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121.
A.D. Ribeiro 《Physics letters. A》2011,375(4):812-816
The semiclassical formula for the coherent-state propagator is written in terms of complex classical trajectories of an equivalent classical system. Depending on the parameters involved, more than one trajectory may contribute to the calculation. Eventually, however, two contributing trajectories coalesce, characterizing what is called phase space caustic. In this case, the usual semiclassical formula for the propagator diverges, so that a uniform approximation is required to avoid this singularity. In this Letter, we present a non-trivial numerical application illustrating this scenario, showing the accuracy of the uniform formula that we have previously derived. 相似文献
122.
Temperature Modulated DSC for the Investigation of Polymer Materials: A brief account of recent studies 总被引:1,自引:0,他引:1
Temperature modulated differential scanning calorimetry (TMDSC), the most recent development that adds periodic modulation to the conventional DSC, has recently seen a fast growth due to availability of commercial instrumentation. The use of the technique necessitates a total control of all of the experimental parameters. The paper focuses on recent applications to investigate polymers [1].This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
123.
In this work, we will prove that the modules lying in a sectional bypass of an arrow in the Auslander–Reiten quiver of an artin algebra, are either all left stable or all right stable, but not τ-periodic. Moreover, if such a bypass exists, then the Auslander–Reiten quiver has an infinite left or right stable component which contains a section with a bypass. 相似文献
124.
Since the first use of glass electrode to the detection of pH, many efforts have been made to develop new techniques and methods. In this study, the pH sensing properties of an extended gate field effect transistor (EGFET) based on the vanadium pentoxide xerogel thin film is investigated. The vanadium pentoxide was prepared by a sol–gel route. The X-ray diffractogram indicates the presence of a lamellar structure of the vanadium pentoxide xerogel films. The film was investigated as a sensor in the pH range of 2–12 and the corresponding EGFET has a sensitivity of 58.1 mV/pH. This value suggests that the material is a promising candidate for applications as disposable biosensor. 相似文献
125.
This paper focuses on the use of different memory strategies to improve multistart methods. A network design problem in which
the costs are given by discrete stepwise increasing cost functions of the capacities installed in the edges is used to illustrate
the contributions of adaptive memory and vocabulary building strategies. Heuristics based on shortest path and maximum flow
algorithms are combined with adaptive memory in order to obtain an approximate solution to the problem in the framework of
a multistart algorithm. Furthermore, a vocabulary building intensification mechanism supported by the resolution of a linear
program is also explored. Numerical experiments have shown that the proposed algorithm obtained the best known solutions for
some instances in the literature. These results show the contribution of each memory component and the effectiveness of their
combination. 相似文献
126.
The aim of this note is to clarify a minor mistake in the article: Some Applications of the Hodge-de Rham Decomposition to Ricci solitons. 相似文献
127.
Sonia de Almeida Evaneide N. Lima Marisa S. Crespi Clóvis A. Ribeiro Valdir Schalch 《Journal of Thermal Analysis and Calorimetry》2009,97(2):529-533
Urban solid residues are constituted of food remaining, grass leaves, fruit peelings, paper, cardboard, rubber, plastic, etc.
The organic fraction formed represents about 50% during the decomposition yields biogas and leachate, which are sources of
pollution. Residue samples were collected from the landfill in different and cells from several ages and the corresponding
leachate, both after treatments, were submitted to thermal analysis. Kinetic parameters were determined using Flynn–Wall–Ozawa
method. The linear relation between the two kinetic parameters (ln A and E) was verified for organic residue urban’s samples, but not for leachate’s sample. The occurred difference can be attributed
to the constituents present in leachate. 相似文献
128.
M. Manso S. Pessanha F. Figueira S. Valadas A. Guilherme M. Afonso A. C. Rocha M. J. Oliveira I. Ribeiro M. L. Carvalho 《Analytical and bioanalytical chemistry》2009,395(7):2029-2036
The reddish-brown, brown or yellowish stains of circular or irregular shape known as foxing spots have been fully described
in conservation literature but still, this phenomenon does not find any scientific agreement since many hypotheses have been
raised concerning their origin. In this work a contribution to foxing definition not only focussed on its appearance but also
reported on its chemical information. For this purpose foxing stains present in drawings from two Portuguese artists dated
from the eighteenth to nineteenth centuries were observed under ultra-violet light and optical microscope and analysed by
three non-invasive spectroscopy techniques. The observations carried out on the stains provided information on their surface
morphology. The use of energy-dispersive X-ray fluorescence revealed a variation on the elemental content between foxing and
paper region. Although the results from X-ray diffraction analysis showed no signs of cellulose degradation in foxing stains,
Fourier-transformed infrared analysis revealed the presence of oxide groups. Both the information on the chemical nature and
surface morphology of the stains achieved in this study will contribute to increase foxing formation information and develop
future protocols for conservation purposes. 相似文献
129.
Joaquim J. Júdice Hanif D. Sherali Isabel M. Ribeiro 《Computational Optimization and Applications》2007,37(2):139-156
In this paper an eigenvalue complementarity problem (EiCP) is studied, which finds its origins in the solution of a contact
problem in mechanics. The EiCP is shown to be equivalent to a Nonlinear Complementarity Problem, a Mathematical Programming
Problem with Complementarity Constraints and a Global Optimization Problem. A finite Reformulation–Linearization Technique
(Rlt)-based tree search algorithm is introduced for processing the EiCP via the lattermost of these formulations. Computational
experience is included to highlight the efficacy of the above formulations and corresponding techniques for the solution of
the EiCP. 相似文献
130.
J. J. Júdice H. D. Sherali I. M. Ribeiro A. M. Faustino 《Journal of Optimization Theory and Applications》2007,134(3):467-481
In this paper, an algorithm for solving a mathematical programming problem with complementarity (or equilibrium) constraints
(MPEC) is introduced, which uses the active-set methodology while maintaining the complementarity restrictions throughout
the procedure. Finite convergence of the algorithm to a strongly stationary point of the MPEC is established under reasonable
hypotheses. The algorithm can be easily implemented by adopting any active-set code for nonlinear programming. Computational
experience is included to highlight the efficacy of the proposed method in practice. 相似文献