• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1271-1272
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• 2015

송전선로 아래에서의 전기장과 자기장의 계산은 2013년 밀양 송전탑 사건에서 볼 수 있듯이 매우 중요한 문제로 대두되고 있다. 공간을 전파해 나가는 전자파의 특성과는 다르게 5~60Hz의 매우 낮은 주파수(ELF: Extremely Low Frequency)로 송전을 하는 송전선로에서는 발생원으로부터 거리에 따라 반비례하여 그 크기가 작아지는 정전기장 및 정자기장을 발생시킨다. 하지만 수백 kV의 높은 송전전압 때문에 주변에서의 전기장 자기장의 값이 매우 크게 되고 이로 인한 논란이 많기 때문에 정확한 정량적 해석이 불가피한 실정이다. 본 논문에서는 수백 kV로 송전되는 송전선로에서 발생 하는 전기장과 자기장을 해석적으로 계산하고 지면으로 부터 특정한 높이에 따라 전기장 자기장이 어떻게 변화 하는지에 대한 결과를 분석 하였다. 송전 선하에 전기장 및 자기장의 분포는 MATLAB을 통해서 계산 되었다.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.978-979
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• 2006

Recently, Peoples are exposed the ELF(Extremely Low Frequency) magnetic fields in the vicinity of underground transmission lines, and there are the generally accepted opinion that the magnetic fields affect the human body and there are possibility of the disease. Also in relation to this problem, technical solution methods and research are advanced for reducing the magnetic fields. In this paper, to practically understand the magnetic fields underground transmission lines, We analyze the electromagnetic field distribution in the underground transmission lines by means of FEM(Finite Element Methods) and present that improvement of the effective shielding methods by applying cable arrangements and shielding materials, eddy current problem to the underground transmission lines by means of the numerical analysis Tool.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.2
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• pp.76-81
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• 2006

This paper analysed the characteristics of current density induced inside human body by 60 Hz extremely low frequency magnetic fields according to varying conductivities of human model. Human model was composed of several organs and other parts, whose shapes were expressed by spheroids or cylinders. Organs such as the brain, heart, lungs, liver and intestines were taken into account. Applying the boundary element method to the human model, we estimated effects on the induced current distribution due to differences of the organ conductivity and shape. We find organ conductivity influences most and a cross section area and a position of organ also gives effects.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.88-90
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• 2009

Extremely-Low-Frequency(ELF) magnetic fields are generated around power cables and bus bars in power systems. Such the stray fields may cause disturbances to nearby electronic apparatus and affect even human health. In order to seeking out a proper way to reducing the fields, the first thing to do is to accurately predict field distribution around analysis models of interest. Then, optimization techniques should be applied for finding a more improved design than the initial one. To achieve this goal, commercial electromagnetic software, MagNet, is combined with evolution strategy algorithm. For verification of the proposed method, three-phase power line cables and busbar systems have been tested.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.274.1-274.1
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• 2002

There have been some reports showing that cardiovascular response is affected by exposure to extremely low frequency magnetic field (ELF-MF). In this experiment. we intended to observe if ELF-MF affects the basal level of cardiovascular response and effect of drugs acting on sympathetic nervous system. Rats exposed to MF (60 Hz. 20 G) for 1 or 5 days and sham were anesthetized with pentobarbital-Na. Carotid artery and jugular vein were intubated to measure blood pressure (BP) and inject drug respectively. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.274.2-274.2
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• 2002

Some experiments have been reported that magnetic fields can cause the change of numerous neurotransmitters including excitatory and inhibitory transmitters, which are involved in seizures. In this study we aimed to examine the effect of extremely low frequency magnetic field (ELF-MF) on the sensitivity of seizure response to bicuculline, picrotoxin and NMDA in mice. Mouse were exposed to sham or 20 G ELF-MF for 24 hours and then convulsants were administered i.p. at various doses. (omitted)

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.6
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• pp.1-7
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• 2002

The use of an asymmetric Mach-Zehnder interferometric amplitude modulator to measure a relatively low frequency electric field strength is described. The sensitivity of an electric field sensor using a Ti:LiNbO$_3$ optical modulator is strongly affected by the shape of a electrode(probe antenna). To measure the low frequency electric field, a probe antenna of wide effective area is more useful than the usual dipole antenna. As a proof of this, the optical modulator was fabricated with a plate-type probe antenna and the usefulness of this antenna tested for measuring low frequency electric field strength. Measurements were performed in the range 0.1V/cm to 60V/cm at 60Hz through 100KHz. Using a probe antenna of 10mm$\times$10mm, the output voltage of 10㎷ was measured with respect to the electric field strength of 0.1V/cm at 60Hz. By increasing the effective area of the probe antenna, better sensitivity is obtainable over the measured range.

• Journal of Magnetics
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• v.22 no.2
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• pp.326-332
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• 2017

The effects of exposure to an extremely low-frequency magnetic field (25 Hz 20G) on animal cells have been studied. In some reports, stimulation was performed for fixed frequency and variations in magnitude; however, animal-cell experiments have established that both parameters play an important role. The present work undertook the modeling, simulation, and development of a uniform-magnetic-field generation system with variable frequency and stimulation intensity (0-60 Hz, 1-25G) for experimentation with cell cultures in situ. The results showed a coefficient of variation less than 1 % of the magnetic-field dispersion at the working volume, which is consistent with the corresponding simulation results demonstrating a uniform magnetic field. On the other hand, long-term tests during the characterization process indicated that increments of only $0.4^{\circ}C$ in the working volume temperature will not be an interfering factor when experiments are carried out in in situ cell cultures.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.9
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• pp.403-406
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• 2005

Precise measurement of extremely low resistance shunt is important for characterization and calibration of high current instruments. We tested resistance measurement method for extremely high current shunt (up to 140 kA), where resistance is determined by precise measurement of voltage drop at 10 A test current in the frequency range of 40 Hz to 10 kHz. For the extremely low ac voltage to be precisely measured, a verification of the measurement method was also carried, where the inherent noise is systematically evaluated. The measurement uncertainty was estimated to be $1\;\%\;at\;95\;\%$ confidence level (k=2) for about 50 $\mu\Omega$.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.191-206
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• 2004

The present study investigated the hypothesis that a extremely low frequency magnetic field partially suppresses the synthesis of melatonin in a group of 28 primary schoolchildren living nearby and 60 primary schoolchildren aged 12 years living far away from overhead transmission power lines from December 2003 to April 2004 in Seoul, Korea. The mean personal exposure levels of the primary schoolchildren living nearby overhead transmission power line were 0.37 ${\mu}$T, whereas the value for the primary schoolchildren living away from overhead transmission power line 0.05 mT. From simple analyses, the mean melatonin levels in the primary schoolchildren living nearby were lower than away from overhead transmission power line, but not statistically significant differences in the levels of the melatonin (p=0.2421), whereas the statistically significant differences in the levels of the melatonin related to the distance from residence to power line less and more than 100 m by cut-off point (p=0.0139). In multiple linear regression analyses, distance from residence to power line (p=0.0146) and dietary habit about burned meat (p=0.0170) proved to be significant risk factors in the mean nocturnal melatonin levels in the primary schoolchildren. In conclusion, these results demonstrate that urinary levels of nocturnal melatonin are not altered in primary schoolchildren exposed to extremely low frequency magnetic field(ELF-MF) at overhead transmission power line.