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        검색결과 104

        4.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the forage characteristics of very early-maturing Italian ryegrass (IRG) three cultivars within September, 2021 to July, 2022 in Cheonan, Korea. We used three different cultivars of Italian ryegrass in this study “Greenfarm” “Greenfarm2ho” and “Greenfarm3ho” The results of heading date in this study, “Greenfarm” was recorded 3 days earlier than the other two cultivars, and its lodge tolerance score was the highest among the three. However, in case of plant length, there was no significantly difference in whole cultivars, in addition disease resistance, insect resistance and cold tolerance were not significantly different in three cultivars. The forage productivity of “Greenfarm2ho” was recorded the highest, especially the 1st harvesting of “Greenfarm2ho” yielded significantly the highest and superior to other varieties. As a result of feed value analysis, three cultivars were generally superior to overseas varieties and in particular, “Greenfarm2ho” was recorded to have excellent value because of the lowest NDF and ADF content. On the other hand, there was no significant difference in crude protein content among three varieties. In case of the monosaccharides content "Greenfarm3ho” had significantly higher glucose content than other two varieties, therefore the “Greenfarm” has advantage for preparing high quality of silage. In contrast, there was no significant difference among three varieties in fructose content.
        4,000원
        6.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 이탈리안 라이그라스를 벼 입모중 파종 후 벼 수확시기에 따른 이탈리안 라이그라스 극조생종 품종 ‘그린팜’ 의 생육특성 및 생산성을 평가하기 위해 중부지역에 위치한 천안에서 2011–2012, 2012–2013 및 2013–2014까지 3년간 수행하였다. 1. 국내육성 이탈리안 라이그라스 극조생종 ‘그린팜’을 3년 간 9월 하순에 파종 후 10일(처리 1), 20일(처리2) 및 30일(처리 3) 간격으로 3회에 나누어 벼를 수확해서 재배하였을 때, 벼 수확시기가 늦어질수록 월동 전 분얼수, 초장, 월동율 및 건물수량은 감소하는 것으로 나타났다. 2. 월동 전 분얼수는 처리 1에 비해 처리 2 및 3의 평균이 각각 32% 및 52% 감소하는 것으로 나타났다. 3. 벼 수확 지연에 따른 월동율의 경우 처리 1에 비해 처리 2 및 3은 두 처리구 모두 평균 8% 감소하였으며, 건물수량은 각각 평균 32% 및 52% 감소하였다. 4. 벼 입모중 이탈리안 라이그라스 파종 재배시험에서 출수기는 매년 다르게 나타났으며, 봄철 이탈리안 라이그라스 수확 시 초장의 차이는 유의성이 있는 차이를 보이지 않았다. 5. 논에서 입모중 파종으로 극종생 이탈리안 라이그라스 품종 그린팜을 재배할 때는 파종 후 가능한 한 빨리 벼를 수확하여 생산성을 높이는 것이 방법임을 시사한다.
        4,000원
        8.
        2021.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The decrease in under keel clearance (UKC) due to the increase of draft that occurs during advancing and turning of very large vessels of different types was analyzed based on computational fluid dynamics (CFD). The trim change in the Duisburg test case (DTC) container ship was much smaller than that of the KRISO very large crude oil carrier 2 (KVLCC2). The sinkage of both ships increased gradually as the water depth became shallower. The amount of sinkage change in DTC was greater than that in KVLCC2. The maximum heel angle was much larger for DTC than for KVLCC2. Both ships showed outward heel angles up to medium-deep water. However, when the water depth became shallow, an inward heel was generated by the shallow water effect. The inward heel increased rapidly in very shallow water. For DTC, the reduction ratio was very large at very shallow water. DTC appeared to be larger than KVLCC2 in terms of the decreased UKC because of shallow water in advancing and turning. In this study, a new result was derived showing that a ship turning in a steady state due to the influence of shallow water can incline inward, which is the turning direction.
        4,300원
        9.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The International Maritime Organization(IMO)는 2020년 1월 1일부터 국제항해 선박에 사용되는 모든 연료의 황분을 0.5 % 이하로 제한하고 있다. 연료유 황 함유량 규제 대응을 위해 LNG 선박, SOx scrubbers, 저유황유(Very Low-Sulfur Fuel Oil, VLSFO) 사용 등이 고려되고 있으며, 이 중 투자비용이 상대적으로 적은 저유황유가 선호되고 있다. 따라서 저유황유를 사용하는 선박이 증가함에 따라 오염사고 위험성이 높아질 것으로 예상된다. 특히, 해수 온도가 저유황유의 유동점 이하로 유출될 경우 고형화됨에 따라 방제에 어려움을 겪고 있는 사례도 나타나고 있다. 본 논문에서는 국내서 생산되는 저유황유 6종과 고유황유(MF380) 1종에 대해 해수 온도 조건에 따라 유처리제의 분산 능력을 평가하였다. 연구결과, 저유황유는 국내 기준(0.5 min 정치 60 % 이상, 10 min 정치 20 % 이상)을 만족하지 못했으며, 고유황유에 비해 상대적으로 낮은 유화율을 보였다. 본 연구결과는 저유황유가 해상에 유출될 경우, 방제방향을 설정하는 데 활용될 수 있을 것으로 기대된다.
