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        검색결과 10

        1.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The carbon-containing molecule can be used as an NMR probe to explore the acidic and structural features of various catalytic materials. Thereinto, although mesityl oxide (MO) has been extensively employed to determine the acidity of solution and ionic liquid systems, could it be utilized to characterize the acidic properties of solid acid catalysts? In this work, on the basis of a series of isolated Brønsted and Lewis acid models with varied acid strengths, the adsorption configurations and corresponding 13C chemical shifts of adsorbed MO molecules have been comprehensively studied by means of a theoretical investigation approach. Among them, both the 13C chemical shift difference between β and α carbon atoms (Δδ), and the 13C chemical shift of β carbon atoms (δ13Cβ) in adsorbed MO molecules were explicitly demonstrated to be closely related to the intrinsic acid strength of Brønsted acid sites. These correlations could be utilized to quantitatively scale the Brønsted acid strength of solid acid catalysts. Besides, a moderate relationship was theoretically derived for the relevant 13C NMR parameters and intrinsic Lewis acid strength.
        4,000원
        2.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, we presented a hybrid composite of graphene quantum dots (GQDs)-modified three-dimensional graphene nanoribbons (3D GNRs) composite linked by Fe3O4 and CoO nanoparticles through reflux and ultrasonic treatment with GQDs, denoted as 3D GQDs-Fe3O4/CoO@GNRs (3D GFCG). In this hybrid, the 3D GNRs framework strengthened the electrical conductivity and the synergistic effects between GQDs and 3D GFCG enhanced the oxygen reduction reaction (ORR) activity of the nanocomposite. The results imply that decorating GQDs with other electro-catalysts is an effective strategy to synergistically improve their ORR activity.
        4,000원
        3.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to identify the differences between Korean and Chinese and males and females in terms of female image preferences. The survey was conducted for 1 month targeting male and female Korean and Chinese subjects. Among the 350 completed questionnaires, 309 were used for analysis. For the analysis, 11 female images were chosen based on theoretical study, then a t-test and a paired t-test were carried out using SPSS 19.0. The results of this study are as follows: First, differences in female image preferences were observed to depend on nationality and gender. Koreans prefer urban images while Chinese prefer cute, intelligent, and sexy images. Second, males prefer innocent or sexy images, while females prefer sophisticated images. Third, Korean males prefer innocent, active, sophisticated, gentle, cute, sexy, urban, natural, intelligent, spectacular, and neutral images in order. Chinese males prefer gentle, innocent, sexy, active, sophisticated, intelligent, cute, natural, urban, spectacular, and neutral images in order. Fourth, Korean females prefer sophisticated, gentle, urban, natural, intelligent, innocent, active, sexy, cute, spectacular, and neutral images in order. Chines females prefer sophisticated, intelligent, cute, gentle, innocent, active, natural, sexy, urban, spectacular, and neutral images in order. Using these results, it will be possible to design marketing strategies for global consumers.
        4,900원
        4.
        2018.07 구독 인증기관·개인회원 무료
        Today, customers experience a multitude of online and offline touchpoints along their shopping journeys. A customer touchpoint is defined as a direct or indirect encounter with a firm along shopping process (Baxendale et al., 2015). Touchpoints can be oneway or two-way interactions between customers and firms (Verhoef, Kannan, & Inman, 2015). Instant experiences are initiated by firms, others or by customers themselves. These experiences influence customer’s overall experience with brands, and furthermore, have impact on customers' subsequent attitude and behaviour. Another important question for managers is to decide whether to aim for creating frequent encounters: focus on volume, or creating instant experiences with stronger positive-emotional response: focus on valence. Prior research investigated different touchpoints separately and mostly focused on the effect of the volume of touchpoint encounters on attitudes and behaviour. Taking a holistic perspective, we investigate the effects of volume and valence of customers’ previous experiences of firm, others and customer initiated touchpoints on satisfaction and current purchases. We employed a real-time tracking method where respondents reported their touchpoint experiences via a mobile phones, each time they encountered the focal brand in a 4- week period in supermarket, healthcare and banking categories. We employ a twostep dynamic Heckman Probit model to investigate the impact of volume and valence of touchpoints on customer behaviour, and a multivariate regression to investigate the touchpoint effects on brand satisfaction along customer journeys. Our results reveal that brand satisfaction is mostly explained by the effect of touchpoint valence and not touchpoint volume. Our behaviour model reveals that the volume, rather than valence, of previous customer initiated purchases and transactions impacts the frequency of current purchases.
