• Title/Summary/Keyword: shape transition

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Review of Types, Properties, and Importance of Ferrous Based Shape Memory Alloys

  • Rahman, Rana Atta Ur;Juhre, Daniel;Halle, Thorsten
    • Korean Journal of Materials Research
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    • v.28 no.7
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    • pp.381-390
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    • 2018
  • Shape memory alloys(SMAs) have revolutionized the material engineering sciences as they exhibit exclusive features i.e. shape memory effect(SME) and super-elasticity. SMAs are those alloys that when deform return to their predeformed shape upon heating, they also restore their original shape by removing the load. Research on properties of newly advent of several types of ferrous based shape memory alloys(Fe-SMAs), shows that they have immense potential to be the counterpart of Nitinol(NiTi-SMA). These Fe-SMAs have been used and found to be effective because of their low cost, high cold workability, good weldability & excellent characteristics comparing with Nitinol(high processing cost and low cold workability) SMAs. Some of the Fe-SMAs show super-elasticity. Fe-SMAs, especially Fe-Mn-Si alloys have an immense potential for civil engineering structures because of its unique properties e.g. two-way shape memory effect, super elasticity and shape memory effect as well as due to its low cost, high elastic stiffness and wide transformation hysteresis comparative to Nitinol. Further research is being conducted on SMAs to improve and impinge better attributes by improving the material compositions, quantifying the SMA phase transition temperature etc. In this research pre-existing Fe-SMAs are categorised and collected in a tabulated form. An analysis is performed that which category is mostly available. Last 50 years data of Fe-SMA publications and US Patents is collected to show its importance in terms of increasing research on such type of alloys to invent different compositions and applications. This data is analysed as per different year groups during last 50 years and it was analysed as per whether the keywords exist in title of an article or anywhere in the article. It was found that different keywords related to Fe-SMAs/categories of Fe-SMAs, almost don't exist in the title of articles. However, these keywords related to Fe-SMAs/categories of Fe-SMAs, exist inside the article but still there are not too many publications related to Fe-SMAs/categories of Fe-SMAs.

A Study on the Transition of the Perspective connected with Visual Modality (시각양식과 관련한 투시도법의 변천에 관한 연구)

  • 곽기표
    • Korean Institute of Interior Design Journal
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    • no.38
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    • pp.48-56
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    • 2003
  • This study is purposed to find the transition of the perspective connected with visual modality. The perspective based on Greek optics and euclidean geometry and rediscovered in Renaissance represents the object according to the particular moment and the point of view, is a principal fact which affect architecture, the form of a city and the spatial organization and symbolizes an ideal of the times. It embodied perception which treats the space rationally on the basis of realism and became visual modality based on the separation of the seeing subject and the world of the object. The point of view became one with the vanishing point which made up the shape and after Renaissance for four hundred years a straight line, a right angle and a circle got to be favorite geometrical choices in architecture. A fixed point of view of the subject is getting to change and break up fundamentally by the new visual technologies of the modem times.

Effects of the Myosin ATPase Inhibitor, 2,3-Butanedione-2-Monoxime, on Growth and Dimorphic Switches of Candida albicans

  • Woo, Mi-Young;Jwa, Mi-Ri;Kim, Jin-Mi;Song, Ki-Won
    • Journal of Microbiology and Biotechnology
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    • v.10 no.5
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    • pp.606-611
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    • 2000
  • Dimorphic yeast Candida albicans reversibly switches between the form of yeast and hyphae depending on external conditions. We investigated possible roles of the myosin family in the growth and dimorphic switches of C. albicans with a general myosin ATPase inhibitor, 2,3-butanedione-2-monoxime (BDM). Transition to hyphae as well as proliferation by budding was completely inhibited by BDM at 16 mM. Presence of 16 mM BDM did not affect hyphae-to-bud transition but it blocked budding. The effects of BDM on yeast growth and dimorphic switches were reversible. More than 70% of the BDM-treated cells demonstrated defects in the amount and the polarized localization of F-actin as well as in the shape and migration of the nucleus, suggesting that myosin activities are needed in these cellular processes of C. albicans.