        4,000원
        10.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국제해사기구(IMO)의 황함유량 규제에 따르는 저유황연료유는 생산 공정에 따라 다양한 물리화학적 특성을 가지게 된다. 본 연구는 저유황연료유 및 저유황-고유황 혼합연료유의 물리화학적 특성연구 결과를 해양오염 방제대응의 기초자료로 활용하고자 한다. 연구에 사용된 혼합연료유는 황함유량이 0.46 mass%인 저유황연료유와 0.36 mass%인 저유황연료유에 고유황연료유를 25, 50, 75 mass% 혼합하여 제조하였다. 이 혼합연료유에 대해 동점도, 유동점 및 Saturates, Aromatics, Resins, Asphaltenes(SARA)분포 등 물리화학적 특성에 대해 실험실 연구를 하였다. 동점도가 높고 유동점이 낮은 특징의 고유황연료유가 75 mass% 혼합함에 따라, 혼합연료유의 동점도는 350.2 %까지 증가 하였으며, 유동점이 23℃와 -11℃의 저유황연료유는 각각 -3℃ 및 -6℃까지 유동점이 내려가거나 올라갔다. Asphaltenes 분포가 적은 저유황연료유에 고유황연료유를 혼합함에 따라, Saturates분포는 68.8 %까지 감소하고, Asphaltenes분포는 1,417 %까지 크게 증가하였다.
        4,000원
        14.
        2020.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        At q = 1.81 ± 0.20 × 10-5, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio q of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent "pile-up" at q = 5-10 ×10-5. The event was observed by Spitzer, yielding a microlens-parallax πE measurement. Combined with a measurement of the Einstein radius θE from finite-source effects during the caustic crossings, these measurements imply masses of the host Mhost = 1.14+0.10-0.12 M⊙ and planet Mplanet = 7.59+0.75-0.69 M⊕, system distance DL = 3.38+0.22-0.26 kpc and projected separation a⊥ = 4.27+0.21-0.23 AU. The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.
        5,200원
        16.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the use of the amplifier very in high school English textbooks and native corpora by comparing its frequency distributions and collocation patterns. The native corpora, used as the reference of the study, were COCA and BNC, with their built-in sub-corpora further grouped into spoken and written corpora. The High School English Textbook Corpus (HSETC) was compiled from a total of 53 high school textbooks, with the spoken corpus (HSETC-S) from the texts in listening and conversation and the written corpus (HSETC-W) from the reading passages. Analyses using AntConc3.4.4 revealed no prominent differences between HSETC and reference corpora in the frequency of the amplifier very, while the written corpus (HSETC-W) had more occurrences contrary to the native corpora. The combination patterns and their occurrences of HSETC were slightly different from those of COCA and BNC with the gap increased with the spoken corpus (HSETC-S). Pedagogical implications and suggestions are made on ELT materials development and teaching practices.
        6,100원
        17.
        2018.05 구독 인증기관·개인회원 무료
        In this paper the authors would like to present and share the measurements of load spectra and their modelling for pavement design purposes in the Mexican road network, which due to the intense level of trade with the United States present a very high percentage of heavy vehicles in the flow of vehicles and with high levels of load. Examples of these measurements are given in the country's main transport corridors. Damage spectra are also presented that are associated to each of the different axle types (i.e., single, dual, tandem, tridem or another one) by computing for instance the Miner damage coefficient in the same load ranges used in the definition of the load spectra. Is this frequency distribution of the Miner damage coefficient that is called damage spectra. The damage spectra seem to be a very useful tool to evaluate the pavement expected damage, i.e., rutting or fatigue cracking, induced for a given axle type. Moreover, it can be showed that there is a direct relationship between the forms in load and damage spectra. Some examples are presented to illustrate the damage spectra computations. The incorporation of these load spectra into mechanistic design methodologies and their implications in the definition of public policies for the preservation of the road network are discussed.
        18.
        2018.05 구독 인증기관·개인회원 무료
        In this thesis, it was considered that in durability characteristics of concrete pavements evaluation of strength characteristics as well as abrasion resistance is important as the domestic concrete pavements couldn't fulfill the public needs and cases of damage are increasing. In order to solve such problems, it is intended to compare the abrasion resistance in accordance with the mixing rate of admixtures (silica fume and polymer powder) which are incorporated in the upper layer of two-lift concrete pavement and find the optimum mixing rate for abrasion resistance by focusing on the high performance of concrete pavements through two-lift concrete pavements which use cellular sprayed concrete construction method. Both test results, which were performed based on ASTM C 779 B (dressing wheel abrasion test method) and ASTM C 944 (rotary cutter method) standards in accordance with silica fume and polymer powder mixing rate that was incorporated in the upper layer of two-lift concrete pavement, proofed that the abrasion resistance increased as the mixing rate of silica fume and polymer powder increased. However, it was also confirmed that if the mixing rate of admixtures is excessively increased it will not have an effect and it will rather decrease the abrasion resistance.
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