• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.87-90
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• 2007

The effects of static magnetic field on the human biological system are becoming increasingly more important with the adaption of static magnet in the medical community. It is the goal of this paper to review the effects of static magnetic fields on oxygen saturation level in blood. The results of this paper show that the oxygen saturation level increased in the blood in index finger when the static magnetic dipole was fitted on index finger.

• Journal of the Korean Magnetics Society
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• v.24 no.2
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• pp.66-69
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• 2014

The spreading tube of X-ray cathode tube displayed with an electromagnetic finite element method was designed. To analyze a feature design and the concrete coordinate performance of soft X-ray tube modeling, the orbit of electron beam was simulated by OPERA-3D SW program. The fixed conditions were the applied voltage, the temperature, the work function of thermal electron between cathode and anode of tungsten. Through the analysis of distribution of electron beam and the variation of dividing region, the design of soft X-ray spreading tube equipped with two cross filaments was optimized.

• Journal of Platform Technology
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• v.12 no.1
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• pp.119-127
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• 2024

This paper utilized electromagnetic field energy as an external stimulus to enhance the germination rate of acacia(Robinia pseudoacacia) seeds. Electromagnetic field energy comprises three types: static magnetic field(SMF) energy, static electric field(SEF) energy, and microwave(MW) energy. When SMF energy was applied to seeds through a dry method for 90 minutes, the germination rate increased by more than 10% compared to the control group. Similarly, SEF energy applied through a dry method for 90 minutes resulted in an improvement of over 20% in the germination rate. Furthermore, when MW energy at 2.45 GHz was applied to the seeds through a wet method for 3 minutes, the germination rate increased by over 25%. Experimental results showed that seeds treated with MW energy exhibited the highest germination rate and the greatest sprout growth. Consequently, this paper confirms that treating seeds with MW energy through a wet method yields the most superior germination rate and seedling growth.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.708-710
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• 2003

This paper presents design sensitivity analysis for the electromagnetic force and torque obtained from Coulomb's virtual work method using the adjoint variable method. And virtual displacement field is calculated from a static structural analysis. Derived equations are verified by comparison with finite different method. And topology optimization for a c-core is given as a verification example.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1297-1299
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• 2005

This paper deals with the static analysis of slotless BLDC motor. The transfer relations methodology is employed for predicting the electromagnetic characteristics, with reference to the magnetic field distribution.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.4
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• pp.225-230
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• 2004

An electromagnetic actuator has been designed and fabricated for Probe-based data storage applications. The actuator consists of permanent magnets(SmCo) housing and a media Platform which is connected to the Si frame by four couples of Si leaf springs. In order to generate electromagnetic force, Cu coils were electroplated under the media platform. The magnetic field distribution was calculated with 3D Finite Element Method of Maxwell 3D program. The field strength felt by Cu coils was estimated to be about 0.33T when the distance between the media platform and permanent magnets is $200\mu\textrm{m}$. The static and dynamic motions of the actuator were analyzed by FEM method with ANSYS 5.3. The measured displacements of the actuator were about $\pm$$92\mu\textrm{m}$ for input current of $\pm$40㎃ and the resonance frequency was 100Hz. The proposed electromagnetic actuator can be utilized for media driver of probe-based data storage system.

• Geophysics and Geophysical Exploration
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• v.27 no.3
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• pp.181-195
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• 2024

This tutorial explains that the static effect in the magnetotelluric (MT) survey is a physical phenomenon caused by charges accumulated on the boundaries of subsurface inhomogeneities. To facilitate understanding of the physical phenomenon, differences between static induction and charge accumulation on the boundary are explained and analyzed with help of schematic illustrations. Subsequently, from the electromagnetic (EM) integral equation formulation, it is clearly shown that the secondary electric field due to charges accumulated on the interface in the presence of the primary field appears as the static effect. Therefore, except in the cases of the layered earth or a two-dimensional earth with transverse magnetic (TM) mode excitation, the static effect always exists in MT responses and further, it is not 'static' but rather frequency dependent. Despite the fact that the static effect is a secondary electric field due to inhomogeneity, inevitable under-sampling in the frequency and spatial domains prevent the effect from being handled properly in numerical inversion. Therefore, considering the practical aspects of the MT survey, which cannot be a continuous measurement covering the entire survey area over a wide frequency band, a three-dimensional (3-D) inversion incorporating the static shift as a constraint with the Gaussian distribution is introduced. To enhance understanding of the integral equation EM modeling, the formulation of the 3-D integral equation and mathematical analyses of the Green tensor and scattering current are described in detail in the Appendix.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.2
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• pp.110-119
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• 2013

As the technologies such as middle-range resonant WPT (wireless power transfer) advance that utilizes medium and low-frequency magnetic field, the importance of safety of such magnetic field is growing. The research on the effect of electromagnetic field on the human body has been mainly done on the GHz range of mobile phones, or 50~60Hz range of electric power systems. However, there has been relatively few works on the 100kHz~10MHz range used in the resonant wireless power transfer. Since there is a difference in the limiting value of magnetic field between widely used ICNIRP EMF guideline and IEEE C95.1 standard, there can be possible confusion when establishing EMF (Electromagnetic Field) standard on the wireless power transfer device in the future. In this paper, the induced current in the human body, which is the basic restriction of the EMF guideline, is calculated using Quasi-static FDTD method when 3D high-resolution human model is exposed to the 100kHz~10MHz magnetic field. Using this result, the feasibility of the magnetic field reference level in the ICNIRP guideline is analyzed.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2364-2375
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• 2018

Two-phase simultaneous excitation mode of the switched reluctance motor (SRM) has been shown to effectively improve the average torque output compared with traditional single-phase excitation mode. But the torque ripple of the two-phase excitation SRM with traditional winding distribution increases because of the inconsistent electromagnetic field. To reduce the torque ripple, a two-phase excitation 8/6 SRM with novel winding distribution is proposed in this paper. The static torques generated by various magnetic circuits are analyzed and obtained to verify the torque increase. Then the electromagnetic characteristics of the proposed SRM are investigated by the numerical calculation method in detail, including flux linkage, inductance, and torque. Finally, an experiment for measuring the SRM static electromagnetic characteristics and dynamic performance is designed and performed based on the novel mode, and the comparing results show that the proposed two-phase SRM is effective.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.113-113
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• 2003

A number of studies have demonstrated recently nonthermal interactions of extremely low frequency electromagnetic fields with cellular systems, such as the cells of the immune system. Particular concern came from epidemiological findings, which correlated environmental exposure of human body to weak electromagnetic fields with an elevated risk for developing certain type of leukemias and cancers. Several home/environmental sources generating extremely low frequency electromagnetic fields, such as 50 - 60 Hz high-voltage transmission lines, video display terminals, electric blankets, clinical nuclear magnetic resonance imaging procedures, etc., may interact with the human body. In this study we examined the effects of static magnetic fields (SMF) on the phagocytosis of the murine peritoneal macrophages (C57BL/6). The cells were exposed in vitro for 24 h at 37$^{\circ}C$ to 400 G SMF. The phagocytic activity of peritoneal macrophages was determined with a luminometer. Exposure to the SMF decreased phagocytic activity of murine peritoneal macrophages. In order to provide a more exact mechanism of the phenomenon, we analyzed peritoneal macrophages for alteration in their proteomes. The expression levels of these 5 proteins were increased in the SMF. In total 5 proteins which were differentially expressed in the SMF compared with control group were identified. The expression levels of these 5 proteins were increased in the SMF.