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        검색결과 7

        1.
        2022.05 구독 인증기관·개인회원 무료
        Deep geologic repositories (DGR) are designed to store spent nuclear fuel and to isolate it from the biosphere for an extended period of time as long as millions of years. The long-term performance of the DGR replies on the performance of the natural geologic barriers after the end of the lifetime for the engineered barrier systems. Typically, multiple analytical and numerical models are used to analyze and ensure the safety of the repositories along both engineered and natural barrier systems. Despite the immense advancement in computing power and modeling techniques over the last few decades, a series of models and their linkage often require many simplifying assumptions in this safety assessment. The degree of the reliability and confidence of the safety analysis is thus highly dependent on the validity of those tools used. Considering the significance of the DGR performance and public attention, the highest level of quality control is necessary for the models employed in the assessment. The performance of the ultimate long-term geologic barrier is determined by the expected travel time of the radioactive species of interest, the level of their dilution or radioactivity at compliance areas, and the uncertainty associated with them. As the species of interest can be carried away from the repository location by groundwater flow, the travel time is determined by groundwater velocity along the flow path from source to biosphere while the dilution is a function of the decay and production rates as well as the diffusion and dispersion. Due to the time scale and the complexity of the physicochemical processes and geologic media involved, the models used for safety evaluation will need to become more and more comprehensive, robust, and efficient which is difficult to achieve in principle. They will also need to be transparent and flexible to satisfy the regulatory quality control requirements. This study thus attempts to develop an accessible, transparent, and extensible integrated hydrologic models (IHM) which can be widely accepted by the regulators as well as scientific community and thus suitable for current and future safety assessment of the DGR systems. The IHM can be considered as a tool and a framework at the same time when it is designed to easily accommodate additional processes and requirements for the future as it is necessary. The IHM is capable of handling the atmospheric, land surface, and subsurface processes for simultaneously analyzing the regional groundwater driving force and deep subsurface flow, and repository scale safety features, providing an ultimate basis for seamless safety assessment in the DGR program. The applicability of the IHM to the DGR safety assessment is demonstrated using simple illustrative examples.
        2.
        2014.06 구독 인증기관·개인회원 무료
        Ganoderma lucidum has a long history for traditional medicine in Asian countries. However, taxonomy of Ganoderma species remains controversial, since it was initially classified on the basis of morphological characteristics. Recently, Ganoderma sichuanense was proposed as a re-proposed name for Ganoderma lucidum in China. Likewise, all of the Korean G. lucidum were clustered into 1 group together with G. sichuanense from China, when a phylogenetic analysis was undertaken based on the ITS rDNA sequences of the Ganoderma species. Furthermore, G. lucidum from Europe and North America were clustered into different group. Based on these results, re-consideration of naming Korean cultivated G. lucidum is needed.
        3.
        2013.11 구독 인증기관·개인회원 무료
        In the present study, the genetic diversity of 69 Ganoderma species from various regions was determined by different molecular markers, including the internal transcribed spacer (ITS) rRNA, a partial β-tubulin gene, and mitochondrial small-subunit ribosomal (SSU) rDNA gene as well as randomly amplified polymorphic DNA (RAPD) analysis. The size of the ITS rDNA regions and mitochondrial SSU rDNA gene from different Ganoderma species varied from 625 to 673 bp and 656 to 2,040bp, respectively, and those of the partial β-tubulin gene sequence were 419 bp. Phylogenetic analysis based on the ITS region, the partial β-tubulin gene, and the mitochondrial SSU rDNA gene reveal that Ganoderma species are largely divided into two groups. Interestingly, most of the Ganoderma lucidum strains could be classified into 1 group, while other Ganoderma species divided into several groups (4 or 5 groups) in phylogenetic tree. One fragment unique to G. lucidum was selected from the RAPD profile and then sequenced. One primer pair (designated as KGS-F and KGS-R) based on this specific fragment was designed to amplify a 559 bp DNA fragment within the sequenced region. A single band with the expected size of 559 bp was observed from G. lucidum, except for G. lucidum strains from China, Canada, and Taiwan. This specific marker for G. lucidum from RAPD analysis, also supported by the phylogenetic analysis of the ITS, partial β-tubulin gene, and mitochondrial SSU rDNA sequences, will be useful for the PCR-based identification of G. lucidum in research applications as well as in the market.
