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        검색결과 50

        1.
        2023.11 구독 인증기관·개인회원 무료
        In the case of nuclear projects, when developing a new reactor type, it is necessary to confirm the reactor type, secure the safety, and especially obtain the construction permit approval of the licensing authority for construction. Schedule management is necessary to carry out nuclear projects, and progress rate management of project progress management is largely composed of three elements: scope management, cost management, and resource management. However, in the case of the small modular reactor (SMR) project currently being carried out, it is difficult to calculate the progress rate including budget and resources due to the nature of the project. Therefore, in the SMR project, it took two years from the beginning to prepare the integrated project master schedule (IPMS) to prepare the draft, and then two revisions were made over a year and a half. In this SMR project, we will consider the entire construction period such as design, purchase and production, construction, commissioning, and operation in terms of scope management. The entire document list was created using the document review and approval sheet created at the beginning of the design. In the PMIS (Project Management Information System), the number of approved documents was calculated by comparing the list of engineering documents. In the purchase production part, the main core equipment such as the primary system nuclear steam supply system (NSSS), the secondary system turbine and condenser, and the man machine interface system (MMIS) are managed. Purchasing and manufacturing management shall be managed so that major equipment can be delivered in a timely manner in accordance with the schedule for delivery of equipment in the IPMS. In order to prevent delays in the start of production, it is necessary to minimize the waiting time for work through advance management tasks such as insurance of drawing, stocking of materials, availability of production facilities, etc. In this way, we decided to carry out the schedule management for the design, purchase and manufacturing part in the SMR project first, and the installation, construction and commissioning part will be prepared for the future schedule management.
        19.
        2018.10 구독 인증기관·개인회원 무료
        We investigated primary ecological characters, such as life cycle and morphology of the lawn cutworm, Spodoptera depravata (Lepidoptera: Noctuidae), which is one of the most economically damaging pests to grasses. For larval culture the turfgrass, Zoysia japonica, was provided as a feed source at 25℃ and 60±5% humidity. Development period of each stage was as follows: 4.11±0.19 days for eggs, 25.17±3.02 for larvae, 8.80±0.28 for pupae and 7.57±0.95 for adults. Larval stages continued to 7th instar and this result contrasts to pre-existing data, which indicate 6th instar in S. depravata. Developmental period of each instar of S. depravata ranged from the minimum of 2.1 days to the maximum of 4.81 days, with the 7th instar longest. Correlation analysis between body length and head capsule width of each instar showed a significant correlation between the two measures. Pupal colors were changed from the light brown and green right after pupation to dark brown as pupal cuticle hardens. Wing length of adults in both sexes was similar, but forewing of male had obvious outer line and eyespot with dark gray-brown background, whereas that of female had less obvious in these characters, with light gray-brown background. Pre-period of eggs deposition was 2 days, oviposition period was 4.6 days, average fecundity per female was about 419 eggs, and rate of hatching was about 83%.
        20.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mesenchymal stem cells (MSCs) have been considered an alternative source of neuronal lineage cells, which are difficult to isolate from brain and expand in vitro. Previous studies have reported that MSCs expressing Nestin (Nestin+ MSCs), a neuronal stem/progenitor cell marker, exhibit increased transcriptional levels of neural development-related genes, indicating that Nestin+ MSCs may exert potential with neurogenic differentiation. Accordingly, we investigated the effects of the presence of Nestin+ MSCs in bone-marrow-derived primary cells (BMPCs) on enhanced neurogenic differentiation of BMPCs by identifying the presence of Nestin+ MSCs in uncultured and cultured BMPCs. The percentage of Nestin+ MSCs in BMPCs was measured per passage by double staining with Nestin and CD90, an MSC marker. The efficiency of neurogenic differentiation was compared among passages, revealing the highest and lowest yields of Nestin+ MSCs. The presence of Nestin+ MSCs was identified in BMPCs before in vitro culture, and the highest and lowest percentages of Nestin+ MSCs in BMPCs was observed at the third (P3) and fifth passages (P5). Moreover, significantly the higher efficiency of differentiation into neurons, oligodendrocyte precursor cells and astrocytes was detected in BMPCs at P3, compared with P5. In conclusion, these results demonstrate that neurogenic differentiation can be enhanced by increasing the proportion of Nestin+ MSCs in cultured BMPCs.
        4,000원
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