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        검색결과 9

        1.
        2022.05 구독 인증기관·개인회원 무료
        The mechanical safety of the container designed according to the IP-2 type technology standard was analyzed for the temporary storage and transportation of Very-Low-Level-Waste (VLLW) for liquid occurring at the nuclear facilities decommissioning site. The container was designed and manufactured as a composite shielding container with the effect of storing and shielding liquid radioactive waste using High Density Polyethylene (HDPE) and eco-friendly shielding material (BaSO4) with corrosion and chemical resistance. The main material of the composite shielding container is HDPE and BaSO4, the material of the cover, cage and pallet is SUS304, and the angle guard is elastic rubber. The test and analysis requirements were analyzed for structural analysis of container drop and lamination test. As test requirements for IP-2 type transport containers should be verified by performing drop and lamination tests. There should be no loss or dispersion of contents through the 1.2 m high free-fall drop and lamination test for a load five times the amount of transported material. ABAQUS/Explicit, a commercial finite element analysis program, was used for structural analysis of the drop and lamination test of the transport and storage container. (Drop test) It was confirmed that the container was most affected when it falls from a 45-degree slope. Although plastic deformation was observed at the edge axis of the cover, it was evaluated that the range of plastic deformation was limited to the cover and cage, and stress within the elastic limit occurred in the inner container. In the analysis results for other falling direction conditions, it was evaluated that stress within the elastic limit was generated in the inner container except for minor plastic deformation. In the case of on-site simulation evaluation, deformation of the inner container and frame due to the drop impact occurred, but leakage and loss of contents, which are major evaluation indicators, did not occur. (Lamination test) The maximum stress was calculated to be 19.9 MPa under the lamination condition for a load 5 times the container weight, and the maximum stress point appeared at the corner axis of the pallet. The calculated value for the maximum stress is about 10%, assuming the conservative yield strength of SUS304 is 200 MPa. It was evaluated that stress within the limit occurred. In the case of on-site simulation evaluation, it was confirmed that there was no container deformation or loss of contents due to the load.
        5.
        2012.06 구독 인증기관·개인회원 무료
        There are diverse methods of cryopreservation of mammalian embryos with variable degrees of success. Although cryopreservation technique of mammalian embryos has been advanced, freezing stress affect to cellular event such as apoptosis and autophage in embryos. The objective of the study is to investigate the affection of to survival, development, live offspring, apoptosis and autophagy on embryo. Mouse embryos were vitrified and thawed using normal straw and modified cut standard straw (M-CSS), then in vitro cultured until blastocyst stage and transferred to recipient. Recovery rates (100 vs 99.2%), survival rates (99.2 vs 78.6%), developmental rates (18.4 vs 10.7%), total cell numbers (45 vs 37), preganacy rates (34.5 vs 25%) and offspring numbers (10.1 vs 4.9 %) of M-CSS group are significantly higher than those of normal straw vitrified group. Also, rate of apoptosis in blastocysts developed using M-CSS (1.9%) was significantly lower than using normal straw vitrification (2.7%). Apoptosis-related gene, caspase 3, was expressed at the highest level in blastocysts derived from normal straw group. However, no differences of autophagy related gene, Atg6 and expression of LC3 between normal straw and M-CSS groups were observed. In conclusion, the standard vitrification procedure induces mitochondrial apoptosis in zygotes in an autophagy-independent manner, whereas the novel M-CSS procedure may improve embryo vitrification.