• Transactions of the Korean hydrogen and new energy society
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• v.21 no.2
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• pp.111-116
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• 2010

In this study, the structural analysis was performed to optimize the membrane humidifier with hollow fiber membrane for polymer electrolyte membrane fuel cell system. The main design factors were considered by evaluating the humidifying performance according to various structural parameters such as packing density and length. The effects of operation conditions of membrane humidifier were also elucidated experimentally. Results imply that there are optimum points for the packing density and length of humidifier. It was also found that among operation conditions, relative humidity of wet exhaust gas and temperature of dry inlet gas have major effects on the humidifying performance.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.291-296
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• 2011

This paper presents energy self-sufficiency simulated in municipal wastewater treatment plants (WWTPs) by adopting solar energy production systems that vary with installation conditions. Relative to the national average energy consumption in WWTPs, the employment of 100 kW photovoltaics (PVs) was simulated to achieve 2.75% of energy self-sufficiency. The simulated results suggested that the installation of PVs toward South or South west would produce the highest energy self-sufficiency in WWTPs. When super-hydrophilic coating was employed in the conventional PVs, 5% of additional solar energy production was achievable as compared to uncoated conventional PVs. When 100 kW of PVs were installed in a future test-bed site, Kihyeung Respida located in Yougin, Sourth Korea, the energy self-sufficiency by solar energy was simulated to be 1.77% (2010). The simulated energy self-sufficiency by azimuth(direction) will be useful reference for practitioners in designing the solar PV systems in the WWTPs.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.7 no.1
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• pp.10-16
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• 2011

Performance of ground-source heat pumps (GSHPs) is mainly affected by ground heat exchangers which makes up more than 40% of construction cost. Exact construction and grout as backfill are important, because it is difficult to repair after being installed. As grout materials, bentonite grout material and cement material are used In this paper, thermal conductivity according to mix proportion of cement grout has been experimentally studied. Some variables were set to evaluate thermal conductivities according to change in cement content, unit water ratio, mass per volume of fresh mortar, and aggregate types. From the experimental analysis, high performance cement grout has been proposed.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.450-454
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• 1994

From a point of view in energy saving and improvement of productivity, inverter for large power induction motor drive is very important. In this thesis, we developed high voltage inverter for large power induction motor drive. We experimented the inverter with R-L series load, successfully, and are going to do the field test in the real plant.

• Natural Product Sciences
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• v.7 no.2
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• pp.60-62
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• 2001

Ulmus davidiana, Formitella fraxinea, and Aloe vera extracts were detected to have inhibitory effects against topoisomerase I at treatment of $5{\mu}g$. Ulmus davidiana and Aloe vera extracts were found to show inhibitory effect similar to camptothecin, Formitella fraxinea extract was found to have weak activity. We also found the potential use of those extracts as a radiation sensitizer. Radiosensitizing effect at combination treatment was increased more than 2 times at single treatment of radiation, Ulmus davidiana or Formitella fraxinea extracts. Ulmus davidiana and Formitella fraxinea extracts were found to have significant radiosensitizing effect on test tumor cell line. But, Aloe vera extract was not detected to have activity as a radiosensitizer. Ulmus davidiana and Formitella fraxinea extracts are potent radiosensitizers on tumor cell lines and should be considered for further study of active compounds.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.626-629
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• 1997

The urban transit propelled by single sided linear induction motor(SLIM) have been in stage for practical application. Also, the use of the linear induction motor in traction systems enables large forces to be achieved without friction between wheels and rails. In this paper we discuss the linear induction motor (LIM) drive system (300KVA) for magnetic levitation vehicles.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1220-1224
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• 2008

Because of the high airtightness and insulation of the building, indoor environment has been largely polluted resulted from insufficient ventilation and occurrence of new air pollutant. These factors have made worse indoor air quality and caused symptoms of the SHS(Sick House Syndrome), MCS(Multi Chemical Sensitivity). The purpose of this study is to present the fundamental strategies for improving the Indoor Air Quality(IAQ) in newly-constructed apartment buildings. To investigate the concentration of indoor air pollutants such as Formaldehyde and VOCs, the field measurement were conducted.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.867-869
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• 1993

In generally Boost Converter is used for Fuel Cell System. Because the output voltage of fuel cell is too small and greatly depends on the load condition, Boost Converter are required to boost and regulate the Fuel Cell voltage for per conversion efficiency. In this Paper, 6-phase Boost Converter is used to boost the Fuel Cell Voltage and regulate the output voltage. Multi phase converter hag some advantages such as low ripple and filter sine. About the Peak Current Control and compare of the Ripple Current of Boost Converter, we have studied.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2004.11a
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• pp.40-44
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• 2004

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.56-56
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• 2011