• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.59-65
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• 2019

The EMI shielding effectiveness of shielding layers thickness was analyzed when the low conductivity shielding layers was placed in the near field of the noise source. A spiral antenna with broadband characteristics was used as the noise source, and graphite was selected as the low conductivity shielding material. Two spiral antennas were constructed to analyze the transmission coefficient between two antennas, and the distances between the transmitting and receiving antennas were 5 cm and 10 cm. The thickness of the shielding layers was changed from 1 um to 200 um. The frequency was changed from 100 MHz to 6 GHz to obtain a maximum SE(Shielding Effectiveness) of 70 dB. In this simulation, electronic shielding was used due to the nature of graphite, which is a shielding film material. Based on these results, we will study how to improve the shielding performance by implementing magnetic shielding in the future.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.119-126
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• 2021

Radiation shielding clothing for medical institutions is used based on lead equivalent of 0.25 mmPb. However, this study intends to study the shielding suit that can guarantee the user's activity while considering the sensitivity of each part of the body. By manufacturing based on eco-friendly shielding material, it was attempted to solve the weight problem and environmental problem of existing lead aprons, and to present the same shielding performance as lead equivalent in thickness. The fabric of the produced shielding sheet was manufactured through a calendar process that adjusts the thickness of the shielding sheet from lead equivalent 0.12 mmPb to 0.32 mmPb. In addition, the usability evaluation of the manufactured shielding clothes was conducted for the subjects who were workers in medical institutions. As a result, the activity became easier and the weight was reduced by 0.26 kg. In the future, it is thought that it is necessary to improve the shielding suit design considering the activity.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.86-91
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• 2016

Convenient design guideline for Waveguide-below-cutoff (WBC) array is proposed to obtain the minimum waveguide length for electromagnetic pulse (EMP) shielding. The analysis includes circular, rectangular, and hexagonal WBC, determine the total length of the waveguide. When the unit side of rectangular WBC and the diagonal line of hexagonal WBC are given as 30 mm, the length of hexagonal WBC is 5 mm shorter than rectangular case with shielding effectiveness (SE) 80 dB. The length difference is deepened with SE of 100 dB, which shows approximately 30 mm shorter length for hexagonal case than others. In addition, hexagonal WBC requires much shorter length than circular WBC. In conclusion, hexagonal case is the most effective with respect to flow velocity and pressure loss for equivalent SE.

• Journal of the Korean Society of Radiology
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• v.5 no.3
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• pp.135-141
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• 2011

If protective performance of apron cannot be good, radiation exposure of an guardian or a patient, a person engaged in radiation related industry cannot rise. Therefore, It will be evaluated protection performance to radiation protection aprons by manufacturers and lead equivalent more than 0.25mm lead equivalent. And, will show in the direction of application to clinic. The new aprons by manufacturers(H, X, I, J company) and lead equivalent(0.50mmPb, 0.35mmPb, 0.25mmPb) measured transmitted dose rate and shielding rate, uniformity under fluoroscopy and general radiography using to fluoroscopy system and digital radiography system, x-ray multifunction meter. The shielding rate measurement results, 0.5mmPb apron was Shielding rate of apron of a I company(fluoroscopy : 97.96%) was the best under six companies, and shielding rate of apron of a J company(fluoroscopy : 96.25%) was worst. 0.35mmPb Apron was Shielding rate of a I company(fluoroscopy : 96.79%) was the best under the three companies, and shielding rate of an H company(fluoroscopy : 95.81%) was the worst. 0.25mmPb Apron was Shielding rate of X company apron(fluoroscopy : 90.908%) was better than H company apron(fluoroscopy : 88.82%) than two companies. The uniformity measurement results, 0.5mmPb Aprons of X company(fluoroscopy : 0.13) and I company(fluoroscopy : 0.19) was the best under the six companies, and J company apron(fluoroscopy : 0.45) was the worst. 0.35mmPb. Along a manufacturer and lead equivalent performance of apron protection is distinguished certainly. Therefore, a patient, guardian or a person engaged in radiation related industry shall enforce experiment of a lot of ways defined or evaluation so that the maximum reduces radiation exposure. Buy the apron that protective performance is good, It will be performed through experiment and evaluation.

• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.8-9
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• 2011

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.95-101
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• 2017

In this paper, the sizing removal condition for the pretreatment of composite materials is obtained numerically by applying an image processing algorithm and nickel-plated carbon fiber is fabricated by a dry process method to enhance its electromagnetic shielding performance. Sizings that are wrapped in a polymer type material during the manufacturing of carbon fiber should be removed for dry coating. A numerical value, that is the correlation, can be obtained by determining the regular pattern of the carbon fiber in the image taken by a scanning electron microscope (SEM) after the sizing is removed. The application of the proposed numerical method to the SEM image of the fiber after the sizing is removed with solution, compressed air, solution and compressed air (hybrid), showed that this method of eliminating the sizing is superior to the hybrid method. Then, by spreading the carbon fiber roll with the sizing removed, we were able to produce nickel plated carbon fiber by the roll-to-roll sputtering method. The electromagnetic shielding performance of the fabricated 30, 40 and 100 nickel coated carbon fibers was measured. The Korea Advanced Institute of Science and Technology evaluated the electromagnetic shielding performance of the 100 nickel-coated carbon fiber to have a maximum value of 73.2 (dB) and a minimum value of 66.7 (dB). This is similar to the electromagnetic shielding rate of copper and shows that this material can be used as a cable for EV / HEV automobiles.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.124-125
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• 2017

In this study, the shielding effectiveness of the Zn-Al arc thermal metal film coated cement-mortar mixed with copper powder by reflection, absorption, multi-reflection loss in 2.25~2.65 GHz was reviewed. By enhancing the mixing ratio of copper powder, the shielding effectiveness by absorption and multi-reflection loss was increased, but shielding rate(%) based on 80 dB showed below 20%. The Zn-Al arc thermal metal film coated on specimen, the shielding rate increased 3.5 times by reflection loss.

• Journal of radiological science and technology
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• v.33 no.2
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• pp.121-126
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• 2010

Traditionally, lead has been primarily used to shield the radiation in the hospital, because of its soft texture, durability and cost effectiveness. However, lead can be dangerous because of its toxicity when exposed to the human body, and it is classified as a heavy metal like cadmium, mercury, and arsenic etc. In order to compensate its noxious properties on the human body, researchers are trying to develop a radiation shield which has similar shielding efficiency and can also be manufactured in any form. In this study, sulfuric acid barium was mixed with fiber, rubber, and silicon all of which are harmless to the human body, tested, and evaluated for its ability of medical radiation shield. The result of this study showed that the sheet containing silicon and barium has the strongest shielding abilities.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.10
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• pp.1171-1177
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• 2014

An electromagnetic shielding doorset must satisfy requirements associated with both mechanical strength/durability and electromagnetic shielding. Among the primary components of the doorset, a finger strip-a leaftype spring normally made of beryllium copper-is a core part to shield electromagnetic waves as well as to endure repetitive dry sliding friction. This study presented a reliability demonstration test method for the doorset system and, by a simple and simultaneous implementation, of the replacement interval of the finger strip. A rigorous evaluation for the qualification of maintenance or replacement interval is included in the reliability demonstration test of any series system that holds critical maintenance sub-units.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.4
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• pp.101-108
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• 2015

The quantities of heavy weight waste glass have been progressively increased because of the rapid industrialization and the change of quality of life. And, the most of them are not recycled. The heavy weight waste glass have been treated by illegal dumping or being buried in landfills. Meanwhile, in order to ensure the safety of nuclear power plant structure, the excellent construction materials are socially required for shielding performance. Concrete is the most widely used construction material, the huge amounts of natural resources are required to make concrete. So, it is needed to investigate the possibility of recycling of heavy weight waste glass as concrete material ingredient. In this study, the heavy weight waste glass was evaluated for the applicability as fine aggregate of shielding concrete. From the results, when heavy weight waste glass was replaced as fine aggregate of mortar, shielding performance can be improved due to increasing in unit weight of mortar. It showed that the strength decreased according to mixing of heavy weight waste glass, Non-Washed heavy weight waste glass is more advantageous in the strength development than Washed case.