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Preparation and Characterization of Ordered Perovskite (CaLa) (MgMo) $_6$

  • Choy, Jin-Ho;Hong, Seung-Tae;Suh, Hyeong-Mi
    • Bulletin of the Korean Chemical Society
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    • v.9 no.6
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    • pp.345-349
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    • 1988
  • The polycrystalline powder of (CaLa) (MgMo)$O_6$ has been prepared at $1350^{\circ}C$ in $H_2/H_2O$ and $N_2$ flowing atmosphere. The powder X-ray diffraction pattern indicates that (CaLa) (MgMo)$O_6$ has a monoclinic perovskite structure with the lattice constants $a_0=b_0=7.901(1){\AA}$, $c =7.875(1){\AA}\;and\;{\gamma}=89^{\circ}$16'(1'), which can be reduced to orthorhombic unit cell, a = 5.551(1) ${\AA}$, b = 5.622(1) ${\AA}$ and c = 7.875(1) ${\AA}$. The infrared spectrum shows two strong absorption bands with their maxima at 590($ν_3$) and 380($ν_4$) cm, which are attributed to $2T_{1u}$ modes indicating the existence of highly charged molybdenum octahedron $MoO_6$ in the crystal lattice. According to the magnetic susceptibility measurement, the compound follows the Curie-Weiss law below room temperature with the effective magnetic moment 1.83(1)$_{{\mu}B}$, which is well consistent with that of spin only value (1.73 $_{\mu}_B$) for $Mo^{5+}$ with $4d^1$-electronic configuration within the limit of experimental error. From the thermogravimetric analysis, it has been confirmed that (CaLa) (MgMo)$O_6$ decomposes gradually into $CaMoO_4,\;MoO_3,\;MgO,\;La_2O_3$ and unidentified phases due to the oxidation of $Mo^{5+}$ to $Mo^{6+}$.

Focus Group Interview for childhood creativity education utilizing the media (유아 창의성 교육에 대한 현장 인식 연구 -미디어를 중심으로-)

  • Bae, Soo-Min;Youn, Jeong-Jin
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.7 no.8
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    • pp.533-540
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    • 2017
  • The purpose of this research is to explore the awareness and demand of the field of childhood creativity education using media to promote childhood creativity. First of all, we conducted a focus group interview on the actual situation, awareness, and needs of media - based creativity education in early childhood education with 6 ewperts includes 2 professors 1 director, 1 assistant director, 1 teacher. As a result of FGI, first, the actual condition of childhood creativity education using media utilizes electronic bulletin board, animation fairy tale or children's song. Second, the awareness about childhood creativity education using media is recognizing that childhood can't cur off media with thir lives, so education institution utilizes the media naturally. Lastly, the demand about childhood creativity education using media asks the plan which can use childhood creativity education using media through teacher education or training educating for pre-service teachers desirably.. So, The research suggests the need of the childhood creativity education program using media later on.

A Study on Text Mining Methods to Analyze Civil Complaints: Structured Association Analysis (민원 분석을 위한 텍스트 마이닝 기법 연구: 계층적 연관성 분석)

  • Kim, HyunJong;Lee, TaiHun;Ryu, SeungEui;Kim, NaRang
    • Journal of Korea Society of Industrial Information Systems
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    • v.23 no.3
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    • pp.13-24
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    • 2018
  • For government and public institutions, civil complaints containing direct requirements of citizens can be utilized as important data in developing policies. However, it is difficult to draw accurate requirements using text mining methods since the nature of the complaint text is unstructured. In this study, a new method is proposed that draws the exact requirements of citizens, improving the previous text mining in analyzing the data of civil complaints. The new text-mining method is based on the principle of Co-Occurrences Structure Map, and it is structured by two-step association analysis, so that it consists of the first-order related word and a second-order related word based on the core subject word. For the analysis, 3,004 cases posted on the electronic bulletin board of Busan City for the year 2016 are used. This study's academic contribution suggests a method deriving the requirements of citizens from the civil affairs data. As a practical contribution, it also enables policy development using civil service data.

