• Title/Summary/Keyword: nano fiber

Search Result 449, Processing Time 0.025 seconds

Permittivities of the Carbon Nano Fiber/Epoxy Composite According to the Dispersion Methods (분산 방법에 따른 카본 나노 섬유/에폭시 복합재료의 유전율)

  • 김태욱;김진봉;공진우;정재한;김준현
    • Proceedings of the Korean Society For Composite Materials Conference
    • /
    • 2003.10a
    • /
    • pp.55-58
    • /
    • 2003
  • This paper presents a study on the permittivities of the carbon nano fiber/epoxy composite at microwave frequency. The permittivities of composite materials depend on the concentrations and the dispersion methods of the carbon nano fibers. The experimental values of complex permittivities were obtained for the specimen made by dispersion method using ethyl alcohol as dispersion media and compared with the results by simple mechanical mixing method.

  • PDF

Addition of nano particle to increase the cavitation resistance of urethane (나노입자 첨가를 통한 우레탄수지의 캐비테이션 저항 향상)

  • Lee, Iksoo;Kim, Nackjoo;Pak, Daewon
    • Journal of the Korean Applied Science and Technology
    • /
    • v.31 no.4
    • /
    • pp.679-687
    • /
    • 2014
  • In this study, a new paint which is able to resist the cavitation erosion is tried to be developed by using urethane added with nano particles such as multi-wall and single-wall carbon nano tube and spherical and fiber type graphite. The new paint synthesized was characterized with physical properties and resistivity to cavitation erosion($t_{50}$). Among nano particles, fiber type graphite($t_{50}$ 292min) showed high hardness and wear resistance compared with spherical type($t_{50}$ 182min). For carbon nano tube, single-wall type($t_{50}$ 286min) was higher than multi-wall type in wear resistance. Fiber-type graphite was the best nano-particle for paint with resistivity to cavitation erosion. In the application test of paint, the manually painted sample showed surface with smooth but the surface of sample prepared with spray was not smooth. During spray, dust was fixed on the surface.

Temperature Sensor Based on Fabry-Perot Interferometer Using a Fiber Optic Patch Cord (광섬유 패치코드를 이용한 Fabry-Perot 간섭계 온도센서)

  • Kim, Ju Ha;Jung, Eun Joo;Kim, Myoung Jin;Hwang, Sung Hwan;Lee, Woo Jin;Kim, Gye Won;An, Jong Bae;Choi, Eun Seo;Rho, Byung Sup
    • Journal of Sensor Science and Technology
    • /
    • v.23 no.2
    • /
    • pp.110-113
    • /
    • 2014
  • In this paper, we propose and demonstrate a Fabry-Perot interferometer (FPI) optical fiber tip sensor fabricated by a blade-sawing technique using a fiber optic patch cord for high-resolution temperature measurement. The sensor head consists of a short air FP cavity near the tip of a single-mode fiber patch cord tip. The temperature which we can measure is determined through a phase variation of the interference fringes in the reflective spectrum of the sensor. The fiber optic FPI sensor in this work can monitor the environmental temperature very accurately from 40 to $120^{\circ}C$. As a result, the temperature sensitivity is obtained as $38.2pm/^{\circ}C$.

Electromagnetic-wave Shielding by Nano Particles-contained Glass Fiber Reinforced Composite Materials (나노입자 첨가 유리섬유강화 복합재료의 전자기파 차폐특성)

  • 정우균;안성훈;원명식
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2004.10a
    • /
    • pp.1331-1334
    • /
    • 2004
  • The research on electromagnetic shielding has been advanced for military applications as well as for commercial products. Utilizing the reflective properties and absorptive properties of shielding material, the replied signal measured at the rear surface or at the signal source can be minimized. The shielding effect was obtained from materials having special absorptive properties or from structural characteristics such as stacking sequence. Recently researchers studied the electromagnetic properties of nano size particles. In this research {glass fiber}/{epoxy}/{nano particle} composites(GFR-Nano composites), was fabricated using various nano particles, and their properties in electromagnetic shielding were compared. For the visual observation of the nano composite materials, SEM(Scanning Electron Microscope) and TEM(Transmission Electron Microscope) were used. For the measurement of electromagnetic shielding, HP8719ES S-parameter Vector Network Analyser System was used on the frequency range of 8 GHz~12GHz. Among the nano particles, carbon black and Multi-Walled Carbon Nano-Tube (MWCNT) revealed outstanding electromagnetic shielding. Although silver nano particles (flake and powder) were expected to have effective electromagnetic shielding due to their excellent electric conductivities, test showed little shielding effect.

