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        검색결과 130

        61.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The objective of this study is to evaluate the application of soil stabilization method for soft shoulder construction in the iRoad Project of Sri Lanka. METHODS: Firstly, the quantitative analysis of soil strength improvement due to soil stabilization was done for soil samples collected from iRoad construction sites. Two types of soils were selected from iRoad Project sites and prepared for soil stabilization testing by the Road Development Authority. Secondly, the appropriate stabilizer was selected at given soil type based on test results. Two different stabilizers, ST-1 and ST-2, produced in Korea were used for estimating soil strength improvements. Finally, the optimum stabilizer content was determined for improving shoulder performance. The uniaxial compressive strength (UCS) test was conducted to evaluate the strength of stabilized soil samples in accordance with ASTM D 1633. The use of bottom ash as a stabilizer produced from power plant in Sri Lanka was also reviewed in this task. RESULTS: It is found from the UCS testing that a 3% use of soil stabilizer can improve the strength up to 2~5 times in stabilized soft shoulder soils with respect to unstabilized soils. It is also observed from UCS testing that the ST-1 shows high strength improvement in 3% of stabilizer content but the strength improvement rate with increase of stabilizer content is relatively low compared with ST-2. The ST-2 shows a low UCS value at 3% of content but the UCS values increase significantly with increase of stabilizer content. When using the ST-2 as stabilizing agent, the 5% is recommended as minimum content based on UCS testing results. Based on the testing results for bottom ash replacement, the stabilized sample with bottom ash shows the low strength value. CONCLUSIONS: This paper is intended to check the feasibility for use the soil stabilization technique for shoulder construction in Sri Lanka. The use of soil stabilizer enables to improve the durability and strength in soft shoulder materials. When applying the bottom ash as a soil stabilizer, various testings should be conducted to satisfy the specification criteria.
        4,000원
        62.
        2018.05 구독 인증기관·개인회원 무료
        In Sri Lanka, the shoulder in asphalt pavements has been constructed using the materials transported from borrow pit in the iRoad Project due to the low quality of in-situ soils. After excavating 150~200mm thick and 500mm wide shoulder area, the borrow pit materials are placed and compacted according to specifications. The excavated in-situ soils are dumped in designated location. It is estimated that this process of shoulder construction is not economical due to high material transportation cost and can also induce the environmental issues by disposal of in-situ soils. It can also cause distresses such as surface rutting and edge drop-off in soft shoulder section due to bearing capacity failure and off-tracking of vehicle. The heavy rainfall in Sri Lanka can induce severe erosion problem when using the soft shoulder. To improve the strength and durability of pavement shoulders in the iRoad Project, the soil stabilization will be a good alternative to solve the above mentioned problems. The use of in-situ soils with addition of soil stabilizer enables to reduce the construction cost of shoulder section and mitigate the environment issues. The objective of this task is to review the application of soil stabilization method for soft shoulder construction in the iRoad Project. Firstly, the quantitative analysis of soil strength improvement due to soil stabilization was done for soil samples collected from iRoad construction sites. Two types of soils were selected from iRoad Project sites and prepared for soil stabilization testing by the Road Development Authority. Secondly, the appropriate stabilizer was selected at given soil type based on test results. Three different stabilizers, ST-1, ST-2, and ST-3, produced in Korea were used for estimating soil strength improvements. Finally, the optimum stabilizer content was determined for improving shoulder performance. The uniaxial compressive strength (UCS) test was conducted to evaluate the strength of stabilized soil samples in accordance with ASTM D 1633. The use of bottom ash as a stabilizer produced from power plant in Sri Lanka was also reviewed in this task.
        65.
