• Title/Summary/Keyword: diffusion power

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The Combined Effects of Power Imbalance and Mutual Dependence on the Relationship between IOS Diffusion and a Firm's Performance Improvement

  • Gee-Woo Bock;Sang Cheol Park;Won Jun Lee;Cheng Zhang;Kyu Min Hwang
    • Asia pacific journal of information systems
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    • v.29 no.2
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    • pp.217-247
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    • 2019
  • This paper draws on the interdependence theory to examine the role of power and mutual dependence on the relationship between internal/external diffusion and performance improvement within a supply chain. The results from a survey of 375 respondents show that two patterns of IOS diffusion - internal diffusion and external diffusion - have different impacts on a firm's performance improvement according to differences in power and mutual dependence between two parties in the supply chain.

Minimum Density Power Divergence Estimator for Diffusion Parameter in Discretely Observed Diffusion Processes

  • Song, Jun-Mo;Lee, Sang-Yeol;Na, Ok-Young;Kim, Hyo-Jung
    • Communications for Statistical Applications and Methods
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    • v.14 no.2
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    • pp.267-280
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    • 2007
  • In this paper, we consider the robust estimation for diffusion processes when the sample is observed discretely. As a robust estimator, we consider the minimizing density power divergence estimator (MDPDE) proposed by Basu et al. (1998). It is shown that the MDPDE for diffusion process is weakly consistent. A simulation study demonstrates the robustness of the MDPDE.

Analysis of Hot Isostatic Pressing of Powder Compacts Considering Diffusion and Power-Law Creep (확산과 Power- law 크립을 고려한 압분체 열간정수압압축 공정의 해석)

  • Seo M. H.;Kim H. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.10a
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    • pp.66-69
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    • 2000
  • In order to analyze the densification behaviour of stainless steel powder compacts during hot isostatic pressing (HIP) at elevated temperatures, a power-law creep constitutive model based on the plastic deformation theory for porous materials was applied to the densification. Various densification mechanisms including interparticle boundary diffusion, grain boundary diffusion and lattice diffusion mechanisms were incorporated in the constitutive model, as well. The power-law creep model in conjunction with various diffusion models was applied to the HIP process of 316L stainless steel powder compacts under 50 and 100 MPa at 1125 $!`\acute{\dot{E}}$. The results of the calculations were verified using literature data It could be found that the contribution of the diffusional mechanisms is not significant under the current process conditions.

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Determining Diffusion Power Users in a Blog Network (블로그 연결망에서 파급력을 가진 파워 유저의 파악 기법)

  • Lim, Seung-Hwan;Kim, Sang-Wook;Park, Sun-Ju
    • Journal of KIISE:Computing Practices and Letters
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    • v.16 no.4
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    • pp.377-382
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    • 2010
  • For business purposes, it is important to identify diffusion power users, a group of users who have big influence on other users in diffusing content. In this paper, we use the independent cascade model for determining diffusion power users, and to do so, we need a method for calculating the assimilation probability between users. This paper proposes the concepts of user delivery power and a way to quantifying the value of this. User delivery power is used to compute the assimilation probability with user content power. We analyze the proposed method by comparing its performance with those of existing methods through experiments using a real blog network data.

Modelling the Densification Behaviour of Powders Considering Diffusion and Power-Law Creep Mechanisms during Hot Isostatic Pressing (열간정수압압축 시 확산기구 및 Power-law크립기구를 고려한 분말 치밀화거동의 모델링)

  • 김형섭
    • Journal of Powder Materials
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    • v.7 no.3
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    • pp.137-142
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    • 2000
  • In order to analyze the densification behaviour of stainless steel powder compacts during hot isostatic pressing (HIP) at elevated temperatures, a power-law creep constitutive model based on the plastic deformation theory for porous materials was applied to the densification. Various densification mechanisms including interparticle boundary diffusion, grain boundary diffusion and lattice diffusion mechanisms were incorporated in the constitutive model, as well. The power-law creep model in conjunction with various diffusion models was applied to the HIP process of 316L stainless steel powder compacts under 50 and 100 MPa at $1125^{\circ}C$. The results of the calculations were verified using literature data. It could be found that the contribution of the diffusional mechanisms is not significant under the current process conditions.

