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        검색결과 28

        1.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 선박용 디젤 엔진에서 발생되는 크랭크케이스 수트(soot)의 재활용 가능성을 검토하기 위하여, 수트를 배기관에서 발생하는 수트와 크랭크케이스에서 발생한 수트로 분류하고, 열처리에 따른 수트의 구조적 특성을 분석하였다. 열처리는 아르곤 가스 분위기에서 2,000℃와 2,700℃로 열처리를 수행하였고, 샘플의 구조적 특성 분석을 위해 라만분광법(Raman spectroscopy)과 고분해능 전자현 미경(HRTEM)을 활용하였다. 또한, 취득한 HRTEM 이미지를 정량적으로 분석하기 위해 디지털 이미지 처리(Digital Image Processing) 기법을 활용하였다. 라만 분석 결과, 배기 수트와 2,700℃로 열처리한 수트에서 상대적으로 높은 G/D ratio가 나타났다. HRTEM 이미지에서는 두 수트 모두 유사한 형태의 흑연화된 나노 구조를 확인할 수 있었으나, 수트의 종류와 열처리 온도차에 따른 흑연화 정도의 차이를 정량 적으로 도출할 수 없는 한계가 있었다. 이에 Digital Image Processing을 통해 HRTEM 이미지의 fringe의 길이와 곡률을 정량적으로 분석하였으며, 라만 분석과 일치하는 결과를 도출할 수 있었다. 이는 배기 수트가 크랭크케이스 수트에 비해 더 흑연화 된 구조를 가지는 것을 의미하며, 더 높은 온도에서 열처리 할 경우 흑연의 구조로 더 잘 발달함을 의미한다. 본 연구의 결과로 크랭크케이스 수트 역시 배기 수트 와 마찬가지로 흑연계 재료로 재활용이 가능함을 확인하였다.
        4,000원
        2.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 IMO의 향후 예상 규제 물질 중 하나인 수트를 선박용 엔진을 대상으로는 최초로 배기 수트와 엔진 수트로 구분 하여 구조적 특성의 비교 분석을 시도하였다. 그리고 최근 발표되고 있는 배기 수트 재활용 연구의 연장선상에서 엔진 수트의 재활용 가 능성 여부를 확인하기 위하여 2,000℃로 열처리를 시행하였고, 열처리 전·후의 수트를 고분해능 전자현미경과 라만분광법을 통해 분석하 였다. 전자 현미경을 통한 분석 결과, 배기 수트와 엔진 수트는 유사한 형태의 나노 구조를 가지고 있으나, 배기 수트는 구형의 1차 입자 가 체인형 결합구조를 가지고 있었고, 엔진 수트는 배기 수트에 비해 무정형한 구조가 확인되었다. 라만분광법 분석 결과, 배기 수트와 엔 진 수트 모두 D peak(1,350 cm-1)와 G peak(1,580 ~ 1,600 cm-1)가 확인되었다. 다만, G/D ratio는 엔진 수트에 비해 배기 수트가 상대적으로 높게 나타나며, 이는 배기 수트가 더 흑연화 된 구조를 나타냄을 의미한다. 열처리 후의 분석 결과, 엔진 수트도 배기 수트와 유사하게 흑연화 가 문제없이 진행됨을 확인하였고, 이를 통해 선박용 디젤엔진에서 발생하는 배기 수트와 엔진 수트 모두 흑연재료로 재활용이 가능함을 확인하였다.
        4,000원
        6.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to explore possibilities of cultivating horticultural crops in the air-dome greenhouse in comparison to the common iron-frame greenhouse as the standard. The levels of carbon dioxide and atmospheric pressure measured inside the air-dome greenhouse turned out to be higher than those measured inside the iron-frame greenhouse. Contrastingly, light intensity was relatively weaker inside the air-dome greenhouse due to the air-inflated double layers. Plants of melon and cherry tomato were cultivated from May 2 to August 12, 2016, respectively in the two greenhouses. For melon plants, growth in the air-dome greenhouse effectively increased fruit weight as well as trunk circumference compared to iron-frame greenhouse. Moreover, soluble sugar content of melon fruit was significantly higher when cultivated in the air-dome greenhouse. For cherry tomato plants, fruit yield of cherry tomato was significantly increased inside the air-dome greenhouse. Furthermore, it has been found that the air-dome greenhouse was considerably effective in shortening the growing period of melon and cherry tomato plants in comparison to the iron-frame greenhouse.
        4,000원
        8.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Plant growth and development strongly influenced by light quantity and its spectral composition. Young tomato plants were cultivated in growth cabinets under artificial light provided by red and blue light emitting diodes(LEDs) during 12 hours, then plants were exposed to monochromatic ultraviolet, blue, green and red lights as an end-of-day(EOD) treatment during 4 hours to study their effect on plant growth parameters. EOD lighting from various LEDs increased total fresh and dry weights as well as assimilation area compared to those in control. Blue light increased stem height, internode length and stem diameter. Monochromatic UV-A light reduced stem elongation, highly increased stomatal conductance. Compactness and health index of young tomato plants were increased in UV-A and red light treatments.
