• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.217-222
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• 2018

In this paper, a new micro polymer chip platform and protocol were developed for rare cell sample preparation. The proposed platform and protocol overcome the current limitation of the dilution method which is based on statistics and the FACS method which expensive and requires fluorescence staining. It allows collecting exact number of target cells simply and selectively because the cells are visually confirmed during the collecting process. The collected cells can be transported or spiked into a desired locations, such as a microchamber, without cell loss. This research may applicable not only to a rare cell sample preparation for Lab on a Chip cancer diagnosis, but also to a single/double/multiple cell sample preparation for a cell analysis field. To verify this platform and protocol, five human breast cancer cells (MCF-7) were collected and transported into a hemocytometer chamber.

• Journal of Microbiology and Biotechnology
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• v.32 no.4
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• pp.531-540
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• 2022

Due to the high incidence of malignant melanoma, the establishment of in vitro models that recapitulate the tumor microenvironment is of great biological and clinical importance for tumor treatment and drug research. In this study, 3D printing technology was used to prepare GelMA/PEGDA composite scaffolds that mimic the microenvironment of human malignant melanoma cell (A375) growth and construct in vitro melanoma micro-models. The GelMA/PEGDA hybrid scaffold was tested by the mechanical property, cell live/dead assay, cell proliferation assay, cytoskeleton staining and drug loading assay. The growth of tumor cells in two- and three-dimensional culture systems and the anti-cancer effect of luteolin were evaluated using the live/dead staining method and the Cell Counting Kit-8 (CCK-8) method. The results showed a high aggregation of tumor cells on the 3D scaffold, which was suitable for long-term culture. Cytoskeleton staining and immunofluorescent protein staining were used to evaluate the degree of differentiation of tumor cells under 2D and 3D culture systems. The results indicated that 3D bioprinted scaffolds were more suitable for tumor cell expansion and differentiation, and the tumor cells were more aggressive. In addition, luteolin was time- and dose-dependent on tumor cells, and tumor cells in the 3D culture system were more resistant to the drug.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.331-337
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• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.273-276
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• 2005

Performance analysis of a solid oxide fuel cell/micro gas turbine hybrid system is conducted at design-point and part-load conditions and its results are discussed in this study. With detailed considerations of the heat and mass transfer phenomena along various flow streams of the SOFC, the analysis based on a quasi-2D model reasonably predicts its performance at the design-point operating conditions. In case of part-load operations, performance of the hybrid system to three different operation modes(fuel only control, speed control, and VIGV control) is compared. It is found that the simultaneous control of both supplied fuel and air to the system with a variable MGT rotational speed mode is the optimum choice for the high performance operation. And then, the dynamic characteristics of a solid oxide fuel cell are briefly introduced.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.347-353
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• 2001

A combined cycle, 'HYBRID', is emerging as a new power generation technology that is particularly suitable for the distributed power generation system, with high energy efficiency and low pollutant emission. Currently micro gas turbines and fuel cells are attracting a lot of attention to meet the future needs in the distributed power generation market. This hybrid system may have every advantages of both systems because a gas turbine is synergistically combined with a fuel cell into a unique combined cycle. The hybrid system is believed to become a leading runner in the distributed power generation market. This paper introduces a current plan associated with the development of the hybrid system which consists of a micro gas turbine and a solid-oxide fuel cell(SOFC).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.103-104
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.149-150
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• 2010

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1093-1099
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• 2009

Alternative energy sources such as renewable energy like solar power systems, wind power systems, or fuel cell power systems has been the rising issue in the electrical power system. This paper discusses an economic study analysis of fuel cells in the korean electricity market. It includes the basic concept of a fuel cell and the korean electricity market. It also describes the need of renewable energy and how the fuel cell is connected with the local grid. This paper shows the impact of production and recovering thermal energy of a grid-connected fuel cell power system. The profit maximization approach has been structured including electrical power trade with the local grid and heat trade within the micro-grid. The strategies are evaluated using a local load that uses electric and thermal power which has different patterns between summer and winter periods. The solution algorithm is not newly developed one, but is solved by an application called GAMS. Results indicate the need and usefulness of a fuel cell power system.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7435-7439
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• 2015

A failure of a cell to self destruct has long been associated with cancer progression and development. The fact that tumour cells may not instigate cell arrest or activate cell death mechanisms upon cancer drug delivery is a major concern. Autophagy is a mechanism whereby cell material can be engulfed and digested while apoptosis is a self-killing mechanism, both capable of hindering multiplication after cell injury. In particular situations, autophagy and apoptosis seem to co-exist simultaneously or interdependently with the aid of mutual proteins. This review covers roles of microRNAs and chemopreventive agents and makes an attempt at outlining possible partnerships in maximizing cancer cell death with minimal normal cell damage.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2834-2838
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• 2008

An free breathing proton exchange membrane fuel cell (PEMFC) was developed. This paper presents a study of the several effect on the performance of a fuel cell such as air flow rate, opening ratio, and cathode structures. Especially, an air flow rate is critical condition to improve the fuel cell performance. In this paper, we developed a synthetic jet micro air blower to supply high stoichiometric air. The synthetic jet actuation is usually generated by a traditional PZT-driven actuator, which consists of a small cylindrical cavity, orifices and PZT diaphragms. In comparison with free convection fuel cells, the forced-convection fuel cell which equipped synthetic jet micro air blower brings higher performance and stability for long term test. Also, power consumption of the synthetic jet micro air blower is under 0.3W. The results show that the maximum power density was $188mW/cm^2$ at $400mA/cm^2$. The maximum power density was higher 40% than power density of free convection fuel cell.