• Title/Summary/Keyword: Back scattered electron

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Description of the phytoliths of the genus Oryza, with a key to species (벼속(Oryza) 식물규소체 검색표와 기재)

  • Whang, Sung Soo
    • Korean Journal of Plant Taxonomy
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    • v.39 no.3
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    • pp.199-215
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    • 2009
  • Phytoliths formed on the leaf-blades of the seventeen Oryza species were examined using back-scattered electron imaging. The resulting descriptions of the phytoliths became the basis for a new key to the species of the genus. This key includes features useful for specific identification related to the silica bodies originating from epidermal cells upon both the mid-vein and bulliform cell, as well as of phytoliths originating from papillae, prickle hairs, large and small trichomes, and stomatal apparatus. These detailed phytolith descriptions, back-scattered electron images, and keys to both adaxial and abaxial sides of leaves, can now be used in identifying phytoliths from archaeological samples as well as extant species of Oryza.

Design and Manufacture of an Electron Detector for Scanning Electron Microscope (주사전자현미경용 전자검출기의 설계 및 제작)

  • Jeon, Jong-Up;Kim, Ji-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.4
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    • pp.53-60
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    • 2008
  • Electron detectors used in scanning electron microscope accept electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. Electron detector is one of the key components dominating the performance of scanning electron microscope so that the development of electron detectors having high performance is indispensable to acquire high quality images using scanning electron microscope. In this paper, we designed and manufactured an electron detector and conducted a couple of image capture experiments using it. In particular, scintillator which generates light photons when it is struck by high-energy electrons was manufactured and experimental studies on the optimization of manufacturing condition was carried out. From experiments to evaluate the performance of our detector, it was verified that the performance of our detector is equivalent to or better than that of the conventional one.

2-D & 3-D Observations on the microstructures of Super Bainitie TRIP Steels using Total Analysis System (TAS (Total Analysis System)를 이용한 SB-TRIP강에서의 2-D & 3-D 미세구조 분석 연구)

  • Seol, J.B.;Lim, Y.R.;Park, C.G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.10a
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    • pp.209-212
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    • 2009
  • It has been widely reported that carbide-free bainitic steels or super-bainite WP (SB-TRIP) steels for the automotive industry are a new family of steels offering a unique combination of high strength and ductility. Hence, it is important to exactly evaluate the volume fraction of RA and to identify the 3-D morphology of constituent phases, because it plays a crucial role in mechanical properties. Recently, as electron back-scattered diffraction (EBSD) equipped with focused ion beam (FIB) has been developed, 3-D EBSD technique for materials science are used to these steels. Moreover, newly developed atom probe tomography (APT) technique can provide the exact distribution and chemical concentration of alloying elements in a sub-nm scale. The APT analysis results indicate exactly the distribution and composition of alloying elements in the austenite and bainite phases of SB-TRIP steels with the atomic-scale resolution. And thus, no partitioning of aluminum and manganese atoms was showed between the austenite containing $7.73{\pm}0.39$ at% C and the bainitic ferrite associated with $0.22{\pm}0.06$ at% C in the SB-TRIP steel.

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2-D & 3-D Observations on the Microstructure of Super Bainite TRIP Steels using Total Analysis System (TAS(Total Analysis System)을 이용한 SB-TRIP강에서의 2-D & 3-D 미세구조 분석 연구)

  • Seol, J.B.;Lee, B.H.;Park, C.G.
    • Transactions of Materials Processing
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    • v.19 no.1
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    • pp.44-49
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    • 2010
  • It has been widely reported that carbide-free bainitic steels or super-bainite TRIP (SB-TRIP) steels for the automotive industry are a new family of steels offering a unique combination of high strength and ductility. Hence, it is important to exactly evaluate the volume fraction of RA and to identify the 3-D morphology of constituent phases, because it plays a crucial role in mechanical properties. Recently, as electron back-scattered diffraction (EBSD) equipped with focused ion beam (FIB) has been developed, 3-D EBSD technique for materials science are used to these steels. Moreover, newly developed atom probe tomography (APT) technique can provide the exact distribution and chemical concentration of alloying elements in a sub-nm scale. The APT analysis results indicate exactly the distribution and composition of alloying elements in the austenite and bainite phases of SB-TRIP steels with the atomic-scale resolution. And thus, no partitioning of aluminum and manganese atoms was showed between the austenite containing $7.73{\pm}0.39$ at% C and the bainitic ferrite associated with $0.22{\pm}0.06$ at% C in SB-TRIP steel.

