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        검색결과 38

        3.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The poor durability issue of polymer electrolyte membrane fuel cells is a major concern in terms of their commercialization. To understand the degradation mechanism of the catalysts, an accelerated durability test (ADT) was conducted according to the protocol established by internationally accredited organizations. However, reversible and irreversible factors contributing to the loss of activity have not yet been practically segregated because of the limitations of a batch-type three-electrode system, leading to the misunderstanding of the deactivation mechanism. In this study, we investigated the effect of a fresh electrolyte on the ADT and recovery process. When the fresh electrolyte was used at every range of the cycle, the chances of incorrect detection of dissolved CO and Pt ions in the electrolyte were very low. When the same electrolyte was used throughout the test, the accumulated Pt ions were deposited on the surface of the Pt nanoparticles or carbon support, affording an increased electrochemical surface area (ECSA) of Pt. Therefore, we believe that periodic replacement by a fresh electrolyte or a continuous-flow electrolyte is essential for the precise determination of the structural and electrochemical changes in Pt/C catalysts.
        4,000원
        9.
        2020.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 고리 1호기 해체 비용 추정을 위해 외국 원자력발전소 해체 비용 데이터를 현가화한 후 원자력발전소 해체 비용 추정 회귀 분석모델을 개발하였다. 이 모델 개발에 사용된 데이터는 해체 또는 진행 중인 BWR 13기, PWR 16기의 해체 비용 데이터이다. 회귀 분석모델 도출을 위해, 해체 비용을 종속변수로 정하고, 해체 원전의 운전 특성을 반영할 수 있게 고 안된 Contamination factor와 해체 기간을 독립변수로 선정하였다. 빅데이터 분석 도구인 R language의 통계패키지를 이용 하여 회귀 분석모델을 도출하였다. 이 회귀 분석 모델을 적용하여 고리 1호기 해체 비용을 예측한 결과, 미화 663.40~928.32 백만 달러, 한화 약 7,828.12억~1조 954.18억 원이 소요될 것으로 예측되었다.
        4,600원
        10.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed what premium features significantly affect customer satisfaction and their recommendation, and what factors significantly affect product attributes. In the process, first, the loyalty program and the customer compensation program were studied to determine the impact of the customer satisfaction and recommendation. The study analyzed that quality and design of product properties had significant effects on all factors, but the brand was not significantly affected. Second, while superiority, differentiation and scarcity of luxury items are significant to customer satisfaction but superiority is only significant in relation to recommendation intention. Third, the preceding study shows that the customer compensation program has a significant impact on sales growth, but the study found that it was not for imported luxury car customers. Fourth, if the royalties program is low in awareness, it has been analyzed that the scarcity and customer satisfaction relationships among luxury goods have been adjusted. On the contrary, if there is a high level of awareness, it is analyzed that there is a control effect customer satisfaction and differentiation among luxury brands. In the conclusion, in order to satisfy customers at the import luxury car market, the differentiation of luxury goods by standard index must be strengthened and the brand must be strengthened among the attributes of the product. In addition, by raising awareness of the royalties program, the relationship between differentiation and customer satisfaction can be enhanced.
        4,600원
        12.
        2018.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The study aims to investigate the effect of post-reading question-generation activities on Korean middle school students’ English reading abilities with respect to cooperative learning. Two groups of students read the same reading materials; however, one group as an experimental group generated questions of three types, literal, inferential, and evaluative questions, while the other group as a control group answered comprehension questions. Each group was further divided into two sub-groups by cooperative and individual learning. A statistical analysis of the recall test scores reveals a positive effect of post-reading question-generation activities and cooperative learning on English reading abilities. The reading test scores by the three question types further illustrated variations across the question types: the experimental group outperformed the control group in the inferential and evaluative questions and individual learning was detected to be more effective than cooperative learning in the evaluative questions. Interactional effects were observed between post-reading activities and cooperative learning in the literal and evaluative questions. The findings suggest question-generation activities as a beneficial post-reading task, though their effectiveness can vary by question types and learning context.
