• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.343-347
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• 2019

When referring to weight, volume, and efficiency, a SuperConducting Synchronous Generator (SCSG) is definitely superior to conventional generators as a large-scale wind power generation system. The SCSG is connected to a full power converter that transmits the energy from the SCSG to the power grid. To reduce the current stress and system cost, the SCSG which has nine-phase armature windings with three converters is used. This paper deals with a comparative analysis of 10 MW superconducting wind power generators with three-phase and nine-phase armature windings. The stator windings of SCSGs are of various types. Using the finite element method, SCSGs are analyzed and compared in terms of the weight and volume of SCSGs, the total length of the superconducting wire, harmonics, torque performance, and efficiency. The analyzed results will be effectively utilized to design large-scale superconducting generators for wind power generation systems.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.75-79
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• 2001

In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dynamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However, the research on dynamic characteristics is very deficient. In this paper, the helical spring are fabricated with NiTi SMA wire of high resistivity, The force, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA is analyzed. Also, bidirectional actuator was fabricated and experimented for its performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.6
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• pp.702-713
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• 1998

The characteristics of flow and particle collection for an electrocyclone with a central wire inside a high efficiency Stairmand cyclone was numerically analysed. Turbulent flow field was modeled by the Reynolds stress model and solved with an FVM code FLUENT. Particle motion and in-situ charging were simultaneously solved by a Lagrangian integration with time. The flow field obtained was in good agreement with experiments in the outer region. The characteristics of collection enhancement due to electric force were well manifested and well explained based on first principles. The effect of the in-situ charging process was very similar to the case of a simplified assumption of saturated charging, and the effect of the hopper was proved negligible.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.2.3-2.3
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• 2011

With increased interest in printed devices, various metal nano inks have been investigated as candidates materials for printed electrodes and wiring as well as conductive film substituting photo-lithography process. Recent advances in organic conductive polymer allow us to fabricate high performance printed device. Meanwhile, there was several attempts to fabricate conductive films by mixing conductive polymer with metal nano-particle or nano-wires. The presence of Ag nanowires in conductive polymer mixture have shown good potential in organic photovoltaic devices.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.767-772
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• 2005

The Internet is a packet switched network which offers best-effort service, but current IP network provide enhanced services such Quality of Services, Virtual Private Network (VPN) services, Distribute Firewall and IP Security Gateways. All such services need packet classification for determining the flow. The problem is performing scalable packet classification at wire speeds even as rule databases increase in size. Therefore, this research offer packet classification algorithm that increase classifier performance when working with enlarge rules database by rearrange rule structure into Bitmap Intersection Lookup (BIL) tables. It will use packet's header field for looking up BIL tables and take the result with intersection operation by logical AND. This approach will use simple algorithm and rule structure, it make classifier have high search speed and fast updates.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.1
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• pp.7-14
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• 2015

Recently, advances in nano-material researches have opened the door for various transparent conductive materials, which include carbon nanotube, graphene, Ag and Cu nanowire, and printable metal grids. Among them, Ag nanowires are particularly interesting to synthesize because bulk Ag exhibits the highest electrical conductivity among all metals. Here we reviewed recently-published research works introducing various devices from organic light emitting diode to tactile sensing devices, all of which are employing AgNW for a conducting material. They proposed methods to enhance the stretchability and reversibility of the transparent electrodes, and apply them to make various flexible and stretchable electronics. It is expected that Ag nanowires are applicable to a wide range of high-performance, low-cost, stretchable electronic devices.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.585-590
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• 1999

The conventional $CO_2$ inverter arc machine has constant voltage output characteristic and uses constant wire speed controller for welding current control. By adoption of PWM inverter to the welding machine, the spattering was reduced rather than the thyrister arc welding machine or AC arc welding machine. Moreover, by the high switching frequency, the output reactor size could be reduced evidently. Recently, the studies on optimal voltage and current waveform for the welding performance improvement have been studied. In this paper, a new instantaneous output current control scheme during the short circuit mode was proposed and showed the capability of arc stability improvement and the reduction of spatter generation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.47-52
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• 2003

In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dynamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However, the research on dynamic characteristics is very deficient. In this paper, the helical spring are fabricated with NiTi SMA wire of high resistivity. The force, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA is analyzed. Also, bidirectional actuator was fabricated and experimented fir its performance.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.3
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• pp.67-72
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• 1992

This paper presents the process of manufacturing technology of ceramics ferrule for opitcal fiber connector. Precision zirconia ceramic ferrules is widely for high performance and low cost single mode optical fiber connectors. To polish the hole of the zirconia ceramic ferrule, the wire lapping instrument is developed and the machining experiment is conducted. Through the centerless grinding using diamond wheel the surface roughness of zirconia ceramics ferrule is below the 1$\mu$m Rmax.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.3026-3032
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• 2000

To enhance the effective data transfer rate the multi-beam optical disk drive is presented. The Beam rotating actuator is necessary for putting multi-beam on more than one track. Ray tracing was also executed for real system set-up. The beam Rotating Actuator is made up of piezoelectric material, high stiffness wire hinge and dove prism. The actuator has about 1kHz natural frequency and suitable operational range. The dynamic equation for the actuator is derived for the control real system.