• 전자통신동향분석
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• 제34권3호
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• pp.86-92
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• 2019

New products and services, such as 5G and wireless power transmission equipment, have recently brought about changes in the field of electromagnetic technology. There is a need for the evaluation and measurement of the health effects of such technology. To address this need, the development of international standards related to human exposure to electromagnetic waves of these new technologies are currently being discussed. This article briefly introduces the International Standard Organization standards for human exposure to electromagnetic waves, and focuses on the major standard trends for SAR measurement techniques that employ vector probes, wireless power transfer, and 5G base station measurement.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.466-469
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• 2008

As the industry develops, they are interested in the fault of electric machines and the effect on human beings by electromagnetic fields and waves which generate through much use of electric machines and appliances. In foreign country, they confirmed the standard about electromagnetic interference and compatibility(EMI/EMC) of electromagnetic fields and waves generating electricity transmission/distribution equipments and electric appliance. In Korea, such criteria are applied too. Before EMI/EMC standard is applied, it is important to prepare the plan to predict and reduce electromagnetic fields and waves which generate in the inner and the outer part of electric machinery. To solve such a problem, they calculated Maxwell's equations by finite element method(FEM) and finite difference method(FDM) in most papers. However, these methods have the disadvantage that mathematical expansions are complex and need much memory allocations for grid and mesh generations. In this paper, we introduce transmission line matrix(TLM) method that media of which trains consists are regarded as transmission lines for electromagnetic field calculation in Korean High Speed Train, calculate the electric and magnetic field, and analyze the results.

• Journal of electromagnetic engineering and science
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• 제4권2호
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• pp.51-55
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• 2004

With the progress of the electronics industry and radio communication technology, certain problems, such as electromagnetic interference(EMI), have arisen due to the increased use of electromagnetic(EM) waves. International organizations such as CISPR, FCC, and ANSI have provided the standards for the EM wave environment and for the countermeasure of the electromagnetic compatibility(EMC). EM wave absorbers are used for constructing an anechoic chamber to test and measure EMI and electromagnetic susceptibility(EMS). In this paper, we have designed an one-body EM(electromagnetic) wave ferrite absorber, based on the equivalent material constants method for both normally and obliquely incident waves, whose absorption abilities are superior to that of the conventional ones. The fabricated absorber has a thickness of 27.68 mm and shows an absorption ability over 20 ㏈ in the frequency from 30 MHz to 6 ㎓.

• 비파괴검사학회지
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• 제36권2호
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• pp.149-154
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• 2016

The use of nonlinear ultrasonics wave has been accepted as a promising tool for monitoring material states related to microstructural changes, as it has improved sensitivity compared to conventional non-destructive testing approaches. In this paper, third harmonic generation of shear horizontal guided waves propagating in an isotropic plate is investigated using the perturbation method and modal analysis approach. An experimental procedure is proposed to detect the third harmonics of shear horizontal guided waves by electromagnetic transducers. The strongly nonlinear response of shear horizontal guided waves is measured. The accumulative growth of relative acoustic nonlinear response with an increase of propagation distance is detected in this investigation. The experimental results agree with the theoretical prediction, and thus providing another indication of the feasibility of using higher harmonic generation of electromagnetic shear horizontal guided waves for material characterization.

• Journal of electromagnetic engineering and science
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• 제11권4호
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• pp.290-297
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• 2011

Recent progresses in the live electrooptic imaging (LEI) technique are reviewed with emphasis on its functionality of real-time visual accesses to traveling electric waves in the GHz range. Together with the principles, configurations, and procedures for the visual observation experiments by an LEI camera system, the following results are described as examples indicating the wide application ranges of the technique; Ku-band waves on arrayed planar antennas, waves on a Gb/s-class digital circuit, W-band waves traveling both in slab-waveguide modes and aerially, backward-traveling wave along composite right/left-handed transmission line, and, waves in monolithic microwave integrated circuit module case.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.244-249
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• 2004

