• Textile Coloration and Finishing
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• v.16 no.5
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• pp.42-47
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• 2004

The main objective of this work is to develop melt-blown nonwoven fabric composite materials have electromagnetic shielding characteristics using thin copper film. Melt-blown nonwoven fabric is the matrix phase and thin copper films are the reinforcement of the composite materials. Thin copper films are incorporated as conductive fillers to provide the electromagnetic shielding property of the melt-blown nonwoven fabric. The width and interval of thin copper films in the nonwoven fabric are varied by changing 1, 3, 5 mm for thin copper film's width and 1, 3, 5 mm for thin copper film's interval. The shielding effectiveness(SE) of various melt-blown nonwoven fabrics is measured in the frequency range of 50 MHz to 1.8 GHz. The variations of SE of melt-blown nonwoven fabric with width and interval of thin copper films are described. Suitability of melt-blown nonwoven fabric for electromagnetic shielding applications is discussed. The results indicate that the melt-blown nonwoven fabric composite material using thin copper film can be used for the purpose of electromagnetic shielding.

• Journal of the Korea Institute of Building Construction
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• v.13 no.1
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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.

• Journal of Ocean Engineering and Technology
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• v.23 no.3
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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.

• Polymer(Korea)
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• v.27 no.3
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• pp.201-209
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• 2003

DC and AC electrical conductivity and electromagnetic interference shielding effectiveness of milled carbon fiber/nylon composites were investigated with the kind of nylon matrix. Percolation transition at which the conductivity is sharply increased was observed at about 7 vol% of milled carbon fiber. Nylon 46 as a matrix was more effective to obtain high electrical conductivity than nylon 6, and the difference in conductivity was occurred by the treatment of coupling agent. Frequency dependence of AC conductivity could be explained by relaxation phenomenon at just below percolation and resonance phenomenon at 40 vol% of carbon fiber, respectively. Negative temperature coefficient phenomenon was found in all composites. Electromagnetic interference shielding effectiveness was increased with the concentration of carbon fiber. At a high conductivity region the return loss was more dominant to the total shielding effectiveness than the absorption loss.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.1
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• pp.63-69
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• 2016

This paper presents methods to improve the effectiveness of electromagnetic shielding. The slit appears in an enclosure's surface to ventilate. Slits may also appear due to power supply lines or to serve as a communication link between electronic circuits inside and outside the box. We simulated electromagnetic radiation in different conditions in order to propose a method to improve the effectiveness of electromagnetic shielding to ensure electromagnetic compatibility using CST software (Computer Simulation Technology).

• Journal of Satellite, Information and Communications
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• v.3 no.1
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• pp.35-40
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• 2008

In this paper, a new analytical formulation is presented for calculating shielding effectiveness (SE) of shielding enclosure including satellite electronic components and equipments. The shielding enclosure has a dielectric-backed aperture. The SE may be a function of frequency, dielectric constant, and position within the enclosure. And, the formulation has been extended for calculation of the SE of the structure where the one side of dielectric is partially backed by conductor. Our simulation results give that the dielectric material lowers the Q factor, and the further the observation point is from the aperture, the more SE increases.

• Journal of Magnetics
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• v.13 no.4
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• pp.173-176
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• 2008

In this study, a new kind of instrument for measuring the magnetic shielding effectiveness (MSE) was developed using a double yoke; one a magnetizing yoke and the other a sensing yoke. Using the developed instrument, the MSE could be measured for a steel sheet specimen in the ELF range, where the magnetic permeability contributes to the MSE at low frequencies and eddy currents contributes to the MSE high frequencies with < 0.1 dB reproducibility. The developed measuring method can be applied to quality control in a steel sheet company producing EMI/EMC shielding materials.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.150-151
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• 2015

In this study, the electromagnetic shielding performance of mortar with different metal fiber, as part of the development of a electromagnetic shielding construction material, was measured according to KS C 0304. The results showed that the amorphous steel fibers can shield electromagnetic effectively than the oter conventional steel fibers. The superior performance of the amorphous steel fiber may be attributed its plate shape geometry.

• Journal of Radiation Protection and Research
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• v.43 no.1
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• pp.20-28
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• 2018

Background: Heat energy produced in nuclear reactors and nuclear fuel cycle facilities interactions modifies the physical properties of the shielding materials containing water content. Therefore, in the present paper, effect of the heat on shielding effectiveness of the concretes is investigated for gamma and neutron. The mass attenuation coefficients, effective atomic numbers, fast neutron removal cross-section and exposure buildup factors. Materials and Methods: The mass attenuation coefficients, effective atomic numbers, fast neutron removal cross-section and exposure buildup factors of ordinary and heavy concretes were investigated using NIST data of XCOM program and Geometric Progression method. Results and Discussion: The improvement in shielding effectiveness for photon and reduction in fast neutron for ordinary concrete was observed. The change in the neutron shielding effectiveness was insignificant. Conclusion: The present investigation on interaction of gamma and neutron radiation would be very useful for assessment of shielding efficiency of the concrete used in high temperature applications such as reactors.

• Proceedings of the KSME Conference
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• 2004.11a
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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.