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61.
A. Šimůnek J. Vackář K. Kunc J. Hutter 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(2):245-249
A soft, norm-conserving pseudopotential for carbon is presented and its performance tested by calculations on atomic states
and on diamond: electronic energy levels of different atomic configurations, equilibrium lattice constant, bulk modulus, and
the TA(X) frozen-phonon frequency are accurately reproduced. Convergence of the total energy of diamond with the size of the
plane-wave basis set is compared for several frequently used pseudopotentials, and it is shown that calculations with the
reported pseudopotential can be performed at considerably lower cost than with the other norm-conserving pseudopotentials,
without loosing the accuracy of the latter in predicting structural and dynamical properties. The rapid convergence of the
results with the plane-wave cutoff is comparable to the performance of the Vanderbilt's ultrasoft pseudopotentials. The transferability
of the pseudopotential to other electronic configurations is discussed.
Received 8 September 1999 相似文献
62.
Jeroen Schillewaert 《Designs, Codes and Cryptography》2008,47(1-3):165-175
This work is inspired by a paper of Hertel and Pott on maximum non-linear functions (Hertel and Pott, A characterization of
a class of maximum non-linear functions. Preprint, 2006). Geometrically, these functions correspond with quasi-quadrics; objects
introduced in De Clerck et al. (Australas J Combin 22:151–166, 2000). Hertel and Pott obtain a characterization of some binary
quasi-quadrics in affine spaces by their intersection numbers with hyperplanes and spaces of codimension 2. We obtain a similar
characterization for quadrics in projective spaces by intersection numbers with low-dimensional spaces. Ferri and Tallini
(Rend Mat Appl 11(1): 15–21, 1991) characterized the non-singular quadric Q(4,q) by its intersection numbers with planes and solids. We prove a corollary of this theorem for Q(4,q) and then extend this corollary to all quadrics in PG(n,q),n ≥ 4. The only exceptions occur for q even, where we can have an oval or an ovoid as intersection with our point set in the non-singular part.
相似文献
63.
64.
D. Meyer W. Nolting 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(3):385-395
We compare different approximation schemes for investigating ferromagnetism in the periodic Anderson model. The use of several
approximations allows for a detailed analysis of the implications of the respective methods, and also of the mechanisms driving
the ferromagnetic transition. For the Kondo limit, our results confirm a previously proposed mechanism leading to ferromagnetic
order, namely an RKKY exchange mediated via the formation of Kondo screening clouds in the conduction band. The contrary case is found in the intermediate-valence regime.
Here, the bandshift correction ensuring a correct high-energy expansion of the self-energy is essential. Inclusion of damping
effects reduces stability of the ferromagnetic phase.
Received 5 June 2000 and Received in final form 3 August 2000 相似文献
65.
M. Manekar S. B. Roy 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(1):19-25
We investigate the electronic structure of
Sr2FeMoO6/SrTiO3 (SFMO/STO) multilayers using the
ab initio Full Potential Linearized Augmented Plane Wave
method in order to study their properties within the GGA and GGA+U methods. We examin more especially the role of the interface
on the magnetic and transport properties of these multilayers taking into account a possible Fe deficiency at the interface
and we show that bulk behaviour is rapidly recovered due to the strong localization of
the interfacial perturbation. For perfect interfaces, the whole structure is found half-metallic within the GGA+U method;
the situation
being ambiguous within the GGA method where SFMO is at the limit of being half-metallic depending on the structural deformation
induced by the STO layer. This leads us to the conclusion that such a system could be used as injection electrode and tunnel
barrier in magnetic tunnel junctions with a fully spin polarized injected current.
For Fe deficient interfaces, we show that the interfacial densities of states are nearly unpolarized showing that this kind
of
imperfection has potentially a strong impact on the properties
of the multilayers. 相似文献
66.
67.
Anna Bosi 《Meccanica》2007,42(5):477-485
A wavelet-based methodology for detecting critical events in displacement and temperature histories, obtained by monitoring
in-situ thermoelastic structures, is proposed. It is based on the wavelet analysis of thermoelastic potentials furnishing
also the possibility to detect separately cases in which sudden jumps occur in the displacement history from those in which
they occur on temperature history. 相似文献
68.
K. K. Mishra S. Nagabhusan Achary Sharat Chandra T. R. Ravindran K. K. Pandey Avesh K. Tyagi Surinder M. Sharma 《ChemInform》2016,47(13):no-no
The title compound is synthesized by solid state reaction of a stoichiometric mixture of BaCO3 and TeO2 (air, 550 °C for 6 h, and 650 °C for 12 h). 相似文献
69.
Polycrystalline K2.5Bi2.5Ti4O13 (I) is prepared by solid state reaction of KNO3, Bi2O3, and TiO2 (Al2O3 crucible, 750 °C, 16 h). 相似文献
70.
Polycrystalline Li2SiP2 (I) and LiSi2P3 (II) are prepared by solid state reaction of stoichiometric amounts of the elements at 1123 K and 1223 K (II), resp. 相似文献