        4.
        2013.07 서비스 종료(열람 제한)
        Doubled haploid system is a very effective tool which has been widely applied in wheat breeding programmes. Wide-hybridization, wheat X maize cross, is used for the production of wheat doubled haploids (DH). The introduction of doubled haploid (DH) approach into breeding programs has reduced the times and population sizes required for the production of pure lines. We carried out the experiment for development on effective method of producing haploid in wheat. Emasculated spikelets of wheat were pollinated with maize pollen and cultured in the solution containing 40 g/ℓ sucrose and 2,4-D, ABA and GA3 24 h after pollination, and then incubated until embryo rescue. twelve to fourteen days after pollination, the embryos are excised and cultured in half-strength MS basal medium supplemented with 20 g/ℓ sucrose and 1 ㎎/ℓ NAA. The type of plant growth regulators was found to be most significant in production of haploid plants. The application of synthetic auxins to pollinated florets, stimulates haploid embryo development to a stage where the embryos can be rescued onto nutrient media. The percentage of embryos formed was significantly affected by 100 ㎎/ℓ 2,4-D plus 50 ㎎/ℓ BAP and 100 ㎎/ℓ 2,4-D plus 50 ㎎/ℓ GA3. There was varied efficiency in embryo formation from 5.7 to 53%.
        5.
        2012.07 서비스 종료(열람 제한)
        ‘Jungmo2502’ awnless barley line (Hordeum vulgare L.) developed at National Institute of Crop Science, RDA in 2011. The Jungmo2502 derived from three-way cross between Millyang100 and F1 (Samheung/Suwon300) in 2000. Subsequent generation were handled by the bulk method in a pedigree selection program. A promising line showed high yield as well as lodging resistance in the yield trial tested at Iksan in 2007 to 2008, designated as Iksan 448. The line in the regional yield trials(RYT) tested in seven locations around Korea for three years from 2009 to 2011. The Jungmo2502 is carrying the growth habit of Ⅳ, green leaf and stem similar to the check cultivar ′Youngyang′. Its heading date was May 3, and maturing time was May 30 in paddy field, which was 3 days later respectively than check cultivar. It was 98 cm of culm length, 607 spikes per m2 and showed more rate of leaf blade, winter hardiness, and resistance to BaYMV than the check cultivar. Average dry matter yield was similar with the check cultivar in paddy field (about 11 ton ha-1). It also showed good qualities as 8.7% of crude protein, 21.9% of ADF (acid detergent fiber), 40.7% of NDF (neutral detergent fiber), and 71.6% of TDN (total digestible nutrients), including high grade of silage for whole crop barley.
        7.
        2001.09 KCI 등재 서비스 종료(열람 제한)
        Water deficit is a serious constraint to soybean [Glycine max L. (Merr.)] production in rainfed regions of Asia, Africa, and America. This study was conducted to develop a simple and effective screening method for drought tolerance in soybean. Fifteen soybean cultivars, eight identified to be drought-tolerant and seven drought-sensitive in previous studies, were used for the evaluation of drought tolerance under the new screening conditions. The seedling screening method was consisted of a treatment in a PEG solution and drought treatment in parafilm-layered pots. 5-day-old seedlings were treated in a 18% PEG solution for 4 days and their wilting and hypocotyl browning were recorded. Three seedlings grown in a parafilm-layered pot containing peat moss were drought-stressed by withholding water from the third day after seedling emergence, and root and seedling growth were examined. Degree of drought tolerance were rated based on seedling vigor in the PEG solution and drought-stressed parafilm-layered pots, and also on the penetration ability of roots through parafilm layer. Most of seedlings of the drought-tolerant cultivars showed higher vigour and root penetration than those of the drought-sensitive cultivars under the new screening conditions. Our results indicate that the new method can be used as a simple and effective screening procedure for drought tolerance in soybean breeding programs.