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        검색결과 5

        2.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The domestic catch of squid is decreasing every year. Import volume is increasing to replace these domestic products. Import volume is expected to increase in the future, so it is necessary to study import substitution. Therefore, in this study, after selecting frozen squid, which accounts for the majority of imported squid, as the target fish species, China, Chile and Peru, which account for the majority of frozen squid imports, will be selected as the target countries for analysis. Then, the demand function of squid is estimated using the Rotterdam model, the inverse Rotterdam model, AIDS and inverse AIDS, which are the simultaneous equation demand types, and then elasticity is derived. After that, these models are compared in terms of significance, theoretical fit and practical fit.
        5,200원
        3.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, an ASR-reducing (alkali-silica reaction) cement was developed to prevent the blow-up of concrete pavements. To develop ASR-reducing cement, various amounts of ground granulated blast furnace slag (GGBFS), and fly ash (FA) were substituted with Portland cement, and the ASR reduction effect was verified through various experiments. METHODS : The physical properties of ASR-reducing cement, varying with the substitution amounts of GGBFS and FA, were verified through compressive strength tests. In addition, the ASR reduction effect was examined using accelerated mortar bar tests. Furthermore, the reasons for the ASR reduction were investigated using microstructural analysis techniques, such as XRD and TG/DTG. RESULTS : There was a difference in the compressive strength results according to the amount of GGBFS and FA substitution. In addition, the samples with GGBFS and FA exhibited relatively lower compressive strengths at 3 days, than OPC samples, but the compressive strength at 28 days was higher than that of the OPC samples. The samples with GGBFS and FA had higher compressive strength at 28 days than OPC samples, because the substituted GGBFS and FA induced pozzolanic reaction. Through XRD and TG/DTG analyses, various degrees of pozzolanic reaction occurring in the samples were examined, and a more active pozzolanic reaction occurred in the samples with FA than in the samples with GGBFS. Therefore, it appeared that the ASR reduction effect occurred because of the induced pozzolanic reaction. CONCLUSIONS : GGBFS and FA substituting Portland cement indicated an ASR reduction effect, which was owing to the pozzolanic reaction. In addition, FA indicated a greater ASR reduction effect than GGBFS, which suggested that FA induced a more active pozzolanic reaction than GGBFS.
        4,000원
        4.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electric night storage heater was introduced and disseminated for power grid balancing and efficient management of power generation facility. But fuel cost for heating has been increased rapidly while the cost of electricity increased slightly. This abnormal rate system caused peak load in winter at last. To solve this problem, application of an air source heat pump was suggested. In the study, the effect of replacing night heater by heat pump and the economics were analysed. In addition the expectation of prospect of heat pump penetration was simulated based on surveyed and investigated data. As a result, fund supporting as well as institutional backing was needed for effective propagation and return of investment.
        4,000원
        5.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        Chromosome segment substitution lines (CSSLs), in which each line carries a single or a few defined chromosome segment of donor genome and has a pure genetic background from a recurrent genotype, is a fundamental approach to conduct the QTL mapping in order to improve the mapping precision. In the present study, variety ‘ZM36’ (Gossypium. hirsutum) and ‘Hai1’ (Gossypium. Barbadense) were used as recurrent and donor parent to produce a segment substitution lines populations, respectively. The results indicated that most of fiber quality traits, yield-related traits and verticillium wilt traits fit the normal distribution in the Kolmogorov-Smirnov test. In 133 lines of BC4S2:3 generation fiber length longer the recurrent parent has 37, micronaire lower than the recurrent parent has 58, Fiber strength over than the recurrent parent has 34. In 199 individuals of BC4S2:4 generation fiber length longer the recurrent parent has 37, micronaire lower than the recurrent parent has 36, Fiber strength over than the recurrent parent has 49. Fiber length had significantly positive correlation with fiber strength and negative correlation with micronaire, seed index had significantly positive correlation with boll weight and negative correlation with lint percentage, lint percentage had negative correlation with fiber length and strength.