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Quantum Spin Hall Effect And Topological Insulator

  • Lee, Ilyoung;Yu, Hwan Joo;Lee, Won Tae
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.516-520
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    • 2014
  • Fractional quantum Hall Effect (FQSH) is one of most fundamental issues in condensed matter physics, and the Topological insulator becomes its prominent applications. This article reviews the general frameworks of these development and the physical properties. FQSH states and topological insulators are supposed to be topologically invariant under the minor change of geometrical shape or internal impurities. The phase transitions involved in this phenomena are known not to be explained in terms of symmetry breaking or Landau-Ginsburg theory. The new type of phase transitions related to topological invariants has acquired new name - topological phase transition. The intuitive concepts and the other area having same type of phase transitions are discussed.

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Cu-based Bulk Amorphous Alloys in the Cu-Zr-Ti-Ni-Pd System (Cu-Zr-Ti-Ni-Pd계 비정질 벌크합금의 형성과 성질)

  • Kim, Sung-Gyoo;Bae, Cha-Hurn
    • Journal of Korea Foundry Society
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    • v.22 no.6
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    • pp.304-308
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    • 2002
  • The new Cu-Zr-Ti-Ni-Pd amorphous alloy system has been introduced and manufactured using melt-spinning and Cu-mold die casting methods. Amorphous formability, the supercooled liquid region before crystallization and mechanical properties of the alloys were examined. The reduced glass transition temperature(Trg = Tg/Tm) and the supercooled liquid region(${\Delta}$Tx = Tx-Tg) of $Cu_{49}Zr_{30}Ti_{10}Ni_5Pb_6$ alloy were 0.620 and 57 K respectively. $Cu_{49}Zr_{30}Ti_{10}Ni_5Pb_6$ amorphous alloy was produced in the rod shape with 2mm diameter using the Cu-mold die casting. The hardness value of the amorphous bulk alloy was 432 DPN.

Fabrication and Mechanical Properties of Ni-based Amorphous Bulk Alloys (Ni기 비정질 벌크합금의 제조와 기계적 성질)

  • Kim, Sung-Gyoo
    • Journal of Korea Foundry Society
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    • v.22 no.6
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    • pp.288-292
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    • 2002
  • Ni-base amorphous alloys were manufactured using melt-spinning and Cu-mold die casting methods. Amorphous formability, the supercooled liquid region before crystallization and mechanical properties were examined. The reduced glass transition temperature and the supercooled liquid region of $Ni_{51} Nb_{20} Zr_9 Ti_9 Co_8 Cu_3$alloy were 0.621 and 46 K respectively. $Ni_{51} Nb_{20} Zr_9 Ti_9 Co_8 Cu_3$ alloy was produced in the rod shape 3mm diameter using the Cu-mold die casting. Hardness, compression strength, elongation and elastic modulus of the alloy were 850 DPN, 2.75 GPa, 1.8% and 150 GPa respectively. Moreover, compression strength of 2.75 GPa was the highest value in the amorphous bulk alloy produced up to now.

Influence of particle packing on fracture properties of concrete

  • He, Huan;Stroeven, Piet;Stroeven, Martijn;Sluys, Lambertus Johannes
    • Computers and Concrete
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    • v.8 no.6
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    • pp.677-692
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    • 2011
  • Particle packing on meso-level has a significant influence on workability of fresh concrete and also on the mechanical and durability properties of the matured material. It was demonstrated earlier that shape exerts but a marginal influence on the elastic properties of concrete provided being packed to the same density, which is not necessarily the case with different types of aggregate. Hence, elastic properties of concrete can be treated as approximately structure-insensitive parameters. However, fracture behaviour can be expected structure-sensitive. This is supported by the present study based on discrete element method (DEM) simulated three-phase concrete, namely aggregate, matrix and interfacial transition zones (ITZs). Fracture properties are assessed with the aid of a finite element method (FEM) based on the damage materials model. Effects on tensile strength due to grain shape and packing density are investigated. Shape differences are shown to have only modest influence. Significant effects are exerted by packing density and physical-mechanical properties of the phases, whereby the ITZ takes up a major position.

Investigation of the superconducting properties of YBCO coated conductor based on LTSLHPM

  • Park, H.Y.;Park, S.K.;Ri, H.C.
    • Progress in Superconductivity and Cryogenics
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    • v.15 no.1
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    • pp.1-5
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    • 2013
  • We transformed the shape of a YBCO sample with striation to reduce hysteresis and ac losses. And we chose several points to analyze in detail and visualized superconducting properties like critical transition temperature, distribution of the magnetic field, distribution of the current density and hysteresis in a non-destructive manner based on Low Temperature Scanning Laser Hall Probe Microscopy (LTSLHPM) to examine the homogeneity of the sample.