• Title/Summary/Keyword: Structure Transformation

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Microstructures and Mechanical Properties of AISI 9260 Steel by Spheroidizing Heat Treatment (AISI 9260 강의 구상화 열처리에 따른 미세 조직 및 기계적 성질)

  • Joung, Rae-Un;Chung, In-Sang
    • Journal of the Korean Society for Heat Treatment
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    • v.8 no.4
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    • pp.302-317
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    • 1995
  • After initial structure of AISI 9260 steel is changed into pearlite and martensite, one is isothermally annealed at $700^{\circ}C$ below of $A_1$ transformation point and the other is isothermally annealed at the same condition after 3 cycles of heating and cooling between $680^{\circ}C$ and $780^{\circ}C$ of $A_1$ transformation point. Analyzing the changes of microstructure, mechanical properties and fractography of tension test, we obtained result as follows. The fastest spheroidization rate by changes of initial structure and heat treatment cycles is appeared at the heat treatment cycle which is isothermally annealed after 3 cycles of heating and cooling at below and above $A_1$ transformation point for martensite. At the above condition, the perfect spheroidization structure is appeared after 60hrs and after then, globular carbide is being coarsened. The mean diameter of globular carbide is $2.4{\times}10^{-3}mm$ after 90hrs. The changes of tension strength during spheroidization heat treatment follows Orwan function, ${\sigma}_o={\sigma}_i+Gb/l$, where l is interspacing of carbide particles and at the above condition, ${\sigma}_o=70.48+2.5{\times}10^{-3}/l(kg/mm^2)$. Fractography of fracture of spheroidization structure in tension test is appeared as dimple which is ductile rupture type by nucleation and growth of void, size of dimple is larger and deeper with increasing of heat treatment time.

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Bottle Label Segmentation Based on Multiple Gradient Information

  • Chen, Yanjuan;Park, Sang-Cheol;Na, In-Seop;Kim, Soo-Hyung;Lee, Myung-Eun
    • International Journal of Contents
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    • v.7 no.4
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    • pp.24-29
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    • 2011
  • In this paper, we propose a method to segment the bottle label in images taken by mobile phones using multi-gradient approaches. In order to segment the label region of interest-object, the saliency map method and Hough Transformation method are first applied to the original images to obtain the candidate region. The saliency map is used to detect the most salient area based on three kinds of features (color, orientation and illumination features). The Hough Transformation is a technique to isolated features of a particular shape within an image. Therefore, we utilize it to find the left and right border of the bottle. Next, we segment the label based on the gradient information obtained from the structure tensor method and edge method. The experimental results have shown that the proposed method is able to accurately segment the labels as the first step of product label recognition system.

A Study on Metamorphic analysis and the expressive system in Contempory Architecture (현대 건축의 메타모포시스적 해석과 표현에 관한 연구)

  • Byun, Dae-Joong
    • Korean Institute of Interior Design Journal
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    • v.20 no.1
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    • pp.14-23
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    • 2011
  • The purpose of this study is to analyse the inclinations and expressions in contemporary architecture. Specially, we call this tendency and architectural movements as architectural metamorphosis. Metamorphosis in architecture present the core of the change of Forms and spirits in a change of outward shape and terrestrial identity. As in Ovid's extended dramatic poem of change and transformation, Metamorphoses, all Souls are deathless, and migrates from one form to another. Like these stories in Metamorphoses, Ovid tells the soul never dies, but leaps one form to anther, and can take any shape. So the architectural form, transformation and deformation in contemporary architecture means architectural sensations and cognitions can even approach the soul of form and shape under the transformation. The expressions and design strategies of metamorphosis in comtemporary architecture reveal continuous and sequential formations of space, linear structure with force and vector, rhythmical wavement and folding surface, lively wiggly flows of volumns and objects, and so on. Such qualities came from the periodical needs; separation of structure and surface, poly-surfacial movement, poly-sensual expression and experience, dematerialization and the dematerialized space, formless of non-formal architecture, digital architecture. Architecture of Metamorphosis is the ways and the needs of our period to overcome the static limits prohibits the liberal thoughts, to find the ways toward the opportunities and diversities and to unlock the imaginaire of the contemporary architecture.

