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        검색결과 88

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pasture formation and management are crucial to avoid yield reduction. This experiment aimed to examine the effects of tall fescue-centered mixed-seeding combinations on yield and vegetation changes in perennial pastures in the central region for two years, from September 2020 to October 2022. The treatments were arranged in three replications in a randomized block design: control (C), tall fescue-based mixture-1 (T-1), and tall fescue-based mixture-2 (T-2). The tall fescue (TF), orchard grass (OG), perennial ryegrass (PRG), Kentucky bluegrass (KBG), and white clover (WC) were used. The emergency rate of grasses (70.0 to 73.3%) did not differ among mixed seeding combinations. Overwintering rates (81.7 to 83.3%) were similar among treatments. The plant height of grasses was similar at each harvest date, with the highest height (86.2 cm) recorded in the second harvest of the first year, followed by that (58.4 cm) in the third harvest of the first year; it was least (38.9 cm) in the fourth harvest of the second year. There was no significant difference in the dry matter yield of grasses among the mixed seeding combination treatments in the first, third, or fourth harvests of the first year (p>0.05). For second-year grasses, dry matter yield was not significantly different in harvest date among the treatments (p>0.05). Based on mixed seeding ratio, orchard grass showed the highest yield at 70% in the C treatment, followed by tall fescue at 80% and 60% in the T-1 and T-2 treatments, respectively, in the first harvest after seeding. There was no significant difference in feed value between treatments (p>0.05), but a significant difference was observed between the third and fourth harvest (p<0.05). Therefore, it indicated that it is important to create perennial pastures in the central region through mixed seeding combinations centered on tall fescue.
        4,000원
        2.
        2023.11 구독 인증기관·개인회원 무료
        To address the pressing societal concern in Korea, characterized by the imminent saturation of spent nuclear fuel storage, this study was undertaken to validate the fundamental reprocessing process capable of substantially mitigating the accumulation of spent nuclear fuel. Reprocessing is divided into dry processing (pyro-processing) and wet reprocessing (PUREX). Within this context, the primary focus of this research is to elucidate the foundational principles of PUREX (Plutonium Uranium Redox Extraction). Specifically, the central objective is to elucidate the interaction between uranium (U) and plutonium (Pu) utilizing an organic phase consisting of tributyl phosphate (TBP) and dodecane. The objective was to comprehensively understand the role of HNO3 in the PUREX (Plutonium Uranium Redox Extraction) process by subjecting organic phases mixed with TBPdodecane to various HNO3 concentrations (0.1 M, 1.0 M, 5.0 M). Subsequently, the introduction of Strontium (Sr-85) and Europium (Eu-152) stock solutions was carried out to simulate the presence of fission products typically contented in the spent nuclear fuel. When the operation proceeds, the complex structure takes the following form. 􀜷􀜱􀬶 􀬶􀬾(􀜽􀝍) + 2􀜰􀜱􀬷 􀬿(􀜽􀝍) + 2􀜶􀜤􀜲(􀝋􀝎􀝃) ↔ 􀜷􀜱􀬶(􀜰􀜱􀬷)􀬶 ∙ 2􀜶􀜤􀜲(􀝋􀝎􀝃) Subsequently, separate samples were gathered from both the organic and aqueous phases for the quantification of gamma-rays and alpha particles. Alpha particle measurements were conducted utilizing the Liquid Scintillation Counter (LSC) system, while gamma-ray measurements were carried out using the High-Purity Germanium Detector (HPGe). The distribution ratio for U, Eu (Eu-152), and Sr (Sr-84) was ascertained by quantifying their activity through LSC and HPGe. Through the experiments conducted within this program, we have gained a comprehensive understanding of the selective solvent extraction of actinides. Specifically, uranium has been effectively separated from the aqueous phase into the organic phase using a combination of tributyl phosphate (TBP) and dodecane. Subsequently, samples containing U(VI), Eu(III), and Sr(II) underwent thorough analysis utilizing LSC and HPGe detectors. Our radiation measurements have firmly established that the concentration of nitric acid enhances the selective separation of uranium within the process.
        3.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is widely known that forage corn is one of the most important crops in the production of silage and green chops during the summer months. In this study, the characteristics and the productivity of Kwangpyeongok, AGR 41, and Nero IT corn cultivars were evaluated in the regions of Jeju and Cheonan, Korea between 2021 and 2022. In each year, different corn cultivars were sown in different parts of the country on April 7 in Jeju and May 3 in Cheonan. The yield of three cultivars, Kwangpyeongok, AGR 41, and Nero IT were measured at the yellow-ripening stage, including the leaves and stems (Stover) and corn grain. Kwangpyeongok stover and total dry matter (DM) yields were slightly higher in Cheonan than in Jeju over the past two years. The quantity of corn cultivated in all cultivated areas was similar. The average yield of AGR 41, corn quantity and total DM were slightly higher in Jeju than in Cheonan. In terms of stover yield, and total dry matter content of the Nero IT cultivar cultivated in Jeju had a slightly higher yield than the cultivar cultivated in Cheonan. Based on this study, all cultivars can show some variations but not too much in terms of growth productivity and distinct characteristics depending on their location. Overall, AGR 41, and Nero IT cultivars in Jeju exhibit slightly higher levels of productivity than the same cultivars in Cheonan.