        4,000원
        9.
        2014.07 구독 인증기관·개인회원 무료
        Customer loyalty programs have been widely adopted for customer relationship management all over the world. The proliferation of loyalty programs causes program competition which weakens the effectiveness of loyalty programs at the end of customers. In general, existed research suggests that the increasing competition among rival programs in a single industry may cancel out the expected roles of loyalty programs (Mägi, 2003). For example, program competition is a substantial threat to customer lifetime value and share of wallet (Leenheer, van Heerde, Bijmolt, & Smidts, 2007; Meyer-Waarden, 2007). Liu and Yang (2009) find the sales impact of a single loyalty program diminishes as program competition increases. Their study also shows this negative effect is weaker in a highly expandable product category. Although previous studies have examined the suppressive effect of program competition on financial outcomes of loyalty programs, little research has explored its role on attitudinal customer loyalty formation process. This study aims to explore the differential roles of program competition on two formation processes of customer loyalty. It intends to contribute to the loyalty programs literature in two aspects. First, this study examines two routines of customer loyalty formation in the context of loyalty programs. That is, a company can leverage program offerings to build customer loyalty through increased customer satisfaction or strengthened customer identification with the company. Second, this study examines the moderating roles of program competition on those two loyalty-generating routines. Specifically, it finds customer identification is more important for building customer loyalty at the presence of program loyalty.
        10.
        2014.06 구독 인증기관 무료, 개인회원 유료
        Renal dysplasia is a developmental disorder of the renal parenchyma involving anomalous differentiation. It is characterized by persistent metanephric ducts surrounded by primitive mesenchyme, fetal or immature glomeruli, fetal or immature tubules, interstitial fibrosis, and dysontogenic metaplasia involving tissues such as cartilage. Renal dysplasia has been rarely reported in rats. Here, we observed a small left kidney in a rat used in a short-term repeat toxicity study. The rat showed no clinical signs throughout the study. All parameters, including those reflecting kidney functions, were normal upon hematological examination and urinalysis. Grossly, the kidney was small (5 × 8 mm) and its surface appeared normal. Histological examination revealed that the cortex and medulla were poorly demarcated and contained immature/atrophic glomeruli, immature renal tubules, and mesenchymal cells. The cortex contained immature glomeruli, atrophic glomeruli with cystic dilatation of Bowman’s capsular space, and some atypical tubules. Primitive metanephric tubules in the medulla were larger in diameter than normal collecting ducts, lined by a tall columnar epithelium with pale cytoplasm and basal nucleus, and surrounded by loose mesenchymal cells. Occasional tubules contained pale eosinophilic homogenous material in the lumen. Thus, this was diagnosed as a case of renal dysplasia on the basis of histologic features and is the first reported case of renal dysplasia in Sprague Dawley rats.
        3,000원
        11.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The recent development in genetic assisted selection (combining traditional- and genome assisted selection method) and reproduction technologies will allow multiplying elite cow in Hanwoo small farm. This review describes the new context and corresponding needs for genome assisted selection schemes and how reproductive technologies can be incorporated to get more genetic gain for cow genetic improvement in Hanwoo. New improved massive phenotypes and pedigree information are being generated from commercial farm sector and these are allowing to do genetic evaluation using BLUP to get elite cows in Korea. Moreover cattle genome information can now be incorporated into breeding program. In this context, this review will discuss about combining the reproductive techniques (Multiple Ovulation Embryo Transfer; MOET) and genome assisted selection method to get more genetic gain in Hanwoo breeding program. Finally, how these technologies can be used for multiplication of elite cow in small farm was discussed.
        4,000원
        12.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 등분포 하중에 종속된 폼내장 콘크리트 샌드위치 패널 (foam insulated concrete sandwich panel)의 구조거 동특성을 파악하였다. 유한요소모델이 콘크리트, 폼 그리고 철근의 비선형거동과 연결부재 (connector)의 상세 전단 저항거동을 모사하기위해 사용되었다. 개발된 모델은 미주리대학 (University of Missouri)에서 수행된 정적실험자료 를 사용하여 검증되었다. 합성 및 비합성 거동이 샌드위치패널의 구조거동에미치는 영향을 정확히 모사하기 위해 전단연결재의 저항력을 모델에 정확히 반영하는 것이 중요하다. 본 연구에서 개발된 모델은 구조물의 극한강도및 좌굴이후의 거동까지 모사하였고 미국콘크리트 학회 (ACI)의 설계예제와 비교하였다. 본연구의 결과는 정적 및 동 적하중에 종속된 폼내장 콘크리트 샌드위치 패널의 해석및 설계에 유용한 정보를 제공할것이다.
        4,000원
        13.
