• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1281-1282
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• 2013

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.71-75
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• 2005

For the damage tolerance improvement of conventional laminated composites, stitching process have been utilized for providing through-thickness reinforcements. 2D preforms were stacked with S-2 glass plain weave and S-2 glass MWK (Multi-axial Warp Knit) L type. 3D preforms were fabricated using the stitching process. All composite samples were fabricated by RTM (Resin Transfer Molding) process. To examine the damage resistance performance the low speed drop weight impact test has been carried out. For the assessment of damage after the impact loading, specimens were examined by scanning image. CAI (Compressive After Impact) tests were also conducted to evaluate residual compressive strength. Compared with 2D composites, the damage area of 3D composites was reduced by 20-30% and the CAI strength showed 5-10% improvement.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.181-182
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• 2000

The glass compositions of $PbO-SiO_2-B_2O_3$ system and $P_2O_5-PbO-ZnO$ system for the transparent dielectric materials for front panel and $P_2O_5-ZnO-BaO$ and $SiO_2-ZnO-B_2O_3$ for the reflective dielectric materials for back panel of PDP(Plasma Display Panel) were investigated. As a transparent dielectric materials for front panel, $PbO-SiO_2-B_2O_3$ glass showed good dielectric properties, high transparency and proper thermal expansion matching to soda-lime glass substrate. And the reflective dielectric materials for back panel were prepared from parent glass of $SiO_2-ZnO-B_2O_3$ system and oxide filler. It was found that these glass-ceramics are useful materials for reflective dielectric layers, as those have a similar thermal expansion to soda-lime glass plate, high reflectance, low sintering temperature.

• Journal of the Korean Ceramic Society
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• v.17 no.4
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• pp.203-207
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• 1980

The optical absorption of high index glasses of the system TiO2-BaO-B2O3 prepared from the raw materials for an optical waveguide glass has been measured in the near ultraviolet region. The amount of Ti3+ in the glass could be reduced to a level less than 5 ppm by melting a batch added with pure nitric acid, using a fused quartz crucible in an oxygen gas atmosphere. The ultra-pure glass of 10mm thick prepared in such a way did not show any appreciable color even for the one containing 30 mol% TiO2 and having refractive index nD of 1.84 and Abbe's number vD of 28.8. The wavelength of ultraviolet absorptin edge was longer for the glass of higher index and higher dispersdion. The melting of a TiO2 containing glass in a platinum crucible resulted in a coloration of the glass due to the dissolved plutinum from the crucible, which was more intense for the one containing larger amount of TiO2.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.661-671
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• 2015

To evaluate the shear performance of the textile glass fiber and the sheet glass fiber reinforced glulam bolted connections, a tension type shear test was conducted. The average yield shear strength of the bolted connection of reinforced glulam was increased by 12% ~ 31% compared to the non-reinforced glulam. It was confirmed that the shear performance of 5D end distance of the glass fiber reinforced glulam connection corresponds to that of 7D of the non-reinforced glulam connection proposed in building design requirements in various countries. Compared to the non-reinforced glulam, the average shear strength of textile glass fiber reinforced glulam was markedly increased. The non-reinforced glulam and the GFRP reinforced glulam underwent a momentary splitting fracture. However, the failure mode of textile glass fiber reinforced glulam showed a good ductility.

• Journal of the Korean Ceramic Society
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• v.40 no.7
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• pp.644-651
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• 2003

Effects of additives on electrical properties and microstructure of MLCC X7R dielectrics have been investigated. The additives of glass frit or oxide form were added in the same main composition by the different powder processing conditions. As a result of the dielectric property and microstructure analysis, the composition having the glass layer with dopant concentration gradient showed the excellent dielectric properties. The MLCCs were fabricated with the excellent composition and all dielectric properties satisfied the X7R requirements.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1120-1122
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• 1999

In the design of vehicle glass antenna system, it is essential to use preamplifier between the glass antenna and the TV set, since glass antenna has low gain. In this paper, the preamplifier has been designed in the frequency range from 50MHz to 900MHz with the gam of 10dB. A negative feedback technique has been employed for the wideband characteristics of the amplifler. A DC block capacitor is also used to obtain flat gain response in the wide frequency range. The experimental result shows 1dB ripple in 9dB gain and 0.5dB ripple in 3dB noise figure. The test results were compared with those of the performed by the EEsof-touchstone.

• Applied Microscopy
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• v.45 no.2
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• pp.44-51
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• 2015

At room temperature, metallic glasses deform inhomogeneously by strain localization into narrow bands as a result of yielding due to an external force. When shear bands are generated during deformation, often nanocrystals form at the shear bands. Experimental results on the deformation of bulk metallic glass in the current study suggest that the occurrence of nanocrystallization at a shear band implies the loading condition that induces deformation is more triaxial in nature than uniaxial. Under a compressive stress state, the geometrical constraint strain imposed by the stress triaxiality plays a crucial role in the deformation-induced nanocrystallization at the shear bands.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.623-631
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• 2003

It is considered that the application of advanced composite materials to the prostheses for the disables is important to improve their bio-mechanical performance. Particularly, energy storing foot prosthesis is mostly important to restore gait ability of the disables with low-extremity amputation since it could provide propulsion at terminal stance enhancing the disables ability to walk long distance even run and jump. Therefore, the energy storing spring of Prosthetic foot keel under cyclic bending moment use mainly of high strength glass fiber reinforced plastic. The main objective of this study was to evaluate the stacking sequence effect using the delamination growth rate(dA$_{D}$/dN) of energy storing spring in glass fiber reinforced plastic under cyclic bending moment. The test results indicated that the shape of delamination zone depends on stacking sequence in GFRP laminates. Delamination area(A$_{D}$) turns out that variable types with the contour increased non-linearly toward the damage zones.nes.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.861-867
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• 2015

The Compact Tension (CT) type test was performed in order to evaluate the fracture toughness performance of glass fiber-reinforced laminated timber. Glass fiber textile and sheet Glass fiber reinforced plastic were used as reinforcement. The reinforced laminated timber was formed by inserting and laminating the reinforcement between laminated woods. Compact tension samples are produced under ASTM D5045. The sample length was determined by taking account of the end distance of 7D, and bolt holes (12 mm, 16 mm, 20 mm) had been made at the end of artificial notches in advance. The fracture toughness load of sheet fiberglass reinforced plastic reinforced laminated timber was increased 33 % in comparison to unreinforced laminated timber while the glass fiber textile reinforced laminated timber was increased 152 %. According to Double Cantilever Beam theory, the stress intensity factor was 1.08~1.38 for sheet glass fiber reinforced plastic reinforced laminated timber and 1.38~1.86 for glass fiber textile reinforced laminated timber, respectively. That was because, for the glass fiber textile reinforced laminated timber, the fiber array direction of glass fiber and laminated wood orthogonal to each other suppressed the split propagation in the wood.