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111.
Miroslav Petrović 《Graphs and Combinatorics》1999,15(2):221-232
In this paper, by means of computer checking, all simple graphs with at most two nonnegative eigenvalues, and all minimal
simple graphs with exactly two (respectively, three) nonnegative eigenvalues are determined.
Received: April 5, 1996 / Revised: May 2, 1997 相似文献
112.
113.
Černý Miroslav Šandera Pavel Pokluda Jaroslav 《Czechoslovak Journal of Physics》1999,49(10):1495-1501
Ab initio calculation of ideal strength of cubic crystals under three-axial tension was performed using the LMTO-ASA method. Computed values are in a good agreement with those obtained previously by means of semi-empirical polynomial approach. The values of equilibrium lattice parameter obtained in the framework of ab initio method are well comparable with the experimental data whereas a less satisfactory agreement was achieved in the case of bulk moduli. 相似文献
114.
Miroslav Fiedler 《Linear algebra and its applications》2006,413(1):177-188
A real matrix is called k-subtotally positive if the determinants of all its submatrices of order at most k are positive. We show that for an m × n matrix, only mn inequalities determine such class for every k, 1 ? k ? min(m,n). Spectral properties of square k-subtotally positive matrices are studied. Finally, completion problems for 2-subtotally positive matrices and their additive counterpart, the anti-Monge matrices, are investigated. Since totally positive matrices are 2-subtotally positive as well, the presented necessary conditions for this completion problem are also necessary conditions for totally positive matrices. 相似文献
115.
Hassan Eslami Miroslav Grmela Mosto Bousmina 《Journal of Polymer Science.Polymer Physics》2009,47(17):1728-1741
Evolution of the microstructure as well as the shear stress and the normal stress difference of polymer/layered silicate nanocomposites prepared by melt mixing of poly[butylene succinate‐co‐adipate] and organically modified montmorillonite are investigated in transient forward and reverse start‐up shear flows at different clay loading and different shear rates. Special attention is paid to the structure build‐up at rest and to the amplitude of the overshoots observed during the reverse start‐up test in the shear stress and the normal stress difference. The model that we have developed previously is used to suggest an explanation for the observed phenomena. The model is able to capture observed behavior of the shear stress in both forward and reverse start‐up flows. It fails, however, to predict experimentally observed overshoot in the normal stress difference. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1728–1741, 2009 相似文献
116.
Miroslav Engliš 《Journal of Fourier Analysis and Applications》2007,13(3):243-265
Toeplitz operators on the Bergman space of the unit disc can be written as integrals of the symbol against an invariant operator
field of rank-one projections. We consider a generalization of the Toeplitz calculus obtained upon taking more general invariant
operator fields, and also allowing more general domains than the disc; such calculi were recently introduced and studied by
Arazy and Upmeier, but also turn up as localization operators in time-frequency analysis (witnessed by recent articles by
Wong and others) and in representation theory and mathematical physics. In particular, we establish basic properties like
boundedness or Schatten class membership of the resulting operators. A further generalization to the setting when there is
no group action present is also discussed, and the various settings in which similar operator calculi appear are briefly surveyed. 相似文献
117.
This paper is a continuation of [11]. Here we study all identities which induce decompositions into nil-extensions of a union
of groups and identities which induce various special types of these decompositions.
Supported by Grant 0401A of SF Servia through Math. Inst. SANU. 相似文献
118.
Miroslav Hušek 《Applied Categorical Structures》2007,15(5-6):615-620
If sequential cardinals do not exist then every topological space is generated from a converging sequence by using finite
products, disjoint sums and quotients.
The author acknowledges the support of the grants MSM 0021620839 and GAČR 201/06/0933 of Czech Republic. 相似文献
119.
Vladimí ra Novotn V ra Hamplov Miroslav Ka par Milada Glogarov Damian Pociecha 《Liquid crystals》2005,32(9):1115-1123
The synthesis and physical properties of bent-shaped molecules with ester linkages and methoxy substitution on a non-central ring are presented. Terminal chains of most mesogens contain a group with double bond, which promotes polymerization. In all the compounds studied a B2 phase just below the isotropic phase has been found. Polarization current profiles indicate that this phase is antiferroelectric, and dielectric spectroscopy data with a pronounced high frequency mode support this fact. For several compound chirality switching from racemic to the homochiral state was seen after application of a low frequency a.c. field. Another phase, which could be assigned to the B7 family, appears below the B2 phase on cooling. 相似文献
120.
Let be a bounded domain with C
2 boundary. And let H
k
be the set of all polyharmonic functions f with order k on Ω. For 0<p, q≤∞ and ϕ a normal weight, the mixed-norm space consists of all function f in H
k
for which the mixed-norm ||·||
p, q, ϕ
<∞. The main result of the paper is the norm equivalence:
where x
0 is a fixed point in Ω, m is a positive integer and is the jth gradient of f. A similar result for Bloch-type spaces is also obtained.
This research is partially supported by the National Natural Science Foundation of China (10471039), the MNZŽS Grant No. 144010
(Serbia), and the Natural Science Foundation of Zhejiang Province (M103104). 相似文献