• Title/Summary/Keyword: self-organized materials

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Water-Repellent Macroporous Carbon Nanotube/Elastomer Nanocomposites by Self-Organized Aqueous Droplets

  • Lim, Bo-Kyung;Lee, Sun-Hwa;Park, Ji-Sun;Kim, Sang-Ouk
    • Macromolecular Research
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    • v.17 no.9
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    • pp.666-671
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    • 2009
  • Water repellent elastomeric surfaces were fabricated successfully on SBS/MWNT nanocomposites films using the breath figure method and subsequent thermal treatment. The uniformly dispersed CNTs were found to play significant roles in tuning the size and ordering of the macroporous morphology at the nanocomposite surface as well as enhancing the mechanical properties of nanocomposites. In particular, the CNTs dispersed in a nanocomposite solution retarded the coarsening process of aqueous droplets during the breath figure process and decreased the pore size in the finally fabricated film. The water contact angle measurement showed that the double-scale structure comprised of self-organized macropores and surface the roughness induced by a thermal treatment produced a highly water-repellent nanocomposite surface.

The Development of Contents Systems on Major Course Materials for Technical College in Electric-Electronic Field (전문대학(專門大學) 전기.전자분야(電氣.電子分野) 전공교과(專攻敎科)의 컨텐츠 체제(體制) 개발(開發) 방향(方向))

  • Kim Sun-Tae;Rho Tae-Cheon;Kim Choon-Gil
    • Journal of Engineering Education Research
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    • v.5 no.2
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    • pp.22-35
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    • 2002
  • The main purpose of this study is to prepare an outline for developing the Contents Systems that achieve self-study systems to make the students adopt themselves into new study atmosphere and maximize the result of study on technical college in Electric-Electronic field. Questionnaire posed to analyze the demand of teaching materials to the students, and professors and also to find characteristics of students in technical college. The SPSSWIN/PC+ statistics Package was used to assay the collected answers. And simple frequency with percentage, average, and standard deviation were calculated to check the entire trend and actual state of each question. The primary outcomes of this study are as follows i) The students in the technical college prefer self-directed learning to lecturer-oriented teaching. ii) It is difficult to offer the technical college students normal education systems since the students?interest and motivation towards study are very low. iii) The lack of capability of foreign language and basic mathematics are considered as obstacles for many students technical college to study. iv) The professors in technical college still depend on traditional method to teach the students without organized research of the intellectual levels and attitude the students. v) Teaching materials in currently use are not appropriated to induce the motivation and interest of study from the students. Also, the teaching materials in use now were discovered not to have enough originality, practical application, andwere text based. Therefore, the improvement of the existing teaching materials was demanded while the fundamental ability to study of general students is declining. Consequently, it is necessary to introduce new teaching materials which are simple, easy, and organized to offer the studen ts study desire and interest.

Annealing Effect on controlling Self-Organized Ag/Ti Nanoparticles on 4H-SiC Substrate (4H-SiC기판 위의 자기구조화된 Ag/Ti 나노입자 제어를 위한 열처리 분석)

  • Kim, So-Mang;OH, Jong-Min;Koo, Sang-Mo
    • Journal of IKEEE
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    • v.20 no.2
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    • pp.177-180
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    • 2016
  • The effect of varying thickness of Ag/Ti metal bilayer and annealing time have investigated for controlling self-organized nanoparticles (NPs) on 4H-SiC substrate. In addition, Glass and Si substrate which have different surface energy from SiC were fabricated for analyzing interaction of agglomeration. The results of FE-SEM indicated the different formation behaviors of NPs in various ranges of fabrication condition. The surface energy was measured by using a Contact Angle Analyzer. The formation of network-like NPs was observed on Glass and 4H-SiC, respectively, whereas it was not the case on Si substrates. It has been found that the size of NPs increases with decreasing surface energy, due to particle size-dependent hydrophilic properties of substrates. The different formation behavior was explained by using Young's equation for the contact angles between the metal and different substrates.

Study on Formation of FePd Nano-dot Using Agglomeration of Fe/Au Bilayer (Fe/Au 이중층의 응집현상을 이용한 FePd 나노 점 형성에 관한 연구)

  • Koo, J.K.;Kim, J.M.;Ryua, D.H.;Choi, B.J.;Kim, D.W.;Lee, D.H.;Kim, U.I.;Mitani, S.;J.G., M. Kamiko;Ha, J.G.
    • Journal of the Korean Vacuum Society
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    • v.20 no.1
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    • pp.7-13
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    • 2011
  • [ $L1_0$ ]phase FePd nano-dot structures were successfully fabricated on self-organized Fe/Au bilayers. With atomic force microscopy, it is determined that surface morphologies of initially flat Fe/Au bilayer films were agglomerated and transformed their shape into nano-dots structures with increasing annealing temperature. With this bilayer as a template, FePd multilayers were deposited at various temperatures, i.e. $300^{\circ}C$, $350^{\circ}C$, $400^{\circ}C$, and $450^{\circ}C$. Surface morphologies of FePd superlattice had a near resemblance to self-organized bilayer. According to X-ray diffraction results, it is confirmed that $L1_0$ superlattice structures of FePd were obtained from samples which were annealed above $350^{\circ}C$. Results of X-ray photoelectron spectroscopy depth-profile analysis showed that chemical composition is identical to deposition sequence. As a result, without additional etching processes, fabrication of chemically ordered FePd superlattice nano-dots was achieved.

