• Journal of the Microelectronics and Packaging Society
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• v.2 no.2
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• pp.49-56
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• 1995

ATM 교환기에 사용되는 하이브리드 IC에 대해 냉각성능과 전자파 차폐성능을 실 험과 수치해석에 의해 분석하였다. 하이브리드 IC 상부에 전자파 차폐를 위해 부착하는 덮 게의 형상에 따라 냉각공기 유속 0.5~0.4m/sec 조건에서 냉각실험을 하였고 냉각 해석 코 드인 Flotherm으로 컴퓨터 시뮬레이션하여 비교하였다. 그리고 각 덮게의 형상에 따라 30MHz ~1GHz 대혁에 걸쳐 전자파 차폐 실험을 하엿다. 실험결과 냉각 특성의 실험과 수 치해석 결과 잘 일치하였으며 공기 유속을 1.0m/sec 이상으로 유지시키면 덮개 형상에 무관 하게 열적으로 안저하였다. 30~700MHz 영역에서는 덮게로 인한 전자파 차폐효과가 뚜렷하 였으나 700MHz 이후의 대역에서는 접지와 접속되는 리이드의 임피던스 증가로 인하여 차 폐효과가 감소하였다.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.129-134
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• 2019

PVC was chosen as a plastic product that can cope with lead, a radiation shielding material that is widely used in medical institutions. In addition to radiation shielding clothing, we want to evaluate whether it can be used as a medical device component and industrial shielding material in low dose areas. Commercial PVC has a density of 3.68 g/㎠ and can be positively expected sufficient shielding effect in certain radiation areas such as material flexibility and economy efficiency, and can be transformed into various forms and used as a lightweight shielding wall. The shielding performance was tested by adjusting the thickness of 5 sheets of 3mm PVC in the range of medical radiation used for clinical examination in medical institutions. Shielding performance against effective energy was evaluated based on tube radiation voltage of medical radiation. The thicker the PVC, the lower the tube voltage and the lower the effective energy, the greater the shielding effect. The shielding effect was 70% at 12mm thickness and 80kVp tube voltage. Therefore, the shielding effect of PVC material has a high dependence of thickness. In the future, continuous research is needed to make thin and light eco-friendly products while improving shielding performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.234-243
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• 2023

The electromagnetic pulse(EMP) is a general term for high-output electromagnetic waves, and is classified into EMP generated from nuclear weapons, non-nuclear EMP, and EMP generated by natural phenomena. Electromagnetic pulses are means that can cause fatal damage to all electronic devices with electromagnetic elements, such as communication devices, mobile phones, computers, TVs, and means of transportation. In this study, the electromagnetic pulse(EMP) shielding effectiveness evaluation of paints according to the type and amount of carbon material was conducted to develop EMP shielding inorganic paint using carbon materials. In order to analyze the improvement of compatibility and dispersibility between materials, experiments were conducted two times with about 27 types of mixture proportions, and the electromagnetic pulse shielding effectiveness was evaluated by the electrical resistance measurement method. As a result of applying the EMP shielding paint developed through this study to shielding concrete, it was confirmed that the shielding performance was improved from about 25 dB to a maximum of 40 dB.

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.170-171
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• 2009

• Polymer(Korea)
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• v.25 no.3
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• pp.367-374
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• 2001

The electromagnetic interference (EMI) shielding effectiveness (SE) of poly(vinylidene fluoride) (PVDF) composites was investigated using carbon nanofiber fillers prepared by catalytic chemical vapor deposition of various carbon-containing gases over Ni and Ni-Cu catalysts. The electrical conductivity of carbon nanofiber which was regarded as the key property of filler for the application of EMI shielding ranged from 4.2 to 22.4 S/cm at a pressure of 10000 psi. The electrical conductivity of carbon nanofiber/PVDF composites ranged from 0.22 to 2.46 S/cm and the EMI SE of those was in the range of 2∼13 dB. The electrical conductivity of carbon nanofibers increased with the increase in heat treatment temperature and time, while the electrical conductivity of the composites increased rapidly at the initial heat treatment and then approached a certain value with the further increase of heat treatment. The SE of the composites showed a maximum at the medium heat treatment and was proportional to the electrical conductivity of the composites. It was concluded that the specific surface area of carbon nanofibers decreased with the continual heat treatment and the specific surface area of filler was an important factor for the SE of the composites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.321-328
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• 2019

A military shelter for communication and information is necessary to optimize the integrated combat ability of weapon systems in the network centric warfare. Therefore, the military shelter is required for EMI shielding performance. This study examines the stable measurement points for EMI shielding effectiveness of a military shelter for communication and information. The measurement points were found by analyzing the EMI shielding effectiveness measurement data with data mining technique and process capability analysis. First, a support vector machine was used to separate the measurement point that has stable EMI shielding effectiveness according to set condition. Second, this process was conducted with process capability analysis. Finally, the results of data mining technique were compared with those of process capability analysis. As a result, 24 measurement points with stable EMI shielding effectiveness were found.

