• Title/Summary/Keyword: Shielding Equation

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Prediction of Shielding Effectiveness in Honeycomb Structure Using the Modified Design Equation (수정된 설계 방정식을 이용한 허니컴 구조의 차폐 효과 예측)

  • Lee Kyung-Won;Cheong Yeong-Chul;Hong Ic-Pyo;Yook Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.9 s.100
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    • pp.862-871
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    • 2005
  • In this paper, the modified design equation of shielding effectiveness was presented to predict more accurately the shielding effectiveness of honeycomb structure with hexagonal waveguide. The design equation of shielding effectiveness in honeycomb was represented from adding shielding effectiveness of single lattice to shielding effectiveness of infinite array of single lattice. This paper proposed the generalized design equation of shielding effectiveness by analyzing basis lattice of hexagonal waveguide which composes honeycomb structure and infinite array structure of basis lattice. To provide the validity of the modified design equation of shielding effectiveness in this paper, comparison with other available date using 3D EM commercial software is made.

A Study on Laminated Shielding (박판접합에 의한 전자기파의 차폐)

  • Noh-Hoon Myung
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.2 no.2
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    • pp.25-29
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    • 1991
  • In this paper, laminated shielding effectiveness equation is derived from basic shielding theory and this equation is applied to calculate the shielding effectiveness for two typical non-magnetic shielding materials, Aluminium and steel, when they are coated with conductive paint.

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Analysis of EMP Shielding with Multi-Layered Waveguide-Below-Cutoff Array Using Modified Shielding Effectiveness Equation (수정된 차폐효과 방정식을 이용한 다층 구조 도파관의 EMP 차폐 분석)

  • Kim, Sangin;Kim, Yuna;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.6
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    • pp.452-458
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    • 2017
  • Multi-layered Waveguide-Below-Cutoff Array(WBCA) used in air duct and water pipe has advantages in manufacturing process as well as flow characteristics. In addition, it is possible to increase the Shielding Effectiveness(SE) by increasing the number of layers. However, since the SE of the multi-layered WBCA can not be predicted by the conventional SE equation, we propose the modified SE equation. The modified SE equation is obtained for both air and arbitrary fluid flowing in a multi-layered WBCA by increasing the number of layers from 2 to 64. In order to confirm the validity, the results of the proposed SE equations are compared with the EM simulation results.

Analysis of Dynamic Behavior in GMAW System (GMA용접 시스템의 동적 거동에 대한 해석)

  • 이재영;최재형;이지혜;유중돈
    • Journal of Welding and Joining
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    • v.18 no.5
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    • pp.41-48
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    • 2000
  • Dynamic behaviors of the GMAW system are simulated using the short-circuit transfer model and the characteristic equations fir the power supply, wire system and arc. The conventional wire equation, which relates the rate change of the wire extension to the wire feed rate and melting rate, is modified to include effects of the molten drop attached at the wire tip. The modified wire equation describes behaviors of the GMAW system more precisely and provides information about the initial bridge volume for short-circuit transfer. The proposed short-circuit model predicts the variation of parameters such as the current, voltage, short-circuit frequency and time considering the effects of the surface tension and electromagnetic force due to current. The calculated results are in broad agreements with the experimental results under the argon shielding condition.

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Green synthesis of Lead-Nickel-Copper nanocomposite for radiation shielding

  • B.M. Chandrika;Holaly Chandrashekara Shastry Manjunatha;R. Munirathnam;K.N. Sridhar;L. Seenappa;S. Manjunatha;A.J. Clement Lourduraj
    • Nuclear Engineering and Technology
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    • v.55 no.12
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    • pp.4671-4677
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    • 2023
  • For the first time Pb, Ni, and Cu nanocomposites were synthesized by versatile solution combustion synthesis using Aloevera extract as a reducing agent, to study the potential applications in X-ray/gamma, neutron, and Bremsstrahlung shielding. The synthesized Lead-Nickel-Copper (LNC) nanocomposites were characterized by PXRD, SEM, UV-VIS, and FTIR for the confirmation of successful synthesis. PXRD analysis confirmed the formation of multiphase LNC NCs and the Scherrer equation and the W-H plot gave the average crystal sizes of 19 nm and 17 nm. Surface morphology using SEM and EDX confirmed the presence of LNC NCs. Strong absorption peaks were analyzed by UV visible spectroscopy and the direct energy gap is found to be 3.083 eV. Functional groups present in the LNC NCs were analyzed by FTIR spectroscopy. X-ray/gamma radiation shielding properties were measured using NaI(Tl) detector coupled with MCA. It is found to be very close to Pb. Neutron shielding parameters were compared with traditional shielding materials and found LNC NCs are better than lead and concrete. Secondary radiation shielding known as Bremsstrahlung shielding characteristics also studied and found that LNC NCs are best in secondary radiation shielding. Hence LNC NCs find shielding applications in ionizing radiation such as X-ray/gamma and neutron radiation.

