검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 10

        1.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        OBJECTIVES : In this study, microstructural components of crumb rubber modified asphalt (CRMA) binder were investigated using environmental scanning electron microscope (ESEM). To clearly understand the elemental composition of the CRMA binder, energy dispersive X-ray spectroscopy (EDX) was employed on the ESEM samples. METHODS: CRMA binders were produced using open blade mixers at 177℃ for 30 min. The binders were artificially aged through a series of accelerated aging processes. Sample preparation was done by making a mold shape on the glass slide. Thereafter, the morphology of the CRMA binder was observed using the ESEM coupled with the EDX. RESULTS : The images captured from the ESEM indicate that the unaged CRMA binder appears to have a single-phase continuous nonuniform structure after the addition of crumb rubber particles, whereas the artificially aged CRMA binder was observed to have two different phases. ESEM coupled with EDX shows detailed internal structure of the modified binders compared to other technologies (i.e., optical microscopy, atomic force microscopy, and conventional scanning electron microscope). CONCLUSIONS: The captured images resemble the internal structures such as the viscous properties of the unaged CRMA binder and the interaction between the rubber particles and the base binder at aged condition. ESEM is a powerful instrument and with the introduction of EDX, it provided more details of the network microstructure of the asphalt binder. ESEM coupled with EDX is recommended for use in future investigation of microstructure of asphalt binders.
        4,000원
        2.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The performance properties (indirect tensile strength, rutting resistance, and resilient modulus) of recycled aged CRM mixtures and their correlation with Superpave binder properties (viscosity, high failure temperature, G*sinδ, and stiffness) were investigated. METHODS: A series of Superpave binder tests was performed by using a rotational viscometer, DSR, and BBR to evaluate the performance properties. In addition, the CRM mixes were artificially aged through accelerated aging processes, and their properties were evaluated. The correlation between the properties of recycled aged CRM binders and the engineering properties of recycled aged CRM mixtures was experimentally determined. RESULTS : The rut depth values decreased and the ITS values increased with increasing high failure temperature. In general, the resilient modulus properties seemed to be poorly correlated with the high-temperature values, regardless of the aggregate source. CONCLUSIONS: The recycled aged CRM binders and mixtures can lead to satisfactory performance, and the properties of these binders are strongly correlated with the engineering properties of the mixtures.
        4,000원
        3.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This paper presents a description of the current issues facing road managers regarding the surface-type conversion of lowvolume roads for cost savings. METHODS: The paper reviews previous works conducted toward this end, acknowledges gaps in the current research, and lays out what information is needed for further studies. RESULTS : If the cost to maintain an unsurfaced road is less than the cost of maintaining a surfaced road, then there is potential for cost savings for the management agency. However, the problem is bigger than simply maintaining the roads that already exist. If unsurfaced roads prove to be more economical than surfaced roads, then the cost to convert from a surfaced to an unsurfaced roadway, and vice versa, when necessary, must also be examined. CONCLUSIONS : No other studies have addressed the un-surfacing of a road for cost savings, and it is therefore unknown whether substantial savings can be realistically obtained by converting from a surfaced to an unsurfaced road. To determine whether a conversion policy would be a viable option, additional data and research are needed.
        4,300원
        4.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study set out to investigate the current state of microsurfacing in Texas and compared the results with the current state of the practice nationwide. METHODS: For this study, case studies were extracted from the existing literature and compared with the data obtained both from site visits by the research team and data obtained from a survey by Texas Department of Transportation (TxDOT) personnel. The successes and failures of microsurfacing are detailed and explanations of different issues are outlined. Forensic studies from Texas are included in the descriptions of those microsurfacings that failed when configured as part of the cape seals. RESULTS : Microsurfacing has been shown to be an effective pavement preservation technique when applied to an appropriate road, at an appropriate timing, and as a remedy for certain issues. The failures experienced in Texas can mostly be attributed to cape seals and an inability to recognize structurally faulty pavement. CONCLUSIONS : When applied to an appropriate road, at an appropriate timing, and as a remedy for certain issues, microsurfacing has been shown to perform well in numerous case studies. The majority of microsurfacing failures are the result of poor project selection, usually involving the treatment being applied to structurally unsound pavement.
