• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3001-3006
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• 2008

Recently, the internal combustion engines have focused on reducing both the CO2 emissions in order to cope with severe regulations for greenhouse effect. Therefore, various new technologies have been developed in many countries. Among them, the cooling system is spotlighted because it has great effect on fuel efficiency. However, the present engine cooling system is almost same as one of the 50 years ago. The needs for high performance and compact size make it important to improve engine cooling system, down-sizing and control method of coolant flow. Thus, low fuel consumption technology such as control and synthetic management of cooling system was necessary to satisfy with these needs. In this study, we applied electric thermostat to improve the fuel economy. The fuel consumption was compared after driving FTP-75 mode on both conditions which were with a conventional wax thermostat and with a electric thermostat. The coolant temperature of opening the electric thermostat is higher.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.2
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• pp.19-27
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• 2002

The smokeless liner, was required to propulsion system of gas generator, was developed by appling oxamide as a filler and HTPB system as a binder. Relative quantities of smoke produced during burning of liner by propellant combustion was measured by using smoke chamber. The smoke of the smokeless liner containing 50% of oxamide as filler was reduced to 1/10 as compared with conventional liner containing silica as filler. This result was showed by ground test of gas generator.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.122-128
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• 1999

CARS(Coherent anti-Stokes Raman Spectroscopy) temperature measurement under engine-like condition was validated by measuring unburned gas temperatures of premixed propane-air flame in a constant volume combustion chamber. The measured temperatures were compared with predictions of 2 zone flame propagation model. End-gas temperatures were measured were measured by CARS technique in a conventional 4 cylinder DOHC spark-ignition engine fueled with PRF 80. Cylinder pressure was measured simultaneously with CARS signal and used as a parameter on fitting CARS spectrum to library of theoretical spectra. There was a good agreement between the measured temperature and adiabatic core temperature calculated from measured cylinder pressure. Significant heating by pre-flame reaction in the gas was observed in the late part of compression stroke.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.112-118
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• 1996

When fossil fuels are burned they produce CO gas because of incomplete combustion. If the CO gas reacts with the hemoglobin in the red blood cells, it may result in death or sequelae. Generally, the CO gas is eliminated in the form of the $$$CO_2$ gas by the oxidation reaction over the platinum catalyst. In this study, the electrochemical CO removal was investgated by using the solid electrolyte cell reactor, the type of which was represented as reactants$/Pt/Y_2O_3-ZrO_2/Pt/Air$. If the overpotential was applied to the platinum working electrode, the conversion could be changed with the overpotential applied. It was found that the oxidation rate could be increased 2.8 times higher than that of the normal condition, i. e. under open circuit conditions when $P_{co}/P_{O_2}$ was 0.5 and overpotential was 0.9V. From these results, it is concluded that the reactor used in this study is more efficient than conventional catalytic reactors.

• Journal of Sensor Science and Technology
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• v.25 no.6
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• pp.394-398
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• 2016

In this paper, a fire detection system based on quantitative risk estimation is presented. Multiple sensors are used to build a comprehensive indicator that represents the risk of fire quantitatively. The proposed fire risk estimation method consists of two stages which determines the occurrence of fire and estimates the toxicity of the surveillance area. In the first stage, fire is reliably detected under diverse fire scenarios. The risk of fire is estimated in the second stage. Applying Purser's Fractional Effective Dose (FED) model which quantitates harmfulness of toxic gases, the risk of the surveillance area and evacuation time are calculated. A fire experiment conducted using four different types of combustion materials for the verification of the system resulted in a maximum error rate of 12.5%. By using FED calculation and risk estimation methods, the proposed system can detect various signs of fire faster than conventional systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.120-123
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• 2000

This paper reports a newly developed sol-gel process to synthesize dense YBCO thick films with $BaTiO_3$ additives using electrophoretic deposition and metal alkoxide sol/particle suspension, which we successfully produce dense $YBCO+BaTiO_3$ ceramics at a rather low temperature, compared with the sintering temperature used in conventional methods. The thick films of HTS were prepared by electrophoretic deposition, using pre-sintered powder with barium titanate addition in the form of $BaTi(OR)_6$ solution in suspension for electrophoresis. The conditions for applied voltage and deposition times for electrophoretic deposition of HTS thick films were studied in detail.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.323-323
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• 2015

In recent years, increasing concerns of environmental issues of global warming and limitations of conventional energy resources have resulted in extensive researches into energy harvesting from unused energy. Thermoelectric generation (TEG) is a promising technology for waste heat to power, and various kinds of applications are possible if a waste heat source meets the requirements of TEG operation. In terms of commercialization, economic feasibility is important for an emerging technology like TEG. In this study, economic analysis was conducted for the application of TEG on various sources of waste heat.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.814-819
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• 2000

The progress in the field of electronic materials has been especially significant for applications involving a range of electrical properties. Its importance is increasing with the increasing demand for integrated circuits. The sol-gel technique has been used for many years, and the metal alkoxides have featured prominently as source materials. The method consist of making a homogeneous solution of the component metal alkoxides in a suitable solvent, usually the parent alcohol; and then causing the hydrolysis under controlled conditions to produce a gel containing the hydrated metal oxide. The gel is then dried, and fired to produce a ceramic or glassy material at a temperature much lower than that required by the conventional melting process. This project consists of important theoretical considerations, processing techniques and applications related to electrophoresis derived thin films. In the electrophoretic process a metal alkoxide solution is gelled through hydrolysis-polymerization and converted the gel thin layer to an oxide by heating at relatively low temperatures.

• Journal of Hydrogen and New Energy
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• v.12 no.4
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• pp.277-285
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• 2001

We developed a compact, 10 kWe, purifier-integrated reformer which supplies hydrogen for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by palladium alloy membrane and catalytic combustion by noble metal coated wire-mesh catalyst were combined with the conventional methanol steam reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems. In this system, steam reforming, hydrogen purification, and catalytic combustion take place all in a single reactor so that the whole system is compact and easy to operate. The module produces $8.2Nm^3/hr$ of 99.999% or higher purity hydrogen with CO impurity less than 10 ppm, which is equivalent to 10 kWe when PEMFC has 45 % efficiency. Thermal efficiency of the module is 81 % and the power density of the module is 1.6 L/kWe. As the results of experiments, cold-start time has been measured about 20 minutes. Response time of hydrogen production to the change of the feed rate has been within 1 minutes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.21-27
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• 2015

In order to meet the current emission regulations (EURO-6), it is necessary to significantly reduce $CH_4$ and $NO_X$ emissions. This study investigated the effect of a reduction in the valve overlap on the combustion and emission characteristics of a hydrogen-compressed natural gas engine under a part-load operating condition. The combustion and emission characteristics were analyzed for each fuel using the original camshaft and an altered camshaft with reduced valve overlap. The results showed that the thermal efficiency was decreased and the fuel flow was increased when using the altered camshaft. The $CO_2$ and $CH_4$ emissions were increased as a result of the reduced thermal efficiency. Under lean operating conditions, the $NO_X$ emission was decreased compared with one of the conventional camshaft. Thus, under the same fuels and operating conditions, it had a harmful influence on the emission characteristics and thermal efficiency.