• Title/Summary/Keyword: Atomic structures

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Simulation Methods for Prediction of Membrane Protein Structure

  • Son, Hyeon-S.
    • Proceedings of the Korean Biophysical Society Conference
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    • 1998.06a
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    • pp.10-10
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    • 1998
  • IMPs are important to cells in functions such as transport, energy transduction and signalling. Three dimensional molecular structures of such proteins at atomic level are needed to understand such processes. Prediction of such structures (and functions) is necessary especially because there are only a small number of membrane protein structures determined in atomic resolution.(omitted)

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Dynamic Material Testing of Aged Concrete Cores From the Outer Wall of the High-Flux Advanced Neutron Application Reactor

  • JaeHoon Lim;Byoungsun Park;Jongmin Lim;Yun-Young Yang;Sung-Hyo Lee;Sang Soon Cho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.22 no.2
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    • pp.139-144
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    • 2024
  • Concrete structures must maintain their shielding abilities and structural integrity over extended operational periods. Despite the widespread use of dry storage systems for spent nuclear fuel, research on the properties of deteriorated concrete and their impact on structural performance remains limited. To address this significant research gap, static and dynamic material testing was conducted on concrete specimens carefully extracted from the outer wall of the High-flux Advanced Neutron Application ReactOr (HANARO), constructed approximately 30 years ago. Despite its age, the results reveal that the concrete maintains its structural integrity impressively well, with static compression tests indicating an average compressive strength exceeding the original design standards. Further dynamic property testing using advanced high-speed material test equipment supported these findings, showing the consistency of dynamic increase factors with those reported in previous studies. These results highlight the importance of monitoring and assessing concrete structures in nuclear facilities for long-term safety and reliability.

Pore size effects of adhesion and friction for nanohoneycomb structures in AFM (원자현미경에서 나노허니컴 구조물의 홀 사이즈에 따른 점착 및 마찰 거동 분석)

  • Choi, Duk-Hyun;Lee, Pyung-So;Lee, Kun-Hong;Park, Hyun-Chul;Hwang, Woon-Bong
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.129-132
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    • 2005
  • This study analyzes the behavior of adhesion and friction according to the pore size of nanohoneycomb structures in atomic force microscope (AFM). Anodic aluminum oxide (AAO) films are fabricated as nanohoneycomb structures. According to the pore diameters of the nanohoneycomb structures, the adhesive forces and the frictional coefficients arc obtained in AFM, and the behaviors are analyzed in the view of the contact area between the sphere particle and nanohoneycomb substrate. The effective Young's moduli of the nanohoneycomb structures are measured from the nanoindentation tests, and the contact areas at zero applied load are calculated by combining the porosity of the nanohoneycomb structures and the contact radius determined from JKR and DMT theory.

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A Study on the Atomic and Electronic Structures of DNA-nucleobases-adsorbed Graphene Through First-principles LCAO Method (제일원리 LCAO 방법을 이용한 DNA Nucleobase 흡착된 그라핀의 원자 및 전자구조 연구)

  • Lee, Eun-Cheol
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.6
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    • pp.510-514
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    • 2011
  • Based on first-principles LCAO method, we study the electronic and atomic structures of DNA nucleobases adenine (A), thymine (T), guanine (G), and cytosine (C) adsorbed on graphene surfaces. The ${\pi}-{\pi}$ stacking interactions between graphene and nucleobases lead to the bilayer geometries similar to the Bernal stacked graphite. Through the density of states and charge density analyses, it is found that nucleobases are physisorbed on graphene by dispersive interactions with negligible charge exchange. Our calculations reproduce the atomic structures obtained in previous plane wave calculations accurately with much less computation, and well describe the delocalized ${\pi}-{\pi}$ interactions in graphene-nucleobases system, indicating that the LCAO method is very efficient for investigating graphene-bio systems.

Assessment of Seismic Response Spatial Variation Through the Analysis of Earthquake Records at Hamaoka Nuclear Power Plant (하마오카 원자력 발전소 지진 기록 분석을 통한 지진응답의 공간적 변화 평가)

  • Ji, Hae Yeon;Ha, Jeong Gon;Kim, Min Kyu;Hahm, Dae Gi
    • Journal of the Earthquake Engineering Society of Korea
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    • v.26 no.5
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    • pp.181-190
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    • 2022
  • In assessing the seismic safety of nuclear power plants, it is essential to analyze the structures using the observed ground motion. In particular, spatial variation in which the characteristics of the ground motion record differ may occur if the location is different within the site and even if the same earthquake is experienced. This study analyzed the spatial variation characteristics of the ground motion observed at the structure and site using the earthquake records measured at the Hamaoka nuclear power plant. Even if they were located on the same floor within the same unit, there was a difference in response depending on the location. In addition, amplification was observed in Unit 5 compared to other units, which was due to the rock layer having a slower shear wave velocity than the surrounding bedrock. Significant differences were also found in the records of the structure's foundation and the free-field surface. Based on these results, the necessity of considering spatial variation in the observed records was suggested.