• Title/Summary/Keyword: mediator

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Improved Performance of a Microbial Fuel Cell with Polypyrrole/Carbon Black Composite Coated Carbon Paper Anodes

  • Yuan, Yong;Kim, Sung-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.29 no.7
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    • pp.1344-1348
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    • 2008
  • A microbial fuel cell (MFC) has been regarded as noble clean energy technology that can directly convert biomass to electricity. However, its low power density is a main limitation to be used as a new energy source. To overcome this limitation, we focused on the anode improvement in a mediator-type MFC using P. vulgaris as a biocatalyst. Fuel cell performance increased when the anode was coated with carbon black or polypyrrole. The best performance was observed when polypyrrole/carbon black (Ppy/CB) composite material was coated on a carbon paper electrode. Our obtained value of 452 mW $m^{-2}$ is the highest value among the reported ones for the similar system. The effects of amount of Ppy/CB, mediator concentration, and amount of P. vulgaris have also been examined.

A Study on Hybrid Database Integration Model for Product Data Management (PDM을 위한 하이브리드 데이터베이스 통합 모델에 관한 연구)

  • Lee, Kang-Chan;Lee, Sang;Yoo, Jung-Yeon;Lee, Kyu-Chul
    • The Journal of Society for e-Business Studies
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    • v.3 no.1
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    • pp.23-41
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    • 1998
  • In a centralized database system, all system components reside at a single platform. In recent years there has been a rapid trend toward the integration of information systems over multiple sites that are interconnected via a communication network, and users' needs are changed to integration of multiple information sites. Multi database System is one of solutions for integrating distributed heterogeneous databases. However the problems in multi database system are restriction in distributed environment support, limitation in integrating heterogeneous media type data, static integration, and data-only of integration. In order to solve these problems, we propose a hybrid database integration model, HyDIM. HyDIM is used for the integrating legacy multimedia data, adopting CORBA, MDS, and mediator. We demonstrate a prototype system far PDM application domain.

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Reaction Conditions for Laccase Catalyzed Degradation of Bisphenol A

  • Kim, Young-Jin
    • Journal of Environmental Health Sciences
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    • v.30 no.2
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    • pp.79-83
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    • 2004
  • The oxidative degradation of BPA with laccase from Trametes versiclor was conducted in a closed, temperature controlled system containing acetate buffer for pH control. The effects of medium pH, buffer concentration, temperature and mediator on degradation of BPA were investigated. The inactivation of the enzyme by temperature and reaction product was also studied. The optimal pH for BPA degradation showed about 5. Buffer concentration did not affect BPA degradation. On the other hand, the enzyme stability was higher at low concentration buffer(25 mM). Temperature rise increased the degradation rate of BPA up to 45$^{\circ}C$. The valuable mediator of laccase for BPA was ABTS. Elevated temperature and reaction product irreversibly inactivated the enzyme.

Assessing the Mediating Effects of the Factors on the Relationships between Customers' Past Behavior and Negative Word-of-Mouth Intention in Western Restaurant (서양 음식점에 대한 고객들의 과거 행동과 부정적인 구전 행동 의도의 관계에 미치는 매개 효과 평가)

  • Kang, Jong-Heon;Pyo, Gil-Taek
    • Journal of the East Asian Society of Dietary Life
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    • v.16 no.5
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    • pp.615-622
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    • 2006
  • The purpose of this study was to examine the mediating role of attitude, subjective norm, and perceived behavioral control on the relationships between past behavior and customers' intention to engage in negative word-of-mouth communication of dissatisfaction responses. Results of the study demonstrated that the inclusion of past behavior improved the predictability of the negative word-of-mouth communication of dissatisfaction response intentions. Furthermore, the mediating analyses indicated that the influence of past behavior was mediated by the mediator. In the contests of negative word-of-mouth communication, the effect of past behavior on intention was partially mediated by attitude, subjective norm and perceived behavioral control.

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Well-being as a Mediator between Self-discrepancy and Dropout Intention of Junior College Student (자기불일치와 전문대학생의 중도탈락의도와의 관계에서 안녕감의 매개효과)

  • HYUNG, Jung-Eun
    • Journal of Fisheries and Marine Sciences Education
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    • v.28 no.2
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    • pp.550-563
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    • 2016
  • This study examined well-being as a mediator between self-discrepancy and dropout intention of junior college Student. 270 students in Busan answered the questionnaire about self-discrepancy, well-being, dropout intention. Structural equation modeling indicated that there were the complete mediating effect of well-being in the relationship between self-discrepancy and dropout intention. It indicated discrepancy between individuals' representation of their actual self(their actual self-state) and their representation of individual's hopes and aspirations(their ideal self-guide) affects junior college students' dropout intention, and well-being mediate process of self-discrepancy leading to dropout intention. This conclusion provide the significant implications that help preparing psychosocial intervention strategy for junior college students to decrease dropout intention and intervention strategy to enhance their well-being.

