• Title/Summary/Keyword: morphology formation

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Analysis of Traditional Urban Morphology of Korean Contemporary City and Institutional Measures for Preservation

  • Choi, Min-Ah
    • KIEAE Journal
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    • v.14 no.2
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    • pp.47-59
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    • 2014
  • In the present circumstance of exploring measures for sustainable development, finding and using planning elements of historical city is getting important as a urban planning tool. Thus this study aims to examine the characters of Korean traditional urban form through three periods, Josun, modern and contemporary eras. Three urban centers representing different characteristics were selected; historical center based on 14th century's traditional planning, modern period urban center, which is related with development of railway, and contemporary urban center of late 20th century. Analyse of urban tissue, composed with form and scale of street network, blocks and plots, shows that each urban center of Seoul has certain common attributes in terms of morphology in spite of the difference of formation and development period. However this historical urban forms are rarely applicated in the current urban planning, such as new-town planning or district unit plan. This shows the necessity of modification of urban regulation for preserving the identity of our city and pursuing sustainable development.

Evolution of phase morphology and in-situ compatibilization of polymer blends during ultrasound-assisted melt mixing

  • Kim, Hyungsu;Ryu, Joung-Gul;Lee, Jae-Wook
    • Korea-Australia Rheology Journal
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    • v.14 no.3
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    • pp.121-128
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    • 2002
  • A series of thermoplastic polymers and their blends were melt-processed with high intensity ultrasonic wave in an intensive mixer. For the effective transfer of ultrasonic energy, an experimental apparatus was specially designed so that polymer melt can directly contact with ultrasonic horn. It was observed that significant variations in the rheological properties of polymers occur due to the unique action of ultrasonic wave without any aid of chemical additives. It was also found that the direct sonication on immiscible polymer blends in melt state reduces the domain sizes considerably and stabilizes the phase morphology of the blends. The degree of compatibilization was strongly affected by viscosity ratio of the components and the morphology was stable after annealing in properly compatibilized blends. It is suggested that ultrasound assisted melt mixing can lead to in-situ copolymer formation between the components and consequently provide an effective route to compatibilize immiscible polymer blends.

Development and Morphology of pelvetia siliquosa Tseng et Chang (Phaeophyta) In Culture

  • Yoon, Jang-Taek;Gong, Young-Gun;Chung, Gyu-Hwa
    • Journal of Aquaculture
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    • v.16 no.1
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    • pp.37-43
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    • 2003
  • The present study reports morphology and developmental pattern off siliquosa cultured in a laboratory condition. The zygote was spherical with a diameter of 85 ${\mu}{\textrm}{m}$. During development the polarized zygote divided horizontally and the lower daughter cell divided horizontally into 2 cells. The upper cell was divided repeatedly in horizontal and vertical directions to form a cylinder-like structure, which subsequently developed into secondary and tertiary dichotomous branches. Optimum temperature for zygote release and fertilization was 25C. Injury inflicted by slicing was cured by epidermal differentiation, and adventitious branches; the branches emerging from the pith cells, however, developed no rhizoid. Adventitious branch formation rate was over 88% in all plates supplemented with 0.5 mg/L IAA and peaked at 98% under 0.5 mg/L IAA plus 0.5-5.0 mg/L NAA treatment. NAA stimulated the differentiation of adventitious branches at a wide range of concentrations, while IAA, 2,4-D and kinetin exhibited dose-dependent stimulation.

Carbon Nanofibers with Controlled Size and Morphology Synthesized with Ni-MgO Catalyst Treated by Mechanochemical Process

  • Fangli Yuan;Ryu, Ho-Jin;Kang, Yong-Ku;Park, Soo-Jin;Lee, Jae-Rock
    • Journal of the Semiconductor & Display Technology
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    • v.3 no.1
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    • pp.9-13
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    • 2004
  • Carbon nanofibers (CNFs) with uniform diameter and controlled size were prepared from catalytic decomposition of $\textrm{C}_{2}\textrm{H}_{2}$ with Ni-MgO catalyst treated by mechanochemical (MC) process. The properties of Ni catalyst, such as size, distribution and morphology, can be governed by tuning grinding time in MC process. As a result, size and structure of CNFs can be tailored. The effect of grinding time to the as-grown CNFs was studied. CNFs with diameter from 10-70 nm were synthesized. CNFs with bundle formation sharing one tip and twisted CNFs were also synthesized with catalyst treated by MC process.

