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21.
I. V. Golosovsky O. P. Smirnov R. G. Delaplane A. Wannberg Y. A. Kibalin A. A. Naberezhnov S. B. Vakhrushev 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,54(2):211-216
By neutron diffraction it was shown that nanostructured Se confined within a porous glass matrix exists in a
crystalline as well as in an amorphous state. The spontaneous crystallization of crystalline Se from confined amorphous
phase was observed. The root-mean-square amplitudes of the atomic motions in the bulk as well as in confinement are found
to be essentially different in a basal plane and in the perpendicular direction along the hexagonal axis. The atomic
motions in the confined Se differ from the atomic motions in the bulk at low temperatures. The results shows an unusual
“freezing" of the atomic motion along the chains, while the atomic motions in the perpendicular plane still keep. This
“freezing" is accompanied by the deformation of nanoparticles and the appearance of inner stresses. This effect is
attributed to the interaction of confined nanoparticle with the cavity walls. 相似文献
22.
Chellachamy Anbalagan Amarnath Sitansu Sekhar Nanda Georgia C. Papaefthymiou Dong Kee Yi Ungyu Paik 《固体与材料科学评论》2013,38(1):1-56
Nanomaterials have attracted much attention from academic to industrial research. General methodologies are needed to impose architectural order in low-dimensional nanomaterials composed of nanoobjects of various shapes and sizes, such as spherical particles, rods, wires, combs, horns, and other non specified geometrical architectures. These nanomaterials are the building blocks for nanohybrid materials, whose applications have improved and will continuously enhance the quality of the daily life of mankind. In this article, we present a comprehensive review on the synthesis, dimension, properties, and present and potential future applications of nanomaterials and nanohybrids. Due to the large number of review articles on specific dimension, morphology, or application of nanomaterials, we will focus on different forms of nanomaterials, such as, linear, particulate, and miscellaneous forms. We believe that almost all the nanomaterials and nanohybrids will come under these three categories. Every form or dimension or morphology has its own significant properties and advantages. These low-dimensional nanomaterials can be integrated to create novel nano-composite material applications for next-generation devices needed to address the current energy crisis, environmental sustainability, and better performance requirements. We discuss the synthesis, properties, and morphology of different forms of nanomaterials (building blocks). Moreover, we elaborate on the synthesis, modification, and application of nanohybrids. The applications of these nanomaterials and nanohybrids in sensors, solar cells, lithium batteries, electronic, catalysis, photocatalysis, electrocatalysis, and bio-based applications will be detailed. The time is now ripe to explore new nanohybrids that use individual nanomaterial components as basic building blocks, potentially affording additionally novel behavior and leading to new, useful applications. In this regard, the combination or integration of linear nanorods/nanowires and spherical nanoparticles to produce mixed-dimensionality, higher-level nanocomposites of greater complexity is an interesting theme, which we explore in this review article. 相似文献
23.
Victor Barsan 《哲学杂志》2013,93(2):190-207
AbstractThe eigenvalue equations for the energy of bound states of a particle in a square well are solved, and the exact solutions are obtained, as power series. Accurate analytical approximate solutions are also given. The application of these results in the physics of quantum wells are discussed, especially for ultra-thin metallic films, but also in the case of resonant cavities, heterojunction lasers, revivals and super-revivals. 相似文献
24.
Ulrich Maas 《Entropy (Basel, Switzerland)》2020,22(12)
Chemical kinetics govern the dynamics of chemical systems leading towards chemical equilibrium. There are several general properties of the dynamics of chemical reactions such as the existence of disparate time scales and the fact that most time scales are dissipative. This causes a transient relaxation to lower dimensional attracting manifolds in composition space. In this work, we discuss this behavior and investigate how a time reversal effects this behavior. For this, both macroscopic chemical systems as well as microscopic chemical systems (elementary reactions) are considered. 相似文献
25.
An exciton gas on a lattice is analysed in terms of a convergent hopping expansion. For a given chemical potential, our calculation provides a sufficient condition for the hopping rate to obtain an exponential decay of the exciton correlation function. This result indicates the existence of a Mott phase in which strong fluctuations destroy the long range correlations in the exciton gas at any temperature, either by thermal or by quantum fluctuations. 相似文献
26.
