• KSBB Journal
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• 제9권4호
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• pp.428-435
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• 1994

Cell growth and production of ${\alpha}$-amylase, acetic acid and lactic acid were investigated in Bacillus amyloliquefaciens(ATCC 23350) flask culture with various carbon sources. Maximum dry cell density increased with increase in initial maltose concentration. Maximum dry cell density was the highest(1.4g/$\ell$) at 10g/$\ell$ of initial glucose concentration. With 10g/$\ell$ of initial glucose concentration, maximum specific cell growth rate was obtained. Among the various carbon sources maximum ${\alpha}$-amylase production was obtained with 149 unit/ml at 20g/$\ell$ of initial maltose concentration. With 5g/$\ell$ of initial maltose concentration, maximum ${\alpha}$-amylase production rate was obtained. By increasing carbon source concentration, acetic acid formation decreased. Acetic acid formation was higher in glucose than in maltose. By increasing carbon source concentration, lactic acid formation increased. Lactic acid formation was higher in maltose than in glucose.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제12권7호
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• pp.2939-2944
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• 2011

The performance and efficiency of a Molten Carbonate Fuel Cell system will improve with the aids of numerical simulations such as finite element analysis. For best simulation results, the virtual model must accurately reflect the actual model including the material properties. It is very difficult, however, to make a detailed numerical model of the stack that consists of hundreds of layers of unit cells composed of various materials like metal, ceramics, polymer, etc. Instead, a practical approach is to find a homogenized material property of the stack as a whole as an approximate replacement. In this paper, the compression ratio of a unit cell is introduced, and a new method is proposed to estimate the homogeneous material properties for both the active and the manifold regions of the stack under the assumption that the compressive deformation occurs only at the separators and matrices in the unit cells. The estimated properties are applied successfully to simulating an actual stack.

• Transactions on Electrical and Electronic Materials
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• 제8권6호
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• pp.286-288
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• 2007

The research and development for the solid oxide fuel cell have been promoted rapidly and extensively in recent years, because of their high efficiency and future potential. Therefore this paper describes the manufacturing method and characteristics of anode electrode for solid oxide fuel cell, by the way, Ni-YSZ materials are used as anode of solid oxide fuel cell widely. In order to reduce production costs, we have fabricated single solid oxide fuel cell by doctor blade and screen printing method. Disk-type planar solid oxide fuel cell with an effective electrode area of about $7cm^2$ were fabricated and run for 500 h to investigate cell performance. The current density at a voltage of 0.7 V was $850mA/cm^2$.

• Biomedical Science Letters
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• 제2권2호
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• pp.211-222
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• 1996

The conceptus which are resulted by mating between two genetically non-identical partners can be considered to be an allograft to the mother science which is not rejected by the mother's immunological attack. The present studies have been, therefore, attempted in order to elucidate the mechanism by which protection of the fete-placental allograft, between the C3H/HeJ female mouse and DBA/2 male mouse occurred. For this purpose, firstly systemic immunity was investigated by measuring T and B lymphocytes subsets. Natural killer cell activity in maternal splenic tissue and by observing the effects of pregnancy serums, progesterone and hCG on immune systems. Secondly, local immunity also investigated by measuring T lymphocytes subsets, natural killer cell activity in lymph nodes draining the uterus. The subsets of Thy-1.2$^+$ cells and L 3T4$^+$ cells decreased slightly while the subsets of Ly2$^+$ cell increased significantly compared with those of the control group beyond the mid-gestational stage. The subsets of B cell gradually in-creased from the mid-gestational stage untill delivery. The natural killer cell activity in the maternal splenic tissue significantly increased during the period of 5th to 8th day of gestation. The natural killer cell activity was significantly suppressed by the pregnancy serums and non-pregnant serums compared with those of serum-free group. The treatment of hCG significantly suppressed natural killer cell activity in the dose dependent manner (1 unit/ml-1000 unit/ml) while pro-gesterone increased the natural killer cell activity at phamarcological dose only. In the lymph nodes draining the uterus, the subsets of Thy-1.2$^+$ cells significantly increased during the period of implantation and L3T4$^+$ cell subsets slightly increased during the mid-gestational stage. The subsets of Ly2$^+$ cell increased significantly during the mid-gestational stage, but decreasing slightly be-fore delivery. The natural killer cell activity was significantly elevated after the implantation period in the lymph nodes draining the uterus. The natural killer cell activity of the lymph nodes draining the uterus was higher than those of splenic tissue during the same periods of gestation. It is therefore, concluded that during the pregnancy, the phenomena which the fete-placental allograft has not been rejected and rather protected from the maternal immunological attack might be due to local immune suppression in fete-maternal interface tissues rather than systemic immune suppression. And the subsets of Thy-1.2$^+$ cells and L3T4$^+$ cells mainly contribute to accepting allograft in early stage of pregnancy, while the subsets of Ly2$^+$ cell and the subsets of B cell increased significantly compared with those of the control group beyond the mid-gestational stage, so their role in systemic immunity and local immunity gradually increased from the mid-gestational stage until delivery.

