• 제목/요약/키워드: Park In Joon

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냉각인발된 쾌삭강의 외경선삭시 칩-공구 마찰 및 전단 특성 (Chip-Tool Friction and Shear Characteristics of Cold Drawn Free Machining Steels in Turning)

  • 이영문;조삼규;최수준;송태성;박태준
    • 한국정밀공학회지
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    • 제16권12호
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    • pp.198-203
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    • 1999
  • In this study, chip-tool friction and shear characteristics of cold drawn free machining steels in turning were assessed. To do this, a newly developed equivalent oblique cutting model was adopted. And for comparison with those of free machining steels, chip-tool friction and shear characteristics of conventional carbon steels were also investigated. The Pb-S free machining steel shows superior machinability to others. In case of the Bi-S free machining steel, the shear stress and the specific friction energy are relatively lower than those of conventional carbon steels, but its shear strain is relatively high, so it does not show any remarkable improvement of machinability.

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일반(一般)X선촬영(線撮影)에 있어서 편면(片面)시스템의 응용(應用) (An Application of Single Screen-Film System on General Radiography)

  • 박명환;조준석;송재관;허준;유장수
    • 대한방사선기술학회지:방사선기술과학
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    • 제13권2호
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    • pp.15-20
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    • 1990
  • In clinical fields, single screen-film system will be generalized according to high speed and high image qualify of intensifying screen film system in future. In single screen-film system, for imaging the best image, we must choice good film according to speed and gredient. Double screen-film system will be replaced single screen film system in general radiography. Author has thought that single screen film system will be developed new diagnosis area according to X-Ray films.

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경량 밸브 제조용 마그네슘 합금의 고온 성형 특성 (Characteristics of Hot Forming of Magnesium Alloys for Light-weight Valves)

  • 박준홍;이준호
    • 한국기계가공학회지
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    • 제11권4호
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    • pp.173-179
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    • 2012
  • In recent years, Magnesium(Mg) and its alloys have become a center of special interest in the automotive industry. Due to their high specific mechanical properties, they offer a significant weight saving potential in modern vehicle constructions. Most Mg alloys show very good machinability and processability, and even the most complicated die casting parts can be easily produced. In this study, Microstructure, Vickers hardness and tensile tests were examined and performed for each specimen to verify effects of forming conditions. Also to verify upsettability and forming limit of the specimen at room temperature and elevated temperature, upsetting experiments were performed. For comparison, experiments at elevated temperature were performed for various Mg alloy, such as AZ31, AZ91, and AM50. The experimental results were compared with those of CAE analysis to propose forming limit of Magnesium alloys.

원전구조물 부위별 철근모듈화 방안 연구 (The Rebar Modulation Method in the Area of the Nuclear Power Plant Structures)

  • 이병수;방창준;김석철;임상준;박종혁
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2013년도 추계 학술논문 발표대회
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    • pp.15-16
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    • 2013
  • Because of the complicated shape and the overcrowded arrangement of rebar, there are some problems in applying the rebar modulation for the Nuclear Power Plant Structures. In order to resolve these problems, we have been studying the rebar modulation method applying techniques of the high strength rebar for NPP Structure. After reviewing the rebar drawing of the NPP structures and performing the mock-up test, the rebar modulation method in the various area of the NPP Structure has been established. I will introduce this method and the future plan of the research.

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AC PDP의 Image Sticking 현상에 대한 기초 연구 (The Study on the image sticking phenomenon in AC PDP)

  • 함명수;이선홍;최준영;김동현;이호준;박정후
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 C
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    • pp.1677-1679
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    • 2003
  • One of the main problems in AC PDP is that the previous bright image overlaps on the new image, that is called as image sticking. In this paper, Image sticking Phenomena observed in AC PDP are defined and classified, these effects are analyzed as luminance, color purity through chromaticity diagram and firing voltage state using light waveform.

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Erysiphe quercicola Causing Powdery Mildew on Quercus rubra in Korea

  • Young-Joon Choi;Jun Hyuk Park;In-Young Choi;Lamiya Abasova;Joon-Ho Choi;HyeonDong Shin
    • 한국균학회지
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    • 제50권2호
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    • pp.137-141
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    • 2022
  • In Korea, powdery mildew has been observed on Quercus rubra, commonly called the northern red oak tree. Based on its morphological and molecular phylogenetic analyses, the fungal agent was identified as Erysiphe quercicola, but it was distinct from the other four Erysiphe species, specialized to Quercus species. This is the first confirmed report on the identity of powdery mildew found on Q. rubra in Korea. This finding can help understand the host expansion of E. quercicola and the biodiversity of powdery mildew on Quercus species.

Production and Amyloid fibril formation of tandem repeats of recombinant Yeast Prion like protein fragment

  • Kim, Yong-Ae;Park, Jae-Joon;Hwang, Jung-Hyun;Park, Tae-Joon
    • 한국자기공명학회논문지
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    • 제15권2호
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    • pp.175-186
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    • 2011
  • Amyloid fibrils have long been known to be the well known ${\alpha}$-helix to ${\beta}$-sheet transition characterizing the conversion of cellular to scrapie forms of the prion protein. A very short sequence of Yeast prion-like protein, GNNQQNY (SupN), is responsible for aggregation that induces diseases. KSI-fused tandem repeats of SupN vector are constructed and used to express SupN peptide in Escherichia coli (E.Coli). A method for a production, purification, and cleavage of tandem repeats of recombinant isotopically enriched SupN in E. coli is described. This method yields as much as 20 mg/L of isotope-enriched fusion proteins in minimal media. Synthetic SupN peptides and $^{13}C$ Gly labeled SupN peptides are studied by Congo Red staining, Birefringence and transmission electron microscopy to characterize amyloid fibril formation. To get a better understanding of aggregation-structure relationship of 7 residues of Yeast prion-like protein, the change of a conformational structure will be studied by $^{13}C$ solid-state nmr spectroscopy as powder of both amorphous and fibrillar forms.