• The Korean Journal of Physiology and Pharmacology
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• 제15권3호
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• pp.137-142
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• 2011

Extremely low frequency magnetic fields (ELF-MF) have the ability to produce a variety of behavioral and physiological changes in animals. The stomach, as the most sensitive part of the neuroendocrine organ of the gastrointestinal tract, is crucial for the initiation of a full stress response against all harmful stress. Thus, the purpose of this study was to examine whether ELF-MF stimuli induce changes in the activity of neuroendocrine cells, considering their involvement in endocrine or paracrine effect on surrounding cells. The exposure to ELF-MF (durations of 24 h and 1 or 2 weeks, 60 Hz frequency, 0.1 mT intensity) altered the distribution and occurrence of gastrin, ghrelin and somatostatinpositive endocrine cells in the stomach of rats. The change, however, in the secretion of those hormones into blood from endocrine cells did not appear significantly with ELF-MF exposure. Comparing with sham control, ELF-MF exposure for 1 and 2 week induced an increase in $BaSO_4$ suspension propelling ratio of gastrointestinal tract, indicating that ELF-MF affects gastrointestinal motility. Our study revealed that ELF-MF exposure might influence the activity of endocrine cells, an important element of the intrinsic regulatory system in the digestive tract. The pathophysiological character of these changes and the mechanism responsible for neuroendocrine cell are still unclear and require further studies.

• 원예과학기술지
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• 제17권6호
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• pp.773-776
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• 1999

선인장 및 몇 가지 식물이 컴퓨터 모니터로 부터 발생되는 ELF 및 VLF 전자파의 차단효과에 미치는 영향이 조사되었다. 모니터의 정면에서 전자파가 가장 많이 방출되었으며, 차단효과의 검증을 위해 식물과 다른 대상물들은 모니터의 정면 혹은 측면에 두었다. 측정된 모든 식물에서 모니터 발생의 전자파 중 자계 (magnetic waves) 차단에는 전혀 효과적이지 못한 것으로 나타났다. 한편, 선인장의 크기, 형태, 그리고 배치방법에 따라서는 약간의 전계(electric waves) 차단효과가 있는 것으로 나타났으나, 경미하여 TCO의 규정치(electric field: 10V/m and 1V/m in ELF and VLF, respectively)에는 미치지 못하기 때문에 실용화하기에는 어려운 것으로 판단된다.

• 한국환경보건학회지
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• 제38권1호
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• pp.18-30
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• 2012

Objectives: The purpose of this study was to estimate the exposure level to extremely low frequency-magnetic fields (ELF-MF) among a selected Korean population using 24-hour personal exposure measurement. Methods: Participants were randomly selected for the measurement of MF exposure under the assumption that the subjects are representative of the overall Korean population. Levels of personal exposure to MF were measured according to the subject's daily activities. Results: The 24-hour time-weighted average (TWA) of 250 participants was $1.56{\pm}4.56$ mG (GM, GSD: 0.79, 2.46 mG). Personal exposure levels for females were higher than for males. The highest personal exposure level was shown in the age group between 20-60 years old. Personal exposure levels according to job category were higher for the non-occupational group than for the occupational group. Conclusions: Our results showed MF exposure exceeding 2 mG per day among 11.3% of the Korean population, indicating a somewhat higher percentage compared to the EMF RAPID Program's results for the U.S population.

• The Korean Journal of Physiology and Pharmacology
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• 제19권2호
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• pp.119-124
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• 2015

The aim of the present study was to assess whether exposure to the combination of an extremely low frequency magnetic field (ELF-MF; 60 Hz, 1 mT or 2 mT) with a stress factor, such as ionizing radiation (IR) or $H_2O_2$, results in genomic instability in non-tumorigenic human lung epithelial L132 cells. To this end, the percentages of G2/M-arrested cells and aneuploid cells were examined. Exposure to 0.5 Gy IR or 0.05 mM $H_2O_2$ for 9 h resulted in the highest levels of aneuploidy; however, no cells were observed in the subG1 phase, which indicated the absence of apoptotic cell death. Exposure to an ELF-MF alone (1 mT or 2 mT) did not affect the percentages of G2/M-arrested cells, aneuploid cells, or the populations of cells in the subG1 phase. Moreover, when cells were exposed to a 1 mT or 2 mT ELF-MF in combination with IR (0.5 Gy) or $H_2O_2$ (0.05 mM), the ELF-MF did not further increase the percentages of G2/M-arrested cells or aneuploid cells. These results suggest that ELF-MFs alone do not induce either G2/M arrest or aneuploidy, even when administered in combination with different stressors.

