• 제목/요약/키워드: College transfer

검색결과 2,854건 처리시간 0.036초

Study on Embryo Transfer System for Production of Transgenic Pigs

  • Na, Seungwon;Lee, Euncheol;Kim, Ghangyong;Min, Kyuhong;Yu, Youngkwang;Roy, Pantu Kumar;Fang, Xun;Hassan, Bahia Mohamed Salih;Yoon, Kiyoung;Shin, Sangtae;Cho, Jongki
    • 한국수정란이식학회지
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    • 제30권4호
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    • pp.345-350
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    • 2015
  • In the last 10 years, porcine somatic cell nuclear transfer to generate transgenic pig has been performed tremendous development with introduction and knockout of many genes. However, efficiency of porcine somatic cell nuclear transfer is still low and embryo transfer (ET) is one of important step for production efficiency. In porcine ET for production of transgenic cloned pig, we can consider many of points to increase production rates. In respect of seasonality and weather, porcine ET usually is not performed in summer and winter. Cloned transgenic embryos must be transferred into reproductive tracts of recipients where embryos are located after natural fertilization with similar estrous cycle. If cloned embryos with 2~4 cell stage are transferred, they must be transferred into oviducts in periovulatory stage. Number and deposition sites of transferred cloned embryos are important. And we must compare the methods of ET between surgical and non-surgical ones in respect of production efficiency. Sow recipients after natural estrus is most preferred recipients however its cost is must be considered. Here we will review many of current studies about porcine embryo transfer to increase production efficiency of transgenic pigs and strategies for further studies.

경영이양활성화를 위한 농업경영이양의 제도적 고찰 (An Institutional Review of Farming Transfer to Revitalize Management Transfer)

  • 이소영;김진진
    • 현장농수산연구지
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    • 제22권2호
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    • pp.23-36
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    • 2020
  • The purpose of this study is to understand the phenomenon of agricultural management transfer and to present a plan to activate Korean management transfer through institutional consideration. To this end, the domestic and overseas agricultural management transfer system was identified, and an appropriate institutional plan for the country was sought. There are six ways to activate the management transfer system proposed in this study. First, establishment of an agricultural management transfer agency, second, training and utilization of management transfer experts, third, establishment of an agricultural succession certification support institution, fourth, operation of specialized training courses for management transfer, fifth, (local government) linked operation of a farming support center, sixth, agricultural management transfer legislation and securing of budgets. The above agricultural management transfer system is expected to contribute to the advancement of management transfer activation.

Heat Transfer Characteristics of Liquid-Solid Suspension Flow in a Horizontal Pipe

  • Ku, Jae-Hyun;Cho, Hyun-Ho;Koo, Jeong-Hwan;Yoon, Suk-Goo;Lee, Jae-Keun
    • Journal of Mechanical Science and Technology
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    • 제14권10호
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    • pp.1159-1167
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    • 2000
  • Particles in liquid-solid suspension flow might enhance or suppress the rate of heat transfer and turbulence depending on their size and concentration. The heat transfer characteristics of liquid-solid suspension in turbulent flow are not well understood due to the complexibility of interaction between solid particles and turbulence of the carrier fluid. In this study, the heat transfer coefficients of liquid-solid mixtures are investigated using a double pipe heat exchanger with suspension flows in the inner pipe. Experiments are carried out using spherical fly ash particles with mass median diameter ranging from 4 to $78{\mu}m$. The volume concentration of solids in the slurry ranged from 0 to 50% and Reynolds number ranged from 4,000 to 11,000. The heat transfer coefficient of liquid-solid suspension to water flow is found to increase with decreasing particle diameter. The heat transfer coefficient increases with particle volume concentration exhibiting the highest heat transfer enhancement at the 3% solid volume concentration and then gradually decreases. A correlation for heat transfer to liquid-solid flows in a horizontal pipe is presented.

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An Electric-Field Coupled Power Transfer System with a Double-sided LC Network

  • Xie, Shi-Yun;Su, Yu-Gang;Zhou, Wei;Zhao, Yu-Ming;Dai, Xin
    • Journal of Power Electronics
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    • 제18권1호
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    • pp.289-299
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    • 2018
  • Electric-field coupled power transfer (ECPT) systems employ a high frequency electric field as an energy medium to transfer power wirelessly. Existing ECPT systems have made great progress in terms of increasing the transfer distance. However, the topologies of these systems are complex, and the transfer characteristics are very sensitive to variations in the circuit parameters. This paper proposes an ECPT system with a double-sided LC network, which employs a parallel LC network on the primary side and a series LC network on the secondary side. With the same transfer distance and output power, the proposed system is simpler and less sensitive than existing systems. The expression of the optimal driving voltage for the coupling structure and the characteristics of the LC networks are also analyzed, including the transfer efficiency, parameter sensitivity and total harmonic distortion. Then, a design method for the system parameters is provided according to these characteristics. Simulations and experiments have been carried out to verify the system properties and the design method.

한우 체외수정란이 이식된 수란우의 임신과 유산에 영향을 미치는 시술자 측 요인들 (Effect of Technical Aspect in Practitioner on the Pregnancy and Abortion after Transfer of In Vitro Produced Korean Native Cow Embryos)

  • 김소섭;박용수;박윤미;박흠대;심호섭;김남형
    • 한국수정란이식학회지
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    • 제20권1호
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    • pp.9-15
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    • 2005
  • 본 연구는 임상 조건하에서 수정란이식의 효율성 증대를 위하여 이식 시술자 측면의 숙련도, 난이도, 소요시간, 주입 위치, 자궁의 출혈 및 위치 조절이 체외수정란이 이식된 수란우의 임신과 유산에 미치는 효과를 검토하였다. 임신율은 숙련된 시술자$(54.2\%)$, 자궁각 2/3 지점에 이식$(46.9\%)$ 및 위치 조절군$(52.9\%)$이 유의하게 높은 경향이었으나, 이식 난이도, 소요시간 및 출혈에 따른 차이는 인정되지 않았다. 한편 시술자 측의 요인에 따른 유산율은 유사한 경향이었다.