• Current Optics and Photonics
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• v.4 no.2
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• pp.134-140
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• 2020

A significant enhancement of the magneto-optical Faraday rotation and extraordinary optical transmission (EOT) in the cascaded double-fishnet (CDF) structure with periodic rectangular apertures is theoretically predicted by using the extended finite difference time domain (FDTD) method. The results demonstrate that the transmittance spectrum of the CDF structure has two EOT resonant peaks in a broad spectrum spanning visible to near-infrared wavebands, one of them coinciding with the enhanced Faraday rotation and large figure of merit (FOM) at the same wavelength. It is most important that the resonant position and intensity of the transmittance, Faraday rotation and FOM can be simply tailored by adjusting the incident wavelength, the thickness of the magnetic layer, and the offset between two metallic rectangular apertures, etc. Furthermore, the intrinsic physical mechanism of the resonance characteristics of the transmittance and Faraday rotation is thoroughly studied by investigating the electromagnetic field distributions at the location of resonance. It is shown that the transmittance resonance is mainly determined by different hybrid modes of surface plasmons (SPs) and plasmonic electromagnetically induced transparency (EIT) behavior, and the enhancement of Faraday rotation is mostly governed by the plasmonic electromagnetically induced absorption (EIA) behavior and the conversion of the transverse magnetic (TM) mode and transverse electric (TE) mode in the magnetic dielectric layer.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.791-794
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• 2008

MRE(Magneto-rheological Elastomer) is a material which shows reversible and various modulus in magnetic field. Comparing to conventional rubber vibration isolator, MREs are able to absorb broader frequency range of vibration. These characteristic phenomena result from the orientation of magnetic particle (i.e., chain-like formation) in rubber matrix. In this study, NR was used as a matrix in order to manufacture MREs. Magnetic reactive powder(MRP), having rapid magnetic reaction, was selected as a magnetic particle to give magnetic field reactive modulus. The mechanical properties of manufactured MREs were measured without the application of magnetic field. The results showed that the tensile property and resilience were decreased while the hardness was increased with the addition of CIP. The analysis of MR effect was carried out by FFT analyzer with various magnetic flux. As the addition of MRP and magnetic flux increased, increment of MR effect was observed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.344-349
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• 2012

This paper presents a new small-sized damper featuring magneto-rheological (MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, The proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.11
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• pp.1121-1127
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• 2012

This paper presents a new small-sized damper featuring magneto-rheological(MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, the proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.

• Structural Engineering and Mechanics
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• v.78 no.5
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• pp.557-572
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• 2021

The current study considers free vibration of the spherical panel with magnetorheological (MR) fluids core and magneto-electro-elastic face sheets. The panel is subjected to electro-magnetic loads and also is located on an orthotropic visco-Pasternak elastic foundation. To describe the displacement components of the structure, the first-order shear deformation theory (FSDT) is used and the motion equations are extracted by employing Hamilton's principle. To solve the motion differential equations, Navier's method is selected as an exact analytical solution for simply supported boundary conditions. Effect of the most important parameters such as magnetic field intensity, loss factor, multi-physical loads, types of an elastic medium, geometrical properties of the panel, and also different material types for the face sheets on the results is considered and discussed in details. The outcomes of the present work may be used to design more efficient smart structures such as sensors and actuators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.538-539
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• 2012

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.946-953
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• 2018

Photo-plethysmography (PPG), which measures changes in the peripheral blood flow of a human body using difference in absorption rate of light, is a measurement method that is studied and used in clinical and various applications due to its simple circuit configuration and measurement convenience. Magneto-plethysmography (MPG), which is newly developed by our team, is a method of measuring changes in the conductivity of biological tissues by using a eddy current induced by a time-varying magnetic field, and is not subject to optical interference. In this study, we investigated the detection characteristics of MPG according to the change of the conductivity of the object and fluid to be measured by simultaneously measuring PPG and MPG. In order to control the speed of fluid known in advance, a blood flow simulator was implemented and used. The fluid used in the experiment was general mineral water and physiological saline (0.9% NaCl) solution. Experimental results show that the amplitude change of the measured PPG was 0.3% in normal water and saline solution, and that of MPG was 77.3%. Therefore, it is considered that the magneto-plethysmography (MPG) has a strong correlation with the conductivity of the fluid.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.21-26
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• 2010

This paper describes patch antenna design method of antenna high gain and broad bandwidth using cylindrical magneto material around feeding line. Strong current induction method applied combination to generate magnetic fields around feeding line for antenna high gain characteristic and principle of PIFA designed application for design of antenna broadband. In case of single CMM, gain increased 3.96 dB compare with the reference antenna gain however bandwidth characteristic not increased compare with the reference antenna. In case of dual CMM, gain improved about 10 dB compare with the reference antenna and -10 below bandwidth is 700 MHz(50 MHz~750 MHz) with this paper designed high gain characteristic.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.5
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• pp.511-517
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• 2016

This paper presents dynamic characteristics of a new actuator using magneto-rheological(MR) fluid between two electrode type coils. The concept of the actuator is to strengthen the force due to the magnetic field produced by the electrode-coil for MR fluid. The amount and direction of current input to the electrode-coils decide the characteristics of contraction-mode and extension-mode. For achieving the required actuating displacement and actuating force, the yield stress of the MR fluid between two electrode-coils is precisely changed by the input current. In this work, the MR fluid is operated in squeeze mode. The experimental results shown in this paper depict that it can be applied in the micro-level displacement and vibration control system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.576-579
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• 2005

MR (Magneto Rheological) fluids are well known as a smart fluid and their application researches to control vibration have been conducted by many researchers. However, their dynamic properties have not been identified clearly yet. Therefore, the MR effect is investigated by using a rotational viscometer and a single degree of freedom system with an MR damper. The results obtained from the experimental study show that stiffness and viscous damping coefficients of the system with an MR damper are changed according to the variation of the applied current.