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        검색결과 11

        1.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of the promising supercapacitors for next-generation energy storage is zinc-ion hybrid supercapacitors. For the anode materials of the hybrid supercapacitors, three-dimensional (3D) graphene frameworks are promising electrode materials for electrochemical capacitors due to their intrinsic interconnectivity, excellent electrical conductivity, and high specific surface area. However, the traditional route by which 3D graphene frameworks are synthesized is energy- and time-intensive and difficult to apply on a large scale due to environmental risks. Here, we describe a simple, economical, and scalable method of fabricating grafoil (GF) directly into a graphite–graphene architecture. Both synthesizing of a porous structure and functionalization with interconnected graphene sheets can be simultaneously achieved using electrochemically modified graphite. The resultant graphite electrode provides a high capacitance of 140 mF/cm2 at 1 mA/cm2, 3.5 times higher than that of pristine grafoil, keeping 60.1% of its capacitance when the current density increases from 1 to 10 mA/cm2. Thus, the method to produce 3D graphene-based electrodes introduced in the current study is promising for the applications of energy storage devices.
        4,000원
        4.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-quality and solution processable graphene sheets are produced by a simple electrochemical exfoliation method and employed as a high-power anode for lithium-ion batteries (LIBs). The electrochemically exfoliated graphene (EEG) composed of a few layers of graphene sheets, have low oxygen content and high C/O ratio (~ 14.9). The LIBs with EEG anode exhibit ultrafast lithium storage and excellent cycling stability, but low initial efficiency. The excellent rate capability and cycling stability are attributed to the favorable structural and chemical properties of the EEG, but the large irreversibility needs to be overcome for practical applications.
        4,000원
        5.
        2017.05 서비스 종료(열람 제한)
        Background : Ginseng is becoming depleted of virgin cultivation area due to the problem of replant failure. Ginseng farmers have become more burdensome in operating expense because they are more likely to go out to other cities in search of virgin cultivation area. In addition, the quality and yield of ginseng cultivated in one place for many years depend on the rapidly changing climate every year. The purpose of this study was to develop a method for continuous production of ginseng in a facility by solving the problems of replant failure and investigating basic soil composition and growth characteristics of ginseng for 2 - 6 years. Methods and Results : This study was carried out in a 90 ㎝ wide, 50cm deep and 22 m long bed made of sandwich panels in a 90% shaded facility for ginseng cultivation. In the lower part of the bed, a 100 ㎜ pipe for drainage and steam sterilization was installed, and the pearlite was filled at a height of 100 ㎜ as a drainage material. The soil for ginseng cultivation was put into the bed. Soil composition was tested in five combinations including virgin soil, yokto, peat moss, pearlite, and vermiculite with different composition ratios including control. The native seedlings were transplanted and grown from 2 years to 6 years. In the growth characteristics and yield of ginseng, the best treatments were virgin soil 55%, yokto 10%, Peatmoss 25%, Perlite 5% and 5% vermiculite. Also, the bulk density was reduced by 30% compared to the control. Soil pH and EC tended to increase slightly during all treatments. In the ginsenoside analysis, there were no unusual results for the soil composition and they were almost similar. Conclusion : As a method to continuously grow ginseng in the facility, we tried to grow ginseng by filling the soil in the bed. Soil composition should be within the range of chemistry and physics suitable for cultivation of ginseng, and it is necessary to analyze the economy and reduce the operating expense. In the future, researches on soil disinfection and nutrient management methods for continuous use should be continued.
        6.
        2016.10 서비스 종료(열람 제한)
        Background : This experiment was carried out to improve the labor-intensive task to construct of the traditional ginseng shading system in Korea. In this experiment the selected shading materials was new 6 kinds that HDPE - knitted- monofilament and taped PE Net, with taking into account of the amount of light and the amount of leakage to screen the UV stabilized 0.3% - 0.6%. Compared with the traditional shading material, the black-shading material (wt. 200g/㎡) and the yellow shading material (wt. 300g/㎡) was suitable for the ginseng growing environments in Korea. Methods and Results : The installation of shading system was the 45 degree slope -2 meter height from the ground with the selected shading materials for the wide structure ginseng cultivation. Temperature and light intensity was measured with a week interval from the surface to a height of 30cm. The two kinds of the 1st selected materials and the traditional black + blue two layer shading materials, aluminum screen, Canada Gintec shading material, total 5 kinds of materials were installed in wide structure. The growing environmental analysis was measured using data logs (watchdog 1600series). Conclusion : In the first selection of shading materials for Ginseng wide structure, the levels of light intensity were higher in order of blue-shading> Aluminum- shading> black-shading order. The temperatures of the under wide structures were lower in order of the black-shading< aluminum-shading screen< blue-shading order, especially the temperature of the black shading material was lower than the outside temperature. For the second selection of shading material of the ginseng wide structure, the black and yellow shading material were superior to the other materials, in the amount of light shading material and growing conditions and the degree of leakage etc. The temperatures of mid-May in wide structures of ginseng cultivation were higher in order of aluminum-screen> Canada shading materials (Gintec Co.) 2 layer material> Yellow shading> black shading order, and also the amounts of light intensity also was shown to be with the same manner
        7.
