• New & Renewable Energy
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• v.3 no.1 s.9
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• pp.60-67
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• 2007

Catalyst coated membrane [CCM] type and catalyst coated substrate [CCS] type of membrane electrode assembly [MEA] were manufactured and evaluated their performance. Degradation test were conducted to find the difference of long term stability in two types of MEA and the factor for performance degradation problem occurred. Performance degradation test of single cell in two different types of MEA were carried out when current density was $200mA/cm^{2}$. The degradation test had proceeded for 230 hours and performance degradation was checked by I-V curve and impedance measurement at regular intervals. Also, MEA before/after operation and changes of catalyst layer were characterized by SEM, TEM, and XRD. Maximum power density of CCM type was higher than that of CCS type. Meanwhile, an increase of particle size of catalyst and an increase of impedance resistance after long term operation were observed. In the case of using CCM type MEA, the performance was deteriorated 38% of initial performance. In the case of using CCS type MEA, the performance was deteriorated 43% of initial performance. In consideration of difference of initial performance, performance of CCM type is higher than that of CCS type but both types had similar problems during degradation test.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.117-123
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• 2021

This study aims to analyze working hours of sprinkler heads when a fire occurs at an indoor gymnasium while sprinkler heads are installed in division of standard response type, special response type, and earlier response type. The fire scenario was designed under the assumption that the fire started from overheating of a heater in the indoor gymnasium has transferred on to a couch to spread. The analysis on the operation time of the standard response type sprinkler head, the special response type sprinkler head and the early response sprinkler head was conducted. The result showed that, in case of fire in a gymnasium, the time for opening of the heat sensor due to the heat from the fire varies by the type of the sprinkler head. When a special response type sprinkler is installed, it worked below the assessment standards. When an early response sprinkler head is installed, it worked appropriately according to assessment standards. Based on the results, we found that sprinkler heads will work properly when installed according to design relevant to laws and regulations. This means that there is a limit in installation of sprinkler heads based on the existing law-based design as for indoor gymnasiums. Again, we conclude that if sprinkler heads are installed based on design made through laws and regulations, more time will be needed for operation, making it highly likely to fail to stop a fire at an earlier point of time.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.2
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• pp.87-96
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• 1993

Because of the complexity, nonlinearity and long-time delay of power plant, the star-up operation of a fossil power plant is very difficult to automate. So the start-up operation is always carried out by the skilled human operators, who utilize their knowledges and experiences for the predesigned start-up schedules and procedures. In this paper, a fuzzy logic controller is designed for the start-up operation of the power plant. And the operators experiences are modeled in terms of fuzzy sets and variables. To validate the controller, a drum-type boiler of the Seoul Power Plant is constructed via the signal flow diagram. Using the model, the suggested automatic start-up operation is verified, and the results are also presented.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.777-781
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• 2014

The current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) using series connected two coils with twice triggering operation, which consists of series connected two coils and two superconducting (SC) modules with the inserting resistance, was analyzed. The feature of the suggested SFCL is that it can limit the fault current by triggering either one SC module or two SC modules comprising the SFCL depending on the amplitude of the fault current. To verify the current limiting operation of the suggested SFCL, the short-circuits in the fault location with the different fault currents were tested and its useful operations were described through the analysis on the tested results.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.21-29
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• 2003

Boosting of engine power by using Turbo- or Super-charger is a solution to comply with $CO_2$-regulation in Europe. Turbo-charger is now playing a major role in the field of charging system thank to its technical advantages such as no demand of operation power from engine. A mechanically driven Super-charger, however, is now popular due to quick speed response to change of the driving mode-high engine torque even at low engine speed. Since Super-charger needs operation power from engine, it is difficult to improve its relatively higher fuel consumption than that of Turbo-charger. This negative point is still an obstacle to the wide use of Super-charger. This study aims to develop power control concept to achieve the minimization of operation power when it is not necessary to charge at idling or part load driving condition. A screw type Super-charger was modified in design partially and adapted an internal bypass valve and a bypass tube to control charging pressure at part load. The various control concepts show a possibility to reduce operation power of Super-charger and result in improvement of fuel consumption.

