• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.4
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• pp.11-19
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• 1995

In this paper, the Finite Difference Time Domain (FDTD) method is used to analyse the characteristics of the coaxial line transmission coefficent, shielding effectiveness, and compared to results of the moment method. The excitation mode of the Gaussian pulse is assumed to be a TEM-mode instead of the TE or TM-mode and in order to eliminate the reflected wave with in short length of the line. Calculated value of shielding effectiveness of the coaxial line by the FDTD are in good agreement with the results of the moment method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.1
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• pp.60-66
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• 2009

A new analytical method is presented for the shielding effectiveness(SE) of an enclosure with a dielectric-backed aperture. The previously proposed methods cannot consider the effect of the dielectric on the aperture. The comparisons among our method, previous method, and commercial programs give good correspondence. The method is used to calculate SE with varying permittivity and thickness of dielectric sheet, probe position, width and height of aperture.

• Journal of Radiation Protection and Research
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• v.14 no.1
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• pp.46-55
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• 1989

Neutron shielding for a spent fuel container was analized using the Monte Carlo code MCNP coupled with discrete ordinates codes, XSDRN and ONEDANT. The ORIGEN-S code was used to determine the fixed neutron source, and the spectral source information for MCNP were obtained from a 10 group XSDRN calculation and a 27 group ONEDANT calculation. When the depleted uranium shield was used, the results from ONEDANT and XSDRN calculations agreed with the MCNP results within 10% and 20%, respectively. Depleted uranium appears more effective than lead or steel as a neutron shield.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.492-498
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• 2021

In this paper, the electromagnetic wave transmittance of the reinforced concrete structure wall was analyzed using the performance measurement system of electromagnetic wave shielding. Recently, electromagnetic wave shielding technologies on the reinforced concrete wall conditions have been studied, and the shielding effectiveness have been tested on unit cell size. However, the unit cell size tests have problems on that the measurement range for shielding performance is insufficient and it is difficult to reflect the real conditions of the concrete wall. Therefore, we constructed a shielding performance measurement system using a large sample of 2.2m × 2.2m like a real wall. To verify the measurement system, general reinforced concrete test samples were selected, and real shielding performance measurements and numerical analysis were proceeded. Test and numerical analysis results showed similar tendencies in the evaluation frequency range of 75MHz to 2GHz. Thus we validated the effectiveness of this shielding performance measurement system.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.51-62
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• 1993

A computational program ［TDET］ of the particle transport equation is developed on radiation shielding problem in two-dimensional cartesian geometry based on the discrete element method. Not like the ordinary discrete ordinates method, the quadrature set of angles is not fixed but steered by the spatially dependent angular fluxes. The angular dependence of the scattering source term in the particle transport equation is described by series expansion in spherical harmonics, and the energy dependence of the particles is considered as well. Three different benchmark tests are made for verification of TDET : For the ray effect analysis on a square absorber with a flat isotropic source, the results of TDET calculation are quite well conformed to those of MORSE-CG calculation while TDET ameliorates the ray effect more effectively than S$_{N}$ calculation. In the analysis of the streaming leakage through a narrow vacuum duct in a shield, TDET shows conspicuous and remarkable results of streaming leakage through the duct as well as MORSE-CG does, and quite better than S$_{N}$ calculation. In a realistic reactor shielding situation which treats in two cases of the isotropic scattering and of linearly anisotropic scattering with two groups of energy, TDET calculations show local ray effect between neighboring meshes compared with S$_{N}$ calculations in which the ray effect extends broadly over several meshes.eshes.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.190.1-190.1
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• 2010

