• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.5
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• pp.324-329
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• 2018

Red phosphor in glasses (PiGs) for automotive light-emitting diode (LED) applications were fabricated with 620-nm $CaAlSiN_3:Eu^{2+}$ phosphor and Pb-free silicate glass. PiGs were synthesized and mounted on high-power blue LED to make a monochromatic red LED. PiGs were simple mixtures of red phosphor and transparent glass powder. After being fabricated with uniaxial press and CIP at 300 MPa for 20 min, the green bodies were thermally treated at $550^{\circ}C$ for 30 min to produce high dense PiGs. As the phosphor content increased, the density of the sintered body decreased and PiGs containing 30% phosphor had a full sintered density. Changes in photoluminescence spectra and color coordination were studied by varying the thickness of plates that were mounted after optical polishing. As a result of the optical spectrum and color coordinates, PiG plate with $210{\mu}m$ thickness showed a color purity of 99.7%. In order to evaluate the thermal stability, the thermal quenching characteristics were measured at temperatures of $30{\sim}150^{\circ}C$. The results showed that the red PIG plates were 30% more thermally stable compared to the AlGaInP red chip.

• Journal of Mechanical Science and Technology
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• v.15 no.10
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• pp.1380-1385
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• 2001

This paper evaluates the fatigue fracture behavior of a chopped strand glass mat/polyester composite both in ai, and sea water, Bending fatigue (R=-1) was performed on dry and wet specimens, that is respectively in air and sea water. Where the pH concentration of sea water was controlled to 6.0,8.2, 10.0 and the wet specimens were immersed in the sea waters for 4 months. Throughout the tests, fatigue cracks both in the dry and wet specimens, tested in the air or sea water, occurred at the beginning of the cycle, followed by either of two regions one decreasing and the other increasing as the crack growth rate increases.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.82.1-82.1
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• 2000

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.20-26
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• 2013

In this paper, we propose a multi-band monopole antenna with a band-notching U-slot, which is fabricated inside the flexible polymide film substrate. The U-shaped slot located on the patch-shaped monopole antenna provides band-notch at 2.7 GHz, but also helps to improve return loss at adjacent frequency bands. The performance of the antenna attached on an automobile-glass has been simulated and measured. The fabricated antenna provides more than 10 dB return loss for ISM band(2.4~2.483 GHz) and WAVE band(5.85~5.925 GHz), 2.8~5.7 dBi maximum gain, and good radiation patterns.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.8
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• pp.60-66
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• 2021

This study aimed at identifying and optimizing the heating-condition parameters that cause surface defects during the compression molding of chalcogenide glass (GeSbSe) lenses through thermal analysis. We derived the optimal heating conditions for molding chalcogenide glass lenses through thermal analysis and analyzed the surface defects. As a result, we observed a significant reduction in surface defects, which verified the analysis process.

• Polymer(Korea)
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• v.25 no.3
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• pp.427-434
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• 2001

The sound absorption materials With polyester (PET) were prepared for automobile. They consist of 3 layers with different size of PET fiber (3 and 15 deniers) in order to optimize the characteristic of sound absorption, and with various densities (895~1790 g/$cm^2$) by controlling the weight of PET of each layer. They were also compared with the commercial sound absorption materials made of glass wool. It was shown that the new PET had better absorption capability in both high and low frequency regions than that of the commercial material. It was revealed also that the density and the thickness of PET played an important role to determine the capability of sound absorption. The NRC (noise reduction coefficient) was increased by 22-39% with optimized PET sound absorption material. It should be noted that the PET can substitute the glass wool, a commercial sound absorption material, in view of environment and as well as recycle capability of sound absorption.

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.663-669
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• 1999

Ag thick film conductors were fabricated with Ag powders having different degree of dispersion and glasses having different viscosity, and then the relationship between microstructure and electrical properties of the Ag films was investigated. Under the same processing condition. the Ag thick film that was prepared with the well-dispersed Ag powder and glass having low viscosity had denser microstructure and lower resistance than those of the film which was fabricated with the agglomerated Ag powder and glass having high viscosity It is believed to be due to the fast micro rearrangement kinetics when the well dispersed Ag powder was used, and all the microstructure development kinetics were impeded when low viscosity glass used. It was found that theme fast microstructure development kinetics resulted in the dense microstructure and the lower sheet resistance of the films. Also, the saturation time, at which at a given temperature no further decrease in the sheet resistance was obtained, was found to be shortened when well-dispersed Ag powder and low viscosity glass were used.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.1
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• pp.27-32
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• 2002

In this study, estimate of Mechanical Properties depending on Injected direction in Polymer for Automobile Application. The used materials is polyamid(nylon6), polypropylene(PP) of a simple component and its mixed, reinforced glass fiber(15%) in polyamid. One side direction of a simple component is highest strength and the two sides direction of multicomponent appear lowest strength. This is caused by effects of weldline, imperfect fusion and impregnation of multicomponent. To improve mechanical properties, it is necessary to minimize of weldline, compatibility, perfect fusion and impregnation in multicomponent polymer.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.157-163
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• 2003

This work was undertaken for the numerical analysis of defrosting phenomena of automobile windshield. To analyze the defrost, the flow and temperature field of cabin interior, heat transfer through the windshield glass, and phase change of the frost should be analyzed simultaneously. The flow field was obtained by solving the 3-D unsteady Navier-Stokes equation and the temperature field was computed by energy equation. The phase-change process of Stefan problem was solved by enthalpy method. For code validation, the temperature field of the driven cavity was calculated. The result of calculation shows a good agreement with the other numerical results. Then, the present code was applied to the defrosting analysis of a real automobile and, also, a good agreement with experiment was obtained.

• Textile Coloration and Finishing
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• v.27 no.3
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• pp.165-174
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• 2015

To develop automobile parts, the unsaturated polyester based matrix resin(PR)/reinforcement(randomly oriented chopped E-glass fiber, GF) composites were prepared using sheet molding compound(SMC) compression molding. The effects of GF length(0.5, 1.0 1.5 and 2.0inch)/content (15, 20, 25, 30wt%) and number of ply(3, 4 and 5) on the specific gravity and mechanical properties of PR/GF composites were investigated in this study. The optimum length of GF was found to be about 1.0inch for achieving improved mechanical properties(tensile strength and initial modulus). The tensile strength and initial modulus of composites increased with increasing GF content up to 30wt%, which is favorable content range for SMC. The specific gravity, tensile strength/initial modulus, compressive strength/modulus, flexural strength/modulus and shear strength increased with increasing the number of ply up to 5, which is the maximum number of ply range for SMC. The effectiveness of ply number increased in the flexural strength > shear strength > compressive strength > tensile strength.