• 제목/요약/키워드: Nanostructured surface

검색결과 183건 처리시간 0.034초

High-Frequency Induction-Heated Combustion Synthesis and Consolidation of Nanostructured NbSi2 from Mechanically Activated Powders

  • Kim, Byung-Ryang;Yoon, Jin-Kook;Nam, Kee-Seok;Shon, In-Jin
    • 한국분말재료학회지
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    • 제15권4호
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    • pp.279-284
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    • 2008
  • Dense nanostructured $NbSi_2$ was synthesized by high-frequency induction-heated combustion synthesis (HFIHCS) method within 1 minute in one step from mechanically activated Nb and Si powders. Highly dense $NbSi_2$ with relative density of up to 99% was simultaneously synthesized and consolidated under the combined effects of an induced current and mechanical pressure of 60 MPa. The average grain size and mechanical properties (hardness and fracture toughness) of the compound were investigated.

High Oxygen Sensitivity of Nanocrystalline Ceria Prepared by a Thermochemical Process

  • Lee, Dong-Won;Yu, Ji-Hoon;Lim, Tae-Soo;Jang, Tae-Suk
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.416-417
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    • 2006
  • Nanostructured ceria powder was synthesized by a thermochemical process and investigated its applicability for an oxygen gas sensor. An amorphous precursor powders prepared by spray drying a cerium-nitrate solution were transformed successfully into nanostructured ceria by heat-treatment in air atmosphere. The powders were a loose agglomerated structure with extremely fine $CeO_2$ particles about 15 nm in size, resulting in a very high specific surface area $(110\;m^2/g)$. The oxygen sensitivity and the response time $t_{90}$ measured at sintered sample at $1000^{\circ}C$ was about -0.25 and very short, i.e., $3{\sim}5$ seconds, respectively.

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항균 특성을 위한 나노구조 유연 필름의 제작 및 평가 (Fabrication and Assessment of Flexible Nanostructured Film for Antibacterial Properties)

  • 박현하
    • 한국기계가공학회지
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    • 제21권5호
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    • pp.105-109
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    • 2022
  • In the field of medical and marine industries, antibacterial surfaces have been emerged as one of the most important issues. Recently, many researchers have been studying antibacterial surfaces to kill bacteria or prevent the adhesion of bacteria. In their researches, various materials and structures are suggested to inhibit the adhesion of bacteria or kill the attached bacteria. However, chemical materials such as antibiotics or metal could be toxic. Moreover, frequent use of antibiotics causes super bacteria having resistance to antibiotics. In this study, nano-pillar structured surface was fabricated using polyurethane acrylate (PUA) and the mechanically induced antibacterial function was confirmed based on the fabricated nanostructures. Nanostructures can damage the bacterial membrane of Gram-negative bacteria through stretching of bacterial membrane via interaction with the nanostructures and the bacterial membrane. Consequently, the proposed transparent, flexible and nanostructured PUA films can be one of promising candidates for antifouling and antibacterial surfaces which can be applied in various industries.

Porous Ceramic Fibers: Materials and Applications

  • 김일두
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2011년도 추계학술발표대회
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    • pp.4-4
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    • 2011
  • Extensive research efforts are directed toward the development of highly sensitive gas sensors using novel nanostructured materials. Among the different strategies for producing sensor devices based on nanosized building blocks, polymeric fiber templating approach which is combined by chemical and physical synthesis routes was attracted much attention. This unique morphology increases the surface area and reduces the interfacial area between film and substrate. Consequently, the surface activity is markedly enhanced while deleterious interfacial effects between film and substrate are significantly reduced. Both effects are highly advantageous for gas sensing applications. In this presentation, facile synthesis of hollow and porous metal oxide nanostructures and their applications in chemical sensors will be discussed.

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Cellular Adhesions and Protein Dynamics on Carbon Nanotube/Polymer composites Surfaces

  • 강민지;왕문평;임연민;김진국;강동우
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2010년도 춘계학술발표대회
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    • pp.45.2-45.2
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    • 2010
  • Possessing of carbon nanotubes in biopolymer intrigued much interest due to their mechanical and unique nanoscale surface properties. Surface stiffness can be controlled by the amount of carbon nanotubes in polymer and surface wettability can be altered by the order of nanoscale surface roughness. Protein adsorption mechanism on nanostructured carbon nanotube/polymer thin film will be discussed in this study. In addition, we identified that mechanical stimuli also contribute the messenchymal stem cell and bone cell interactions. Importantly, live cell analysis system also showed altered morphology and cellular functions. Thus, embedding of carbon nanostructures simultaneously contribute to protein adsorption and cellular interactions. In conclusion, this study demonstrated the evidence that nanoscale surface features determine the subsequent biological interactions, such as protein adsorption and cellular interactions.