• Journal of the Korean Ceramic Society
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• 제42권4호
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• pp.269-275
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• 2005

We analyzed the unit cell performance against the cathode porosity, which is supposed to be closely related with active sites for the cathode reaction. In order to fabricate the unit cells with different porosity in the cathode layer we changed the mixing ratio of fine and coarse LSCF cathode powders. The final porosity of each cathode layer was 14, 23, 27, $39\%$ respectively. According to the electrochemical analysis of unit cell performance via DC current interruption and AC impedance method, the electrodic polarization resistance was diminished as the cathode porosity increased. The decrease of polarization resistance was attributed due to the increase of active reaction sites and the enhancement of overall unit cell performance could be explained in the same line.

• Journal of the Korean Ceramic Society
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• 제41권10호
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• pp.777-782
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• 2004

In this research, $5\times5cm^2$ unit cells were fabricated via liquid condensation process and uniaxial pressing followed by the screen printing of electrolyte and cathode layer. The SOFC stack was assembled with unit cells, gasket-type sealant and metal interconnect. The stack was designed to have a single column with internal-manifold and cross-flow type gas-channels. The SOFC stack produced 15 W, which is $50\%$ of the maximum power being expected from the maximum power density of the unit cell. Controlling factors for the proper operation of the SOFC stack and other designing factors of stack manifold and gas channels were discussed.

• Proceedings of the KIPE Conference
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.79-80
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• 2014

In this paper, to make sure that the photovoltaic solar cell module of the system can be normal for output in each solar cell module, input and output unit is installed in the bypass device, and then through the voltage and current monitoring to determine abnormality of the solar cell module, in the case of abnormal occurring, the bypass device can be pass to the next solar module of the serial structure.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 한국식물생명공학회 2002년도 춘계학술대회
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• pp.159-159
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• 2002

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 한국식물생명공학회 2002년도 춘계학술대회
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• pp.160-160
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• 2002

• BMB Reports
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• 제49권12호
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• pp.655-661
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• 2016

Polymer brush is a soft material unit tethered covalently on the surface of scaffolds. It can induce functional and structural modification of a substrate's properties. Such surface coating approach has attracted special attentions in the fields of stem cell biology, tissue engineering, and regenerative medicine due to facile fabrication, usability of various polymers, extracellular matrix (ECM)-like structural features, and in vivo stability. Here, we summarized polymer brush-based grafting approaches comparing self-assembled monolayer (SAM)-based coating method, in addition to physico-chemical characterization techniques for surfaces such as wettability, stiffness/elasticity, roughness, and chemical composition that can affect cell adhesion, differentiation, and proliferation. We also reviewed recent advancements in cell biological applications of polymer brushes by focusing on stem cell differentiation and 3D supports/implants for tissue formation. Understanding cell behaviors on polymer brushes in the scale of nanometer length can contribute to systematic understandings of cellular responses at the interface of polymers and scaffolds and their simultaneous effects on cell behaviors for promising platform designs.