• 제목/요약/키워드: Nanopowder

검색결과 229건 처리시간 0.027초

염기성 촉매제를 이용한 염료감응 태양전지의 효율에 관한 연구 (A Study on the Efficiency of Dye Sensitized Solar Cell Employing TiO2 Photoelectrode Synthesized Using Basic Catalyst)

  • 기현철;정행윤;구할본
    • 한국전기전자재료학회논문지
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    • 제26권10호
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    • pp.736-740
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    • 2013
  • In this study, the influence of electrochemical properties by mixing Tetrabutylammonium hydroxide (TBAOH) and ammonium hydroxide (NH4OH) electrode on the dssc. The titanias were prepared using a sol-gel method by mixing Tetrabutylammonium hydroxide and Ammonium hydroxide. The $TiO_2$ nanopowder prepared by sol-gel methode, and to improve the distributed properties of $TiO_2$ nanopowder, the TBAOH and NH4OH was added. The I-V values of cells show that the Tetrabutylammonium has 6.51% efficiency.

탄소나노튜브의 중저온에서의 화학적 합성 (Synthesis of Carbon Nanotubes by Chemical Method at Warm Temperatures)

  • 안중호;이상현;김용진;정형식
    • 한국분말재료학회지
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    • 제13권5호
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    • pp.305-312
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    • 2006
  • Amorphous carbon nanotubes were synthesized by a reaction of benzene, ferrocene and Na mixture in a small autoclave at temperatures as low as $400^{\circ}C$. The resulting carbon nanotubes were short and straight, but their inner hole was filled with residual products. The addition of quartz to the reacting mixture considerably promoted the formation of carbon nanotubes. A careful examination of powder structure suggested that the nanotubes in this process were mainly formed by surface diffusion of carbon atoms at the surface of solid catalytic particles, not by VLS(vapor-liquid-solid) mechanism.

The Effect of Pre-compaction on Density and Mechanical Properties of Magnetic Pulsed and Sintered $Al_2O_3$ Bulk

  • Hong, S.J.;Lee, J.K.;Lee, M.K.;Kim, W.W.;Rhee, C.K.
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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    • pp.967-968
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    • 2006
  • This research reports for the successful consolidation of $Al_2O_3$ powder with retained ultra-fine structure using MPC and sintering. Measurements in the consolidated $Al_2O_3$ bulk indicated that hardness, fracture toughenss, and breakdown voltage have been much improved relative to the conventional polycrystalline materials. Finally, optimization of the compaction parameters and sintering conditions will lead to the consolidation of $Al_2O_3$ nanopowder with higher density and even further enhanced mechanical properties.

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Using Nanosecond Electron Beam to Produce Silver Nanopowder

  • Balezin, M.E.;Timoshenkova, O.R.;Sokovnin, S.Yu.;Lee, Hi-Min;Rhee, C.K.
    • 한국분말재료학회지
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    • 제15권6호
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    • pp.466-470
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    • 2008
  • Experiments with a URT-0.5 accelerator (0.5 MeV, 50 ns, 1 kW) generating a nanosecond electron beam for irradiation of silver nitrate in various liquid solutions (water and toluene) were performed with the aim of producing silver nanopowders. A radiochemical reaction allows making weakly agglomerated pure Ag powders with particles of 10-15 nm and 30-50 nm in size by irradiation in toluene and water respectively. The injection of the nanosecond electron beam energy to the solution is optimal. As the absorbed dose increases, the output of the radiochemical reaction does not grow, but more agglomerated powders are synthesized.

증류수 중 전기폭발에 의한 Cu 나노분말 제조 및 분석 (Preparation and Analysis of Cu Nanopowder by Wire Explosion in Distilled Water)

  • 조주현;진윤식;강충일;이경자;이창규
    • 전기학회논문지
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    • 제59권7호
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    • pp.1272-1275
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    • 2010
  • The Cu powder was prepared in distilled water. It has a wide range of size distribution. The submicron-sized particles in the Cu powder were removed by using continuous type centrifugal separator. The average particle size after classification was approximately 50nm. The XRD analysis showed that pure Cu phase and oxide phase ($Cu_2O$)weremixedinthepowderpreparedbythismethod.

