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        검색결과 2,644

        170.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 복분자에서 분리된 Lactobacillus plantarum stain (GBL16 및 17)을 포함한 probiotic에 대해 수행되었으며, 장내 미생물 변화를 확인하였다. Balb/c 마우스모델에서 GBL 16, 17을 포함한 시제품인 PMC와 시판중인 유산균 과자 BFY를 8주간 경구 투여 하였다. PMC의 투여는 장내 미생물총의 균형을 향상시키고, 장내개선에 긍정적인 영향을 보였다. 맹장을 이용한 NGS 분석을 통해 확인한 결과, 스트레스 후 증가하는 양상을 보이는 균인 Lachnospiraceae균이 감소하는 경향을 보였다. Alistipes균의 증가는 염증성 장 질환에 효과가 있을 것으로 판단되나, 추후 더 많은 연구가 필요할 것으로 보인다.
        4,000원
        171.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study is to analyze the impact of the level of the light-environment and the driver's visual ability on the change in the driver's perception of a forward curved section at night. The study also aims to identify factors that should be considered to ensure safety while entering curved sections of a road at night. METHODS : Data collected from a virtual driving experiment, conducted by the Korean Institute of Construction Technology (2017), were used. Logistic regression was applied to analyze the effects of changes in the light-environment factors (road surface luminance and glare) and the driver’s visual ability on a driver's perception of the road. Additionally, analysis of the moderated effect of visual ability on light-environment factors indicated that the difference in drivers’ visual abilities impact the influence of light-environment factors on their perception. A driver's ability to perceive, as a response variable, was categorized into 'failure' and 'success' by comparing the perceived distance and minimum reaction sight distance. Covariates were also defined. Road surface luminance levels were categorized into 'unlit road surface luminance' (luminance ≤ 0.1 nt) and 'lit road surface luminance' (luminance > 0.1 nt), based on 0.1 nt, which is the typical level observed on unlit roads. The glare level was categorized as 'with glare' and 'without glare' based on whether the glare was from a high-beam caused by an oncoming vehicle or not. The driver's visual ability level was categorized into 'low visual ability' (age ≥ 50) and 'high visual ability' (age ≤ 49), considering that after the age of 50, the drive’s visual ability sharply declines. RESULTS : The level of road surface luminance, glare, and driver's visual ability were analyzed to be significant factors that impact the driver's ability to perceive curved road sections at night. A driver's perception was found to reduce when the road surface luminance is very low, owing to the lack of road lighting ('unlit road luminance'), when glare is caused by oncoming vehicles ('with glare'), and if the driver's visual ability level is low owing to an older age ('low visual ability'). The driver's ability to perceive a curved section is most affected by the road surface luminance level. The effect is reduced in the order of glare occurrence and the driver's visual ability level. The visual ability was analyzed as a factor that impacts the intensity of the effect of change of the light-environment on the change of the driver's ability to perceive the road. The ability to perceive a curved section deteriorates significantly in 'low visual ability' drivers, aged 50 and above, compared to drivers with 'high visual ability,' under the age of 49, when the light-environment conditions are adverse with regard to the driver’s perception (road surface luminance: 'lit road surface luminance'→'unlit road surface luminance,' glare: 'without glare'→'with glare'). CONCLUSIONS : Supplementation, in terms of road lighting standards that can lead to improvements in the level of light-environment, should be considered first, rather than the implementation of restrictions on the right of movement, such as restricting the passage of low visual ability or aging drivers who are disadvantageous in terms of gaining good perception of the road at night. When establishing alternatives so that safety on roads at night is improved, it is necessary to consider improving drivers' perception by expanding road lighting installation. The road lighting criteria should be modified such that the glare caused by oncoming traffic, which is an influential factor in the linear change in perception, and the level of light-environment thereof are improved.
