• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.5
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• pp.482-485
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• 2016

In this work, a transcranial magnetic stimulation(TMS) experiment on animals is performed to stimulate the brain cortex of the mouse using modulated signals. The proposed TMS system is composed of the inverter, transformer, capacitor, variable inductor, and stimulation coil to generate 1.5 mT magnetic field in the brain cortex of the mouse. The stimulation signal is modulated to square wave where the carrier frequency is swept from 85 to 91 kHz to investigate the stimulation effect. The experimental result shows that when the carrier frequency of the stimulation signal is lower than 89 kHz, the reaction of the mouse does not change while the stimulation signal which has the carrier frequency higher than 89 kHz results in decreasing the threshold of the stimulus for the pressure.

• Investigative Magnetic Resonance Imaging
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• v.17 no.3
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• pp.169-180
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• 2013

Purpose : The purpose of this study was to setup a concuurent transcranial magnetic stimulation (TMS)-functional MRI (fMRI) system for understanding causality of the functional brain network. Materials and Methods: We manufactured a TMS coil holder using nonmagnetic polyether ether ketone (PEEK). We simulated magnetic field distributions in the MR scanner according to TMS coil positions and angles. To minimize image distortions caused by TMS application, we controlled fMRI acquisition and TMS sequences to trigger TMS during inter-volume intervals. Results: Simulation showed that the magnetic field below the center of the coil was dramatically decreased with distance. Through the MR phantom study, we confirmed that TMS application around inter-volume acquisition time = 100 miliseconds reduced imaging distortion. Finally, the applicability of the concurrent TMS-fMRI was tested in preliminary studies with a healthy subject conducting a motor task within TMS-fMRI and passive motor movement induced by TMS in fMRI. Conclusion: In this study, we confirmed that the developed system allows use of TMS inside an fMRI system, which would contribute to the research of brain activation changes and causality in brain connectivity.

• Prospectives of Industrial Chemistry
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• v.23 no.2
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• pp.40-50
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• 2020

소프트 로봇의 수요와 관심이 증가함에 따라 생체 모방형 액추에이터 연구가 큰 관심을 받고 있다. 액추에이터란 외부 에너지를 기계적인 동작으로 변환하는 장치이며, 재료 자체가 유연하여 부드러운 움직임을 재현할 수 있는 소프트 액추에이터의 연구가 활발히 진행되고 있다. 고분자 연성 재료 중에 하나인 하이드로겔은 90% 이상이 물로 구성되어 있기 때문에 생체 친화적이면서 동시에 환경 친화적인 재료이며 이를 기반으로 한 액추에이터 연구가 새로이 각광받고 있다. 최근에는 하이드로겔 액추에이터의 성능 향상을 위해 나노재료를 하이드로겔에 첨가하는 연구가 진행되고 있으며, 나노재료가 갖는 고유의 특성을 활용함으로써 하이드로겔 액추에이터의 자극 감응성 향상, 변형 방향의 제어, 높은 변형 효율 그리고 기계적 물성 증가가 보고되고 있다. 이는 헬스케어를 위한 웨어러블 장치, 재활을 목적으로 한 인공 근육 등에 적용이 가능하다. 본 기고문에서는 자극 감응성 고분자와 나노재료를 이용한 하이드로겔 액추에이터 연구에 대해 자극(전기장, 빛, 열, 자기장)의 종류에 따라 분류하여 소개하고, 합성 전략 및 구동 원리에 대해 간략하게 설명하고자 한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.270-276
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• 2013

We have been unwittingly exposed to magnetic field. Biological effects due to electromagnetic field exposure has been studied over the past several decades. There has been epidemiological studies and laboratory studies. In the case of laboratory studies, the effect has been observed through the cell stimulation of an artificial magnetic field. The used frequency and waveform are various in the cell experiment, but the intensity of the magnetic field is usually around 10G. Intensity of Earth's magnetic field is about 300-400mG. Although this intensity is not much higher than artificial magnetic field as 3-4% amplitude, we can't ignore the effect because every living thing on earth has already adapted for long time ago. In this study, we have designed and implemented the 3-axis magnetic field generation system in oder to remove the static magnetic field in the real-time and kept its intensity less than ${\pm}5mG({\pm}0.5uT)$ using 3-axis helmholtz coil.

