• Korean Journal of Radiology
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• v.25 no.2
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• pp.210-211
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• 2024

• Transactions of the Society of Information Storage Systems
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• v.2 no.3
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• pp.178-183
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• 2006

A Blu-ray disc, which has a more than 25GB optical capacity, has been known as a promising next-generation optical disc format. It commonly has a 1.1 mm thick substrate and a 0.1 mm thick cover layer for beam transmitting and the protection of the reflecting surface. The cover layer is generally formed by the spin coating process. However, in conventional spin coating, small bumps are formed along the rim of the disc, which results in the fatal reading error. Numerical simulation of the thin film flow behaviors during spin coating with the commercial solver and optimal spinning conditions was obtained. Thickness distribution of the cover layer according to the variation of substrate's edge shape could be calculated as well. By modifying the shape of the substrate edge shape, the bumps along the disc rim could be minimized, and it was proved that the chamfered edge, around $5{\sim}10$ degree, is the simplest and most effective way to minimize the bumps.

• Journal of Environmental Health Sciences
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• v.21 no.4
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• pp.49-55
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• 1995

Dyes are released into the environment as industrial wasterwater. Dyes are considered to be a pollution problem because of the wide spread into environment with a variety of colors. Continuous biodegradation of reactive dyes such as Rifacion Red H-3EB, Rifazol Blue BT, Rifacion Yellow P4G and Rifacion Brown RT were demonstrated using multistage rotating disc contactor immobilized by Aspergillus sojae B-10. Aspergillus sojae B-10 was cultivated the optimal medium containing 2.0% glucose, 0.08% $NaNO_3$, 0.1% $KH_2PO_4$ and 0.5% $MgSO_4\cdot 7H_2O$, pH 5 at 32$\circ$C. Mycelium of Aspergillus sojae B-10 were guck to the rotating disc for 10 days until steady state. For continuous biodegradation of reactive dyes by using rotating disc contactor, it was most effective biodegradation in the medium containing 1,000 ppm each dyes at the medium feeding rate of 20 ml per hour. Under the conditions biodegradation of each dyes on 2, 4 and 6 days were 20~50%, 75% and 96%, respectively. Therefore, practical application of reactive dyes were carried out at the feeding rate of 20 ml/h as synthetic wasterwater containing 500 ppm of mixture reactive dyes. It was found the highest levels of 94% biodegradation during 20 days.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1621-1626
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• 2003

This study deals with the heat transfer analysis on phase change optical disc with land/groove recording by means of numerical method. Finite difference time domain(FDTD) method was used to obtain the amount of absorption of light propagating inside disc and finite difference element(FEM) method was used to calculate the temperature distribution. The calculated results present the detailed information of recording characteristics on the phase change optical disc. The temperature profiles are quite different between the land track and the groove track. The recorded mark shape on land track is smaller and more elliptic than that on groove track. It is shown that the thermal problem to the neighboring track takes place due to secondary peaks. It is found that the different write strategy should be applied to land and groove recording, respectively.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.219-225
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• 2000

This study is to develop a Fe-based disc brake lining with sponge structure for rolling stock of 150km/h train and to concept design with 3 groove type for brake disc reducing hot hair-crack and certainly friction coefficient. The developing brake lining would be to presumption of saving 300 million won during one year

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.363-364
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• 2007

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.104-111
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• 2006

A ventilated disc brake having spirally fluted surface has been proposed to improve the thermal judder by way of heat transfer enhancement. The local heat transfer coefficients were measured in the flow passage of disc brake. These measured local heat transfer data were utilized to do the finite element numerical analysis which predicts the maximum temperatures on the disc brake. The results show that the maximum temperatures on the disc surface with spirally fluted surface are approximately 26.6% lower than those without them.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1155-1156
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• 2012

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.580-585
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• 2003

Korean high speed train (KHST) has adopted a combined electric/ mechanic (friction) braking system. Electric brakes are consist of rheostatic brake, regenerative brake and eddy current brake and mechanical brakes are composed of disc brake, wheel disc brake and tread brake. In this paper, we introduce the braking performance test and the measuring method of mechanical brake. And disc brake performance has been reviewed by the experimental method. The on-line test of KHST has been carried out up to 260 km/h and proved that the disc braking capacity of KHST is sufficient.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1255-1256
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• 2011