Self-Organized Grafting of Carbon Nanotubes by End-Functionalized Polymers

  • Lee, Sun-Hwa;Park, Ji-Sun;Koo, Chong-Min;Lim, Bo-Kyung;Kim, Sang-Ouk
    • Macromolecular Research
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    • v.16 no.3
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    • pp.261-266
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    • 2008
  • A variety of end-functionalized polymers were grafted spontaneously onto multi-walled carbon nano-tubes (MWNTs) using a solution mixing process. The end-functional groups of the polymers underwent noncovalent grafting to the defect sites at the surface of the purified MWNTs through zwitterionic interaction or hydrogen bonding. The physically grafted polymers including polystyrene (PS), poly(methyl methacrylate) (PMMA), polyethylene oxide (PEO), and polydimethylsiloxane (PDMS) provided sufficient compatibility with an organic solvent or polymer matrix, such that the nanotubes could be finely dispersed in various organic media. This approach is universally applicable to a broad range of polymer-solvent pairs, ensuring highly dispersed carbon nanotubes through simple solution mixing.

Structural Analysis of Conductive Polypyrroles Synthesized in an Ionic Liquid

  • Song, Eun-Ah;Jung, Woo-Gwang;Ihm, Dae-Woo;Kim, Jin-Yeol
    • Bulletin of the Korean Chemical Society
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    • v.30 no.5
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    • pp.1009-1011
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    • 2009
  • Nano-structured conducting polypyrroles were synthesized in the ionic liquids (ILs) based on 1-alkyl-3-methylimidazolium family with tetrachloroferrate as an anion ($C_n\;mim\;[FeCl_4]\;with\;n\;=\;4,\;8,\;and\;12$). The polypyrrole nanostructures synthesized in ILs were formed as spherical shapes. For ionic liquids with alkyl side chain length $C_4,\;C_4\;mim\;[FeCl_4]$, the size of particles was ranged around 60-nm with a relatively narrow size distribution. As the length of alkyl chain increases, the particle sizes become larger and their distributions become wider. The self-assembled local structures in the solvent ionic liquids are likely to serve as templates of highly organized nano-structured polymers. The length of the alkyl chain in ionic liquids seems to affect these local structures.

Formation of One-dimensional Nb2O5 Nanostructures by Anodization

  • Lee, Kiyoung
    • Journal of the Korean institute of surface engineering
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    • v.49 no.6
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    • pp.486-489
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    • 2016
  • In the present work, we investigate the anodization of Nb in a $K_2HPO_4$ containing glycerol electrolyte at elevated temperatures ($180^{\circ}C$). Under optimized conditions, uniformly over the entire anodized surface, self-organized porous $Nb_2O_5$ structures can be formed. The growth rate of highly ordered $Nb_2O_5$ is $1.7{\mu}m/min$ at beginning stage of anodization and the overall current efficiency is 70 %.

The Affecting Factors on Breast Self-Examination(BSE) of Korean (유방자가검진에 관한 관련요인분석)

  • Kim, Young-Im
    • Research in Community and Public Health Nursing
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    • v.14 no.3
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    • pp.496-506
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    • 2003
  • The purpose of this study is to analyze the affecting factors on breast self-examination of middle-aged women in Korea. The subjects were 141 women on Jeju Island, and materials were collected through an organized questionnaire from March to August 2002. The data were analyzed by using descriptive statistics, $x^2$-test. A-nova and Discriminant analysis by the SAS program. The major results are as follows: 1. 53% of the subjects performed the breast self-examination. The practice of breast self-examination was correlated with the education level, income, low salt diet, more than 30 minutes of regular exercise. 2. Attitudes towards breast self-examination were not a significant practice regarding breast self-examination. However, the cognition about difficulty of breast self-examination partly showed an important barrier factor to the positive attitude. 3. The average self-efficacy concerning breast self-examination was 3.03. The stages of change related to the subjects showed that a contemplation stage was high. 4. With a stepwise multiple regression, the most significant factor on self-efficacy related with breast self-examination was the contemplation stage, 30-40 aged women. high income, regular exercise, low salt diet, family cancer history, etc. 5. With the discriminant analysis, the most important factors related with the practice of the breast self-examination were income and self-efficacy. The power of discriminant was 59%. The results of this study suggests that programs should be developed to promote practice and the self-efficacy related with breast self-examination.

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Factors Affecting Early Detection Behaviors of Breast Cancer (외래내원여성의 유방암 조기검진행위에 영향을 미치는 요인)

  • Kim, Young-Im;Yang, Soo-Hyung;Jung, Hye-Sun;Lee, Chang-Hyun
    • Research in Community and Public Health Nursing
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    • v.15 no.1
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    • pp.155-164
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    • 2004
  • Purpose: The purpose of this study was to identify factors affecting early detection behaviors of breast cancer such as breast self examination(BSE), breast physical examination, mammography. Method: The subjects were 141 women on an island and materials were collected through an organized questionnaire from March, to August 2002. The data were analyzed by using descriptive statistics, $x^2$ and logistic analysis by SAS program. Results: 52.7% of the subjects performed breast self examination, 67.2% did breast physical examination and 67.7% did mammography. That is, about 60% of the subjects performed early detection behavior to find the breast cancer. Practice of breast self examination was significantly correlated with experience of physician examination and mammography. The most significant factor on BSE was a normal salted diet, and the most significant factor on physical examination and mammography was the high education level of subjects. Conclusions: According to the results of this study, it suggests that intensive education and information strategies for breast cancer early detection need to be developed. In particular, early detection programs for lower educated women should be activated.

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