        5.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research was conducted to investigate the effects of feeding high and low forage diets with different forage sources on rumen fermentation characteristics and blood parameters of Holstein cows during the dry period. Eight Holstein cows were completely randomized assigned to two groups and repeated measurement was utilized in the analysis. Cows in two treatments were fed with diets with high (F:C = 70:30, 70F; forage source: mixed-sowing whole crop barley and Italian ryegrass silage, BIRG) and low (F:C = 55:45, 55F; forage source: tall fescue hay, TF) forage level. Rumen fluid pH was higher in 70F group. Levels of acetic acid, propionic acid, and butyric acid showed a similar pattern: from the lowest value at 07:30 h to the highest at 10:30 h and then decreased in both groups. The ratio of acetic acid to propionic acid was significantly higher (p < 0.05) in 55F group at 09:30 and 10:30 h. Rumen fluid NH3-N concentrations were significantly higher (p < 0.05) in 70F group at 09:30 and 10:30 h. Blood urea nitrogen was significantly higher (p < 0.05) in 70F group. It was concluded that BIRG based diet with a high forage level had no adverse effects on rumen fermentation, some blood chemical parameters, and immune system in dry Holstein cows and could be used as a forage source instead of imported TF.
        4,000원
        6.
        2014.07 구독 인증기관 무료, 개인회원 유료
        The wine industry is an emerging market in Malaysia. This study focuses on identifying the factors influencing wine consumption among working professionals. 309 out of 350 questionnaires distributed in the Klang Valley, Malaysia were useful. The findings show that three factors (self-expression, health and emotion) are statistically significant in determining wine consumption behaviour among working professionals. Although marketers like to believe that their efforts drive the demand of particular wines, it was concluded that labelling and branding of wine was not correlated with wine consumption behaviour. Practical implications for wine producers and marketers are discussed.
        4,200원
        7.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The precipitation polymerization of acrylonitrile (AN) was carried out in a mixture solution of dimethyl sulfoxide (DMSO) and water at 50~65℃ using α,α'-azobisisobutyronitrile (AIBN) as an initiator. The increased molecular weight polyacrylonitrile (PAN) was prepared with increasing the H2O/DMSO ratio from 10/90 to 80/20. The viscosity average molecular weight of H2O/DMSO solvent was 4.4 times larger than that of H2O/DMF solvent, and precipitation polymerization was accelerlated due to the far decreased chain transfer effect of DMSO. Based on the experimental results, the increased PAN molecular weight was regarded as the summation of two mechanisms: i) particle-particle aggregation and ii) particle-radical attachment. The theoretical equation derived from the mechanisms was well coincided with the experimental results showing the linear relationship between the viscosity average molecular weight and the H2O/DMSO ratio.
        4,000원
        8.
        1996.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,800원
        9.
        2019.02 서비스 종료(열람 제한)
        With the increasingly mature development of China's Internet technology, China's e-commerce has developed, which has given a huge boost to China's economic growth. In recent years, mobile payment has become a bright spot in China's economy, promoting the further development of e-commerce. On the one hand, various e-commerce sales and service platforms in China have greatly developed and with Alibaba as the representative, the annual turnover of e-commerce sales platform has increased year by year. On the other hand, with the implementation of the "one belt and one way" policy, cross-border electricity providers have promoted China's trade with the world and become China's new economic growth point. This paper analyzes the current situation of e-commerce in China and puts forward Suggestions for the further development of e-commerce in China.
        10.
        2003.02 KCI 등재 서비스 종료(열람 제한)
        The Yellow River delta is an important region where coastal and newly formed wetlands distribute in north China. Based on satellite remote sensing images and GIS techniques, this paper tends to delineate the dynamic changes of newly formed wetland in the Yellow River mouth from 1986.5 to 1996.10. Our results show that the newly formed wetland increased by 24.9 km2 per year. Before 1990.1 and it decreased by 2.40 km2 per year after that. The northern and southwestern parts of the Yellow River mouth are main positions of decrease and the southern and the estuary parts are main positions of increase. The advancing rate of river mouth extending into the Bo Sea is decreasing obviously. The reason for that is the decreasing of water and sediments in the Yellow River, which caused by the increasing use of water and soil conservation on upper reach.