• International Journal of Oral Biology
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• v.35 no.4
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• pp.137-144
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• 2010

To evaluate the biohazard properties of an extremely low frequency electromagnetic field (ELF-EMF), we explored the physical properties of the ELF-EMF that generates the electric current induction in the secondary coil from the chamber of a primary solenoid coil. We subsequently explored the biological effects of a strong alternating electromagnetic field (EMF), ranging from 730-960 Gauss, on the mouse testis. Mice were exposed to an alternating EMF field induced by a rectangular electric current at 1, 7, 20, 40, and 80 Hertz, for 1, 3, 5, and 7 hours. The mouse testes were examined for proliferative activity and apoptosis using the in situ terminal deoxynucleotidyl transferase (TdT) method and by immunostaining of proliferating cell nuclear antigen (PCNA), respectively. We found that the electric currentm induction increased in the 6-8 Hertz range, and that exposure to an ELF-EMF induced the apoptosis of mouse spermatocytes. In situ TdT staining was found to be most prominent in 7 Hertz group, and gradually reduced in the 20, 40, and 80 Hertz groups. These data suggest that a strong EMF can induce reproductive cell death within a short time, and the harmful effects of the EMF are maximal at low frequency alternating EMFs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1515-1524
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• 2015

Recently, for the purpose of preventing the corrosion of a vessel, the electrical corrosion protection device that prevents the corrosions of the hull and the propeller is widely used. However, the electrical corrosion protection method artificially emits the current into the seawater around the hull using the power supply in order to make the hull and propeller be in the state of not being corrosion, so that electromagnetic field is generated outside the hull by the current emitted into the seawater. In this paper, the static and alternating constituents of the electromagnetic field generated in underwater outside the hull are analyzed and a countermeasure is investigated to reduce the strength of the electromagnetic field. In conventional shaft grounding system, the shaft potential is maintained above at least 100mV and the alternating current component constitutes more than 10% of the total current. However, in this paper, a control system was designed in order that the alternating current component and the shaft potential which generate electromagnetic field are maintained within 1% and 2mV respectively, and the performance was verified by simulation.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.144-145
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• 2003

A feasibility study on the alternating jet flow under the static electromagnetic field was carried out. When a fluid with electrical conductivity lies in the static electromagnetic field and moves electric current occurs in the fluid. Due to the electromagnetic field and the electric current, lorentz force generates in the fluid, which undergo the 'breaking' effect to the fluid. In order to simulate the complex fluid flow in the magnetic field, electromagnetic and fluid flow analysis need to be solved simultaneously. In the present study, a SOLA (SOLution Algorithm) scheme was used in order to calculate electromagnetic and fluid flow field. Jet flow without an electromagnetic field was compared with analytical solution in order to validate the flow analysis scheme. Effect of jet velocity on the flow pattern down the jet was investigated.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.124-125
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• 2001

The electro-magnetic vector equation(F=$qv{\times}B$ ; F：force, B：magnetic field, q：plus charge, v ：velocity of the charge) explains well about the rotations of electron and positron under the magnetic field[Ref.1], as in Fig.1(a). Because the electro-magnetic wave is also a motion of the alternating charge and magnetic field as in Fig.2, the force vector has all the time inwarding direction and then the wave has a rotating motion. The positron in the proton has constant charge and alternating one at the same time[Ref.2] and then the alternating charge makes the absorbing force with the alternating charge of the rotating wave ($\pi$-ray) around the nucleus[Ref.2]. (omitted)

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.2 s.25
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• pp.11-19
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• 2006

The underwater electromagnetic signatures of a naval ship are mainly generated from three sources which are the permanent and induced magnetic field in the ship's hull and other ferrous components, the cathodic current electromagnetic field established by the Impressed Current Cathodic Protection(ICCP) system or the Sacrificial Anode and the stray electromagnetic fields generated by onboard equipment. These signatures can be minimized by certain design methods or installation of signature reduction equipment. In this paper, we represented the characteristic of the underwater electromagnetic signature and the signature reduction techniques for a naval ship. Also, we measured the electromagnetic field changes emitted from the real ship using the Electric and Magnetic field Measurement System(EMMS). We found that the underwater electromagnetic signature for a naval ship can be used as input or trigger signal in a surveillance system and an influence mine.

• Journal of KSNVE
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• v.9 no.4
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• pp.747-753
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• 1999

This paper presents results of vibration analysis of a generator-stator core for 500 MW fossil power plant. A finite element analysis using a commercial S/W is performed to estimate alternating electromagnetic forces, mainly of 120 Hz in 60 Hz machines, acting on the core, and then to calculate forced response of the core. Results are compared with design requirements.

• Journal of Astronomy and Space Sciences
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• v.40 no.2
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• pp.89-90
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• 2023

• Journal of Astronomy and Space Sciences
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• v.40 no.2
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• pp.91-92
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• 2023

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.350-355
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• 2003

This paper presents results of vibration analysis of a end-winding of large generator for fossil power plant. A finite element analysis using a commercial S/W is performed to calculate alternating electromagnetic forces, mainly of 120㎐ in 60㎐ machines, acting on the end-winding, and then to calculate forced response of the end-winding under electromagnetic forces. Also, this paper presents analytical and experimental modal analysis results of generator end-winding to validate FE model. We calculated forced response of end-winding on 120㎐, double rotating frequency. These results will be used to evaluate structural reliability of end-winding and applied to update model.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2203-2204
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• 2006

When the coil with alternating current approaches to the conductor the eddy current flows in conductor. Eddy current is concentrated on the conductor surface and decrescent because of skin effet.. In this paper investigated eddy current characteristic that is happened in conductor. Analyzed characteristic using electromagnetic field finite element analysis program that is commercialized to analyze value of eddy current and penetration depth. Analyzed creation value of eddy current and penetration depth in conductor that change operation frequency and the material of conductor, coil outside diameter, inside diameter, position, type of conductor from analyzed eddy current characteristic. The results. using distribution of eddy current and penetration depth data is that will help to forecast ECT(Eddy Current Testing), Eddy current application and use field, eddy current loss.