• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.384-391
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• 2012

In this paper, reinforced concrete structures are modeled and analyzed. Reinforced concrete has been an essential element in the construction and one that is provided for shielding effectiveness at particular frequencies by rebar placed as a set up in the form of a grid. Using commercial 3-dimensional electromagnetic(3D EM) tool to analyze the reinforced concrete structure, the procedure of analysis for reinforced concrete is computed by dividing concrete, rebar and entire reinforced concrete. The spacing of rebar is bigger, transmission coefficient is higher and the diameter of rebar is bigger, transmission coefficient is lower. Also, in case of two layers is analyzed by gap of layers. Using single layer rebar that thickness of rebar given by 10, 20 and 30 mm have transmission coefficient of -1.89, -2.73 and -4.76 dB/10 cm at 500 MHz. Also, two layers rebar obtain -1.89, -2.73 and -4.76 dB/10 cm for same conditions.

• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.713-718
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• 2018

In many previous studies, monte carlo simulation is used to produce lead-free shielding sheet, and the possibility of radiation shielding capability and weight reduction is presented. But it is difficult to simulation for binder and micro-pores because of In fact it does not provide sufficient information necessary for the commercialization process. Therefore, in this paper, the results of radiation shielding capability corresponding to filling factor was presented by using the screen printing method to provide information on gel-paste required for the commercialization process. In this study, the geometric setup for evaluate of radiation shielding ability was designed to comply with IEC 61331-1:2014 and KS A 4025. In addition, radiation irradiation conditions were 100 kVp filtered with 2.0 mmAl total filtration was applied according to KS A 4021 standard. In this study, Pb $1270{\mu}m$, $BaSO_4$ $3035{\mu}m$, $Bi_2O_3$ $1849{\mu}m$ and $WO_3$ $2631{\mu}m$ were analyzed based on ten value layer. Additionally, the filling factor was analyzed as $BaSO_4$ 38.6%, $Bi_2O_3$ 27.1%, $WO_3$ 30.15%. However, in the case of applying low-temperature high-pressure molding in the future, it is expected that the radiation shielding capability can be sufficiently improved by reducing the porosity while increasing the filling factor.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.159-165
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• 2015

The article presents a parametric study on geometrical design optimization for coupling the joint between a large exhaust air chimney and electromagnetic pulse (EMP) shield for gas turbine electricity generator. We conducted computational fluid dynamics (CFD) simulations on hydraulic diameters of waveguide below cutoff(WBC) ranges 800mm~1025mm, the connection distance ranges 150~450mm, and exhaust gas flow velocities at 15, 20, and 25m/s. The results show that the diameter of main chimney, connection distance, and exhaust gas velocity had impacts on flow stream at the EMP shield. To provide a fully developed stream line at three different flow velocity cases, the WBC diameter and distance of connection should be larger than 1050mm and longer than 300mm, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.652-659
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• 2012

Shielding effectiveness(SE) of metallic rectangular enclosure with rectangular slit apertures at horizontal polarization (HP) and vertical polarization(VP) is investigated. The magnetic polarizability of the rectangular slit apertures and the resonance modes of the metallic rectangular enclosure are analyzed theoretically. The simulation results based on these theoretical analyses are compared with the measured ones. The dependence of the shielding effectiveness on the location of the calculation probe inside the enclosure is also investigated.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.429-435
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• 2017

In order to increase the therapeutic effect of radiation, there has been an increase in the use of conventional photon therapy. The intensive care unit should pay more attention to the radiation safety evaluation due to the higher energy and the larger facility compared to the existing Photon treatment. These radiation safety evaluations are mainly performed by using Monte Carlo simulation, and the first thing to be done is geometric modeling. The Heavy-ion treatment facility uses synchrotron as the accelerating device, which is difficult to precisely model geometrically and is mostly modeled briefly. This study investigated the effect of simplification and precise implementation of Dipole magnet among the components of synchrotron acceleration device on the radiation safety evaluation. The results show that the simplified geometric model is overestimated with the precisely implemented geometric model. Therefore, it is considered that the radiological safety evaluation results in more reliable results of the precise geometric modeling.

