• Title/Summary/Keyword: formation and stabilization

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Stabilizing Properties of SiOF Film with Low Dielectric Constant by $N_2O$ Plasma Annealing ($N_2O$ 플라즈마 열처리에 의한 저유전율 SiOF 박막의 물성 안정화)

  • Kim, Yoon-Hae;Lee, Seok-Kiu;Kim, Sun-Oo;Kim, Hyeong-Joon
    • Korean Journal of Materials Research
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    • v.8 no.4
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    • pp.317-322
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    • 1998
  • The stabilization of low dielectric constant SiOF films prepared by conventional PECVD using TEOS and $C_2F_6$ was evaluated by the $N_2O$-plasma post-deposition annealing. Properties of SiOF film became unstable when it was air-exposed or heat-treated. Water absorption of SiOF films was increased as F content was increased due to the for¬mation of F -Si- F bonds. Also F content of SiOF films decreased after heat treatment. $N_2O$-plasma post-deposition annealing was proved to be effective on stabilizing SiOF films. which was mainly due to the formation of thin SiON layer near the top surface of films. However. the value of dielectric constant was greatly increased again when $N_2O$-plasma post-deposition annealing was done for a long time. To stabilize the SiOF films without an increase of dielec¬tric constant by $N_2O$- plasma post-deposition annealing. the annealing time should be kept the minimum value. to which stabilizing effects against air environment and heat treatment were preserved.

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Thermotropic Liquid Crystalline Behavior of Poly[1-{4-(4'-nitrophenylazo)phenoxycarbonylalkanoyloxy}ethylene]s (폴리[1-{4-(4'-니트로페닐아조)페녹시카보닐알카노일옥시}에틸렌]들의 열방성 액정 거동)

  • Jeong, Seung-Yong;Ma, Yung-Dae
    • Polymer(Korea)
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    • v.32 no.5
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    • pp.489-496
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    • 2008
  • The thermotropic liquid crystalline behavior of a homologous series of poly[1-{4-(4' nitrophenylazo) phenoxycarbonylalkanoyloxy}ethylene]s (NAPEn, n = $2{\sim}8$,10, the number of methylene units in the spacer) have been investigated. All of the homologues formed monotropic nematic phases. The glass transition temperatures decreased with n. This is attributed to a plasticization of the backbone by the side chains. The isotropic-nematic phase transition temperatures decreased with increasing n up to 7 and showed the odd-even effect. However it became almost constant when n is more than 7. This behavior was rationalized in terms of the change in the average shape of the side chain on varing the parity of the spacer. This rationalization also accounts for the observed variation of the entropic gain for the clearing transition. The mesophase properties of NAPEn were entirely different from those reported for the polymers in which the azobenzene groups are attached to polyacrylate, polymathacrylate, and polystyrene backbones through polymethylene spacers. The results indicate that the mode of chemical linkage of the side group with the main chain plays an important role in the formation, stabilization, and type of mesophase.

The Origin and Formation of Korean Public Art Theories in the 1980s (1980년대 민중미술론의 기원과 형성)

