• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.341-341
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• 2009

초전도 케이블의 대용량 전력수송능력을 실계통에 적용하기 위해서는 정상상태 뿐 아니라 계통운용상 발생하는 비정상 상태에 대해서도 안정된 성능을 나타내야 한다. 계통운영시 가장 일반적으로 발생하는 비정상 상태의 하나인 계통불평형부하 상태에서의 초전도 케이블의 특성을 실증적으로 확인하기 위해 한전 고창전력시험센터에서 신뢰성시험을 실시하였다. 삼상 송전계통에서 각 상 도체전류는 각 상의 부하량에 의해 결정이 되므로 과도상태라 해도 상당한 시간동안 도체전류가 불평형일 경우 자기적으로 결합된 차폐층전류의 불평형상태가 발생한다. 차폐층전류는 삼상 순환회로의 중성도체가 존재하지 않는 경우 도체전류와의 차이가 발생하게 되어 자기차폐 실패의 원인이 됨으로서 AC손실 증가요인으로서 영향이 커진다. 본 논문에서는 도체전류의 불평형 상태를 실증적으로 모의 발생시켜 연관된 차폐층 순환전류의 형태 및 특성을 검토함으로서 삼상 초전도 케이블의 불평형 부하특성에 대한 연구 진행경과를 요약한다.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.697-704
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• 2021

It is hard to get Filaments which are materials of the 3D printing Fused Deposition Modeling(FDM) method as radiation shielding in Korea. and also related research is insufficient. This study aims to provide basic data for the development of radiation shields using 3D printing by evaluating the physical properties and radiation shielding capabilities of filaments containing metal particles. after selecting five metal filaments containing metal particle reinforcement materials, the radiation shielding rate was calculated according to the Korean Industrial Standard's protective equipment test method to evaluate physical properties such as tensile strength, density, X-ray Diffraction(XRD), and weight measurement using ASTM's evaluation method. In the tensile strength evaluation, PLA + SS was the highest, ABS + W was the lowest, and ABS + W is 3.13 g/cm³ which value was the highest among the composite filaments in the density evaluation. As a result of the XRD, it may be confirmed that the XRD peak pattern of the particles on the surface of the specimen coincides with the pattern of each particle reinforcing material powder metal, and thus it was confirmed that the printed specimen contained powder metal. The shielding effect for each 3D printed composite filament was found to have a high shielding rate in proportion to the effective atomic number and density in the order of ABS + W, ABS + Bi, PLA+SS, PLA + Cu, and PLA + Al. In this study, it was confirmed that the metal particle composite filament containing metal powder as a reinforcing material has radiation shielding ability, and the possibility of using a radiation shielding filament in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.37-43
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• 2019

This study investigated electrical conductivity, electromagnetic shielding effectiveness, and mechanical property to improve electromagnetic shielding performance of high performance fiber reinforced cementitious composites (HPFRCC). Steel fiber, steel slag and carbon black as a conductive material were incorporated into the HPFRCC mixes. In addition, 2% CNT solution which was produced by dispersing multi-wall carbon nanotube (MWCNT) into water was used as a conductive material. In the test results, electrical conductivity of HPFRCC specimens was very low except for the specimen incorporating 1% carbon black. Micro structure of cement matrix was changed as the curing time increased, which negatively affected the conductive network of HPFRCC. In case of HC1 specimen showing a conductive network (0.083 S/cm), the electrical conductivity of the specimen after being dried at $60^{\circ}C$ for 72 hours to exclude the effect of water on electrical conductivity was significantly reduced to 0.0003 S/cm. The most important parameter of electromagnetic shielding effect was found to be a steel fiber while the effect of carbon black and steel slag was very few. The correlation between electrical conductivity and electromagnetic shielding effect does not seem to be clear.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.3
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• pp.42-49
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• 2024