        2008.10 구독 인증기관·개인회원 무료
        We tested differences in female pheromone production and male response in three species of the genus Adoxophyes in Korea. Females of all three species produced mixtures of Z9-14:OAc and Z11-14:OAc as major components but in quite different ratios. The ratio of Z9-14:OAc and Z11-14:OAc in pheromone gland extracts was estimated to be 100:198 for A. honmai, 100:23 for A. orana, and 100:3880 for A. sp. Field tests showed that males of each species were preferentially attracted to the two-component blends of Z9-14:OAc and Z11-14:OAc mimicking the blends found in pheromone gland extracts of conspecific females. The effects of minor components identified in gland extracts on trap catches varied with species. Addition of 10me-12:OAc or E11-14:OAc to the binary blend of Z9-14:OAc and Z11-14:OAc significantly increased captures of A. honmai males, whereas E11-14:OAc exhibited a strongly antagonistic effect on catches of A. sp. males. Moreover, Z9-14:OH or Z11-14:OH added to the binary blends increased attraction of male A. orana but not A. honmai and A. sp. males, suggesting that these minor components, in addition to the relative ratios of the two major components, play a noteworthy role in reproductive isolation between Adoxophyes species in the southern and midwestern Korea where these species occur sympatrically.
        14.
        2016.10 서비스 종료(열람 제한)
        Background : Perilla frutescens L. is valuable as a medicinal plant as well as a natural medicine and functional food. Limonene perilla collected from various places showed 60% limonene compounds. However biological activity of these accession has not been reported before. Therefore, this study was conducted to investigate the biological activity of limonene perilla. Methods and Results : Fractional solvent extracts were obtained by using organic solvents such as n-hexane, chloroform, ethyl acetate, n-BuOH, and aqueous solvent from different parts of limonene perilla extracted initially in 70% EtOH. We investigated the effects of limonene perilla on total phenol and flavonoid contents, FRAP (Ferric Reducing Antioxidant Power), total saponin contents and tyrosinase inhibition activity. Leaves of limonene perilla produced the highest total phenolic contents (29.88 mg·CAE/g), flavonoid (8.39 mg·QE/g) and saponin contents (47.77 mg·GIE/g) than stems and roots of limonene perilla. FRAP of leaves was 823.00±3.58 μM·FeSO4·E/mg. Tyrosinase inhibition activity rate was 40.31% in 70% ethanol extracts from leaves of limonene perilla. Conclusion : This results suggest that leaf of limonene perilla fractions has significant antioxidant activity. Also, limonene perilla could be used as a functional biomaterial in developing cosmetics and functional foods.
        15.
        2012.06 KCI 등재 서비스 종료(열람 제한)
        For QTL analysis of agronomic traits based on cultivation of low and high altitude locations, BC1 F5 181 lines were developed from a cross of Tongil type Gayabyeo and japonica Chhomrong originated from Nepal. Plant materials were grown in both of low altitude area of Milyang, Korea and high altitude area of Khumaltar, Nepal. In QTLs analysis, a total of 42 QTLs were detected in days to flowering, culm length, panicle length, number of panicles/hill, panicle exertion, and spikelet ripening ratio. Although many of the QTLs were coincided between the two locations of Korea and Nepal, several QTLs were revealed as location specific in high altitude area of Khumaltar. Especially, the regions harboring marker RM489-RM14281 on chromo- some 3, RM5642-RM19049 on chromosome 5, and RM2854-RM6696 on chromosome 12 where QTLs were clustered and coincided between the two locations are considered as positive target regions for environmental independent traits. Furthermore, high rate of location specific QTLs such as panicle exertion and spikelet ripening ratio could be considered carefully for understanding the mechanism of cold tolerance based on cultivation of different altitude location.
        20.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        An unbalance of rice productions and consumptions caused serious problems in both of agricultural area and grain market of korea. In recently, various efforts for rice processing products such as rice noodles and rice wines are in progress to overcome the unstable rice market. Among them, waxy rice is predominant items in processing rice. However, varietal features of starch viscosity are not considered in the processing industries and rice breeding field. In this study, 12 waxy rices and 2 cultivars Ilmibyeo(japonica) and IR72(Indica) were studied for physicochemical and amylogram to characterize the use of waxy rices. The amylose contents of waxy rices were from 7.1 to 8.1% with soft gel consistency and relatively low alkali digestion value(1.4% KOH) compare to Ilmibyeo. In the amylogram analysis(RVU) of waxy rices, unlikely normal rices, very fast peak time(about 3.5 min.) was obtained compare to that of 6.2 min. of Ilmibyeo. And 2 to 3 groups were classified based on peak viscosity and consitency of RVU. Wangchal, Odorokimochi and Hangangchal showed relatively high peak viscosity seemed not suitable for rice cake due to the hardness speed. And most of waxy rices developed in korea were believed to be suitable for oil fried cakes(Hankwa) because of a certain grade of starch degradation speed. And Mochiminori and Midoromochi originated from japan could be a good sources in waxy rice breeding program to improve the cooking properties especially in slow down of hardness speed with very low peak viscosity, hot viscosity and cool viscosity.
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