• Title/Summary/Keyword: A357

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Effects of Melt Treatments on Microstructures and Mechanical Properties of A357 Alloy (A357합금에서 용탕처리가 미세조직 및 기계적 특성에 미치는 영향)

  • Lee, Jung-Moo;Lee, Sung-Hak;Yoon, Ji-Hyun;Kim, Kyung-Hyun
    • Journal of Korea Foundry Society
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    • v.23 no.2
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    • pp.69-76
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    • 2003
  • The present work was undertaken to investigate the mutual effect of the individual melt treatment commonly applied in aluminum foundries such as grain refining, modification, degassing and filtration on the microstructures and the mechanical properties. A357 alloys were fabricated through various melt treatments such as degassing by gas bubbling filtration, modification via the addition of Al-Sr master alloy, grain refining through the addition of Al-Ti-B master alloy and filtration before pouring of the melt. Each melt treatment was performed at its optimum condition reported in the literatures. The effects of each melt treatment and their interactions on the microstructures and mechanical properties of A357 alloy were examined.

Microstructures of Bonding Interfaces after Semi-Solid Brazing of Aluminum Using A357 as a Filler Metal (A357을 이용한 알루미늄 반응고 브레이징 접합 계면 특성)

  • Lee, S.Y.
    • Transactions of Materials Processing
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    • v.21 no.8
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    • pp.506-511
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    • 2012
  • Aluminum brazing normally requires a careful control of temperature due to the small interval between brazing and melting temperatures for base materials. Unsuitable processing conditions, including brazing temperature outside admissible range, gap between brazed materials or inadequate flux feeding, can lead to joining defects. In this study, A357 was used as a filler metal for the brazing of pure aluminum base materials and brazed at temperatures in the semi-solid state. Interface microstructures with base materials were observed using optical metallography(OM) and scanning electron microcopy(SEM) with energy dispersive spectroscopy(EDS), and compared to conventional aluminum brazing.

Lysobacter ginsengisoli sp. nov., a Novel Species Isolated from Soil in Pocheon Province, South Korea

  • Jung, Hae-Min;Ten, Leonid N.;Im, Wan-Taek;Yoo, Soon-Ae;Lee, Sung-Taik
    • Journal of Microbiology and Biotechnology
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    • v.18 no.9
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    • pp.1496-1499
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    • 2008
  • A Gram-negative, aerobic, rod-shaped, nonspore-forming bacterial strain, designated Gsoil $357^T$ was isolated from soil sample of a ginseng field in Pocheon Province (South Korea). The isolate contained Q-8 as the predominant ubiquinone and iso-$C_{16:0}$, iso-$C_{17:1}$ ${\omega}9c$, and iso-$C_{15:0}$ as the major fatty acids. The G+C content of the genomic DNA was 69.3 mol%. A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Gsoil $357^T$ was most closely related to Lysobacter gummosus (97.6%) and Lysobacter antibioticus (97.6%). However, the DNA-DNA relatedness value between strain Gsoil $357^T$ and its phylogenetically closest neighbors was less than 17%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil 357T should be classified as representing a novel species in the genus Lysobacter, for which the name Lysobacter ginsengisoli sp. novo is proposed. The type strain is Gsoil $357^T$ (=KCTC $12602^T$=DSM $18420^T$).

A357을 이용한 반응고 상태에서의 브레이징 접합면 분석

  • Choi, B.H.;Kwon, Y.H.;Lee, S.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.485-487
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    • 2008
  • Aluminum brazing needs normally careful control of temperatures due to little difference between brazing temperatures and melting temperatures of base materials. Unsuitable processing conditions such as brazing temperature, gap between brazed materials, inadequate feeding of flux, etc. can lead to occur joining defects. In this study, A357 was used as a filler metal for the brazing of pure aluminum base materials. A357 was brazed at temperatures in the semi-solid state. Interface microstructures with base materials were observed using OM and SEM/EDS and compared to conventional aluminum brazing.

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A NOTE ON MULTIPLIERS OF AC-ALGEBRAS

  • Lee, Yong Hoon
    • Journal of the Chungcheong Mathematical Society
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    • v.30 no.4
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    • pp.357-367
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    • 2017
  • In this paper, we introduce the notion of multiplier of AC-algebra and consider the properties of multipliers in AC-algebras. Also, we characterized the fixed set $Fix_d(X)$ by multipliers. Moreover, we prove that M(X), the collection of all multipliers of AC-algebras, form a semigroup under certain binary operation.