• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.60.4-60.4
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• 2019

Small bodies in the solar system are pristine leftovers of planetesimals since the formation epoch (~4.6 Gyr ago). After the formation, icy planetesimals have been preserved in the distant cold place beyond 30 au (i.e., Trans-Neptunian region) until recently without any catastrophic processes but have just been injected into inner region (<~5 au from the Sun) to be observed as comets. On the contrary, asteroids are rocky primitive objects (although some of them contains icy volatiles) distributing in the mainbelt between Mars and Jupiter orbits. Because of frequent encounters in the mainbelt, asteroids have experienced a number of repeated impacts until the present day. Namely, it is important to investigate thermal alternation process of cometary volatiles and refractories in the solar radiation field, whereas collisional and subsequence phenomena of asteroidal bodies. Although recent spacecraft observations revealed the physical natures on the surfaces of comets and asteroids, their interiors still remain largely unexplored. It is likely that a sudden brightening of a comet is associated with rapid sublimation of internal CO and CO2 or phase transition of amorphous H2O. An episodic dust ejection from an asteroid is causally related to an impact among asteroids, sudden sublimation of remaining subsurficial volatiles, etc. Because these transient phenomena provide rare opportunities to investigate their interiors, immediate observations using any optical instruments are particular important. In my presentation, I will review some examples of such transient phenomena in the solar system and propose possible collaborative research using the Korean Small Telescope Network.

• Proceedings of the KWS Conference
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• 1997.05a
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• pp.201-202
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• 1997

• Electrical & Electronic Materials
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• v.23 no.8
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• pp.3-9
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• 2010

• Proceedings of the KWS Conference
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• 2000.04a
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• pp.211-214
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• 2000

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.96-98
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• 2002

• Proceedings of the KIEE Conference
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• 1983.07a
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• pp.68-69
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• 1983

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.187.1-187
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• 1999

• Proceedings of the KIEE Conference
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• 2005.07e
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• pp.88-90
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• 2005

There are a lot of troubles during the transfer of the source of electric power in UPS (uninterruptible power supply system) which is indispensable to the industrial equipments. They cause blackout accidents, resulting in a great economic loss. After measuring and analyzing the transient phenomena happening during the transfer, this paper presents the solution of the troubles. The solution can be used as a basic material for maintenance and it can minimize the troubles occurring in UPS and enhance the reliability of it.

• Journal of Power Electronics
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• v.7 no.2
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• pp.89-96
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• 2007

This paper deals with the transient performance of an induction generator in a wind power plant. An induction generator and grid equipment may be damaged when a sudden disturbance occurs, for example, a sudden disconnection from the utility grid. The reasons for this are over-voltage and over speed. This paper analyzes this phenomena using PSCAD/EMTDC and coincides with its corresponding mathematical equation.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.173-181
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• 2005

A fluid transient analysis for the propellant flow in a monopropellant propulsion system is conducted using the method of characteristics (MOC). Algebraic simultaneous equations method and Clamor's rule method utilized to drive the compatible and characteristic equations are reviewed to understand MOC more extensively. The identification of fluid transient phenomena of propulsion system of Koreasat 1 is carried out through parametric studies. Also this work describes the reason that the propulsion system of Koreasat 1 has no orifice to control flow transients or to limit the initial hydrazine flow rate for the first-pulse firing.