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301.
S. Aljančić 《Mathematische Zeitschrift》1963,81(3):215-222
Ohne Zusammenfassung 相似文献
302.
D. K.?SunkoEmail author S.?Bari?i? 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,46(2):269-279
We study the effect of antiferromagnetic (AF) correlations in the three-band
Emery model, with respect to the experimental situation in weakly underdoped
and optimally doped BSCCO. In the vicinity of the vH singularity of the
conduction band there appears a central peak in the middle of a pseudogap,
which is in an antiadiabatic regime, insensitive to the time scale of the
mechanism responsible for the pseudogap. We find a quantum low-temperature
regime corresponding to experiment, in which the pseudogap is created by
zero-point motion of the magnons, as opposed to the usual semiclassical
derivation, where it is due to a divergence of the magnon occupation number.
Detailed analysis of the spectral functions along the (π,0)–(π,π)
line show significant agreement with experiment, both qualitative and, in the
principal scales, quantitative. The observed slight approaching-then-receding
of both the wide and narrow peaks with respect to the Fermi energy is also
reproduced. We conclude that optimally doped BSCCO has a well-developed
pseudogap of the order of 1000 K. This is only masked by the narrow
antiadiabatic peak, which provides a small energy scale, unrelated to the AF
scale, and primarily controlled by the position of the chemical potential. 相似文献
303.
N. M.??i?ovi? G. Lj.?Majstorovi? N.?Konjevi?Email author 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,32(3):347-354
Results of a Doppler spectroscopy study of hydrogen and deuterium
Balmer lines in the stainless steel and copper hollow cathode glow
discharge, operated in pure hydrogen, deuterium and mixtures of inert gases
with hydrogen, are reported. For all gases and gas mixtures plasma
observations perpendicular to electric field revealed the excessively large
Doppler broadening. By changing mode of glow discharge operation, the
Doppler broadened line profiles in helium-hydrogen mixture are recorded
parallel to the discharge electric field as well. The excessively broadened
part of the H line profile is shifted towards blue or red
wavelength by changing the direction of electric field vector. The presence
of large excessive Balmer lines broadening in pure hydrogen and in its gas
mixture with neon as well as shifting of the excessively broadened part of
line profile by means of electric field is in contradiction with the
resonance transfer model proposed by Mills et al. in several publications,
see e.g. [IEEE Trans. Plasma Sci. 31, 338 (2003)]. 相似文献
304.
305.
The idea that spacetime has to be replaced by Clifford space (C-space) is explored. Quantum field theory (QFT) and string
theory are generalized to C-space. It is shown how one can solve the cosmological constant problem and formulate string theory
without central terms in the Virasoro algebra by exploiting the peculiar pseudo-Euclidean signature of C-space and the Jackiw
definition of the vacuum state. As an introduction into the subject, a toy model of the harmonic oscillator in pseudo-Euclidean
space is studied. 相似文献
306.
In dynamical systems theory, a standard method for passing from discrete time to continuous time is to construct the suspension
flow under a roof function. In this paper, we give conditions under which statistical laws, such as the central limit theorem
and almost sure invariance principle, for the underlying discrete time system are inherited by the suspension flow. As a consequence,
we give a simpler proof of the results of Ratner (1973) and recover the results of Denker and Philipp (1984) for Axiom A flows.
Morcover, we obtain several new results for nonuniformly and partially hyperbolic flows, including frame flows on negatively
curved manifolds satisfying a pinching condition. 相似文献
307.
Sa?a?NovakEmail author Susana?Maria?Henriques?Olhero José?Maria?Fonte?Ferreira Andreja?Zupan?i? 《Rheologica Acta》2004,43(5):559-566
Due to the hygroscopic nature of fine alumina powders, the presence of water may have a detrimental effect on the rheological properties of a suspension in melted paraffin for low-pressure injection moulding (LPIM). For this reason, a modification of the powder surface from hydrophilic to hydrophobic is essential for the production of high-quality moulded ceramics. In our paper, the efficiency of the application and the chemisorption of protective monomolecular layers of a long-chain carboxylic acid or its salts will be presented. The effect of the powder treatment on the shear viscosity and the viscoelastic properties of the suspensions for LPIM as well as on their stability in terms of the detrimental effect of water will be discussed.This paper was presented at the first Annual European Rheology Conference (AERC) held in Guimarães, Portugal, September 11-13, 2003. 相似文献
308.
M.?Miklav?i?Email author C. Y.?Wang 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,55(2):235-246
Von Kármáns problem of a rotating disk in an
infinite viscous fluid is extended to
the case where the disk surface admits partial slip. The nonlinear similarity equations
are integrated accurately for the full range of slip coefficients.
The effects of slip are discussed. An existence proof is also
given. 相似文献
309.
We consider a general class of models consisting of a small quantum system $S$ interacting with a reservoir $R$ . We compare three applications of 2nd order perturbation theory (the Fermi Golden Rule) to the study of such models: (1) the van Hove (weak coupling) limit for the dynamics reduced to $S$ ; (2) the Fermi Golden Rule applied to the Liouvillean—an argument that was used in recent papers on the return to equilibrium; (3) the Fermi Golden Rule applied to the so-called C-Liouvillean. These three applications lead to three Level Shift Operators. As our main result, we prove that if the reservoir $R$ is thermal (if it satisfies the KMS condition), then the Level Shift Operator obtained in (1) (often called the Davies generator) and the Level Shift Operator constructed in (2) are connected by a similarity transformation. We also show that the Davies generator coincides with the Level Shift Operator obtained in (3) for a general $R$ . 相似文献
310.
G. Duplančić P. Minkowski J. Trampetić 《The European Physical Journal C - Particles and Fields》2004,35(2):189-193
We calculate the absorption probability of photons radiated from the surface of the Sun by a left-handed neutrino with definite mass and a typical momentum for which we choose |p1| = 0.2 MeV, producing a heavier right-handed antineutrino. Considering the two transitions
and
we obtain the two oscillation lengths L12 = 4960.8 m, L23 = 198.4 m, the two absorption probabilities P12abs. = 2.5 x 10-67, P23abs. = 1.2 x 10-58 and the two absorption ranges
au,
au, using a neutrino mass differences of
meV,
meV and associated transition dipole moments. We collect all necessary theoretical ingredients, i.e. neutrino mass and mixing scheme, induced electromagnetic transition dipole moments, quadratic charged lepton mass asymmetries and their interdependence.Received: 4 November 2003, Revised: 23 March 2004, Published online: 5 May 2004 相似文献