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Effects of structure and morphology of anodized Al thin film on magnetic properties (알루미늄 양극산화 피막의 구조 및 형상이 자기적 특성에 미치는 영향)

  • 권용덕;박용수
    • Journal of the Korean institute of surface engineering
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    • v.26 no.2
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    • pp.45-54
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    • 1993
  • In this study, magnetic properties of anodized Al film deposited with ferro-magnetic metals in the capacity of perpendicular magnetic recording media were measured and evaluated to find out the role of structure and morphology of the oxide films on magnetic characteristics. The object of this work was to present the conditions of magnetic thin film formation with more superior magnetic property. Anodizing was carried out under various conditions, and then the anodized film were electro-deposited with Co, Ni, Fe and their alloys. Coercive force and residual magnetization in perpendicular direction increased as the pore length of anodized film increased. It was attributed to the increase of the amount of depoisted metals and the ratio of length/diameter of pores. Morphology of anodized films in phosperic acid was not similar to that of sulfuric acid, and thin films in the former solution had perpendcular magnetic anisostropy because of large diameter, irregular length and distribution of the pores. It was found that magnetic properties of the thin films, which had doubled layer of two metals, were dominated by the metal electrodeposited on the surface of the anodized oxide films.

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Morphology Observation of Nanostructured Ti-25Ta-xZr Alloys

  • Kim, Hyun-ju;Ko, Yeong-Mu;Choe, Han-Cheol
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2012.05a
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    • pp.331-331
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    • 2012
  • In this study, we investigated morphology observation of nanostructured Ti-25Ta-xZr alloys. Ti-25Ta-(3wt%~15 wt%) Zr alloys were prepared by a vacuum arc-melting furnace. Formation of nanotubular structure was achieved by an electrochemical method in 1M $H_3PO_4$ electrolytes containing 0.8%wt.% NaF. Nanotube morphology depended on alloying elements.

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Does the SED of a galaxy constrain its merger history?

  • Lee, Jae-Hyun;Yi, Suk-Young
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.76.2-76.2
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    • 2011
  • It is widely accepted that the SED of a galaxy relates to its morphology. In addition, the SED of the galaxy is closely connected to its star formation history, and its morphological properties are affected by the merger history, interactions with its environment, and the gravitational instability of its dynamical system. Thus, it is likely that star formation history correlates to the elements that determine morphological properties. Among the elements, this study investigates how much the merger histories of galaxies influence their star formation histories. By using simple merger trees and semi-analytic models, which disregard feedback processes to exclusively identify merger effects on star formation histories, we examine the relation between various merger histories and SEDs of galaxies. From the results, we discuss whether the SED of a galaxy can represent and constrain its merger history.

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A study of a tidally interacting BCD pair, ESO 435-IG20 and ESO 435-IG16

  • Kim, Jinhyub;Sung, Eon-Chang;Chung, Aeree
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.44.1-44.1
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    • 2014
  • Blue Compact Dwarf galaxies (BCDs) are systems that recently have experienced the burst of star formation. As one of the causes for active star formation in BCDs, tidal interaction (fly-by or merger) has been suggested. A pair of BCDs, ESO 435-IG20 and ESO 435-IG16 are separated by only ~80 kpc in projection at a similar redshift (at a ~9 Mpc distance), and hence suspected to be a good example of such case. Intergalactic atomic hydrogen gas found in HIPASS survey is also suggestive of this hypothesis. In this study, we probe the HI morphology and kinematics of this BCD pair using ATCA HI data to study detailed interaction history. We investigate various star formation tracers of the pair to study how responsible tidal interaction is for triggering star formation in these galaxies.

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Analysis of nano-cluster formation in the PECVD process

  • Yun, Yongsup
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.2
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    • pp.144-148
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    • 2013
  • In this paper, the ultra water-repellent thin films were prepared by RF PECVD. On the basis of surface morphology, chemical bonding states and plasma diagnostics, a formation model of clusters for the ultra water-repellent films was discussed from considerations of formation process and laser scattering results. Moreover, using laser scattering method, the relative change of quantity of nano-clusters or size of agglomerates could be confirmed. From the results, the films were deposited with nano-clusters and those of agglomerates, which formed in organosilicon plasma, and formation of agglomerates were depended on the deposition time.

Study of Morphology and Physical Properties of Indian Mallow(Abutilon avicennae Gaertner) Fibers by Image Analyzer (화상분석기를 이용한 어저귀 섬유의 형태학적 특성과 물성연구)

  • 정선화;조남석
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.35 no.4
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    • pp.17-22
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    • 2003
  • A kind of image analysis system is used to investigate the structural features of the papers made from Indian mallow. The screen mark on the paper was identified and analyzed. The dusts, shives and fiber bundles were manifested and calculated. In the aspect of Indian mallow hanji's surface characteristics analyzed by an Image analyzer, the average of gray level and its standard deviation hanji from the woody core were rather lower than of bast fiber pulp because of better sheet formation of the formers. Hower. high brightness hanji showed high value of gray level. The sheet formation and paper opacity were increased with the decrease of standard deviation of gray level. From these results, gray level measurement could be used to predict the paper opacity as well as sheet formation.