In this paper, shielding effectiveness(SE) of the shielding paint of electromagnetic(EM) waves was investigated with actual experiments. The shielding paint used in this study were made of powder of conductive materials - Ag, Cu, Al, Sn, Ni. Cr, Graphite and Charcoal etc. with a solubility in oil and water. Also, the paper was used as a base sheet. The experiment was carried out by using a shielding evaluator(Shielding box) TR17302 with an ADVANTEST spectrum analyzer, model R3361C. It was found from the experimental results that silver, copper, nickel were good candidates as a shielding material against the EM waves with increasing the SE as the composite was laminated. The characteristics of the SE against the EM waves depended on a mode of preparation of specimen. The effects of density of particles on the SE were studied about the EM shielding paint. The SE strongly depended on the electric resistance by density of painting particles. SE increased as the density of particles was increasing.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2245-2247
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• 1999

Insulation diagnosis techniques of power equipments for the stable power supply and prevention from accidents are of high importance. Diagnosis techniques is able to prevent from large accidents before they happen by finding signs of the accidents. From this point of view, this paper simulated discharge progress and partial discharge using needle-plan electrode system in air, studied the distribution of frequency spectrum of the radiated electromagnetic waves using biconical antenna and spectrum analyzer. From results of this study. the new method was introduced for measurement and analyzation of the radiated electromagnetic waves in accordance with discharge progress in air. Besides, according to the consideration of the mutual relation between frequency spectrum of the radiated electromagnetic waves and discharge progress, it was confirmed that detecting partial discharge and estimating discharge progress were possible.

• 조명전기설비학회논문지
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• 제22권1호
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• pp.157-164
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• 2008

본 논문에서는 모의 GIS 내부에 도전성 파티클을 놓아둠으로써 전하의 축적과 전계의 집중이 용이하도록 하여 부분방전을 모의하였다. 이때 부분방전 발생과 진전에 따른 방사전자파를 스펙트럼 분석기와 EMI.EMC 측정용 안테나($30{\sim}2000[MHz]$)를 사용하여 측정 분석하였다. 모의 GIS 내부에 도전성 파티클 존재에 따른 부분방전의 검출과 방진전전 과정의 판단을 위한 절연진단의 방법으로써 본 논문에서 제안한 측정 주파수의 대역의 분리와 데이터 측정과 분석법을 이용하면 부분방전의 검출과 방전과정의 판단이 가능함을 확인하였다.

• 한국항해학회지
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• 제21권2호
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• pp.69-75
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• 1997

A modern electric system located at a certain distance from the discharge may respond with unexpected sensitivity, when an electrostatic discharge (ESD) phenomenon occurs heteronomously between metallic objects. For analyzing the transient electromagnetic fields caused by ESD, two resistance formulas - Toepler and Rompe-Weizel -are introduced. The experimental result given by Wilson-Ma are used to compare which of these resistance formulas is proper.

• 정보교육학회논문지
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• 제25권3호
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• pp.501-510
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• 2021

본 논문은 초·중등 교원을 대상으로 ICT 전파 연수교육을 실시하고자 액션러닝을 활용한 교재를 개발한 결과와 이를 시범적으로 적용한 결과를 보여 개발된 교재의 현장 적용 가능성을 가늠해보고자 서술되었다. 이를 위해 여러 교과목 수업과 연계하여 활용할 수 있도록 구성하고 다양한 교수 자료를 제공하여 교재를 사용할 교원의 편의를 도모하였으며 10차시의 내용 구조로 교재를 구성하였다. 제안된 교재는 교원연수에서의 시범 적용을 통해 전반적으로 ICT 전파에 관한 이해도가 향상되었으며, 액션러닝 적용 학습을 통해 문제해결력, 협동학습 능력, 민주시민성, 지식정보처리 역량이 제고되어 본 교재가 교원의 ICT 전파 이해도와 역량을 향상하는데 기여하였다고 볼 수 있다.