• Analytical Science and Technology
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• v.8 no.4
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• pp.411-418
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• 1995

A method for the direct determination of elemental content in each of aerosol particles by inductively coupled plasma atomic emission (ICP-AES) or mass spectrometry (ICP-MS) is described. This method is based upon the introduction of diluted aerosol into an ICP and the measurement of either the flash emission intensities of an atomic spectral line or ion intensities. A pulse-height analyzer is used for the measurement of the distribution of the elemental content. In order to calibrate the measuring system, monodisperse aerosols are used. The potentials of the method are shown by demonstrating the copper emission signals from the aerosols generated at a small electric switch, a study of the relation between the decreasing rate of particle number density and particle size, and measurements of calcium contents in the individual biological cells.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1807-1809
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• 1997

The salt contamination on the surface of the porcelain insulators used electric power systems causes flash-over accidents. Therefore the quantity of salt contamination should be monitored not to exceed a limit. In this study, we tried laser aided measurement of salt contamination. The Nd:YAG laser beam was focused on the surface of the porcelain insulators which were artificially contaminated, and we detected the D-Line (${\cong}589nm$) of spontaneous emission from the excited sodium atoms with a PMT and an oscilloscope. And we deduced the relation between the detected signals and degree of salt contamination.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1636-1638
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• 1994

Salt deposited on the surface of insulators used in electric power system causes flash-over accidents. Therefore, the quantity of salt on insulators should be monitored not to exceed a critical value. We propose a new remote sensing technique to measure the quantity of salt on insulators of power systems. A pulsed laser beam is focussed on ah insulator to dissociate the salt to sodium atoms. The amount of the salt is measured from the intensity of the spontaneous mission from the sodium atoms. In this paper, a compact salt meter composed of pulsed Nd:YAG laser and omission signal detection system will be introduced. And measurement condition such as the sensitivity, detection range, required laser fluence will be investigated.

• Proceedings of the KIEE Conference
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• 2005.11c
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• pp.90-92
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• 2005

When the jacket damaged conductors in 22.9kV-y overhead distribution lines are contacted with the metal material by strong wind, which, leads to are melting as well as faults accordance. The duration of the arc temperature due to flame effected by weather and flash over conditions. In order to simulated the worst conditions, the ACSR-OC($58mm^2$) used as specimen was artificially cut in no wind. After contacting the two cut conductors again the testing current was applied. thus, the changes in temperature of are flame was analyzed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.1
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• pp.21-29
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• 1993

In this paper, we studied the 50% flashover voltage of lightening impulse which affect the most serious damages on the insulation of the electric power network system. Also its V -t characteristics and corona process phenomena of pure $SF_6, N_2, SF_6-N_2$mixtures under the circumstances of nonuniform field gap are researched. Comparing the characteristics of pure $SF_6$ with that of $SF_6, N_2$mixtures, we discussed that breakdown processes and $SF_6, N_2$ mixture's application to economics.As a results, 50% flashover voltage of $SF_6$ 50% - $N_2$ 50% for impulse voltage is higher then that of 80% of pure SF6, measured data and calculated data by equal area law are almost equal from the points of view of V-t characteristics. Therefore, it has been known that $SF_6$ 50% - $N_2$ 50% mixtures can be used as an economic constitution gas of pure $SF_6$, it is verified that corona processes from Lichtenberg figure.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.396-399
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• 2002

Intense quasi-monochromatic x-ray irradiation from the linear plasma target is described. The plasma x-ray generator employs a high-voltage power supply, a low-impedance coaxial transmission line, a high-voltage condenser with a capacity of about 200 nF, a turbo-molecular pump, a thyristor pulse generator as a trigger device, and a flash x-ray tube. The high-voltage main condenser is charged up to 55 kV by the power supply, and the electric charges in the condenser are discharged to the tube after triggering the cathode electrode. The x-ray tube is of a demountable triode that is connected to the turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to the molybdenum target by the electric field in the tube, the weakly ionized plasma, which consists of metal ions and electrons, forms by the target evaporating. In the present work, the peak tube voltage was almost equal to the initial charging voltage of the main condenser, and the peak current was about 20 kA with a charging voltage of 55 kV. When the charging voltage was increased, the linear plasma x-ray source grew, and the characteristic x-ray intensities of K-series lines increased. The quite sharp lines such as hard x-ray lasers were clearly observed. The quasi-monochromatic radiography was performed by a new film-less computed radiography system.

