• Title/Summary/Keyword: diffusion factors

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COMPARISON OF DIFFUSION COEFFICIENTS AND ACTIVATION ENERGIES FOR AG DIFFUSION IN SILICON CARBIDE

  • KIM, BONG GOO;YEO, SUNGHWAN;LEE, YOUNG WOO;CHO, MOON SUNG
    • Nuclear Engineering and Technology
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    • v.47 no.5
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    • pp.608-616
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    • 2015
  • The migration of silver (Ag) in silicon carbide (SiC) and $^{110m}Ag$ through SiC of irradiated tristructural isotropic (TRISO) fuel has been studied for the past three to four decades. However, there is no satisfactory explanation for the transport mechanism of Ag in SiC. In this work, the diffusion coefficients of Ag measured and/or estimated in previous studies were reviewed, and then pre-exponential factors and activation energies from the previous experiments were evaluated using Arrhenius equation. The activation energy is $247.4kJ{\cdot}mol^{-1}$ from Ag paste experiments between two SiC layers produced using fluidized-bed chemical vapor deposition (FBCVD), $125.3kJ{\cdot}mol^{-1}$ from integral release experiments (annealing of irradiated TRISO fuel), $121.8kJ{\cdot}mol^{-1}$ from fractional Ag release during irradiation of TRISO fuel in high flux reactor (HFR), and $274.8kJ{\cdot}mol^{-1}$ from Ag ion implantation experiments, respectively. The activation energy from ion implantation experiments is greater than that from Ag paste, fractional release and integral release, and the activation energy from Ag paste experiments is approximately two times greater than that from integral release experiments and fractional Ag release during the irradiation of TRISO fuel in HFR. The pre-exponential factors are also very different depending on the experimental methods and estimation. From a comparison of the pre-exponential factors and activation energies, it can be analogized that the diffusion mechanism of Ag using ion implantation experiment is different from other experiments, such as a Ag paste experiment, integral release experiments, and heating experiments after irradiating TRISO fuel in HFR. However, the results of this work do not support the long held assumption that Ag release from FBCVD-SiC, used for the coating layer in TRISO fuel, is dominated by grain boundary diffusion. In order to understand in detail the transport mechanism of Ag through the coating layer, FBCVD-SiC in TRISO fuel, a microstructural change caused by neutron irradiation during operation has to be fully considered.

A Theoretical Framework for the Study of the Affecting Factors on the Internet Technology Adoption at U.S Banks (미국은행의 인터넷 기술 도입요인 분석을 위한 이론적인 틀에 관한 연구)

  • 장용택;유상진
    • Journal of Korea Society of Industrial Information Systems
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    • v.5 no.3
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    • pp.94-110
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    • 2000
  • While most of the previous information technology adoption and diffusion researches focus the critical factors not on the organizational perspective but on the individual perspective based on the various reasons such as informational characteristics. This paper will try to analysis the adoption and diffusion factors of the Internet related technologies based on the organizational perspective. Nowadays, in especially, the evolving and fast diffusing Internet related technologies and the flourishing e-commerce applications pressure retail banks that prepare the new types of online payment systems to maintain their existing and new customer relationship and compete with their potential competitors in the coming market environments. In addition, while most previous researches only focus on the adoption of new information technologies, this paper not only analysis the adoption of innovational technology but also analysis the diffusion process in an organization, which encourage practitioners and researchers to reveal more detail and practical analysis of the innovational technology adoption and diffusion process in ann organizational setting. Based on the previous researches, there are several factor-category will be selected for this research: 1) organizational factor, 2) within banking industry factor, 3) non-banking industry factor, 4) customer acceptance factor, 5) government factor, and 6) the functionality of e-commerce systems factor. Finally, in this study, we assumed that the more sophisticated e-commerce adopting banks provide the more broad range of banking services in general. Thus, we develop the extended integrated technology diffusion model to provide empirical evidences to distinguish between adopters and non-adopters and explain the diffusion levels of e-commerce using the level of services provided via Internet to the customer in retail bank industry.

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A Study on the Loyalty to Web Based Cyber Trading Systems (웹기반 사이버트레이딩시스템의 충성도에 관한 연구)

