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111.
C. Currò D. Fusco N. Manganaro 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2013,64(4):1227-1248
By means of a reduction approach to 2 × 2 quasilinear hyperbolic homogeneous systems of first-order PDEs, a full and exhaustive analysis of nonlinear wave interactions is achieved. The alteration in the profile as well as in the wave time distortion of the emerging pulses caused by the interaction process is illustrated in detail through exact solutions of initial value problems. Canonical forms of 2 × 2 systems which allow for special (soliton-like) hyperbolic wave interactions and of interest in applications are also determined. 相似文献
112.
113.
114.
The direct conversion of methane to methanol at low temperatures was achieved selectively using dioxiranes 1a,b either in the isolated form or generated in situ from aqueous potassium caroate and the parent ketone at a pH close to neutrality. Results suggest that the more powerful dioxirane TFDO (1b) should be the oxidant of choice. 相似文献
115.
116.
The classical Sobolev embedding theorem of the space of functions of bounded variation BV(Rn) into Ln′(Rn) is proved in a sharp quantitative form. 相似文献
117.
We consider a dilute mixture of a finite number of particles and we are interested in the coarsening of the spatial distribution in two space dimensions under Mullins-Sekerka dynamics. Under the appropriate scaling hypotheses we associate radii and centers to each particle and derive equations for the whole evolution. 相似文献
118.
M. Casalboni U. Caruso A. De Maria M. Fusco B. Panunzi A. Quatela A. Roviello F. Sarcinelli A. Sirigu 《Journal of polymer science. Part A, Polymer chemistry》2004,42(12):3013-3022
New polymers for second‐order nonlinear optical (NLO) applications were synthesized and characterized. They were distinguished by the presence of chromophore groups, with various molecular hyperpolarizability values, used as pendants on substantially rigid backbones. The polymers were prepared through the reaction of tolylene‐2,4‐diisocyanate, or a suitable alkyloxyphthaloyl dichloride, with the N,N‐diethanol‐4‐(phenyl) group azo‐linked to a nitrofluorenone, nitrostilbene, nitrooxadiazole, or nitrothiadiazole moiety. The polymers exhibited good thermal stability, high glass‐transition temperatures, and an absence of crystallinity. The second‐order NLO properties of thin, transparent poled films, prepared by spin coating and thermal corona poling, were investigated for some of the polymers. The second harmonic coefficients, ranging between 18 and 25 pm/V, depended more on the alignment of the chromophore groups along the direction of the poling field than on their molecular hyperpolarizability. The temporal stability of the NLO properties of the polymers was also investigated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3013–3022, 2004 相似文献
119.
Lower semicontinuity for polyconvex functionals of the form ∫Ω
g(detDu)dx with respect to sequences of functions fromW
1,n
(Ω;ℝ
n
) which converge inL
1 (Ωℝ
n
) and are uniformly bounded inW
1,n−1 (Ω;ℝ
n
), is proved. This was first established in [5] using results from [1] on Cartesian Currents. We give a simple direct proof
which does not involve currents. We also show how the method extends to prove natural, essentially optimal, generalizations
of these results.
Supported by MURST, Gruppo Nazionale 40%
Partially supported by Australian Research Council 相似文献
120.
Methyl(trifluoromethyl)dioxirane (TFDO, 1b), a powerful yet selective oxidant, was employed to achieve in high yield the direct stereoselective hydroxylation at tert-CH of cis,cis-1,3,5-trimethylcyclohexane (4), yielding triol 7 bearing all-axial disposition of the three OH groups. Similarly, TFDO oxidation of 1,3- and of 1,4-dimethylcyclohexane gave the corresponding Z-diols 5 and 6, respectively. Triol 7 was a convenient starting material to synthesize a novel borate—that is, 1-bora-2,8,9-trioxa-3,5,7-trimethyladamantane (8)—having a peculiar cage-shaped ‘tripod’ structure. From triol 7, novel tripod arylboronic Brönsted-assisted Lewis acids (BLA) could be obtained, as exemplified by 10a and 10b. 相似文献