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        검색결과 60

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 정원에 대한 관심이 증가함에 따라 자생 식물을 활용 하기 위한 연구가 진행되고 있다. 참식나무(Neolitsea sericea (Blume) Koidz).는 관상용뿐만 아니라 목재로도 이용할 수 있 다. 따라서 이 연구는 참식나무를 정원 식물 소재로 활용하기 위한 대량 증식 기술 개발을 위하여 종자의 발아 특성과 저장 특성에 대해 알아보고자 진행하였다. 2022년 11월 2일 제주 지역에서 채집한 종자를 실험에 사용하였다. 종자의 내·외부 형태 관찰을 한 결과, 종자가 탈리되는 시점에 배가 완전히 발 달한 형태를 가지고 있기 때문에 형태적휴면(morphological dormancy, MD)이 없음을 확인할 수 있었다. 수분흡수 실험 을 통하여 참식나무 종자는 72시간 이후 40% 정도의 수분흡수 율을 보여 내과피의 불투성에 의한 물리적휴면(PY, physical dormancy)이 없는 것으로 판단하였다. 채종 후 곧바로 무가 온 온실에 파종하면 이듬해 5월에 약 60%가 발아하였다. 저 온습윤처리 0, 2, 4, 8, 12주 후 25/15°C에 배양한 결과 최 종 발아율은 각각 0%, 0%, 21.1%, 32.6%, 34.7%였다. GA3 를 0, 10, 100, 1000mg·L-1 농도로 처리한 후 25/15°C에서 배양한 결과, 최종 발아율은 각각 0, 14.5, 22.7, 42.2%였다. 따라서 본 실험의 결과 8주 이상의 저온 처리 또는 GA3 처리 를 통하여 어느 정도 휴면을 타파시킬 수 있었다. 이러한 결과 를 통하여 종자는 intermediate PD를 가지는 것으로 판단 된다. 일부 발아하지 않은 종자는 deep PD를 가지고 있는 것 으로 판단하였다. 후숙 처리 실험의 결과 4주 만에 수분 함량 이 2% 이하로 감소하였고 종자는 전혀 발아하지 않았다. 따라 서 종자의 저장 특성 중 recalcittrant 특성을 지닌 난저장성 종자로 보인다.
        4,000원
        2.
        2023.11 구독 인증기관·개인회원 무료
        Molten Salt Reactor, which employs molten salt mixture as fuel, has many advantages in reactor size and operation compared to conventional nuclear reactor. In developing Molten Salt Reactor, the behavior of fission product in operation should be preliminary evaluated for the correct design of reactor and its associated system including off-gas treatment. In this study, for 100 Mw 46 KCl- 54 UCl3 based Molten Salt Reactor with operating life time of 20 year, the fission product behavior was estimated by thermodynamic modeling employing FactSage 8.2. Total inventory of all fission product were firstly calculated using OpenMC code allowing depletion during neutronic calculation. Then, among all inventory, 46 element species from Uranium to Holmium were chosen and given to the input for equilibrium module of Factsage with its mass. In phase equilibrium calculation, for the correct description of solution phase, KCl-UCl3 solution database based on modified quasichemical model in the quadruplet approximation (ANL/CFCT-21/04) was employed and the coexisting solid phase was assumed to pure state. With the assumption of no oxygen and moisture ingress into reactor system, equilibrium calculation showed that 1% of solid phase and of gas phase were newly formed and, in gas phase, major species were identified : ZrCl4 (47%), Xe (33%), UCl4 (14%), Kr (5%), Ar (1%) and others. This result reveals that off-gas treatment of system should account for the appropriate treatment of ZrCl4 and UCl4 besides treatment of noble gas such as Xe and Kr.
        7.
