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Yan Z.,CAS Academy of Mathematics and Systems Science | Yan Z.,CAS International Center for Materials Physics | Konotop V.V.,University of Lisbon | Akhmediev N.,Australian National University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

Using symmetry analysis we systematically present a higher-dimensional similarity transformation reducing the (3+1) -dimensional inhomogeneous nonlinear Schrödinger (NLS) equation with variable coefficients and parabolic potential to the (1+1) -dimensional NLS equation with constant coefficients. This transformation allows us to relate certain class of localized exact solutions of the (3+1) -dimensional case to the variety of solutions of integrable NLS equation of the (1+1) -dimensional case. As an example, we illustrated our technique using two lowest-order rational solutions of the NLS equation as seeding functions to obtain rogue wavelike solutions localized in three dimensions that have complicated evolution in time including interactions between two time-dependent rogue wave solutions. The obtained three-dimensional rogue wavelike solutions may raise the possibility of relative experiments and potential applications in nonlinear optics and Bose-Einstein condensates. © 2010 The American Physical Society.

Yan Z.,University of Lisbon | Yan Z.,Institute of Systems Science | Yan Z.,CAS International Center for Materials Physics
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010

The analytical nonautonomous rogons are reported for the inhomogeneous nonlinear Schrödinger equation with variable coefficients in terms of rational-like functions by using the similarity transformation and direct ansatz. These obtained solutions can be used to describe the possible formation mechanisms for optical, oceanic, and matter rogue wave phenomenon in optical fibres, the deep ocean, and Bose-Einstein condensates, respectively. Moreover, the snake propagation traces and the fascinating interactions of two nonautonomous rogons are generated for the chosen different parameters. The obtained nonautonomous rogons may excite the possibility of relative experiments and potential applications for the rogue wave phenomenon in the field of nonlinear science. © 2009 Elsevier B.V. All rights reserved.

Feng W.-L.,Chongqing University of Technology | Feng W.-L.,CAS International Center for Materials Physics
Materials Letters | Year: 2013

Eu2+, Eu2+ and Gd3+ co-doped SrAl 2O4 phosphors are synthesized by solid-state reaction method. Their structure, composition and luminescent properties are investigated by utilizing X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) analysis and photoluminescence spectra. The result shows that introduction of Eu2+ and Gd3+ does not change the crystal structure. The average crystallite sizes of phosphors are, 46.1 nm for SrAl2O 4: Eu2+ and 40.4 nm for SrAl2O4: Eu2+, Gd3+. The XPS results indicate all peaks of these elements are consistent with standard corresponding central values of those intensity peaks. The phosphor can be excited by broadband ultraviolet and partial visible light (300-480 nm) effectively and emits green or blue light that is related to the characteristic emission of Eu2+ due to 4f 65d1-4f7 transitions. The optimal doping concentrations of phosphors SrAl2O4: Eu2+, Eu2+ and Gd3+ are 3.5 mol%, 3.5 mol% and 12 mol%, respectively. © 2013 Elsevier B.V.

Feng W.L.,Chongqing University of Technology | Feng W.L.,CAS International Center for Materials Physics
Philosophical Magazine Letters | Year: 2010

The optical spectrum and electron paramagnetic resonance (EPR) parameters (gyromagnetic g factor and hyperfine structure constant A) for CdTe:V 3+ have been calculated using the modified crystal-field theory. In this theory, the covalency factors Nt, Ne and the two spin-orbit (SO) coupling coefficients ζd, ζp are included in Td symmetry. The calculated optical spectrum and EPR parameters agree reasonably well with the experimental values. In addition, the calculated results show that the contribution from the ligand Te2- to the EPR parameters cannot be neglected because the ligand Te2- possesses a large SO coupling coefficient and strong covalency. © 2010 Taylor & Francis.

Huang Y.,University of Electronic Science and Technology of China | Yan Y.,University of Electronic Science and Technology of China | Pang X.,University of Electronic Science and Technology of China | Pang X.,CAS International Center for Materials Physics
Ceramics International | Year: 2013

A novel method of electrolytic fluorine-doped hydroxyapatite/ZrO 2 double-layer coating was conducted on medical titanium in ZrO(NO 3) 2 aqueous solution and subsequently in the mixed solution of Ca(NO 3) 2, NH 4H 2PO 4 and NaF. The microstructure, phase composition, bond strength, dissolution rate and corrosion resistance of the films were studied. Results revealed that the additions of F - reduced the crystallite and increased the crystallinity of hydroxyapatite, structure of apatite was changed from micro-petal-like crystals to nano-needle-like crystals, which aligned vertically to the substrate. The approximately 10 μm thick layers was much denser and uniform. Addition of ZrO 2 buffer layer could improve the bond strength between the fluorine-doped hydroxyapatite layer and the substrate. The bond strength of the double-layer coating was found to be significantly higher than that of pure hydroxyapatite coating even after soaking in normal saline for two weeks. In physiological solution, the double-layer coating showed lower dissolution rate and stronger corrosion resistance than pure hydroxyapatite coating. © 2012 Elsevier Ltd and Techna Group S.r.l.

