• Proceedings of the KIEE Conference
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• summer
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• pp.1121-1123
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• 2004

Characteristics of the break down current of HTS tape with different insulator are described. The various insulators are utilized for enduring the high voltage in superconducting power devices. The break down current of HTS tape largely depends on insulators wound round HTS tape. In this research, The break down currents of Bi-2223 tape, which is widely used for superconducting power devices are tested and discussed. It is expected that results from this study can be utilized as basic data in designing superconducting power devices.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.50-57
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• 2021

Engine cool down process is necessary for the liquid rocket engines using cryogenic propellants in order to meet the requirement of engine inlet temperature. This paper evaluates the cool down characteristics of oxidizer supply pipeline and engine in prechill process prior to the engine firing tests, and calculate the quantity of liquid oxygen consumption.

• Journal of Ocean Engineering and Technology
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• v.16 no.3
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• pp.40-45
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• 2002

In this study, the effects on hydraulic characteristics are discussed as the permeable underlayer thickness of the rubble mound structure changes. A series of hydraulic experiments were performed and wave run-up, reflection and set-up were investigated. Result indicated that wave run-down was affected by the water out from the permeable underlayer during down-rush. As the thickness increased, relative wave run-up decreased.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.599-600
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• 2010

• Textile Coloration and Finishing
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• v.32 no.4
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• pp.232-238
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• 2020

Duck down is a feather of waterfowl and is used as an accessory for bedding products such as evil, pillow and outdoor sleeping bags due to its soft and bulky characteristics. Down is used mainly for winter outdoor such as padding and jumpers because of its excellent thermal insulation effect. Down wear is known as a product with high added value. Down is processed and sanitized because a large amount of oil and fat, bacteria, dust, insects, and soil are mixed. In particular, if the proper amount of oil and fat is not removed, it may cause odor or bacteria, and since the fishy smell peculiar to down and harmful VOCs (toluene, benzene, etc.) are released, there is a need to suppress the occurrence of bacteria through the provision of antibacterial function. In this study, we investigated the substances that cause the fishy odor of down, and confirmed the effect on the deodorization and antibacterial properties of down according to processing agents and processing conditions in order to impart deodorant and antibacterial properties to down.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.2
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• pp.17-24
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• 2004

In end milling process, undeformed chip thickness and cutting forces vary periodically with phase change of the tool. Recently, a model has been proposed to simulate the shear and friction characteristics of an up-end milling process in terms of the equivalent oblique cutting to this. In the current study, a down-end milling process has been replaced with the equivalent oblique cutting process. And shear and tool-chip friction characteristics variation of SM45C steel has been studied using the end-mills of different helix angles. The specific shear and friction energy consumed with helix angle of $50^{\circ}$ is somewhat larger than those of$30^{\circ}$ and $40^{\circ}$. The specific shear energy consumed is about 76-77% of the specific cutting energy regardless the helix angles.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.161-165
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• 2001

End milling is one of the most widely used machining operations. It is associated with productivity and production quality progress. In metal cutting with up and down milling, moment is important factor to diagnose the cutting characteristics because the amount of tool wear directly influences the moment. In this study, the effects of number of milling cutting edges on the cutting performance, especially on the moment, are investigated. The results acquired through the cutting test measuring moment show that up milling is superior to down milling.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1108-1109
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• 2015

In general, when a high-temperature superconducting (HTS) field coil breaks down, the overall field coils of a superconducting synchronous generator (SCSG) are also stopped working, because of the HTS field coils are connected in series. Therefore, the HTS field coils have to be modularized. The modularized HTS field coil is operated individually. Therefore, even if the HTS field coils are broken-down, the generator still operates under the fault conditions. But the output power and torque of the generator will be affected. This paper deals with the fault characteristics analysis of a 12 MW class SCSG with the modularized HTS field coils when the coils were broken-down. The steady-state and transient state characteristics of the modularized 12 MW class SCSG were analyzed and compared. The fault characteristics analysis results of the 12 MW class superconducting generator for the wind turbines were discussed in detail.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.127-129
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• 1994

For scale-down EEPROM, MONOS structures with the different thicknesses of gate insulators, are fabricated and the memory characteristics, such as swtching and retention characteristics are investigated. As a results, the devices with the top oxide of 20A thick were deteriorated in retentivity. However, 11V-programmable voltage for ΔV$\sub$FB/=4V and 10-year data retention were achieved in MONOS structure with the t7p oxide of 50 ${\AA}$ thick and nitride 45${\AA}$thick.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.1
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• pp.128-133
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• 2013

Si Nanowire (Si-NW) arrays were fabricated by top-down method. A relatively simple method is suggested to fabricate suspended silicon nanowire arrays. This method allows for the production of suspended silicon nanowire arrays using anisotropic wet etching and conventional MEMS method of SOI (Silicon-On-Insulator) wafer. The dimensions of the fabricated nanowire arrays with the proposed method were evaluated and their effects on the Field Effect Transistor (FET) characteristics were discussed. Current-voltage (I-V) characteristics of the device with nanowire arrays were measured using a probe station and a semiconductor analyzer. The electrical properties of the device were characterized through leakage current, dielectric property, and threshold voltage. The results implied that the electrical characteristics of the fabricated device show the potential of being ion-selective field effect transistors (ISFETs) sensors.