Focused ion beam-scanning electron microscope examination of high burn-up UO2 in the center of a pellet

  • Noirot, J.;Zacharie-Aubrun, I.;Blay, T.
    • Nuclear Engineering and Technology
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    • v.50 no.2
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    • pp.259-267
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    • 2018
  • Focused ion beam-scanning electron microscope and electron backscattered diffraction examinations were conducted in the center of a $73\;GWd/t_U\;UO_2$ fuel. They showed the formation of subdomains within the initial grains. The local crystal orientations in these domains were close to that of the original grain. Most of the fission gas bubbles were located on the boundaries. Their shapes were far from spherical and far from lenticular. No interlinked bubble network was found. These observations shed light on previous unexplained observations. They plead for a revision of the classical description of fission gas release mechanisms for the center of high burn-up $UO_2$. Yet, complementary detailed observations are needed to better understand the mechanisms involved.

Sintering Characteristics of ZnO Fabricated by Spark Plasma Sintering Process for High Temperature Thermoelectric Materials Application (고온용 ZnO계 열전 재료의 방전플라즈마 소결 특성 및 미세구조)

  • 심광보;김경훈;홍영호;채재홍
    • Journal of the Korean Ceramic Society
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    • v.40 no.6
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    • pp.560-565
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    • 2003
  • M-doped (M=Al, Ni) ZnO thermoelectric materials were fully densified at low temperatures of 800∼1,000$^{\circ}C$ and their sintering characteristics and microstructural features were investigated. Electron microscopic analysis showed that the addition of NiO promoted tile formation of solid solution and caused actively grain growth. The addition of A1$_2$O$_3$ prevented the evaporation of pure ZnO at grain boundaries and suppressed the grain growth by the formation of secondary phase. In case of the addition of A1$_2$O$_3$ together with NiO, the specimen showed an excellent microstructure and also the SEM-EBSP (Electron Back-scattered Diffraction Pattern) analysis confirmed that it shows a superior grain boundary distribution to the others specimens. These microstructural characteristics induced by the addition of A1$_2$O$_3$ together with NiO may increase the electrical conductivity by the increase in carrier concentration and decrease the thermal conductivity by the phonon scattering effect and, consequently, improve the thermoelectric property.

Oscillatory Zoning in Alunite from the Sungsan Mine, Korea (해남 성산광산의 명반석 내 진동누대구조에 관한 연구)

  • Cho, Hyen-Goo;Kim, Soo-Jin
    • Journal of the Mineralogical Society of Korea
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    • v.5 no.1
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    • pp.42-47
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    • 1992
  • The oscillatory zoning pattern in alunite from the Sungsan mine, Korea was studied by the back-scattered electorn(BSE) imaging and electron microprobe analysis. This zoning is not visible under the polarizing microscope, but is spectacularly illustrated in BSE image. Electron microprobe analysis reveals that the zoning is substantially due to the variation in the content of Na substituting for K in the A site of the alunite structure. With increasing brightess in BSE image, conternt of K increases but that of Na decreases. Delicate fine-scale zoning and sharp boundaries between adjacent zones suggest that the zoning would be ascribed to the variation in the composition of hydrothermal fluid around the growing alunite crystals. The effective factors for such a variation would be 1) the fluctuation in the composition of entering fluid. and/or 2) the rapid change in composition of fluid due to the rapid precipitation of more stable. Na-poor alunite.

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Textures of Claystones and Their Genetic Significances in the Cheonunsan Formation of the Hwasoon Area (화순지역 천운산층 중의 점토암의 조직과 그 성인적 의미)

  • 김수진;추창호;이동진
    • Journal of the Mineralogical Society of Korea
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    • v.11 no.1
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    • pp.13-19
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    • 1998
  • Textures of claystones of the Cheonunsan Formation in the Hwasoon area have been studied using optical microscope and electron microprobe. Microscopic images were observed under the optical microscope using the transmitted polarizing light from thin sections and under the electron microprobe using the back-scattered electron beam from the polished sections. Identification of minerals were made using X-ray diffraction analysis and chemical analysis by electon microprobe. Textural analyses show that the original sedimentary claystones rich in aluminium were subjected to metamorphism by which they changed to the metamorphosed claystone consisting mainly of chloritoid, quartz, andalusite and illite. Later intensive hydrothermal kaolinization of this metamorhosed claystones resulted in the formation of high-aluminous claystones rich in kaolinite exhibiting various complicated replacement textures.

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