• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2725-2730
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• 2007

Turbo-type molecular drag pumps ( MDPs ) are used in the liquid crystal display ( LCD ), semiconductor and other thin film industries. Siegbahn ( disk-type ) molecular drag pumps are used as high-pressure stages in the hybrid-type turbomolecular pumps, where they can operate in the viscous, the transition and the free molecular flow regime. In this study is performed to investigate the pumping characteristics of three-stage disk-type molecular drag pump ( DTDP ) in the molecular transition flow region. The experiments are measured using five vacuum pressure gauges in the positions for rotors of DTDP. The test is performed with nitrogen gas ( $N_2$ ).

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.186-192
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• 2000

The heat generated in contact type braking system can cause an unacceptable braking performance. Thermal behavior of ventilated disk brake system is presented in this paper. The temperature and velocity fields of 3-D unsteady simulated model are obtained using a software package "FLUENT". The numerical results show that there exits a temperature nonuniformity between the disk faces contacting with pads. The conduction rate through the disk and pad is calculated and the effect of material conductivity is also investigated.estigated.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.11
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• pp.806-812
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• 1987

The ozone generation characteristics are reported for a sawtooth disk to cylinger geometry using positive and negative pulse corona. A series of parametric studies was carried out to obtain optimum values for the pulse repetition frequency as well as the shape and dimensions of the discharge disk and the discharge spacing. Two types of ozonizers were studied: the single disk and the multi-disk. The results of the single disk ozonizer showed that positive corona produced a singificantly higher ozone yield than negative(7ppm/peak watt or 3.5 times larger). However the negative corona produced a much more controllable output which enabled the ozone generation to be directly controlled by adjusting the value of the peak pulse voltage. This results showed that the single disk ozonizer is ideally suited for applications requiring very small controlled quantities of ozone whereas the multi-disk unit can be designed to provide varying outputs depending upon the number of disk electrodes used.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.655-662
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• 2007

This paper presents a disk-type capacitive sensor for simultaneous measurement of five-dimensional motions of a target. The sensor can be manufactured with a printed circuit board (PCB) such that the sensor can be integrated with its electronics in a single PCB board, whereby the manufacturing costs is considerably reduced. The sensor is optimally designed through an error analysis of possible mechanical errors. Furthermore, the sensor can correct the horizontal motion measurement errors due to the sensor installation tilting error. A proto-type PCB sensor, electronics and a test rig were built, and the effectiveness of the developed sensor was proved through experiments.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.577-580
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• 2002

In this paper, the pumping performance of the disk-type drag pump which works in the outlet pressure range from 4 to 0.001 Torr is studied experimentally. The pumping characteristics of various drag pumps are performed. The inlet pressures are measured for various outlet pressures of the test pump. The flow-meter method is adopted to calculate the pumping speed. Compression ratios and pumping speeds for the nitrogen gas are measured. The present experimental data show the leak-limited value of the compression ratio in the molecular transition region. The rotational speed of the pump is 24,000rpm. The inlet pressures are measured for various outlet pressures of the test pump. The ultimate Pressures for zero throughput are measured for three-stage, two-stage and single-stage disk-type, respectively.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.579-584
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• 2005

Nowadays heat exchangers that have been applied for freon refrigerating systems, a shell and tube type condenser and a flooded evaporator have been used, but because of their large size, large space for installation and amount of refrigerants are needed. In this study, we will find the most suitable operating condition of shell and disk type optimum heat exchanger which can minimize the amount of a refrigerant and allow its minimum leakage. The condensing pressure of refrigeration system is increased from 15.0bar to 16.0bar and degree of superheat is increased from 0 to $10^{\circ}C$ at each condensing pressure. As a result of study, It revealed that shell and disk type heat exchanger was applicable to the freon refrigeration system

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1720-1722
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• 1999

In this paper, we studied the properties of small-size disk-type ultrasonic motor using travelling wave for the application to the precise control robotic joint motor and fabricated it. The diameter of the ultrasonic motor fabricated was 13mm. Also, the piezoelectric vibrator was constructed by piezoelectric ceramic and elastic material. The piezoelectric ceramic was composed to PZ-PT-PMN which was shown the high electromechanical stability under high vibration level and stainless steel was used as the elastic material in which configuration was disk-type. To conform the capability of application to robotic motor, we measured the change of rotational speed according to applied voltage and applied frequency. As the results, the small-size disk-type ultrasonic motor was able to fabricate, and the revolution speed was 350 [rpm] when input voltage was 55 [Vrms] and applied frequency 160.4 [kHz] under pre-load.

• Tribology and Lubricants
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• v.25 no.2
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• pp.102-107
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• 2009

The thermal deformation volume of motorcycle break disk was studied using a disk-on-pad type friction tester. Thermal deformation volume of motorcycle break disk have an effect on the frictional factor such as applied load, sliding speed, sliding distance and number of ventilated disk hole. However, it is difficult to know the mutual relation of these factors on thermal deformation volume. In this study, the thermal deformation volume with ANSYS workbench are obtained by application of temperature from mechanical test. From this study, the result was shown that the motorcycle break disk with ventilated hole 3 have the most excellent thermal deformation characteristics. The regression equation with frictional factors which have a trust rate of 95% for prediction of thermal deformation volume of motorcycle break disk was composed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.200-210
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• 1997

This paper presents the thermal behaviours of a solid type disk brake for a high-speed train. The thermal behaviours of a brake disk with 50mm thickness shows good performance compared with 45mm thickness of a disk because of a high specific heat capacity and thermal expansion ratio. The FEM results show that the thickness of the d!sk with a same weight of the brake disk should be increased for a good flexibility of the contact thermal problems. Therefore, the ratio between the pad and disk in diameter may be reduced and the thickness of a disk increased.

• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.81-85
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• 2007

Reliability of a hard disk drive depends on the head disk interface (HDI) characteristics. Particularly, the disk media and the head can be damaged due to contact between the two components during operation. The contact may occur due to particles being introduced into the disk/slider interface or due to direct contact between the slider and the disk. Such contacts may be induced by external vibration or abnormal operation of the HDI. In this work the characteristics of scratches generated on the disk surface were investigated. The scratches were generated by impacting the hard disk. The type of scratches was analyzed with respect to their shape and dimensions.