• Title/Summary/Keyword: nano-glass

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Development of nano/micro forming and evaluation technology of Zr-base bulk metallic glass (Zr계 벌크 비정질 합금의 미세성형 및 평가기술 개발)

  • Ok M.-R.;Suh J. Y.;Chung S. J.;Hong K. T.;Ji Y. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.10a
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    • pp.44-47
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    • 2004
  • Although bulk metallic glasses have many outstanding aspects in their chemical, mechanical or functional properties, some critical problems still hinder their wide application. The most important one is the brittle nature of them, which is the serious problem to structural application. So, to use viscous flow is now the only competent way to form bulk metallic glass. In this study, we investigated the basic nature of viscous flow of Zr-base bulk metallic glass, vitrelloy 1, in terms of process variables. The results were used to design the thermo-mechanical process composed of heating, holding, pressing, and cooling, which have unique influence on the glass transition and crystallization behavior. We adopted small load scale and dies with nano/micro patterns on them. The results were evaluated using several analytical methods.

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Effect of nano glass cenosphere filler on hybrid composite eigenfrequency responses - An FEM approach and experimental verification

  • Pandey, Harsh Kumar;Hirwani, Chetan Kumar;Sharma, Nitin;Katariya, Pankaj V.;Dewangan, Hukum Chand;Panda, Subrata Kumar
    • Advances in nano research
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    • v.7 no.6
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    • pp.419-429
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    • 2019
  • The effect of an increasing percentage of nanofiller (glass cenosphere) with Glass/Epoxy hybrid composite curved panels modeled mathematically using the multiscale concept and subsequent numerical eigenvalues of different geometrical configurations (cylindrical, spherical, elliptical, hyperboloid and flat) predicted in this research article. The numerical model of Glass/Epoxy/Cenosphere is derived using the higher-order polynomial type of kinematic theory in association with isoparametric finite element technique. The multiscale mathematical model utilized for the customized computer code for the evaluation of the frequency data. The numerical model validation and consistency verified with experimental frequency data and convergence test including the experimental elastic properties. The experimental frequencies of the multiscale nano filler-reinforced composite are recorded through the impact hammer frequency test rig including CDAQ-9178 (National Instruments) and LABVIEW virtual programming. Finally, the nano cenosphere filler percentage and different design associated geometrical parameters on the natural frequency data of hybrid composite structural configurations are illustrated through a series of numerical examples.

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
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    • 2004.10a
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    • pp.1331-1334
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    • 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.

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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
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    • v.22 no.10 s.175
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    • pp.121-128
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    • 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.

Printability of synthesized Silver Nano sol in Micro-patterning of Electrode on ITO Glass

  • Ryu, Beyong-Hwan;Park, Han-Sung;Byun, Jong-Hoon;Choi, Young-Min;Kong, Ki-Jeong;Lee, Jeong-O;Chang, Hyun-Ju
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.981-984
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    • 2004
  • We have studied a printability of synthesized silver nano solon ITO glass substrate. The highly concentrated polymeric dispersant-assisted silver nano sol was prepared by variation of molecular weight and control of initial nucleation and growth of silver nanoparticles, to achive dispersion stability and controlling the size of silver nanoparticles. The synthesized silver nano-sol was tested for printability to explore the possibility of micro-electrodes patterning on ITO glass substrate. The silver micro-electrode with 50${\sim}100{\mu}m$ line width was formed on ITO glass substrate.

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Color modification inside a transparent glass(BK7) using a femtosecond laser (펨토초 레이저 기반 투명유리(BK7) 내부의 컬러 미세형상 가공)

  • Kim, Hoon-Young;Yoon, Ji-Wook;Choi, Won-Seok;Park, Jung-Kyu;Choi, Ji-Yeon;Kim, Jae-Goo;Whang, Kyoung-Hyun;Cho, Sung-Hak
    • Laser Solutions
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    • v.15 no.3
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    • pp.16-19
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    • 2012
  • We have successfully formed brown colored patterns inside of a transparent borosilicate glass generally known as BK7, laying the focus of near infrared Ti: sapphire femtosecond laser beam in the bulk BK7 glass. It is important to keep the laser power well below the damage threshold of BK7 in forming the color center. According to the low laser power, there was no laser induced mechanical damage such as cracks or threads in the color formed area. From the absorbance spectrum and its gaussian fitting, we found the band gap of BK7, 4.21eV, and three absorption edges.

