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        검색결과 9

        1.
        2022.10 구독 인증기관·개인회원 무료
        The number of dismantled nuclear facilities is increasing globally. Dismantling of nuclear facilities generates large amount of waste such as concrete, soil, and metal. Concrete waste accounts for 70% of the total amount of waste. Since hundreds of thousansds of tons of concrete waste generated, securing technology of reduction and recycling of waste is emerging as a very important issue. The objective of this study is to synthesize geopolymer using inorganic materials from cement fine powder in concrete waste. Dismantled concrete waste contains a large amount of calcium silicate hydrate(C-S-H), Ca(OH)2, SiO2, etc., which is an inorganic material required for the synthesis of geopolymer. SiO2 affects the compressive strength of the geopolymer and Ca(OH)2 affects the curing rate. A high concentration of alkali solution is used as an alkali activator, and alkali activator is necessary for the polymerzation reaction of metakaolinite. The experiment consists of three steps. The first step is to react with concrete waste and hydrochloric acid to extract ions. In the solid after filtration, SiO2 and Al2O3 are composed of 84.10%. It can be used instead of commercial SiO2 required for the synthesis of geopolymer. The second step is to add NaOH up to pH 10, impurities can be removed to extract Ca(OH)2 with high purity. The final step is to add NaOH up to pH 13, and Ca(OH)2 extraction. The alkali solution generated after the last reaction can be recycled into an alkali activator during the synthesis of the geopolymer. If dismantled concrete waste is recycled during geopolymer synthesized, the volume reduction rate of dismantled concrete waste is more than 50%. If you put the radioactive waste in the recycled solidification materials synthesis from concrete waste by dismantling of nuclear facilities, it is possible to reduce the amount of waste generated and disposal costs.
        2.
        2022.10 구독 인증기관·개인회원 무료
        Kori-1, the nuclear power plants in South Korea, first started operation in April 1978 and was suspended permanently in 2017. The saturation rate time of spent nuclear fuel generated by major nuclear power plants operating in Korea are getting closer. If we fail to dispose spent nuclear fuel, which is equivalent to high-level radioactive waste, the nuclear power plants will have to be shutdown. High-level radioactive waste is permanently disposed through a deep geological disposal system because it contains long-term half-life nuclides and emits high energy. To select the deep geological disposal site and construct the disposal facilities, it is necessary to establish appropriate regulatory policies accordingly. The status of database construction in OECD-NEA, NRC, SITEX, and IAEA, which provides safety regulations for deep geological disposal system, stipulates each requirement for dismantling nuclear power plants. However, details such as specific figures are not specified, and guidelines for the disposal of high-level radioactive wastes are not clearly distinguished. In Korea, the CYPRUS program, an integrated database system, has been developed to support comprehensive performance evaluation for high-level waste disposal. However, due to several difficult situations, maintenance and upgrades have not been performed, so the research results exist only in the form of raw data and the new research results have not been reflected. Other than that, there is no preemptive basis for regulating the deep geological disposal system. With real-time database, we can develop a regulatory system for the domestic deep disposal system by systematically analyzing the regulatory condition and regulatory case data of international organizations and foreign leading countries. The database system processed and stored primary data collected from nuclear safety reports and other related data. In addition, we used relational database and designed table to maximize time and space efficiency. It is provided in the form of a web service so that multiple users can easily find the data they want at the same time. Based on these technologies, this study established a database system by analyzing the legal systems, regulatory standards, and cases of major foreign leading countries such as Sweden, Finland, the United States, and Japan. This database aims to organize data for each safety case component and further prepare a safety regulatory framework for each stage of development of disposal facilities suitable for the domestic environment.
        3.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to evaluate the effect of the exercise on elderly balance ability by using hippotherapy and therapeutic ball exercise. 10 patients were assigned to the hippotherapy group and they got with 30 minutes of hippotherapy. Another 10 elderly were assigned to the therapeutic ball group and they got with 30 minutes of therapeutic ball exercise. All procedures were repeated 5 times a week for the total of four weeks. To investigate the participants balancing abilities, the Time“ Up & Go”(TUG) and One Leg Stand Test(OLST) were evaluated. The results of study were significant differences between pre-test and post-test of TUG and OLST(p<.05), and there were no significant differences between hippotherapy and therapeutic ball exercise(p>.05). The conclusion showed that both the hippotherapy and the therapeutic ball exercises were effective on elderly balancing ability. Consequently, it would be better to practice therapeutic ball than hippotherapy for elderly exercise because the more economical and there is less restriction of space than the hippotherapy.
        4,000원
        4.
