• 한국전자파학회논문지
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• 제9권5호
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• pp.687-697
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• 1998

최근 국내 전력설비에서 발생하는 전자계에 대한 관심이 증가하고 있지만 이에 대한 정확한 자료 파악은 극히 미미한 실정이다. 본고에서는 송전선로에서 발생하는 전계와 자계의 수준을 알아보기 위하여 전국 1537H의 송전 선로를 대상으로 전계와 자계를 측정하였다. 측정 지점의 전계와 자계 최대치들의 중간값은 각각 0.47 kV /m, 11.6 mG 최고 값은 각각 3.16 kV /m, 125 mG로 나타났으며, 전세계의 전자계 관련 권고치나 기준치에 비해 낮은 값임을 알 수 있었다. 아울러 몇 가지 경우에 대하여 가전제품에서 발생하는 자계와 일일 자계 노출량올 측정 하였고 이를 송전선로의 자계 크기와 비교하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.752-753
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• 2008

The analytical expressions for magnetic field distributions considering slotting effects, cogging torque and back-emf considering skew effects are established. On the basis of magnetic field solutions, electrical parameters such as back-emf constant and winding inductance are obtained. The predicted results are validated extensively by non-linear finite element (FE) analyses. In particular, test results such as back-emf, cogging torque, inductance and resistance measurements are given to confirm the analyses. Finally, generating performances are investigated by applying estimated parameters to equivalent circuit (EC) of the permanent magnet generator (PMG) and validated extensively by FE calculations and measurements.

• 대한임상검사과학회지
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• 제37권3호
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• pp.220-227
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• 2005

Recently, the use of an electrical apparatus has brought up concerns of health risks from exposure to electromagnetic fields. EMF is composed of electric fields and magnetic fields. Heavy exposure to EMF can occur only in the vicinity of high-voltage overhead transmission lines, close to transformers and underground cables, and also close to large electrical machinery. In this thesis I have investigated the hypothesis of the correlation between occupational exposure to ELF-EMF and the risks of leukemia, anemia, cancer. Therefore, the aim of this study is to investigate whether or not ELF-EMF emitted from electric power stations and transformer substations affect some hematological parameters and tumor markers of electric utility workers. The hematological test results and tumor markers under investigation were similar in the two groups but some of parameters such as RBC, AFP, LDH showed significant difference between the two groups from two sample t-test (p<0.05). The exposure group showed increased LDH level compared to the control group by two sample t-tests. In addition, the abnormal LDH level in the exposure group was observed to be clinically significant by ${\chi}^2$-test. However, the levels of RBC, AFP observed were not clinically significant by ${\chi}^2$-test (p>0.05). These results suggested that ELF-EMF does not affect most blood test parameters except LDH of electric utility workers.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.183-183
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• 2015

