• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1639-1644
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• 2015

Auxiliary air compressor(ACM) applied to railroad cars is a device which controls amount of compressed air in order that pantographs can be mounted correctly on the roof of an electric train. Existing ACMs consist of dc motors and brushes wear out due to friction with a commutator. Therefore, continuous maintenance is required. However, three phase BLDC motors have higher power density compared to dc motors and the machine maintenance is not needed because electric commutation is possible. The three phase generally uses hall sensors to get position information and this enables the accurate control. This paper suggests an algorithm that compensates the errors occurred when the hall sensors have a breakdown for stable operation.

• Journal of the Korean association of regional geographers
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• v.21 no.3
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• pp.608-617
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• 2015

This paper synthetically analyzes micrometeorological data and geomorphological features of Doeksan-ri Eoreumgol(ice valley) Yeongdeok-gun in order to investigate occurrence characteristics of the ice valley and a mechanism for freezing in summer. This ice valley is located in the distal end of a talus and intensity of cooling and freezing in summer seems to be related to morphology and dimensions of talus. Cooling in the ice valley is generated by cold air flows that move down to the bottom of talus from high mountains through pores and voids, then debris in talus is supercooled by the cold air. For it forms a stable state in and around voids cold air is stagnating in the lower end of talus. This causes freezing in summer at outpour points. Furthermore humidity condition of external air and vaporization heat is a key factor when freezing.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.93.1-93.1
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• 2005

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.201-210
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• 1999

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.175-176
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• 2006

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.140-140
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• 2012

• Proceedings of the SAREK Conference
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• 2005.06a
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• pp.150-150
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.588-589
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• 2008

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.6
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• pp.893-900
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• 2014

The aim of this study was to investigate physicochemical changes in Salvia plebeia R. Br. (SPA) upon hot-air drying and blanching. After hot-air drying and blanching, total polyphenol and flavonoid contents were reduced from 96.64 mg and 48.40 mg gallic acid equivalent/g to 29.70 mg and 22.10 mg quercetin equivalent/g, respectively. DPPH radical scavenging activities at $25{\mu}g/mL$ of SPA were 94.5% for ascorbic acid, 84.3% for hot-air dried SPA, and 59.7% for blanched SPA and there was no significant difference between those of hot-air dried SPA and ascorbic acid as a positive control. Total sugar contents were 7.187% and 6.104% for hot-air dried SPA and blanched SPA, respectively. During the blanching process, sucrose and maltose contents decreased, whereas glucose and fructose contents increased. Glucose and fructose were converted into citric acid in blanched SPA, whereas sucrose and maltose were converted into tartaric acid, malic acid, and succinic acid. Fourteen kinds of amino acids were found, but methionine, lysine, glycine, histidine, and cysteine were absent. The proportion of essential amino acids was 61.76% upon hot-air drying, which was a relatively high amount. In addition, hot-air drying resulted in 1.40 mg/100 g of norvaline as well as 39.00 mg/100 g of GABA, which are non-amino acids. Therefore, Salvia plebeia R. Br. can be used not only as vegetables but also as highly useful and various health functional foods with antioxidant effects and excellent nutrition.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.705-708
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• 2014

We demonstrate the blue InGaN/GaN multiple quantum wells light-emitting diodes (LEDs) with an embedded air-gap photonic crystal (PC) which was fabricated by the lateral epitaxial overgrowth of GaN layer on the tungsten (W) nano-masks. The periodic air-gap PC was formed by the chemical reaction of hydrogen with GaN on the W nano-mask. The optical output power of LEDs with an air-gap PC was increased by 26% compared to LEDs without an air-gap PC. The enhanced optical output power was attributed to the improvement in internal quantum efficiency and light extraction efficiency by the air-gap PC embedded in GaN layer.