풍력자원평가를 위해 풍력단지 개발대상지의 국지풍황 대표지점에 설치하는 풍황탑(met-tower 또는 풍황마스트; met-mast)은 모노폴(monopole), 삼각단면 트러스 또는 사각단면 트러스 구조를 갖는다. 풍향계 및 풍속계는 이러한 지지구조물에 의한 풍속의 교란 또는 차폐영향을 최소화하기 위하여 긴 붐(boom)의 끝단에 설치되지만 계측기가 풍황탑의 직후방 후류영역에 놓이게 될 경우 차폐영향을 완전히 피하기는 어렵다. 저자들의 선행연구에 따르면 풍황탑 차폐영향은 평균풍력밀도의 경우 2.5% 이상의 오차를 유발할 수 있으므로 풍력자원평가 시 필히 고려되어야 할 불확도 요인인 것이다. 이에 한국에너지기술연구원에서는 풍황탑 주위의 대기유동장을 전산유동해석을 이용하여 차폐영향의 정도를 정량적으로 수치모사함으로써 이를 보정하는 기술을 개발한 바 있다(현재 특허심사 중). KIER-$ShadeFree^{TM}$는 이 특허기술을 프로그램화 한 것으로, 시범적으로 다수의 풍황탑 풍력자원 측정자료에 적용하여 상당한 보정효과에 의한 풍력자원평가의 정확도 향상효과를 볼 수 있었다.

• Nuclear Engineering and Technology
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• v.20 no.1
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• pp.65-70
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• 1988

A Shielding analysis of the shipping cask designed conceptually, of which shielding material are lead and resin, for containing 4 PWR spent fuel assemblies, has been made with the help of a computer code, ANISN. The shielding materials being used in the cask have been selected and arranged to minimize cask weight while maintaining an overall shielding effectiveness. Radiation source terms have been calculated by means of ORIGIN-2 code under the assumptions of 38,000 MWD/MTU burnup and 3-year cooling time. A calculation of gamma-ray and neutron dose rates on the cask surface and 1m from the surface has been done. It is revealed that the total dose rates under the normal transport and hypothetical accident conditions meet the standards specified.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.719-726
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• 1999

Multiconductor transmission line(MTL) equations are solved by FDTD method to examine the coupling between incident electromagnetic fields and multiconductor transmission lines. The measurement of induced voltages on UTP Category 5 and STP Category 5 cables which are used as LAN cables is carried out using a TEM cell where uniform and strong TEM fields can be established. The comparison between measured and simulated results shows good agreement. It is also found that grounding of shield foil at both terminations and small grounding resistance give good shielding effects for STP Category 5.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2036-2037
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• 2007

반사형 펄스와전류(Pulsed Eddy Current; PEC) 탐상을 위한 여러 가지 탐촉자를 설계하고, 수치해석 방법을 사용하여 신호특성과 두께변화에 대한 만감도를 조사하였다. 구리와 페라이트를 차폐체로 사용한 결과, 구리로 차폐한 여자코일이 페라이트로 차폐한 센서코일보다 안쪽에 있는 것이 두께변화에 더 민감하였고, 페라이트만으로 차폐한 경우에도 여자코일이 안쪽에 있는 것이 더 민감하다는 것을 알 수 있었다. 한편, 두께가 두꺼워지면 펄스신호의 피크치는 감소하며 피크 발생시간이 변화하는 것을 관찰할 수 있었다.

• Journal of the Korean Magnetics Society
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• v.9 no.1
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• pp.55-63
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• 1999

It is necessary to eliminate the broad band noise whose frequency is in the range of several kHz to tens MHz generated from the AC power line to supply the power to electrical and electronic equipments. Because this kind of noise could damage or malfunction such equipments. To suppress those noises, some conventional devices such as a filter or surge suppressor have been used. However, they can not be isolated from the common-mode noise widely spreaded in all power line, which results in poor common-mode rejection performance. In this paper, we proposed a design method of shielded isolation transformer and a jumped circuit analysis model for shielded isolation transformer applicable to filtering common-mode noise as well as normal-mode noise. The analysis model has been verified as a suitable one for shielded isolation transformer through comparison of the simulation with experiment. In addition, it has been shown that the reduction performance for conducted noise of prototype 3 kVA shielded isolation transformer is superior to a unshielded isolation transformer.