        2018.04 구독 인증기관·개인회원 무료
        The insecticidal activities of 13 Lamiaceae plant oils and their components against adult German cockroaches, Blattella germanica L. (Blattodea: Blattellidae), were evaluated using fumigant and contact bioassay. Among the tested oils, basil, pennyroyal, and spearmint showed the strongest insecticidal activities against adult B. germanica. Insecticidal activity of pennyroyal was 100% against male B. germinica at 1.25 mg concentration in fumigant bioassay. Basil and spearmint revealed 100% and 100% insecticidal activity against male B. germinica at 5 mg concentration, but their activities reduced to 80% and 25% at 2.5 mg concentration, respectively. In contact toxicity bioassy, basil, pennyroyal, and spearmint oils exhibited 100%, 100%, and 98% mortality against female B. germanica at 1 mg/♀, respectively. Among the constituents identified in basil, pennyroyal and spearmint oils, insecticidal activity of pulegone was the strongest against male and female B. germanica.
        66.
        2018.04 구독 인증기관·개인회원 무료
        The developmental biology and morphological characteristics of the immature stages of Argynnis nerippe were studied in the laboratory using host plant, Viola papilionacea. Dormancy of the first instar larvae was broken when exposed in summer-like conditions (25 ± 1℃ and continuous illumination of 5000-7000 lux). Feeding began within 1-2 days after awakening. This species has six larval stadia and individuals take ca. 60 days (excluding dormancy) to mature from egg to adult. Illustrations and descriptions of the various immature stages and their behaviors are provided.
        70.
        2017.10 구독 인증기관·개인회원 무료
        We evaluated the larvicidal and nematicidal activities of 48 3-acylbarbituric acids analogues against the Asian tigermosquito, Aedes albopictus and the pine wood nematode, Bursaphelenchus xylophilus, organisms of increasing global concern.Among 48 3-acylbarbituric acids analogues, four compounds 10, 14d, 14g, and 19b showed >90% larvicidal activity againstAe. albopictus at 10μg/mL concentration, and one (compound 10) showed the strongest larvicidal activity against Ae. albopictus,with a LC50 value of 0.22μg/mL. Only compound 18 showed strong nematicidal activity against pine wood nematode.Most active compounds possessed similar physicochemical properties; thus, actives typically had ClogP values of around1.40-1.50 and rel-PSA values of 16-17%.
        71.
        2017.10 구독 인증기관·개인회원 무료
        Naringenin and its glycoside naringin (naringenin-7-O-glycoside) belong to this series of flavonoids and were well-known strong antioxidant activity. This study was conducted to flavonoid constituents and antioxidant activity of Pleurotus ostreatus and Pleurotus cornucopiae. In order to determine active ingredient contents of Pleurotus ostreatus and Pleurotus cornucopiae, we were carried out total polyphenolic content (TPC) and flavonoid content (TFC) analyses. As a result, TPC (31.05 ± 0.03 g GAE/kg extract) and TFC (13.25 ± 1.24 g NE/kg extract) of Pleurotus cornucopiae were found significantly higher as compared to Pleurotus ostreatus. The IC50 values based on the DPPH (56.50 ± 0.73 μg/ml) and ABTS (86.53 ± 3.86 μg/ml) for Pleurotus cornucopiae were generally stronger showing potential antioxidant properties compared to Pleurotus ostreatus. In addition, naringin and naringenin content were analyzed by high-performance liquid chromatography analysis. A great amount of naringin and naringenin was found in Pleurotus cornucopiae. These results indicate that the Pleurotus cornucopiae can be used as an antioxidant therapeutic agent.
        73.
