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        검색결과 2,498

        181.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Korea has numerous astronomical resources, such as observational records, star maps, and a wealth of literature, covering the period from the Three Kingdoms (54 BC - 932 AD) to the Joseon Dynasty (1392 - 1910 AD). The research activities related to these resources have been limited to those by individual researchers. It is now necessary to conduct research by efficiently and systematically collecting and managing Korean astronomical records using an accessible Web environment. The purpose of this study is to complete a system that enables researchers systematically to collect and verify a large number of historical records related to astronomical phenomena in a Web environment. In 2017, a preliminary survey was conducted, and the requirements pertaining to an implementation target system were devised. In addition, a joint development plan was carried out by the developer, lasting three months in 2018. Although the system is relatively simple, it is the first system to be attempted in the historical astronomy field. In order to proceed with the systematic development, the software development methodology is applied to the entire process from deriving the requirements of researchers to completing the system. The completed system is verified through integrated function and performance tests. The functional test is repeated while modifying and testing the system based on various test scenarios. The performance test uses a performance measurement test tool that takes measurements by setting up a virtual operation environment. The developed system is now in normal operation after a one-year trial period. Researchers who become authorized to use the system can use it to verify the accuracy of data and to suggest improvements. The collected feedback will be reflected in future systems, and Korean astronomical records will be available for use internationally through a multilingual service.
        4,500원
        182.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 충청남도 보령시에 위치한 보령호를 대상으로 어류상 및 붕어 개체군의 특성을 파악하고자 2017년 10월부터 2018년 6월까지 조사를 실시하였다. 어류상 조사결과, 총 9과 15종 3,506개체가 출현하였으며, 한국고유종은 얼룩동사리 1종 (6.6%), 외래종 및 생태계교란종은 떡붕어, 배스 2종 (13.3%)이 조사되었다. 상대풍부도 분석결과, 빙어 1,706개체 (48.6%), 붕어 1,021개체 (29.1%)로 각각 우점, 아우점하고 있는 것으로 나타났다. 생체량 분석결과 붕어가 246,130 g으로 가장 높은 생체량을 보였으며, 동자개 50,610 g, 떡붕어 14,730 g, 메기 11,560 g, 잉어 10,930 g의 순으로 분석되었다. 군집분석 결과 우점도지수 0.87 (±0.2), 다양도 지수 0.78 (±0.5), 균등도지수 0.47 (±0.2), 풍부도지수 0.99 (±0.5)로 분석되었다. 붕어 개체군의 전장 - 체중 상관관계 분석결과 회귀계수 b값은 3.06으로 나타났으며, 비만도 지수 (K) 기울기는 양의 기울기로 분석되었다. 전장빈도분포 분석결과, 당년생은 출현하지 않았으며, 2년생으로 추정되는 170~190 mm 개체는 다수 출현하였고, 4~5년생으로 추정되는 230~280 mm 개체는 낮은 출현을 나타내었다. 보령호의 저수량 추이를 확인하기 위해 연평균저수량과 NDWI 분석을 실시한 결과, 2013년에서 2014년에 급격한 연평균 저수량 변화를 나타내었으며, 웅천천이 유입되는 St. 4에서 수위변동에 영향을 받는 것으로 추정되었다.
        4,200원
        183.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The most important thing to successfully restore an oak forest is finding suitable climatic conditions and topographic factors for the oak species to be introduced. In this study, in order to find suitable environmental conditions for the five dominant oak trees on the Korean Peninsula, we carried out analysing the information on the location of forest vegetation on the Korean Peninsula. The range of annual mean temperature of the five oak trees was narrow in the order of Q. mongolica (7.7~14.3°C), Q. variabilis (9.2~13.8°C), Q. acutissima (10.5~14.3°C), Q. serrata (11.4~13.7°C), Q. aliena (11.0~12.9°C). The range of annual precipitation of oaks was narrow in order of Q. mongolica (1072.7~1780.9 mm), Q. variablis (1066.6~1554.9 mm), Q. acustissima (1036.5~1504.8 mm), Q. serrata (1062.6~1504.7 mm). The range of altitude was in order of Q. mongolica (147~1388 m), Q. serrata (93~950 m), Q. variabilis (90~913 m), Q. acustissima (60~516 m), Q. aliena (55~465 m). The range of slope was in the order of Q. mongolica (8~56°), Q. variabilis (5~52°), Q. serrata (11~45°), Q. aliena (15~38°), Q. acustissima (16~37°). These results are considered to be very useful in the case of ecological restoration using deciduous oak trees on the Korean Peninsula.
        4,000원
        184.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to investigate the effect of environmental temperature and backfat thickness (BT) on the reproductive performance of lactating sows. Sixty crossbred sows were allotted to four groups in a 2×2 factorial arrangement by environmental temperature (high temperature [HT], 27.5±1.76℃; low temperature [LT], 23.3±0.89℃) and BT (<20 mm, average 17.70 mm; ≥20 mm, average 23.20 mm) from July to August 2019. Sows in the HT group experienced a greater change in BT and a lower feed intake. Losses in body weight and BT were lower in sows with <20 mm BT than in those with ≥20 mm BT. Sows with low BT had a lower weaning-to-estrus interval than sows with high BT (5.20, 4.93 d vs. 5.87, 5.60 d, respectively). Piglet survivability was lower in the HT group (90.31%) than in the LT group (94.87%). Piglet weaning weight and average daily weight gain were greater in sows with <20 mm BT (5.75 kg and 201.46 g, respectively) than in those with ≥20 mm BT (5.49 kg and 188.41 g, respectively). Sows in the HT group had higher cortisol concentrations than those in the LT group (post-farrowing: HT 7.86 μg/mL vs. LT 6.04 μg/mL; weanling: HT 5.48 μg/mL vs. LT 4.40 μg/mL). In conclusion, environmental temperature adversely influenced sow performance and cortisol levels. Moreover, sows with low BT had a greater weaning-to-estrus interval when subjected to heat stress.