        4,000원
        172.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study analyzes the characteristics of generated fine particulate matter (PM2.5) and nitrogen oxide (NOX) at roadsides using a statistical method, namely, a generalized linear model (GLM). The study also investigates the applicability and capability of a machine learning methods such as a generalized regression neural network (GRNN) for predicting PM2.5 and NOX generations. METHODS : To analyze the characteristics of PM2.5 and NOX generations at roadsides, data acquisition was conducted in a specific segment of roads, and PM2.5 and NOX prediction models were estimated using GLM. In addition, to investigate the applicability and capability of a machine learning methods, PM2.5 and NOX prediction models were estimated using a GRNN and were compared with models employing previously estimated GLMs using r-square, mean absolute deviation (MAD), mean absolute percentage error (MAPE), and root mean square error (RMSE) as parameters. RESULTS : Results revealed that relative humidity, wind speed, and traffic volume were significant for both PM2.5 and NOX prediction models based on estimated models from a GLM. In addition, to compare the applicability and capability of the GLM and GRNN models (i.e., PM2.5 and NOX prediction models), the GRNN model of PM2.5 and NOX prediction was found to yield better statistical significance for r-square, MAD, MAPE, and RMSE as compared with the same parameters used in the GLM. CONCLUSIONS : Analytical results indicated that a higher relative humidity and traffic volume could lead to higher PM2.5 and NOX concentrations. By contrast, lower wind speed could affect higher PM2.5 and NOX concentrations at roadsides. In addition, based on a comparison of two statistical methods (i.e., GLM and GRNN models used to estimate PM2.5 and NOX), GRNN model yielded better statistical significance as compared with GLM.
        4,000원
        174.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study reported on the phytoplankton community and seasonal changes in the Seoul passage section and downstream in the Han River in 2012. Field samples were collected monthly from the upper (Paldang), middle (Cheongdam), and downstream (Seongsan) areas of the Seoul passage section. Water temperature, DO, pH, and conductivity were measured at each station. All environmental factors measured were recorded similarly at the three stations. The water temperature ranged from 2 to 30°C and the dissolved oxygen ranged from 4.8 to 9.1 mg L-1, showing typical patterns of temperate regions. The phytoplankton cell concentrations ranged from 990 cells mL-1 (Paldang, December) to 2.9×104 cells mL-1 (Seongsan, March), and the chlorophyll-a content showed similar patterns to the cell numbers. The phytoplankton community was comprised of 75 genera and 95 species, including 37 diatoms, 29 Chlorophyta, 11 cyanobacteria, and two dinoflagellates. The number of species that appeared seasonally varied greatly, from nine species (Paldang, May) to 35 species (Cheongdam, December). Diatoms were the most dominant in all stations and seasons, except in summer. In contrast, chlorophytes and cyanobacteria showed sporadic high numbers in the summer and fall seasons. Four diatoms Stephanodiscus hantzschii f. tenuis, S. hantzschii, Fragilaria sp., and Aulacoseira spp., a chlorophyte Actinastrum hantzschii, and a cyanobacterium Microcystis sp. were each present in proportions greater than 10%. This study provides fundamental data from phytoplankton communities and environmental factors in the Han River for understanding water quality for long-term environmental monitoring.
        4,000원
        175.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A T-800 (Co-Mo-Cr) coating material is fabricated using Co-Mo-Cr powder feedstock and laser cladding. The microstructure and melted Al erosion properties of the laser-cladded T-800 coating material are investigated. The Al erosion properties of the HVOF-sprayed MoB-CoCr and bulk T-800 material are also examined and compared with the laser-cladded T-800 coating material. Co and lave phases (Co2MoCr and Co3Mo2Si) are detected in both the lasercladded T-800 coating and the bulk T-800 materials. However, the sizes of the lave phases are measured as 7.9 μm and 60.6 μm for the laser-cladded and bulk T-800 materials, respectively. After the Al erosion tests, the erosion layer thicknesses of the three materials are measured as 91.50 μm (HVOF MoB-CoCr coating), 204.83 μm (laser cladded T- 800), and 226.33 μm (bulk T-800). In the HVOF MoB-CoCr coating material, coarse cracks and delamination of the coating layer are observed. On the other hand, no cracks or local delamination of the coating layer are detected in the laser T-800 material even after the Al erosion test. Based on the above results, the authors discuss the appropriate material and process that could replace conventional bulk T-800 materials used as molten Al pots.
        4,000원
        176.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to analyze the characteristics of odorous components that have been generated from the downtown sewer system based on twenty-three survey items for complex odor and designated offensive odor. As a result of the research, the contribution rates for the causative materials of the odor indicated 73.5% of hydrogen sulfide, 26.0% of methyl mercaptan, 0.4% of dimethyl sulfide, and 0.1% of dimethyl disulfide. The occurrence for the odorous materials according to sampling site revealed data of which contribution rates showed 56.9% of hydrogen sulfide and 36.8% of methyl mercaptan from the combined sewer system in the business district; whereas the combined sewer system in the residential area showed 16.4% of dimethyl sulfide and 4.3% of dimethyl disulfide. The seasonal occurrence rate of the odor materials was observed higher in summer and lower in winter And, the combined sewer system in the business district recorded the highest concentration of 4.61 ppm of hydrogen sulfide among the sampling site. An hourly occurrence rate for the odor materials consistently showed the greatest increase between 11:00 and 14:00 at each location and showed a decreasing tendency afterward.
