• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.796-799
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• 2002

The stress of the rotating disc with several types of hole was investigated in detail in this paper. Maximum circumferential stress of rotating disc by changing hole shape with same area, were studied using FEM. The results obtained were as follows: 1. The disc which rotates at high speed is subjected to circumferential stress remarkably. 2. When the number of circular holes in rotating disc is four, stress reduction effect is maximum. 3. When shape of holes in rotating disc is cylindrical elongated hole, maximum circumferential stress of the rotating disc decreased most.

• Transactions of the Society of Information Storage Systems
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• v.6 no.2
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• pp.57-62
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• 2010

This paper measured and analyzed the source of total power loss of an ODD of a notebook computer. It shows that the biggest power loss is the windage loss due to the friction between rotating disk and surrounding air. It measured the power loss by the tilting motion of a rotating disc which is originated from the unbalanced mass of the rotating disc or the squareness between case-rotor and shaft. The power loss of rotating disc due to tilting motion was also calculated by using FLUENT, and it was correlated with the measured one. This paper shows that the one of the effective methods to reduce the power loss of an ODD is to reduce the tilting motion of a rotating disc.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.3055-3062
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• 1993

The objective of this paper is to obtain stress intensity factor solutions for a corner crack originating at bolt holes in a rotating disc. Initially two-dimensional finite element analyses of a rotating disc with bolt holes are performed to determine the maximum stress region. Subsequently three-dimensional finite element analyses of a rotating disc with a corner crack originating at the bolt holes are performed with a variety of crack geometries. According to the numerical results, the maximum stress intensity factor, with an increase in crack depth ratio, was observed at the surface of the plate due to the interference effect of corner crack and disc bore.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.3
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• pp.65-71
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• 2007

For chip-stack package applications, Cu filling characteristics into trench vias of $75{\sim}10\;{\mu}m$ width and 3 mm length were investigated with variations of the electroplating current density and the speed of a rotating disc electrode (RDE). Cu filling characteristics into trench vias were improved with increasing the RDE speed. There was a Nernst relationship between half width of trench vias of Cu filling ratio higher than 95% and the minimum RDE speed, and the half width of trenches with 95% Cu filling ratio was linearly proportional to the reciprocal of root of the minimum RED speed.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.83-88
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• 2000

multi-beam optical drive is a method to improve the data transfer rate for the optical disc systems by parallel recording and reading on neighboring multi-tracks. In this paper, the beam rotating actuator, which is necessary for the multi-bean optical disc drive to from beam spots on multi-tracks simultaneously, has been developed. The Voice Coil Motor is used as a drive mechanism for high resolution and small size of the actuator. And rotating guide based on link structure is designed for frictionless and axisless rotation of rotating part including dove prism and for rotating in axis of geometric center of dove prism. The characteristics of the actuator are experimented by laser vibrometer, Polytec OFV1102 and a dynamic analyzer, HP35670A. It shows that the actuator has good linearity, rotating range $\pm0.34^\circ$, minimum rotating angle $0.0066^\circ$and natural frequency 113.9Hz. Therefore the actuator can be applied in a multi-beam optical disc system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.991-997
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• 2003

A flow field around a disc in an optical disc drive is invested using numerical methods. The high-speed rotating disc induces a strong flow field around the disc, which causes the pressure distribution on the surfaces of the disc. The pressure difference between the upper and the lower surfaces causes the deformation of the disc. In the first part of this study, flow fields around a rotating disc and a stationary wall are investigated using a similarity solution method, in order to identify the effect of the distance between the disc and the wall on the pressure distribution on the surfaces of the disc. In the second part, flow field in a slim-type optical disc drive is studied using a commercial code in order to consider the effect of the vortices generated by the local geometry of the drive.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.574-578
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• 2003

The objective of this paper is to decide optimal location of pin-hole to minimize stress concenstation around hole in rotating disc. The focus of this investigation is to evaluate the effect of pin-hole for stress distribution around hole using optimum design technic and finite element analysis. Design variables are radial and angular location of pin-hole from center of hole, objective function is maximum stress around hole in rotating disc. We use first order method of optimization technic.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.6
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• pp.131-138
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• 2004

The objective of this paper is to decide optimal location of a pin-hole to minimize stress concentration around the hole in a rotating disc. The focus of this investigation is to evaluate the effect of pin-hole on stress distribution around the hole using optimum design technique and finite element analysis. Design variables are the radial and the angular location of pin-hole from center of the hole and objective function is the maximum stress around hole in a rotating disc. Using first order method of optimization technique, we found that the maximum equivalent stress around the hole with optimized pin-hole could be reduced by 15.1% compared to that without pin-hole.

• Journal of KSNVE
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• v.10 no.5
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• pp.865-872
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• 2000

This paper presents the modeling, theoretical formulation, and stability analysis for a combined system of a spinning disc and a head that contacts the disc. In the analytic model, head interference is considered by a rotating mass-spring-damper system together with a frictional follower force on the damped annular discs. The multiple scale method is utilized to perform the stability system that shows the existence of instability associated with parametric resonances. Using the formulated system , instability regions of optical recording disc are investigated with variation of mass, stiffness and friction force of a head, respectively. The simulation results show that the stiffness of a head is the most sensitive parameter on the instability of the disc.

• 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.