안정화된 캐시-백스터 상태를 가지는 초소수성 표면과 그 응용에 관한 연구

학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 2011.2, [ iii, 35 p. ]This work includes two separate studies regarding superhydrophobicity: 1) analytical modeling of superhydrophobic surface with inverse-trapezoidal microstructures and 2) reduction of platelet adhesion by superhydrophobic cylindrical nanoshell arrays. The abstracts of each part are as follows. Part 1. Analytical modeling of superhydrophobic surface with inverse-trapezoidal microstructures A polydimethylsiloxane (PDMS) elastomer surface with perfectly ordered microstructures having an inverse-trapezoidal cross-sectional profile (simply PDMS trapezoids) shows superhydrophobic and transparent characteristics under visible light. The addition of a fluoropolymer (Teflon) coating enhances both features and provides oleophobicity. This paper focuses on the analytical modeling of the fabricated PDMS trapezoids structure and thermodynamic analysis based on the Gibbs free energy analysis. Additionally, the wetting characteristics of the fabricated PDMS trapezoids surface before and after the application of the Teflon coating are analytically explained. The Gibbs free energy analysis reveals that, due to the Teflon coating, the Cassie-Baxter state becomes energetically more favorable than the Wenzel state and the contact angle difference between the Cassie-Baxter state and the Wenzel state decreases. These two findings support the robustness of the superhydrophobicity of the fabricated Teflon-coated PDMS trapezoids. This is then verified via the impinging test of a water droplet at a high speed. The dependencies of the design parameters in the PDMS trapezoids on the hydrophobicity are also comprehensively studied through a thermodynamic analysis. Geometrical dependency on the hydrophobicity shows that overhang microstructures do not have a significant influence on the hydrophobicity. In contrast, the intrinsic contact angle of the structural material is most important in determining the apparent contact angle. On the other hand, the experimental results showed that the...한국과학기술원 : 전기 및 전자공학과

안정화된 캐시-백스터 상태를 가지는 초소수성 표면과 그 응용에 관한 연구

학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 2011.2, [ iii, 35 p. ]This work includes two separate studies regarding superhydrophobicity: 1) analytical modeling of superhydrophobic surface with inverse-trapezoidal microstructures and 2) reduction of platelet adhesion by superhydrophobic cylindrical nanoshell arrays. The abstracts of each part are as follows. Part 1. Analytical modeling of superhydrophobic surface with inverse-trapezoidal microstructures A polydimethylsiloxane (PDMS) elastomer surface with perfectly ordered microstructures having an inverse-trapezoidal cross-sectional profile (simply PDMS trapezoids) shows superhydrophobic and transparent characteristics under visible light. The addition of a fluoropolymer (Teflon) coating enhances both features and provides oleophobicity. This paper focuses on the analytical modeling of the fabricated PDMS trapezoids structure and thermodynamic analysis based on the Gibbs free energy analysis. Additionally, the wetting characteristics of the fabricated PDMS trapezoids surface before and after the application of the Teflon coating are analytically explained. The Gibbs free energy analysis reveals that, due to the Teflon coating, the Cassie-Baxter state becomes energetically more favorable than the Wenzel state and the contact angle difference between the Cassie-Baxter state and the Wenzel state decreases. These two findings support the robustness of the superhydrophobicity of the fabricated Teflon-coated PDMS trapezoids. This is then verified via the impinging test of a water droplet at a high speed. The dependencies of the design parameters in the PDMS trapezoids on the hydrophobicity are also comprehensively studied through a thermodynamic analysis. Geometrical dependency on the hydrophobicity shows that overhang microstructures do not have a significant influence on the hydrophobicity. In contrast, the intrinsic contact angle of the structural material is most important in determining the apparent contact angle. On the other hand, the experimental results showed that the ...한국과학기술원 : 전기 및 전자공학과

트위터에서 추출된 소비자 태도 정보의 특성과 효용에 대한 연구

학위논문(석사) - 한국과학기술원 : 웹사이언스공학전공, 2013.8, [ iv, 27 p. ]Twitter is one of the most popular social media outlets available and has been expanding over the years in both scope and reach. The growing number of users, and the accessibility to their micro-posts and metadata make Twitter a popular subject for research in various research communities. In this paper, I propose and examine a content analysis method that utilizes the hierarchy of effects model, which has a very long history of use by both practitioners and academics in the field of advertising and marketing. I had judges manually annotate tweets in accordance with one of the five attitude stages the authors are assumed to be in: Atten-tion, Interest, Desire, Action, or Satisfaction. Next, I examine the tagged corpus from various aspects to iden-tify general traits and explore the possibilities for the newly gained information from the tweets. The results show that the consumer attitude information can improve the prediction quality of box-office revenues and may be used to better represent movie audience sentiment. These findings should aid other content analysis methods that utilizes Twitter by providing an additional dimension for the researchers to consider.한국과학기술원 : 웹사이언스공학전공

COATING LAYER

본 발명은 소수성, 소유성, 발수성 및 발유성을 갖는 코팅막에 관한 것이다.본 발명의 실시 예에 따른 코팅막은 기판과 상기 기판의 표면에서 바깥쪽으로 돌출된 돌출부를 포함하되, 상기 돌출부는 상기 기판의 표면과 수직한 방향으로의 단면이 역사다리꼴이고, 상기 돌출부는 상기 기판의 표면에 복수로 배열되되, 서로 인접하는 두 돌출부들은 서로 이격되도록 배열된 것을 특징으로 한다