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81.
Christos Tatakis Apostolos Thoma 《Journal of Combinatorial Theory, Series A》2011,118(5):1540-1548
The universal Gröbner basis of an ideal is a Gröbner basis with respect to all term orders simultaneously. We characterize in graph theoretical terms the elements of the universal Gröbner basis of the toric ideal of a graph. We also provide a new degree bound. Finally, we give examples of graphs for which the true degrees of their circuits are less than the degrees of some elements of the Graver basis. 相似文献
82.
Paul G. Mezey 《Journal of mathematical chemistry》2009,45(2):550-556
Based on a comparison of nuclear charges combined with a convexity property of Hamiltonians, and employing nuclear charge
transformations representing a limited case of the Universal Molecule Model, simple electronic energy relations are obtained
for the unit cells of polymeric boron–nitrogen analogues of carbon-based nanoneedles and spiral graphite structures. 相似文献
83.
B. Jourdain 《Methodology and Computing in Applied Probability》2000,2(1):69-91
In this paper, we explain how to associate a nonlinear martingale problem with some nonlinear parabolic evolution equations starting at bounded signed measures. Our approach generalizes the classical link made when the initial condition is a probability measure. It consists in giving to each sample-path a signed weight which depends on the initial position. After dealing with the classical McKean-Vlasov equation as an introductory example, we are interested in a viscous scalar conservation law. We prove uniqueness for the corresponding nonlinear martingale problem and then obtain existence thanks to a propagation of chaos result for a system of weakly interacting diffusion processes. Last, we study the behavior of the associated fluctuations and present numerical results which confirm the theoretical rate of convergence. 相似文献
84.
Hugh L. Montgomery 《Proceedings Mathematical Sciences》1987,97(1-3):239-245
We consider the error term in the mean value estimate of Euler’s phi function ψ(n), and show that it is Ω+- (x(log log x)1/2). This improves on the earlier results of Pillai and Chowla, and of Erdös and Shapiro. 相似文献
85.
XIA Hui TANG Gang LI Yi-Fan 《理论物理通讯》2008,50(7):227-230
Based on the scaling idea of local slopes by Lopez et al. [Phys. Rev. Lett. 94 (2005) 166103], we investigate anomalous dynamic scaling of (d + 1)-dimensional surface growth equations with spatially and temporally correlated noise. The growth equations studied include the Kardar-Parisi-Zhang (KPZ), Sun-Guo-Grant (SGG), and Lai-Das Sarma-Villain (LDV) equations. The anomalous scaling exponents in both the weak- and strong-coupling regions are obtained, respectively. 相似文献
86.
A novel diagnostic method to characterize the flow patterns in an 80 mm-i.d. L-valve had been developed by using multi-resolution analysis (MRA) of wavelet transformation on the pressure fluctuation signals which were acquired from the standpipe and the horizontal part of L-valve. Parameters including the aeration rate, aeration positions, riser gas velocity and composition of binary particle mixture (194-μm and 937-μm sand particles) were used to investigate the relationship of performance of L-valve and its pressure fluctuations. By means of MRA, the original pressure fluctuations were divided into multi-scale signals. They were macro-scale, meso-scale and micro-scale successfully described the structures of gas–solid flow in the L-valve, such as the gas bubbles/slugs, dune-ripple flow, suspension particle flow, etc. 相似文献
87.
The random forced Navier--Stokes equation can be obtained as a variational problem of a proper action. By virtue of incompressibility, the integration over transverse components of the fields allows to cast the action in the form of a large deviation functional. Since the hydrodynamic operator is nonlinear, the functional integral yielding the statistics of fluctuations can be practically computed by linearizing around a physical solution of the hydrodynamic equation. We show that this procedure yields the dimensional scaling predicted by K41 theory at the lowest perturbative order, where the perturbation parameter is the inverse Reynolds number. Moreover, an explicit expression of the prefactor of the scaling law is obtained. 相似文献
88.
David A. Croydon 《Probability Theory and Related Fields》2008,140(1-2):207-238
In this article, we prove global and local (point-wise) volume and heat kernel bounds for the continuum random tree. We demonstrate
that there are almost–surely logarithmic global fluctuations and log–logarithmic local fluctuations in the volume of balls
of radius r about the leading order polynomial term as r → 0. We also show that the on-diagonal part of the heat kernel exhibits corresponding global and local fluctuations as t → 0 almost–surely. Finally, we prove that this quenched (almost–sure) behaviour contrasts with the local annealed (averaged
over all realisations of the tree) volume and heat kernel behaviour, which is smooth.
相似文献
89.
Light scattering near and from interfaces using evanescent wave and ellipsometric light scattering 总被引:1,自引:0,他引:1
The broad range of interface light scattering investigations in recent years shows the power and the versatility of these techniques to address new and open questions in colloid and interface science and the soft condensed matter field. Structural information for polymers, liquid crystals, or colloids close to planar or spherical colloidal interfaces are either captured with long range light scattering resolution, or in a complementary approach by high resolution ellipsometric techniques. Of special interest is the dynamic behavior close to or in interfaces, since it determines material properties and responses to external fields. Due to the broad dynamical range and the high scattering contrast for visible light, interface light scattering is a key to elucidate soft matter interfacial dynamics. This contribution reviews experimental and related theoretical approaches for interface light scattering and further gives an overview of achievements based on such techniques. 相似文献
90.
B. A. van Tiggelen 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(2):261-269
In this work we apply field regularization techniques to formulate a number of new phenomena related to momentum induced by
electromagnetic zero-point fluctuations. We discuss the zero-point momentum associated with magneto-electric media, with moving
media, and with
magneto-chiral media. 相似文献