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61.
62.
《中国物理C(英文版)》2014,(4):1-4
Abstract: The cross sections of e+e-→π+π-hc at center-of-mass energies from 3.90 to 4.42 GeV were measured by the BESIII and the CLEO-c experiments. Resonant structures are evident in the e+e-→π+π-hc line shape. The fit to the line shape results in a narrow structure at a mass of (4216±18) MeV/c2 and a width of (39±2) MeV, and a possible wide structure of mass (4293±9) MeV/c2 and width (222=k67) MeV. Here, the errors are combined statistical and systematic errors. This may indicate that the Y(4260) state observed in e+e-→π+π-J/ψ has a fine structure in it. 相似文献
63.
64.
65.
This article addresses the issue of robust sampled‐data control for a class of uncertain mechanical systems with input delays and linear fractional uncertainties which appear in all the mass, damping, and stiffness matrices. Then, a novel Lyapunov–Krasovskii functional is constructed to obtain sufficient conditions under which the uncertain mechanical system is robustly, asymptotically stable with disturbance attenuation level about its equilibrium point for all admissible uncertainties. More precisely, Schur complement and Jenson's integral inequality are utilized to substantially simplify the derivation of the main results. In particular, a set of sampled‐data controller is designed in terms of the solution of certain linear matrix inequalities that can be solved effectively using available MATLAB software. Finally, a numerical example with simulation result is provided to show the effectiveness and less conservativeness of the proposed sampled‐data control scheme. © 2014 Wiley Periodicals, Inc. Complexity 20: 19–29, 2015 相似文献
66.
《Comptes Rendus Chimie》2014,17(7-8):687-700
The influence of the presence of H2O on the contact between carbon, used as model soot, and a model four-way catalyst (1% Pt–10% BaO/Al2O3) was investigated. NOx adsorption/TPD cycles at 300 °C together with XRD, XPS and DRIFTS characterizations showed that only surface nitrate species are destabilized by the carbon present in the catalytic bed, leading to a decrease of the NOx storage capacity and carbonate species formation. In another way, injection of water in the reactive gas flow decreases also the NOx storage capacity of the catalyst, but promotes the formation of stable nitrate species. A non-cumulative effect of carbon and water was observed. It was proposed that a competition between the destabilization, by carbon, of weakly bonded surface nitrate species and the enhancement of bulk nitrate species formation in the presence of water occurs. 相似文献
67.
To study phase transition kinetics on submillisecond time scale a sensitive ultrafast nanocalorimeter was constructed. Controlled
ultrafast cooling, as well as heating, up to 106K/s was attained. The method was applied for the measurements of the superheating phenomenon in a set of linear polymers:
iPS, PBT, PET, and iPP. A power law relation between the superheating and the heating rate holds in the heating rate range
10-2-104K/s. A limiting superheating of about 10% of the melting temperature was observed at rates above 104-105K/s. This limit depends on annealing conditions before sample melting. The observed superheating limit, as well as the power
law, can be accounted for the internal stresses near the crystalline amorphous interface in semicrystalline polymers induced
by heating, which are related to the thermal expansion gradients inherent in a semicrystalline material. 相似文献
68.
Changing the orientational order in liquid-crystal
elastomers leads to internal stresses and changes of the sample
shape. When this effect is induced by light, due to
photoisomerization of constituent molecular moieties, the
photomechanical actuation results. We investigate quantitatively
how the intensity and the polarization of light affect
photoactuation. By studying dissolved, as well as covalently
bonded azo-dyes, we determine the changes in absorption and the
response kinetics. For the first time we compare the response of
aligned monodomain, and randomly disordered polydomain nematic
elastomers, and demonstrate that both have a comparable
photoresponse, strongly dependent on the polarization of light.
Polarization-dependent photoactuation in polydomain elastomers
gives an unambiguous proof of its mechanism since it is the only
experiment that distinguishes from the associated thermal
effects. 相似文献
69.
This paper investigates finite-stretching corrections
to the classical Milner-Witten-Cates theory for semi-dilute
polymer brushes in a good solvent. The dominant correction to the
free energy originates from an entropic repulsion caused by the
impenetrability of the grafting surface, which produces a
depletion of segments extending a distance μ∝L-1
from the substrate, where L is the classical brush height. The
next most important correction is associated with the
translational entropy of the chain ends, which creates the
well-known tail where a small population of chains extend beyond
the classical brush height by a distance ξ∝L-1/3.
The validity of these corrections is confirmed by quantitative
comparison with numerical self-consistent field theory. 相似文献
70.
Y.-X. Ping B. Zhang Z. Cheng 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(1):175-180
The generation of continuous variable entanglement via
atomic coherence in a two-mode three-level cascade atomic system
is discussed according to the entanglement criterion proposed by
Duan et al. [Phys. Rev. Lett. 84, 2722 (2000)].
Atomic coherence between the top and bottom levels is induced with
two photons of a strong external pump field. It shows that
entanglement for the two-mode field in the cavity can be generated
under certain conditions. Moreover, by means of the input-output
theory, we show that the two-mode entanglement could also be
approached at the output. 相似文献