        4,000원
        5.
        1962.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        만부병은 포도의 착색기부터 장마가 오면 격발하는 병해로서 우리나라에 있어서 피해가 심함은 물논 방제가 어려운 것으로서 본 시험은 피대와 약제살포를 겸하는 것과 약제살포만을 하여 그 효과를 비교코저 원예시험장 과수과 포도원에서 품종 켐벨얼리를 공시하여 시험하였다. L 유대구는 무대구보다 약제간이나 무처리간에 있어서 포도만부병을 방제하는데 효과적 이였다. 2. Tuzet와 Delan은 유대구나 무대구에 있어서 다른 처리구보다 포도만부병방제에 효과적이었다
        3,000원
        6.
        2015.07 서비스 종료(열람 제한)
        Rice flour is used in many food products. However, dough made from rice lacks extensibility and elasticity, whereas that of wheat is suitable for many food products including breads. We have produced marker-free transgenic rice plants containing a wheat TaGlu-Ax1 gene encoding the HMG-GS from the Korean wheat cultivar ‘Jokyeong’ using the Agrobacteriummediated co-transformation method. The TaGlu-Bx7-own promoter was inserted into a binary vector for seed-specific expression of the TaGlu-Ax1 gene. Two expression cassettes comprised of separate DNA fragments containing only TaGlu-Ax1 and hygromycin phosphotransferase II (HPTII) resistance genes were introduced separately to the Agrobacterium tumefaciens EHA105 strain for co-infection. Each EHA105 strain harboring TaGlu-Ax1 or HPTII was infected to rice calli at a 3:1 ratio of TaGlu-Ax1 and HPTII, respectively. Then, among 210 hygromycin-resistant T0 plants, we obtained 20 transgenic lines with both TaGlu-Ax1 and HPTII genes inserted into the rice genome. We reconfirmed integration of the TaGlu-Ax1 gene into the rice genome by Southern blot analysis. Transcripts and proteins of the wheat TaGlu-Ax1 were stably expressed in the rice T1 seeds. Finally, the marker-free plants harboring only the TaGlu-Ax1 gene were successfully screened at the T1 generation.
        7.
        2011.04 KCI 등재 서비스 종료(열람 제한)
        Soybean proteins are widely used for human and animal feeds worldwide. The use of soybean protein has been expanded in the food industry due to their excellent nutritional benefits. But, antinutritional and allergenic factors are present in the raw mature soybean. P34 protein, referred as Gly m Bd 30K, has been identified as a predominant immunodominant allergen. The objective of this research is to identify the genetic mode of P34 protein for the improvement of soybean cultivar with a very low level of P34 protein. Two F2 populations were developed from the cross of "Pungsannamulkong" x PI567476 and "Gaechuck2ho" x PI567476 (very low level of P34 protein). Relative amount of P34 protein was observed by Western blot analysis. The observed data for the progeny of "Pungsannamulkong" and PI567476 were 133 seeds with normal content of P34 protein and 35 seeds with very low level of P34 protein (X2=1.157, P=0.20-0.30). For the progeny of "Gaechuck#1" and PI567476, the observed data were 177 seeds with normal content of P34 protein and 73 seeds with very low level of P34 protein (X2=2.353, P=0.10-0.20). From pooled data, observed data were 310 seeds with normal content of P34 protein and 108 seeds with very low level of P34 protein (X2=0.156, P=0.50-0.70). The segregation ratio (3:1) and the Chi-square value obtained from the two populations suggested that P34 protein in mature soybean seed is controlled by a single major gene. Single gene inheritance of P34 protein was confirmed in 32 F2 derived lines in F3 seeds, which were germinated from the low level of P34 protein obtained from the cross of "Pungsannamulkong" and PI567476. These results may provide valuable information to breed for new soybean line with low level of P34 protein and identification of molecular markers linked to P34 locus.