9,839 research outputs found

    Earthquake source parameters of the 2009 Mw 7.8 Fiordland (New Zealand) earthquake from L-band InSAR observations

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    The 2009 MW7.8 Fiordland (New Zealand) earthquake is the largest to have occurred in New Zealand since the 1931 Mw 7.8 Hawke’s Bay earthquake, 1 000 km to the northwest. In this paper two tracks of ALOS PALSAR interferograms (one ascending and one descending) are used to determine fault geometry and slip distribution of this large earthquake. Modeling the event as dislocation in an elastic half-space suggests that the earthquake resulted from slip on a SSW-NNE orientated thrust fault that is associated with the subduction between the Pacific and Australian Plates, with oblique displacement of up to 6.3 m. This finding is consistent with the preliminary studies undertaken by the USGS using seismic data

    Do Anionic Titanium Dioxide Nano-Clusters Reach Bulk Band Gap? A Density Functional Theory Study

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    The electronic properties of both neutral and anionic (TiO2)n (n = 1-10) clusters are investigated by extensive density functional theory calculations. The predicted electron detachment energies and excitation gaps of anionic clusters agree well with the original experimental anion photoelectron spectra (APES). It is shown that the old way to analyze APES tends to overestimate vertical excitation gaps (VGA) of large anionic clusters, due to the nature of multiple electronic origins for the higher APES bands. Moreover, the VGA of anionic TiO2 clusters are evidently smaller than those of neutral clusters, which may also be the case for other metal oxide clusters with high electron affinity

    A refined invariant subspace method and applications to evolution equations

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    The invariant subspace method is refined to present more unity and more diversity of exact solutions to evolution equations. The key idea is to take subspaces of solutions to linear ordinary differential equations as invariant subspaces that evolution equations admit. A two-component nonlinear system of dissipative equations was analyzed to shed light on the resulting theory, and two concrete examples are given to find invariant subspaces associated with 2nd-order and 3rd-order linear ordinary differential equations and their corresponding exact solutions with generalized separated variables.Comment: 16 page

    Fe-doping induced superconductivity in charge-density-wave system 1T-TaS2

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    We report the interplay between charge-density-wave (CDW) and superconductivity of 1TT-Fex_{x}Ta1−x_{1-x}S2_{2} (0≤x≤0.050\leq x \leq 0.05) single crystals. The CDW order is gradually suppressed by Fe-doping, accompanied by the disappearance of pseudogap/Mott-gap as shown by the density functional theory (DFT) calculations. The superconducting state develops at low temperatures within the CDW state for the samples with the moderate doping levels. The superconductivity strongly depends on xx within a narrow range, and the maximum superconducting transition temperature is 2.8 K as x=0.02x=0.02. We propose that the induced superconductivity and CDW phases are separated in real space. For high doping level (x>0.04x>0.04), the Anderson localization (AL) state appears, resulting in a large increase of resistivity. We present a complete electronic phase diagram of 1TT-Fex_{x}Ta1−x_{1-x}S2_{2} system that shows a dome-like Tc(x)T_{c}(x)

    On the Integrability, B\"Acklund Transformation and Symmetry Aspects of a Generalized Fisher Type Nonlinear Reaction-Diffusion Equation

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    The dynamics of nonlinear reaction-diffusion systems is dominated by the onset of patterns and Fisher equation is considered to be a prototype of such diffusive equations. Here we investigate the integrability properties of a generalized Fisher equation in both (1+1) and (2+1) dimensions. A Painlev\'e singularity structure analysis singles out a special case (m=2m=2) as integrable. More interestingly, a B\"acklund transformation is shown to give rise to a linearizing transformation for the integrable case. A Lie symmetry analysis again separates out the same m=2m=2 case as the integrable one and hence we report several physically interesting solutions via similarity reductions. Thus we give a group theoretical interpretation for the system under study. Explicit and numerical solutions for specific cases of nonintegrable systems are also given. In particular, the system is found to exhibit different types of travelling wave solutions and patterns, static structures and localized structures. Besides the Lie symmetry analysis, nonclassical and generalized conditional symmetry analysis are also carried out.Comment: 30 pages, 10 figures, to appear in Int. J. Bifur. Chaos (2004

    Exploring Renner-Teller Induced Quenching in the Reaction H(\u3csup\u3e2\u3c/sup\u3e\u3ci\u3eS\u3c/i\u3e)+NH(\u3ci\u3ea\u3c/i\u3e\u3csup\u3e1\u3c/sup\u3eΔ): A Combined Experimental and Theoretical Study

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    Experimental rate coefficients for the removal of NH(a1Δ) and ND(a1Δ) in collisions with H and D atoms are presented; all four isotope combinations are considered: NH+H, NH+D, ND+H, and ND+D. The experiments were performed in a quasistatic laser-flash photolysis/laser-induced fluorescence system at low pressures. NH(a1Δ) and ND(a1Δ) were generated by photolysis of HN3 and DN3, respectively. The total removal rate coefficients at room temperature are in the range of (3-5) x 1013 cm3 mol-1 s-1. For two isotope combinations, NH+H and NH+D, quenching rate coefficients for the production of NH(X 3Σ-) or ND(X 3Σ-) were also determined; they are in the range of 1x1013 cm3 mol-1 s-1. The quenching rate coefficients directly reflect the strength of the Renner-Teller coupling between the 2A and 2A\u27 electronic states near linearity and so can be used to test theoretical models for describing this nonadiabatic process. The title reaction was modeled with a simple surface-hopping approach including a single parameter, which was adjusted to reproduce the quenching rate for NH+H; the same parameter value was used for all isotope combinations. The agreement with the measured total removal rate is good for all but one isotope combination. However, the quenching rates for the NH+D combination are only in fair (factor of 2) agreement with the corresponding data

    Mass movement susceptibility mapping using satellite optical imagery compared with InSAR monitoring: Zigui County, Three Gorges region, China

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    Mass movements on steep slopes are a major hazard to communities and infrastructure in the Three Gorges region, China. Developing susceptibility maps of mass movements is therefore very important in both current and future land use planning. This study employed satellite optical imagery and an ASTER GDEM (15 m) to derive various parameters (namely geology; slope gradient; proximity to drainage networks and proximity to lineaments) in order to create a GIS-based map of mass movement susceptibility. This map was then evaluated using highly accurate deformation signals processed using the Persistent Scatterer (PS) InSAR technique. Areas of high susceptibility correspond well to points of high subsidence, which provides a strong support of our susceptibility map
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