• 제목/요약/키워드: Surface modification

검색결과 1,099건 처리시간 0.102초

Synthesis of Nanoparticles via Surface Modification for Electronic Applications

  • Lee, Burtrand I.;Lu, Song-Wei
    • 한국결정성장학회:학술대회논문집
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    • pp.35-58
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    • 2000
  • The demand for sub-micrometer or nanometer functional ceramic powders with a better suspension behavior in aqueous media in increasing. Redispersible barium titanate (BT) nanocrystals, green light emitting Mn2+ doped Zn$_2$SiO$_4$ and ZnS nanoparticle phosphors were synthesized by a hydrothermal method or chemical precipitation with surface modification. The nanoparticle redispersibility for BT was achieved by using a polymeric surfactant. X-ray diffraction(XRD) results indicated that the BT particles are of cubic phase with 80 nm in size. XRD results of zinc silicate phosphor indicate that seeds play an important role in enhancing the nucleation and crystallization of Zn$_2$SiO$_4$ crystals in a hydrothermal condition. This paper describes and discuss the methods of surface modification, and the resulting related properties for BT, zinc silicate and zinc sulfide.

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Surface Modification Reaction of Photocatalytic Titanium Dioxide with Triethoxysilane for Improving Dispersibility

  • Lee, Myung-Jin;Kim, Ji-Ho;Park, Young-Tae
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1275-1279
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    • 2010
  • We have carried out the surface modification of photocatalytic $TiO_2$ with triethoxysilane through dehydrogenation reaction and characterized the modified photocatalyst by spectroscopic methods, such as FT-IR, solid-state $^{29}Si$ MAS NMR, XPS, and XRF, etc. We also examined photocatalytic activity of the immobilized photocatalytic titanium dioxide with triethoxysilane by decolorization reaction of dyes such as cong red and methylene blue under visible light. Dispersion test showed that the photocatalytic titanium dioxide immobilized with triethoxysilane group has kept higher dispersibility than titanium dioxide itself. No appreciable precipitation takes place even after standing for 24 h in the 4:6 mixture ratio of ethanol and water.

박판성형을 위한 신속한 금형곡면의 수정 (Rapid Die Surface Modification for Sheet Metal Forming)

  • 유동진
    • 소성가공
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    • v.16 no.7
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    • pp.538-548
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    • 2007
  • In this paper, a novel approach which enables rapid die surface modification for sheet metal forming process is proposed. In this method an implicit surface which interpolates a given set of control points and displacement constraints is generated to compute the displacements at arbitrary points located on die surface. The proposed method does not depend on the underlying surface representation type and is affected neither by its complexity nor by its quality. In addition, the domain decomposition method is introduced in order to treat large surface model. The global domain of interest is divided into smaller domains where the problem can be solved locally. And then the local solutions are combined together to obtain a global solution. In order to verify the validity and effectiveness of the proposed method, various surface modifications are carried out fur three kinds of die surface model including polygonal surface composed of triangular and rectangular meshes, polynomial surface and NURBS surface.

Mussel-Inspired, Fast Surface Modification of Solid Substrates

  • Hong, Sang-Hyeon;Kang, Sung-Min;Lee, Hae-Shin
    • 한국진공학회:학술대회논문집
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    • pp.201-201
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    • 2011
  • Recently, mussel-inspired surface modification, called polydopamine coating has been extensively implemented to many areas, due to its material versatility and ease to use. In particular, incubation of substrates in an alkaline dopamine solution resulted in self-polymerization of dopamine and modified variety of material surfaces, including noble metals, metal oxides, ceramics, and synthetic polymers. However, the polydopamine coating has a drawback to practical use; it takes more than 12 hrs to introduce sufficient polydopamine layers to solid substrates. Here, we investigated the rate-enhanced polydopamine coating by varying reaction conditions: pH, concentration, and the addition of the oxidizing agent. As a result, the optimum condition for fast polydopamine coating was found, and solid substrates were efficiently coated with polydopamine layers in just few minutes using the condition. The polydopamine-modified surface was characterized by XPS and contact angle goniometry, and the biocompatibility of the modified surface was also proved by cell attachment test.

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Advanced LCD modes through surface modification using reactive mesogen mixed with alignment layers

  • Lee, You-Jin;Kim, Young-Ki;Jo, Soo-In;Yu, Chang-Jae;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.91-94
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    • 2009
  • We propose advanced liquid crystal display (LCD) modes through surface modification using UV curable reactive mesogen (RM) mixed with alignment layers. The LC directors on the modified alignment layer are controlled and memorized by the polymerized RMs under an applied voltage. Using the method proposed here, we can improve the response time and viewing angle characteristics through surface controlled patterned vertical alignment (SC-PVA) mode and 8-domains PVA mode, respectively. Also, we found that the method can be applicable to fabricate multi-domain structures using multiple UV exposure as same as conventional UV alignment method.