        4,000원
        4.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study sought to conduct a fundamental investigation in order to test and evaluate the thermal performance of an aluminum stick curtain wall system. In terms of the thermal performance index, the infiltration rate of air tightness, thermal transmittance of the heat insulation property and temperature difference ratio of condensation resistance were experimentally measured. The research process can be divided into three parts. First of all, a database for the test report of the curtain wall was compiled and existing design criteria with respect to the evaluation method and standard of transparent building components such as curtain wall, window and door were analyzed to produce the specimens. Secondly, four different types of curtain wall specimens were created through investigating the curtain wall database. Thirdly, standard tests of thermal performance were carried out for airtightness, thermal performance and condensation resistance. As a result, the curtain wall specimens with low-e triple glazing covered by an aluminum capture system showed high thermal performance compared to other curtain wall specimens including low-e triple glazing with a 4-sided structural sealant glazing system. Air tightness of all types of curtain wall specimens satisfied level 1 standard for air tightness. It was found that a curtain wall which consists of a one track frame has difficulties meeting the residential standard of thermal performance with regard to thermal transmittance and condensation resistance.
        4,300원
        5.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Livestock production costs are heavily influenced by the cost of feed, The use of domestically grown forages is more desirable for livestock feed production. As part of this study, triticale, which is an extremely palatable and easily cultivable crop in Korea, was used to produce low moisture silage bales with lactic acid bacteria (LAB) and then stored for different periods. We examined the nutrient content of silage, such as crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF), as well as their organic acids, including lactic acid, acetic acid, butyric acid, at different storage periods. The nutrient content of silages, such as crude protein, ADF, and NDF, did not change significantly throughout storage periods. Organic acid data indicated that lactic acid concentrations increased with increasing moisture contents and storage periods up to nine months. However, further extending storage to 12 months resulted in a reduction in the lactic acid content of all silages as well as an increase in their pH. Based on the present results, it suggested that the production of low moisture silage with the LAB may be able to preserve and maintain its quality without altering its nutritional composition. Also, the lactate content of the silage remained significant for at least nine months.
        4,000원
        7.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alfalfa is one of the most useful forage crops worldwide, containing a high level of amino acids that are essential to both human and animal health. However, amino acids and their concentrations may differ between plant parts. Hence, detecting amino acids in different plant parts would be useful in the development of diet supplements. The purpose of this study was to determine the amino acid content in alfalfa leaves, stems, and inflorescences using an amino acid analyzer. Asparagine and glutamic acid were the most abundant amino acids found in stems, leaves, and inflorescences than other amino acids. All parts of alfalfa had low concentrations of cysteine and methionine. All amino acids except asparagine were present in the highest concentration in leaves followed by inflorescences. Leaf had a rich amino acid content, namely asparagine, glutamic acid, leucine, proline, and lysine. However, the stem had a lower amino acid composition than the leaf or inflorescence. Overall, the data showed determining the amino acid content of forages provides a good approach to making animal feed with essential and specific amino acids and preventing excessive inclusion of amino acids.
        4,000원
        10.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the current study, lactic lactic acid bacteria (LAB) Lactobacillus plantarum and Pediococcus pentosaceus were used as a mixed additive for the production of Orchardgrass silage by ensiled method and nutritional change fermentation ability and microbial content of experimental silages. The addition of LAB to Orchardgrass during ensiling process rapidly reduced the pH of the silages than the non-inoculated silages. In addition, the lactic and acetic acid content of silage was increased by LAB strains than the non-inoculated silages whereas butyric acid content was reduced in silage treated with LAB. A microbiological study revealed that higher LAB but lower yeast counts were observed in inoculated silages compared to non-inoculated silage. Overall data suggested that the addition of LAB stains could have ability to induce the fermentation process and improve the silage quality via increasing lactic acid and decreasing undesirable microbes.
        4,000원
        14.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ensiling is the most preferred technology to preserve the silage quality with high nutrients by the presence of lactic acid bacteria. In this study, lactic acid bacteria RJ1 and S22 were used to make the silages from different leguminous plants such as alfalfa, hairy vetch and red clover. Experimental groups were divided into control and LAB inoculated groups. LAB inoculated group; all legumes treated with a mixture of RJ1 and S22 and made an anaerobic condition for 45d. Without the addition of LAB considered the control group. The results showed that the lactic acid content was higher in all silages in response to LAB treatment and acetic acid content was slightly increased except red clover by LAB compared to control silages. A poor silage quality marker butyric acid was reduced all legume silages in response to LAB inoculation than control silages. The organic acid is closely associated with microbial population experimental silages. We noted that higher LAB and lower yeast were found in the silage in response to LAB treatment. The contents of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and total digestible nutrient (TDN) were not altered significantly between control and LAB treated silages. Overall data suggested that the inclusion of additional LAB potentially enhance the silage quality and preserved the nutrients for long period.
        4,000원
        17.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Free-living nematodes feed on bacteria, algae, fungi, dead organisms, and living tissues. They release nutrients for plant use and improve soil structure and water holding capacity. They are usually the most abundant type of nematodes in soil and marine environments. This study has been conducted to survey the distribution and identification of soil nematodes from rhizosphere soil of plant for investigation of indigenous species according to Convention on Biological Diversity. Three species of free-living nematodes belonging to the order of Dorylaimida were found from paddy soil and soybean fields, Miryang, Gyeongsangnam-do and one species was found from soil, Dokdo island, Gyeongsangbuk-do, Korea. Aporcelaimellus obtusicaudatus, Eudorylaimus arcus and Mesodorylaimus spengelii are newly collected from Korea. A. obtusicaudatus can be recognized by its large body, short odontostyle being much thicker than cuticle at the same level, well developed gonads, shape and length of the tail. E. arcus is distinctive because of the wide lateral field, tail form and supplement arrangement. M. spengelii is smaller species with short odontostylet, simple guiding ring. Female tail more or less uniformly attenuated, tip is not swollen, nor curved dorsally.
        4,000원
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