• 제목/요약/키워드: nano

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나노클레이 첨가량에 따른 나노재료 시멘트 모르타르에 정착된 보강섬유의 인발성능 (Pullout Performance of Reinforcing Fiber Embedded in Nano Materials Cement Mortar with Nano Clay Contents)

  • 오리온;박찬기
    • 한국농공학회논문집
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    • 제55권3호
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    • pp.113-121
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    • 2013
  • Recently, it has been studied for the application of nano-materials in the concrete. Applied a small amount of nano-materials can achieve the goal of high strength, high performance and high durability. The small addition of nano clay improves strength, thermal stability, and durability of concrete because of the excellent dispersion. The present study has investigated the effectiveness, when varying with the contents of nano clay, influencing the pull-out behavior of macro synthetic fibers in nano materials cement mortar. Pullout tests conducted in accordance with the Japan Concrete Institute (JCI) SF-8 standard for fiber-reinforced concrete test methods were used to evaluate the pullout performance of the different nano clay. Nano clay was added to the 0, 1, 2, 3, 4 and 5 % of cement weight. The experimental results demonstrated that the addition of nano clay led to improve the pull-out properties as of the load-displacement curve in the precracked and debonded zone. Also, the compressive strength, flexural strength and pullout performance and of Mix No. 1 and No. 2 increased up to the point when nano clay used increased by 2 and 3 % contents, respectively, but decreased when the exceeded 3 and 4 %, respectively. It was proved by verifying increase of the scratching phenomenon in macro synthetic fiber surface through the microstructure analysis on the surface of macro synthetic fiber.

친환경 GIS Spacer용, 에폭시-나노-마이크로실리카 혼합 콤포지트의 교류 전기적, 기계적 특성 (AC Electrical and Mechanical Properties of Epoxy-Nano-Microsilica Mixed Composites for Eco-Friendly GIS Spacer)

  • 박재준
    • 전기학회논문지
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    • 제67권9호
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    • pp.1181-1188
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    • 2018
  • In order to develop new insulating materials for GIS Spacer using environmentally friendly insulating gas, three kinds of dispersed liquid nano composites of solid epoxy /nano layered silicate filled material were prepared. And the epoxy/nano/micro silica composite was prepared by mixing epoxy/nano 3 phr dispersion/4 kinds of filler contents(40,50,60, 70wt%). The electrical insulation breakdown strengths of the nano and nano/micro mixed composites were evaluated by using 8 kinds of samples including the original epoxy. The mechanical tensile strength of the epoxy / nano / micro silica composite were evaluated, also. The TEM was measured to evaluate the internal structure of nano/micro composites. As a result, it was confirmed that the layered silicate nano particles was exfoliated through the process of inserting epoxy resin between silicate layers and the layers. In addition, dispersion of nano / micro silica resulted in improvement of electrical insulation breakdown strength with increase of filling amount of dense tissue with nanoparticles inserted between microparticles. In addition, the tensile strength showed a similar tendency, and as the content of microsilica filler increased, the mechanical improvement was further increased.

Fabrication of silicon nano-ribbon and nano-FETs by using AFM anodic oxidation

  • 황민영;최창용;정지철;안정준;구상모
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.54-54
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    • 2009
  • AFM anodic oxidation has the capability of patterning complex nano-patterns under relatively high speeds and low voltage. We report the fabrication using a atomic force microscopy (AFM) of silicon nano-ribbon and nano-field effect transistors (FETs). The fabricated nano-patterns have great potential characteristics in various fields due to their interesting electronic, optical and other profiles. The results shows that oxide width and the separation between the oxide patterns can be optimally controlled. The subsequently fabricated silicon nano-ribbon and nano-FET working devices were controled by various tip-sample bias-voltages and scan speed of AFM anodic oxidation. The results may be applied for highly integration circuits and sensitive optical sensor applications.

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EXPERIMENTAL STUDY ON CHF CHARACTERISTICS OF WATER-TI02 NANO-FLUIDS

  • Kim, Hyung-Dae;Kim, Jeong-Bae;Kim, Moo-Hwan
    • Nuclear Engineering and Technology
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    • 제38권1호
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    • pp.61-68
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    • 2006
  • CHF characteristics of nano- fluids were investigated with different volumetric concentrations of $TiO_2$ nanoparticles. Pool boiling experiments indicated that the application of nano-fluids, instead of pure water, as a cooling liquid significantly increased the CHF. SEM (scanning electron microscope) observations subsequent to the pool boiling experiments revealed that nanoparticles were coated on the heating surface during pool boiling of nano-fluids. In order to investigate the roles of nanoparticles in CHF enhancement ofb nano-fluids, pool boiling experiments were performed using (a) a nanoparticle-coated heater, prepared by pool boiling of nano-fluids, immersed in pure water and (b) a nanoparticle-coated heater immersed in nano-fluids. The results demonstrated two different roles of nanoparticles in CHF enhancement using nano-fluids: the effect of nanoparticles coated on the heater surface and the effect of nanoparticles suspended in nano- fluids.

표면개질된 나노 알루미나의 에폭시-나노 콤포지트 유전 특성 (Dielectric Properties of Epoxy-Nano Composites for Surface Modified Nano Alumina)

  • 박재준
    • 한국전기전자재료학회논문지
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    • 제29권10호
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    • pp.613-619
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    • 2016
  • The aim of this study is to improve of dielectric properties using epoxy/nano alumina composites with adding glycerol diglycidyl ether (GDE:1,2 g). This paper deals with the effects of dielectric properties(${\epsilon}^{\prime}_r$ and $tan{\delta}$) for epoxy/nano alumina contents (1,3 phr) and GDE addition (1,2 g)composites. 5 kinds specimen were prepared with containing epoxy resins, epoxy nano alumina composites. Average particle size of nano used were 30 nm. The nano alumina used were gamma phase particles of spherical shape. The suppression of epoxy chain motion by addition of nano alumina+GDE decreased dielectric loss and relative permittivity magnitude.

Novel Synthesis and Properties of $Si_3N_4$-based Nano/Nano-Type Composites

  • Yoshimura, Masahi
    • 한국분말재료학회지
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    • 제8권3호
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    • pp.210-213
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    • 2001
  • $Si_3N_4$/TiN nano/nano-type composites were successfully fabricated by the combination of a mechano-chemical grinding (MCG) method and a short time sintering process, and their wear resistance was evaluated. Powder mixtures of $\alpha-Si_3N_4$and Ti were prepared using mechano-chemical grinding process and the resulting nanocomposite powder mixtures were consolidated using pulsed electric current sintering (PECS). TEM observation showed that the nano/nano-type composites consisted of homogeneous and very fine matrix grains with the size less than 100 nm. The obtained $Si_3N_4$-based nano/nano-type showed high wear resistance and electric discharge machinability.

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