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A facile and fast microwave-assisted ionic liquid method has been developed to prepare PtRu nanoparticles onto multi-walled carbon nanotubes (MWCNTs). This novel method has some advantages, such as the high electrocatalytic activity of the catalysts for the methanol oxidation, simple preparation procedures, and recycle of the ionic liquids. Transmission electron micrograph shows that PtRu nanoparticles with diameter of 2-5 nm are uniformly deposited along the length of the MWCNTs (PtRu/MWCNTs). The structure and nature of the resulting PtRu/MWCNT catalysts are also characterized by X-ray diffraction. Electrochemical measurements show that the electrocatalytic oxidation of methanol shows very high catalytic efficiency compared with commercial E-TEK Pt/C (20 wt%Pt) catalysts, which is crucial for anode electrocatalysis in direct methanol fuel cells. © 2010 Elsevier B.V. Source

Xu Y.,Qufu Normal University
Computers and Industrial Engineering

In this paper, a new approach is proposed to solve group decision making (GDM) problems where the preference information on alternatives provided by decision makers (DMs) is represented in four formats of incomplete preference relations, i.e.; incomplete multiplicative preference relations, incomplete fuzzy preference relations, incomplete additive linguistic preference relations, incomplete multiplicative linguistic preference relations. In order to make the collective opinion close each decision maker's opinion as near as possible, an optimization model is constructed to integrate the four different formats of incomplete preference relations and to compute the collective ranking values of the alternatives. The ranking of alternatives or selection of the most desirable alternative(s) is directly obtained from the derived collective ranking values. A numerical example is also used to illustrate the applicability of the proposed approach. © 2011 Elsevier Ltd. All rights reserved. Source

Yu X.,Nanjing Southeast University | Xie X.-J.,Qufu Normal University
IEEE Transactions on Automatic Control

This paper develops a unifying framework for output feedback regulation of stochastic nonlinear systems with more general stochastic inverse dynamics. The contributions of this work are characterized by the following novel features: 1) Motivated by the concept of integral input-to-state stability (iISS) in deterministic systems and stochastic input-to-state stability (SISS) using Lyapunov function in stochastic systems, a concept of stochastic integral input-to-state stability (SiISS) using Lyapunov function is first introduced, two important properties of SiISS are obtained: (i) SiISS is strictly weaker than SISS using Lyapunov function; (ii) SiISS is stronger than the minimum-phase property. However, only under the minimum-phase assumption, there is no dynamic output feedback control law for global stabilization in probability. 2) Almost sure boundedness, a reasonable and stronger concept than boundedness in probability, is introduced. The purpose of introducing the concept is to prove the boundedness and convergence of some signals in the closed-loop control system. 3) Some important mathematical tools which play an essential role in the boundedness and convergence analysis of the closed-loop system are established. 4) A unifying framework is proposed to design a dynamic output feedback control law, which drives the states to the origin almost surely while maintaining all the closed-loop signals bounded almost surely. © 2010 IEEE. Source

Ma C.-Q.,Qufu Normal University | Zhang J.-F.,CAS Academy of Mathematics and Systems Science
IEEE Transactions on Automatic Control

Consensusability of multi-agent systems (MASs) is a fundamental problem in the MAS research area, since when starting to design a consensus protocol, one should know whether or not there exists such a protocol that has the ability to make the MAS involved consensus. This technical note is aimed at studying the joint impact of the agent dynamic structure and the communication topology on consensusability. For the MASs with fixed topology and agents described by linear time-invariant systems, a necessary condition of consensusability with respect to a set of admissible consensus protocols is given, which is shown, under some mild conditions, to be necessary and sufficient. © 2010 IEEE. Source

With anodized titanium in fluoride-containing perchloric acid solution as an example in the present Article, the physical origin of the faradaic pseudocapacitance C 0 frequently observed in electrochemical impedance spectroscopy (EIS) spectra at low frequencies was interpreted for the first time by the incorporation/insertion of some electrolyte anions (i.e., F-ions in this work) into the oxide film under the electric field during film growth. It was shown that the emergence of the faradaic pseudocapacitive behavior not only indicates a significant incorporation of anions into the oxide films but also reflects the arrival of them at the metal/oxide interface. The anion incorporation/transfer process was depicted with a modified point-defect model and simulated by a blocking, restricted finite-length diffusion impedance model (which has been widely used for studying the ion-insertion electrodes). The fast inward migration of the incorporated electrolyte species, along with the accumulation of them at the metal/film interface (due to the blocking effect of this interface), is responsible for the low-frequency capacitance behavior revealed by a vertical capacitive line in EIS spectra at low frequencies for anodically growing oxide films on valve metals. Many related published results for anodized valve metals (such as Ti, Bi, Ta, Al, etc.) are in good accordance with the model predictions. This work also suggests that the electrochemical method for the preparation of F --doped TiO 2 thin film materials should be an easy, low-cost, and even more effective one to be used. © 2010 American Chemical Society. Source

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