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Fulvio Ricci Giancarlo Travaglini 《Proceedings of the American Mathematical Society》2001,129(6):1739-1744
Let be a convex curve in the plane and let be the arc-length measure of Let us rotate by an angle and let be the corresponding measure. Let . Then This is optimal for an arbitrary . Depending on the curvature of , this estimate can be improved by introducing mixed-norm estimates of the form where and are conjugate exponents. 相似文献
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Mesoporous carbon catalyst supports are attractive due to their wide chemical stability while potentially increasing mass-transport through and providing a path for larger molecules to access catalytic sites. Herein we report the synthesis of a phosphorylated mesoporous carbon solid-acid catalyst characterized by NH(3)-TPD and isopropanol dehydration. 相似文献
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Fulvio Ratto Paolo Matteini Alberto Cini Sonia Centi Francesca Rossi Franco Fusi Roberto Pini 《Journal of nanoparticle research》2011,13(9):4337-4348
We investigate the photothermal conversion and transformation of gold nanoparticles with an initial dogbone shape after dispersion
in hydrated chitosan films, which is a representative model of biological tissue, and excitation by a CW diode laser for 1 min.
Gold nanodogbones are observed to undergo a distinct modification above a sharp threshold of ~11 W cm−2 and 110 °C. Surprisingly, the very same modification is achieved up to at least 36 W cm−2 and 250 °C. We use an analytical model derived from Gans theory to associate the change in color of the films with the change
in shape statistics of these gold nanoparticles. This model proves both convenient and dependable. We interpret the photothermal
transformation as a rearrangement of particles with a dogbone shape and an aspect ratio of 4.1 into rods with an aspect ratio
of 2.5, where material from the end lobes of the dogbones may relocate to the waists of the rods. In turn, additional transitions
to stable gold nanospheres may exhibit fairly slower kinetics. 相似文献
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In this paper, we discuss techniques by which the aeroacoustic properties of the turbulent flow in a rod-airfoil benchmark
experiment can be inferred from time-resolved PIV measurement. While acoustic measurements can be made directly using microphones,
the proposed techniques provide a means to directly link acoustic waves with specific flow events, which is invaluable in
devising noise mitigation strategies. The approaches are possible thanks to recent improvements in digital and camera technology
that can provide time-resolved measurements in air flows, necessary for the determination of unsteady flow quantities related
to aeroacoustic production. Both techniques are based on Curle’s acoustic analogy, where one is based on Lagrangian determination
of the required quantities, while the other requires all flow quantities to be converted into Fourier modes. Application of
both techniques yields results that are in reasonable agreement with microphone noise measurements for the rod-airfoil experiment. 相似文献
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Anna Laura Segre Fulvio Andruzzi Corrado Barone Massimo Paci Pier Luigi Magagnini 《Journal of Polymer Science.Polymer Physics》1985,23(12):2611-2621
The 13C NMR spectra of aromatic comblike polyesters obtained from 1,2-icosanediol and isomeric phthalic acids are reported and discussed. The analysis shows that the most informative spectral regions are those of the carbonyl and quaternary carbon resonances, whose peak multiplicities have been interpreted in terms of dyad and triad sequences. The results indicate that the extent of structural characterization possible for the polymers examined is dependent on the type of isomerism of the aromatic acid involved. 相似文献