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Surface Modification of Thin Film using Trimethylchlorosilane Vaporization Treatment

  • Choo, Byoung-Kwon;Kim, Ki-Hwan;Song, Na-Young;Choi, Jung-Su;Park, Kyu-Chang;Ang, Jin;Kim, Jin-Ook;Nam, Yeon-Heui;Chae, Gi-Sung;Chung, In-Jae
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.900-903
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    • 2007
  • We introduce non-contact surface modification using trimethylchlorosilane (TMCS) for thin film transistor application. The surface is not contacted to the TMCS solution because it is vaporized at room temperature. The hydrophobic surface with contact angle $of\;{\sim}\;70^{\circ}$ can be achieved by the transfer of TMCS using a PDMS mold.

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The Effect of Surface Modification with La-M-O (M = Ni, Li) on Electrochemical Performances of Li[Ni0.8Co0.15Al0.05]O2 Cathode

  • Ryu, Jea-Hyeok;Kim, Seuk-Buom;Park, Yong-Joon
    • Bulletin of the Korean Chemical Society
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    • v.30 no.3
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    • pp.657-660
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    • 2009
  • The surface of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ cathode particle was modified by lanthanum based oxide to improve electrochemical property and thermal stability. The XRD pattern of surface layer was indexed with that of $La_4NiLiO_8$. The discharge capacity of modified electrode was higher than that of pristine sample, specially at fast charge-discharge rate and high cut-off voltage. In the DSC profile of the charged sample, the generation of heat by exothermic reaction was decreased by surface modification. Such enhancement may by attributed to the presence of stable lanthanum based oxide, which effectively suppressd the reaction between electrode and electrolyte on the surface of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ electrode.

Ethoxylated Alkylaminoanthraquinone에 의한 PET의 표면개질 - Spacer의 길이에 따른 흡착거동 - (Surface Modification of PET with Ethoxylated Alkylaminoanthraquinone - Effect of Spacer on the Adsorption Behavior -)

  • 최영주;윤남식
    • 한국염색가공학회지
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    • v.15 no.3
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    • pp.185-191
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    • 2003
  • Surface modification of poly(ethylene terephthalate) (PEI) films by treatment with ethoxylated alkylaminoanthraquinoes which was synthesized by the reaction of 1-aminoanthraquinone with poly(ethylene glycol) via a series of methylene spacer were investigated. The synthesized ethoxylated alkylaminoanthraquinones showed definite cloud point as in nonionic surfactants, and the adsorption of the compounds on PET increased near the cloud point. At same temperature the adsorption increased with the length of methylene spacer; hexyl-octyl-, and decyl-. The adsorption was limited to the extreme surface of PET film, which made the surface of PET film hydrophillic by reducing water contact angle.

표면개질에 의한 기계구조용강의 마멸특성에 관한 연구 (A Study on Wear Characteristics of Machine Structural Steel by Surface Modification)

  • 박흥식;우규성
    • Tribology and Lubricants
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    • v.22 no.2
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    • pp.73-78
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    • 2006
  • The surface modification of automobile parts is of great technological importance for the improvement of corrosion resistance, wear resistance, fatigue strength and so on. Recently, research on the development of the technology of surface modification substituting 6-balance chrome process has progressively been achieved in automobile parts. Although the innovation technology for the improvement of the corrosion-resisting and wear resistant properties through post oxidation after nitrocarburising process had attracted a great attention. For this, anodically potentiodynamic polarisation testing was carried out to corrosion resistance and friction and wear experiment according to applied load and sliding distance was carried out to evaluate the wear resistance of machine structural steel with nitrocarburising and non-nitrocarburising SM45C. The presumed wear volume was calculated with the image processing far evaluation of wear resistance of two materials. The results show that the nitrocarburising had a distinguished corrosion resistance and wear resistance than non-nitrocarburising.

실리카 에어로겔의 표면 개질 (Surface Modification of Silica Aerogels)

  • 현상훈;이찬호;김동준
    • 한국세라믹학회지
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    • v.33 no.12
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    • pp.1319-1324
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    • 1996
  • Silica aerogels were synthesis by the sol-gel-supercritical drying process using isopropanol as a solvent. Effets of the heat-treatment and the surface modification through propoxylation on the structural reinforcement as well as the surface hydrophobic/hydrophilic characteristics of aerogels were investigated. Silica aerogels synthesized by supercritical drying were hydrophobic but aerogels heat-treated above 20$0^{\circ}C$ were transformed to be hydrophilic. In particular it was found that the skeletal structure of aerogels heat-treated at 50$0^{\circ}C$ was strong enough not to crack after adsorbing a large amount of water vapor. Hydrophilic aerogels modified by propoxylation at 28$0^{\circ}C$ for 20 h were reversed to the hydrophobic form. Transition between hydrophobicity and hydrophilicity was reversible. The hydrophobicvity and the hydrophilicity of silica aerogels were attributed to the Si-Oh bond and the nonpolar C-H bond groups of orgainc species respectively.

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