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1.
A class of long-range predictive adaptive fuzzy relational controllers is presented. The plant behavior is described over an extended time horizon by a fuzzy relational model which is identified based on input-output closed-loop observations of the plant variables. In this class of adaptive controllers the control law attempts to minimize a quadratic cost over an extended control horizon. When used with linear models, this approach has revealed a significant potential for overcoming the limitations of one-step ahead schemes, such as the stabilization of non-minimum phase plants. Here, a uniform framework is adopted for implementing both the fuzzy model and the fuzzy controller, namely distributed fuzzy relational structures gaining from their massive parallel processing features and from the learning capabilities typical of the connectivist approaches. Issues such as maintenance during the adaptation process of the meaning of linguistic terms used at both fuzzy systems interfaces are addressed, namely by introducing a new design methodology for on-line fuzzy systems interface adaptation. The examples presented reinforce the claim of the usefulness of this new approach. 相似文献
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Fátima Nunes Serralha José Madeira Lopes Francisco Lemos Duarte Prazeres Maria Aires-Barros Joo Rocha Joaquim Cabral Fernando Ramôa Ribeiro 《Reaction Kinetics and Catalysis Letters》2000,69(2):217-222
Novel [CrIII(amp)(bipy)(Cl)] (1) (H2amp = N-(hydroxyphenyl)salicyldimine; bipy = 2,2-bipyridyl) and [CrIII(app)(bipy)(Cl)]+ (2) (H2app = N-(hydroxyphenyl)pyridine-2-carboxaldimine; bipy = 2,2-bipyridyl) complexes have been synthesized and characterized by physico-chemical methods. Complexes 1 and 2 have been employed as catalysts in the oxidation of both saturated and unsaturated hydrocarbons using tert-butylhydroperoxide (t-BuOOH). The significance of the results with respect to oxo-functionalization of C-H bonds both in unsaturated and saturated hydrocarbons is noted. 相似文献
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Maria Merces Marques C. Costa F. Lemos F. Ram?a Ribeiro A. R. Dias 《Reaction Kinetics and Catalysis Letters》1997,62(1):9-15
In this paper we present a kinetic approach to the analysis of steady-state homogeneous Ziegler-Natta polymerization activity
data. The influence of the number of monomeric species that are coordinated to the active site on the apparent rate law is
discussed and the equations are fitted to the experimental results. 相似文献
9.
Preconcentration Systems Using Polyurethane Foam/Me-BDBD for Determination of Copper in Food Samples
Valfredo Azevedo Lemos Daniel Rodrigues Vieira Cleber Galvão Novaes Marcelo Eça Rocha Moacy Selis Santos Regina Terumi Yamaki 《Mikrochimica acta》2006,153(3-4):193-201
A new reagent, 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid (Me-BDBD), was synthesised and
used in on-line and off-line systems for copper preconcentration by solid-phase extraction. Spectrophotometry and Flame Atomic
Absorption Spectrometry (FAAS) were the detection techniques. Polyurethane foam loaded with Me-BDBD packed in a minicolumn
was used as sorbent in both systems. The spectral characteristics of Me-BDBD were investigated. The optimum pH values for
maximum sorption of the metal are between 7.0 and 8.5. Copper was desorbed with 0.05 and 0.50 mol L−1 hydrochloric acid solutions, for on-line and off-line systems, respectively. The effects of several foreign substances on
the adsorption of copper are reported. The enrichment factors obtained were 7 (on-line) and 26 (off-line) for the systems.
The proposed procedures allowed the determination of copper with detection limits of 3.4 and 1.4 μg L−1 (0.85 and 0.35 μg per gram of sample) for on-line and off-line systems, respectively. The precision of the procedures was
also calculated: 3.2 (on-line) and 1.9% (off-line). The validation of the procedures was carried out by analysis of certified
reference material. The copper contents in corn and rice flour and black tea samples were determined by applying the proposed
procedures. 相似文献
10.
Valfredo Azevedo Lemos Douglas Gonalves da Silva Anaildes Lago de Carvalho Dbora de Andrade Santana Geisiane dos Santos Novaes Adenilde Souza dos Passos 《Microchemical Journal》2006,84(1-2):14-21
A new chelating sorbent has been developed using Amberlite XAD-2 resin anchored with pyrocatechol through –N=C– group. This sorbent, characterised by elemental analysis and infrared (IR) spectra, was used as packing for the minicolumn in an on-line system preconcentration system for cadmium, cobalt, copper and nickel determination. Metal ions were sorbed in the minicolumn, from which it could be eluted directly to the nebulizer–burner system of the flame atomic absorption spectrometer (FAAS). Elution of all metals from minicolumn can be made with 0.50 mol L− 1 HCl or HNO3. The enrichment factors obtained were 16 (Cd), 24 (Co), 15 (Cu) and 19 (Ni), for 60 s preconcentration time, and 39 (Cd), 69 (Co), 36 (Cu) and 41 (Ni), if used 180 s preconcentration time. Under the optimum conditions, the proposed procedure allowed the determination of cadmium, cobalt, copper and nickel with detection limits of 0.31, 0.32, 0.39 and 1.64 μg L− 1, respectively, when used preconcentration periods of 180 s. The accuracy of the developed procedure was sufficient and evaluated by the analysis of the certified reference materials NIST 1515 apple leaves and NIST 1570a spinach leaves. The method was applied to the analysis of food samples (spinach, black tea and rice flour). 相似文献