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        검색결과 22

        2.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerous studies have addressed the commercial viability of lithium–air batteries (LABs). However, the high reactivity of Li with air moisture and CO2 has hindered the broad applicability of LABs. In this study, lithium-protective hybrid lithium–air batteries (HLABs) were fabricated with Super P (SP) and composites of fluorinated carbon ( CFx), MoS2, and WS2 as the cathodes. Subsequently, their potential use as a power source for the next generation of defense technologies was investigated. It was observed that a single cell HLAB with the SP-CFx composite cathode exhibited a specific capacity of 893 mAhg− 1 cathode. In comparison, a Tomcell with the SP cathode demonstrated a specific capacity of 465 mAhg− 1 cathode when discharged. The cells with SP-MoS2 and SP-WS2 cathode yielded specific capacities of 357 and 386 mAhg− 1 cathode, respectively. The improved performance of the SP-CFx cell can be attributed to synergistic effects of lithium–air cell and lithium battery reactions between CFx and SP. To assess all functionalities of the SP-CFx HLAB, lithium-protective HLABs were fabricated and discharged in air. To operate the lithium–air battery in air, pure lithium metal was sealed with solid electrodes (lithium-ion conducting glass–ceramics (LICGC)) and a buffer electrolyte (1 M LiFTSI in TEGDME) was applied. The SP-CFx cell was discharged for 25 days in air, greatly exceeding the 72 h requirement for the next-generation soldier power systems. These results demonstrate significant potential for HLABs to be used as a pioneering power source in nextgeneration energy-independent tactical defense units.
        4,000원
        4.
        2021.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study evaluates the radioactivity of concrete waste that occurs due to large amounts of decommissioned nuclear wastes and then determines the surface dose rate when the waste is packaged in a disposal container. The radiation assessment was conducted under the presumption that impurities included in the bio-shielded concrete contain the highest amount of radioactivity among all the concrete wastes. Neutron flux was applied using the simplified model approach in a sample containing the most Co and Eu impurities, and a maximum of 9.8×104 Bq·g−1 60Co and 2.63×105 Bq·g−1 152Eu was determined. Subsequently, the surface dose rate of the container was measured assuming that the bio-shield concrete waste would be packaged in a newly developed disposal container. Results showed that most of the concrete wastes with a depth of 20 cm or higher from the concrete surface was found to have less than 1.8 mSv·hr−1 in the surface dose of the new-type disposal container. Hence, when bio-shielded concrete wastes, having the highest radioactivity, is disposed in the new disposal container, it satisfies the limit of the surface dose rate (i.e., 2 mSv·hr−1) as per global standards.
        4,000원
        5.
        2020.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Currently, radioactive waste for disposal has been restricted to low and intermediate level radioactive waste generated during operation of nuclear power plants, and these radioactive wastes were managed and disposed of the 200 L and 320 L of steel drums. However, it is expected that it will be difficult to manage a large amount of decommissioning waste of the Kori unit 1 with the existing drums and transportation containers. Accordingly, the KORAD is currently developing various and largesized containers for packaging, transportation, and disposal of decommissioning waste. In this study, the radiation exposure doses of workers and the public were evaluated using RADTRAN computational analysis code in case of the domestic onroad transportation of new package and transportation containers under development. The results were compared with the domestic annual dose limit. In addition, the sensitivity of the expected exposure dose according to the change in the leakage rate of radionuclides in the waste packaging was evaluated. As a result of the evaluation, it was confirmed that the exposure dose under normal and accident condition was less than the domestic annual exposure dose limit. However, in the case of a number of loading and unloading operations, working systems should be prepared to reduce the exposure of workers.
        4,300원
        8.