Wang H.-Q.,University of Sichuan | Kuang X.-Y.,University of Sichuan | Kuang X.-Y.,CAS International Center for Materials Physics | Li H.-F.,University of Sichuan
Physical Chemistry Chemical Physics | Year: 2010

The geometrical structures, relative stabilities, and electronic properties of small bare gold clusters Auλn and bimetallic complexes of bare metal clusters with one copper atom Aun-1Cuλ (charge λ = 0, +1, -1; 2 ≤ n ≤ 9) have been systematically investigated by means of first-principles density functional calculations at the B3LYP level. The results show that the most stable isomers have a planar structure and resemble pure gold clusters in shape, and no three-dimensional isomers were obtained for neutral and anionic doped gold clusters. However, the geometries of Aun-1Cu+ are found to undergo a structural change from two dimensional to three dimensional when the cluster contains 7 atoms. The calculated dissociation energy and second difference energy as a function of the cluster size exhibit a pronounced even-odd alternation phenomenon. Ionization potentials and electron detachment energies (both vertical and adiabatic) of Auλnand Aun-1Cuλ clusters are discussed and compared with available experimental results. A good agreement between experimental and theoretical results suggests good prediction of the lowest energy structures for all clusters calculated in the present study. © 2010 The Owner Societies.

Gao G.Y.,Huazhong University of Science and Technology | Yao K.L.,Huazhong University of Science and Technology | Yao K.L.,CAS International Center for Materials Physics | Li N.,Huazhong University of Science and Technology
Journal of Physics Condensed Matter | Year: 2011

Recent theoretical studies indicate that metastable rocksalt CaN, SrN, and BaN exhibit half-metallic ferromagnetism (Volnianska and Boguslawski 2007 Phys. Rev. B 75 224418; Gao et al 2008 Phys. Lett. A 372 1512), and further experiments confirm the existence of self-assembled metastable CaN nanostructures (Liu et al 2008 Surf. Sci. 602 1844). We here use the first-principles method based on density functional theory to investigate the structural, electronic, and magnetic properties of the (111) surfaces of CaN and SrN and the interfaces of CaN/InN(111) and SrN/GaP(111). The surface stability from the calculated surface energy indicates that the N-terminated (111) surface is more stable than the Ca (Sr)-terminated (111) surface in the N-rich environment. For CaN and SrN, both anion- and cation-terminated (111) surfaces preserve the half-metallic characteristics of the bulk. Interfacial studies indicate that the half-metallicity of bulk CaN is retained in two of the four possible configurations of the CaN/InN(111) interface, while for the interface of SrN/GaP(111) only one interfacial configuration shows half-metallicity. Furthermore, we assess the interfacial adhesive strength for all the possible different configurations of the interfaces studied here by calculating the interface adhesion energies. © 2011 IOP Publishing Ltd.

Zhou K.,CAS International Center for Materials Physics | Zhang Z.,CAS International Center for Materials Physics
Physical Review Letters | Year: 2012

We investigate the effects of Rashba-type spin-orbit coupling (SOC) on the condensed density and superfluid density tensor of a two-component Fermi gas in the BCS-BEC crossover at zero temperature. In anisotropic three dimensions (3D), we find that SOC has an opposite effect on condensation (enhanced) and superfluidity (suppressed in the SOC direction), and this effect becomes most pronounced for very weak interactions and the SOC strength being larger than a characteristic value. Furthermore, as functions of SOC strength, the condensed density changes monotonically for all interaction parameters, while the superfluid density has a minimum when the interaction parameter is below a critical value. We also discuss the isotropic two-dimensional case where analytical expressions for the gap and number equations are obtained and the same phenomena are found as that of the 3D case. © 2012 American Physical Society.

Zhou K.,CAS International Center for Materials Physics | Liang Z.,CAS International Center for Materials Physics | Zhang Z.,CAS International Center for Materials Physics
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

We investigate the quantum phases of a dipolar Bose-Einstein condensate (BEC) in an optical lattice based on the extended Bose-Hubbard model taking into account the three-body scattering. Accordingly, the phase diagrams from the superfluid state to the Mott-insulator state for such BEC systems are obtained and analyzed, employing both the mean-field approach and the functional-integral method. In particular, we explore the combined effects of three-body interaction and dipole-dipole interaction on the insulating lobes in detail. The experimental scenario is also discussed. © 2010 The American Physical Society.

Ren W.-J.,CAS International Center for Materials Physics | Zhang Z.-D.,CAS International Center for Materials Physics
Chinese Physics B | Year: 2013

Studies of bulk MgCu2-type rare-earth iron compounds with Laves phase are reviewed. The relationship between magnetostriction and structural distortion and the consequent crystallographic method for measuring magnetostriction are introduced at first. Then we review recent progress in understanding bulk magnetostrictive Laves phase materials, especially the magnetostriction and the minimization of the anisotropy of the light rare-earth Pr- and Sm-based compounds. Finally, a summary and outlook for this kind of compounds are presented. © 2013 Chinese Physical Society and IOP Publishing Ltd.

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