• Proceedings of the Optical Society of Korea Conference
• /
• 2000.02a
• /
• pp.214-215
• /
• 2000

As silica based optical fibers and preforms are processed at a high temperature, residual stresses are bulit in the strucure when cooled down to the room temperature. The magnitude of the residual stress depends on the difference in the thermal expansion coefficients between core and cladding glass as well as on the temperature difference. Residual stress distribution determines the intrinsic strength and could affect the long term reliability of optical fibers. And furthermore, stress can introduces anisotropy into optical fibers by photoelastic effects. The analysis of thermal stress has been intensively studied for multimode fibers$^{(1)}$ and the authors and co-wokers recently reported the stress distribution in a depressed inner cladding structure$^{(2)}$ . The compositions of the glass in the previous studies, however, have been restricted to conventional glass formers, such as GeO2, B2O3, P2O5, Fluorine. (omitted)

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1482-1483
• /
• 2008

This report describes the design, fabrication and experimental results of an implantable micro pressure regulator. It consists of three silicon substrates, a glass substrate, and a PDMS layer. Silicon and glass substrates are fabricated by using bulk micro machining and sandblasting. The PDMS layer is used as a intermediate layer for Si-Si and Si-glass bonding processes. This micro regulator is a key component of the portable drug delivery systems for low power consumption. The device has some advantages, such as a passive type device, no power consumption, and simple structure.

• Transactions of Materials Processing
• /
• v.16 no.4 s.94
• /
• pp.309-312
• /
• 2007

Deformation behavior of $Zr_{55}Cu_{30}Al_{10}Ni_5$(at. %) bulk metallic glass(BMG) fabricated by suction casting method has been investigated at elevated temperatures in this study. The BMG was first verified to have an amorphous structure with the analysis of X-ray diffraction(XRD) and differential scanning calorimetry(DSC) data. A series of compression tests has consequently been performed in the region of supercooled liquid temperature to investigate the behavior of high temperature deformation. A transition from Newtonian to non-Newtonian flow appeared to take place depending upon both the strain rate and test temperature. A processing map based on a dynamic materials model has been constructed to estimate a feasible forming condition for this BMG alloy.

• Journal of the Korea Furniture Society
• /
• v.12 no.2
• /
• pp.61-71
• /
• 2001

In furniture design, it is very important to choose adequate materials. Transparent materials provide expectations and reveals unique effects unlike others. As transparent materials, glass and acrylic have light and fresh impression from their transparency, and are frequently used in structuring neat space. Despite its good merits, glass is not able to satisfy designers desire in making various shape and structure. It has defect in manufacturing process because it requires professional, specialized studio. Compared to glass, acrylic has its merit in processing and stability, and also is very economical. Acrylic is easily used with woodworking tool. In addition, acrylic has unique texture. This study is on the attempt to apply acrylic to the furniture as artistic element.

• Journal of the Korean institute of surface engineering
• /
• v.40 no.3
• /
• pp.113-116
• /
• 2007

Titanium dioxide ($TiO_2$) films were deposited by RF reactive magnetron sputtering on non-alkali glass and single crystal MgO (100) substrate at substrate temperature of $400^{\circ}C$. Micro structures of $TiO_2$ films were investigated by XRD, FE-SEM, and Pole figure measurements. $TiO_2$ films deposited on glass substrate showed preferred orientation of anatase (101), whereas $TiO_2$ films deposited on the MgO single crystal substrate showed hetero-epitaxial anatase (100). $TiO_2$ film grown on MgO substrate showed higher photoctalytic activity than that of glass substrate.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.9
• /
• pp.1281-1283
• /
• 2003

Proteins in highly oriented lipid bilayer samples are useful to study membrane protein structure determination. Planar lipid bilayers aligned and supported on glass slide were prepared. These stack of glass slide with planar lipid bilayers are not well fit for commercial solid-state NMR probe with round coil. Therefore, homebuilt solid-state NMR probe was built and used for a stack of thin glass plates and RF coil is wrapping directly around the flat square sample. The overall filling factor of the coil is much better and the large surface area enhances the extent to orientation by providing uniform environments for the phospholipids and the high ratio of circumference to area reduces edge effects. $^1H\;and\;^{15}N$ double resonance probe for 400 MHz NMR (9.4T) with a flat coil (coil size: 11 mm ${\times}$ 20 mm ${\times}$ 4 mm) is constructed and tested.

• Journal of Korean Association for Spatial Structures
• /
• v.13 no.4
• /
• pp.41-47
• /
• 2013

For the artistic column used by Glass Fiber Reinforced Plastic(GFRP), the connection of steel with GFRP were needed. Due to the fabricating characteristics of hand laminating, GFRP surfaces had to be connected. Because there were no existed data of these connection, experimental study has to be followed so that the structural strength and buckling mode could be investigated. In this paper, therefore, the axial tests of steel with GFRP were performed. The connection of GFRP's surfaces could be also tested as well. As a result, it could be figured out that the strength of these connections were determined by the adhesive strength.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.04a
• /
• pp.1-4
• /
• 2004

In this paper we developed Composite-Smart-Structures(CSS) using sandwich structure composed of Glass/Epoxy laminates and Nomex honeycomb and microstrip antenna. Transmission/reflection theory shows that antenna performances can be improved due to multiple reflection by Glass/Epoxy facesheet, and honeycomb is used for air gap between antenna and facesheet. Stacked radiating patches are used for the wideband. Facesheet and honeycomb thicknesses are selected considering both wideband and high gain. Measured electrical performances show that CSS has wide bandwidth over $10\%$ and higher gain by 3.5dBi than initially designed antenna, and no doubt it has excellent mechanical performances by sandwich effect given by composite laminates and honeycomb core. The CSS concept can be extended to give a useful guide for manufacturers of structural body panels as well as antenna designers, promising innovative future communication technology.

• Journal of the Korean Ceramic Society
• /
• v.29 no.8
• /
• pp.623-629
• /
• 1992

The possible use of bioglass as implant materials is due to its biocompatibility to human body. Even if many animal studies for the bioglasses have been performed, their compositional dependences of structures and physical properties are not fully understood. In the present work, physical property measurements such as density and thermal expansion coefficient were carried out for the bioglasses, with substitution of CaO for Na2O in bioglass composition (46.1%SiO2, 24.4%Na2O, 26.9%CaO, 2.6%P2O5:mol%). Hydroxyapatite formation on the glass surface was also examined after reacted in Tris-buffer solution. As CaO was substituted for Na2O, the bond strength between nonbridging oxygen and modifier became stronger to make glass structure rigid, and resulted in increase in density and decrease in thermal expansion coefficient. When the bioglasses were reacted in Tris-buffer solution, hydroxyapatite was formed on the bioglass surface for all prepared glasses in 2 hours, independently on CaO content, and the thickness of hydroxyapatite layer was decreased a little, while the thickness of SiO2 rich layer was decreased sharply with CaO content.

• Elastomers and Composites
• /
• v.55 no.4
• /
• pp.277-280
• /
• 2020

In this study, mesoporous hollow silica spheres were synthesized using a polystyrene core and cetyltriammonium chloride (CTACl) as a pore template, and a low-cost water glass instead of expensive tetraethyl orthosilicate (TEOS) as a precursor. In addition, the material was synthesized by varying the concentration of polystyrene. Later, the polystyrene core and CTACl were removed by firing in a high-temperature heat-treatment process. The synthesized product was analyzed by various methods, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), and N2-sorption analysis. It was confirmed that the hollow silica sphere had a hexagonal structure with a Brunauer-Emmett-Teller (BET) specific area of 1623 ㎡/g.