Electrochemical Behaviors of ABTS2- on the Thiol-modified Gold Electrodes

  • Kim, Hyug-Han
    • Journal of the Korean Electrochemical Society
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    • v.9 no.3
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    • pp.113-117
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    • 2006
  • The electrochemical properties of the redox mediator, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate) ($ABTS^{2-}$) were studied using cyclic voltammetry. The measured potentials (${E^o}'$ vs SCE) of the two redox couples of ABTS are 0.45 V for $ABTS^{2-}/ABTS^{\cdot-}$ and 0.87 V for $ABTS^{\cdot-}/ABTS^0$. The rate constant for heterogeneous electron transfer and the diffusion coefficients for $ABTS^{2-}$ are $5x10^{-3}cm\;s^{-1}$ and $3.1x10^{-6}cm^2\;s^{-1}$, respectively. Our interest in $ABTS^{2-}$ stems from the fact that this molecule functions as a substrate to the copper oxidase, laccase, by providing the reducing equivalents necessary for the biocatalyzed reduction of dioxygen to water. Consequently, when laccase is tethered to an electrode surface or dissolved in solution, $ABTS^{2-}$ can be used to quantify enzyme activity electrochemically.

Customization, Network Effect, Service Quality and Customer Loyalty : An Investigation of Music Streaming Services (고객화, 네트워크 효과, 서비스 품질 및 고객 충성도 : 음원 스트리밍 서비스를 중심으로)

  • Eum, Sangwon;Rhim, Hosun;Han, Youngmi
    • Journal of Information Technology Services
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    • v.18 no.4
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    • pp.115-134
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    • 2019
  • The global music industry has been growing steadily every year. In particular, the proportion of music streaming services in the overall market are expanding. It shows same pattern in domestic market. Also, several companies are providing music streaming services competitively. It is clear that there is growing interest in effective operations of music streaming services. In this study, we examine the impact of customization and network effect on service quality and customer loyalty. We collect survey data and analyze relationships between latent variables using structural equations modeling. We find that customization and network effect of music streaming services positively affect service quality. However, the effect of customization on customer loyalty is not significant and there is a negative effect of network effect on customer loyalty. Finally, we find that service quality works as a mediator between customization and customer loyalty, and service quality also works as a mediator between network effect and customer loyalty.

Design XML Meidator for Content-based Query Processing (내용기반 질의 처리하기 위한 XML Mediator)

  • Yoo, Cwang-Yul;Kim, Heung-Shik
    • Annual Conference of KIPS
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    • 2001.10a
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    • pp.47-50
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    • 2001
  • 최근 인터넷의 발전으로 방대한 정보가 존재함에 따라 이들 정보들을 통합 관리할 필요성이 증대하고, 웹 검색 시스템의 서비스가 텍스트 뿐만 아니라 이미지나 사운드 데이터와 같은 멀티미디어 정보까지 보편화되어 검색의 결과로 서비스를 제공하고 있다. 기존의 검색결과를 보면 멀티미디어 데이터에 대한 검색결과는 부가적 정보로서 서비스를 제공하기 때문에 검색 결과에 대해서도 정확한 결과에 대한 서비스를 제공하지 못하고 있다. 본 논문에서는 XML기반에서 멀티미디어 데이터 소스에 대한 메타데이터를 DTD로 설계하여 내용기반 질의를 효과적으로 분산처리 할 수 있도록 Mediator를 설계한다.

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The Impact of Facebook Access Motivation on Facebook Addiction among High School Students: The Mediator Role of Online Self-Disclosure

  • Lee, Eunhee
    • International Journal of Advanced Culture Technology
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    • v.7 no.2
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    • pp.103-112
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    • 2019
  • Online self-disclosure was hypothesized as a mediating variable, explaining the relationship between Facebook access motivation (relationship expansion, curiosity about others' life, maintenance of social connection, social pressure from others, habitual use, impression management, searching for information, and content sharing) and Facebook addiction. Data came from 407 high school students in the Busan, and Gyeongnam provinces. Structural analysis was used to specify the relations among measured construct. Facebook access motivation of curiosity about others' life, Facebook access motivation of maintenance of social connection, Facebook access motivation of social pressure from others, Facebook access motivation of habitual use, and Facebook access motivation of impression management were significant predictors of Facebook addiction. Online self-disclosure mediates between Facebook access motivation of curiosity about others' life, Facebook access motivation of social pressure from others, Facebook access motivation of searching for information & Facebook access motivation of content sharing and Facebook addiction. Viewing online self-disclosure as a mediator has important implications for social media addiction counseling practice.

Mediating Effects of the Factors on the Relationships between Customers' Past Behavior and Intention to Voice at Western Restaurant in Suncheon City (순천시지역 서양음식점에 대한 고객들의 과거행동과 불평행동의도의 관계를 매개하는 요인들의 효과 평가)

  • Pyo, Gil-Taek;Kang, Jong-Heon
    • Journal of the Korean Society of Food Culture
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    • v.21 no.5
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    • pp.500-506
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    • 2006
  • The purpose of this study was to examine the mediating role of attitude, subjective norm, and perceived behavioral control on the relationships between past behavior and customers' intention to engage in voice of dissatisfaction responses. Results of the study demonstrated that the inclusion of past behavior improved the predictability of the voice of dissatisfaction response intentions. Furthermore, the mediating analyses indicated that the influence of past behavior was mediated by mediator. In the contests of voice behavior, the effect of past behavior on intention was not mediated by attitude and perceived behavioral control. Meanwhile, subjective norm mediated the relationship between past behavior and the intention to engage in voice behavior.