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971.
For disjoint subsets of the Michael space has the topology obtained by isolating the points in and letting the points in retain the neighborhoods inherited from . We study normality of the product of Michael spaces with complete metric spaces. There is a ZFC example of a Lindelöf Michael space , of minimal weight , with Lindelöf but with not normal. ( denotes the countable product of a discrete space of cardinality .) If denotes , the normality of implies the normality of for any complete metric space (of arbitrary weight). However, the statement `` normal implies normal' is axiom sensitive.
972.
V. G. Puzarenko 《Algebra and Logic》2004,43(6):418-423
We deal with the problem asking whether hereditarily finite superstructures have elementary extensions of the form
. In so doing, we settle the question whether a theory for some hereditarily finite superstructure have
models of arbitrarily large cardinality. A Hanf number is shown to exist, and we provide an exact bound for the countable case. 相似文献
973.
J. M. A. M. van Neerven 《Proceedings of the American Mathematical Society》2002,130(8):2325-2333
Let be a -semigroup with generator on a Banach space . Let be a fixed element. We prove the following individual stability results.
(i) Suppose is an ordered Banach space with weakly normal closed cone and assume there exists such that for all . If the local resolvent admits a bounded analytic extension to the right half-plane 0\}$">, then for all and we have
(ii) Suppose is a rearrangement invariant Banach function space over with order continuous norm. If is an element such that defines an element of , then for all and we have
974.
In this paper normal liquid helium-3 is studied for the first time within the framework of the so-called static fluctuation approximation. This is based on the replacement of the square of the local-field operator with its mean value. A closed set of nonlinear integral equations is derived for neutral many-fermionic systems. This set is solved numerically by an iteration method for a realistic interhelium potential. The thermodynamic properties are then obtained for normal liquid helium-3. The quadratic-fluctuation approximation is found to be valid for this system in the low-temperature limit (0.25 K). Our results are presented in a set of figures. The role of the interaction is emphasized, and the functional dependence on the temperature of key thermodynamic quantities is derived for normal liquid helium-3. 相似文献
975.
Radulescu O. Janssen T. Etrillard J. 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(3):385-398
We compare within an unifying formalism the dynamical properties of modulated and composite aperiodic (incommensurate) crystals.
We discuss the concept of inner polarization and we define an inner polarization parameter β that distinguishes between different
acoustic modes of aperiodic crystals. Although this concept has its limitations, we show that it can be used to extract valuable
information from neutron coherent inelastic scattering experiments. Within certain conditions, the ratio between the dynamic
and the static structure factors at various Bragg peaks depends only on β. We show how the knowledge of β for modes of an
unknown structure can be used to decide whether the structure is composite or modulated. The same information can be used
to predict scattered intensity within unexplored regions of the reciprocal space, being thus a guide for experiments.
Received 9 June 2002 Published online 14 October 2002
RID="a"
ID="a"e-mail: Ovidiu.Radulescu@univ-rennes1.fr 相似文献
976.
E. Cappelluti C. Grimaldi L. Pietronero 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(4):511-517
In small Fermi energy metals, disorder can deeply modify superconducting state properties leading to a strong suppression
of the critical temperature Tc. In this paper, we show that also normal state properties can be seriously influenced by disorder when the Fermi energy E
F is sufficiently small. We calculate the normal state spin susceptibility χ for a narrow band electron-phonon coupled metal
as a function of the non-magnetic impurity scattering rate . We find that as soon as is comparable to E
F, χ is strongly reduced with respect to its value in the clean limit. The effects of the electron-phonon interaction including
the nonadiabatic corrections are discussed. Our results strongly suggest that the recent finding on irradiated MgB2 samples can be naturally explained in terms of small E
F values associated with the σ-bands of the boron plane, sustaining therefore the hypothesis that MgB2 is a nonadiabatic metal.
Received 31 July 2002 / Received in final form 21 September 2002 Published online 31 December 2002 相似文献
977.
Phillip Griffith 《Transactions of the American Mathematical Society》2001,353(1):77-93
The main result states: if is a module finite extension of excellent local normal domains which is unramified in codimension two and if represents a deformation of the completion of , then there is a corresponding -algebra deformation such that the ring homomorphism represents a deformation of . The main application is to the ascent of the arithmetic Cohen-Macaulay property for an étale map of smooth projective varieties over an algebraically closed field. 相似文献
978.
Maik Nowak 《Rheologica Acta》2001,40(4):366-372
The first normal stress differences N
1 of a highly dilute cationic surfactant solution are investigated in a cone-and-plate rheometer. In continuation of a previous
paper (Nowak 1998), where the buildup of a shear induced structure in such a solution was attained after a reduced deformation,
the N
1 turned out to be in proportion to the square of the shear rate γ˙ reduced by a critical value γ˙
c
in a first range above γ˙
c
. At higher shear rates the N
1 tend to lower values than predicted by this relation.
Relaxation experiments were performed in the same geometry to determine the characteristic time scales of the shear induced
state's decay. In the lower range above &γdot;
c
the stress decay is a monoexponential process, while a second time constant has to be introduced to describe the relaxation
in that range, where the N
1 deviate from the parabolic dependence of the reduced shear rate.
Received: 10 May 1999 Accepted: 15 November 2000 相似文献
979.
980.
This paper is concerned with an homogeneous isotropic linear elastic strip, in plane strain. It is supposed that its lateral
boundaries are displacement-free and that the deformation is generated by actions on the ends. A cross-sectional measure of
deformation, complementing that of a previous paper, is defined and shown to satisfy a generalised convexity condition in
the axial variable x
1, for materials with negative Poisson's ratio σ. An enhanced measure is subsequently defined, and, in the case of a semi-infinite
strip, is shown to yield pointwise exponential decay estimates for both the axial and the transverse displacement components
for materials with positive Poisson's ratio.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献