A study on the Structure and Transformation Rate of Heat Treatment of Forged TAP Housing and Valve for Automotive Parts (단조용 자동차 부품 T/P Housing과 Valve의 열처리에 따른 조직 및 변형 속도에 관하여)

  • 유형종;이호진;이건영;최진일
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.4 no.3
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    • pp.155-158
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    • 2003
  • The effects of Mn, V addition on the behavior of structure and the effects of cooling rate of S20C steel for use of Tn housing and valve for automotive parts have been investigated. Transformation start temperature measured from inflection point of cooling curves has been found out to decrease with increasing cooling rate and to be more sensitive to Mn contents when cooling rate is fast. It was therefore shown that the grain was refined. If there is a big compacting pressure, it is indicated that hardness becomes much greater at surface than inside.

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Transformation Behavior on Heat Treatment Condition in Grain-Refined Cu-Zn-Al Shape Memory Alloy (결정립 미세화된 Cu-Zn-Al 형상기억합금의 열처리 조건에 따른 변태거동)

  • Kang, J.W.;Jang, W.Y.;Yang, G.S.
    • Journal of the Korean Society for Heat Treatment
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    • v.4 no.4
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    • pp.34-43
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    • 1991
  • A small amount of misch metal and/or Zr was added as a dopant to 70.5wt----Cu-26wt----Zn-3.5wt----Al shape memory alloy in order to study the effect of grain refinement and heat treatments on the transformation behavior, stabilization of martensite, and shape memory ability. It was found that the addition of misch metal and Zr was very effective for reducing the grain size. The fracture mode has been changed from intergranular brittle fracture to ductile fracture with void formation and coalescence by the addition of misch metal and Zr. Aging of the ${\beta}$-phase decreases the $M_s$ temperature, but that of the martensite phase increases the $A_s$ temperature. The hysteresis of transformation temperature ${\Delta}T(A_s-M_s)$ has an increasing tendancy by grain refinement. The crystal structure of martensite was identified as monoclinic structure. As the grain size decreased, martensite stabilization more easily occured and the shape, memory ability has been reduced by the grain size refined.

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Numerical Model Experiments of Wave Transformation for the Marine Structure Design (해양구조물 설계를 위한 파랑변형 수치모형실험)

  • Jang, Ho-Sik
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.3
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    • pp.440-447
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    • 2012
  • Numerical model experiments of wave transformation due to the reclamation and the construction of breakwater in case of 50 years design wave were performed using time dependent mild slope equation included shoaling, refraction, diffraction, reflection and wave breaking. As waves propagate to the shore, wave height gradually diminishes by the bottom friction and wave breaking etc.. After the reclamation and the construction of 75 m length breakwater, wave height distributions in the lee of breakwater have the range of 29~128 cm. To make better the harbor tranquility the length of breakwater needs to extend more than 100 m. After the construction of breakwater, wave height in the lee of the structure was deduced over 80%.

Sliding Wear Characteristics of the Fe-17Mn Alloy with Various Phases (Fe-17M 합금의 상에 따른 미끄럼 마멸 거동의 변화)

  • Lee J. E.;Kim Y. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.05a
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    • pp.411-414
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    • 2005
  • It is reported that $\varepsilon$ (HCP) and $\gamma$ (FCC) phases of a Fe-17Mn alloy transform to $\alpha'$ phase, which has BCC structure, under a deformation condition. In this study, we investigated the effect of strain-induced-transformed $\alpha'$ phase on sliding wear of the Fe-17Mn alloy that originally had e and y phases. Wear tests of the materials were carried out using a pin-on-disk wear tester at various loads of 0.5N-50N under a constant sliding speed condition of 0.38m/s against glass $(83\%\;SiO_2)$ beads. The sliding distance and radius were loom and 9 mm, respectively. Wear rate of the Fe-17Mn alloy was calculated by dividing the weight loss, measured to the accuracy of $10^{-5}g$ by the measured specific gravity and sliding distance. Worn surface and wear debris of the specimens were examined using an SEM and XRD. During the wear, $\alpha'$ phase of BCC structure was formed by strain-induced transformation when the applied wear load exceeded critical values. The $\alpha'$ phase formed by the strain induced transformation increased the wear rate of the Fe-17Mn alloy.

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