• 한국산업보건학회지
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• 제22권1호
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• pp.42-51
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• 2012

Objectives: To compare the exposure level of extremely low frequency (ELF) magnetic fields among semiconductor workers, shipyard welders and office workers. Methods: To measure the ELF magnetic field concentration, EMDEX LITE (Enertech, USA) were used and monitored for eight hours continuously. Five companies handling the electric and magnetic field (EMF) source were investigated, which the exposure groups were classified into three groups: semiconductor workers, welders, and office workers. Welder group was chosen as a high exposed group and office group as a low exposed group. Results: The arithmetic mean (${\pm}SD$) and geometric mean (GSD) of personal exposure level of semiconductor workers were 0.73 (${\pm}1.33$) ${\mu}T$, 0.43 (2.88) ${\mu}T$, respectively. The ceiling value ranged between 0.18 and 123.2 ${\mu}T$. Welders were exposed high with the arithmetic mean value of 3.46 (${\pm}\;13.46$) ${\mu}T$ and geometric mean value of 0.45 (4.70) ${\mu}T$, respectively, and ceiling value range of 75.5~129.6 ${\mu}T$. The exposure levels of office workers were low compared to other exposed groups; the arithmetic mean 0.05 (${\pm}0.13$) ${\mu}T$, geometric mean 0.03 (2.38) ${\mu}T$ and ceiling value range 0.37~3.35 ${\mu}T$. This study revealed statistically significant differences of the mean ELF magnetic field exposure doses among three groups (p < 0.01). Conclusions: The average ELF magnetic field exposure doses of semiconductor workers were much higher than those of office workers in control group, but were lower than those of welders in high exposure group.

• 한국산업보건학회지
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• 제16권4호
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• pp.334-345
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• 2006

The objectives of this study were to analyze and compare 24 hrs personal exposure levels of MF at microenvironments such as home, school, educational institute, internet pc game room, transportation, and other places according to time activity patterns using various metrics for children attending the primary schools located near and away from the power lines, and to characterize the major microenvironments and impact factors attributed personal exposure level. The study was carried out for 44 children attending a primary school away from the lines(school A) and 125 children attending a school away from 154 kV power lines(school B), all who aged 12 years and were 6 grade, from July 2003 to December 2003. All participants filled in a questionnaire about characteristics, residence, use of electrical appliances and others. Children wore a small satchel in which EMDEX II and Lite (Enertech, Co. Ltd) and a diary of activity list for period of registration in 20 minutes blocks. All statistical calculations were made with the SAS System, Releas 6.12. The summary of results was presented below. First, about the characteristics of subjects, there no differences between two groups. The subject almost spent about 56 % of their time at home and about 20~25 % of their time at school. Fifty percent of children spent 2 hours at private educational institutes. Second, the personal exposure measurements of children in school B was statistically higher than those of children in school A by various metrics such as arithmetic mean, geometric mean, percentile(5, 25, 50, 75, 95), maximum, rate of change metric, constant field metric. The arithmetic and geometric mean magnetic fields during the time the children were at school B were 0.98 and $0.86{\mu}T$ and were about 23 times higher than those of children were at school A. In conclusion, the significant major determinants of personal exposure level is the distance from the power line to microenvironments.

• 한국안전학회지
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• 제36권4호
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• pp.20-28
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• 2021

With an increase in the commercialization of electricity, and the development of advanced and large electric devices and various wireless radio wave services, concerns over the effects of electromagnetic fields on human health have increased. Accordingly, the World Health Organization encouraged the development of international standards by establishing the 'International Electromagnetic Fields Project' in 1996 based on studies on the harmful effects of electromagnetic fields on the human body. Moreover, the National Institute of Environmental Health Sciences (NIEHS) classified electromagnetic fields as possible carcinogens under Group 2B category, even though they have been found to have a weak correlation with those effects on human health. Mid-to-large-sized electric facilities used at industrial sites mostly adopt a commercial frequency of 60 Hz, and workers handling these facilities are exposed to such extremely low frequency (ELF) fields for a long time. A previous study suggested that exposure to ELF electromagnetic fields with frequency ranges from 0 to 300 Hz, even for a short time, at densities higher than 100 μT may have harmful effects on human body as it affects the activation of nerve cells in the central nervous system by inducing an electric field and current and stimulating muscles and the nervous system in the body. Such studies, however, focused on home appliances used by ordinary people, and research on facilities utilizing high-capacity current and operated by workers at industrial sites is lacking. Therefore, in this study, a 3000 kilowatt generator, which is a high-capacity electric facility employed at industrial sites, was investigated, and the size of the magnetic fields generated during its no-load and high-load operations per distance to produce a map was measured to reveal spots deemed hazardous according to domestic and international exposure standards. The findings of this study is expected to alleviate workers' anxiety about the harmful effects of magnetic fields on their body and to minimize the level of exposure during operations.

