• Title/Summary/Keyword: Boltzmann distribution

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Electromagnetic Characteristics of Dielectric Barrier Discharge Plasma Based on Fluid Dynamical Modeling (유체역학에 바탕한 플라즈마 모델링을 통한 유전체 장벽 방전 플라즈마의 전파 특성 해석)

  • Kim, Yu-Na;Oh, Il-Young;Hong, Yong-Jun;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.3
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    • pp.331-336
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    • 2013
  • In this paper, plasma modeling is achieved using fluid dynamics, thereby electron density is derived. The way proposes the key to overcoming the limitations of conventional researches which adopt simplified plasma model. The result is coupled with Maxwell-Boltzmann system in order to calculate scattering waves in various incident angle. The first part is dedicated to perform plasma modeling in dielectric barrier discharge(DBD) structure. Suzen-Huang model is adopted among various models due to the fact that it uses time independent variables to calculated potential and electron distribution in static system. The second part deals with finite difference time domain(FDTD) scheme which computes the scattered waves when the modulated Gaussian pulse is incident. Founded on it, radar cross section(RCS) is observed. Consequently, RCS is decreased by 1~2 dB with DBD plasma. The result is analogous to the RCS measurement in other researches.

Alteration of mechanical properties of tunnel structural members after a tunnel fire accident (화재 후 터널구조물 시공재료의 역학적 특성변화)

  • Chang, Soo-Ho;Choi, Soon-Wook;Kwon, Jong-Wook;Kim, Sang-Hwan;Bae, Gyu-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.9 no.2
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    • pp.157-169
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    • 2007
  • This study aimed to quantify the deterioration of tunnel structural members such as concrete lining and shotcrete lining after a tunnel fire accident by measuring their mechanical properties between $300^{\circ}C$ and $1,000^{\circ}C$. From the experiments, it was revealed that the critical temperature where mechanical properties start to decrease linearly was approximately $300^{\circ}C$. In addition, the other critical temperature where macro-cracks are induced in specimens was around $600^{\circ}C$. From a series of regression analysis, the optimum regression function with correlation coefficients over 0.99 for mechanical properties at different temperature levels was obtained as the Boltzmann function. Finally, a schematic diagram to estimate temperature distribution inside structural members as well as their mechanical properties at corresponding temperature levels quantitatively was newly proposed for RABT and RWS fire scenarios.

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