        2020.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        한국원자력환경공단은 처분시설 내 1단계 인수·저장구역의 인수검사 공간 및 드럼 취급 공간 부족에 대한 문제를 해결하기 위하여 방폐물검사건물을 건설하여 저장·처리능력을 확충할 예정이다. 본 연구에서는 MCNP 코드를 이용하여 방폐물검사 건물 내 저장구역에서 취급하는 해체 방사성폐기물 대상 신형처분용기를 대상으로 작업종사자의 피폭선량을 평가하였다. 평가결과, 시설 내 저장 가능한 최대 용기 개수(304개)와 방사선작업에 대한 연간 예상 작업시간(약 306시간)에 대하여 연간 집단선량은 총 84.8 man-mSv로 계산되었다. 시설 내 총 304개의 신형처분용기(소형/중형 타입)가 저장 완료된 시점에서 인수검사, 처분검사를 위한 작업종사자의 투입인력은 총 25명, 작업종사자 당 예상피폭선량은 연평균 3.39 mSv로 산출 되었다. 소형용기 취급 시 작업종사자의 고방사선량 작업에 따른 작업효율과 방사선적 안전성 확보를 위해서는 콘크리트 라이너의 두께를 증가시키는 추가적인 차폐가 필요할 것으로 평가되었다. 향후 본 연구를 바탕으로 실측기반의 해체폐기 물의 선원항과 특성을 활용하여 방사선작업 당 작업시간 및 투입인력을 산출함으로써 작업종사자의 최적의 방사선작업조건을 도출할 수 있을 것으로 사료된다.
        4,000원
        13.
        2014.06 구독 인증기관·개인회원 무료
        We have used bulked segregant analysis to screen the strain-specific DNA marker associated thermophilic strain of Pleurotus eryngii. Bulked genomic DNAs of Pleurotus eryngii were amplified by randomly amplified polymorphic DNA (RAPD) using OP-A, OP-B, OP-L, OP-P, OP-R and OP-S primers to screen the strain-specific DNA marker. A unique DNA fragment of 550 bp was amplified with OP-S07 primer from the thermophilic strain and sequenced. A sequence characterized amplified region (SCAR) marker was designed on the basis of the determined sequence and named as OP-S07-1. The PCR analysis with the OP-S07-1 primer showed that this SCAR marker clearly distinguish the thermophilic strains from the control strains.
        14.
        2014.04 구독 인증기관·개인회원 무료
        A full-length lysozyme cDNA from Gryllotalpa orientalis was cloned and sequenced. The deduced amino acid sequence of the lysozyme protein was 143 amino acids in length, with a calculated molecular mass of 15.84 kDa and an isoelectric point of 4.74. Sequence motifs, together with alignment and phylogenetic results, confirmed that G. orientalis lysozyme belongs to the C (chicken)-type lysozyme family of proteins. The protein sequence of lysozyme from G. orientalis showed high identity to that of Drosophila melanogaster (51.7%); however, in contrast to D. melanogaster lysozyme, G. orientalis lysozyme was immune inducible and expressed in a wide range of tissues. Expression of G. orientalis lysozyme mRNA was highest at 8 h post-infection and subsequently decreased with time after bacterial infection. We also expressed G. orientalis lysozyme protein in vitro using the pET expression system. Compared with the negative control, over-expressed G. orientalis lysozyme showed antimicrobial activity against Gram-negative bacteria Escherichia coli and Gram-positive bacteria Bacillus subtilis by radial diffusion assay, with MIC values of 30.3 μM and 7.55 μM respectively. These results indicate that G. orientalis lysozyme may have stronger antimicrobial activity than other lysozymes against a broad range of microorganisms.
        15.
        2014.04 구독 인증기관·개인회원 무료
        Hemocytes are key players in the immune response against pathogens in insects. However, the hemocyte types and their functions in the white-spotted flower chafers, Protaetia brevitarsis seulensis (Kolbe), are not known. In this study, we used various microscopes, molecular probes, and flow cytometric analyses to characterize the hemocytes in Protaetia brevitarsis seulensis. we identified the professional phagocytes, granulocytes (GRs), which mediate encapsulation and phagocytosis of pathogens. The GRs were immunologically or morphologically activated and phagocytosed potentially hazardous substances in vivo.
        17.
