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        검색결과 67

        23.
        2006.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is essential to develop the shield for the extraction of high quality neutron beam and safe work at the sample position. The aim of this study is design, fabrication and filling of the shield in domestic. In consideration of ST-3 beam port of HANARO, we designed the reflectometer shield composed of 14 blocks and fabricated it shield casemate. Through the assembly and quality test of the shield casemate, we established the method of fabrication for neutron beam path and channel. In order to increase shield capacity, we filled shield casemate with heavy concrete, lead ingot and polyethylene that mixed B4C powder and epoxy. The average density of the filled heavy concrete was 4.7g/cm3, which can protect neutron and gamma ray effectively. Also, we developed ancillary equipment such as beam gate unit(BGU, vertical type) for the effective opening and closing of neutron beam. Shielding block was proved by suitable thickness as result that measure surface dosage using of detector and TLD. The acquired technique of design, fabrication and filling of ancillary equipment development can be applicable to the development of shield for the other neutron spectrometer in future.
        4,000원
        24.
        2006.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Conventional product development process employs a design-build break philosophy which is sequentially executed product development process. It often results in a prolonged lead-time and a high product cost. This paper proposes the concurrent engineering design approach integrating design process to solve the above problems. The proposed approach in this paper holds potential for shortening the overall product development cycle, improving product quality, and reducing product cost. This paper presents three concepts and methods for product development : (1) considering product performance, quality and cost together in early design stage, (2) supporting design decision-making through a quantitative approach, and (3) incorporating rapid prototyping and virtual prototyping for design verification.
        4,000원
        37.
        2004.12 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to assess sperm characteristics in miniature-pig. The semen samples were transported to the laboratory at 17℃ within 3 hours after collection. The extended semen was stored at 17℃, and sperm quality was evaluated at 0, 1, 3, 5 and 7 days after storage. The semen volume of miniature-pig (62±22㎖) was significantly (p<0.05) lower than that of Duroc (155±25㎖) and Yorkshire (154±23㎖). Significant differences were also observed in sperm concentrations. During 3 days of storage, sperm viability did not differ among miniature-pig, Duroc and Yorkshire. However, the viability was significantly (p<0.05) lower in miniature-pig than in Duroc and Yorkshire semen after Day 3 of storage. In abnormality, acrosome intactness and intensity, there were no differences among miniature-pig, Duroc and Yorkshire semen. On the other hand, the viability of frozen-thawed sperm in miniature-pig was significantly (p<0.05) lower than in that of Duroc and Yorkshire. This study also examined CTC patterns in frozen-thawed spermatozoa. The rates of AR pattern were higher in miniature-pig than in Duroc and Yorkshire. However, no difference was found in F, B and AR patterns. The results of present study suggest that further research is necessary to develop of semen extender and freezing methods to improve sperm quality in miniature-pig.
        4,000원
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