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81.
J.J. Lima-Silva J. Mendes Filho M.H. Lente D. Garcia 《Solid State Communications》2004,131(2):111-114
Lead zinc niobate-lead titanate[(1−x)Pb(Zn1/3Nb2/3)O3-xPbTiO3] (PZN-PT) crystals with x=4.5% and x=12% have been investigated using dielectric and Raman measurements over a range of temperatures. Above room temperature, dielectric measurements show that both compositions exhibit structural phase transitions according to the phase diagram proposed by Kuwata et al. [Ferroelectrics 387 (1981) 579]. Below room temperature, an anomaly at around 180 K for the x=12% sample is observed, suggesting another phase transition. Raman measurements are used to study all phase transitions. 相似文献
82.
I.O. Mazali A.G. Souza Filho B.C. Viana J. Mendes Filho O.L. Alves 《Journal of nanoparticle research》2006,8(1):141-148
In this paper we report the synthesis and characterization of TiO2 nanocrystal dispersed into a porous Vycor glass. We have obtained very small TiO2 nanocrystals in the anatase form. The nanocrystal size is controlled via the mass increment only thus preventing the growth through the coalescence process. The nanocrystal size was monitored through transmission electron microscope and Raman scattering. The␣coalescence control is attributed due to the obtention of nanocrystals dispersed into the host and to the terminal bonds present in the porous which act as an anchor thus resulting in a low diffusion of the nanocrystals through the porous network. 相似文献
83.
84.
S. Cimmino E. Di Pace E. Martuscelli L. C. Mendes C. Silvestre 《Journal of Polymer Science.Polymer Physics》1994,32(12):2025-2035
The article discusses the influence of an oligomeric resin, hydrogenated oligo (cyclopentadiene) (HOCP), on the morphology and properties of its blends with high density polyethylene (HDPE). HDPE/HOCP blends after solidification contain three phases: the crystalline phase of HDPE and two amorphous phases, one rich in amorphous HDPE and the other in HOCP. DSC thermograms and the loss modulus behaviors show that the γ transition is influenced by HOCP molecules and, in addition to the αc transition of HDPE, there is another transition that is attributed to the HOCP-rich phase. The hypothesis of the two amorphous phases is confirmed by the optical microscopy observations performed on isothermally crystallized blend films. © 1994 John Wiley & Sons, Inc. 相似文献
85.
86.
87.
Díez D Sanchez JM Rodilla JM Rocha PM Mendes RS Paulino C Marcos IS Basabe P Urones JG 《Molecules (Basel, Switzerland)》2005,10(8):1005-1009
Incubation of sclareol with Rhizopus stolonifer affords in high yield a mixture of triols with 18-hydroxy-sclareol as the main component. 相似文献
88.
C. Mendes 《Algebra Universalis》2005,54(3):279-290
An Ockham algebra
that satisfies the identity
is called a Kn, m-algebra. Generalizing some results obtained in [2], J. Varlet and T. Blyth, in [3, Chapter 8], study congruences on K1, 1-algebras. In particular, they describe the complement (when it exists) of a principal congruence and characterize these congruences
that are complemented. In this paper we study the same question for Kn, m-algebras.
Received March 24, 2005; accepted in final form April 28, 2005. 相似文献
89.
H. V. Ribeiro R. S. Mendes L. C. Malacarne S. Picoli P. A. Santoro 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,75(3):327-334
A random walk-like model is considered to discuss statistical aspects of tournaments. The model is applied to soccer leagues
with emphasis on the scores. This competitive system was computationally simulated and the results are compared with empirical
data from the English, the German and the Spanish leagues and showed a good agreement with them. The present approach enabled
us to characterize a diffusion where the scores are not normally distributed, having a short and asymmetric tail extending
towards more positive values. We argue that this non-Gaussian behavior is related with the difference between the teams and
with the asymmetry of the scores system. In addition, we compared two tournament systems: the all-play-all and the elimination
tournaments. 相似文献
90.
k-Core organization of complex networks 总被引:1,自引:0,他引:1
We analytically describe the architecture of randomly damaged uncorrelated networks as a set of successively enclosed substructures--k-cores. The k-core is the largest subgraph where vertices have at least k interconnections. We find the structure of k-cores, their sizes, and their birthpoints--the bootstrap percolation thresholds. We show that in networks with a finite mean number zeta2 of the second-nearest neighbors, the emergence of a k-core is a hybrid phase transition. In contrast, if zeta2 diverges, the networks contain an infinite sequence of k-cores which are ultrarobust against random damage. 相似文献