  • PDF

Comparison of Electromagnetic-wave Shielding Effect in Glass Fiber Reinforced Nano Composites (유리섬유강화 나노 복합재료의 전자기파 차폐효과 비교)

  • Jung Woo-Kyun;Won Myung-Sik;Ahn Sung-Hoon
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.22 no.10 s.175
    • /
    • pp.121-128
    • /
    • 2005
  • The research on electromagnetic shielding has been advanced for military applications as well as for commercial products. Utilizing the reflective properties and absorptive properties of shielding material, the replied signal measured at the rear surface or at the signal source can be minimized. The shielding effect was obtained from materials having special absorptive properties and structural characteristics such as stacking sequence. Recently researchers studied the electromagnetic properties of nano size particles. In this research {glass fiber}/{epoxy}/{nano particle} composites(GFR-Nano composites) was fabricated using various nano particles, and their properties in electromagnetic shielding were compared. For the visual observation of the nano composite materials, SEM(Scanning Electron Microscope) and TEM(Transmission Electron Microscope) were used. For the measurement of electromagnetic shielding, HP8719ES S-parameter Vector Network Analyser System was used on the frequency range of 8 GHz${\~}$12GHz. Among the nano particles, carbon black and Multi-Walled Carbon Nano-Tube (MWCNT) revealed outstanding electromagnetic shielding. Although silver nano particles (flake and powder) were expected to have effective electromagnetic shielding due to their excellent electric conductivities, test results showed little shielding characteristics.

Fabrication of Ceramic Particles Deposited Nano-web using Electrospinning Process and Its Far-infrared Ray Emission Property (원적외선 방출 특성을 갖는 나노 웹의 제조 및 원적외선 방사 특성에 관한 연구)

  • Hong, So-Ya;Lee, Chang-Hwan;Kim, Joo-Yong
    • Textile Coloration and Finishing
    • /
    • v.22 no.2
    • /
    • pp.118-122
    • /
    • 2010
  • The interest in textile which has far-infrared ray emissive property has been increased in the field of biophysics and medicine. In this study, far-infrared ray emissive polyurethane nano-web was obtained using electrospinning of polyurethane(PU) solution mixed with ceramics powder and far-infrared ray emissive properties of nano-web were evaluated by measuring far-infrared ray emission power and emissivity(%). To investigate the influence of concentration of ceramics powder in PU solution and temperature for far-infrared ray emissive properties, far-infrared ray emissivity was measured at varied temperature using various nano-web including varied concentration of ceramics powder. Polyurethane nano-web was characterized by SEM to observe the deposition of ceramics powder on polyurethane nano-web surface. The far-infrared ray emissivity was increased with the concentration of ceramics powder in the nano-web. The far-infrared ray emission power was enhanced with increasing temperature of the samples; however, far-infrared ray emissivity was decreased with increasing temperature because the increase of emission power of ceramic containing nano-web was lower than the emission power of black body one.

The Effects of Concentration of HAuCl4 Solution and UV Irradiation Time on Generation of Nano Gold Particles (나노 금 입자생성에 HAuCl4 용액의 농도와 UV 조사시간이 미치는 영향)

  • An, Jeong-Min;Lee, Chang-Whan;Kim, Joo-Yong
    • Textile Coloration and Finishing
    • /
    • v.21 no.6
    • /
    • pp.39-45
    • /
    • 2009
  • The importance of nano gold particles has been increased in the field of bio physics and medicine, recently. In this regard, the study aims to analyze how the harmless nano gold particles can be transformed by respective variables. In this study, electrospun PU nano-webs were impregnated with aqueous $HAuCl_4$ solution and UV light was irradiated on the webs. Au-ions were reduced to nano particles by photocatalytic reduction and these nano gold particles were characterized by SEM, UV-vis, Zetasizer, Spectrophotometer, EDS. $HAuCl_4$ solution concentration and UV irradiation time have heen examined to change the amount of absorption. Nano gold particles size and UV-Vis absorbances were increased with $HAuCl_4$ solution concentration and UV irradiation time.