• Composites Research
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• v.35 no.4
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• pp.223-231
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• 2022

With the rapid growth of the future mobility market, a large number of electronic parts are being used in automobile, and the importance of electromagnetic interference (EMI) shielding in the automobile market is growing to minimize malfunctioning among the parts. Accordingly, conductive polymer composites (CPCs) are getting a lot of attention as EMI shielding materials for the automotive, but there are still challenges in CPCs like high content of conductive filler to achieve proper EMI shielding effectiveness, and poor mechanical properties. This paper introduces main methods to manufacture CPCs with segregated filler structure, which can significantly reduce the filler content, and analyzes EMI shielding performance of each manufacturing method.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.497-500
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• 1998

고분자 물질에 처리하는 전자기파 차폐처리 방법으로서 무전해 도금법은 차폐 처리하고자 하는 매트릭스 표면에 균일한 금속 필름을 형성할 수 있으며 차폐효과가 크고 시료의 형태가 복잡하여도 응용 가능한 가공방법으로 알려져 있다. [1,2] 무전해 구리 도금의 경우, 도금용액 중에 포함되는 환원제의 산화반응에 의해 유리되는 전자에 의하여 금속이온을 환원함으로써 금속 피막을 석출시키며 이때 일어나는 반응 메카니즘은 다음과 같다. [3] (중략)

• Journal of the Korea Concrete Institute
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• v.28 no.2
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• pp.197-204
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• 2016

Concrete walls of neutron generating facilities such as fusion reactors and fission reactors become radioactive by neutron irradiation. Both low-activation and neutron shielding are a critical concern at the dismantling stage after the shutdown of facilities with a requirement of radioactive waste management. To tackle this, two types of additives were investigated in fabricating mortar specimens: synthetic high polymers and boron carbide. It is well known that a hydrogen atom is effective in neutron shielding by an elastic scattering because its mass is almost the same as that of the neutron. And boron is an effective neutron absorber with a big neutron absorption cross section. In this study, the effect of the type, shape, and size of polymers were investigated as well as that of boron carbide. Total 16 mix designs were prepared to reveal the effect of polymers on mechanical properties and neutron shielding performance. The neutron does equivalent of polymers-based mortar for fast neutrons decreased by 36 %, and the count rate of boron carbide-based mortar with regard to thermal neutrons decreased by 90 % compared to conventional mortar. These results showed that a combination of polymers and boron carbide compounds has potential to reduce the thickness of neutron shields as well as radioactive waste from reactors.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.687-695
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• 2022

To find a 3D printer material that can replace lead used as a shield for high-energy electron beam treatment, the shielding composites were simulated by using MCNP6 programs. The Percent Depth Dose (PDD), Flatness, and Symmetry of linear accelerators emitting high-energy electron beams were measured, and the linear accelerator was compared with MCNP6 after simulation, confirming that the source term between the actual measurement and simulation was consistent. By simulating the lead shield, the appropriate thickness of the lead shield capable of shielding 95% or more of the absorbed dose was selected. Based on the absorption dose data for lead shield with a thickness of 3 mm, the shielding performance was analyzed by simulating 1, 5, 10, and 15 mm thicknesses of ABS+W (10%), ABS+Bi (10%), and PLA+Fe (10%). Each prototype was manufactured with a 3D printer, measured and analyzed under the same conditions as in the simulation, and found that when ABS+W (10%) material was formed to have a thickness of at least 10mm, it had a shielding performance that could replace lead with a thickness of 3mm. The surface morphology and atomic composition of the ABS+W (10%) material were evaluated using a scanning electron microscope (SEM) and an energy dispersive X-ray spectrometer (EDS). From these results, it was confirmed that replacing the commercialized lead shield with ABS+W (10%) material not only produces a shielding effect such as lead, but also can be customized to patients using a 3D printer, which can be very useful for high-energy electron beam treatment.