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양극산화 모드 전환을 통한 기능성 알루미늄 표면 연구 (Fabrication of functional aluminum surface through anodization mode transition)

  • Park, Youngju;Jeong, Chanyoung
    • 한국표면공학회지
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    • 제55권6호
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    • pp.417-424
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    • 2022
  • This research develops an easy-to-use, environmentally friendly method for fabricating functional 1050 aluminum alloy surfaces with excellent corrosion resistance. Functional aluminum surfaces with various nanostructures are fabricated by controlling the experimental conditions of anodizing process. The experiment used a multi-step anodizing process that alternates between two different anodizing modes, mild anodizing (MA) and hard anodizing (HA), together with a pore-widening (PW) process. Among them, the nanostructured surface with a small solid fraction shows superhydrophobicity with a contact angle of more than 170° after water-repellent coating. In addition, the surface with superhydrophobicity is difficult for corrosive substances to penetrate, so the corrosion resistance is greatly improved.

Preparation of Gas Sensors with Nanostructured SnO2 Thick Films with Different Pd Doping Concetrations by an Ink Dropping Method

  • Yoon, Hee Soo;Kim, Jun Hyung;Kim, Hyun Jong;Lee, Ho Nyun;Lee, Hee Chul
    • 한국세라믹학회지
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    • 제54권3호
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    • pp.243-248
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    • 2017
  • Pd-doped $SnO_2$ thick film with a pure tetragonal phase was prepared on patterned Pt electrodes by an ink dropping method. Nanostructured $SnO_2$ powder with a diameter of 10 nm was obtained by a modified hydrazine method. Then the ink solution was fabricated by mixing water, glycerol, bicine and the Pd-doped $SnO_2$ powder. When the Pd doping concentration was increased, the grain size of the Pd-doped $SnO_2$ thick film became smaller. However, an agglomerated and extruded surface morphology was observed for the films with Pd addition over 4 wt%. The orthorhombic phase disappeared even at a low Pd doping concentration and a PdO peak was obtained for a high Pd doping concentration. The crack-free Pd-doped $SnO_2$ thick films were able to successfully fill the $30{\mu}m$ gap of the patterned Pt electrodes by the optimized ink dropping method. The prepared 3 wt% Pd-doped $SnO_2$ thick films showed monoxide gas responses ($R_{air}/R_{CO}$) of 4.0 and 35.6 for 100 and 5000 ppm, respectively.

3D 계층적 나노구조화된 표면을 갖는 소수성 유/무기 복합 필름 (Hydrophobic Organic/Inorganic Composite Films with 3D Hierarchical Nanostructured Surfaces)

  • 서희진;안진성;박준용
    • Composites Research
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    • 제34권4호
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    • pp.264-268
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    • 2021
  • 이 연구에서 우리는 3차원 계층적 나노구조화된 유/무기 복합 표면을 가진 소수성 코팅/필름을 제조하는 방법을 제안한다. 먼저 근접장 나노패터닝(PnP)이라 불리는 첨단 포토리소그래피 기술을 통해 에폭시 기반의 대면적 3차원 정렬 나노다공성 템플릿을 준비하였다. 이후, 딥 코팅을 통해 평균 직경이 22 nm인 실리카 나노입자를 템플릿에 조밀하게 함침시켜 계층적 구조화된 표면을 구현하였다. 표면에 공존하는 마이크로 및 나노 스케일 거칠기로 인해, 제조된 복합 필름은 대조군에 비해 물에 대한 높은 접촉각(>137도)을 나타내었다. 따라서 본 연구를 통해 개발된 소재 및 공정은 전통적인 코팅/필름 분야에서 다양하게 활용될 수 있을 것으로 기대된다.

Photoelectrochemical characterization of surface-modified CuInS2 nanorod arrays prepared via template-assisted growth and transfer

  • Yang, Wooseok;Kim, Jimin;Oh, Yunjung;Moon, Jooho
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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    • pp.401-401
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    • 2016
  • Although vertically aligned one-dimensional (1D) structure has been considered as efficient forms for photoelectrode, development of efficient 1D nanostructured photocathode are still required. In this sense, we recently demonstrated a simple fabrication route for CuInS2 (CIS) nanorod arrays from aqueous solution by template-assisted growth-and-transfer method and their feasibility as a photoelectrode for water splitting. In this study, we further evaluated the photoelectrochemical properties surface-modified CIS nanorod arrays. Surface modification with CdS and ZnS was performed by successive ion layer adsorption and reaction (SILAR) method, which is well known as suitable technique for conformal coating throughout nanoporous structure. With surface modification of CdS and ZnS, both photoelectrochemical performance and stability of CuInS2 nanorod arrays were improved by shifting of the flat-band potential, which was analyzed both onset potential and Mott-schottky plot.

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