• 센서학회지
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• 제5권2호
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• pp.29-36
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• 1996

본 논문에서는 전기기기 및 전력설비의 운전 조작중에 발생하는 극저주파 영역(ELF)의 자장을 측정 및 분석 할 수 있는 장치로써 멀티턴 루우프형 센서를 이용한 3차원 자장측정계에 대해 기술한다. 저주파특성의 개선과 왜곡없는 공간자장성분의 측정 등 우수한 성능을 얻기 위해서, 자장측정계를 멀티턴 루우프형 센서와 증폭기, 능동성 적분기로 구성하여 3차원적으로 설계 제작하였다. 교정실험을 통하여 측정계의 고유응답특성을 산출한 결과, 주파수대역은 x, y, z 축 각각 8[Hz]에서 53[kHz] 정도이고, 응답감도는 9.54, 9.21, $10.89[mV/{\mu}T]$이다. 진동성 임펄스전류발생기를 이용한 적용실험으로써 측정계의 신뢰성을 확인하였고, 소형 전등기의 기동시에 발생하는 자장과 측정거리에 따른 정상운전중의 자장특성을 측정 분석한 결과 자장의 세기는 각각 최대 15.8, $8.61[{\mu}T]$이며, 거리가 증가할수록 급격한 감소를 보였다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권6호
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• pp.2961-2966
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• 2012

Extremely low frequency electro magnetic fields (EMFs) have been classified as possibly carcinogenic to humans by the International Agency for Research on Cancer. An increased number of chromosomal alterations in peripheral lymphocytes are correlated with elevated incidence of cancer. The aim of the present study was to assess occupationally induced chromosomal damage in EMF workers exposed to low levels of radiation. We used conventional metaphase chromosome aberration (CA) analysis and the micronucleus (MN) assay as biological indicators of non ionizing radiation exposure. In the present study totally 70 subjects were selected including 50 exposed and 20 controls. Informed written consent was obtained from all participants and the study was performed in accordance with the Declaration of Helsinki and the approval of the local ethical committee. A higher degree of CA and MN was observed in exposed subjects compared to controls, the frequency of CA being significantly enhanced with long years of exposure (P<0.05). Moreover increase in CA and MN with age was noted in both exposed subjects and controls, but was significantly greater in the former. The results of this study demonstrated that a significant induction of cytogenetic damage in peripheral lymphocytes of workers occupationally exposed to EMFs in electric transformer and distribution stations. In conclusion, our findings suggest that EMFs possess genotoxic capability, as measured by CA and MN assays; CA analysis appeared more sensitive than other cytogenetic end-points. It can be concluded that chronic occupational exposure to EMFs may lead to an increased risk of genetic damage among electrical workers.

• 한국멀티미디어학회논문지
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• 제18권3호
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• pp.401-407
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• 2015

In this paper, we propose the method to eliminate EMI (Electro-Magnetic Interference) in ELF (Extremely Low Frequency) band below 2 KHz for extending the gesture-recognition distance of smart TVs to more than 3m using electric potential sensor. First, we measure the electric field generated from the back panel of a TV and propose the effective arrangement of two sets of differential sensors as well as the shielding method using metal fiber. Also, we eliminate the PLN (Power Line Noise) and other noise generated from the TV and sensors as well as surrounding environments using filters. Using the proposed EMI eliminating methods, we evaluate displacement ratio on measured signals according to distance between sensors and a moving hand. Experiment results show that our proposed method can extend the hand-gesture sensing distance using EPS (Electric Potential Sensor) up to more than 3m, which is enough to satisfy applicability of EPS based remote control to Smart TVs.