        4,000원
        177.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ‘Japonica 7’(Registration No. BPI-NSIC-2019-Rc 584)은 열대지역에 적응하는 고품질 다수성 자포니카 벼를 개발 하기 위하여 2020년 육성되었으며 육성 과정 및 주요 특성은 다음 과 같다. 1. ‘Japonica 7’은 열대지역 적응 고품질 자포니카 다수성 품종 육성을 목적으로 필리핀 소재 국제미작연구소 (IRRI)에서 농촌진흥청 파견 연구원 주도로 2012년 건기에 필리핀 국제미작연구소에서 ‘Japonica 2’와 ‘IR11K233’를 교배한 후 계 통육종법으로 육성된 품종이다. 2. 2012년 우기에 F1세대로 부터 얻은 종자를 이용하여 F6 세대까지 계통을 전개하는 과정에서 선발된 ‘IR101055-52-2- 1-2-2’ 계통을 대상으로 2017~2018년 2년간 우기 및 건기 각 2회 지역적응시험을 실시한 결과 그 우수성이 인정되어 2020 년에 필리핀 벼 품종심의위원회에서 장려품종으로 선정되고 ‘Japonica 7’으로 명명되었다. 3. ‘Japonica 7’은 파종부터 수확까지 생육일수가 111일인 조생종으로, 간장과 수장, 포기당 이삭수는 ‘MS 11’과 비슷하다. 등숙률은 89%로 ‘MS 11’보다는 낮은 편이나 ‘Japonica 1’ 보다는 높았다. 현미천립중은 23.3g으로 ‘MS 11’과 비슷한 중립중이다. 4. 병해충 반응은 도열병과 잎집무늬마름병 및 흰잎마름병 에는 중도저항성이나 퉁그로바이러스에는 약하다. 벼멸구와 애멸구에는 중도 또는 감수성이었으나 이화명충의 일종인 White stemborer에는 ‘MS 11’과 비슷하게 강한 편이다. 5. ‘Japonica 7’의 곡립은 중립종이고 완전미 도정수율이 58.8%로 ‘MS 11’보다 높았으며, 필리핀 소비자 선호도는 ‘Japonica 7’이 대비품종인 ‘MS 11’ 보다 쌀에서는 75.6%, 밥맛에서는 81.1%로 현저하게 높게 나타났다. 6. ‘Japonica 7’의 수량은 필리핀 지역적응시험 평균 3.03 MT/ha로 대비품종 ‘MS 11’보다 17% 높았으며 시험한 전지역에서 전반적으로 표준품종인 ‘MS 11’보다 전 지역에서 안정적으로 높은 수량을 나타냈다.
        4,000원
        179.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        2018년 6월 1일부터 9월 17일까지 109일 동안, 총 112개 국외 발 국내 입항 선박을 대상으로 편승자 해충(hitchhiker insect pests)에 대한 모니터링을 실시하였다. 그 결과, 총 336개체의 편승자 해충을 확보하였으며, 이를 통합 분류학적 종동정 방법(integrative identification method)을 이용하여 9목 47과 159종으로 동정하였다. 이 중 총 3목 9과 14종의 한국 미분포종(not-distributed species)이 확인되어 보고하며, 검출된 미분포종에 대해서 침입종(invasive species) 내지 침입 가능종(invasive likelihood species)에 대한 위험성 평가를 위한 data sheet를 제공하였다. 또한, 미기록(unrecorded species), 미보고종(unreported species) 내지 신기록종(new recorded species)과 용어의 혼동을 피하기 위하여 본 연구에서는 미분포종(not-distributed species)을 제안하여 사용하였다.
        4,200원
        180.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to develop a technique for the stable production of Italian ryegrass(IRG) seeds in reclamation sites. Harvesting 35 days after heading in Autumn resulted in the highest production, an average of 2,232kg/ha. The production yield decreased due to seed loss as harvesting was delayed to 45 and 55 days post-heading. For the harvested 35 days post-heading, under growing rice sowing resulted in 80% seed yield of after rice sowing's; spring sowing resulted in 40%. After rice sowing using the domestic IRG seeds of 30kg/ha produced the highest seed yield of 2,507kg/ha. The highest straw yield has resulted when using the imported IRG seeds of 20kg/ha for after rice sowing 35 days post-heading fresh weight 36,667kg/ha, dry weight 14,500kg/ha, and TDN weight 7,895kg/ha.
        4,000원