• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.3
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• pp.20-28
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• 2007

The easiest way to see the phenomena of compressor surge is to show the static and dynamic operation characteristic on the map. Its operation zone will be restricted by the surge limit and, static and transient process must have some margin for it. Effect of rotor moment of inertia, air/gas volumes and heat transfer are factors to cause the transition from the static line. In case a large volume such as heat exchanger exists in the system it will exert a substantial influence to dynamic characteristics. In the present paper, influence of air volume bled from the compressor exit on transient process is investigated with an example of an auxiliary power unit micro-turbine engine. Turbine mass, pressure ratio, rotation speed, power and moment are calculated based on mass and work conservation. Result from the present study can give guidance to design the control system. A computer program is developed to calculate the dynamic process using the MathCAD commercial software.

• Journal of the Speleological Society of Korea
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• no.81
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• pp.35-41
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• 2007

According as the industry develops recently, the import and export freight amount is increasing sharply, but physical distribution processing equipment ability had achieved conveyance, surge and setup of physical distribution by human's labor ability. But, inefficiency is indicated in operation of product line and warehouse or physical distribution storage equipment because is ceilinged the processing physical distribution amount and the efficiency in physical distribution processing by these labor ability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.838-844
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• 2015

Latest development of ICT makes building, including houses, factories and public facilities, more intelligent and automatized. It follows that a wide variety of electric and ICT installations are adopted along with micro electronic equipments. Corresponding to such changes, the frequency of lightning increases due to the abnormal climate. The major damage by lightning surge is disconnection and malfunction of facilities. It is necessary, therefore, to make a regulation of inspection and maintenance for lightning protection facilities. This paper deals with main issues of a regulation draft of inspection and maintenance for lightning protection facilities based on IEC 62305

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1281-1286
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• 2012

In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, efficiency and performance of 2.4GHz band which leads to saturation of the communication was significantly fall. in this paper, the U-slot microstrip array antenna in the 5 GHz band have been studied to improve the drawback of a narrow bandwidth of the T-slot micro strip antenna. The characteristics of single antenna and array antenna was investigated to obtain the optimum frequency properties. The optimal U-slot microstrip array antenna possibility was confirmed.

• The Journal of the Petrological Society of Korea
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• v.14 no.4 s.42
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• pp.195-211
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• 2005

The Kusandong Tuff, known as a representative key bed in the Cretaceous Gyeongsang Basin, is a crystal-rich tuff of pyroclastic flow and surge origin. It is 1-4 m thick and laterally extends for more than 200 km intercalated in the upper part of the Hayang Croup. Observations and analyses of the feldspar crystals in the tuff, using polarizing microscopes, EPMA, and BSE images, reveal that the plagioclase crystals in the tuff were completely albitized (>$97\%$ Ab) whereas those in the southernmost localities where the tuff is rich in fine ash matrix are unaltered or partly albitized. K-feldspars are partly albitized at all localities, irrespective of the matrix content of the tuff, Perthitic textures, chessboard twinning, albitization along micro-fractures and cleavages, and the relationship between matrix content and the degree of albitization suggest that feldspars in the Kusandong Tuff were albitized by Na-rich fluid after burial. Albitization is interpreted to start preferentially along micro-fractures and cleavages and be hampered in matrix-rich tuffs with a low permeability. Original composition of the plagioclases in the Kusandong Tuff is also interpreted to have ranged between oligoclase and andesine ($Ab_{62.5}-Ab_{83.3}$) before the albitization.