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981.
Renato S. Gonnelli Mauro Tortello Dario Daghero Giovanni Alberto Ummarino Valeri A. Stepanov Jun S. Kim 《Central European Journal of Physics》2009,7(2):251-256
Point-contact Andreev-reflection (PCAR) experiments were performed in the Fe-1111 layered superconductor LaFeAsO0.9F0.1 with resistive T
c
on
∼ 27 K. The observation of two pairs of peaks in the low-temperature Andreev-reflection spectra clearly indicates the presence
of two order parameters. The behavior of the two gaps as a function of temperature, obtained by fitting the conductance curves
by means of the generalized two-band Blonder-Tinkham-Klapwijk model, shows some anomalies. A theoretical analysis performed
within the two-band Eliashberg theory with a generic electron-boson coupling can reproduce the low-temperature value of the
two gaps but generally fails in giving a satisfactory fit of their overall temperature dependence, indicating the rich and
complex physics of these newly discovered superconductors.
相似文献
982.
983.
In this paper, we give the overview on Faddeev-Jackiw method and its improved one, as well as the relative studies recently and realize quantization of the superconductive system by the two methods, we get the same results by the two disposal methods. Furthermore, at convenience of the familiar study in this system, we take it as the application example and compare the two methods by dealing with this system from different aspects, demonstrate the improved Faddeev-Jackiw method is effective and significative, and represent the superiorities of the improved Faddeev-Jackiw method. We show that the improved method may simplify investigations of different complicated constrained systems. 相似文献
984.
Statistical physics and information theory is applied to the clinical chemistry measurements present in a patient database containing 2.5 million patients' data over a 20-year period. Despite the seemingly naive approach of aggregating all patients over all times (with respect to particular clinical chemistry measurements), both a diurnal signal in the decay of the time-delayed mutual information and the presence of two sub-populations with differing health are detected. This provides a proof in principle that the highly fragmented data in electronic health records has potential for being useful in defining disease and human phenotypes. 相似文献
985.
We analyze systems of atomistic interactions on a triangular lattice allowing for fracture under a geometric condition on the triangles corresponding to a microscopic impenetrability constraint. Such systems can be thought as a computational simulation of materials undergoing brittle fracture. We show that in the small-deformation regime such approximation can be validated analytically in the framework of variational models of fracture. Conversely, in a finite-deformation regime various pathologies show that the continuum approximation of such a system differs from the usual variational representations of fracture and either needs new types of formulations on the continuum, or a proper interpretation of the atomistic constraints limiting their range and adapting them to a dynamical framework. 相似文献
986.
The thermodynamic properties of 135 polychlorinated phenothiazines (PCPTZs) in the standard state are calculated using a combination of quantum mechanical computations performed with the Gaussian 03 program at the B3LYP/6-311G** level, and their octanol-water partition coefficients (logKow) are calculated based on group contributions. The chlorine substitution pattern strongly influenced the thermodynamic properties and hydrophilicity of the compounds. The thermodynamic properties of congeners also depend on the chlorine substitution pattern. The effect of chlorine substitution pattern is quantitatively studied by considering the number and position of Cl atom substitution (NPCS). The results show that the NPCS model may be used to predict the thermodynamic properties and hydrophilicity for all 135 PCPTZ congeners. 相似文献
987.
Yong-Long Wang 《International Journal of Theoretical Physics》2009,48(5):1422-1430
In the framework of Faddeev-Senjanovic (FS) path-integral quantization, CP
1 nonlinear σ model coupled to Non-Abelian Chern-Simons (CS) fields is quantized. Generalized canonical Ward identities (WI) are deduced
from the invariance of the canonical effective action under gauge transformations, which are obtained from the generators
of gauge transformations, including all first-class constraints, in Dirac’s sense. The generalized canonical WI has brief
form and is equivalent to canonical WI under gauge transformations in Dirac’s sense.
This project is supported by Foundation of National Natural Science (10671086), Foundation of Shandong Natural Science (Y2007A01)
and National Laboratory for Superlattices and Microstructures (CHJG200605). 相似文献
988.
In the spirit of the Hamiltonian QR algorithm and other bidirectional chasing algorithms, a structure-preserving variant of
the implicit QR algorithm for palindromic eigenvalue problems is proposed. This new palindromic QR algorithm is strongly backward
stable and requires less operations than the standard QZ algorithm, but is restricted to matrix classes where a preliminary
reduction to structured Hessenberg form can be performed. By an extension of the implicit Q theorem, the palindromic QR algorithm
is shown to be equivalent to a previously developed explicit version. Also, the classical convergence theory for the QR algorithm
can be extended to prove local quadratic convergence. We briefly demonstrate how even eigenvalue problems can be addressed
by similar techniques.
D. S. Watkins partly supported by Deutsche Forschungsgemeinschaft through Matheon, the DFG Research Center Mathematics for key technologies in Berlin. 相似文献
989.
Roumen Tsekov 《International Journal of Theoretical Physics》2009,48(9):2660-2664
The simplest density functional theory due to Thomas, Fermi, Dirac and Weizsäcker is employed to describe the non-equilibrium thermodynamic evolution of an electron gas. The temperature effect is introduced via the Fermi-Dirac entropy, while the irreversible dynamics is described by a non-linear diffusion equation. A dissipative Kohn-Sham equation is also proposed, which improves the Thomas-Fermi-Weizsäcker kinetic functional. 相似文献
990.
L. Vadkhiya M.K. Bhayani B.L. Ahuja 《Journal of magnetism and magnetic materials》2010,322(19):2857-2867
We have computed spin-dependent energy bands, spin moments and density of states of NiAs-type CrX (X=S, Se and Te) chalcogenides using linear combination of atomic orbitals method within density functional theory as well as full potential augmented plane wave method. In addition, magnetic properties have also been computed using spin polarized relativistic Korringa-Kohn-Rostoker method. We have also obtained the first ever theoretical electron momentum densities of CrX compounds considering linear combination of atomic orbitals and compared the results with the isotropic Compton profiles measured using 20 Ci 137Cs Compton spectrometer. The Fermi surface topology and magnetic properties are discussed in terms of majority and minority energy bands and density of states. In addition, to highlight the role of Cr (3d) electrons in such type of chalcogenides, we have also reported the magnetic Compton profile of CrTe using the Korringa-Kohn-Rostoker method. 相似文献