  • 이원호;김은홍;권순범
    • Journal of the Korean Operations Research and Management Science Society
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    • v.29 no.2
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    • pp.97-116
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    • 2004
  • Recently, e portion of on-line stock brokerage has been rapidly increased to be more than 50%, on the basis of contracted money. The usage of wCTS(Web Based Cyber Trading Systems) has now got into the steady state over the initial diffusion stage, which means wCTS has got more-than-half customer base in on-line service. Therefore, brokerage service providers have their competitive strategic focus on customer retention through the enhancement of customer loyalty. This study provides framework and survey results on explanation of wCTS user's loyalty, what and how factors affect wCTS user's loyalty. We adopt the results of early studies on information technology acceptance and diffusion such as TAM(Technology Acceptance Model) and IDT(Innovation Diffusion Theory). We also referred loyalty theory of marketing area and studios on CTS usage. We categorized explanation factors as three groups characteristics of users, characteristics of system, social environment. And we assumed that these three factors could affect the loyalty through two parameters : customer satisfaction and trust to the system. This study firstly shows that the ease of use and usefulness, the major factors of TAM. can also be applied to the loyalty of wCTS with resulting that the usefulness is more important than the ease of use In wCTS. Secondly, it shows that the innovative and risk-sensitive user has the lower degree of loyalty. Thirdly, it shows that the satisfaction and trust impact the loyalty simultaneously, the trust particularly impacts more strongly than the loyalty, due to the characteristics of monetary transaction in wCTS. This study provides meaningful results to the other on-line EC service fields as a first empirical research regarding the loyalty to wCTS which is a typical on-line EC service.

Factors Affecting the Diffusion of Health Center Information System (보건소 정보화시스템의 도입에 영향을 미친 요인)

  • Do, Young-Gyoung;Lee, Jung-Gyu;Park, Gi-Dong;Kim, Chang-Yup;Kim, Yong-Ik;Lee, Jin-Yong
    • Journal of Preventive Medicine and Public Health
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    • v.36 no.4
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    • pp.359-366
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    • 2003
  • Objectives : This study was conducted to review the diffusion process and factors affecting the adoption of the Health Center Information System (HIS). Methods : Data were collected from POSDATA (private company), MOHW, other Ministries and local governments. To specify the date of adoption, supplementary information was collected from 40 health centers. The following three kinds of factors were analyzed. Internal factors included type, size, and innovativeness of health centers. Community factors were composed of population sire, economic status, and level of education. Organizational environmental factors consisted of information score of the municipalities, financial support of the from central government, and the neighborhoodness of innovator health centers. Results : All health centers in the metropolitan cities of Seoul, Gwangju and Jeju adopted the HIS. The laggards were those in the metropolitan cities of Busan (18.8%), Incheon (20.0%) and Daejun (20.0%), and cities with population more than 300,000 (54.8%) and counties with health center hospitals (47.1%). Financially supported rural health centers adopted the HIS more rapidly than those not supported. The factors identified as being statistically significant (p<0.05), from a univariate analysis by Kaplan-Meier method, were: (1) internal factors of the type, size and innovativeness of health centers; (2) community factors of population size and economic status; (3) organizational environmental factors of the central government financial support and the neighborhoodness of innovator health centers. A multivariate analysis, using a Cox proportional hazard method, proved the innovativeness of health centers, central government financial support and the neighborhoodness of innovator health centers, were statistically significant (p<0.05). Conclusions : The innovativeness of health centers, financial support from central government and the neighborhoodness of innovator health centers, rather than community factors related to regional socioeconomic status, affected ffe adoption of the HIS in health centers. Further in-depth studies, modifying the MOHW's strategy to propagate the HIS to the laggard health confers, are recommended.

Spatial Diffusion Process of Private Passenger Cars in Korea (우리나라 자가용 승용차의 공간적 확산과정)

  • 李種起;韓柱成
    • Journal of the Korean Geographical Society
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    • v.36 no.1
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    • pp.52-65
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    • 2001
  • Between 1985 and 1997 the diffusion of private passenger cars first occurred in major cities such as Seoul, Busan, Daegu and the satellite cities of the capital city that enjoyed high incomes and advanced service industries and then it gradually expanded to industrial and major provincial cities while posting a downturn in the major cities. Factor contrbuting to this phenomenon most significantly was the rate of employment in the financial insurance, real estate, and business service sectors in 1985 and 1990. The most ingluential factor in 1997 was the rate of employment in agriculture, hunting, forestry, and fishery. When measured against 1991 as a yardstick, the spatiotemporal ditribution rate of private passenger cars was highly between 1985 and 1990 in Seoul's satellite cities and major regional cities, showing a large inter-regional gap in terms of diffusion rate. The period from 1991 to 1997 showed a high rate of diffusion in cities within the capital region as well as in major regional cities, but inter-regional diffusion rate became similar. Key factors responsible for regional types of the diffusion were {1}the rate of employment in the service industrier and income in the major citier, and (2)the geogtaphic distamce between counties and Seoul plus the size of population in the county regions.