Evaluation of Iron Nickel Oxide Nanopowder as Corrosion Inhibitor: Effect of Metallic Cations on Carbon Steel in Aqueous NaCl

  • Chaudhry, A.U.;Mittal, Vikas;Mishra, Brajendra
    • Corrosion Science and Technology
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    • 제15권1호
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    • pp.13-17
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    • 2016
  • The aim of this study was to evaluate the use of iron-nickel oxide ($Fe_2O_3$.NiO) nanopowder (FeNi) as an anti-corrosion pigment for a different application. The corrosion protection ability and the mechanism involved was determined using aqueous solution of FeNi prepared in a corrosive solution containing 3.5 wt.% NaCl. Anti-corrosion abilities of aqueous solution were determined using electrochemical impedance spectroscopy (EIS) on line pipe steel (API 5L X-80). The protection mechanism involved the adsorption of metallic cations on the steel surface forming a protective film. Analysis of EIS spectra revealed that corrosion inhibition occurred at low concentration, whereas higher concentration of aqueous solution produced induction behavior.

Synthesis and Properties of Multimetal Oxide Nanopowders via Nano-explosive Technique

  • Vasylkiv, Oleg;Sakka, Yoshio;Skorokhod, Valeriy
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.152-153
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    • 2006
  • We demonstrate the methodology of engineering the multi-component ceramic nanopowder with precise morphology by nanoblast calcinations decomposition of preliminary engineered nanoreactors. Multiple explosions of just melted $C_3H_6N_6O_6$ embedded into preliminary engineered nanoreactors break apart the agglomerates due to the highly energetic impacts of the blast waves. Also, the solid-solubility of one component into the other is enhanced by the extremely high local temperature generated during each nano-explosion in surrounding area. This methodology was applied for production of agglomeratefree nano-aggregates of $Gd_{20}Ce_{80}O_{1.95}$ with an average size of 42 nm and $LaSrGaMgO_{3-x}$ nanopowder with an average aggregate size of 83 nm.

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Densification Behavior and Microstructural Development of Nano-agglomerate Powder during Singering

  • Kang, Yun-Sung;Cha, Berm-Ha;Kang, Hyun-Goo;Lee, Jai-Sung
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.282-283
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    • 2006
  • Densification behavior of nano-agglomerate powder during pressureless sintering of Fe-Ni nanopowder was investigated in terms of diffusion kinetics and microstructural development. To understand the role of agglomerate boundary for sintering process, densification kinetics of Fe-Ni nano-agglomerate powder with different agglomerate size was investigated. It was found that activation energy for densification was lower in the small-sized agglomerate powder. The increase in the volume fraction of inter-agglomerate boundary acting as high diffusion path might be responsible for the enhanced diffusion process.

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Control of Crystal Phase and Agglomeration of Iron Oxide Nanoparticles in Gas Phase Synthesis

  • Lee, Chang-Woo;Lee, Jai-Sung
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.424-425
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    • 2006
  • The effects of reaction temperature and precursor concentration on the microstructure and magnetic properties of ${\gamma}-Fe_2O_3$ nanoparticles synthesized as final products of iron acetylacetonate in chemical vapor condensation (CVC) were investigated. Pure ${\gamma}-Fe_2O_3$ phase was obtained at temperature above $900^{\circ}C$ and crystallite size of ${\gamma}-Fe_2O_3$ nanoparticles decreased with lowering precursor concentration. Also, the coercivity decreases with decreasing crystallite size of nanopowder. The lowest coercivity was 7.8 Oe, which was obtained from the ${\gamma}-Fe_2O_3$ nanopowder sample synthesized at precursor concentration of 0.3M. Then, the crystallite size of ${\gamma}-Fe_2O_3$ nanoparticles was 8.8 nm.

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