Indium tin oxide (ITO)는 넓은 밴드갭을 가지는 n-type의 축퇴 반도체로 태양전지, 스마트윈도우, 터치 센서, organic light emitting displays (OLEDs) 등에 널리 적용된다. 최근 touch screen panels (TSPs)의 높은 전기적 특성 및 고해상도 요구에 따라 고품질 ITO 박막개발의 수요도 증가하는 추세이다. 지금까지 ITO 박막의 물성 및 기계적 특성에 관한 많은 연구가 진행되어 왔지만 ITO 초박막 에서의 근본적인 물성 변화에 대한 연구는 미흡한 실정이므로, 이러한 연구는 필수적이라 할 수 있다. ITO 초박막은 광학적 특성은 우수하나, 낮은 결정성으로 인해 전기적 특성이 나쁘다는 단점을 가지며, 이러한 ITO 박막의 결정성은 초기 박막 성장과정에 많은 영향을 받는다. ITO 박막의 초기성장과정은 핵이 생성된 후(nucleation), 각각의 위치에서 성장하게 되고(growth), 합쳐지면서(coalescence) 연속적인 막을 형성 하는데(continuous), 이러한 초기 박막 성장 과정 중에 핵 생성 밀도를 증가시키고 박막이 연속적으로 되는 두께를 감소시킨다면, 더욱 더 고품질의 ITO 초박막을 얻을 수 있을 것이다. 따라서, 본 연구에서는 박막 초기 형성 과정 중 섬들이 합체되는 두께를 최소화시키기 위하여 EMF(electromagnetic field strength) 시스템을 이용하였다. EMF 시스템은 DC 캐소드에 전자석 코일을 장착하여 전자기장을 추가로 부가한 것으로, 이를 이용할 경우 스퍼터 원자가 중성상태로 기판에 도달하는 것이 아니라, 이온화되어 Vp-Vf의 차이로 가속되어 추가적인 에너지를 공급받음으로써 기판표면상에서 확산을 촉진시키므로 박막이 연속적으로 되는 임계 두께를 감소시킬 수 있는 것으로 기대된다. 실험은 실온에서 DC 마그네트론 스퍼터링법을 이용하였으며, 유리기판위에 4, 6, 8, 10, 12, 20 nm의 두께로 ITO 박막을 제작하였다. 스퍼터링 파워는 150 W (3.29 W/cm3), 작업 압력은 0.13 Pa, 기판과 타깃 사이의 거리는 70 mm였다. 각각의 두께에서 EMF 파워 0, 5, 10, 15, 20, 25, 30 W로 인가하여 박막을 제작한 후, EMF 파워에 따른 ITO 박막의 초기 성장 과정중 표면상태를 AFM (atomic force microscope) 이미지를 통하여 관찰하였다. 또한, 두께 약 8 nm에서와 20 nm일 때의 전기적 특성 및 광학적 특성을 관찰하였으며, 두 박막 모두 EMF 파워 15 W를 인가하였을 때 그 특성이 가장 향상되는 것을 확인하였다. 이러한 결과를 통하여 박막은 초기 성장이 중요하므로, 매우 얇은 두께에서 좋은 특성을 가진 박막을 제작하여야 박막의 두께를 증가시켰을 때도 좋은 특성의 막을 얻을 수 있음을 알 수 있었다. 또한, EMF 파워를 증가시킴에 따라 자장강도를 증가시키는 것과 같은 효과 즉, 플라즈마 임피던스가 감소하는 효과를 내어 증착 중 고 에너지 입자 (Ar0, O-)에 의한 박막손상이 감소한 것으로 판단된다. 따라서 적정 EMF 파워 15 W를 인가하였을때 가장 물성이 좋은 ITO 박막을 얻을 수 있었다. 즉, EMF 시스템을 이용하여 저온 공정에서 결함농도가 적은 고품질의 ITO 초박막을 제작할 수 있었다.

• Biomolecules & Therapeutics
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• 제22권6호
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• pp.570-576
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• 2014

Studies have demonstrated that electromagnetic waves, as the one of the most important physical factors, may alter cognitive and non-cognitive behaviors, depending on the frequency and energy. Moreover, non-ionizing radiation of low energy waves e.g. very low frequency waves could alter this phenomenon via alterations in neurotransmitters and neurohormones. In this study, short, medium, and long-term exposure to the extremely low frequency electromagnetic field (ELF-EMF) (1 and 5 Hz radiation) on behavioral, hormonal, and metabolic changes in male Wistar rats (250 g) were studied. In addition, changes in plasma concentrations for two main stress hormones, noradrenaline and adrenocorticotropic hormone (ACTH) were evaluated. ELF-EMF exposure did not alter body weight, and food and water intake. Plasma glucose level was increased and decreased in the groups which exposed to the 5 and 1Hz wave, respectively. Plasma ACTH concentration increased in both using frequencies, whereas noradrenaline concentration showed overall reduction. At last, numbers of rearing, sniffing, locomotor activity was increased in group receiving 5 Hz wave over the time. In conclusions, these data showed that the effects of 1 and 5 Hz on the hormonal, metabolic and stress-like behaviors may be different. Moreover, the influence of waves on stress system is depending on time of exposure.