Fluid and plastic flow dynamics of the critical state for a strongly pinned 2D superconductor 总被引:2,自引:0,他引:2
D. Monier L. Fruchter 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,17(2):201-205
The frequency of the Raman active A1g radial breathing mode has been widely used as a tool to estimate the distribution of diameters of single wall carbon nanotubes
(SWNT). However, the relation between frequency and diameter is not straightforward and results are model-dependent. Because
most of the experiments are performed on bundles and not on isolated tubes, the model should especially take into account
the van der Waals intertube interactions. Here, we use a pair-potential approach to account for such interactions and we derive
a nonlinear relation between the SWNT diameter and the frequency of the A1g radial breathing modes. We demonstrate a good agreement between calculations and the diameters derived from diffraction experiments
on the same samples.
Received 22 December 1999 and Received in final form 17 July 2000 相似文献
27.
A. Milekhin N.P. Stepina A.I. Yakimov A.I. Nikiforov S. Schulze D.R.T. Zahn 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(2):355-359
Self-organised Ge dot superlattices grown by molecular beam epitaxy of Ge and Si layers utilizing Stranski-Krastanov growth
mode were investigated by Raman spectroscopy. An average size of Ge quantum dots was obtained from transmission electron microscopy
measurements. The strain and interdiffusion of Ge and Si atoms in Ge quantum dots were estimated from the analysis of frequency
positions of optical phonons observed in the Raman spectra. Raman scattering by folded longitudinal acoustic phonons in the
Ge dot superlattices was observed and explained using of elastic continuum theory.
Received 25 January 2000 相似文献
28.
M. Sassetti F. Napoli B. Kramer 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,11(4):643-654
Using the bosonization technique, a theory for the collective excitations of the interacting electrons in quantum wires with
two subbands occupied is developed. The dispersion relations for the inter-subband charge and spin density excitations are
determined. The results are used to interpret the features observed in recent measurements of the Raman spectra of AlGaAs/GaAs
quantum wires, particularly for photon energies near band gap resonance. It is shown that peaks previously identified as “single
particle excitations” are signatures of higher order collective spin density excitations. Predictions about the observability
of the interband modes are made.
Received 8 February 1999 相似文献
29.
H.-K. Zhao J. Wang 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,9(3):513-524
The time-dependent transport through an ultrasmall quantum dot coupling to two electron reservoirs is investigated. The quantum
dot is perturbed by a quantum microwave field (QMF) through gate. The tunneling current formulae are obtained by taking expectation
values over coherent state (CS), and SU(1,1) CS. We derive the transport formulae at low temperature by employing the nonequilibrium
Green function technique. The currents exhibit coherent behaviors which are strongly associated with the applied QMF. The
time-dependent currents appear compound effects of resonant tunneling and time-oscillating evolution. The time-averaged current
and differential conductance are calculated, which manifest photon-assisted behaviors. Numerical calculations reveal the similar
properties as those in classical microwave field (CMF) perturbed system for the situations concerning CS and squeezed vacuum
SU(1,1) CS. But for other squeezed SU(1,1) CS, the tunneling behavior is quite different from the system perturbed by a single
CMF through gate. Due to the quantum signal perturbation, the measurable quantities fluctuate fiercely.
Received 28 May 1998 相似文献
30.
Toward computationally efficient combustion DNS with complex fuels via principal component transport
Opeoluwa Owoyele 《Combustion Theory and Modelling》2017,21(4):770-798
We investigate the potential of accelerating chemistry integration during the direct numerical simulation (DNS) of complex fuels based on the transport equations of representative scalars that span the desired composition space using principal component analysis (PCA). The transport of principal components (PCs) can reduce the number of transported scalars and improve the spatial and temporal resolution requirements. The strategy is demonstrated using DNS of a premixed methane–air flame in a 2D vortical flow and is extended to the 3D geometry to demonstrate the resulting enhancement in the computational efficiency of PC transport. The PCs are derived from a priori PCA of the same composition space using DNS. This analysis is used to construct and tabulate the PCs’ chemical source terms in terms of the PCs using artificial neural networks (ANN). Comparison of DNS based on a full thermo-chemical state and DNS based on PC transport with six PCs shows excellent agreement even for terms that are not included in the PCA reduction. The transported PCs reproduce some of the salient features of strongly curved and strongly strained flames. The results also show a significant reduction of two orders of magnitude in the computational cost of the simulations, which enables an extension of the solution approach to 3D DNS under similar computational requirements. 相似文献