• E2M - 전기 전자와 첨단 소재
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• 제10권1호
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• pp.54-60
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• 1997

The electrical and electromagnetic shielding properties have been investigated in polyaniline free standing films with different degrees of elongation cast from N-methyl 2-pyrrolidone(NMP) solution and camphorsulfonic acid(HCSA) doped polyaniline film. The degree of crystallinity of the crosslinked films increased with increasing the draw ratio. For the case of the oriented films doped with hydrochloric acid, we have the values of conductivities up to 173 S/cm. It is considered that the physical micro-crystalline crosslinking domains act as nucleation sites for the increase of relative crystallinity during stretching. We have obtained the value of conductivity 210 S/cm in the HCSA doped polyaniline film cast from the solvent of m-cresol, which is higher than that of the crosslinking oriented films. The electromagnetic shielding efficiency of HCSA doped polyaniline film obtained 37-41 dB in the frequency range of 10MHz-1GHlz, which is higher than that of the crosslinking oriented films. The higher value of electromagnetic shielding efficiency of HCSA doped polyaniline film suggests strong possibility of electromagnetic shielding material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.624-627
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• 2000

The shielding effectiveness of materials is determined by measuring the ratio of the incident electromagnetic power which passes through the material under test. To measure the shielding effectiveness materials made by conductive polymer, the flanged coaxial transmission-line holder based in ASTM D4935-89, was fabricated. This apparatus has dynamic range between 95dB and 120dB in frequency range of 50Mhz-2Ghz. Furthermore, this system can be utilized to measure the shielding effectiveness of materials produced by conductive polymer and can be adapted for shielding materials design.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1642-1651
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• 2021

In this study, isophtalic neopentyl glycol polyester (NPG-PES) based composites with different loading ratios of pure tungsten metal (W), tungsten (VI) oxide (WO₃), tungsten boron (WB) and tungsten carbide (WC) composites were prepared as alternative shielding materials for ionizing electromagnetic radiation (IEMR) shielding. Structural characterizations of the composites were done. Gamma spectrometric analysis of composites for 80-2000 keV energy range was performed and their usability as IEMR shielding was discussed. As a result, the produced composites showed a shielding performance of 60-100% of the lead (the most widely used IEMR shielding material) depending on the reinforcement material, reinforcement loading rate and experimental conditions. Thus, it was reported that produced composites could be an alternative to lead shieldings that have several disadvantages as toxic properties, difficulty of processing and inelasticity.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.18-19
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• 2020

The ElectroMagnetic Pulse (EMP) destroys social infrastructure at once and causes social chaos. However, currently major infrastructures are constructed of concrete that does not have electromagnetic shielding performance. In this study, using the arc metal spraying method is used to evaluate the shielding performance and construction performance of concrete. The electro-magnetic shielding effect is measured by fabricating a shielding room with reference to MIL-STD-188-125, and the construction performance is evaluated by measuring the adhesion strength of thin metal sprayed film-concrete. As a result of the study, when the metal spraying method is applied, the shielding effect is higher than that of the special electro-magnetic shielding concrete, and it is considered to be more economical than the existing metal plate (3~5 mm).

• 한국건축시공학회지
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• 제21권5호
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• pp.459-468
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• 2021

건축물의 외벽 등에서 전자파를 차단하게 되면 건축물 안의 전자기장의 강도를 효과적으로 감소하게 되어 전자파 장해의 감쇠를 가져오므로 이에 대한 기술 개발에 관심이 크다. 본 연구에서는 반도체 분야에서 발생되는 SiC 부산물과 흑연을 선정하였고 분쇄 등 전처리 후 모르타르에 혼입하여 물성 및 전자파 차폐 성능을 평가하였다. 각 차폐 소재의 경제성을 고려하여 실험체 최외측 10% 부피만 각각의 차폐 소재를 혼입하여 차폐 성능을 평가하였고 차폐 효과 평가식을 활용하여 실험체 전체 부피에 차폐 소재를 혼입한 실험체를 제작할 경우 차폐 성능을 예측하였다. 실험 결과, SiC 알갱이 형태의 차폐 소재 혼입 시차폐 성능은 최대 20dB, 흑연 분말을 차폐 소재로 혼입 시 차폐 성능은 최대 18dB, SiC 분말을 차폐 소재로 혼입 시 차폐 성능은 최대 28dB로 예측 되었고 99.9%의 차폐율을 갖는 것으로 알려진 30dB에 근접한 우수한 차폐 성능을 가지는 것을 확인하였다.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.283-292
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• 2022

