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81.
超图的Laplacian 总被引:1,自引:0,他引:1
本文讨论了由F.R.K.Chung 引入的k-图的Laplacian 的一些基本性质.通过引入k-图的邻接图的概念,得到了k-图的Laplacian 及其特征多项式的更明确的表达式.同时,也改进了文[1]中关于d-正则k-图的谱值的一个下界 相似文献
82.
《Physics letters. A》2020,384(32):126795
The effects of diameter variation as a result of composition modulation along a nanowire on the confined energy states of electrons have been investigated theoretically. Possible confined states have been predicted by examining an effective potential term. Our results indicate that for a given radius of the wire, there exists a critical radius for modulation part below which carriers could not bound to the modulated part. The critical radius increases and reaches a limiting value as wire radius increases, specifying that the bound states could survive even when the radius of modulation decreases below the radius of remaining wire. Also, application of magnetic field could affect the critical radius so that the confinements to the modulated part are suppressed gradually by increasing the field strength, which is a sign of type-I to type-II transitions. Examination of results by the numerically solving the Schrodinger equation confirms the analytical predictions. 相似文献
83.
矩阵复合型谱包含域的改进及应用 总被引:1,自引:0,他引:1
本文研究了矩阵的复合型谱包含域,给出了边界定理,得到了改进的复合型谱包含域,作为应用得到了非奇异H-矩阵的更精确的判别条件. 相似文献
84.
Tian Zhengping 《东北数学》1994,(2)
OntheProblemofHeilbronType¥TianZhengping(田正平)(DepartmentofMathematics,RoyalHollowayandBedfordNewColege,UniversityofLondon,Egh... 相似文献
85.
样本均值Bootstrap逼近的收敛速度 总被引:1,自引:0,他引:1
本文进一步研究Bootstrap逼近的收敛速度,在随机变量的(2+δ)阶矩(0≤δ<2)有限的情况下,讨论标准化样本均值的分布与它的Bootstrap逼近之间差的一致收敛速度,以及这种逼近与正态分布之间差的一致收敛速度。 相似文献
86.
本文给出并证明了Ramsey数r(k,l)的一个新下界公式r(k,l)≥1.5(k-1)(l-1),此下界公式与文献[1,2]所给出的下界公式r(k,l)>(n2^n/2)/(e√2,n=min(k,l)相比,当k,l较小时,或k,l相差较大明要优越。 相似文献
87.
Airport management: taxi planning 总被引:4,自引:0,他引:4
Ángel G. Marín 《Annals of Operations Research》2006,143(1):191-202
The Taxi Planning studies the aircraft routing and scheduling on the airport ground. This is a dynamic problem, which must be updated almost every time that a new aircraft enters or exits the system. Taxi Planning has been modelled using a linear multicommodity flow network model with side constraints and binary variables. The flow capacity constraints are used to represent the conflicts and competence between aircrafts using a given airport capacity. The “Branch and Bound” and “Fix and Relax” methodologies have been used. The computational tests have been run at the Madrid-Barajas airport, using actual data from the airport traffic. 相似文献
88.
In this paper we develop, analyze, and test a new algorithm for the global minimization of a function subject to simple bounds
without the use of derivatives. The underlying algorithm is a pattern search method, more specifically a coordinate search
method, which guarantees convergence to stationary points from arbitrary starting points. In the optional search phase of
pattern search we apply a particle swarm scheme to globally explore the possible nonconvexity of the objective function. Our
extensive numerical experiments showed that the resulting algorithm is highly competitive with other global optimization methods
also based on function values.
Support for Luís N. Vicente was provided by Centro de Matemática da Universidade de Coimbra and by FCT under grant POCI/MAT/59442/2004. 相似文献
89.
We use phenomenological nonlocal Lagrangians, which lead to nontrivial forms for the quark propagator, to describe the pion.
We define a procedure based on previous studies on nonlocal Lagrangians for the calculation of the pion parton distributions
at low Q2. The obtained parton distributions fulfill all the wishful properties. Using a convolution approach we incorporate the composite
character of the constituent quarks. We evolve, using the Renormalization Group, the calculated parton distributions to the
experimental scale and compare favorably with the data and draw conclusions. 相似文献
90.
Bakhtyar Ali Abdul K. Rumaiz Arif Ozbay Edmund R. Nowak S. Ismat Shah 《Solid State Communications》2009,149(47-48):2210-2214
Pulse laser deposited (PLD) thin films of Co doped TiO2 on silicon and quartz substrates are investigated. A mixture (1:1) of argon and oxygen with various total pressures (6.6 mPa to 53 Pa) is used to vary the oxygen content in the samples. The crystal structure and transport/ magnetic properties of CoxTi1−xO2−δ (x=0.01, 0.03, 0.06) thin films are found to have strong dependence on oxygen stoichiometry. X-ray diffraction (XRD) data reveal mixed phase material containing both anatase and rutile. However, the stability of each phase depends on the amount of oxygen present in the chamber during the growth of the films. X-ray Photoelectron Spectroscopy (XPS) shows the incorporation of Co in TiO2 and is in the 2+ oxidation state. There occurs an enhancement in electrical conductivity and magnetization due to the off stoichiometric oxygen. The resistivity data follow a simple thermal activation model, giving carriers’ activation energies in the range of 20 to 140 meV. A bound magnetic polaron model is adopted to explain the observed magnetic behavior of the films. 相似文献