• 전기의세계
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• v.25 no.5
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• pp.79-87
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• 1976

This paper is to investigate the A.C generation of MHD engine, converting directly the kinetic energy of conductive gas in high temperature to electric power by the effect of magnetic field. It is known that there are at least two kinds of method in A.C MHD power generation; one, by sending stationary plasma flow in an alternating or rotating magnetic field and the other, by transmission of pulse type plasma flow in uniform and constant magnetic field, former method is adopted here. In order to raise the total efficiency of close cycle in combination with nuclear power and MHD genertaion, an argon plasma jet is utilized as heat source, which is not mixed with the seed material, and the design data are obtained for A.C MHD generation in small capacity, but induced voltage and power output have the maximum values, 15 voltages and 7.5W respectively due to plasma flow with low conductivity and weak magnetic field.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1194-1203
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• 2000

A magnetic field exposure system that generates 60 Hz magnetic fields from 1 mG to 5 G was designed and constructed for small-sized animal study. In order to investigate as many animals as possible at one series of test, uniform magnetic fields are required at wide living area of the animals. In this article, a cubic shaped field exposure system with three animal living floors was designed, which offers about 50 seating capacity. For calculation of magnetic fields inside the cage, a three-dimensional calculation program was developed. Using this, optimum electric current ratio of inner coil to outer coil and position of each coil were determined. Meanwhile, inductance of the exposure system was calculated for the design of power supply. The field measurement results of the manufactured exposure system showed that the difference between maximum and minimum magnetic field at the testing floors was less than 3%, which strongly demonstrated the field exposure system was good for small sized animal study.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.855-859
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• 2004

The Japanese National Project "Carbon Nanotube FED" is developing a high image-quality and low power-consumption field emission display (FED) by applying carbon nanotube (CNT) to the electron source. A uniform electron source with a flat-film CNTs and fine structure triodes Fir suppressing the deviation of emission is required. For realizing an FED panel, it is also necessary to develop the glass-bulb technologies for vacuum sealing, and display technologies for driving the panel by circuit electronic and for evaluating the picture quality by measuring. By achieving these technologies, an FED compatible with conventional Cathode Ray Tubes (CRTs) will be realized.

• 전기의세계
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• v.29 no.8
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• pp.532-537
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• 1980

Effect of Argon and Sulfur hexafloride in the transformer oil are experimented under non-uniform A.C. electric field. The result has shown that the corona frequency and corona charge quantity in liquid dielectrics were varied with gas condition in the oil and affected by the additives. SF$_{6}$ that has the effects of pressure and electrical negative characteristic is the most effective. The corona is considered to be the breakdown of bubble produced by gas contained in the oil or by dissociated ion of the oil molecules.s.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.347-349
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• 2016

본 논문에서는 dopant density에 의존적인 pn junction의 breakdown 특성을 향상시키기 위하여, doping density와 doping profile에 대하여 분석했다. Doping density와 doping profile은 역방향 junction breakdown voltage를 결정하는 중요한 요소인 공핍영역의 두께와 공핍영역 내에 인가되는 electric field를 결정한다. Uniform doping profile과 Gaussian doping profile을 비교했고, 고전압 환경에서 사용할 수 있는 소자를 제작하는데 더욱 적절한 doping profile과 doping 농도에 대해 기술했다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.587-588
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• 2011

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.1
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• pp.47-54
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• 2004

In this study, the electrorheological (ER) fluid was used as finishing agent. Since the apparent viscosity can be controlled by an electric field, the ER fluid can be one of efficient materials in finishing processes. To finish small 3-dimensional structures such as the aspherical surface in optical elements, the possible arrangement of a tool, part and auxiliary electrode was described. We examined the influence of the addition of a few abrasive particles on the performance of the ER fluid by measuring yield stress and observed the behavior of abrasive particles in the ER fluid by a CCD camera, which had been also theoretically predicted from the electromechanical principles of particles. On the basis of the above results, the steady flow analysis around the rotating micro tool was performed considering the non-uniform electric field. Finally, borosilicate glass was finished using the mixture of the ER fluid and abrasive particles and material removal with field strength and surface roughness were investigated.

• Progress in Superconductivity and Cryogenics
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• v.14 no.3
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• pp.38-42
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• 2012

Fixtures such as bushings in terminations of high temperature superconducting(HTS) power cable systems are subjected to high voltages, which have to transition from ambient to cryogenic temperatures. As such it is imperative to ensure the integrity of the dielectrics under all operating conditions, including thermal aspects brought about by the passage of current. Gaseous helium(GHe) at high pressure is regarded as a potential coolant for superconducting cables. The dielectric aspects of cryogenic helium gas are both complex and demanding. In this experimental study we looked at the interface between a smooth epoxy surface and high pressure helium gas in a homogeneous electric field. The alternating current(AC) flashover voltages of epoxy samples are presented. The results have been analyzed by using Weibull statistics. In addition to the behavior of the epoxy in gaseous helium as a function of pressure and temperature we also present data of the characteristics of the epoxy in mineral oil and in liquid nitrogen($LN_2$). The breakdown characteristics of a uniform field gap in gaseous helium as a function of pressure and temperature under AC, direct current(DC) and lightning impulse voltages are also given. Electric field calculations have been made for one of the experimental geometries in an attempt to explain some of the anomalies in the experimental results.

• Journal of IKEEE
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• v.24 no.4
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• pp.1167-1171
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• 2020

In this work, we proposed a graded gate-doping structure to alleviate an electric field in p-GaN gate layer in order to improve the reliability of normally-off GaN power devices. In a TCAD simulation by Silvaco Atlas, a distribution of the graded p-type doping concentration was optimized to have a threshold voltage and an output current characteristics as same as the reference device with a uniform p-type gate doping. The reduction of an maximum electric field in p-GaN gate layer was observed and it suggests that the gate reliability of p-GaN gate HFETs can be improved.

• KIEAE Journal
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• v.5 no.1
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• pp.43-49
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• 2005

People grow up and build up most of their character through living in dwelling space and have relax and refresh at home. Creating healthy dwelling space is being considered very important in architectural planning and design for providing comfortable living environment and improving quality of life. One of the properties of the earth is that the earth has a magnetic field associated with it- the Geomagnetic field. The geomagnetic field is produced by a combination of crustal rocks, external electric current systems that surround the earth that surround the earth and currents induced in the outer layers of the earth by magnetic field variations. Human beings have evolved with the background of magnetic field, they are accustomed to living in its presence. Geopathic stress occurs at geopathic zones where the geomagnetic field is disturbed. Geopathic zones exhibit magnetic charges. Geopathic zones are characterized by variations in geomagnetism, for the geomagnetic field is not uniform but exhibits many highly localized distortions, some random, some fairly regular. These occur in geological faults, caves and underground water channel. Many research papers and experiments of the western countries indicates that the geomagnetic field affects the people and living organism in dwellings. Therefore, it is necessary to investigate the geomagnetic field and people's response in living space. In this study the Health Hazard of geomagneic field in dwelling are studied through literature survey of related science field.