• 제목/요약/키워드: Transfer Factors

검색결과 1,664건 처리시간 0.031초

거칠기 형상이 마찰 계수와 열전달에 미치는 영향 (Effects of Rib Geometries on the Friction Factors and Heat Transfer in the Channel)

  • 안수환;손강필
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2001년도 추계학술대회논문집B
    • /
    • pp.241-247
    • /
    • 2001
  • A comparison of fully developed heat transfer and friction factor characteristics has been made in rectangular ducts with ones roughened by five different shapes. The effects of rib shape geometries and Reynolds number are examined. The rib height-to-duct hydraulic diameter, pitch-to-height ratio, and aspect ratio of channel width to height are fixed at e/De=0.0476, P/e=8, and W/H=2.33, respectively. To understand the mechanisms of the heat transfer enhancements, the measurements of the friction factors are also conducted in the smooth and rough channels. The data indicates that the triangular type rib has a substantially higher heat transfer performance than any other ones in the range we studied.

  • PDF

Factors Affecting the Development of Embryos Produced by Nuclear Transfer

  • Lee, Joon-Hee;Campbell, Keith H.S.
    • 한국수정란이식학회지
    • /
    • 제27권4호
    • /
    • pp.193-203
    • /
    • 2012
  • The development of embryos reconstructed by nuclear transfer is dependent upon numerous factors including the type of recipient cell, method of enucleation, the type of donor cell, method of reconstruction, activation, the cell cycle stage of both the donor nucleus and the recipient cytoplasm and the method of culture of the reconstructed embryos. Many of these points which have been reviewed extensively elsewhere (Sun and Moor, 1995; Colman, 1999; Oback and Wells, 2002; Renard et al., 2002; Galli et al., 2003b), here we will concentrate on main area, the production of suitable cytoplast and nuclear donor, nuclear-cytoplasmic coordination, oocyte activation, culture of reconstructed embryos, and the effects that this may have on development.

사각 덕트에서 거칠기 형상이 마찰계수와 열전달에 미치는 효과 (Effects of Rib Shapes on the Friction Factors and Heat Transfer in a Rectangular Duct)

  • 안수환;손강필
    • 설비공학논문집
    • /
    • 제13권5호
    • /
    • pp.341-347
    • /
    • 2001
  • A comparison of fully developed heat transfer and friction factor characteristics has been made in rectangular ducts with ones roughened by five different shapes. The effects of rib shape geometries and Reynolds number are examined. The rib height-to-duct hydraulic diameter, pitch-to height ratio, and aspect ratio of channel width to height are fixed at $e$/De=0.0476, P/$e$=8, and W/H=2.33, respectively. To understand the mechanisms of the heat transfer enhancements, the measurements of the friction factors are also conducted in the smooth and rough channels. The data indicates that the triangular type rib has a substantially higher heat transfer performance than any other ones in the range we studied.

  • PDF

유동입자층에서의 복사열전달 특성에 관한 연구 (A Study on the Radiative Heat Transfer Characteristics in the Fluidized Particles Layer)

  • 김금무;김용모;김경근
    • Journal of Advanced Marine Engineering and Technology
    • /
    • 제18권4호
    • /
    • pp.33-42
    • /
    • 1994
  • The radiative heat transfer analysis in the fluidized particles layer has important application in many technological areas such as combustion chambers at high pressure and temperature, plasma generators for nuclear fusion, MHD generator using pulverized coal and the liquid droplet radiator used to reject wasted heat from a power plant operating in space. To accurately model the radiation properties of the fluidized particles layer, it is necessary to know the radiation interchange factors of particles in each layer. But the solutions are usually not possible for the equations of radiative heat transfer because it has an inherent difficulty in treating the governing intergo- differential equations, which are derived from the remote effects of radiative heat transfer. In this study, the analysis uses the Monte Carlo simulation method with optical depth model to calculate the radiation interchange factors of particles in each layer with wall and with each other.

  • PDF

Determinants of Technology Transfer and Commercialization in National Research and Development: Focusing on Korea Railroad Research Projects

  • Baek, Seunghee;Hwang, Sungup;Park, Young Il
    • Asian Journal of Innovation and Policy
    • /
    • 제7권3호
    • /
    • pp.438-456
    • /
    • 2018
  • This study aims to understand the importance of commercialization of research and development projects and examines key factors that allow successful technology transfer and commercialization. Given the characteristics of the railway research project, and assuming that R&D input factors would vary depending on the technology readiness level and the degree of research convergence, this study analyzes the moderating effect of each R&D input factor on technology transfer and commercialization to determine their eventual impact. Through this study, it was found that it was necessary to proceed to technology transfer and commercialization of the national research and development projects via strategic workforce composition and allocation of research funding given the subjects and development goals of R&D projects.

