lack of need for an injection furnace, the raw material and process are reduced and air is injected and then discharged, while the air bag is reduced in length to 63 ~ 66% of its normal value. The outer surface of the outer air injection path is integrated inside by maintaining the original length of the cross section, while the unnecessary folded air is injected into the interior of the air bag, This smart air filling type cushioning material manufacturing technology constitutes a big improvement over the existing technologies.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.107-110
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• 2003

본 연구에서는 3차원 브레이딩 기계를 이용하여 제작된 6 layer의 3차원 원형 형태로 브레이드된 유리 섬유 강화 복합재료의 프리프레그를 이용하여 에폭시 수지를 모체로 하는 RTM(Resin Transfer Molding) 공정을 통해 직교 이방성 복합재료를 제작하였다. 또한 탄성한계 내에서의 구성방정식을 얻기 위해 unit cell 모델링을 통해 복합재료의 기하를 모사하고 method of cells 이론과 homogenization technique를 이용하여 복합재료의 구성방정식을 나타내는 수치해석 코드를 개발하였다. (중략)

• Journal of Korea Foundry Society
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• v.21 no.4
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• pp.253-259
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• 2001

There are many methods to produce metal foams, which can be classified into three groups according to the state of the starting metal i.e. liquid or powder or solid. Three types of defects such as cell closing, cell deformation or breakdown and cell misrun are thought to be occurred when we make the open cell aluminum foams by precision casting. Filling ability of the mold slurry between preform is related with cell closing, mold collapsibility is related with cell deformation or breakdown, mold temperature and pouring pressure are related with cell misrun. These factors can be evaluated by measuring slurry fluidity, burnout strength and permeability of the mold. Properties of the plaster mold were evaluated to find optimum mold conditions for high quality open cell aluminum foam in this study. Permeability was almost zero independent of burnout conditions, however, crack initiation was found on the surface of all specimens one or two minutes after taking out from the furnace. Crack has grown and disappeared with time. This crack may facilitate the mold filling when molten metal is poured, because of the improved mold permeability. It was considered that crack initiation and disappearance was closely related with temperature difference between the surface and inner part. Knocking-out the mold is a difficult problem due to the small cell size, because continuous mesh structure of the metal foam is not strong. It is not easy to remove molding material after pouring. We can expect that water quenching can facilitate the knocking-out the mold after solidification without damaging cell structures. Collapsed particles after water quenching became bigger with the increase in time.