• Title/Summary/Keyword: 원통형 껍질

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Acoustic Identification of Inner Materials in a Single-layer Cylindrical Shell with Resonance Scattering Theory (공명 산란 이론을 이용한 단일층 원통형 껍질 내부 물질의 음향 식별)

  • Jo, Young-Tae;Kim, Wan-Gu;Yoon, Suk Wang
    • The Journal of the Acoustical Society of Korea
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    • v.34 no.4
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    • pp.257-263
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    • 2015
  • Acoustic identification of inner materials in a single-layer cylindrical shell is investigated with acoustic resonance theory. The theoretical resonance peak frequencies for a cylindrical shell are little affected by the density variation, but remarkably changed by the sound speed variation of inner materials. Such acoustic dependency can be utilized to identify inner materials in a cylindrical shell. Acoustic resonance spectrogram for a single-layer cylindrical shell is theoretically plotted as functions of normalized frequency and sound speed of inner materials. The inner materials can be acoustically identified by overlapping acoustic resonance peaks from measured backscattering sound field on the spectrogram. To experimentally confirm this method, backscattering sound field of cylindrical shell filled with water, oil or ethylene glycol was measured in water tank. The inner materials could be identified by acoustic resonance peaks of the backscattering sound field monostatically measured with a transduce of 1.05 MHz center frequency.

A study on structural properties of copper nanowires (구리 나노와이어의 구조적 특성에 관한 연구)

  • 강정원;권오근;황호정
    • Journal of the Korean Vacuum Society
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    • v.11 no.1
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    • pp.59-67
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    • 2002
  • The structures and properties of Cu nanowires have been investigated using molecular dynamics simulations. Cylindrical multi-shell Cu nanowires maintain their structures at room temperature and their structural properties are different from the structural properties of nanowires with face-centered-cubic structure. The results from nanopillar and tensile testing of cylindrical multi-shell Cu nanowire showed structures related to pentagonal needle-like crystal structures. Since the subunits of pentagonal nanowire with needle-like crystal are face-centered-cubic structure, pentagonal multi-shell nanowires are stable one-dimensional structures in nanostructured materials.

A New Mini Kiwifruit Cultivar, "Green King" (다래 신품종 "그린킹")

  • Kim, Chun-Hwan;Kim, Seong-Cheol;Song, Eun-Young;Ro, Na Young;Kim, Misun;Moon, Doo-Young;Kang, Kyung Hee;Jang, Ki-Chang
    • Korean Journal of Breeding Science
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    • v.40 no.4
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    • pp.461-465
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    • 2008
  • "Green King" is a new mini kiwifruit variety developed at the National Institute of Subtropical Agriculture (NISA), RDA in 2005, which was an edible fruit without peeling. This variety was selected from seeds obtained from the cross breeding between Actinidia chinensis cv. "Apple Sensation" and A. arguta in 1998. Seedling and line selections were conducted from 1999 to 2002, and characteristic trials were carried out from 2003 to 2004. The branch of "Green King" sprouts strongly and the color of leaf is slightly dark green. The shape of fruit is cylindric and the color of peel is green or yellowish green without hair. The average weight of fruit is 15.9 g. The core is small and soft, the pericarp is light green. Soluble solids concentration is $15.4^{\circ}Brix$. The fruit is sweet with slightly acid taste, containing total acid 1.3%, and the yield is higher over twice than that of A. arguta. The content of vitamin C is higher than that of A. arguta. The harvesting time is from middle October. This variety can be planted in the central and southern region of Korea.