• Journal of Astronomy and Space Sciences
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• v.18 no.1
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• pp.71-80
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• 2001

The threshold voltage shift observed in TDE (Total Dose Experiment) on board the KITAT-1 is converted into dose (rad($SiO_2$)) using the result of laboratory calibration with Co-60 gamma ray source in KAERI (Korea Atomic Energy Research Institute). Simulation using the NASA radiation model of geomagnetosphere verifies that the dose difference between RADFET1 and RADFET3 observed on KITSAT-1 comes from the difference in shielding thickness at the position of these RADFETs.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.455-461
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• 2002

가공 송전선로의 낙뢰고장은 송전설비가 국토 전 지역에 분포되어 있기 때문에 고장 점유율이 가장 높다. 또한 낙뢰가 아주 큰 전기량과 짧은 순간에 방전하는 특성뿐 아니라 다양한 구름의 변화형태에 따른 낙뢰 발생 패턴이 달라 아직까지 이를 예방하거나 제어하는 기술은 높지 않은 수준에 있다. 이 논문은 자연환경이 비슷하고 전압레벨과 전력계통이 유사한 한국전력(KEPCO)과 대만전력(TPC)의 6년간의 송전선로 낙뢰고장을 통계적으로 비교하여 낙뢰고장과 전력신의 차례각과의 관계적 원인을 도출하고자 하였다. 이에 따라 전력선의 차폐각에 따른 낙뢰고장 발생 확률을 시뮬레이션 프로그램을 통하여 도출하고 실제 양 전력회사의 차폐각별 송전선로의 낙뢰고장 발생빈도와 비교하였다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.114-115
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• 2018

To develop an effective shielding material for spent fuel that emits fast neutrons is necessary. In this study, thermal neutron and fast neutron shielding performance of polyethylene coated boron carbide-incorporated cement paste was quantitatively analyzed by Monte Carlo N-Particle transport code (MCNP) simulations. As the results of the simulations, fast neutrons were effectively shielded through large quantity of hydrogen and boron elements in polyethylene and boron carbide.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.559-563
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• 2016

Recently, a barium(Ba) and an iodine(I) being studied as a conventional lead(Pb) alternatives of shielding material has excellent shieding rate, but the characteristic x-ray photons in the energy range near 30 keV line is released. In this study, with bismuth oxide(BiO) coupled barium sulfate($BaSO_4$) double layer, transmitted spectra, shieding rates and relative weighting rates were evaluated to validate the applicability of eco-friendly double layer shieding structure using monte carlo simulations as a prior study. From the evaluation results, in 0.4mm and 0.5mm thickness of BiO layers coupled with top 0.1mm-$BaSO_4$ layer, the shieding rate showed 1.9% and 3.9% higher than 0.6mm thickness of Pb single layer, respectively. In addition, the relative weight also 28% and 34.5% lower than 0.6mm-Pb in 0.4mm and 0.5mm thickness of BiO layers coupled with top 0.1mm-$BaSO_4$ layer.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.316-322
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• 2019

A probabilistic approach considering uncertainties was employed to investigate the effects on the material characteristics and strength of nuclear bio-logical shield concrete walls, when exposed to long-term radiation during the entire service life. Time-dependent compressive and tensile strengths were estimated by conducting the neutron fluence analysis. For the contaminated concrete, individual compressive and tensile failure probabilities can be possibly evaluated by not only establishing limit-state function withthe predefined critical values but also performing Monte Carlo Simulation. Nuclear power plant types similar to the Kori Unit 1, which was shut off permanently in 2017 after the 40-year operation, were herein selected for an illustrative purpose. Consequently, the probability-based performance assessment and prediction of contaminated concrete walls were well demonstrated.