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191.
In this paper we obtain some metrics results about large partial quotients in the continued fraction expansion. 相似文献
192.
M F Anjos R C H Cheng C S M Currie 《The Journal of the Operational Research Society》2004,55(5):535-541
The paper describes a methodology that has been implemented in a major British airline to find the optimal price to charge for airline tickets under one-way pricing. An analytical model has been developed to describe the buying behaviour of customers for flights over the selling period. Using this model and a standard analytical method for constrained optimization, we can find an expression for the optimal price structure for a flight. The expected number of bookings made on each day of the selling period and in each fare class given these prices can then be easily calculated. A simulation model is used to find the confidence ranges on the numbers of bookings and these ranges can be used to regulate the sale of tickets. A procedure to update the price structure based on the remaining capacity has also been developed. 相似文献
193.
C. Vaca‐Garcia G. Gozzelino W. G. Glasser M. E. Borredon 《Journal of Polymer Science.Polymer Physics》2003,41(3):281-288
The main transitions of cellulose fatty esters with different degrees of substitution (DSs) were investigated with dynamic mechanical thermal analysis. Two distinct main relaxations were observed in partially substituted cellulose esters (PSCEs). They were attributed to the glass‐transition temperature and to the chain local motion of the aliphatic substituents. The temperatures of both transitions decreased when DS or the number of carbon atoms (n) of the acyl substituent increased. Conversely, all the transitions of fully substituted cellulose esters occurred within a narrow temperature range, and they did not vary significantly with n. This phenomenon was explained by the formation of a crystalline phase of the fatty substituents. The presence of few residual OH groups in PSCEs was responsible for a large increase in the storage bending modulus, and it eliminated the effect of n on damping. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 281–288, 2003 相似文献
194.
Peter G. Casazza Gitta Kutyniok Mark C. Lammers 《Journal of Fourier Analysis and Applications》2004,10(4):383-408
Duality principles in Gabor theory such as the Ron–Shen duality principle and the
Wexler–Raz biorthogonality relations play a fundamental role for analyzing Gabor systems. In this
article we present a general approach to derive duality principles in abstract frame theory. For
each sequence in a separable Hilbert space we define a corresponding sequence dependent only
on two orthonormal bases. Then we characterize exactly properties of the first sequence in terms
of the associated one, which yields duality relations for the abstract frame setting. In the last part
we apply our results to Gabor systems. 相似文献
195.
Pierre Crispel Pierre Degond Céline Parzani Marie-Hélène Vignal 《Comptes Rendus Mathematique》2004,338(4):327-332
In this Note, we propose three formulations of a model describing a quasi-neutral plasma with non-vanishing current. In order to study and compare the numerical efficiency of each formulation, two test-problems are implemented in one dimension. The first is a periodic perturbation of a uniform stationary plasma. The second is a case of plasma expansion in vacuum between two electrodes. To cite this article: P. Crispel et al., C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
196.
Electron paramagnetic resonance (EPR) investigations has been carried out on the new family of molybdenum doped vanadium sesquioxides (V1−xMox)2−δO3. The oxidation effects were monitored from the rate of paramagnetic V4+ created when the sample is exposed to the air. The effects of the oxidation time, sample temperature, and annealing at 1000 °C under a diluted hydrogen atmosphere on the EPR signal features are analyzed. The V4+ concentration in the oxidized samples is determined and the relaxation effects driven by the conduction electrons are pointed out from the thermal behaviour of the EPR line features. EPR spectra of all the oxidized samples also reveal a small ferromagnetic contribution strongly correlated with the V4+ content. 相似文献
197.
Active noise control usually aims at reducing the total acoustic pressure due to a noise source; it may also be used in principle to reduce the scattered acoustic radiation from a reflecting body in order to render it invisible to incident acoustic waves. In this paper, a real-time control strategy is introduced to achieve, with ordinary noise sources and sensors, the effective suppression of the noise scattered by a 3-D surface. Numerical simulations of 2-D and 3-D control are used to illustrate the potential of this control strategy. Preliminary experimental results are also given for the 1-D case of a rigid body inserted into a duct. 相似文献
198.
Deformation quantization is a powerful tool for quantizing theories with bosonic and fermionic degrees of freedom. The star products involved generate the mathematical structures which have recently been used in attempts to analyze the algebraic properties of quantum field theory. In the context of quantum mechanics they provide a quantization procedure for systems with either bosonic or fermionic degrees of freedom. We illustrate this procedure for a number of physical examples, including bosonic, fermionic, and supersymmetric oscillators. We show how non-relativistic and relativistic particles with spin can be naturally described in this framework. 相似文献
199.
An analytical approach for vibration response analysis of a beam with single passive constrained layer damping (PCLD) patch is presented. The governing equation of motion of the beam is firstly derived on the basis of an energy approach and the Lagrange equation. The noval contribution is that a third admissible function is introduced to represent the longitudinal displacements of the constraining layer in the PCLD patch when the assumed-modes method is applied for discretizing the governing equation. In conventional analytical approaches, only two admissible functions are used together with a longitudinal static equilibrium equation of a section of base beam or constraining layer. Comparison of the computational results from the proposed analytical approach and the conventional analytical approach as well as a commercial FEM code reveals that the proposed analytical approach can describe the vibration responses of the damped beam more accurately for commonly used viscoelastic material (VEM) layer in the PCLD patch while the conventional analytical approach, in general, overestimates the damping effects of the PCLD patch. The advantages and disadvantages of the proposed analytical approach and conventional analytical approach are discussed through some case studies. 相似文献
200.
A method for the construction of the second constant of motion in fourth order is carried out. Correspondingly the fourth order potential equation is obtained whose solutions directly provide the classical integrable systems. Second constant of motion is obtained for a large class of potentials. Quantum invariants are also obtained with second order quantum corrections of the order O(?2) to the corresponding classical invariants. The phase space diagrams for these cases are drawn using a mathematical computer software package in two dimensions. 相似文献