A Study of Shielding Property of Magnetic Field for the Film Impregnated with Soft Magnetic Powder (연자성 합금분말을 함침시킨 필름의 자계 차폐 특성 연구)

  • Park, Jong-Hyun;Ra, Keuk-Hwan;Kang, Eun-Kyun;Kim, Jin-Woo
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.1
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    • pp.211-218
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    • 2014
  • In this paper the magnetic field properties of the soft magnetic alloys (Fe-Si-Cr and Fe-Ni-Cr) are studied in advance for the development of electro-magnetic shielding films, which could be used in the IT Devices (NFC, mobile phone, computer, etc.).As a result each of the selected soft magnetic alloy melts of the corresponding compositions is water-dispersed into the disk-shaped grains, which are soaked in polymer resin, and of which two types of thin film of thickness 0.1mm and 1mm are made by passing through the heating calendar roller. And the magnetic permeability and the shielding effectiveness of the polymer films containing the soft magnetic alloy grains are measured over the whole frequency bands from the low frequency to 10GHz. Before the experiments of the soft magnetic alloy, a special equation is proposed to estimate the permeability of the alloy, and the equation is verified with the pre-published data by MATLAB, and from which the most optimal compositions can be decided. And the SE(Shielding Effectiveness) of the polymer films containing the soft magnetic alloy grains is simulated by the HFSS.

Shielding effectiveness of an Aperture in Infinite Conducting plane Due to HEMP Incidence (무한 도체평판 개구에 입사하는 HEMP 파형에 따른 침투 전자파의 차폐효과)

  • Lim, Byoung-Jin;Seo, Hun-Wook;Lim, Sung-Min;Kim, Ki-Chai
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.8
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    • pp.1647-1652
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    • 2011
  • This paper presents the shielding effectiveness for the IEC 61000-2-9 standard when HEMP source penetrates through an aperture in a planar conducting plane of infinite extent. An integral equation is derived and solved by applying Galerkin's method of moments for calculating the electric shielding effectiveness. The electric shielding effectiveness is examined based on changing the aperture length and width. It is shown that the electric shielding effectiveness is suddenly decreases as the aperture width of 0.4 ~ 0.45${\lambda}$. It is also found that the penetrated electric field for the IEC 61000-2-9 incident field is different from the Bell Laboratory incident field, but the frequency characteristic of the electric shielding effectiveness becomes the same shape.

Shield Ratio and Thrust Performance Analysis According to The S-Type Nozzle of The Centerline Shape (S-형 노즐 형상의 중심선 형태에 따른 차폐율과 추력 성능 해석)

  • Jin, Juneyub;Park, Youngseok;Kim, Jaewon;Lee, Changwook
    • Journal of the Korean Society of Propulsion Engineers
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    • v.25 no.3
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    • pp.42-55
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    • 2021
  • In this study, the effect of nozzle performance according to the selection of the center line equation. Three of S-type nozzles and three of double S-type nozzles were designed using the curve equation and design parameters, and the nozzle shielding performance was evaluated using the shielding ratio definition. In order to analyze the internal flow of the nozzle, the characteristics of the velocity distribution and pressure distribution were studied, and the nozzle performance was evaluated through the total thrust ratio(f) and the nozzle insulation efficiency coefficient(η). On the other hand, the centerline with a sharply change in curvature at the entrance has a low nozzle performance and a high shielding rate. The double S-type nozzle is excellent nozzle performance and shielding rate by using a smooth centerline at the first curvature.

A closer look at the structure and gamma-ray shielding properties of newly designed boro -tellurite glasses reinforced by bismuth (III) oxide

  • Hammam Abdurabu Thabit;Abd Khamim Ismail;N.N. Yusof;M.I. Sayyed;K.G. Mahmoud;I. Abdullahi;S. Hashim
    • Nuclear Engineering and Technology
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    • v.55 no.5
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    • pp.1734-1741
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    • 2023
  • This work presents the synthesis and preparation of a new glass system described by the equation of (70-x) B2O3-5TeO2 -20SrCO3-5ZnO -xBi2O3, x = 0, 1, 5, 10, and 15 mol. %, using the melt quenching technique at a melting temperature of 1100 ℃. The photon-shielding characteristics mainly the linear attenuation coefficient (LAC) of the prepared glass samples were evaluated using Monte Carlo (MC) simulation N-particle transport code (MCNP-5) at gamma-ray energy extended from 59 keV to 1408 keV emitted by the radioisotopes Am-241, Ba-133, Cs-137, Co-60, Na-22, and Eu-152. Furthermore, we observed that the Bi2O3 content of the glasses had a significantly stronger impact on the LAC at 59 and 356 keV. The study of the lead equivalent thickness shows that the performance of fabricated glass sample with 15 mol.% of Bi2O3 is four times less than the performance of pure lead at low gamma photon energy while it is enhanced and became two times lower the perforce of pure lead at high energy. Therefore, the fabricated glasses special sample with 15 mol.% of Bi2O3 has good shielding properties in low, intermediate, and high energy intervals.

The AC loss of 22.9kV/50MVA High-Tc Superconducting Power Cable (22.9kV/50MVA급 고온초전도 전력케이블의 교류손실)

  • Choi, Suk-Jin;Lee, Sang-Jin;Sim, Ki-Deok;Cho, Jeon-Wook;Lee, Soo-Gil;Yang, Byeong-Mo;Yoon, Hyung-Hee
    • Progress in Superconductivity and Cryogenics
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    • v.11 no.3
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    • pp.31-34
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    • 2009
  • An HTS power cable is generally composed of 2 layers for conducting and 1 layer for shielding. For the analysis of AC loss of an HTS power cable, 2-dimensional magnetic field analysis is carried out. The magnetization loss in HTS cable core was calculated, and the transport current loss was obtained from the monoblock equation and the elliptical Norris Equation. And the total AC loss of the cable was expected by the sum of magnetization loss and transport current loss. The variation of ac loss with respect to the gap and uncertain factor between the superconducting tapes was investigated, and the ac loss of 22.9kV/50MVA high-Tc superconducting power cable was calculated. These results well agree with those of experiment.