• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.10
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• pp.653-656
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• 2014

$Cs_3Sb$ photocathode was formed by newly developed process and successive in-situ lighting devices were fabricated in a process chamber. R, G, and B phosphors were applied on the anode plate, respectively. Major parameters such as brightness, power consumption, and efficacy were measured. The wavelength of LED excitation source was 450 nm. Both high power and low power modes were applied in the measurement. Measurement values were clearly differentiated by the voltage application modes. The measured values of each parameter was good enough to be applied for general lighting source. The results showed that $Cs_3Sb$ photocathode formed in atmospheric conditions was functioning as good as the photocathode formed in UHV conditions, and thus it could be applied to advanced lighting devices.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.113-118
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• 2009

Grounding systems set the reference voltage level of electric circuits and suppress the Ground Potential Rise (GPR) by flowing fault currents to the ground safely. There are several parameters which evaluate the performance of grounding systems as ground resistance, touch voltage and step voltage. The touch and step voltages, which is called "risk voltage", are especially important to ensure the safety of human body. This paper dealt with the influence of current sources with the different frequency components on the touch and the step voltages. Three types of current sources as commercial frequency, square wave, and surge with the fast risetime of $50\;ns{\sim}500\;ns$ were used to analyze the risk voltages in a grounding system. The risk voltages showed remarkable difference in the same current amplitude depending on the current sources, and increased linearly with the current amplitude in the same current source. From the experimental results, it was confirmed that the risk voltages can be evaluated by a small current application in large-scale grounding systems and the possible largest risk voltage can be calculated by a surge current with the risetime of 200 ns or a current source with the same frequency component as the surge current.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.293-295
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• 2004

Public utilities adopt the grounding rules ; class I, class II, class III and special class III, and install the grounding electrodes in distribution facilities. To keep the safety of the human and the facilities, Public utilities also manage the value of ground resistance in distribution system biennially. At present the Hook-On meter is normally used to measure the ground resistance although it has ${\pm}5[%]$ measuring error and it can not measure the exact value when the current is over 1[A]. In addition it is very difficult to use the fall-of-potential method in distribution system. In this paper we propose the new measurement method using ground current of distribution system as the current source.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.414-417
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• 1999

According to development of power electric technology from industrial field to electronic home appliances, recent SMPS using semiconductor is spread widely. Electric converting instrument uses a sine wave voltage source, namely an usual power source, and it gets a non-sines power source from power source because current flows through one part in waveform of one cycle. This injects higher harmonic source in source part, absorb pollution source. And this cause quality deterioration, durability shortage of electric power instrument, spreading accident of electric solver system, and so on. It can't supply an electric source of good quality in industry, so become an impedimental element in improving productivity and reliance. This study can be used in prediction of hindrance and diagnosis material and intends to suggest a countermeasure about measurement data.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.229-232
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• 2002

In this paper, we described the laboratory layout of the optical CT in connection with the measurement of large current for the GIS. The aim of this study is the development and application of optical CT based on Faraday effect. It was used He-Ne laser for light source (633nm) and was used PIN-Photodiode for light receiver. The laser source passes through optical fiber in single mode. We used the polarizer to polarize the light source and the beam splitter to divide the output light, and the optical fiber is connected for the measuring the angle polarized in the magnetic field.

• Journal of the Semiconductor & Display Technology
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• v.3 no.1
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• pp.1-7
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• 2004

In this paper, we have developed the DC parameters test system which inspects the properties of DC parameters for semiconductor products. The developed system is interfaced by IBM-PC. It is consisted of CPLD part, ADC(Analog-to-Digital Converter), DAC(Digital-to-Analog Converter), voltage/current source, variable resistor and measurement part. In the proposed system, we have designed the constant voltage source and the constant current source in a part. In the comparison of results, the results of the simulation are very similar to the ones of the implementation.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.18-20
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• 1995

This paper describes a 7.5T magnetic flux density superconducting wiggler that minimize net angular deflection and displacement of an electron rotating along the orbit at storage ring in Pohang Light Source. It consist of dipole superconducting magnet,high uniformity flux distribution due to current source supply,cryostat,vacuum chamber,measurement system. In this paper magnet design procedure, manufacturing, experimental results are contained.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.434-439
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• 2007

Amended Water Quality Environment Preservation Law enacted that the areas where nonpoint pollution is serious can be designated as Nonpoint Source Management Region. According to Section 54 of Water Quality Environment Preservation Law, corresponding watersheds are areas where runoff from nonpoint pollution source may deteriorate river and lake water quality, residents' health and property, and ecosystem. The criteria are as followings; i) where nonpoint source contribution result in or will result in significant ecological destruction, iii) national or local industrial complexes and cities having population greater than one million where nonpoint source managements are necessary, iv) where specific measurement is necessary because of its geological and stratigraphic characteristics. In this research, detailed designation criteria was developed reflecting current nonpoint source management situation and its discharge characteristics. Depending on the result, target regions were also suggested. In additions, it will be desirable that the target regions are prioritized considering institutional execution availability, stakeholder's agreement, and connection with existing nonpoint source pollution management measures.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1054-1056
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• 1999

It is necessary to install the arc generation facility to obtain the important technology for the design of breakers and switches, and the improvement of their performance and reliability. With this facility it is possible to study the characteristics of Arc in air/gas/vacuum insulation environment. The arc generation facility briefly consists of capacitor bank which can charge enormous energy, an air-core reactor, and several measurement equipments. This facility can simulates the arc phenomena in breakers and switches by means of generating high currents. In order to the protect electrode damage during the arcing time in arc extinguishing chamber, we installed auxiliary current source in addition to main capacitor bank, This auxiliary current source produces relatively small arc between electrodes before high current generation by main capacitor bank. Therefore it is possible to observe and measure the arcing phenomenon without damage of electrodes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.883-884
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• 2015

In this paper, a ring oscillator circuit having controllable output characteristics with temperature is introduced. The ring oscillator can be used in the various system to require temperature measurement. The ring oscillator is comprised of a current source and a number of NOT gates and the bias current of the current source is controlled with temperature.