In the electromagnetic wave shielding material market, superior shielding performance in the high-frequency range, along with flexibility and durability, has emerged as critical requirements. The need for high-performance EMI (Electromagnetic Interference) films to address electromagnetic wave interference issues is growing, particularly in various industrial sectors such as smart electronic devices, automotive electronic systems, and communication equipment. In this study, a trimodal silver paste was developed and fabricated into an EMI film, with its performance evaluated. The developed silver paste, utilizing a modified epoxy binder, exhibited properties suitable for screen printing processes. The film demonstrated excellent shielding performance, with an average attenuation of -99 dB in the high-frequency range of the 5G spectrum (26.5 GHz to 40 GHz), and a shielding effectiveness of -90.3 dB at 33.6 GHz. Flexibility and durability tests showed that the film maintained its flexibility even at a curvature radius of 1 mm. In the bending cycle test, the resistance increased by approximately 25.5% from 0.51 Ω to 0.64 Ω after 10,000 cycles in the outer bending scenario, while in the inner bending scenario, the resistance decreased by about 3.6%, indicating reduced resistance to compressive stress.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.355-356
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• 2007

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.777-782
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• 1998

원자로 압력용기의 건전성은 원전의 수명과 직결되며, 압력용기는 운전기간동안 중성자의 조사에 의해 재료의 성질이 저하된다. 중성자 조사량 감소방안을 도출하기 위해 MCNP코드를 이용, 고리 1호기 14주기 원자로심을 3차원으로 모델링하고, 원자로심 핵연료집합체를 제외한 주변구조물에 새로운 추가차폐체를 설치하여 조사량 감소에 효과가 있는 위치를 찾고, 여러 재질의 차폐 성능도 평가하였다. 분석결과, Ta 패드를 이용한 설계안의 경우에 압력용기 용접부위에서 약 32% 정도의 속중성자 조사량 감소가 있음을 확인하였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.82-89
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• 1999

In this article, the performances of acoustic enclosure with double resilient mount system which was designed by ADD to reduce the radiated noise by main noise source of ships, was tested and evaluated. From test results, it was verified that the acoustic performances of acoustic enclosure satisfied the requirements; vibration isolation level at 1st stage mount system of 15 ㏈ and airborne noise reduction level of 20 ㏈ in broad band.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.60-67
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• 2003

The goal of this paper is to improve EMC performance of circuit breaker. Circuit breaker and control cubicle are interconnected by multi control cable. Also many control cables are laid on each apparatus. These control cables are directly connected by electronic components. So control cables are very important to improve EMC performance of circuit breaker. This paper suggests installing a ground conductor in parallel(PGC) to control cables. Also this paper suggests using shielding cables as secondary cables of voltage transformer in circuit breakers, and grounding both ends of shielding. After applying suggested methods, we verified EMC performance of circuit breaker is improved.

• Journal of the Korea Institute of Building Construction
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• v.20 no.6
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• pp.481-488
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• 2020

The arc thermal metal spraying method (ATMSM) has been used in Korea to improve the electromagnetic pulse (EMP) shielding effect of building and infrastructure by three machines of MS, KMS and HMS (Metal Spray, Korea Metal Spray, High-frequency Meta Spray). The adhesion ability of sprayed metal was found to be 58.32, 64.66 and 87.62% for MS, KMS and HMS, respectively. The metal sprayed area per hour of MS, KMS and HMS was calculated and found to be 14.3, 19.25 and 22.16㎡/h, respectively. The HMS showed the highest metal spray area attributed to the diameter of metal wire i.e. 1.6mm which sprayed 80 mm with 18 m/min. There was minimum loss of metal and the highest efficiency by HMS compared to others. Therefore, it is suggested to use HMS for metal spraying by ATMSM to enhance the EMP shielding effect.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.764-765
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• 2015

전자기 시스템에서 발생하는 손실의 대부분은 열에너지로 발생되며 전력기기와 같은 대용량 시스템의 경우 금속도체부의 국부적 온도상승은 그 자체로도 시스템의 성능을 저하시키거나 심각한 경우 사고를 유발시키며 수명을 단축시킨다. 이를 개선하기 위한 방안으로 Hot-spot 부근에 자기실드를 삽입하여 누설자속을 차폐시키는 방법도 고려되고 있다. 본 논문에서는 이러한 열유동 결합된 자기차폐 문제의 최적설계를 실험계획법을 이용하여 수행하였다.