• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.3
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• pp.155-159
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• 2005

This paper presents the water treatment system with high performance electromagnetic field for a good quality of water. The electromagnetic field water treater consists of a solion, a solion body, and a high voltage converter. The high voltage converter is controlled by PWM current controller. The high voltage converter of 13W is designed for an isolation operation amp, an isolation current detector, and an over current protector. Using the high voltage PWM converter, the system with the proposed electromagnetic field water treater can be controlled easily. Simulation and experimental results show the effectiveness of the system strategy proposed for the scale rejection.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.36-40
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• 2010

In recent society, the electricity is so essential for the human lives. Lots of modern people take many cultural benefits owing to the development of the power systems, the cell phone, the electrical appliances, and etc. However, the problems related to the electromagnetic field generate as the side effects. Examples are the fault in the electric machinery due to the electromagnetic coupling, the fault in the communication devices due to the electromagnetic field around the power line equipments, and the effect upon the human beings due to the electromagnetic field, and etc. In this paper, we induce the vector equation about the magnetic field based on Biot-Savart law. We calculate the magnetic field at the surface of the high speed train with this induced equation and the current in the high speed railroad catenary wire. Finally, we calculate the magnetic field in the high speed train considering the material property like the permeability, the conductivity, and so on.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.369-370
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• 2008

This paper describes the electric field distribution of high voltage polymer bushing with inner field shaper designs. The field control can be achieved by means of the designs of such internal field shaper. But high electric stress occurred between field shaper and central conductor by the closely space. In accordance, the floating and ring shield designs was importance for electric stress grading at critical parts of the bushing. The bushing has a central conductor, and internal ring shield or floating shield, gaps are formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.150-153
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• 2000

NMR researches are required high field and high homogeneous super-conducting magnet. Thus superconducting magnets for NMR applications are designed with minimization of coil winding volume satisfied constraints such as field strength, field homogeneity, etc. In this paper, we are discussed optimal design of high field super-conducting magnet for NMR applications. For a design example, we designed unshielded superconducting magnet for 600MHz NMR spectrometer with 100mm room temperature bore size and obtained 14.1011[T] field strength and 1.33 ppm field homogeneity.

• Journal of Integrative Natural Science
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• v.2 no.4
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• pp.265-269
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• 2009

The photoluminescence was measured in GaAs-AlGaAs double-quantum-well structure at high magnetic field. Although the phototransition characteristics displayed a free-particle transition at low magnetic field, the change of free-particle transition into bound-exciton transition was observed at high magnetic field (above 10 T). A charged exciton formation due to charge-unbalanced electron-hole was identified by using a spin-polarized photoluminescence method. An increase of exciton formation due to the localization of free-particle at magnetic field was observed according to the increase of magnetic field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.4
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• pp.257-263
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• 2013

In this paper, Solar, Wind, fuel cell used in a Power conversion devices and industrial inverter motor to increase the efficiency of energy consumption, which is a core part of high-efficiency, high-voltage Trench Gate Field Stop IGBT was studied. For this purpose Planar type NPT IGBT and Planar type Field Stop IGBT have designed a basic structure designed to Trench Gate Field Stop IGBT based on the completed structure by analyzing the energy consumption of electrical characteristics, efficiency is a key part, high-efficiency and high-voltage inverter for industry regarding the optimization design for Trench Gate Field Stop IGBT.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.4-5
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• 2018

Recently, high-strength concrete used for shortening the construction time of high-rise building construction, Concrete pumping technology is emerging as the core technology of high-rise buildings. In this paper, we have started to study the use of electromagnetic field as a method to increase the efficiency of the lubricating layer between the inside of the pipe and concrete, which has been established as the most important factor determining the pumping performance. The pumping performance improvement effect of concrete strength was verified and basic research was carried out to utilize it as a method to increase the efficiency of pumping in field application. In the related work, the effect of the electromagnetic field was verified by conducting a mock-up performance evaluation (horizontal 300 m) of the pumping force by the concrete strength.

• Journal of the Korean Society of School Health
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• v.33 no.3
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• pp.194-202
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• 2020

Purpose: The purpose of the study was to develop educational materials on field practice safety based on existing field practice data and accident cases regarding vocational high schools and apply them to identify their impact. Methods: The existing data, accumulated since 2010, on field practices of vocational high schools were analyzed, and educational materials regarding field practices were developed by six experts. 195 students in three vocational high schools were surveyed before and after being taught with the materials. The survey asked about their knowledge of industrial safety and health and attitudes toward industrial safety and health. Results: As a result of the study, harmful environments for field practices of vocational high schools were physical, chemical, ergonomic, and emotional labor, and the consequences were accidents, death by overwork, musculoskeletal diseases, etc. The materials covered students' rights and how to respond to workplace accidents in the 1st round, how to organize a workshop in the 2nd round, workplace safety and health signs in the 3rd round, prevention of musculoskeletal diseases in the 4th round, management of physical risk factors in 5th round, management of hazardous chemicals in 6th round, wearing and managing protective equipment in 7th round, first aid depending on the situation in the 8th round, CPR and defibrillator in the 9th round, sexual harassment in the 10th round, and prevention of sexual violence in the 11th round. After completing the education, their knowledge of industrial safety and health increased significantly from 6.52 points to 7.01 points. Conclusion: The results of this study suggest: first, to statistically organize the data on accidents that have occurred during field practices of vocational high schools; second, to develop a systematic curriculum for high school 1st to 3rd graders on accidents that may happen during field practices of vocational high schools.

• Journal of The Korean Association For Science Education
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• v.17 no.1
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• pp.85-92
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• 1997

The field is a good learning environment that offers many opportunities. Status of conducting field trip in the middle and high school was investigated As a result, there was few teachers who disagree that a course in science should include learning in the field. Yet, on practical side, teachers who used to conduct the field trip over once a year in science class appeared to be about 23% only. Most of schools conducting field trips hadn't well-planned program for instructional activities. Many of teachers appealed that they should not get release time for conducting an extended field experiences, and that they could not obtained good information in relation to the contents, the methods and strategies of field activities. It says that a good field trip needs administrative and financial surport, many informations, and the teacher's exertion.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.9
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• pp.446-451
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• 2006

The output voltage value of AC high voltage source has been usually measured by employing the high voltage divider of inductive or capacitive type. In the study, we have developed a new method for measuring the output voltage up to 60kV using parallel plates electrode and electric field sensor, which are constructed by home-made. Unlikely the conventional method using a high voltage divider, this developed method makes it possible to extend the range of output voltage from known low voltage measurement to high voltage measurement. From the linearity measured between electric field and applied voltage in the output voltage range of 1kV-30kV, the output voltage value up to 60kV can be obtained by the electric field measurement using the electric field sensor. The output voltage value obtained using the method is consistent with that obtained using high voltage divider within corresponding uncertainties.