• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.69-73
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• 2004

The flash point is one of the most important combustible properties used to determine the potential for the fire and explosion hazards of industrial material and the fire point is the temperature of the flammable liquid at which there will be flaming combustion, sustained 5 seconds in response to the pilot flame. In this study, the flash point and fire point were measured to present raw data of the flammable risk assessment for alcohols, using Tag open-cup apparatus(ASTM D 1310-86). The measured values were compared with the calculated values based on 0.78 times stoichiometric concentration. The values calculated by the proposed equations were in good agreement with the measured values.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.10
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• pp.94-101
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• 2011

The proper installation of SPD and the evaluation of the SPD protection distance are basic steps for the effective protection measures of apparatus against surges within a structure. A novel method for installing SPD on the conventional distribution board without any modification was proposed and it's effectiveness was evaluated by experiments. Also, the transient overvoltage occurred across the power line from the SPD to the load was simulated with EMTP software to see how different the protection distances affecting the magnitude of the transient overvoltage. As evaluated, the effective protection method of apparatus against surges, coordinated SPD protection system is suggested as a proper measure to protect within the apartment.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.699-701
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• 2001

The expert system monitoring and diagnosing 765kV power apparatus was described in this paper. To develop this expert system, we studied the knowledge bases and data bases for 765kV transformer and GIS. In order to make the reliable inference of knowledge base and the good MMI(Man Machine Interface), the data bases were consisted of the tables of power apparatus information, limit level value, measured input data, inference result and diagnosis result. The knowledge base had various rules to infer the conditions of transformer and GIS. We applied both the forward chaining and backward chaining methods to these rules of system for good inferences. This paper describes the applied methods for expert system. Also, this developed system was tested with dissolved gas analyzing result and the result was shown.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1858-1862
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• 2005

Stepping motor normally operates without feedback and may loss the synchronization. This problem can be prevented by using positional feedback. This paper introduces one method for closed loop control of stepping motor and a method for combining full-step control and micro-step control. This combination controlling apparatus can perform position control with high accuracy in a high speed, so that it will not suffer from vibration (or hunting) problem when stopping motor. Controlling apparatus contains a position counter block for detecting rotor position of stepping motor, a driving block for supplying current to windings of stepping motor, a control block for comparing output signal of position counter block with command position (desired position) and outputting current command signal based on deviation between current position and command position of rotor. To output current command signal, the control block refers to a sine wave data table. This table contains value of duty cycle of Pulse Width Modulation signal. As the second object of this paper, the process of building this data table is also presented.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.1
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• pp.64-70
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• 2008

This paper briefly discusses the main sources of errors and their solutions for measuring hydrogen uptake from gas phase by the Sieverts technique. Correction of volumetric errors of apparatus, density of hydrogen storage material, estimation of temperature gradient are investigated. Systematic errors and the change of density of the host material according to the pressure have been the subject of much controversy in recent years. We considered the standard ball calibration, temperature gradient distribution, pretreatment of hydrogen storage materials to minimize errors. We could lessen the miscalculations after applying those methods to Equilibrium pressure-composition isotherm data.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1171-1174
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• 2005

This thesis provides a new digital convergence method and apparatus which uses area photo sensor and new analog to digital algorithmic to identify the correct digital pattern position factor of the projection system. This method and apparatus can be applied to the convergence correction in a TV receiver with a display that comprises a display screen with photo sensors positioned adjacent to screen edges. It also can be applied to the manufacture process detection of the projection system to adjust the associative convergence parameter. In this paper, demonstrate how this convergence detecting algorithmic was implemented with four area photo sensors of special designed pattern to the rear projection CRT TV.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.410-412
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• 2002

So far, electricity rate under the midnight hour incorporates policy consideration and maintains fixed irrespective of generation cost. Therefore, the promotion of midnight power apparatus has been rapidly increased due to increasing difference in substitute heating cost. This paper estimates the power supply cost during midnight times and analyzes the rate mechanism which can promote economic midnight power apparatus. In addition it provides the alternative on the direction of policy after the restructuring.

• The Korean Journal of Ceramics
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• v.4 no.1
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• pp.5-8
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• 1998

Flat belt(FB) type high pressure apparatus has been succesfully utilized in various high pressure experimental stations in Korea and Japan to conduct HPHT (high pressure and high temperature) diamond synthesis. Present paper discusses pressure calibration of FB apparatus at high temperature to establish P-T condition of diamond synthesis. We also present some examples of controling P-T condition through careful experimental set-up of the high pressure sample cells. Finally we discuss reproducibility of pressure and temperature condition of the HPHT diamond synthesis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.985-990
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• 2002

The electrical breakdown characteristics of liquid nitrogen(LN$\sub$2/) were studied under simulated quenching conditions for application of HTS apparatus. The experimental results for various quenching condition revealed that the breakdown voltage of LN$\sub$2/ with bubble flow velocity and gap spacing. In the case, breakdown voltage decreases gradually with the bubble velocity. When it is bubble velocity from 0 to 1 $\ell$ /min, breakdown voltage rapidly decreases but decreases from 2 $\ell$/min to 10 $\ell$/min slowly. The breakdown voltage for vertical electrode arrangement is higher than that for horizontal electrode arrangement. Also, it did a electric field and potential distribution interpreting at the liquid nitrogen when the bubble existed. The plots of equipotential lines for three cases are also shown.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.275-277
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• 1993

It is practically required to develop an optical transmission system, for the diagnosis of electric power apparatus, which enables to distinguish the right signals related to the partial discharge taken place inside the apparatus. These partial discharges are transformed into ultra sonic signals by the sensor and then used for the voltage application to pokels cell. Afterwards, the modulated laser beam is transmitted through the optical fiber. Throughout this work, a laser-beam based detecting system is developed and permits us to reproduce the transmitted signals indirectly without electromagnetic interference. For this purpose the characteristics of this system is well analyzed by means of different type of signals from function generator.