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51.
We introduce multipole soliton complexes in optical lattices induced by nondiffracting parabolic beams. Despite the symmetry breaking dictated by the curvature of the lattice channels, we find that complex, asymmetric higher-order states can be stable. The unique topology of parabolic lattices affords new types of soliton motion: single solitons launched into the lattice with nonzero transverse momentum perform periodic oscillations along parabolic paths. 相似文献
52.
We address vortex solitons supported by optical lattices featuring modulation of both the linear and nonlinear refractive indices. We find that when the modulation is out of phase the competition between both effects results in remarkable shape transformations of the solitons that profoundly affect their properties and stability. Nonlinear refractive index modulation is found to impose restrictions on the maximal power of off-site solitons, which are shown to be stable only below a maximum nonlinearity modulation depth. 相似文献
53.
We propose a protocol for a controlled experiment to measure a weak value of the electron's spin in a solid state device. The weak value is obtained by a two step procedure--weak measurement followed by a strong one (postselection), where the outcome of the first measurement is kept provided a second postselected outcome occurs. The setup consists of a double quantum dot and a weakly coupled quantum point contact to be used as a detector. Anomalously large values of the spin of a two electron system are predicted, as well as negative values of the total spin. We also show how to incorporate the adverse effect of decoherence into this procedure. 相似文献
54.
Konstantin V. Pochivalov Yaroslav V. Kudryavtsev Tatyana N. Lebedeva Lyubov A. Antina Anna N. Ilyasova Mikhail Yu. Yurov Andrey V. Basko Alexander E. Zavadskii 《Journal of Thermal Analysis and Calorimetry》2018,131(3):2225-2233
Constructing phase diagrams for the mixtures of semicrystalline polymers and low molecular mass substances by DSC can meet with difficulties in the case of slow polymer crystallization. A problem of this kind is encountered for high-energy compositions poly[3,3-bis(azidomethyl)oxetane] (PBAMO)–2,4-dinitro-2,4-diazapentane (DNAP). In this study, the experimental phase diagram PBAMO–DNAP is constructed by an optical method, which makes it possible to visualize structural transformations. The kinetic studies by DSC and XRD reveal that 30–50 days of storing a homogenized PBAMO–DNAP mixture at room temperature are needed to attain stationary values of the crystallinity degree and heat of fusion. Even after that, the DSC method cannot deliver a solubility curve of DNAP in PBAMO, which is naturally generated by the optical method. This curve separates a domain of physical gels, effectively crosslinked by polymer crystallites and swollen with the plasticizer molecules, from a two-phase domain, in which the above gel reaches osmotic equilibrium with the pure plasticizer. It is also shown that the melting temperature of DNAP drops with growing the PBAMO content in the mixture, which is consistent with a decrease in the mean size of plasticizer crystals formed in polymer pores during the previous cooling. 相似文献
55.
Victor N. Bagratashivli Svetlana I. Tsypina Victor A. Radtsig Aleksey O. Rybaltovskii Pavel V. Chernov Sergey S. Alimpiev Yaroslav O. Simanovskii 《Journal of Non》1995,180(2-3):221-229
Photochemical and photoluminescence studies of oxygen-deficient centers stabilized in the bulk and on the surface of silica glasses clearly demonstrate the inhomogeneous nature of the absorption and luminescence spectra of oxygen-deficient centers. The conclusion is drawn that the inhomogeneity of the absorption spectra is due to the dispersion of the energy of the S0-S1 transition, while the inhomogeneity of the luminescence spectra is due to the dispersion of the energy barrier of intersystem crossing. The inhomogeneous nature of the oxygen-deficient centers in silica glasses is assumed to be caused by a small dispersion in the geometrical parameters of different groups of centers with similar chemical properties. 相似文献
56.
Jiang JX Su F Niu H Wood CD Campbell NL Khimyak YZ Cooper AI 《Chemical communications (Cambridge, England)》2008,(4):486-488
High surface area porous poly(phenylene butadiynylene) networks were obtained (BET surface area up to 842 m(2) g(-1)) by the palladium-catalyzed homocoupling of 1,3,5-triethynylbenzene and 1,4-diethynylbenzene. 相似文献
57.
Framework functionalisation triggers metal complex binding 总被引:1,自引:0,他引:1
Ingleson MJ Barrio JP Guilbaud JB Khimyak YZ Rosseinsky MJ 《Chemical communications (Cambridge, England)》2008,(23):2680-2682
Post-synthetic derivatisation of a porous material produces a functionalized material that binds the metal complex V(O)acac2, in contrast to the unfunctionalized precursor, which is inactive for complex binding. 相似文献
58.
59.
Perfluoro-2-ethyl-2-phenylbenzocyclobutenone heated with SbF5 at 70 °C and then treated with water, forms perfluoro-3-ethyl-3-phenylphthalide. In contrast to this, heating of perfluoro-2,2-diethylbenzo-cyclobutenone with SbF5 at 70 °C gives, after treatment of the reaction mixture with water, perfluoro-2-(pent-2-en-3-yl)benzoic acid. When the reaction temperature is raised to 125 °C, a solution of a salt of perfluoro-4-ethyl-3-methylisochromenyl cation is obtained. Hydrolysis of the solution of the salt gives perfluoro-4-ethyl-3-methylisochromen-1-one. 相似文献
60.
Evdokimov IN Efimov YO Losev AP Novikov MA 《Langmuir : the ACS journal of surfaces and colloids》2008,24(14):7124-7131
Emulsions of water in as-recovered native crude oils of diverse geographical origin evidently possess some common morphological features. At low volume fractions varphi of water, the viscosity behavior of emulsions is governed by the presence of flocculated clusters of water droplets, whereas characteristic tight gels, composed of visually monodisperse small droplets, are responsible for the viscosity anomaly at varphi approximately 0.4-0.5. Once formed, small-droplet gel domains apparently retain their structural integrity at higher varphi, incorporating/stabilizing new portions of water as larger-sized droplets. The maximum hold-up of disperse water evidently is the close-packing limit of varphi approximately 0.74. At higher water contents (up to varphi approximately 0.83), no inversion to O/W morphology takes place, but additional water emerges as a separate phase. The onset of stratified flow (W/O emulsion gel + free water) is the cause of the observed viscosity decrease, contrary to the conventional interpretation of the viscosity maximum as a reliable indicator of the emulsion inversion point. 相似文献