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        검색결과 26

        1.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, numerical analysis is conducted to investigate the flow characteristics of a turning type flood gate fishway with various design factors. The shapes of the fishway are circular and rectangular type. Baffles are installed to reduce the velocity in the fishway, and the gap and rotational arrangement of the baffles are set as design factors. To reduce the maximum velocity, a cavity-shaped break region is installed to examine the flow characteristics according to the presence of the break region. As a result, in the condition where the shape of the fishway is rectangular, the outlet average flow velocity is larger than that in the circular condition. The highest flow velocity occurs when the baffle is rotated in 90-degree arrangement. As the baffle gap increases, the average velocity increases. The cavity-shaped break region creates a recirculation zone in the fishway, and as a result, shows a decrease in the maximum velocity of up to 5.8%.
        4,000원
        2.
        2017.10 구독 인증기관·개인회원 무료
        Little consideration has been given to the insect epizootiology in pest management. High production cost of fungalinsecticides might be a technical barrier. Application of the fungal insecticides to unfavorable conditions might result inlower performance in pest management. Herein this work, we suggest ecological biocontrol considering long-term colonizationin nature rather than quick pest control. Fungal biopesticides should be frequently combined with chemical pesticides infields, particualrly spatial combination strategy rather than temporal combination. Additionally other important technicalaspects need to be strongly considered, such as economic downstream process, effective control and environmentally safe,so finally proposing e-biopesticide. Lastly R&D system needs to be clearly and efficiently organized for high performance.Week-based summary and reporting system, weekly report and project file are main system in our laboratory which hasour lab work more effectively and efficiently, consequently resulting in tech-transfer to an industry and re-investment.
        3.
        2016.04 구독 인증기관·개인회원 무료
        Western flower thrips, (Pergande) (Thysanoptera: Thripidae) have been recognized as serious pests worldwide. Commercially available chemical pesticides challenges against the resistance of the pest and safety to consumers. Herein we investigated the usability of soil-treatment of entomopathogenic Beauveria bassiana (Bb) ERL isolates in tomatoes. Bb-egfp was highly virulent to western flower thrips in laboratory conditions and colonized in soil, which provided a chance for western flower thrips larvae to contact the colonized fungal mass. In a glasshouse trial, Bb ERL836 and Bb ERL1578 granule (GR) were applied to soil surface and mixed well, and five females were infested to each pot of tomato 3 days after the application. The two treatments significantly reduced thrips population in tomatoes 20 and 40 days post applications, comparable to the control efficacy of clothianidin granule (GR) formulation. In the following field trial, the two ERL fungal treatments showed 69.2% and 61.5% of control efficacy, which were similar to that of clothianidin GR (76.9%). This work suggests that applied B. bassiana colonized in soil well and thrips larvae easily contacted the fungal mass, which possibly enabled the control strategy to be alternative way to the chemical control.
        4.
        2015.10 구독 인증기관·개인회원 무료
        The present issue of insect resistance and environmental toxicity of pesticides is triggering deep discussion about the pest management tactics, in which pest monitoring and control activity are mainly involved. Novel control agents, hopefully overcoming the present issues and problems, should be researched and commercially applied to the farm fields. With the monitoring-based research, additionally we have to focus on the control-based, particularly control agent-based research and application. Entomo- pathogenic fungi can used as one of the possible novel control agents once considerations are given to the control of soil- or water-dwelling pests. In our research group, the entomopathogenic fungal library has been constructed using the mealworm-based isolation system, which showed a variety of opportunities of their use in pest control. Important key production technologies including granular formulation have been developed to increase their industrialization. Some entomopathogenic fungal isolates showed high biological performance in the control of rice weevils, western flower thrips and Japanese bettles in field stands. To elucidate the fungal mode of action, a fungal transformation system using AtMT and gene identification tools were established. Recently a more deep study about the relationship between insect and entomopathogenic fungi is be investigated using RNA seq. We suggest that to make the entomopathogenic fungal products be applied to agricultural farm field, R&D of down-stream process should be seriously considered as the key step.
        5.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Methanol as a carbon source in chemical vapor deposition (CVD) graphene has an advantage over methane and hydrogen in that we can avoid optimizing an etching reagent condition. Since methanol itself can easily decompose into hydrocarbon and water (an etching reagent) at high temperatures [1], the pressure and the temperature of methanol are the only parameters we have to handle. In this study, synthetic conditions for highly crystalline and large area graphene have been optimized by adjusting pressure and temperature; the effect of each parameter was analyzed systematically by Raman, scanning electron microscope, transmission electron microscope, atomic force microscope, four-point-probe measurement, and UV-Vis. Defect density of graphene, represented by D/G ratio in Raman, decreased with increasing temperature and decreasing pressure; it negatively affected electrical conductivity. From our process and various analyses, methanol CVD growth for graphene has been found to be a safe, cheap, easy, and simple method to produce high quality, large area, and continuous graphene films.
        4,000원
        6.
        2008.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present an optical-infrared photometric study of galaxies in six nearby clusters of galaxies at z=0.041∼0.098 (A1436, A1773, A1809, A2048, A2142, and A2152). Using BV I photometry obtained at the Bohyunsan Optical Astronomical Observatory and JHKS photometry extracted from the 2-Micron All-Sky Survey catalog, we investigate the colors of galaxies in the clusters. Using the (B − V ) versus (I −KS) color-color diagrams in comparison with the simple stellar population model, we estimate the ages and metallicities of bright early-type member galaxies. Early-type galaxies in each cluster show the color-magnitude relation. Ages and metallicities of early-type members show little dependence on their velocity dispersions. Mean ages of early-types in the clusters range from 3 Gyr to 20 Gyr, showing a large dispersion, and mean metallicities range from Z = 0.03 to 0.05 above the solar value, showing a negligible dispersion.
        4,200원
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