        2017.07 구독 인증기관·개인회원 무료
        In the world of SNS, once ordinary users get recognized for discriminated fashion taste, they affect other users’ choice of fashion products. Fashion companies capture the importance of these influencers and tries to take advantage of their ability. However, the benefits offered to influencers such as financial compensation may provoke negative consumer reactions. The purpose of this study is to identify what aspects of SNS influencers and how they influence other fashion consumers. We suggest that influencers’ self-disclosure and authenticity of posts are important factors which elicit positive response from consumers. We also investigate the psychological mechanism of envy which can mediate the impact of self-disclosure and authenticity on consumer response. This study was conducted by an online survey of 120 Korean women in their 20s and 30s with a 2 x 2 between-group experimental design. The data was collected from 28 November to 5 December 2016. The collected data was analyzed using SPSS 23.0 for ANOVA analysis and regression analysis. The results were as follows. The main effect of authenticity was confirmed, while self-disclosure did not play a significant role, which indicates authenticity is the main factor in exercising influence on consumer response. The interaction of authenticity and self-disclosure was also observed. The participants of high in both self-disclosure and authenticity showed the strongest consumer reaction. However, the participants of high self-disclosure and low authenticity induced the weakest consumer response. For the impacts of self-disclosure and authenticity on envy, the participants exposed to the condition of both high self-disclosure and authenticity showed benign envy. On the other hand, malicious envy was aroused when both self-disclosure and authenticity were low. In relations between authenticity and consumer response, partial mediating effect of benign envy and malicious envy was confirmed. But, there was no mediating effect between self-disclosure and consumer response. This research on consumer response to influencers’ posts will provide key implications to fashion companies in building marketing strategies. In order for influencers' posts displaying their daily lives to have a positive impact on consumer response, not only self-disclosure but authenticity has to be considered. Such posts can induce benign envy and subsequently impact consumers indirectly. Influencers’ posts which narrow the gap between daily lives and products and raise the authenticity are important keys to successful marketing.
        74.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyurethane (PU) nanofibers containing graphene oxide (GO) and Ag doped functionalized reduced graphene oxide (Ag-RGO) were successfully prepared via the electrospinning technique. The uniform distribution of GO sheets along with Ag nanoparticle in the nanofibers was investigated by scanning electron microscopy and the elemental mapping technique. X-ray diffraction and thermal gravimetric analysis verified the presence of GO and Ag in the bicomposite nanofibrous mats. Antibacterial tests against Escherichia coli demonstrated that the addition of GO and Ag-RGO to the PU nanofiber greatly enhanced bactericidal efficiency. Overall, these features of the synthesized nanofibers make them a promising candidate material in the biomedical field for applications such as tissue engineering, wound healing, and drug delivery systems.
        4,000원
        76.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        경주 방사성폐기물 처분시설은 향후 80만 포장물을 처분할 계획이며 다양한 처분방식 및 관리형태를 가진 복합계가 될 것 이다. 본 논문에서는 전체부지 처분용량(80만 포장물) 처분시설의 단계별 개발에 따른 영향을 평가하기 위하여 처분시설 종 합개발계획(안)에 따른 예비안전성평가를 수행하였다. 각 시나리오에 대한 안전성평가결과 처분시설의 성능목표치를 만족 하였다. 다만, 전체처분시설의 안전성 평가결과에 중준위 방사성폐기물로 인하여 1단계 동굴 처분시설이 가장 크게 영향을 미치므로 처분시설의 안전성 향상을 위하여 처분방사능량제한 설정 등 관리방안이 필요하다. Safety Case 단계별 구축을 통 하여 중·저준위 방사성폐기물 처분시설 종합개발 과정에서 인지된 불확실성을 저감하여 안전성을 증진 시킬 수 있을 것으 로 판단된다.
        6,400원
        77.
        2016.10 구독 인증기관·개인회원 무료
        We evaluated the larvicidal activity of 12 Apiaceae plant essential oils and their components against the Asian tiger mosquito, Aedes albopictus, and the inhibition of acetylcholine esterase with their components. Of the 12 plant essential oils tested, ajowan (Trachyspermum ammi), caraway seed (Carum carvi), carrot seed (Daucus carota), celery (Apium graveolens), cumin (Cuminum cyminum), dill (Anethum graveolens), and parsley (Petroselinum sativum) resulted in >90% larval mortality when used at 0.1 mg/mL. Of the compounds identified, α-phellandrene, α-terpinene, p-cymene, (-)-limonene, (+)-limonene, γ-terpinene, cuminaldehyde, neral, (S)-+-carvone, trans-anethole, thymol, carvacrol, myristicin, apiol, and carotol resulted in >80% larval mortality when used at 0.1 mg/mL.
