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31.
We investigate the influence of the type of light polarization (linear or circular) on the efficiency of non-linear optical
processes in photoanisotropic materials. A theoretical model of photoprocesses in materials in which optical non-linearity
is related to absorbing centres with intrinsic linear anisotropy is constructed. Theoretical calculations show that the photostationary
concentration of the photoproducts (and the mean values of the non-linear changes in optical constants) in these materials
is higher if the exciting light is circularly polarized. Experimental results on non-linear processes in samples of fluorescein
incorporated in orthoboric acid and in azodye/polymer layers are in good agreement with the theory.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
32.
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34.
A Hanle signal is observed in the absorption of a cell filled with nitrogen dioxide NO2 at room temperature. The excitation was performed by an Ar+ laser at a wavelength of 476.4 nm. 相似文献
35.
Quantum cascade devices processed into double metal cavities with subwavelength thickness and a grating on top are studied at terahertz frequencies. The power extracted from the devices as a function of the device thickness and the grating period is analyzed owing to electrodynamical modeling of dipole emission based on a modal method in multilayer systems. The experimental data thus reveal a strong Purcell enhancement, with Purcell factors up to approximately 50. 相似文献
36.
Androulakis J Todorov I He J Chung DY Dravid V Kanatzidis M 《Journal of the American Chemical Society》2011,133(28):10920-10927
We report promising thermoelectric properties of the rock salt PbSe-PbS system which consists of chemical elements with high natural abundance. Doping with PbCl(2), excess Pb, and Bi gives n-type behavior without significantly perturbing the cation sublattice. Thus, despite the great extent of dissolution of PbS in PbSe, the transport properties in this system, such as carrier mobilities and power factors, are remarkably similar to those of pristine n-type PbSe in fractions as high as 16%. The unexpected finding is the presence of precipitates ~2-5 nm in size, revealed by transmission electron microscopy, that increase in density with increasing PbS concentration, in contrast to previous reports of the occurrence of a complete solid solution in this system. We report a marked impact of the observed nanostructuring on the lattice thermal conductivity, as highlighted by contrasting the experimental values (~1.3 W/mK) to those predicted by Klemens-Drabble theory at room temperature (~1.6 W/mK). Our thermal conductivity results show that, unlike in PbTe, optical phonon excitations in PbSe-PbS systems contribute to heat transport at all temperatures. We show that figures of merit reaching as high as ~1.2-1.3 at 900 K can be obtained, suggesting that large-scale applications with good conversion efficiencies are possible from systems based on abundant, inexpensive chemical elements. 相似文献
37.
Associated with a finite-dimensional algebra of global dimension at most 2, a generalized cluster category was introduced in Amiot (2009) [1]. It was shown to be triangulated, and 2-Calabi–Yau when it is Hom-finite. By definition, the cluster categories of Buan et al. (2006) [4] are a special case. In this paper we show that a large class of 2-Calabi–Yau triangulated categories, including those associated with elements in Coxeter groups from Buan et al. (2009) [7], are triangle equivalent to generalized cluster categories. This was already shown for some special elements in Amiot (2009) [1]. 相似文献
38.
S. Yu. Pilyugin G. I. Vol’fson D. I. Todorov 《Vestnik St. Petersburg University: Mathematics》2011,44(3):208-213
In this paper, the notion of the Lipschitz inverse shadowing property with respect to two classes of d-methods that generate pseudotrajectories of dynamical systems is introduced. It is shown that if a diffeomorphism of a Euclidean space has the Lipschitz inverse shadowing property on the trajectory of an individual point, then the Mañé analytic strong transversality condition must be satisfied at this point. This result is used in the proof of the main theorem: a diffeomorphism of a smooth closed manifold that has the Lipschitz inverse shadowing property is structurally stable. 相似文献
39.
P.-L. Chau K.M. Tu K.K. Liang I.T. Todorov S.J. Roser Robert Barker 《Molecular physics》2013,111(13):1461-1467
Halothane binding to hydrated dimyristoylphosphatidylcholine (DMPC) bilayer membranes has been examined over a wide range of pressures from 105 to 4?×?108?Pa. We show that the solvation of halothane by the membrane and bulk water are both pressure dependent, with an increased pressure driving halothane into the membrane. Analysis of these results shows that this pressure dependence is not the cause of pressure reversal, the process whereby general anaesthetics lose their efficacy at pressures of about 8?×?106 to about 2.5?×?107?Pa. 相似文献
40.
This paper analyzes the effect on the optimal value of a given linear semi-infinite programming problem of the kind of perturbations which more frequently arise in practical applications: those which affect the objective function and the right-hand-side coefficients of the constraints. In particular, we give formulae which express the exact value of a perturbed problem as a linear function of the perturbation. 相似文献