Advanced radiation applications have been widely used and extended to many fields. As a result of this fact, choosing an appropriate shielding material based on the radiation application has become vital. In this regard, the integration of elements into polymer composites has been investigated and contributed to the quantity and quality of radiation shielding materials. This study reports photon attenuation parameters and electromagnetic shielding effectiveness of a novel polymer composite prepared with a matrix reinforced with three different proportions (5, 10, and 15 wt%) of niobium content. Addition of Nb dopant improves both photon attenuation and electromagnetic shielding effectiveness for the investigated composites. Therefore, Nb(15%) polymer composite with highest concentration has been found to be the best absorber for ionizing and non-ionizing radiations. Consequently, the performed analyzes provide evidences that the prepared Nb-reinforced polymer composite could be effectively used as photon radiation attenuator and electromagnetic shielding material.

• 한국해양공학회지
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• 제23권3호
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• pp.35-39
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• 2009

The main objective of this study was to investigate fiber reinforced composite materials (FRCM) with electromagnetic shielding characteristics using aluminum (Al) film and copper (Cu) meshes. This study investigated the electromagnetic interference (EMI) shielding effectiveness (SE) of fiber reinforced composites filled with Al film, Cu meshes, and nano carbon black as hybrid conductive fillers to provide the electromagnetic shielding property of the fiber reinforced composites. The coaxial transmission line method of ASTM D 4935-89 was used to measure the EMI shielding effectiveness of composites in the frequency range of 300 MHz to 1.5 GHz. The variations of SE of FRCM with Al film, fine Cu, and general Cu meshes are described. The results indicate that the FRCM having Al film exhibited up to 75 dB of SE at 1.5 GHz.

• Journal of Welding and Joining
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• 제20권1호
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• pp.76-82
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• 2002

In these days, many advanced nations have enforced import restrictions against things emitting electromagnetic wave which has report that it is so harmful. In general, electromagnetic wave is composed of electric wave and magnetic wave. The reflection of electromagnetic wave is mainly reflected by conductive materials and the magnetism loss is generated by magnetic ferrite. The magnetism loss of ferrite is separated by eddy current loss, residual magnetism loss and hysteresis loss. Thermal sprayed coating is intended to manufacture because of simple processes and high efficient electromagnetic wave shielding. The high efficient thermal sprayed coatings were made from the magnetic ferrite materials that characterizes absorption of electromagnetic wave, and the electric conductive materials that characterize emitting of electromagnetic wave. This study was manufactured thermal sprayed coatings to improve absorption-efficiency, and measured the electromagnetic wave shielding efficiency. As the experimental results, high electromagnetic wave shield efficiency was obtained at wave frequency 2GHz to thermal sprayed ferrite coatings manufactured by size distribution range of spray powders, $38~88\mu\textrm{m}$.

• 한국건축시공학회지
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• 제13권1호
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• pp.84-89
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• 2013

This study aims to examine the effectiveness of electromagnetic pulse shielding in cast-in-place protective shelters using corrugated metal-plates, and then reviews their usability for the Republic of Korea Army. The Korea Corps of Engineering has evaluated corrugated metal-plates as a construction material for cast-in-place structures, which have to defend against mechanical impacts as well as electromagnetic pulses. Corrugated metal-plate is known as a superb mechanical protective material, so much so that it has been employed in ammunition magazines and artillery platforms in the armed forces. Moreover, as a metal, such as steel and copper, it is universally recognized as one of the most effective electromagnetic pulse shielding materials. In addition to effectively shielding from electromagnetic pulses and protecting against mechanical impacts, corrugated metal-plates should prove to be an appropriate construction material for the cast-in-place protective shelter in terms of construction availability and economic feasibility. The shielding effectiveness of the suggested structures is examined based on MIL-STD 188-125-1. A few frequency bands need an increase of 15~30dB in shielding effectiveness because of unbidden apertures caused by flaws associated with welding, assembling, and material deformation. However, allowing for the approximately 40dB of shielding provided by soil; the examined structure, which is buried underground, can offset its shortcomings sufficiently.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2011년도 춘계학술대회
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• pp.111-112
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• 2011