• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.33.4-33.4
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• 2008

• Proceedings of the Korean Magnestics Society Conference
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• 1996.05a
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• pp.24-25
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• 1996

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.29-30
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• 2012

• Proceedings of the Korean Magnestics Society Conference
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• 1993.03a
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• pp.56-57
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• 1993

• Proceedings of the Korean Magnestics Society Conference
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• 1993.03a
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• pp.86-87
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• 1993

• Proceedings of the Korean Magnestics Society Conference
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• 2005.06a
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• pp.112-113
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• 2005

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.456-463
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• 2018

With the development of weapon systems by mounting various sensors, it makes important to analyze the precise functioning of sensor to external environment. In the case of small arms with magnetic sensor, the malfunction of small arms might be caused by strong external magnetic fields. In this study, the effects of magnetic sensor on external magnetic fields were analyzed, and optimal magnetic shield and shield structure were designed through M&S. In addition, the magnetic-shielding effectiveness of magnetic sensor in small arms was verified with commercial shielding materials. As a result, it was demonstrated that the Fe-Cu-Si-Nd-B with the structure of multi-layer metallic shields was shown the magnetic-shielding effectiveness of 83 % for an external permanent magnet and 19 % for an alternating magnetic field of 180 dBpT at 60 Hz, respectively.

• Steel and Composite Structures
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• v.25 no.3
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• pp.361-374
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• 2017

In this study, the influences of triaxial magnetic field on the wave propagation behavior of anisotropic nanoplates are studied. In order to include small scale effects, nonlocal strain gradient theory has been implemented. To study the nanoplate as a continuum model, the three-dimensional elasticity theory is adopted in Cartesian coordinate. In our study, all the elastic constants are considered and assumed to be the functions of (x, y, z), so all kind of anisotropic structures such as hexagonal and trigonal materials can be modeled, too. Moreover, all types of functionally graded structures can be investigated. eigenvalue method is employed and analytical solutions for the wave propagation are obtained. To justify our methodology, our results for the wave propagation of isotropic nanoplates are compared with the results available in the literature and great agreement is achieved. Five different types of anisotropic structures are investigated in present paper and then the influences of wave number, material properties, nonlocal and gradient parameter and uniaxial, biaxial and triaxial magnetic field on the wave propagation analysis of anisotropic nanoplates are presented. From the best knowledge of authors, it is the first time that three-dimensional elasticity theory and nonlocal strain gradient theory are used together with no approximation to derive the governing equations. Moreover, up to now, the effects of triaxial magnetic field have not been studied with considering size effects in nanoplates. According to the lack of any common approximations in the displacement field or in elastic constant, present theory has the potential to be used as a bench mark for future works.

• Journal of Power Electronics
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• v.14 no.2
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• pp.351-361
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• 2014

The discrete torque generation mechanism and inherently nonlinear magnetic characterization of switched reluctance motors lead to unacceptable torque ripples and limit the application of these motors. In this study, a phase current profiling technique and torque sharing function are proposed in consideration of magnetic saturation effects and by minimizing power loss in the commutation area between the adjacent phases. Constant torque trajectories are considered in incoming and outgoing phase current planes based on nonlinear T-i-theta curves obtained from experimental measurements. Optimum points on constant torque trajectories are selected by improving drive efficiency and minimizing copper loss in each rotor position. A novel analytic invertible function is introduced to express phase torque based on rotor position and its corresponding phase current. The optimization problem is solved by the proposed torque function, and optimum torque sharing functions are derived. A modification method is also introduced to enhance the torque ripple-free region based on simple logic rules. Compared with conventional torque sharing functions, the resultant reference current from the proposed method has less peak and effective values and exhibits lower copper loss. Experimental and simulation results from a four-phase 4 KW 8/6 SRM validate the effectiveness of the proposed method.

• Journal of the Korean Magnetic Resonance Society
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• v.22 no.4
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• pp.82-90
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• 2018

The term "hangover" refers to symptoms such as headache, heartburn, nausea, and dizziness caused by acetaldehyde created through alcohol decomposition in the body after alcohol intake. Many scientists have conducted research on diverse drugs, foods, and medicinal herbs aimed at eliminating hangovers. However, research on metabolism to objectively verify or measure their effects on hangover symptoms has been lacking. Accordingly, in this study, deep sea water minerals were administered orally at varying concentrations to rats that consumed alcohol, and changes in the levels of amino acids in their bodies were measured using nuclear magnetic resonance spectroscopy to gauge the minerals' effects on hangover symptoms. Thus far, biochemical research on hangover cures has been confined to basic research measuring changes in the levels of alcohol dehydrogenase and acetaldehyde dehydrogenase as well as in the concentrations of ethanol, acetaldehyde, and acetate using spectroscopes such as enzyme-linked immunosorbent assay kits or gas chromatography-mass spectrometers. In comparison, this study presents pharmacokinetic research that simultaneously tracked biomaterials including amino acids and organic acids, metabolites associated with hangover, to clarify hangover mechanisms more specifically. In addition, this study examined hangover mechanisms without an external supply of tracked materials not overlapping with alcohol metabolism-related materials, such as external amino acids and sugars.