• Journal of Chest Surgery
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• v.15 no.3
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• pp.346-354
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• 1982

A Complete transposition of the great arteries combined with V.S.D, A.S.D, dextrocardia, and P.S is a rare congenital anomaly. The patient was a 10 year-old female whose complaints were frequent URI, exertional dyspnea, and cyanosis at rest since birth. Cheat X-ray films showed Dextrocardia ; situs inversus, moderate cardiomegaly, and Characteristic egg-shape heart shadow. E.K.G, Echocardiography, Cardiac Catheterization, and Angio-Cardiography were performed. Open heart Surgery was done under diagnosis of d-TGA, Dextrocardia, V.S.D, A.S.D, and P.S. At the time of Operation, Dextroeardia, T.G.A, Secndum type A.S.D, A.S.D, and P.S. At the time of Operation, Dextroeardia, T.G.A, Secndum type A.S.D. ($2.0{\times}2.0cm$. in diameter), V.S.D. type II ($1.5cm{\times}1.5cm$ in diameter), and pulmonary valvular stenosis were noted. Mustard operation using pericardial Baffle in the atrium for T.G.A. was perforsned. Teflon patch graft for closure of V.S.D. through tricuspid orifice and pulmonary Valvulotomy through pulmonary arteriotomy were performed. The post-op, low cardiac output Syndrome and dysrhythmicawere developed till Postoperative day #7, so that was controlled by inotropic and antiarrhythmic agents. After that, patient's conditions were Uneventful.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.353-358
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• 2001

Turbo-charging or Super-charging has been used to boost engine power for Gasoline Engine and Diesel Engine came to the world at the beginning of $20^{th}$ century. So far Turbo-Charger has enjoyed a high reputation in the charging filed for its technical advantages such as no demand of operation power from engine and an excellent charging effect in the event of a static operation at mid- and high engine speed. A mechanically driven Super-Charger, however, is now emerging in order to meet demands of the age of speed such as high engine power for a quick change of the driving mode - high engine torque even at low engine speed. Since Super-Charger needs driving power from engine, it cannot improve its relatively higher fuel consumption against that of Turbo-Charger. This negative point is still an obstacle to the wide use of Super-Charger. Super-Charger using Screw-type compressor which has already had a considerable base in air compressor market will fulfill this purpose of improving fuel consumption by minimizing operation power owing to no charging at idling or partially loading driving. This study aims to develop power control concept to achieve this minimization of operation power.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.509-511
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• 1994

Cycloconverters can be classified into two types by the main circuit configuration. One is the non- circulating current type required the dead time the other is circulating current type which has the circulating current reactors. The switching devices were highly stressed by the load voltages during dead time on non-circulating current type operation and the circulating currents on circulating current type operation. The overcome those problems, this paper proposes the switching patterns for the partial and the non circulation current type. The PWM methods, which are saw wave comparing method and load current integrating value comparing method, are presented.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.897-902
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• 2007

The turnover-type sluice gate is typically actuated by the open circuit hydrauic system since the single-rod cylinder is used rather than the double-rod cylinder. However, here the closed circuit hydrauic system is applied for the operation of turnover-type sluice gate for the purpose of convenient operation. The closed circuit hydraulic system of turnover-type sluice gate is composed of a bi-directional pump, single-rod cylinders, pilot operated check valves, check valves and a counter balance valve. The usefulness of the closed circuit hydraulic system is verified for the several operational conditions by the computer simulations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.68-73
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• 2012

In this paper, the fault current limiting characteristics of a flux-lock type superconducting fault current limiter (SFCL) with peak current limiting function were analyzed through its short-circuit tests. The setting condition for the peak current limiting operation was derived from its electrical equivalent circuit, which was dependent on the inductance ratio between the third coil and the first coil. Through the analysis on the short-circuit tests for the flux-lock type SFCLs with the different inductance ratio between the third coil and the first coil, the setting value for the peak current limiting operation of the flux-lock type SFCL with peak current limiting function could be confirmed to be adjusted with the variation of the inductance ratio between the third coil and the first coil.