• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.1
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• pp.65-70
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• 2013

A 0.18-${\mu}m$ 3.3 V grounded-gate NMOS (GGNMOS) I/O cell array for timing controller (TCON) application is proposed for improving electrical overstress (EOS) robustness. The improved cell array consists of 20 GGNMOS, 4 inserted well taps, 2 end-well taps and shallow trench isolation (STI). Technology computer-aided design (TCAD) simulation results show that the inserted well taps and extended drain contact gate spacing (DCGS) is effective in preventing EOS failure, e.g. local burnout. Thermodynamic models for device simulation enable us to obtain lattice temperature distributions inside the cells. The peak value of the maximum lattice temperature in the improved GGNMOS cell array is lower than that in a conventional GGNMOS cell array. The inserted well taps also improve the uniformity of turn-on of GGNMOS cells. EOS test results show the validity of the simulation results on improvement of EOS robustness of the new GGNMOS I/O cell array.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.510-511
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• 2008

Fuel cell is a modular, high efficient and environmentally energy conversion device, it has become a promising option to replace the conventional fossil fuel based electric power plants. The high temperature fuel cell has conspicuous feature and high potential in being used as an energy converter of various fuel to electricity and heat. And, 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 high temperature widely. So in this experiments, we investigated the optimum content of Ni, by the impedance characteristics, overvoltage. As a result, the performance of Ni-YSZ anode(40vol%) was better excellent than the others.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3377-3382
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• 2007

In proton exchange membrane fuel cell, the heat is generated at the catalyst layer as result of exothermic electrochemical reaction. This heat increases temperature of gas diffusion layer and membrane whose conductivity is very sensitive to humidity, function of temperature. So it is very important to analysis heat transfer through fuel cell to maintain temperature at specified range. In this paper numerical simulation was done including reversible, irreversible, ionic resistance, water formation loss to source term of energy equation. Results show that irreversible and water formation loss contributes mainly to energy source term and as current density increases, all of energy source terms become increased and Nusselt number is increased as results of more heat generation. Particularly irreversible loss is found to be predominant among the all energy source and water formation at cathode channel influences the temperature distribution of fuel cell greatly.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1361-1369
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• 2003

Design performance of hybrid power generation systems, comprised of a gas turbine and an atmospheric pressure molten carbonate fuel cell, has been analyzed. Two different configurations were analyzed and performances were compared. A reference calculation was performed for the design condition of a system under development and simulated results agreed well with the published data. Performances were analyzed in terms of main design parameters including turbine inlet temperature, operating temperature of the fuel cell and pressure ratio. Also examined were the effects of fuel utilization factor and heat exchanger effectiveness. It was found that the relationship between the turbine inlet temperature and the fuel cell temperature should be critically examined to evaluate achievable design performance. Considering current state of the art technologies, a system with the combustor located before the turbine could achieve higher efficiency and specific power than the other system with the combustor located after the turbine.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.296-296
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• 2016

ITO films doped with a small amount of high-permittivity materials not only retain the basic properties of ITO films but also improve some of their properties. We report the highly conductive and transparent (ITO:Zr) films with various substrate (RT to 300oC) temperatures on glass substrate for the HIT solar cell applications. We observed a decrease in sheet resistance from 36 to $11.8{\Omega}/{\Box}$ with the increasing substrate temperature from RT to 300oC, respectively. The ITO:Zr films showed also lowest resistivity of $1.38{\times}10-4{\Omega}.cm$ and high mobility of 42.37cm-3, respectively. The surface and grain boundaries are improved with the increase of substrate temperature as shown by SEM and AFM surface morphologies. The highly conductive and transparent ITO:Zr films were employed as front electrode in HIT solar cell and the best performance of device was found to be Voc = 710 mV, Jsc = 33.70 mA/cm2, FF = 0.742, ${\eta}=17.76%$ at the substrate temperature of $200^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.303-306
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• 2009

High temperature solid oxide fuel cells (SOFCs) offer a clean, pollution-free technology to electrochemically generate electricity at high efficiencies. Solid oxide fuel cells in several different designs have been investigated; these include planar and tubular geometries. The tubular type cell is widely researched due to it have advantages about thermal expansion and sealing issues. Unfortunately, lab scale tubular cell for testing has thermal expansion and sealing problems. The previous Jig for lab scale tubular cell testing has many sealing problems. When we feed fuel gas to jig inlet, ceramic glue sealant has amount of gas expansion pressure, because temperature of feeding gas changes ambient temperature to high temperature ($700{\sim}900^{\circ}C$). Furthermore, when we carry out long time test, something like degradation test, crack of ceramic glue sealant due to weakness of mechanical properties can make stop working the test. Additionally, we reduce setting process for assembling, because micanite is not required drying or debinding process.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.220-224
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• 2009