        5,800원
        13.
        2013.10 구독 인증기관·개인회원 무료
        Apolipophorin III (apoLp-III) is a well-known hemolymph protein having a functional role in lipid transport and immune response of insects. We cloned full-length cDNA encoding putative apoLp-III from larvae of the coleopteran beetle, Tenebrio molitor (TmapoLp-III), by identification of clones corresponding to the partial sequence of TmapoLp-III, subsequently followed with full length sequencing by a clone-by-clone primer walking method. The complete cDNA consists of 890 nucleotides, including an ORF encoding 196 amino acid residues. Excluding a putative signal peptide of the first 20 amino acid residues, the 176-residue mature apoLp-III has a calculated molecular mass of 19,146 Da. Genomic sequence analysis with respect to its cDNA showed that TmapoLp-III was organized into four exons interrupted by three introns. Several immune-related transcription factor binding sites were discovered in the putative 5’-flanking region. BLAST and phylogenetic analysis reveals that TmapoLp-III has high sequence identity (88%) with Tribolium castaneum apoLp-III but shares little sequence homologies (<26%) with other apoLp-IIIs. Homology modeling of Tm apoLp-III shows a bundle of five amphipathic helices, including a short helix 3’. The ‘helix-short helix-helix’ motif was predicted to be implicated in lipid binding interactions, through reversible conformational changes and accommodating the hydrophobic residues to the exterior for stability. Highest level of TmapoLp-III mRNA was detected at late pupal stages, albeit it is expressed in the larval and adult stages at lower levels. The tissue specific expression of the transcripts showed significantly higher numbers in larval fat body and adult integument. In addition, TmapoLp-III mRNA was found to be highly up-regulated in late stages of L. monocytogenes or E. coli challenge. These results indicate that TmapoLp-III may play an important role in innate immune responses against bacterial pathogens in T. molitor.
        14.
        2010.10 구독 인증기관·개인회원 무료
        Ascotis selenaria, a major geometridae moth in citrus trees, annually damages the citrus leaves and fruits. The surface of young citrus fruit were usually fed by 1st larva of A. selenaria after landing or stepping onto the citrus fruits. To protect the larval damages of citrus fruits needs to predict the accurate occurrence time of the 1st larva for spraying. Because larval occurrences is dependent on the oviposition of adult female and the eggs were not found in/on citrus trees, oviposition model of A. selenaria linked with the egg development model will be helpful of protecting larval damages on citrus fruits. Adult longevity, survival and fecundity of A.selenaria was investigated at 13, 16, 20, 24, 28, 30, 32, and 35℃. The longevity decreased as the temperature increased and the female development rates (1/median longevity) were well described by a modified sigmoid model, which was used to calculate the adult physiological age. Description of the total fecundity was used by a non-linear model: The maximum fecundity of A. selenaria was estimated as 2490 eggs and peaked temperature was 19.7℃ according to the fecundity model. The cumulative age-specific oviposition rate and the age-specific survival rate was well described by 2 parameters Weibull function and a reverse logistic curve respectively. Total fecundity model, age-sepecific oviposition model, and age-specific survival model were incorporated into the oviposition model.
        15.
        2009.10 구독 인증기관·개인회원 무료
        14-3-3 proteins are known to play a pivotal role in a diverse array of cellular events such as cell survival, apoptosis, and signal transduction. Numerous 14-3-3 ζ have been cloned and characterized from a host of eukaryotic organisms including human, plants, yeast, fruit fly and silkworm. However, no study on Spodoptera exigua 14-3-3ζ in conjunction with virus infection has so far been reported in insects. It appears that expression of Se14-3-3ζ was decreased starting 24 h post-SeNPV infection as SeNPV titers seemed to increase as evidenced by intense bands of SeNPV IAP3. Interestingly, confocal microscopic analysis revealed that Se14-3-3ζ is expressed at the apical side of the NPV-uninfected gut cells, whereas it was detected mainly in the nucleus of the NPV-infected cells. Thus, despite the biological significance of Se14-3-3ζ in S. exigua in conjunction with molecular interactions between SeNPV and S. exigua is unclear now, our data suggest that Se14-3-3 ζ protein plays a role to protect S. exigua from the infection or inhibit replication of SeNPV.
