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        검색결과 111

        52.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ni-W(1-5 at.%) alloy rods were made by powder metallurgy process including powder mixing, compacting and subsequent sintering. Ni and W powder of appropriate compositions were mixed by a ball milling and isostatically pressed in a rubber mold into a rod. The compacted rods were sintered at at a reduced atmosphere for densification. The lattice parameters of Ni-W alloys were estimated by a high resolution neutron powder diffractometer. All sintered rods were found to have a face centered cubic structure without any impurity phase, but the diffraction peak locations were linearly shifted with increasing W content. The lattice parameter of a pure Ni rod was which is consistent with the value reported in JCPDS data. The lattice parameter of N-W alloy rods increased by for 1 atomic % of W, which indicates the formation of a Ni-W solid solution due to the substitution of nickel atoms by tungsten atoms of larger size.
        4,000원
        57.
        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
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