The electrode performance of (La,Sr)MnO3 (LSM) cathodes modified by ion impregnation methods was investigated. By impregnation of nanosized electrocatalytic oxide particles into LSM structure, electrode performance of...
The electrode performance of (La,Sr)MnO3 (LSM) cathodes modified by ion impregnation methods was investigated. By impregnation of nanosized electrocatalytic oxide particles into LSM structure, electrode performance of modified LSM cathodes for the O2 reduction reaction was substantially increased. At 700°C, the electrode interface conductivity of impregnated LSM electrodes increased to 1.4 Scm−2 compared with 0.038 Scm−2 for LSM electrodes without impregnation. The electrode interface conductivity was enhanced by 36 times. Ion-impregnated LSM electrodes showed better polarization performance than LSM/Y2O3-ZrO2 and LSM/(GdCe)O2 composite electrodes reported in the literature. The results showed that LSM electrodes modified by ion impregnation are promising candidate cathode materials for intermediate-temperature solid oxide fuel cells.
The effects of cathodic current passage, (La,Sr)MnO3 (LSM) stoichiometry and the surface treatment of YSZ electrolyte on the performance of LSM/YSZ composite cathode were investigated. The cathodic current passage had...
The effects of cathodic current passage, (La,Sr)MnO3 (LSM) stoichiometry and the surface treatment of YSZ electrolyte on the performance of LSM/YSZ composite cathode were investigated. The cathodic current passage had an enhancing/activation effect on the composite cathode made of stoichiometric LSM powder (LSM-A) and YSZ powder, while it had little effect on the composite cathode made of A-site sub-stoichiometric LSM powder (LSM-B) and YSZ powder. An A-site deficiency (~0.1) is effective in inhibiting the formation of the resistive layer such as La2Zr2O7/SrZrO3 between LSM and YSZ. Also, surface treatment of YSZ electrolyte had a major effect on the cathode performance. After polishing the YSZ surface, the measured interfacial resistance of LSM-B/YSZ (50:50 wt%) decreased to 0.27 ohm cm2 from 0.50 ohm cm2 on as-sintered YSZ surface at 800°C in air. The results showed that LSM/YSZ composite cathode performance can be significantly improved by using A-site deficient LSM and thorough surface treatment of YSZ electrolyte.
Shear-induced particle migration was investigated by using a continuum diffusive-flux model for the creep flow of nickel powder viscous concentrated suspension with shear-thinning characteristics. The model, together ...
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Shear-induced particle migration was investigated by using a continuum diffusive-flux model for the creep flow of nickel powder viscous concentrated suspension with shear-thinning characteristics. The model, together with flow equations, was employed for solving the non-Newtonian flow patterns and non-uniform particle concentration distribution of mono-modal suspensions in a pressure-driven tube flow. Particle volume fraction and velocity fields for the non-homogenous shear flow field were predicted. Experimental validation was conducted by measuring the distribution of particles on samples obtained from a specially design split die for a capillary rheometer, which confirmed that particles with non-Newtonian polymeric binder under pressure-driven tube flow migrated from high to low shear rate regions, resulting in an uneven distribution of particle concentration. This investigation has direct relevance to the runner design for injection molding of highly filled polymers.
In this paper is described Olimpo: a retrieval system for UN Security Council (SC) resolutions developed using a methodology called Contextual Structured Search -CSS [3], a process model for automated representation a...
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ISBN:
(纸本)1581133685
In this paper is described Olimpo: a retrieval system for UN Security Council (SC) resolutions developed using a methodology called Contextual Structured Search -CSS [3], a process model for automated representation and extraction of the knowledge. Copyright 2001 ACM.
A unified framework for the study of stability of solutions to delay differential equations perturbed deterministically and stochastically has been presented. We review the concepts of Hopf bifurcation, centre manifol...
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A unified framework for the study of stability of solutions to delay differential equations perturbed deterministically and stochastically has been presented. We review the concepts of Hopf bifurcation, centre manifold, integral averaging method and pth-moment Lyapunov exponent, and then demonstrate their role in the stability study of a modified Duffing oscillator with time delay. Sufficient conditions ensuring D- and p-bifurcations and the changes in character of the probability density function are established for fixed and positive time delay.
Periodic solutions of delay differential equations (DDEs) splitting into stable and unstable branches are examined in an infinite-dimensional space for fixed and multiple time delays. The center manifold theorem and t...
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Periodic solutions of delay differential equations (DDEs) splitting into stable and unstable branches are examined in an infinite-dimensional space for fixed and multiple time delays. The center manifold theorem and the classical Hopf bifurcation theorem for the study of periodic solutions of ordinary differential equations (ODEs) are employed to reduce the infinite-dimensional character of the DDEs to finite-dimensional ODEs. Using integral averaging method, the vector field of the ODEs is converted and averaged into amplitude a and phase φ relations. From these relations bifurcation equations of the form ℑ (a, φ) = 0 for the solution branches are derived.
In most universities the students relinquish their patent rights when they enroll in courses. A different model is proposed where the students can own their patents and receive 98% of the net income, or they can assig...
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In most universities the students relinquish their patent rights when they enroll in courses. A different model is proposed where the students can own their patents and receive 98% of the net income, or they can assign the rights to the university and receive generous royalty sharing.
This paper presents an information systems architecture (ISA) model that comprises the integration of information systems, technology, business processes and users in public sector environment. The ISA model presented...
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ISBN:
(纸本)9729805024
This paper presents an information systems architecture (ISA) model that comprises the integration of information systems, technology, business processes and users in public sector environment. The ISA model presented considers specific aspects of the public sector as well characteristics of information systems development and use in this sector found in the literature and in the studies realised in informatic services brazilian State public enterprises. The model proposed was structured with five components: (a) Government structure (mission and organisational culture, Planning and government platform);(b) Public services (considered the " business" of public structure, with the information for citizens, for top level and government administrative technical);(c) Information systems (by including the legacy systems and executives systems information);(d) Information technology (centred in investment policies and the government computational platforms-as micro-computer and mainframe relationship) and (e) Users (centred in the necessities for public-training, adaptation and use of the SI). The model proposed was submitted to validation from informatic services Brazilian State public enterprises. The results point out the relevance of the integrated vision of their components and they permit to establish strategies for implantation of ISA model, in order to observing public sector specificity.
We present a two degrees of freedom model of machining dynamics that compactly captures the nonlinear effects of regeneration, tool wear and plowing under orthogonal machining. Extensive simulation experiments show th...
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We present a two degrees of freedom model of machining dynamics that compactly captures the nonlinear effects of regeneration, tool wear and plowing under orthogonal machining. Extensive simulation experiments show that the solutions to the governing equations of the model bear distinct similarities to signals from our earlier experiments, as reflected by both visual state portraits as well as the values of the quantifiers of a steady state dynamic system. Governing equations of the model lead to nonlinear delay differential equations, which we reduce to ordinary differential equations using Hopf bifurcation theorem and centre manifold theorem. Despite the ongoing efforts by the authors of this paper to quantify the simulations results analytically and experimentally, we strongly believe that our proposed model will be found to be amenable for studying and analyzing bifurcations that can lead to chatter in machining.
In this paper, the author shows that it is conclusive that e-commerce incorporates explanations of knowledge management theory and of the strategy area also reflecting the demands of the organizations in converting im...
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In this paper, the author shows that it is conclusive that e-commerce incorporates explanations of knowledge management theory and of the strategy area also reflecting the demands of the organizations in converting implicit knowledge (not expressed by words) in decoded knowledge, in the search for competitive advantage.
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