http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
노즐 축소부 수렴각이 고속 광섬유 피복유동에 미치는 영향
박신(S. Park),김경진(K. Kim),곽호상(H.S. Kwak) 한국전산유체공학회 2016 한국전산유체공학회지 Vol.21 No.4
A numerical study is conducted on the optical fiber coating flow in a primary coating nozzle consisting of three major parts: a resin chamber, a contraction and a coating die of small diameter. The flow is driven by the optical fiber penetrating the center of the nozzle at a high speed. The axisymmetric two-dimensional flow and heat transfer induced by viscous heating are examined based on the laminar flow assumption. Numerical experiments are performed with varying the convergent angle of nozzle contraction and the optical fiber drawing speed. The numerical results show that for high drawing speed greater than 30 m/s, there is a transition in the essential flow features depending on the convergent angle. For a large convergent angle greater than 30°, unfavorable multicellular flow structures are monitored, which could be associated with wall boundary-layer separation. In the regime of small convergent angle, as the angle increases, the highest resin temperature at the exit of die and the coating thickness decrease but the sensitivity of coating thickness on drawing speed and the maximum shear strain of resin on the optical fiber increase. The effects of the convergent angle are discussed in view of compromise searching for an appropriate angle for high-speed optical fiber coating.
국내외 당근 품종의 carotene과 당의 성분량 비교
박용,박신,류장발,박상규 大邱大學校 科學技術硏究所 1997 科學技術硏究 Vol.4 No.3
Carotene and sugar contents of 36 commercial carrot cultivars were investigated as a preliminary study for the breeding of high carotene and sugar contents. Big differences in carotene content among cultivars were observed(80.2-184.5ppm), and many cultivars developed by Belo company in Netherland contain higher amount of carotene than others while a Korean cultivar contains relatively low amount of carotene. Although sugar content did not show big differences among cultivars, the Korean cultivar contains relatively low content.