• Title/Summary/Keyword: microscopic analysis

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Morphological Analysis of Fibers of the Seip Textiles through the Microscopic Examination (현미경 관찰을 통한 Seip 직물의 섬유 형태 연구)

  • 안춘순
    • Journal of the Korean Society of Costume
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    • v.21
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    • pp.87-99
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    • 1993
  • The fiber morphologies of the textiles from the burials of the Seip group of Ohio Hopewell (ca. 100 B.C. to A.D. 500)mounds were examined using light and scanning electron microscopy. A theoretical model was proposed which delineates the rate of morphological change in fibers through time and the cultural activities which occur during the life of a textile element. The Seip textiles were categorized according to their visual and structural characteristics. The microscopic examination of the Seip textiles yielded the evidence of animal hair fibers and bast fibers. The animal hair fibers of the seip textiles were identified as the hair of rabbit or hare. The bast fibers of the Seip textiles exhibited variation in morphological features such as the degree of bundle separation and the presence of transverse striations, fibrillations, or trans-verse cracks.

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Surface Heat treatment of Die material by means of CW Nd:YAG Laser (CW Nd:YAG레이저를 이용한 금형 재료의 표면열처리)

  • Yoo Young-Tae;Shin Ho-Jun;Jang Woo-Yang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.5
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    • pp.67-74
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    • 2004
  • Laser heat treatment is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power $CO_2$ lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching action to occur and the formation of matrensitic structure. In this investigation, the microstructrual features occurring in Nd:YAG laser hardening SM45C and $STD_11$ steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimisation of the processing parameters for maximum hardened depth of SM45C and $STD_11$ steel specimens of 10mm thickness by using CW:YAG laser.

Metallic pattern Heat treatment by means of CW Nd:YAG Laser (CW Nd:YAG 레이저를 이용한 금형열처리)

  • Shin, Ho-Jun;Yoo, Young-Tae;Oh, Yong-Seak;Ro, Kyoung-Bo
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1898-1904
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    • 2003
  • Laser heat treatment is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power $CO_{2}$ lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching to occur and the formation of matrensitic structure. In this investigation, the microstructrual features occurring in Nd:YAG laser hardening SM45C and $STD_{11}$ steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimisation of the processing parameters for maximum hardened depth of SM45C and $STD_{11}$ steel specimens of 10mm thickness by using CW Nd:YAG laser.

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Characteristics of Electric Signal Transmission according to Relative Amounts of Graphite in Copper-Graphite Brush (Copper-Graphite 브러시 내 흑연의 상대량에 따른 전기 신호 전달 특성에 관한 연구)

  • Park, Hyung-Kyu;Jang, Ho
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.11a
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    • pp.318-331
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    • 2000
  • Electrical and tribological behaviours of a copper-graphite brush in a slipring-brush assembly were investigated to evaluate the characteristics of electric signal transmission between a slipring and a brush. Five brush materials containing different amounts of copper and graphite were studied. The result showed that a copper-graphite brush at a particular graphite content exhibited the most stable frictional and electrical behaviour suggesting an optimum amount of a solid lubricant in a metal-graphite brush system. Microscopic observation and the surface analysis showed good agreements with this phenomena. In addition, the deviation of the friction coefficient and electric signal distortion has a close relationship with a microscopic mechanical vibration and the change of a real contact area.

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Network Modelling for Road Intersections (교차로 네트워크 모형화 방법)

  • Gang Maeng-Gyu
    • Journal of the military operations research society of Korea
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    • v.11 no.2
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    • pp.40-52
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    • 1985
  • This paper presents an algorithm to develop network models for road intersections. These models represent microscopic traffic movement in the intersections, and thus can be used to computerize the road data for a detailed analysis or simulation.

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