Structural and Electrochemical Properties of Li2Mn0.5Fe0.5SiO4/C Cathode Nanocomposite

  • Chung, Young-Min;Yu, Seung-Ho;Song, Min-Seob;Kim, Sung-Soo;Cho, Won-Il
    • Bulletin of the Korean Chemical Society
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    • v.32 no.12
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    • pp.4205-4209
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    • 2011
  • The $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ silicate was prepared by blending of $Li_2MnSiO_4$ and $Li_2FeSiO_4$ precursors with same molar ratio. The one of the silicates of $Li_2FeSiO_4$ is known as high capacitive up to ~330 mAh/g due to 2 mole electron exchange, and the other of $Li_2FeSiO_4$ has identical structure with $Li_2MnSiO_4$ and shows stable cycle with less capacity of ~170 mAh/g. The major drawback of silicate family is low electronic conductivity (3 orders of magnitude lower than $LiFePO_4$). To overcome this disadvantage, carbon composite of the silicate compound was prepared by sucrose mixing with silicate precursors and heat-treated in reducing atmosphere. The crystal structure and physical morphology of $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ was investigated by X-ray diffraction, scanning electron microscopy, and high resolution transmission electron microscopy. The $Li_2Mn_{0.5}Fe_{0.5}SiO_4$/C nanocomposite has a maximum discharge capacity of 200 mAh/g, and 63% of its discharge capacity is retained after the tenth cycles. We have realized that more than 1 mole of electrons are exchanged in $Li_2Mn_{0.5}Fe_{0.5}SiO_4$. We have observed that $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ is unstable structure upon first delithiation with structural collapse. High temperature cell performance result shows high capacity of discharge capacity (244 mAh/g) but it had poor capacity retention (50%) due to the accelerated structural degradation and related reaction.

A Study on the Effects of Learning Organization Characteristics on Librarians' Innovative Work Behavior in Public Libraries (공공도서관의 학습조직 특성이 사서의 혁신행동에 미치는 영향 연구)

  • Hyunkyung Song
    • Journal of the Korean Society for information Management
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    • v.41 no.1
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    • pp.487-508
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    • 2024
  • This study aims to empirically analyze the effects of the learning organization characteristics in public libraries on the innovative work behavior of librarians. In this analysis, 113 librarians from 15 public libraries in the Seoul Metropolitan Area of South Korea were surveyed to investigate the learning organization characteristics of libraries and innovative work behavior. Through a multiple regression analysis of learning organization characteristics and innovative work behavior, it was found that, among the sub-factors of learning organization characteristics, creating continuous learning opportunities and creating systems to capture and share learning had a positive effect on idea realization among the sub-factors of innovative work behavior. From this, it was interpreted that public libraries should increase financial and non-financial support for librarians to learn and also that libraries should create various systems such as electronic bulletin boards and meetings in which librarians can share their learning. Moreover, the sub-factors of learning organization characteristics were found to have no effect on idea generation and idea promotion among the sub-factors of innovative work behavior, which indicated that it will be necessary to identify the organization characteristics that affect idea generation and idea promotion. This study is significant in that it identified the sub-factors of learning organization characteristics that promote the innovative work behavior of public library librarians.

Electronic Word-of-Mouth in B2C Virtual Communities: An Empirical Study from CTrip.com (B2C허의사구중적전자구비(B2C虚拟社区中的电子口碑): 관우휴정려유망적실증연구(关于携程旅游网的实证研究))

