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351.
C. Mœglin 《Advances in Mathematics》2011,228(2):1068
This paper is about the pole of some Eisenstein series for classical groups over a number field. In a previous paper, we have shown how to normalize intertwining operators in such a way that they are holomorphic for positive parameters. Here we show that the image of such operators is (in the interesting cases) either 0 or an irreducible representation. This enables us to compute explicitly the residue of the Eisenstein series obtained from square integrable cohomological representations. At the end of the paper we give necessary and sufficient conditions in terms of Arthur?s data in order that a square integrable cohomological representation is cuspidal; the conditions are not totally satisfactory and we explain what we expect when Arthur?s results will be fully available. 相似文献
352.
C.T. Fleaca I. Morjan F. Dumitrache L. Gavrila-Florescu A. Derory 《Applied Surface Science》2009,255(10):5386-5390
Two types of core-shell nanoparticles have been prepared by laser pyrolysis using Fe(CO)5 and C2H2 or [(CH3)3Si]2O as precursors and C2H4 as sensitizer. The first type (about 4 nm diameter) - produced by the decomposition of Fe(CO)5 in the presence of C2H4 and C2H2 - consists of Fe cores protected by graphenic layers. The second type (mean particle size of about 14 nm) consists also of Fe cores, yet covered by few nm thick γ-Fe2O3/porous polycarbosiloxane shells resulted from the [(CH3)3Si]2O decomposition and superficial oxidation after air exposure. The hysteresis loops suggest a room temperature superparamagnetic behavior of the Fe-C nanopowder and a weak ferromagnetic one for larger particles in the Fe-Fe2O3-polymer sample. Both types of nanoparticles were finally used as a catalyst for the carbon nanotube growth by seeding Si(100) substrates via drop-casting method. CNTs were grown by Hot-Filament Direct.Current PE CVD technique from C2H2 and H2 at 980 K. It is suggested that the increased density and orientation degree observed for the multiwall nanotubes grown from Fe-Fe2O3-polymer nanoparticles could be due to their magnetic behavior and surface composition. 相似文献
353.
D. PanX.G. Wan 《Physica B: Condensed Matter》2011,406(5):1129-1131
We investigate the electronic structure of EuPtSi3 using full potential linearized augmented plane wave method within the generalized gradient approximation. We reproduce the observed easy axis of magnetization as well as magnetic moment and propose that the magnetic configuration for this compound is incommensurate or noncollinear. We find that the spin configuration has only negligible effect on the band around Fermi energy. EuPtSi3 and its isostructural superconductor BaPtSi3 have similar band structures. Despite the shorter Pt-Si bond, EuPtSi3 possesses larger density of state near the Fermi energy compared with BaPtSi3, thus the structural difference and the associated difference in band structure cannot explain the non-superconductivity of EuPtSi3. 相似文献
354.
By successively taking into account various interactions for d2 ions in trigonally distorted cubic crystal fields, detailed analyses, derivations and calculations of the zero-field splitting (ZFS) and g factors of the ground state have been carried out; and their physical essentials and origins have been clearly revealed. The mistakes and shortcomings in some references have been corrected and improved. The calculated results are in excellent agreement with experimental data and much better than those of previous work. It is found that both the combined action of the trigonal field and spin-orbit interaction and the interaction between the ground state and excited states are quite necessary for causing ZFS of the ground state, and both the spin-orbit interaction and the admixture between the ground state and excited states are necessary for causing the deviation of g factors of the ground state from spin-only values. 相似文献
355.
Laser-induced desorption of metal atoms from the surface of small metal particles has been investigated as a function of the shape of the particles and the polarization of the incident laser light. The particles were supported on LiF, quartz or sapphire substrates. In a first set of experiments, the shape of the particles was determined by recording optical transmission spectra with s- and p-polarized light incident under an angle of typically 40° with respect to the surface normal. The metal particles turn out to be oblate, the ratio of the axes perpendicular and parallel to the substrate surface being on the order of 0.5. This ratio decreases with increasing particle size. Also, the particles change shape if the temperature is raised. In further experiments, s- and p-polarized light has been used to stimulate desorption of atoms via surface plasmon excitation. It is found that the desorption rate markedly depends on the polarization of the light. This is explained by excitation of the collective electron oscillation along different axes of the non-spherical particles. 相似文献
356.
M. Landolt 《Applied Physics A: Materials Science & Processing》1986,41(1):83-89
Observing the spin polarization of emitted electrons reveals surface magnetic information. In particular, high resolving power is achieved in different respects: 1) Magnetic micrography with a lateral resolution of 50 nm in a scanning electron microscope; 2) Non-destructive magnetic depth profiling in the 5–50 Å range with secondary electron emission; 3) Element specific chemical resolution using Auger electron emission; 4) Time-resolved magnetization measurements with pulsed-laser photoemission in less than 10 ns. The state-of-the-art of these techniques is illustrated with specific examples of surface magnetism. 相似文献
357.
The sensitivity of the lightest supersymmetric particle relic density calculation to the variation of the cosmological expansion rate before nucleosynthesis is discussed. Such a modification of the expansion rate, even extremely modest and with no consequence on the cosmological observations, can greatly enhance the calculated relic density, and therefore change the constraints on the SUSY parameter space drastically. We illustrate this variation in two examples of SUSY models, and show that it is unsafe to use the lower bound of the WMAP limits in order to constrain supersymmetry. We therefore suggest to use only the upper value ΩDMh2<0.135. 相似文献
358.
Taizo Kawauchi Katsuyuki Fukutani Shunji Kishimoto Yoshitaka Yoda 《Applied Surface Science》2009,256(4):962-964
Measurements of the internal-conversion electron emission due to the inelastic nuclear resonant excitation are reported. thin films of 20 and 1.3 nm thickness were deposited on Si(1 1 1), and the internal-conversion electrons were measured as a function of the photon energy. From the inelastic part of the spectra, the phonon density of states was obtained. Whereas the phonon density of states of 20-nm thick film resembles that of bulk -Fe, the 1.3-nm thick film revealed an obvious softening of the acoustic mode. 相似文献
359.
360.