        4,000원
        193.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to examine the effects of Atractylodes lancea (A.l.) in a dose-dependent manner on lipid levels and plasma glucose in diabetic rats induced with streptozotocin (STZ). The Sprague-Dawley rats were randomly classified into five groups: normal, STZ-control and three experimental groups [A.l.-1, diabetic treated with ethanolic extract of A.l. (1 g/kg b.w.), A.l.-2, diabetic administered with ethanolic extract of A.l. (2 g/kg b.w.), and A.l.-3, diabetic administered with ethanolic extract of A.l. (3 g/kg b.w.)]. The normal and STZ-control group were fed an AIN-93 diet and the three experimental groups were administered with A.l. extract at doses of 1, 2, and 3 g/kg b.w./day, respectively, for 14 days. The plasma glucose levels in all the experimental groups were significantly lower than the STZ-control group after 14 days of treatment. The total cholesterol of the A.l.-3 and triglyceride levels, atherogenic index (AI) of all three experimental groups were significantly lower than the STZ-control group. The ALT and AST activities at A.l.-2, A.l.-3 were significantly lower than the STZ-control group. This result that demonstrate the administration of Atractylodes lancea can reduce hyperglycemia and hyperlipidemia risk in diabetic rats.
        4,000원
        194.
        2020.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Organic-inorganic hybrid perovskite nanocrystals have attracted a lot of attention owing to their excellent optical properties such as high absorption coefficient, high diffusion length, and photoluminescence quantum yield in optoelectronic applications. Despite the many advantages of optoelectronic materials, understanding on how these materials interact with their environments is still lacking. In this study, the fluorescence properties of methylammonium lead bromide (CH3NH3PbBr3, MAPbBr3) nanoparticles are investigated for the detection of volatile organic compounds (VOCs) and aliphatic amines (monoethylamine, diethylamine, and trimethylamine). In particular, colloidal MAPbBr3 nanoparticles demonstrate a high selectivity in response to diethylamine, in which a significant photoluminescence (PL) quenching (~ 100%) is observed at a concentration of 100 ppm. This selectivity to the aliphatic amines may originate from the relative size of the amine molecules that must be accommodated in the perovskite crystals structure with a narrow range of tolerance factor. Sensitive PL response of MAPbBr3 nanocrystals suggests a simple and effective strategy for colorimetric and fluorescence sensing of aliphatic amines in organic solution phase.
        4,000원
        195.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        아이치 생물다양성 목표11을 달성하기 위하여, 국내 보호지역은 양적으로 꾸준히 증가되어왔으며, 추가 지정이 필요한 잠재 보호지역에 대한 연구도 진행되어왔다. 하지만 효과적인 생물다양성 보전을 위한 보호지역의 상보성에 대한 평가는 미흡하다. 본 연구에서는 제3차 전국자연환경조사의 식물종을 대상으로 종분포모형을 이용하여 잠재서식지역을 도출하고, 기존 보호지역과 잠재보호지역 내 잠재서식지역이 포함되는 종의 풍부도를 유사도 지수인 Jaccard, Sorenson, Bray-curtis를 이용하여 비교분석하였다. 연구결과로 기존 보호지역과 잠재보호지역 대부분이 상보성이 낮아 유사한 식물종을 보전하는 것으로 나타났다. 국립수목원 완충지역이 상보성이 높아 보호지역으로서의 가치가 높다고 할 수 있다. 잠재서식지역이 포함되 는 경우가 적은 식물종을 보호하기 위해서는 기존 또는 잠재 보호지역 외 지역에 추가로 보호지역을 선정할 필요가 있음을 확인할 수 있었다. 본 연구는 개별 보호지역이 보호지역으로서 고유한 생태계 또는 생물종 보전이 가능한지 각 보호지역의 생태적 대표성을 확인하고, 공간적으로 추가 보호가 필요한 지역을 탐색하는 방법을 제안했다는 점에서 의의가 있으며, 향후 동물종까지 포함한 상보성 평가를 통한 보호지역의 질적 개선과 계속적으로 조사되는 전국자연환경조사 자료를 이용한 보호지역의 효과성평가 연구 등으로 발전시킬 수 있을 것으로 판단된다.
        4,000원
        196.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Additive manufacturing technology is recognized as an optimal technology for mass-customized distributed production because it can yield products with high design freedom by applying an automated production system. However, the introduction of novel technologies to the additive manufacturing industry is generally delayed, and technology uncertainty has been pointed out as one of the main causes. This paper presents the results of the research and analysis of current standardization trends that are related to additive manufacturing by examining the hierarchical structure of the quality system along with the various industry and evaluation standards. Consequently, it was confirmed that the currently unfolding standardization does not sufficiently reflect the characteristics of additive manufacturing technology, and rather can become a barrier to entry for market participants or an element that suppresses the lateral shearing ability of additive manufacturing technology.
        4,000원