• Journal of the Korean Magnetics Society
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• v.15 no.6
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• pp.307-310
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• 2005

To get the spatial feature of arterial pulse, we designed spatial pulse diagnostic apparatus (SPDA) using a 2-dimensional magnetoresistive sensor array. The magnetic field distribution fur magnet may was simulated using finite element method. We recognized that the field distribution of parallel magnet mays was more sensitive and uniformed than that of perpendicular one. Also the spatial displacements of magnet array were agreed with the output signal of magnetic tunnel junction (MTJ) sensor array.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.935-942
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• 2019

This paper descries the operation of a heater which was designed to control a motor that generates an eddy current. As the motor drives the rotor of an eddy current heater, magnetic fields are provided within the air gap between an eddy current heater's rotor and stator. Throughout the research, a rotor composed of 8 and 16 pieces of magnets was used to analyze which are the factors that affect the efficiency of this equipment. Test results showed that the magnetic fields are influenced by variable functions including the velocity of a motor and the quantity of magnets composing a rotor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.5
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• pp.431-438
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• 2022

In functional materials, in situ experimental techniques as a function of external stimulus (e.g., electric field, magnetic field, light, etc.) or changes in ambient environments (e.g., temperature, humidity, pressure, etc.) are highly essential for analyzing how the physical properties of target materials are activated/evolved by the given stimulation. In particular, in situ electric-field-dependent X-ray diffraction (XRD) measurements have been extensively utilized for understanding the underlying mechanisms of the emerging electromechanical responses to external electric field in various ferroelectric, piezoelectric, and electrostrictive materials. This tutorial article briefly introduces basic principles/key concepts of in situ electric-field-dependent XRD analysis using a lab-scale XRD machine. We anticipate that the in situ XRD method provides a practical tool to systematically identify/monitor a structural modification of various electromechanical materials driven by applying an external electric field.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.51-59
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• 2008

Incontinence is the urination disorder as the leakage of urine without her own volition and the woman's representative disease which reduce the life quality. The electromagnetic therapy has high possibility of development cause it has no needs of operant exercise, no arousing of shame and impossibility of infection. But, it has improvement points such as uniformity of the treatment protocol, patient dependance and absent of patient monitoring system. With these demands, the system which stimulate the pelvic flaw muscle with electromagnetic and monitoring the patient status during the therapy is proposed, in this study. And individually adapted electromagnetic therapy system for incontinence patient is also suggested. The proposed system consisted of electromagnetic generation device, cooling device, treating chair, patient monitoring device with pulsation and control software. The simulation for high power system and evaluation confirm was performed. With the development of control software, the convenience of using and maintenance are ensured and the patient adapted therapy protocol is applied. The developed patient adapted electromagnetic therapy system with monitoring device is regarded as the patient affinitive treating method by reducing the riskiness, improving the efficiency with patterned protocol and pre/post therapy. These results, in this study, can bring the safe and organized treatment method to incontinence patients and can lead the variable study for electromagnetic therapy in incontinence.

• Research in Community and Public Health Nursing
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• v.19 no.4
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• pp.696-703
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• 2008

Purpose: To Perform a randomized comparative study investigating the effects of Pelvic Floor Muscle Exercise(PME) and Magnetic Stimulation Therapy(MST) and to identified the problems in each of PME & MST Method: Forty-nine patients with mild stress incontinence were randomly assigned to either of two treatment groups (24 patients in the PME group and 25 in the MST group). The PME group had a video exercising program for 40 times every day during 6 weeks. The MST group was treated with BioCon-2000TM, 2times/ week for six weeks. Pre-test and post-test were performed by Prineometer, 1-hour pad test. and Jackson's BFLUTS questionnaire of Jackson. Collected data were analysed using SAS 9.1 by frequency, Kolmogorov-Smirnov Z. Chi Square-test, t-test, Fisher Exact probability test, Paired t-test, and Wilcoxon's rank sum test. Results: In comparison between before and after PME and MST, statistically significant difference was observed in maximal vaginal pressure, duration of vaginal contraction, amount of urine, and symptom of urination. In the comparison of the effectiveness between PME & MST, only the maximal of vaginal pressure (Z=2.58, p= .010) was significantly different. Conclusion: The factor more effective in the MST group than in the PME group was high compliance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3567-3573
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• 2009

This research proposed a dashpot type mount design using MR fluids, and investigated experimentally the influence of the design parameters of the dashpot MR fluid mount, which affect the damping forces of the dashpot MR fluid mount. In order to observe the influence, the dashpot MR fluid mount which have the different effective length and the core structure is manufactured. The variations of the resistance forces according to different effective lengths of the magnetic pole of MR fluid mount, along which magnetic field is defined, was investigated. It was founded that the resistance forces from the MR mount decreased with increased input frequencies, while increased with increased applied electric current intensities. Nevertheless, there is no appreciable change in the resistance forces with respect to the effective length variations of the magnetic pole of MR fluid mount.