  • Choi, Youl
    • The Journal of Art Theory & Practice
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    • no.7
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    • pp.37-64
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    • 2009
  • The theories of Korean Public Art originated by the artists who were against dictatorship and they associated with democratic politicians. They criticized the Fine art that were supported by the dictatorship and gave their efforts for restoration of 'resistance paintings(against dictatorship)', 'proletarian painting', 'realism painting'. In addition, they participated new social ideology(democracy) movement and demonstrated for their rights in arts. These became the main kernel the public art theory was initiated. The public artists splitted into several different parts and participated in the democratic social movement as well as the art movement for freedom. They opened various art exhibitions within different genre, diverse space for various art section such as an exhibition hall, a factories, a university, or a congregation square. Furthermore, the public art theorists published their divergent views through newspaper/broadcasting or unauthorized printed materials. Most of the public artist and the theorists kept their relationship strongly until 1985, the time when 'National Arts Association' started. In 1983 and 1984, they were clearly separated into two parts; artists(move only in art museums) and activists(move in public spaces like school, convention square etc). Their ideological separation also took out national problems. The division; professional artists and armatures, became the social issue as a social stratification matter. And in creating method, there are also other conflicts; critical realism, and public realism as well as western painting and traditional one. These kinds of separation and conflicts made different Public artists associations, under divergent names; 'Reality and Speak'(R&S), 'KwangJu Art Association', 'Durung', 'Dang(Land)', and 'Local Youth Students Association'. In addition, their ideology and pursuit toward art movements were very difference. However, the differences and conflicts weakened When the oppression of democratic education from new dictatorship(Pres. Jun, Doo Hwan) came out. In August. 1985 the government opened to the public so called, 'The draft of School stabilization law'(Hankwon Anjung Bup) to control the teachers' rights and that initiated bigger street demonstration and conflicts between police and educators. In November.1985, assembly meeting of National Arts Association in democracy opened as 'ONE' combined organization. In this presentation, I'd like to summarize the stream of art movement until 1984, and clarify the main art theories that lead the Public Art Movements in 1980s. The main theories in 1980s are crucial because they become the origin of public art theories. This presentation started with O,youn's "Hyunsil Dong In the first declaration" and explained the absent of practice in 1970s. In addition, Won, Dong Suk 's theory was mentioned as all over struggles in theories before 1980s. GA and R&S 's founding declarations in 1970s were the start of public art theorists' activities and this article reported the activities after the declarations. First, realism base on the consciousness of reality. Second, practice art democratization based on the ideology. Third, the subject of public art movement based on understanding people's social stratification structure. Fourth, the matters of national forms and creative ways in arts based on showing reality. Fifth, the strong points in arts that the practitioners accepted. About the public art theories around 1984, I discussed the dividing point of public art theories that were shown in 'generation theory', 'organization theory', and 'popularization theory' by the practitioners. The public realism theory that subjects the contradiction of reality and point out the limits of critical realism not only showing the new creative ways but also giving the feeling of solidarity to the public art activist groups. After that, public art movements expressed 'Dismentlement of Capitalism' and 'Public revolution'. In addition, the direction of public art movements were established strongly. There were various opinions and views during the start and formation of the public art theories. The foundation of theorists activities derived from the practitioners who had the concept based on stratification and nationalism. The strong trend of group division spreaded out by practitioners who opened art work together in factories, universities, squares and rural areas. Now many lively active practitioners are gone to the other field not related with arts, and others join into professional art field not public art one with unknown reason. The theorists have the same situation with the practitioners. It means to me that theory always have to be based on the practice.

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A Conversion of AFm Phases by Addition of CaCO3, CaCl2 and CaSO4 · 2H2O (CaCO3, CaCl2 및 CaSO4 · 2H2O 첨가에 의한 AFm상의 변화)

  • 이종규;추용식
    • Journal of the Korean Ceramic Society
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    • v.40 no.1
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    • pp.24-30
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    • 2003
  • A formation and conversion of AFm phases decisively play role in the hydration, hardening and corrosion processes of various cement. In this study, the conversion of Alumino-Ferrite Monohydrates(AFm) phases under the addition of $CaCO_3,;CaCl_2;and;CaSO_4{cdot}2H_2O$was investigated by the XRD quantitative analysis. The thypical AFm phases are $M_S(monosulfoaluminate),;M_C(monocarboaluminate);and;M_{Cl}(monochloroaluminate and also Called Friedel's salts)$in this cementitious system, The conversion reaction were not occurred in $M_C-CaCO_3,;M_{Cl}-CaCO_3$ and $M_{Cl}-CaCl_2$system. However, in $M_S-CaCO_3$ system, ettringite and $monocarboaluminate(M_C)$ were formed. In $M_S-CaCl_2;system;M_S$ was transformed to Friedel's $salts(M_{Cl})$ and ettringite was formed. In the case of $CaSO_4{cdot}2H_2O$ addition, all AFm $phases(M_S,;M_C;and;M_{Cl})$ were transformed to ettringite. The order of stabilization of AFm phases under $CaCO_3,;CaCl_2;and;CaSO_4{cdot}2H_2O$ was as follows : $M_S< M_C