  • Li, Guoxin;Elliot, Statia;Choi, Chris
    • Journal of Global Scholars of Marketing Science
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    • v.20 no.3
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    • pp.262-268
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    • 2010
  • Virtual communities (VCs) have developed rapidly, with more and more people participating in them to exchange information and opinions. A virtual community is a group of people who may or may not meet one another face to face, and who exchange words and ideas through the mediation of computer bulletin boards and networks. A business-to-consumer virtual community (B2CVC) is a commercial group that creates a trustworthy environment intended to motivate consumers to be more willing to buy from an online store. B2CVCs create a social atmosphere through information contribution such as recommendations, reviews, and ratings of buyers and sellers. Although the importance of B2CVCs has been recognized, few studies have been conducted to examine members' word-of-mouth behavior within these communities. This study proposes a model of involvement, statistics, trust, "stickiness," and word-of-mouth in a B2CVC and explores the relationships among these elements based on empirical data. The objectives are threefold: (i) to empirically test a B2CVC model that integrates measures of beliefs, attitudes, and behaviors; (ii) to better understand the nature of these relationships, specifically through word-of-mouth as a measure of revenue generation; and (iii) to better understand the role of stickiness of B2CVC in CRM marketing. The model incorporates three key elements concerning community members: (i) their beliefs, measured in terms of their involvement assessment; (ii) their attitudes, measured in terms of their satisfaction and trust; and, (iii) their behavior, measured in terms of site stickiness and their word-of-mouth. Involvement is considered the motivation for consumers to participate in a virtual community. For B2CVC members, information searching and posting have been proposed as the main purpose for their involvement. Satisfaction has been reviewed as an important indicator of a member's overall community evaluation, and conceptualized by different levels of member interactions with their VC. The formation and expansion of a VC depends on the willingness of members to share information and services. Researchers have found that trust is a core component facilitating the anonymous interaction in VCs and e-commerce, and therefore trust-building in VCs has been a common research topic. It is clear that the success of a B2CVC depends on the stickiness of its members to enhance purchasing potential. Opinions communicated and information exchanged between members may represent a type of written word-of-mouth. Therefore, word-of-mouth is one of the primary factors driving the diffusion of B2CVCs across the Internet. Figure 1 presents the research model and hypotheses. The model was tested through the implementation of an online survey of CTrip Travel VC members. A total of 243 collected questionnaires was reduced to 204 usable questionnaires through an empirical process of data cleaning. The study's hypotheses examined the extent to which involvement, satisfaction, and trust influence B2CVC stickiness and members' word-of-mouth. Structural Equation Modeling tested the hypotheses in the analysis, and the structural model fit indices were within accepted thresholds: ${\chi}^2^$/df was 2.76, NFI was .904, IFI was .931, CFI was .930, and RMSEA was .017. Results indicated that involvement has a significant influence on satisfaction (p<0.001, ${\beta}$=0.809). The proportion of variance in satisfaction explained by members' involvement was over half (adjusted $R^2$=0.654), reflecting a strong association. The effect of involvement on trust was also statistically significant (p<0.001, ${\beta}$=0.751), with 57 percent of the variance in trust explained by involvement (adjusted $R^2$=0.563). When the construct "stickiness" was treated as a dependent variable, the proportion of variance explained by the variables of trust and satisfaction was relatively low (adjusted $R^2$=0.331). Satisfaction did have a significant influence on stickiness, with ${\beta}$=0.514. However, unexpectedly, the influence of trust was not even significant (p=0.231, t=1.197), rejecting that proposed hypothesis. The importance of stickiness in the model was more significant because of its effect on e-WOM with ${\beta}$=0.920 (p<0.001). Here, the measures of Stickiness explain over eighty of the variance in e-WOM (Adjusted $R^2$=0.846). Overall, the results of the study supported the hypothesized relationships between members' involvement in a B2CVC and their satisfaction with and trust of it. However, trust, as a traditional measure in behavioral models, has no significant influence on stickiness in the B2CVC environment. This study contributes to the growing body of literature on B2CVCs, specifically addressing gaps in the academic research by integrating measures of beliefs, attitudes, and behaviors in one model. The results provide additional insights to behavioral factors in a B2CVC environment, helping to sort out relationships between traditional measures and relatively new measures. For practitioners, the identification of factors, such as member involvement, that strongly influence B2CVC member satisfaction can help focus technological resources in key areas. Global e-marketers can develop marketing strategies directly targeting B2CVC members. In the global tourism business, they can target Chinese members of a B2CVC by providing special discounts for active community members or developing early adopter programs to encourage stickiness in the community. Future studies are called for, and more sophisticated modeling, to expand the measurement of B2CVC member behavior and to conduct experiments across industries, communities, and cultures.