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161.
We investigate the connection between the asymmetry of the Fano resonances in a mesoscopic interferometer with an embedded quantum dot and the π lapses in the phase of the “bare” dot transmittance. Consecutive Fano resonances with the same (opposite) sign of the Fano parameter imply the presence (absence) of a phase lapse with π between the corresponding resonances of the dot. Our results suggest that the famous “phase lapse” problem, first reported by Schuster et al. [R. Schuster, E. Buks, M. Heiblum, D. Mahalu, V. Umansky, H. Shtrikman, Nature 385 (1997) 417], can therefore be experimentally addressed in closed interferometers. It is also proposed that the Fano effect can be used to extract the phase distributions of the eigenfunctions for a mesoscopic 2D shape, via the parity of the resonances. In the presence of electron–electron interaction, one can calculate the phases of the T-matrix elements. The numerical results lead to the same conclusions as for the non-interacting case. 相似文献
162.
Stoica-Guzun A Stroescu M Jinga S Jipa I Dobre T Dobre L 《Ultrasonics sonochemistry》2012,19(4):909-915
The effect of ultrasonic irradiation (40 kHz) on the calcium carbonate deposition on bacterial cellulose membranes was investigated using calcium chloride (CaCl2) and sodium carbonate (Na2CO3) as starting reactants. The composite materials containing bacterial cellulose-calcium carbonate were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and color measurements. The polymorphs of calcium carbonate that were deposited on bacterial cellulose membranes in the presence or in the absence of ultrasonic irradiation were calcite and vaterite. The morphology of the obtained crystals was influenced by the concentration of starting solutions and by the presence of ultrasonic irradiation. In the presence of ultrasonic irradiation the obtained crystals were bigger and in a larger variety of shapes than in the absence of ultrasounds: from cubes of calcite to spherical and flower-like vaterite particles. Bacterial cellulose could be a good matrix for obtaining different types of calcium carbonate crystals. 相似文献
163.
Gheorghita Zbancioc Ionel I. Mangalagiu Costel Moldoveanu 《Molecules (Basel, Switzerland)》2022,27(19)
Azaheterocycles rings with five and six members are important tools for the obtaining of fluorescent materials and fluorescent sensors. The relevant advances in the synthesis of azaheterocyclic derivatives and their optical properties investigation, particularly in the last ten years, was our main objective on this review. The review is organized according to the size of the azaheterocycle ring, 5-, 6-membered and fused ring azaheterocycles, as well as our recent contribution on this research field. In each case, the reaction pathways with reaction condition and obtained yield, and evaluation of the optical properties of the obtained products were briefly presented. 相似文献
164.
N. N. Syrbu S. I. Radautsan R. V. Cretu V. E. Tezlevan N. A. Moldoveanu 《Crystal Research and Technology》1996,31(3):307-314
Raman and infrared reflectivity spectra of CdInGaS4, CdIn2G4, HgInGaS4, and CdIn2S2Se2 crystals have been investigated. The fiindamental phonon parameters, the limiting dielectric constants ϵ0 and ϵ∞ and the reflectivity spectrum contours have been calculated using classical dispersion relations. 相似文献