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Diffusion Model of Aluminium for the Formation of a Deep Junction in Silicon (실리콘에서 깊은 접합의 형성을 위한 알루미늄의 확산 모델)

  • Jung, Won-Chae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.33 no.4
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    • pp.263-270
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    • 2020
  • In this study, the physical mechanism and diffusion effects in aluminium implanted silicon was investigated. For fabricating power semiconductor devices, an aluminum implantation can be used as an emitter and a long drift region in a power diode, transistor, and thyristor. Thermal treatment with O2 gas exhibited to a remarkably deeper profile than inert gas with N2 in the depth of junction structure. The redistribution of aluminum implanted through via thermal annealing exhibited oxidation-enhanced diffusion in comparison with inert gas atmosphere. To investigate doping distribution for implantation and diffusion experiments, spreading resistance and secondary ion mass spectrometer tools were used for the measurements. For the deep-junction structure of these experiments, aluminum implantation and diffusion exhibited a junction depth around 20 ㎛ for the fabrication of power silicon devices.

A Study on the Solid State Diffusion Bonding of Ti-6Al-4V Alloy (Ti-6Al-4V합금의 고상 확산접합에 관한 연구)

  • 강호정;강춘식
    • Journal of Welding and Joining
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    • v.15 no.6
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    • pp.32-40
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    • 1997
  • Solid state diffusion bonding is the joining process performed by creep and diffusion, which is accelerated by heating below melting temperature and proper pressing, in vacuum or shielding gas atmosphere. By this process we can obtain sufficient joint which can't be expected from the fusion welding. For Ti-6Al-4V alloy, the optimum solid state diffusion bonding condition and mechanical properties of the joint were found, and micro void morphology at bond interface was observed by SEM. The results of tensile test showed sufficient joint, whose mechanical properties are similar to that of base metal. 850$^{\circ}$C, 3MPa is considered as the optimum bonding condition. Void morphology at interface is long and flat at the initial stage. As the percentage of bonded area increases, however, small and round voids are found. Variation of void shape can be explained as follows. As for the void shrinkage mechanism, at the initial stage, power law creep is the dominant, but diffusion mechanism is dominant when the percentage of bonded area is increased.

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Effect of Anode Gas Channel Height on Gas Diffusion and Cell Performance in a Molten Carbonate Fuel Cell (용융탄산염 연료전지 연료극 기체 유로 높이에 따른 가스 확산 및 단전지 성능 변화 연구)

  • Lee, Jung-Hyun;Kim, Do-Hyung;Kim, Beum-Ju;Kang, Seung-Won;Lim, Hee-Chun
    • Journal of Hydrogen and New Energy
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    • v.20 no.6
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    • pp.479-484
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    • 2009
  • The effect of anode gas channel height on gas diffusion and cell performance in a 100 $cm^2$ class molten carbonate single cell is investigated. Single cell separators with three different channel height are used. The effect of the gas channel height on the distribution of the reactive gas concentration is evaluated by the two-dimensional concentration diffusion equation. The overpotential caused by concentration drop with different channel height is estimated by the voltage decay related to diffusion of reactants, well known as concentration polarization, using limiting current density. The estimation could have the possibility to identify the reactant mass transfer polarization in the complicate factors of the overall electrodes.

A Study on Power System Analysis Considering Special-days Load Mobility of Electric Vehicle (특수일 이동을 고려한 전기자동차 충전부하의 전력계통 영향에 관한 연구)

  • Hwang, Sung-Wook;Kim, Jung-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.2
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    • pp.253-256
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    • 2016
  • In this paper, the power system with electric vehicles is analyzed considering the mobility and diffusion rate of electric vehicles in the smart grid environment. In the previous studies, load modeling and load composition rates have been researched and the results are applied to develop a new load model to explain the mobility of electric vehicles which could affect on the power system status such as power flow and stability. The results would be utilized to research and develop power system analysis methods considering movable charging characteristics of electric vehicles including movable discharging characteristics which could be affected by the diffusion progress of electric vehicles.