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Exploratory Study of Adoption and Diffusion of Premium Digital Convergence Product: Moderating Effecting of Social Value (프리미엄 디지털 컨버전스 제품의 수용과 확산에 대한 연구: 사회적 가치의 조절효과를 중심으로)

  • Song, Young Hee;Hur, Won-Moo
    • Knowledge Management Research
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    • v.12 no.1
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    • pp.53-76
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    • 2011
  • This study aims to examine the effects of on premium convergence products buying behavior. This paper analyzed the positive attitude formation using the basic and extended TAM and also revealed how the positive premium convergence product attitude relate to relationship purchasing intention and word of mouth intention. The samples of 562 consumer indicate that the antecedents are consist of four dimension(perceived usefulness, perceived ease of use, social value) and attitude is developed into buying intention and word of mouth intention. We have reached the following conclusion about the antecedents and outcomes factors of customer attitude for the launch of premium convergence product. First, perceived usefulness, perceived delight, and social value had a positive effect on customer attitude but perceived ease of use did not. Second, we found that customer attitude had a positive effect on purchase intention and word-of mouth intention. Finally, interaction effect of perceived usefulness/perceived delight and social value had a positive effect on customer attitude. Our findings suggested that adoptian and diffusion of premium convergence product is influenced by several behavior factors. Managerially, our result emphasize that premium convergence products must satisfy not only the perceived usefulness/delight but also social value that consumers are seeking in order to be successful in the market. The theoretical and practical implications of these findings are discussed as well.

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Evaluation of Thermal Characteristics for Warm Forging Die due to Lubricants and Surface Treatments (윤활제와 표면처리에 따른 온간단조 금형의 열적특성 평가)

  • 김종호;김동진;정덕진;김병민
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.833-836
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    • 2000
  • The mechanical and thermal load. and thermal softening which is happened by the high temperature of die, in hot and warm forging, cause wear. heat checking and plastic deformation, etc. This study is for the effects of solid lubricants and surface treatments for warm forging die Because cooling effect and low friction are essential to the long lift of dies. optimal surface treatments and lubricants are very important to hot and warm forging Process. The heat that is generated by repeated forging processes. and its transfer are important factors to affect die life. The main factors, which affect die hardness and heat transfer, are surface treatments and lubricants, which are related to thermal diffusion coefficient and heat transfer coefficient, etc. For verifying these. experiments art performed for diffusion coefficient and heat transfer coefficient in various conditions - different initial billet temperatures and different loads. Carbonitriding and ionitriding are used as surface treatments. and oil- base and water-base graphite lubrirants are used. The effects of lubricant and surface treatment for warm forging die lift are explained by their thermal characteristics.

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The Study of User Resistance to Fintech Payment Service: In the Perspective of Innovation Diffusion And Status Quo Bias Theory (핀테크 지급결제 서비스 수용 저항요인 연구 : 혁신저항이론과 현상유지편향이론을 중심으로)

  • Hwang, Sin-Hae;Kim, Jeoung-Kun
    • The Journal of Information Systems
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    • v.27 no.1
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    • pp.133-151
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    • 2018
  • Purpose Global fintech industry is proliferating. Although domestic investment in fintech service is also increasing fast, user acceptance of fintech payment service seems slower than expected. Previous fintech literature mainly focuses on overall characteristics and technical aspects of fintech including security issues and explores factors affecting the service adoption. This study aims to examine crucial factors affecting user's resistance intention to fintech payment service adoption. The research model was formulated based on innovation diffusion theory and status quo bias theory and validated empirically. Design/methodology/approach The proposed research model was empirically validated with 149 responses from college students who have used fintech payment service. The component-based SEM was employed for data analysis. Findings The significant findings are as follow. First, compatibility has significant negative effect and complexity, and perceived risk has a positive effect on user resistance. Second, institutional trust does not show a significant effect on user resistance but has an indirect effect through the mediation of trust in service provider. Finally, trust in service provider shows the significant negative effect on user resistance.

Kinetic and Effectiveness Factor for Methanol Steam Reforming over CuO-ZnO-Al2O3 Catalysts (CuO-ZnO-Al2O3 촉매에서의 메탄올 수증기 개질반응에 대한 반응속도와 유효성인자)

  • Lim, Mee-Sook;Suh, Soong-Hyuck
    • Transactions of the Korean hydrogen and new energy society
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    • v.13 no.3
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    • pp.214-223
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    • 2002
  • Kinetic and effectiveness factors for methanol steam reforming using commercial copper-containing catalysts in a plug flow reactor were investigated over the temperature ranges of $180-250^{\circ}C$ at atmospheric pressure. The selectivity of $CO_2$/$H_2$ was almost 100%, and CO products were not observed under reaction conditions employed in this work. It was indicated that $CO_2$ was directly produced and CO was formed via the reverse water gas shift reaction after methanol steam reforming. The intrinsic kinetics for such reactions were well described by the Langmuir-Hinshelwood model based on the dual-site mechanism. The six parameters in this model, including the activation energy of 103kJ/mol, were estimated from diffusion-free data. The significant effect of internal diffusion was observed for temperature higher than $230^{\circ}C$ or particle sizes larger than 0.36mm. In the diflusion-limited case, this model combined with internal effectiveness factors was also found to be good agreement with experimental data.