        2008.09 구독 인증기관 무료, 개인회원 유료
        Innate immune response is initiated by the recognition of unique microbial molecular patterns through pattern recognition receptors (PRRs). The purpose of this study is to dissect the expression of various PRRs in gingival epithelial cells of differentiated versus undifferentiated states. Differentiation of immortalized human gingival epithelial HOK-16B cells was induced by culture in the presence of high Cα²+ at increased cell density. The expression levels of various PRRs in HOK-16B cells were examined by realtime reverse transcription polymerase chain reaction (RTPCR) and flow cytometry. In addition, the expression of human beta defensins (HBDs) was examined by real time RT-PCR and the amounts of secreted cytokines were measured by enzyme linked immunosorbent assay. In undifferentiated HOK-16B cells, NACHT-LRR-PYDcontaining protein (NALP) 2 was expressed most abundantly, and toll like receptor (TLR) 2, TLR4, nucleotide-binding oligomerization domain (NOD) 1, and NOD2 were expressed in substantial levels. However, TLR3, TLR7, TLR8, TLR9, ICE protease-activating factor (IPAF), and NALP6 were hardly expressed. In differentiated cells, the levels of NOD2, NALP2, and TLR4 were different from those in undifferentiated cells at RNA but not at protein levels. Interestingly, differentiated cells expressed the increased levels of HBD-1 and -3 but secreted reduced amount of IL-8. In conclusion, the repertoire of PRRs expressed by gingival epithelial cells is limited, and undifferentiated and differentiated cells express similar levels of PRRs.
        4,000원
        5.
        2018.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The present study was carried out to investigate the physicochemical properties of hot water extracts of red ginseng powder prepared by two-stage hot air drying method using steamed ginseng and steaming liquid for 2.5 h under high-temperature and high-pressure autoclave condition. The total polyphenols, total flavonoids, total sugar, acid polysaccharides and crude saponin in hot water extracts from red ginseng powder were analyzed and determined, and the flavor components of ginseng were measured using color difference meter and an electronic tongue. The total polyphenol, total flavonoid, total polysaccharide, and acid polysaccharide of the red ginseng hot water extract obtained by autoclaving (ARG) were 9.06 mg GAE/g, 3.38 mg NE/g, 35.22 g/100 g, and 10.90 g/100 g, respectively. The final contents of the total polyphenols, total flavonoids, crude saponin were higher than those determined using other red ginseng methods; the time required for steamed red ginseng production reduced. The total ginsenoside content of ginseng including Rb1 was 10.69 mg/g, which is the lowest ARG. The processing conditions affected the conversion to ginsenosides unique to red ginseng. Red ginseng and steaming liquid obtained from the autoclave are expected to be in need for non-food materials and products as well as foods by improving the flavor components through conversion of red ginseng components into low molecular weight.
        6.
        2017.05 서비스 종료(열람 제한)
        Background : Arctii Radix (the dried roots of Arctium lappa L., AR) is used in traditional medicine to treat oxidative stress related diseases including cancer. Therefore, this study focuses on the antioxidant potential of AR as extraction solvents. Methods and Results : To increase the extraction amount of active ingredient, the AR were extracted by ethanol (ARE) and water (ARW). In order to determine active ingredient content of AR, we were carried out total polyphenolic (TPC) and flavonoid content (TFC) analyses. As a result, TPC (47.74 ± 1.02 g․GAE/㎏ extract) and TFC (19.34 ± 0.30 g․CTE/㎏ extract) of ARE were found significantly higer as compared to ARW. The IC50 values based on the DPPH (59.00 ± 3.25 ㎍/㎖), ABTS (93.20 ± 1.30 ㎍/㎖), ROS (57.78 ± 3.44 ㎍/㎖) and ONOO- (14.56 ± 1.24 ㎍/㎖) for ARE were generally stronger showing potential antioxidant properties compared to ARW. Conclusion : Data from results revealed Arctii Radix ethanol extracts act as an antioxidant agent due to its free radical scavenging activity.
        7.
        2015.09 KCI 등재 서비스 종료(열람 제한)
        The seasonal variation of phytoplankton communities and its standing crops in accordance with environmental factors were investigated at Yeongrang-ho, Cheongcho-ho, Mae-ho and Hyang-ho which are located in the East coast of Korea during April to October 2011. High concentrations of T-N and T-P were observed in four lagoons due to the inflowing nutrients from farmlands and residential areas near lagoons. Nutrient salts mainly composed of nitrogen and phosphate caused the eutrophication of the lakes, leading to the robust growth of phytoplankton. During the period of investigation, 64 to 107 taxa of phytoplankton were observed in four lagoons. Diatoms were the most dominant species with high density. Non-point pollution source was estimated as the main cause of water pollution of lagoons. Trophic states of lagoons evaluated using the value of TSI and TSIKO indicated that all the investigated lagoons were in the eutrophication state.
        8.
        2013.03 서비스 종료(열람 제한)
        Spontaneous perirenal hematoma is an unusual but serious complication of tumors, vascular disease, ruptured cyst, or infection. The authors report the case of a diabetic patient who presented with spontaneous perirenal hematoma and who was subsequently diagnosed to have emphysematous pyelonephritis.