        2016.10 서비스 종료(열람 제한)
        Background : The production of healthy ginseng seedling is a critical part of growing 5-6-year-old fresh ginseng. Recently, for the problem of replant failure, it becomes more and more difficult to find first planted field for ginseng seedling cultivation. In this situation, This study was conducted to examine the possibility of seedling production practices of ginseng by utilizing the multi-beds cultivation system as a way to produce ginseng seedling stably. Methods and Results : This experiment was conducted by installing a 3-layed cultivation beds using 50㎜ sandwich panels. As the 1st and 2nd beds get insufficient amount of light, fluorescent lights were installed in 2 rows to further lighten up. And the 3rd bed used natural light. The bed soil used was formulated by mixing saprolite, yakto and peat moss. The control was cultivated under natural light on 1-layed bed with commercial bed soil for ginseng seedling. The commercial bed soil had pH 7.24, higher than the standard of permission, 6.5; and its calcium and sodium contents were 10.7, and 0.85 cmol+/㎏, respectively, higher than the standard. The available phosphate concentration was 34.0㎎/㎏, lower than the appropriate level of 100 ㎎/㎏. The mixing bed soil also had pH 7.69, higher than the standard but its nitrate and phosphate were within the appropriate range. The intra-facility light quantities of the 1st and 2nd beds were constant at around 100 μmol during days. But the light quantity of the 3rd bed was 51.4 μmol in average daily value. The roots of the 1st-3rd beds were found to weigh 0.58 – 0.73 g while those of the control group, about 0.47g to show heavier root weight of the multi-beds cultivation ginseng than that of the control. As for the yield, the control showed 145 ㎏/10a whereas the 1st-3rd beds showed higher levels between 183 – 228 ㎏/10a. Conclusion : In the multi-beds cultivation of ginseng seedling, fluorescent lamps seem to have provided sufficient light as an artificial light source. The soil for ginseng seedling production is different from ginseng cultivation field soil, additional study will be also necessary to set up the physiochemical range of bed soil for ginseng seedling.
        8.
        2016.05 서비스 종료(열람 제한)
        Background : Ginseng farmers prefer first planted field because of replant failure. But the accumulation of nutrients is higher in the first planted field due to using large amounts of chemical fertilizers and manure. The higher phosphate concentration in preparation field decreased emergence ratio and occurred leaf chlorosis in ginseng. The purpose of this study was to develop a technology for reducing phosphate concentration in preparation field of ginseng. Methods and Results : This study was performed in farm's fild located Yeongju in 2015. Treatment of plots consisted of sudangrass, maize, deep plowing + sudangrass and microbes(Rhodobacter sphaeroides, Bacillus subtilis, streptomyces griseus) + sudangrass. sudangrass and maize were sown in early May to 5kg / 10a. Microbes diluted 500 times were treated to drench the soil before sowing crops(400L/10a). The main survey was yield of crop, soil chemical properties, reduction ratio of phosphate and changes in available phosphate. Reduction ratio of phosphate in the plot of maize and Rhodobacter sphaeroides were 27.9% and 24.3%, respectively, which were higher 2∼5% than the control plot. Fresh weight yield was the highest with 11.1ton / 10a in the plot of maize and ratio of dry matter was the highest with 27% in the plot of maize. Conclusion : The phosphate removal ability of maize was better than sudangrass in phosphate accumulation soil. Subsoil reversed using excavators used by some farmers could not mitigate of phosphate and salts concentration in preparation field. The soil that phosphate concentration is more than 1,000mg/kg is required a long-term management.
        9.
        2016.05 서비스 종료(열람 제한)
        Background : The Ginseng has been one of the crops that represents Korea, and the main export items in the 1960s, Now it occupies the first exports of agricultural products. The Eco-friendly cultivation of Ginseng was difficult for various reasons. But the cultivation in Green House can be suppressed disease occurrence, when utilizing an environmentally friendly materials has the advantage that can dramatically increase the income by possible organic production. For other crops, it made up a lot of studies on water management, But the studies on water management of ginseng is somewhat lacking. Therefore, this study was conducted to establish appropriate soil- moisture-management-systems within the house of ginseng cultivation. Methods and Results : The type of house is a double steel structure. The first layer was PE film, the second layer was the blue shading net and 75% black shading net. The Soil texture was silt loam and the Soil Series was YEONGOK Series. Install the house on the adjacent paddy soil and upland soil, and planting on April 30, 2011 which was cultivated by the straw mulching. The irrigation start point was the 40, 30, 20kpa, and the end point was treated with 15, 10kpa. Soil moisture measurements were determined by tension meter(Jet Fill) depth 20cm in soil. Growth and Yield Survey was conducted in accordance with the Rural Development Administration (RDA) standard research. Statistical analysis of the results were analyzed using the Microsoft's Excel 2003. Conclusion : In a survey due to differences in soil traits and Irrigation point, from 2 years to 4years of root weight and yield of Ginseng were heavier in the upland, especially 30kpa irrigation point treatment was heaviest than the other treatments. From 5year to 6 Years of ginseng has showed heavier in paddy soil, the most treatment was 30kpa- 15kpa irrigation point. This trend was the same in upland soil. Soil moisture management in the case of silt loam, the humid-state-control was more advantageous than dry-state control in upland and paddy soil.