• Title, Summary, Keyword: nano material

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Diameter Control of Carbon Nanotubes Using Surface Modified Fe Nano-Particle Catalysts with APS (APS로 표면 처리한 Fe 나노 입자 촉매를 이용한 CNT의 직경제어)

  • Lee, Sunwoo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.6
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    • pp.478-481
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    • 2013
  • Diameter controlled carbon nanotubes (CNTs) were grown using surface modified iron nano-particle catalysts with aminpropyltriethoxysilane (APS). Iron nano-particles were synthesized by thermal decomposition of iron pentacarbonyl-oleic acid complex. Subsequently, APS modification was done using the iron nano-particles synthesized. Agglomeration of the iron nano-particles during the CNT growth process was effectively prevented by the surface modification of nano-particles with the APS. APS plays as a linker material between Fe nano-particles and $SiO_2$ substrate resulting in blocking the migration of nano-particles. APS also formed siliceous material covering the iron nano-particles that prevented the agglomeration of iron nano-particles at the early stages of the CNT growth. Therefore we could obtain the diameter controlled CNTs by blocking agglomeration of the iron nano-particles.

Effects of Nano-silica/Nano-alumina on Mechanical and Physical Properties of Polyurethane Composites and Coatings

  • Swain, Sarojini;Sharma, Ram Avatar;Bhattacharya, Subhendu;Chaudhary, Lokesh
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.1
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    • pp.1-8
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    • 2013
  • The present approach shows the use of nano-silica/nano-alumina in polyurethane (PU) matrix, which lead to significant improvements in the mechanical and thermal properties of the nano-composite. It is observed that with incorporation of 1% of nano-alumina into the PU matrix, there is an improvement in the tensile strength of around 50%, and for nano-silica the improvement is around 41%, at the same concentration. The morphological data shows that above 3% of the nano particles there are agglomerations in the nanocomposite. Again with the absorption of moisture, there is a decrease in the thermal and mechanical properties of the PU resin, but in this research work it is observed that with the incorporation of the nano particles, in the presence of absorbed moisture there is an improvement in mechanical and thermal properties of the composite, over that of the PU matrix.

Synthesis and Photocatalytic Effect of Brookite Phase $TiO_2$ Colloidal Sol by Hydrothermal Method (수열합성법을 이용한 Brookite $TiO2$ 졸의 제조 및 광촉매 효과)

  • Yoon, Cho-Rong;Oh, Hyo-Jin;Czoska, Anna;Park, Kyung-Soon;Lee, Nae-Sung;Kim, Sun-Jae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.117-120
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    • 2006
  • $TiOCl_2$를 중화시키고 과산화수소와 반응시켜 Ti peroxo 전구체를 수열합성법을 이용하여 autoclave 반응기 내에서 가열하여 $TiO_2$ 졸을 제조하였다. Autoclave 반응기 내에 압력을 가하면 브룩카이트상 $TiO_2$졸이 형성됨을 확인하였고, 중화과정에서 NaCl을 첨가하여 Ti 수산화물 격자 내에 Na 이온을 포획되어 브룩카이트상이 나타남을 알 수 있었다. Na 이온의 첨가량에 따라 브룩카이트 결정상 함량이 달라져 광촉매 활성도 달라짐을 브룩카이트상 $TiO_2$가 코팅된 박막의 기상벤젠 광분해 실험을 통해 확인하였고 미세구조, 결정성, 광흡수도률 측정하여 특성평가를 실시하였다.

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A Study on Performance of Building Material using nano-hydrated Aluminum for Fire-Resistance (나노 수산화알루미나를 이용한 건설소재의 내화성능 개선연구)

  • Jo, Byung-Wan;Park, Jong-Bin
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.826-829
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    • 2004
  • An increasing interest in fire safety engineering can currently be identified in Korea and overseas. The fire-resistant characteristics of spray coating material for fire protection with or without nano $Al(OH)_3$ colloid has been experimentally investigated and the results are presented in this paper. The fire-resistance characteristics of spray coating material with nano $Al(OH)_3$ were superior to those without $Al(OH)_3$. Especially, spray coating material with nano material showed that thermal characteristic in the early days was remarkably excellent.