        78.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to investigate the effect of uterine histotroph on embryo development and the expression of cysteine-rich protein 2 (CRP2), coatomer subunit gamma-2 (G2COP), myoglobin (MYG), vascular endothelial growth factor D (VEGFD), collagen alpha 4 chain (COL4) and galactoside 3-L-fucosyltransferase 4 (FUT4) proteins in porcine embryo during pre-implantation. Uterine histotroph (UH) was collected from uterine horn on corpus albican phase, and embryos were cultured in porcine zygote medium with UH for 168 hours. Cleavage and blastocyst formation of embryo were detected at 168 hours after in vitro fertilization. And CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were observed using confocal laser microscope. In results, embryo cleavage rate was not significantly changed by UH, but blastocyst rate was significantly (P<0.05) decreased in UH-treated embryos. Moreover, CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were expressed in blastomere. CRP2 in embryo was significantly overexpressed (P<0.05), but not G2COP, MYG, VEGFD, COL4 and FUT4 proteins. In summary, UH on corpus albican phase was increased CRP2 protein in embryo, and inhibited blastocyst formation in preimplantation porcine embryos, suggesting that CRP2 may play an interrupter on embryo development in pigs.
        4,000원
        79.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cyanotoxins in aquatic ecosystems have been investigated by many researchers worldwide. Cyanotoxins can be classified according to toxicity as neurotoxins (anatoxin-a, anatoxin-a(s), saxitoxins) or hepatotoxins (microcystins, nodularin, cylindrospermopsin). Microcystins are generally present within cyanobacterial cells and are released by damage to the cell membrane. Cyanotoxins have been reported to cause adverse effects and to accumulate in aquatic organisms in lakes, rivers and oceans. Possible pathways of microcystins in Lake Suwa, Japan, have been investigated from five perspectives: production, adsorption, physiochemical decomposition, bioaccumulation and biodegradation. In this study, temporal variability in microcystins in Lake Suwa were investigated over 25 years (1991~2015). In nature, microcystins are removed by biodegradation of microorganisms and/or feeding of predators. However, during water treatment, the use of copper sulfate to remove algal cells causes extraction of a mess of microcystins. Cyanotoxins are removed by physical, chemical and biological methods, and the reduction of nutrients inflow is a basic method to prevent cyanobacterial bloom formation. However, this method is not effective for eutrophic lakes because nutrients are already present. The presence of a cyanotoxins can be a potential threat and therefore must be considered during water treatment. A complete understanding of the mechanism of cyanotoxins degradation in the ecosystem requires more intensive study, including a quantitative enumeration of cyanotoxin degrading microbes. This should be done in conjunction with an investigation of the microbial ecological mechanism of cyanobacteria degradation.
        4,500원
        80.
        2016.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Multiple color selection techniques are successful in identifying quasars from wide-field broad- band imaging survey data. Among the quasars that have been discovered so far, however, there is a redshift gap at 5 . z . 5.7 due to the limitations of filter sets in previous studies. In this work, we present a new selection technique of high redshift quasars using a sequence of medium-band filters: nine filters with central wavelengths from 625 to 1025 nm and bandwidths of 50 nm. Photometry with these medium-bands traces the spectral energy distribution (SED) of a source, similar to spectroscopy with resolution R  15. By conducting medium-band observations of high redshift quasars at 4.7  z  6.0 and brown dwarfs (the main contaminants in high redshift quasar selection) using the SED camera for QUasars in EArly uNiverse (SQUEAN) on the 2.1-m telescope at the McDonald Observatory, we show that these medium-band filters are superior to multi-color broad-band color section in separating high redshift quasars from brown dwarfs. In addition, we show that redshifts of high redshift quasars can be determined to an accuracy of z/(1 + z) = 0.002 – 0.026. The selection technique can be extended to z  7, suggesting that the medium-band observation can be powerful in identifying quasars even at the re-ionization epoch.
        4,200원
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