• Tribology and Lubricants
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• v.38 no.2
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• pp.41-52
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• 2022

Mineral electrical insulating oil, which is widely used in transformers, exhibits excellent cooling performance and transformer efficiency. However, given that it is composed of petroleum-based components, it is weak in terms of biodegradability. This causes environmental problems in case of leakage and a low flash point, which is a factor that would cause great damage in the event of a fire in a substation. In this context, the use of eco-friendly electric insulating oil composed of bio-based vegetable oil and synthetic ester, which has excellent biodegradability and flame retardancy performance, has recently been expanded to the field of electric power, and various research and development (R&D) studies are in progress. According to different research results, vegetable oil and synthetic ester manufacturing technology, thermal stability, oxidation stability, property change, and quality control, which are characteristics of eco-friendly electrical insulating oils, are major factors affecting the maintenance of insulating oil properties. In addition, power companies have established and operated quality control standards according to the use of eco-friendly electrical insulating oil as they expand the exploitatoin of renewable energy in electricity production. In particular, deterioration and oxidation characteristics were jointly identified in R&D as an important influencing factor according to the content of saturated and unsaturated fatty acids present in vegetable oils and synthetic esters in power transformer applications.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.12 s.177
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• pp.70-76
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• 2005

It is known that natural awakening of us in the morning is due to stimulation of the reticular activation system through biological clock in the suprachiasmatic nucleus of hypothalamus by the morning sunlight. If we sleep at dark rooms without windows and so without morning sunlight, thus, it is not easy fur us to get up refreshingly in the morning. In this paper, we propose an automatic sunrise household lighting system that helps us fer getting up cheerfully in the morning even if we sleep in dark rooms without morning sunlight. The proposed lighting system is an embedded system that turns automatically on the electric lamp and makes it brighter and brighter coincidently with the actual sunrise. The proposed system is composed of a PIC microcontroller with flash memory, a real-time clock IC, a D/A converter, an amplifier, a dimmer unit, a light bulb, a display panel and a keyboard. The validity of the proposed intelligent lighting system is demonstrated via a prototype production and experimentation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.554-555
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• 2005

In this paper, we analyzed a metallurgical structure and arc properties of copper wire when the over-current flows on electric wire. From the results, The fusing current was related to the fusing time(current rising rate per second). In case of the shorter the fusing time, the fusing current was high, and the fusing time of ac type was larger than that of dc type. The copper wire was bent by the increase of current and heated, the beads were scattered around wire with a flash. We could observed the dendrite structure in 'molten wire at ac and dc current type. According as the current rising rate per second is short, the dendrite structure is distributed in surface of wire.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.400-403
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• 2002

The fundamental experiments for measuring soft x-ray characteristics from the vacuum capillary are described. These experiments were primarily performed in order to generate line spectra such as x-ray lasers. The generator consists of a high-voltage power supply, a polarity-inversion ignitron pulse generator, a turbo-molecular pump, and a radiation tube with a capillary. A high-voltage condenser of 200 nF in the pulse generator is charged up to 20 kV by the power supply, and the electric charges in the condenser are discharged to the capillary in the tube after closing the ignitron. During the discharge, weakly ionized plasma forms on the inner and outer sides of a capillary. In the present work, the pump evacuates air from the tube with a pressure of about 1 mPa, and a demountable capillary was developed in order to measure x-ray spectra according to changes in the capillary length. In this capillary, the anode (target) and cathode elements can be changed corresponding to the objectives. The capillary diameter is 2.0 mm, and the length is adjusted from 1 to 50 mm. When a capillary with aluminum anode and cathode electrodes was employed, both the cathode voltage and the discharge current almost displayed damped oscillations. The peak values of the voltage and current increased when the charging voltage was increased, and their maximum values were -10.8 kV and 4.7 kA, respectively. The x-ray durations observed by a 1.6 ${\mu}$m aluminum filter were less than 30 ${\mu}$s, and we detected the aluminum characteristic x-ray intensity using a 6.8 ${\mu}$m aluminum filter. In the spectrum measurement, two sets of aluminum and titanium electrodes were employed, and we observed multi-line spectra. The line photon energies seldom varied according to changes in the condenser charging voltage and to changes in the electrode element. In the case where the titanium electrode was employed, the line number decreased with corresponding decreases in the capillary length. Compared with incoherent visible light, these rays from the capillary were diffracted and diffused greatly after passing through two slits.