영광 및 울진 원전 주변 논 토양으로부터 벼로의 년차별 $^{90}Sr$ 전이 (Annual Transfer of $^{90}Sr$ to Rice from Paddy Soils Collected around Yonggwang and Ulchin Nuclear Power Plants)

  • 임광묵;최용호;박효국;강희석;최희주;이한수
    • Journal of Radiation Protection and Research
    • /
    • 제28권4호
    • /
    • pp.271-279
    • /
    • 2003
  • 영광 및 울진 원전 반경 5 km 내 12 곳의 논토양 블록을 재배상자에 채취하여 벼의 이식 전과 출수 시작 $1{\sim}2$ 일 전에 $^{90}Sr$을 담수의 표면에 처리하였다. 이식 전 처리에 있어서는 전이계수를 $2{\sim}4$ 년 간 조사하였다. 이식전 처리시 당년도 $^{90}Sr$의 전이계수$(m^2\;kg^{-1}-dry\;plant)$는 지역 간에 이렇다할 차이없이 토양에 따라 2 배 정도의 변이를 보였고 평균은 쌀알의 경우 $2.6{\times}10^{-4}$, 볏짚의 경우 $1.3{\times}10^{-2}$였다. 출수 전 처리시 전이계수는 이식전 처리에 비해 대체로 2 배정도 높았다. 토양의 pH와 치환성 Ca 함량이 높을수록 $^{90}Sr$ 전이계수가 감소하는 경향이었다. 우리나라 논에 대하여 침적 당년도 $^{90}Sr$ 전이계수의 대표치가 제안되었다. 처리 1차 년도에 대한 2차 년도 전이계수의 감소 정도는 대체로 모래함량이 높은 울진 토양에서 영광 토양보다 높았다. 영광 토양 전체로 볼 때 년차에 따른 전이계수의 감소는 반감기가 2.2년 정도의 지수함수로 묘사될 수 있었다.

공공연구기관의 기술이전 유형별 성공요인 사례연구 (A Qualitative Analysis on the Success Factors in Technology Transfer of Korean Government Sponsored Research Institutes)

  • 윤기동;김병근
    • 기술혁신학회지
    • /
    • 제21권2호
    • /
    • pp.491-521
    • /
    • 2018
  • 본 연구는 우리나라 공공연구기관의 기술이전 성공요인들을 분석한다. 기술이전과정의 특성을 반영하여 기술이전 유형을 공급주도형, 수요주도형, 상호작용형 등 3가지로 구분하여 분석한다. 기술이전 성공요인들을 분석하기 위해 기술이전 이해당사자(Subject), 기술(Object), 기술이전 과정(Process)을 중심으로 분석모형을 제시한다. 본 연구는 다중사례연구방법론을 사용하여 대표적인 정부출연 연구기관 3곳의 기술이전 유형별 성공사례를 각각 2건 선정하고, 심층인터뷰를 통하여 세 가지 기술이전 유형의 공통점과 차이점을 중심으로 기술이전 성공요인들을 분석하였다. 사례연구 결과 연구자의 역량과 경험, 기업의 의지와 역량, 기술의 특성, 기술이전과정상 주체 간 의사소통 등이 기술이전의 중요한 성공요인인 것으로 분석되었다. 특히 수요주도형에서는 기술이전이 TLO 주도로 진행된다는 사실을 확인할 수 있었다. 또한, 공급주도형에 비해 수요주도형과 상호작용형이 기업이 직접 기술개발 및 이전과정에 참여함에 따라 기업 수요 반영에 용이한 구조로 조사되었다. 즉, 기술 중심의 R&D가 아니라 시장 중심의 R&D의 필요성을 확인한 것이다. 아울러, 성공적 기술이전의 주요 요건중 하나는 TLO의 역량강화 및 역할, 인식에 있어서 개선임을 지적하였다.

Temperature and Electric Field Effect on Proton Transfer in Adenine-thymine

  • Zhang, Guiqing;Xie, Shijie
    • Bulletin of the Korean Chemical Society
    • /
    • 제35권12호
    • /
    • pp.3532-3534
    • /
    • 2014
  • In theoretical simulations of proton transfer in DNA, environmental factors nearly have not been considered. In our calculations, using QM/MM method on the basis of CP2K, proton transfer on adenine-thymine base pair is studied in water, at wide scope temperature, and under the external electric field. Our results indicate that the external electric field induces the proton transfer at room temperature, and its intensity and temperature have some effect on hole localization and proton transfer.

수도권 도시철도 환승율 및 실수송수요 분석 (Transfer Rate and Actual Ridership of Urban Railways in the Seoul Metropolitan Area)

  • 고준호;김경철
    • 한국철도학회:학술대회논문집
    • /
    • 한국철도학회 2001년도 춘계학술대회 논문집
    • /
    • pp.36-43
    • /
    • 2001
  • Although the transferring is one of the most important factors in urban railways, there is very little analytic research in the transfer-related field. This paper analyses the transfer rate of urban railways in the Seoul Metropolitan Area and the actual passenger boardings and alightings at transfer stations using the AFC(Automatic Fare Collector) O/D data collected doling Sep. 2000. According to the results of this study the transfer rate is 0.657, which is calculated from the transfer hoardings/initial boardings. And the actual ridership of Subway Line 2 and Line 5 are different from the data which was provided by the AFC.

  • PDF