        2019.05 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study analyzes the effect of the capital structure of Korean manufacturing firms on default risk based on Moody’s KMV option pricing model where the probability of default is obtained by measuring the distance to default as a covariant in logit model developed by Merton (1974). Based on the panel data of manufacturing firms, this study achieves its primary objective, using a fixed effect regression model and examines the effect of a firm’s capital structure on default risk amongst publicly listed firms on Korea exchange during 2005-2016. Empirical results obtained suggest that the rise in short-term debt to assets leads to increase the risk of default whereas the increase in long-term debt to assets leads to decrease the default risk. The benefits of short-term debt financing over a short-term period fade out in the presence of information asymmetry. However, long-term debt financing overcomes the information asymmetry and enjoys the paybacks of tax advantage associated with long-term debt. Additionally, size, tangibility and interest coverage ratio are also the important determinants of default risk. Findings support the trade-off theory of capital structure and recommend the optimal use of long-term debt in a firm’s capital structure.
        18.
        2016.10 서비스 종료(열람 제한)
        Background : This study was conducted to serve as a basis for the production of high quality organic cultivation Platycodin grandiflorum Ridix roots by analyzing the content of saponins according to organic fertilizer for organic farming. Methods and Results : Platycodin grandiflorum Ridix was treated by with biodegradable film, rice husks, and sawdust, non-mulching (hand weeding). A root of Platycodon grandiflorum were analyzed saponins using HPLC harvested on October. Content of Plantycodin D3 was an average of 68.5 ㎎/100g, which appeared as 111.2 ㎎/100g highest content in the sawdust treated. Deapioplatycodin D showed the highest 48.1 ㎎/100g in the sawdust treated. The content of Platycodin D was shown to 246.2∼373.8 ㎎/100g, the highest values were observed in non-mulching, it showed the lowest value in the rice husks treated. The content of Polygalacin D showed up to 156.0 ㎎/100g in the non-mulching as the biggest difference, the lowest value were 30.1 and 32.2 ㎎/100g in sawdust and rice husks treated. Large differences between fertilizers was not showed, but the overall saponin content of Platycodin grandiflorum Ridix were low in value compared to the control than organic fertilizers. Conclusion : Large differences between mulching materials was showed, thus the overall saponin content of Platycodin grandiflorum Ridix was highest in value compared to non-mulching than sawdust treatment. Mulching Platycodin grandiflorum Ridix with sawdust was an effective method for improving saponin contents.
        19.
        2016.05 서비스 종료(열람 제한)
        Background : The root of Platycodin grandiflorum has been widely used as a crude drug or a dependent on the cultivation area and cultivation method. Therefore, this study was conducted to know the effect of organic fertilizer on the changes of antioxidents and antioxidant activity of Platycodin grandiflorum Ridix. Methods and Results : As basal fertilizer were treated before transplanting Platycodin grandiflorum Ridix with chemical fertilizer(Super21, 21-17-17, Namhae Chemical), mixed organic fertilizer, bacterial culture, fermented oil cake and manure in each trial of nitrogen based on 3㎏/10a criteria. The total polyphenol content was highest values were 15.5mg/g appear in the mixed organic fertilizers, the lowest were 9.1mg/g appeared in the manure and control. Flavonoid content showed the highest 15.3 mg/g in the mixed organic fertilizer, and investigated at the lowest 5.0 mg/g in the fermented oil cake. ABTS radical scavenging activity was the highest in was 65.7 mgTE/g in the chemical fertilizer, showed the lowest value in the control to 13.0 mgTE/g. Therefore, both flavonoid and polyphenol content showed a high value on organic fertilizers. Conclusion : Therefore, both flavonoid and polyphenol content showed a high value on organic fertilizers. It is determined that to have researches for a variety of antioxidants by the organic fertilizers made in the future.
        20.
        2014.12 KCI 등재 서비스 종료(열람 제한)
        Hyphessobrycon eques is a famous fish for ornamental fish market and aquarium. They are inhabit in regions of Amazon and Paraguay River basin. Serpae fishs were investigated 2–3 males are chased to female, and then males attempted to simulate the females abdomen. After fertilization, eggs were kept in incubators at 28oC. The fertilized eggs had adhesive and demesal characteristics and had a mean diameter of 0.92 ± 0.01 mm. Larvae hatched at 16 hrs post fertilization. The hatched larvae averaged 2.90 ± 0.16 mm in total length (LT). Complete yolk sac resorption and mouth opening occurred on the third day post hatching. At 45 days post hatching, the larvae were 12.5 ± 1.60 mm LT and had reached the juvenile stage.
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