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The evaluation of electrical properties for $LiNi_xMn_{2-x}O_4$ Nano powders by Ultra sonic pyrolysis (초음파 분무연소법에 의한 $LiNi_xMn_{2-x}O_4$ 분말의 전기적 특성 평가)

  • Oh, Hyo-Jin;Lee, Nam-Hee;Yoon, Cho-Rong;Czoska, Anna;Nam, Sang-Chul;Park, Kyeong-Soon;Lee, Nae-Sung;Kim, Sun-Jae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.113-116
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    • 2006
  • 자발착화 연소반응법 (Glycine Nitrate Process)을 응용한 초음파분무열분해장치를 이용하여 이차전지의 양극재료인 Ni치환형 $LiMn_2O-4$ 분말을 합성하였고, 각각의 하소온도에 따른 분말의 특성을 평가하였다. 전구용액은 산화제로 $Mn(NO_3)_2{\cdot}6H_20$EX>, $LiNO_3$, $Ni(NO_3)_2{\cdot}6H_20$를 사용하였고, 자발착화 에너지를 공급하기 위한 연료로는 glycine를 사용하였다. 분말의 결정상을 확인하기 위해 X-선 회절 시험을 시행하였으며, 각각의 조성별로 ICP측정결과 여러 조성들($LiNi_xNm_{2-x}O_4\;0{\leq}x{\leq]0.5$) 중 $LiNi_{0.3}Nm_{1.7}O_4$의 분말이 비교적 우수한 특성을 나타내었지만, 전기화학적 특성 평가 결과 이론용량값에 미치지 못하는 용량값을 나타내었다. 이것은 분말 합성 시 미량의 미 반응된 유기물들이 분말 표면에 피복되어 전기적 성질을 변화시키고 있기 때문임을 확인하였다. 이러한 특성을 개선하고자 추가적으로 하소 공정을 실시하여 전지의 성능를 평가 하였다. 분말의 미세구조와 형태, 크기, 전기 화학적 특성을 관찰하여 하소 전 후의 분말을 비교하였다.

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The Effect of Particle Size on Rheological Properties of Highly Concentrated Ag Nanosol (초 고농도 Ag 나노 졸의 입자크기 제어가 잉크 점성거동에 미치는 영향)

  • Song, Hae-Chon;Nham, Sahn;Lee, Byong-Seok;Choi, Young-Min;Ryu, Beyong-Hwan
    • Journal of the Korean Ceramic Society
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    • v.46 no.1
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    • pp.41-46
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    • 2009
  • The rheological properties of highly concentrated Ag nano sol depending on particle size were studied. The Ag nano sol was prepared by reducing the Ag ion in aqueous solution. The size of Ag nano particle was controlled by two steps of nucleation and growth, and the thickness of adsorption layer was varied by molecular weight of polyelectrolytes. The polyelectrolytes acted as not only ionic complex agent in ionic state and but also dispersant after formation of Ag nano sol. The effective volume was controlled by combination of varying the molecular weight of polyelectrolytes and the size Ag nano sol. The particle size and the viscosity of nano sol were characterized by particle size analyzer, HR-TEM and cone & plate viscometer. It was found that the 10 nm and 40 nm-sized Ag nano sols were prepared by controlling the nucleation and growth steps, respectively. Finally, we could prepare highly concentrated Ag nano sol over 50 wt%.

Effect of Nano/micro Silica on Electrical Property of Unsaturated Polyester Resin Composites

  • Sharma, Ram Avatar;D'Melo, Dawid;Bhattacharya, Subhendu;Chaudhari, Lokesh;Swain, Sarojini
    • Transactions on Electrical and Electronic Materials
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    • v.13 no.1
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    • pp.31-34
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    • 2012
  • The addition of nano/micro silica into unsaturated polyester resin (UPR) results in the improvement of the electrical properties of Silica-UPR composites. The surface, volume resistivity, dielectric strength, dissipation factor and dry arc resistivity of nano silica-UPR composites were found to improve significantly. The effects of the nano and micro fillers in UPR have been evaluated. They are presented in this paper. To evaluate the electrical properties of the nano & micro composites, all the measurements were done as per the prescribed methods in ASTM. It was observed that the addition of nano silica improves the electrical properties as compared to micro silica. The better dispersion of silica particles in unsaturated polyester resin enhances the electrical properties of silica-UPR composites.