        16.
        2009.10 구독 인증기관·개인회원 무료
        Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway is known to play a pivotal role in various cellular events and antiviral responses in both vertebrates and insects. In an attempt to elucidate the potential involvement of STAT on S. exigua-SeNPV interactions, the full length cDNA of SeSTAT was cloned from S. exigua. Analysis of temporal expression patterns shows that SeSTAT is expressed in all stages of life cycle such as larvae, pupae, and adult. Spatial expression analysis shows that it is highly expressed in fat body and Malpighian tubule. Interestingly, SeSTAT is induced at 24 h in response to either laminarin or LTA injection in larvae. Electrophoretic mobility shift assay (EMSA) shows that the binding of nuclear extracts from fat body cells immune-challenged with LTA to STAT5 probe was observed. In addition, SeSTAT was nuclear-translocalized in both fat body and gut cells that were challenged with LTA and laminarin, respectively. Finally, gene silencing of SeSTAT shows that SeNPV number appears to be increased. It suggests that SeSTAT may act as a negative regulator against SeNPV in midgut.
        17.
        2017.05 서비스 종료(열람 제한)
        Background : This study is designed to select the best shading materials for the 4-year old ginseng K-1 variety by examining the light volume, photosynthesis and growth characteristics of ginseng. Methods and Results : The ginseng seedling was transplanted in the 7 lines x 9 rows (63 plants)/ 1.65 ㎡. The shading materials were installed in the form of rear line with 170 ㎝ high for front pole and 100 ㎝ high for rear pole. The installation of shading materials were installed in combination of polyethylene, blue polyethylene sheet + polyethylene, polyethylene + polyethylene, polyethylene + aluminium screen 70%, polyethylene + aluminium screen 100%, aluminium shade plate to inspect the photosynthesis and ginseng's growth characteristics. The photosynthetic rate was measured on the middle of small leaf using the photosynthetic tester (L1-6400, Li-COR) a t 10 : 00 – 14 : 00 on a clear day with the light volume of 100, 200, 400, 600, 800, 1,000, 1,400, 1,800 μmol s-1m-2.For the ginseng K-1, which is 4-years old, the aerial parts growth (such as survival rate, height of plant, length of stem, diameter of steam and length of leaf) and underground part (length, diameter and weight of root) were examined in 2016. As for the PAR (photosynthetically active radiation), the aluminum shade plate showed the best performance while the polyethylene + polyethylene showed the least. As for the photosynthetic rate, the following order was shown in the decreasing order: blue polyethylene sheet + polyethylene > polyethylene > aluminium shade plate ≒ polyethylene + aluminium screen 100%, > polyethylene + polyethylene > polyethylene + aluminium screen 70%. As for the survival rate for 4-year old ginseng, the polyethylene + aluminium screen 70% showed the highest survival rate with 91.0%. As for the growth of aerial part of ginseng, the polyethylene and polyethylene + polyethylene showed the best growth. As for the underground part of ginseng, the polyethylene, blue polyethylene sheet + polyethylene, and polyethylene + polyethylene showed the best growth in the length of roots and length of main root while polyethylene and blue polyethylene sheet + polyethylene showed the best growth in the weight of roots. Conclusion : In conclusion, considering the characteristics of photosynthesis and the underground parts of ginseng, it was found that the best shading materials for K-1 4-year old ginseng is blue polyethylene sheet + polyethylene.
        18.