• 소성∙가공
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• 제23권7호
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• pp.431-438
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• 2014

For electromagnetic forming(EMF) the most important feature is a forming coil which creates the electromagnetic force(Lorentz force), using current density and a magnetic field. Most previous papers have concentrated on the final configuration of the blank or the efficiency of EMF process. Studies focused on the design parameters affected by the forming coil performance have not been conducted. In order to design a suitable forming coil for an object, the current study uses LS-DYNA EM-Module to not only optimize the coil but also to examine the effect of coil performance. By this method a suitable forming coil was made and tested to determine whether or not good formability was achieved in a free bulge test Numerical analysis was also used. The workpiece was Al 1100-O with a thickness of 1.27mm and the coil was made from copper CW004A, which has good electrical conductivity and is suitable for electrical components.

• The Korean Journal of Physiology and Pharmacology
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• 제22권3호
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• pp.277-289
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• 2018

The exponential increase in the use of mobile communication has triggered public concerns about the potential adverse effects of radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phones on the central nervous system (CNS). In this study, we explored the relationship between calcium channels and apoptosis or autophagy in the hippocampus of C57BL/6 mice after RF-EMF exposure with a specific absorption rate (SAR) of 4.0 W/kg for 4 weeks. Firstly, the expression level of voltage-gated calcium channels (VGCCs), a key regulator of the entry of calcium ions into the cell, was confirmed by immunoblots. We investigated and confirmed that pan-calcium channel expression in hippocampal neurons were significantly decreased after exposure to RF-EMF. With the observed accumulation of autolysosomes in hippocampal neurons via TEM, the expressions of autophagy-related genes and proteins (e.g., LC3B-II) had significantly increased. However, down-regulation of the apoptotic pathway may contribute to the decrease in calcium channel expression, and thus lower levels of calcium in hippocampal neurons. These results suggested that exposure of RF-EMF could alter intracellular calcium homeostasis by decreasing calcium channel expression in the hippocampus; presumably by activating the autophagy pathway, while inhibiting apoptotic regulation as an adaptation process for 835 MHz RF-EMF exposure.

• Journal of Yeungnam Medical Science
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• 제21권2호
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• pp.167-176
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• 2004

Background: Electromagnetic fields (EMF) are ubiquitous in modern society including medical field. As the technology of medical instruments and telecommunications has developed rapidly, it has influenced on our lives in many ways. Modern medical practice requires high quality medical equipments, which have a great deal of electromagnetic interference and susceptibility. The purpose of this study were to evaluate electromagnetic condition under usual clinical condition and to suggest a practical guideline in general hospital. Materials and Methods: The actual state of the electromagnetic interference in the medical field was studied under usual clinical conditions including operating rooms, intensive care units, magnetic resonance imaging unit, and hyperthermia unit. Results: There was considerable noise as a result of electromagnetic fields from medical equipments including electrosurgical units and hyperthermia unit, and cellular phones, which could induce serious functional derangements of functioning medical devices. Conclusion: It will be necessary to evaluate the individual electromagnetic situations under various medical conditions and to define a limited zone for cellular phone as well as reposition medical equipments to secure a safer medical practice and to minimize electromagnetic interference.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.97-99
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• 1997

For two decades and more, a lot of research work on the biological effects of EMF (Electromagnetic Field) on human health have been reported. Electric facilities in a typical substation are the main source of magnetic field. This paper presents the measurement and analysis of magnetic field in 345/154KV outdoor substation. The magnetic field depends on the currents which distributed by electric facilities. The result of this paper will be able to be used as basic informations to reduce the level of EMF from the electric utility facilities.

• 전기학회논문지
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• 제59권12호
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• pp.2179-2189
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• 2010

This paper deals with analytical techniques for performance evaluation of small scaled wind power generator with outer permanent magnet rotor. In part (1), using transfer relations theorem, magnetic field distribution characteristics by PM and armature reaction field are derived. Moreover, electrical parameters such as back-EMF, inductance and resistance are calculated from the obtained field characteristic equations. The proposed analytical techniques are validated by nonlinear finite element method using commercial software 'Maxwell' and performance experiments of the manufactured generator. In part (2), generating characteristics analysis such as constant speed characteristics and constant resistive load characteristics, and performance evaluation according to variation of wind speed will be accomplished using the derived electrical parameters.