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81.
82.
D. Prevosto S. Napolitano P. Pingue S. Capaccioli M. Lucchesi 《The European physical journal. Special topics》2007,141(1):193-198
We studied dynamic properties of ultrathin films of
poly(ethylene terephthalate) spincoated on different substrates, by means of
dielectric spectroscopy and surface patterning experiments. We did not
observe any variations of structural dielectric relaxation dynamics for
films spincoated on aluminium substrate having thicknesses down to 40 nm. On
the same substrate, 13 nm thick films are instead characterized by a
reduction of the chains mobility. Surprisingly the chains dynamics as probed
by a surface nanopatterning experiment evidenced a strong dependence on the
substrate interaction even for 50 nm thick films, where dielectric
relaxation dynamics is unaffected. It can be deduced that different length
scales characterise dielectric relaxation dynamics and the processes related
to the surface patterning, even if both are related to the chain mobility.
Further experiments are wished to better understand this intriguing
scenario. 相似文献
83.
Ali A. Alhazime M. ME. Barakat Radiyah A. Bahareth E. M. Mahrous Saad Aldawood S. Abd El Aal and S. A. Nouh 《中国物理 B》2022,31(9):97802-097802
We applied an ex-situ casting procedure to prepare a nanocomposite (NCP) from Makrofol polycarbonate (PC) and CdSe nanoparticles. The CdSe nanoparticles were prepared by a thermolysis procedure in the presence of N2 gas flow. Rietveld refinement of x-ray data illustrated that the CdSe adopts a cubic zinc blend structure of 6.057 Å lattice parameter and 2 nm typical grain size. Samples from the prepared NCP were exposed to γ dosages (20 kGy-250 kGy). The modifications induced in the NCP films owing to γ dosages have been studied. The γ irradiation (50 kGy-250 kGy) causes crosslinks that reduce the optical bandgap from 4.15 eV to 3.81 eV, associated with an increase in dielectric parameters and refractive index. This is attributed to an increase in the mass fraction of the disordered regions as specified by x-ray diffraction. The PC-CdSe NCP was found to have a reaction to color modification which makes it suitable for saleable reproduction on a printing press. 相似文献
84.
Ear Decompositions of Matching Covered Graphs 总被引:3,自引:0,他引:3
G different from and has at least Δ edge-disjoint removable ears, where Δ is the maximum degree of G. This shows that any matching covered graph G has at least Δ! different ear decompositions, and thus is a generalization of the fundamental theorem of Lovász and Plummer
establishing the existence of ear decompositions. We also show that every brick G different from and has Δ− 2 edges, each of which is a removable edge in G, that is, an edge whose deletion from G results in a matching covered graph. This generalizes a well-known theorem of Lovász. We also give a simple proof of another
theorem due to Lovász which says that every nonbipartite matching covered graph has a canonical ear decomposition, that is,
one in which either the third graph in the sequence is an odd-subdivision of or the fourth graph in the sequence is an odd-subdivision of . Our method in fact shows that every nonbipartite matching covered graph has a canonical ear decomposition which is optimal,
that is one which has as few double ears as possible. Most of these results appear in the Ph. D. thesis of the first author
[1], written under the supervision of the second author.
Received: November 3, 1997 相似文献