The effect of addition of single and binary additives on the performance of dye-sensitized $TiO_2$ solar cells based on 1,2-dimethyl-3-propylimidazolium iodide (DMPII) in ethylene carbonate (EC) and gamma-butyrolactone (GBL) has been evaluated at different cell temperatures in the $30-120^{\circ}C$ range. The electrolyte containing a single additive, 2-(dimethylamino)-pyridine (DMAP) showed best performance, which showed further enhancement for an electrolyte containing binary additives, DMAP and 5-chloro-1-ethyl-2-methylimidazole (CEMI) in equal molar ratio. The performance of the dye sensitized solar cell (DSC) based on electrolyte containing binary additives were found to be better than an acetonitrile based electrolyte. The dependence of different photovoltaic parameters (Voc, Jsc, ff, n) of the DSC upon temperature has been studied over the $30-120^{\circ}C$ range and only a small decrease in conversion efficiency has been observed. Thus the electrolyte containing binary additives (DMAP, CEMI) in EC/GBL solvent and show better performance in the investigated temperature range ($30-120^{\circ}C$).

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.149-149
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• 2009

Generally, Nafion ionomer is used in the polymer electrolyte fuel cell (PEFC) electrodes to achieve high power density. At the high temperature operation of PEFC, however, ionic conductivity of Nafion remarkably decreased due to the evaporation of water in Nafion polymer. Recently, many researchers have focused on using the Ionic Liquids(ILs) instead of water in Nafion polymer. ILs have intrinsic properties such as good electrochemical stability, high ionic conductivity, and non-flammability. Especially, ILs play a crucial role in proton conduction by the Grottuss mechanism and act as water in water-free Nafion polymer. However, it was found that the ILs was leached out of the polymer matrix easily. In this study, we prepared membrane electrode assemblies with various contents of ILs. The effect of ILs in the electrode of each designed was investigated by a cyclic voltammetry measurement and the cell performance obtained through a single cell test using H2/Air gases. Electrodes with different contents of ILs in catalyst layer were examined at high temperature and low humidified condition.

• Archives of Pharmacal Research
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• v.28 no.2
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• pp.220-226
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• 2005

Temperature and medium composition were changed with the aim of increasing growth and erythropoietin (EPO) production in EPO-producing Chinese hamster ovary (CHO) cells. We used the CHO cell line, IBE, and its derivative, CO5, which over-expresses the first two enzymes of the urea cycle, carbamoyl phosphate synthetase I (CPS I) and ornithine transcar-bamoylase (OTC). When supplements were added to the medium at $33\;^{\circ}C$, the growth of IBE and CO5 cells increased by $27\%\;and;26\%$, respectively and the maximum yield of EPO was increased by $40\%$ in both cell lines. The absolute EPO concentration in the CO5 cells was always $55{\sim}60\%$ higher than in the IBE cells. In addition, when the two cell lines were continuously cultured with supplements at $33\;^{\circ}C$ until their growth rates approached those at $37\;^{\circ}C$, the growth rates of both IBE and CO5 cells increased by $54\%$ and their maximum EPO levels increased by up to $73\%\;and\;56\%$, respectively. Therefore, the growth and EPO expression levels of CO5 cells increased 2.2-fold and 2.6-fold, respectively, compared to those of the IBE cells. These results indicate that adaptation to lower temperature as well as medium supplementation could be important for improving cell growth and EPO production.

• Journal of the Korean Ceramic Society
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• v.43 no.9 s.292
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• pp.552-557
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• 2006

A low temperature processing route for fabricating porous SiC ceramics by carbothermal reduction has been demonstrated. Effects of expandable microsphere content, sintering temperature, filler content, and carbon source on microstructure, porosity, compressive strength, cell size, and cell density were investigated in the processing of porous silicon carbide ceramics using expandable microspheres as a pore former. A higher microsphere content led to a higher porosity and a higher cell density. A higher sintering temperature resulted in a decreased porosity because of an enhanced densification. The addition of inert filler increased the porosity, but decreased the cell density. The compressive strength of the porous ceramics decreased with increasing the porosity. Typical compressive strength of porous SiC ceramics with ${\sim}70%$ porosity was ${\sim}13 MPa$.