        2017.05 서비스 종료(열람 제한)
        Background : The study is designed to select the organic fertilizer as an additional fertilizer suitable for improving the yield of ginseng cultivar K-1 at low productive land when it is cultivated as 6-year old red ginseng. Methods and Results : This study was conducted in 2016 at a farm in Paju cultivating 6-year old ginseng root. As for the management of the cultivation land, in 2010 and 2011, Sudangrass was cultivated in order to make the organic matter content and chemical composition suitable for ginseng cultivation, and more than 15 tillage works were carried out a year. The transplantation was carried out at the planting density of 63 weeks / 1.62 ㎡ in April 2012. On May 2, the amount of 15 ℓ / 1.62 ㎡ of N 1.5 ㎏/1,000 ㎡ was supplied to the non-treatment, liquid fertilizer of fermented rice bran, liquid fertilizer of fermented soybean, seaweed and liquid yeast. N 1.5 ㎏/1,000 ㎡ was put into the soil for the fermented soybean and leaf mold. The photosynthetic rate was measured on the middle part of the small leaf by using a photosynthetic analyzer (LI-6400, Li-COR) at 10 : 00 - 14 : 00 on a clear day under PAR (photosynthetically active radiation) of 100, 200, 400, 600, 800, 1,000, 1,400, 1,800 μmol s-1m-2. The growth features of ginseng (including the length of stem, length of leaf, width of leaf, length of root and yield, etc.) as well as leaf discoloration, and root rot, etc were examined. The statistical analysis was performed 3 times in the randomized block design. For the rate of photosynthesis, the liquid fertilizer of fermented rice bran > liquid fertilizer of fermented soybean ≒ untreated ≒ fermented soybean > seaweed > liquid yeast > leaf mold was higher in that order. The survival rate ranged from 42.9% to 51.9%. As for the above-ground growth characteristics, the liquid fertilizer of fermented rice bran, liquid fertilizer of fermented soybean, seaweed and liquid yeast showed higher performance than the non-treated while the fermented soybean and leaf mold showed similar performance to the non-treatment. As for the underground growth, the liquid fertilizer of fermented rice-bran, liquid fertilizer of fermented soybean, fermented soybean, or leaf mold showed the same performance as non-treatment while the fermented soybean or leaf mold showed shorter length than non-treatment. As for the yield, the liquid fertilizer of fermented rice-bran, or liquid fertilizer of fermented soybean showed better performance than non-treatment. Conclusion : In conclusion, it was found that liquid fertilizer of fermented rice bran and liquid fertilizer of fermented soybean are the suitable organic fertilizers which can be used in ginseng cultivation for improving the quantitative yield of 6-year-old ginseng in low-producing area.
        19.
        2016.05 서비스 종료(열람 제한)
        Background : Cordyceps militaris has been an wonder drug to anti-aging efficacy and called the three main drugs with ginseng and deer antler from the past. Cordycepin, cordycepic acid (d-mannitol) and adenosine are known as functional ingredients in Cordyceps militaris. Among them, cordycepin, the representative component, has been reported as antimicrobial substance containing immune enhancement, anti-cancer and anti-inflammatory effects. Methods and Results : After Cordyceps militaris produced from different types of medium mixed with 10-fold volume of purified water, the mixture were extracted at 70±5℃ for a hour and that extracts re-extracted using ultrasonics wave for 30 minutes. Qualitative analysis of the index component was determined by using the Q-TOF (A quadrupole time-of-flight mass spectrometer), and quantitative analysis was performed by using HPLC (high-performance liquid chromatography) with Xselect HSS T3 column (2.1 X 100 mm, 2.5㎛, Waters, USA) and ultrapure water and acetonitrile as mobile phase A and B. Detection column temperature, injection volume and the flow rate were 35℃, 2 μL and 0.3 mL / minute respectively. The cordycepin content of Cordyceps militaris produced from medium mixed with vegetable and animal ingredients higher than single ingredient. Moreover, through a variety of analyzes by varying the type and content of the medium additives, the cordycepin in Cordyceps militaris produced from medium mixed with animal ingredients highest. Furthermore, the cordycepin content of a fruit body was higher than those of the a mycelium. Conclusion : These results provide a method for producing an high cordycepin content of Cordyceps militaris as functional food ingredient.
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