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        검색결과 15

        8.
        2018.05 구독 인증기관·개인회원 무료
        Roller Compacted Concrete Pavement (RCCP) is placed by roller compaction of a mixture of less cement and unit water content and more aggregates and provides excellent early strength development with the help of interlocking of aggregates and hydration. The unit cement content of RCC pavements accounts for 85% of conventional pavements, with low drying shrinkage. As low drying shrinkage leads to smaller crack widths than ordinary concrete, RCC pavements can help elevate reflecting crack resistance if applied to a base layer of a composite pavement system. In a composite pavement with an asphalt surface laid over a concrete base, pavement temperature change is important in predicting pavement performance. As movement of the lower concrete layer is determined by temperature depending on pavement depth, temperature data of the pavement structure serves as an important parameter to prevent and control reflecting crack. Among the causes of reflecting crack, horizontal behavior of the lower concrete layer and curling-caused vertical behavior of joints/cracks are considered closely related to temperature change characteristics of the lower concrete course (Baek, 2010). Previous studies at home and abroad about reflecting crack have focused on pavement behavior depending on daily and yearly in-service temperature changes of a composite pavement (Manuel, 2005). Until now, however, studies have not been conducted on initial temperature characteristics of concrete in composite pavements where asphalt surface is placed over an RCC base. Annual temperature changes of in-service concrete pavements go up to 60 ℃, and those of asphalt overlays become around the twice at 110 ℃. This study evaluated initial crack behavior of composite pavement by investigating pavement temperature by depth of an RCC base and analyzing joint movement depending on change to temperatures of continuously jointed pavements. Findings from the study suggest that in composite pavements and asphalt overlays, time of laying asphalt has an important impact on crack behavior and reflecting crack.
        12.
        2016.10 서비스 종료(열람 제한)
        Background : This study was conducted to serve as a basis for the production of high quality organic cultivation Platycodin grandiflorum Ridix roots by analyzing the content of saponins according to organic fertilizer for organic farming. Methods and Results : Platycodin grandiflorum Ridix was treated by with biodegradable film, rice husks, and sawdust, non-mulching (hand weeding). A root of Platycodon grandiflorum were analyzed saponins using HPLC harvested on October. Content of Plantycodin D3 was an average of 68.5 ㎎/100g, which appeared as 111.2 ㎎/100g highest content in the sawdust treated. Deapioplatycodin D showed the highest 48.1 ㎎/100g in the sawdust treated. The content of Platycodin D was shown to 246.2∼373.8 ㎎/100g, the highest values were observed in non-mulching, it showed the lowest value in the rice husks treated. The content of Polygalacin D showed up to 156.0 ㎎/100g in the non-mulching as the biggest difference, the lowest value were 30.1 and 32.2 ㎎/100g in sawdust and rice husks treated. Large differences between fertilizers was not showed, but the overall saponin content of Platycodin grandiflorum Ridix were low in value compared to the control than organic fertilizers. Conclusion : Large differences between mulching materials was showed, thus the overall saponin content of Platycodin grandiflorum Ridix was highest in value compared to non-mulching than sawdust treatment. Mulching Platycodin grandiflorum Ridix with sawdust was an effective method for improving saponin contents.
        13.
        2016.05 서비스 종료(열람 제한)
        Background : This study was conducted to serve as a basis for the production of high quality organic cultivation Platycodin grandiflorum Ridix roots by analyzing the content of saponins according to organic fertilizer for organic farming. Methods and Results : As basal fertilizer were treated before transplanting Platycodin grandiflorum Ridix with chemical fertilizer(Super21, 21-17-17, Namhae Chemical), mixed organic fertilizer, livestock manure, bacterial cultures and fermented oil cake in each trial of nitrogen based on 3 ㎏/10a criteria. A root of Platycodon grandiflorum were analyzed saponins using HPLC harvested on October. Content of Plantycodin D3 was an average of 40.6 ㎎ /100g, which appeared as 48.1 ㎎/100g highest content in the bacteria cultures treated. Deapioplatycodin D showed the highest 70.9 ㎎/100g in the control, the rest was investigated 28.1∼54 ㎎/100g. The content of Platycodin D was shown to 327.4∼373.8 ㎎/100g, the highest values were observed in mixed organic fertilizer, it showed the lowest value in the control. The content of Polygalacin D showed up to 336.7 ㎎/100g in the manure as the biggest difference, the lowest value were 54.5 and 74.2 ㎎/100g in bacterial cultures and control. Large differences between fertilizers was not showed, but the overall saponin content of Platycodin grandiflorum Ridix were low in value compared to the control than organic fertilizers. Conclusion : For the increasing the yield that Pharmacological effect, organic fertilizer is effective to increase the number of fine-root high which high contented with saponins.