        2022.10 구독 인증기관·개인회원 무료
        According to the Nuclear Safety and Security Commission (NSSC) Notice No. 2021-26 “Delivery Regulations for the Low- and Intermediate Level Radioactive Waste (LILW)”, the activity of 3H, 14C, 55Fe, 58Co, 60Co, 59Ni, 63Ni, 90Sr, 94Nb, 99Tc, 129I, 137Cs, 144Ce, and gross alpha must be identified. Currently, the scaling factor of the dry active waste (DAW) for LILW is applied as an indirect evaluation method in Korea. The analyses are used the destructive methods and 55Fe, 60Co, 59Ni, 63Ni, 90Sr, 94Nb, 99Tc, and 137Cs, which are classified as nonvolatile nuclides, are separated through sequential separation and then measured by gamma detector, liquid scintillation counter (LSC), alpha/beta total counter (Gas Proportional Counter, GPC), and ICP-MS. We will introduce how to apply the existing nuclide separation method and improve the measurement method to supplement it.
        12.
        2020.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Globally, colon cancer is increased gradually and known as one of the major causes of cancer death. Stevia, a substitute of sugar, is known to have many components including alpha-tocopherol and anthocyanin etc, as antioxidants. This study's purpose is to investigate whether stevia plant extract can have a protective effect against colon carcinogenesis induced by azoxymethane (AOM) and dextran sodium sulfate (DSS) in mice. Total 30 male ICR mice were divided into 2 groups; AOM/DSS treatment (control group), AOM/DSS + stevia extract (0.5%, in drinking water). After acclimation for 1 week, five weeks old mice received three intraperitoneal AOM (10 mg/kg b.w.) injections weekly for 3 weeks (0–2nd weeks of the experiment) and 2% DSS as drinking water for the next one week. AIN-76A purified rodent diet and 0.5% stevia extract water were supplied to the animals for 6 weeks. The colons of mice were collected and the number of aberrant crypt foci (ACF) and aberrant crypts (ACs) in colonic mucosa were counted after staining with methylene blue. Malondialdehyde (MDA) concentration in feces were determined. The numbers of ACF and ACs were significantly (p<0.01) decreased in stevia-treated group compared with the control group. The MDA concentration in feces was also significantly (p<0.01) decreased in stevia-treated group compared with the control group. In histopathology of colonic epithelium, hyperplasia of colonic epithelium was less observed in steviatreated group. These results indicate that stevia has a protective effect against colon carcinogenesis induced by AOM/DSS in mice and further study needs to illustrate the protective mechanisms.
        4,000원
        15.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To enhance the thermal properties of epoxy composites, expanded graphite (EG) was oxyfluorinated and embedded into epoxy resin as a reinforcement. The maximum thermal conductivity was obtained for epoxy composites with oxyfluorinated EG, representing a 62% increase compared to that of neat epoxy. Additionally, the glass transition temperature (Tg) and integral procedural decomposition temperature of epoxy composites with oxyfluorinated EG show the increase of 6% (4.4 °C) and 106% (264 °C), respectively, which indicated the improvement in thermal stability. These results can be attributed to the interfacial interaction between epoxy and oxyfluorinated EG, which formed strong interfacial interactions between the epoxy resin and EG due to the presence of oxygen- and fluorine-containing functional groups in oxyfluorinated EG.
        4,000원
        18.
        2019.04 구독 인증기관·개인회원 무료
        The Nitidulidae includes 10 subfamilies and over 350 genera and 4500 species and is the largest family in Cucujoidea. We place the enigmatic subfamily Calonecrinae into the internal relationship of Nitidulidae, a comprehensive molecular phylogenetic analysis was performed using five gene regions (COI, 28s, CAD, H3, Wingless) for 80 taxa. We included 73 ingroup taxa representing nine of the ten currently recognized subfamilies of Nitidulidae and 7 outgroups. The phylogenetic results are consistent with prior molecular studies, that include a polyphyletic Nitidulinae with the inclusion of Meligethinae and Cillaeinae and that the Calonecrinae is sister taxon to Epuraeinae. Ancestral state reconstruction of feeding behavior indicates that stem group nitiduilds were most probably sap-feeding with transitions to other feeding types independently derived multiple times.
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