• 제목/요약/키워드: Sprayed

검색결과 1,366건 처리시간 0.027초

Plasma Spray Forming 공정에 의해 제조된 텅스텐 성형체의 미세조직 형성 거동 (Microstructural Evolution of Thick Tungsten Deposit Manufactured by Atmospheric Plasma Spray Forming Route)

  • 임주현;백경호
    • 한국분말재료학회지
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    • 제16권6호
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    • pp.403-409
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    • 2009
  • Plasma spray forming is recently explored as a near-net-shape fabrication route for ultra-high temperature metals and ceramics. In this study, monolithic tungsten has been produced using an atmospheric plasma spray forming and subsequent high temperature sintering. The spray-formed tungsten preform from different processing parameters has been evaluated in terms of metallurgical aspects, such as density, oxygen content and hardness. A well-defined lamellae structure was formed in the as-sprayed deposit by spreading of completely molten droplets, with incorporating small amounts of unmelted/partially-melted particles. Plasma sprayed tungsten deposit had 84-87% theoretical density and 0.2-0.3 wt.% oxygen content. Subsequent sintering at 2500$^{\circ}C$ promoted the formation of equiaxed grain structure and the production of dense preform up to 98% theoretical density.

Algorithms to measure carbonation depth in concrete structures sprayed with a phenolphthalein solution

  • Ruiz, Christian C.;Caballero, Jose L.;Martinez, Juan H.;Aperador, Willian A.
    • Advances in concrete construction
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    • 제9권3호
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    • pp.257-265
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    • 2020
  • Many failures of concrete structures are related to steel corrosion. For this reason, it is important to recognize how the carbonation can affect the durability of reinforced concrete structures. The repeatability of the carbonation depth measure in a specimen of concrete sprayed with a phenolphthalein solution is consistently low whereby it is necessary to have an impartial method to measure the carbonation depth. This study presents two automatic algorithms to detect the non-carbonated zone in concrete specimens. The first algorithm is based solely on digital processing image (DPI), mainly morphological and threshold techniques. The second algorithm is based on artificial intelligence, more specifically on an array of Kohonen networks, but also using some DPI techniques to refine the results. Moreover, another algorithm was developed with the purpose of measure the carbonation depth from the image obtained previously.

2-Chloroethyl Phosphonic Acid가 잎담배 조열에 미치는 영향 (Accelerating Effect of 2-Chloroethyl Phosphonic Acid Foliar Applications on Leaf Tobacco Maturity)

  • 곽병화
    • Journal of Plant Biology
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    • 제15권2호
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    • pp.1-6
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    • 1972
  • Cultivar Yeollow Special A, the most leading Korean economic leaf tobacco in Korea, were field-cultivated in four different localities of Korea for the period of two years (1970 and 1971) and sprayed at varied levels of 2-chloroethyl phosphonic acid (CEPA) for foliar application few days after topping. While no striking difference in leaf yield by weight was obtained among the treatments when compared with control, leaf quality as expressed for shipment price in won tended when compared with control, leaf quality as expressed for shipment price in won tended to improve. The treated leaves with 300 to 900 ppm of CEPA (approximately 140 1/acre of 500 ppm) not only showed yellowing and accelerated maturity to pick 4 to 5 days with practicable optimal level earlier than control, but also speeded up to take nearly with practicable optimal level earlier than control, but also speeded up to take nearly last half of the total time required for the five stages of flue-curing. It is therefore considered that CEPA is as effective maturity-accelerating agent and useful as known for other solanaceous plants showing climacteric stage respiration, and discussions were made about physiological actions of ethylene gas released from CEPA at plant tissues sprayed.

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플라즈마용사 세라믹코팅 피막부식재의 음향방출 특성 (Acoustic Emission Characteristics of Plasma Sprayed Ceramic Coating Layer after Salt Spray)

  • 김귀식;박경석;홍용의
    • 한국해양공학회지
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    • 제15권3호
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    • pp.69-74
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    • 2001
  • This paper was to investigate of a adhesiveness for the plasma sprayed coating materials did salt spray by acoustic emission method in tensile loadings. The powders used for the coating were nickel aluminum composite powder Ni-4.5wt.%Al and titanium dioxide powder $TiO_2$. These powders were coated on a carbon steel S45C by plasma spray method. The result solution was a 5% NaCl and the slat spray times were 2, 5 and 10 hours respectively. The salt solution penetrated into the surface of the substrate through pore of the coating layer built in the process of plasma spay. Corrosion productions formed on the surface of substrate. The adhesiveness between the substrate and the coating layer is weaken by corrosion and the exfoliation initiated chiefly at the corrosion surface of the substrate. The AE events and energy of the corroded coating specimens decreased as the salt spray times increased.

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