• Title/Summary/Keyword: Vacuum Characteristics

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Combustion Characteristics of Fire Retardants Treated Domestic Wood (난연처리 국산 침엽수재의 연소특성 분석)

  • Seo, Hyun Jeong;Hwang, Wuk;Lee, Min Chul
    • Journal of the Korean Society of Combustion
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    • v.22 no.2
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    • pp.9-18
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    • 2017
  • In this study, we measured that fire characteristics of four wood species using indoor finish materials. Wooden specimens were treated with fire retardant chemicals such as diammonium phosphate and potassium carbonate. The wooden specimens are Larix kaempferi, Pinus koraiensis, Cryptomeria japonica, and Chamaecyparis obtusa, which are used for indoor finish. The heat release rate (HRR) values of fire retardant treated woods were confirmed lower than that of untreated woods. For specific details, the HRR values of vacuum impregnated specimens for Pinus koraiensis and Cryptomeria japonica were measured lower than coatings. However, those of Larix kaempferi and Chamaecyparis obtusa showed the opposite effect to it. Total heat release rate values of all wooden specimens, vacuum impregnated were lower than coated specimens.

Electrical Characteristics of Flat Cesium Antimonide Photocathode Emitters in Panel Devices

  • Jeong, Hyo-Soo
    • Transactions on Electrical and Electronic Materials
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    • v.17 no.5
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    • pp.306-309
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    • 2016
  • The Cs3Sb photocathode was formed by non-vacuum process technology. An in-situ vacuum device was fabricated successively with flat cesium antimonide photocathode emitters fabricated in a process chamber. The electrical properties of the device were characterized. Electron emission from the devices was induced by photoemitted electrons, which were accelerated by an anode electric field that was shielded from the photoemitter surface. The electrical characteristics of the devices were investigated by measuring the anode current as a function of device operation times with respect to applied anode voltages. Planar blue LED light with a 450 nm wavelength was used as an excitation source. The results showed that the cesium antimonide photocathode emitter has the potential of long lifetime with stable electron emission characteristics in panel devices. These features demonstrate that the cesium antimony photocathodes produced by non-vacuum processing technology is suitable for flat cathodes in panel device applications.

Comparative Investigation on the Light Emitting Characteristics of OLED Devices with a Single Layer of Alq3 and a Double Layer of Rubrene/Alq3

  • Jeong, Geon-Su;Lee, Bung-Ju;Kim, Hui-Seong;;Sin, Baek-Gyun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.246.2-246.2
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    • 2014
  • Green-light emitting OLED with single layer of Alq3 and orange-light emitting OLED with double layer of rubrene/Alq3 as EML were fabricated and characterized comparatively. The two OLED devices were based on an anode of ITO, HTL of TPD, and cathode of Al, respectively. The green light emitting OLED was then prepared with Alq3 as both ETL and EML, while the orange-light emitting OLED was prepared with rubrene deposited on Alq3. All the component layers of the OLED devices were deposited by a thermal evaporation technique in vacuum. Photoluminescence characteristics of the EML layers were investigated. Electrolumiscence characteristics of the OLED devices were comparatively investigated.

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Exhaust Noise Reduction of Dry Vacuum Pump (건식 진공 펌프의 배기 소음 저감)

  • Ahn, Young-Chan;Lee, Hae-Jin;Park, Sang-Gil;Lee, You-Yub;Oh, Jae-Eung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.10
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    • pp.950-957
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    • 2007
  • This paper considers acoustic characteristics of silencer within a dry vacuum pump. The main objective is to reduce noise in dry vacuum pump using the new designed silencer. First, SPL and sound intensity are measured for noise source identification and the new model silencer is designed corresponding to noise characteristics. 4-pole parameters are used to predict the transmission loss which is one of the interest characteristics of the new silencer. The calculated transmission loss is then used to change main effective factor and optimal value is selected by using design of experiment. By conducting an experiment, it is proved that the new designed silencer has reduced noise level by 6 dB(A) more than the original one.

Vacuum Characteristics of KSTAR ICRF Antenna during RF Operation (고주파 인가시의 KSTAR ICRF 안테나의 진공특성)

  • Bae, Young-Dug;Kwak, Jong-Gu;Hong, Bong-Geon
    • Journal of the Korean Vacuum Society
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    • v.15 no.3
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    • pp.314-324
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    • 2006
  • The vacuum characteristics of the KSTAR ICRF antenna were experimentally investigated. The fabricated antenna was installed in the RF Test Chamber(RFTC) which has a vacuum system with an effective pumping speed of 1015 l/s. The time variations of RFTC pressure, total gas load and ultimate pressure were measured before the RF test. RF conditioning effect was studied by repeating RF pulses at low power level. A time variation of the RFTC pressure was measured during a RF power was applied to the antenna. Threshold pressure at which a RF breakdown occurs was investigated. Whenever the pressure was higher than $10^{-4}$ mbar, the RF breakdown occurred. During a long pulse testing, the temperature of the antenna and RFTC pressure were measured to investigate long pulse limitation of the maximum available voltage without any cooling, which were compared with testing results with a water cooling of the antenna.