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Fabrication and Characterization of Superhydrophobic Glass Surfaces Using Silicon Micro-mold and Thermal-reflow Process (실리콘 마이크로 몰드와 유리의 열-재흐름 현상을 이용한 초소수성 유리 표면 제작 및 젖음 특성 평가)

  • Kim, Seung-Jun;Kong, Jeong-Ho;Lee, Dongyun;Kim, Jong-Man
    • Korean Journal of Metals and Materials
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    • v.50 no.8
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    • pp.591-597
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    • 2012
  • This paper presents regularly micro-textured glass surfaces ensuring the superhydrophobic properties in the Cassie-Baxter regime. The proposed surfaces were fabricated simply and efficiently by filling the glass material into a silicon micro-mold with periodic micro-cavities based on a thermal-reflow process, resulting in a successful demonstration of the textured glass surface with periodically-arrayed micro-pillar structures. The static and dynamic wetting properties of the micro-textured glass surfaces were characterized by measuring the static contact angle (SCA) and contact angle hysteresis (CAH), respectively. In addition, the surface wettability was estimated theoretically based on Wenzel and Cassie-Baxter wetting theories, and compared with the experimental ones. Through the experimental and theoretical observations, it was clearly confirmed that the proposed micro-textured glass surfaces showed the slippery superhydrophobic behaviors in the Cassie-Baxter wetting mode.

Optical diffraction gratings embedded in BK-7 glasses by tightly focused femtosecond laser

  • Yoon, Ji Wook;Choi, Won Suk;Kim, Hoon Young;Cho, Sung-Hak
    • Laser Solutions
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    • v.17 no.2
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    • pp.19-25
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    • 2014
  • Optical embedded diffraction gratings with the bulk modification in BK-7 glass plates excited by tightly focused high-intensity femtosecond (130fs) Ti: sapphire laser (peak wavelength = 790nm) were demonstrated. The structural modifications with diameters ranging from 400nm to $4{\mu}m$ were photo-induced after plasma formation occurred upon irradiation with peak intensities of more than $1{\times}1013W/cm^2$. The graded refractive index profile was fabricated to be a symmetric around from the center of the point at which low-density plasma occurred. The maximum refractive index change was estimated to be $1.5{\times}10^{-2}$. The two optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.

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Ultra-Precise Polishing of Mica Glass Ceramics Using MR Fluids and Nano Abrasives (MR fluid를 이용한 Mica Glass Ceramics의 초정밀 연마)

  • Beak, Si-Young;Song, Ki-Hyeok;Kim, Ki-Beom;Kim, Byung-Chan;Kang, Dong-Sung;Hong, Kwang-Pyo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.5
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    • pp.85-90
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    • 2017
  • Mica-glass ceramics has features such as micro-sized crystals, high strength, chemical resistance, semitransparent optical properties, etc. Due to its superior material properties, mica glass ceramics have increasing applications in dental and medical components, insulation boards, chemical devices, etc. In many applications, especially for dental and medical components, ultra-precise polishing is required. However, it is known to be a very difficult-to-grind material because of its high hardness and brittle properties. Thus, in this study, a newly developed ultra-precise polishing method is applied to obtain nano-level surface roughness of the mica glass ceramics using magnetorheological (MR) fluids and nano abrasives. Nano-sized ceria particles were used for the polishing of the mica glass ceramics. A series of experiments were performed under various polishing conditions, and the results were analyzed. A very fine surface roughness of Ra=6.127 nm could be obtained.

The Effects of (Ba0.4Ca0.6)SiO3 Nano Spheroidization Glass Additives on the Microstructure and Microwave Dielectric Properties of Ba(Zn1/3Ta2/3)O3 Ceramics

  • Choi, Cheal Soon;Kim, Ki Soo;Rhie, Dong Hee;Yoon, Jung Rag
    • Journal of Electrical Engineering and Technology
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    • v.9 no.5
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    • pp.1719-1723
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    • 2014
  • In this study, the microwave dielectric properties of nano spheroidization glass powders added $Ba(Zn_{1/3}Ta_{2/3})O_3$ ceramics prepared by solid state reaction have been investigated. Adding $(Ba_{0.4}Ca_{0.6})SiO_3$ nano spheroidization glass powders could effectively promote the densification even in the case of decreasing the sintering temperature. When the glass frit is 0.3 wt% and sintering is carried out at a temperature of $1500^{\circ}C$ for 6 hr, a temperature stable microwave dielectric ceramic could be obtained, which has a dielectric constant (${\varepsilon}_r$) of 30.2, a quality factor ($Q{\times}f_0$) of 124,000 GHz and a temperature coefficient of resonance frequency (${\tau}_f$) of $2ppm/^{\circ}C$.