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41.
José Robério Rogério 《代数通讯》2013,41(10):4498-4508
Let λ(G) be the maximum number of subgroups in an irredundant covering of the finite group G. In this note we investigate the basic properties of λ(G), classify the groups for which λ(G) = 3, 4, 5 and also classify the nilpotent groups that admit only one-sized coverings. 相似文献
42.
Rogério Carrazedo Humberto Breves Coda 《Finite Elements in Analysis and Design》2010,46(11):1008-1016
This paper presents a formulation to deal with dynamic thermomechanical problems by the finite element method. The proposed methodology is based on the minimum potential energy theorem written regarding nodal positions, not displacements, to solve the mechanical problem. The thermal problem is solved by a regular finite element method. Such formulation has the advantage of being simple and accurate. As a solution strategy, it has been used as a natural split of the thermomechanical problem, usually called isothermal split or isothermal staggered algorithm. Usual internal variables and the additive decomposition of the strain tensor have been adopted to model the plastic behavior. Four examples are presented to show the applicability of the technique. The results are compared with other authors’ numerical solutions and experimental results. 相似文献
43.
M. Fernanda P. Costa Ana Maria A. C. Rocha Rogério B. Francisco Edite M. G. P. Fernandes 《Optimization》2016,65(5):1085-1104
In this article, we aim to extend the firefly algorithm (FA) to solve bound constrained mixed-integer nonlinear programming (MINLP) problems. An exact penalty continuous formulation of the MINLP problem is used. The continuous penalty problem comes out by relaxing the integrality constraints and by adding a penalty term to the objective function that aims to penalize integrality constraint violation. Two penalty terms are proposed, one is based on the hyperbolic tangent function and the other on the inverse hyperbolic sine function. We prove that both penalties can be used to define the continuous penalty problem, in the sense that it is equivalent to the MINLP problem. The solutions of the penalty problem are obtained using a variant of the metaheuristic FA for global optimization. Numerical experiments are given on a set of benchmark problems aiming to analyze the quality of the obtained solutions and the convergence speed. We show that the firefly penalty-based algorithm compares favourably with the penalty algorithm when the deterministic DIRECT or the simulated annealing solvers are invoked, in terms of convergence speed. 相似文献
44.
45.
AbstractLet λ(G) be the maximum number of subgroups in an irredundant covering of the finite group G. We prove that if G is a group with λ(G) ≤ 6, then G is supersolvable. We also describe the structure of groups G with λ(G) = 6. Moreover, we show that if G is a group with λ(G)?<?31, then G is solvable. 相似文献
46.
A new method to create a controlled notch filter for attenuation of signals based on regenerated fiber Bragg gratings is experimentally demonstrated. A fine adjustment of the notch depth is achieved by controlling the time of regeneration phenomenon in strongly saturated Bragg gratings written in standard ITU G.652 single-mode fiber. This method can used to produce tailored notch filters for several photonic applications, such as optical RF filtering, subcarrier processing or radio over fiber systems. 相似文献
47.
Carlos A.F. Marques Roberson A. Oliveira Alexandre A.P. Pohl Rogério N. Nogueira 《Optics Communications》2012,285(18):3770-3774
A fast adjustable gain equalization filter for dense wavelength division multiplexing (DWDM) system is reported. The method is based on a single long period fiber grating (LPG) which is excited by means of flexural acoustic waves. The equalization of a typical erbium doped fiber amplifier (EDFA) gain spectrum with a gain flatness of <0.3 dB over a 32 nm bandwidth is demonstrated. The filter adjustment is obtained by choosing different acoustic loads applied to the acousto-optic modulator, which presents a switching time of ~17 μs. A maximum power penalty of 0.84 dB, relatively to the back-to-back signal, was achieved. 相似文献
48.
Evaluation by empirically derived equations for the Substituent effect (α, β, γ, δ) on the 13C NMR chemical shifts for C-3, C-4. C-5 and halomethyl-substituent carbon (C-6) in isoxazoles 1-5 [where C-3 substituent (R1) = H, alkyl or phenyl, C-4 Substituent (R2) = H, alkyl, and C-5 substituent (R3) = di-or trihalomethyl, methyl and H], taking as reference the compound la, is reported. From the calculated values for the α, β, γ, δ effects for each substituent it was possible to estimate the chemical shift of each carbon of the compounds 1–5. The 13 C chemical shifts of the C-3, C-4, C-5, C-6 of these compounds, can be estimated with good precision: 94% of the calculated chemical shifts are found to be within ±1.0ppm, and 100% are found to be within ±1.5ppm. 相似文献
49.
The action modes of Lippia sidoides (Cham) essential oil as penetration enhancers on snake skin 总被引:1,自引:0,他引:1
M. B. Brito Gabriela B. Barin A. A. S. Araújo D. P. de Sousa S. C. H. Cavalcanti Ana Amélia M. Lira Rogéria S. Nunes 《Journal of Thermal Analysis and Calorimetry》2009,97(1):323-327
The aim of this work was to study the effect of Lippia sidoides essential oil (LSEO) on stratum corneum lipids and the permeation of salicylic acid. DSC and FTIR spectroscopy were applied.
LSEO 1% (v/v) significantly enhanced salicylic acid flux through snake skin. According to the DSC curves changes in the transition
temperature of the lipids were observed indicating that LSEO can interact with stratum corneum. The IR spectrum of skin treated
with LSEO showed a decrease in the peak intensity for CH2 stretchings (2920–2850 cm–1) however the peak positions did not alter suggesting the extraction of the lipids. 相似文献
50.
João Vitor de Oliveira Silva Jean Eduardo Meneguello Maíra Dante Formagio Camila Fabiano de Freitas Noboru Hioka Eduardo Jorge Pilau Rogério Marchiosi Miguel Machinski Junior Benicio Alves de Abreu Filho Paula Aline Zanetti Campanerut-Sá Jane Martha Graton Mikcha 《Photochemistry and photobiology》2023,99(3):957-966
In order, understanding the antimicrobial action of photodynamic therapy and how this technique can contribute to its application in the control of pathogens. The objective of the study was to employ a proteomic approach to investigate the protein profile of Staphylococcus aureus after antimicrobial photodynamic therapy mediated by rose bengal (RB-aPDT). S. aureus was treated with RB (10 nmoL L−1) and illuminated with green LED (0.17 J cm−2) for cell viability evaluation. Afterward, proteomic analysis was employed for protein identification and bioinformatic tools to classify the differentially expressed proteins. The reduction in S. aureus after photoinactivation was ~2.5 log CFU mL−1. A total of 12 proteins (four up-regulated and eight down-regulated) correspond exclusively to alteration by RB-aPDT. Functionally, these proteins are distributed in protein binding, structural constituent of ribosome, proton transmembrane transporter activity and ATPase activity. The effects of photodamage include alterations of levels of several proteins resulting in an activated stress response, altered membrane potential and effects on energy metabolism. These 12 proteins required the presence of both light and RB suggesting a unique response to photodynamic effects. The information about this technique contributes valuable insights into bacterial mechanisms and the mode of action of photodynamic therapy. 相似文献