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161.
Let X be a Banach space with a weak uniform normal structure and C a non–empty convexweakly compact subset of X. Under some suitable restriction, we prove that every asymptoticallyregular semigroup T = {T(t) : t ∈¸ S} of selfmappings on C satisfying
has a common fixed point, where WCS(X) is the weakly convergent sequence coefficient of X, and\({\left| {{\left\| {T(t)} \right\|}} \right|}\) is the exact Lipschitz constant of T(t). 相似文献
${\mathop {\lim \inf }\limits_{S \mathrel\backepsilon t \to \infty } }{\left| {{\left\| {T(t)} \right\|}} \right|} < {\text{WCS}}(X)$
162.
M. Samsel-Czekała G. Kontrym-Sznajd G. Döring W. Schülke J. Kwiatkowska F. Maniawski S. Kaprzyk A. Bansil 《Applied Physics A: Materials Science & Processing》2003,77(1):87-92
A reconstruction technique based on the solution of the Radon transform in terms of Jacobi polynomials is used to obtain the
3D electron momentum density, ϱ(p), from nine high-resolution Compton profiles (CPs) for a Cu0.9Al0.1 disordered alloy single crystal. The method was also applied to theoretical CPs computed within the Korringa–Kohn–Rostoker
coherent potential approximation (KKR-CPA) first-principles scheme for the same nine orientations of the crystal. The experimental
ϱ(p) is in satisfactory agreement with the theoretical ϱ(p), shows most details of the Fermi surface (FS) and exhibits electron correlation effects. We comment on the map of the FS
obtained by folding the reconstructed ϱ(p) into the first Brillouin zone, which yields the occupation number density, ϱ(k). A test of the validity of data via a consistency condition (within our reconstruction algorithm) as well as the propagation
of experimental noise in the reconstruction of both ϱ(p) and ϱ(k) are investigated.
Received: 24 October 2001 / Accepted: 20 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +48-71/344-10-29, E-mail: samsel@int.pan.wroc.pl 相似文献
163.
164.
Song-bai Sheng 《计算数学(英文版)》2001,(6)
1. IntroductionConsider the following nonsmooth equationsF(x) = 0 (l)where F: R" - R" is LipsChitz continuous. A lot of work has been done and is bellg doneto deal with (1). It is basicly a genera1ization of the cIassic Newton method [8,10,11,14],Newton-lthe methods[1,18] and quasiNewton methods [6,7]. As it is discussed in [7], the latter,quasiNewton methods, seem to be lindted when aPplied to nonsmooth caJse in that a boundof the deterioration of uPdating matrir can not be maintained w… 相似文献
165.
Weak L
2
-solutions u of the Schrödinger equation, –u + q(x) u – u = f(x) in L
2
, are represented by a Fourier series using spherical harmonics in order to prove the following strong maximum and anti-maximum principles in
(N 2): Let 1 denote the positive eigenfunction associated with the principal eigenvalue 1 of the Schrödinger operator
. Assume that the potential q(x) is radially symmetric and grows fast enough near infinity, and f is a `sufficiently smooth' perturbation of a radially symmetric function, f 0 and 0 f / C const a.e. in
. Then u is 1-positive for - < < 1 (i.e., u c 1 with c const > 0) and 1-negative for 1 < < 1 + (i.e., u –c1 with c const > 0), where > 0 is a number depending on f. The constant c > 0 depends on both and f. 相似文献
166.
The electron-phonon interaction in the periodic Anderson model (PAM) is considered. The PAM incorporates the effect of onsite
Coulomb interaction (U) between f-electrons. The influence of Coulomb correlation U on the phonon response of the system is studied by evaluating the phonon spectral function for various parameters of the
model. The numerical evaluation of the spectral function is carried out in the long wavelength limit at finite temperatures
keeping only linear terms in U. The observed behaviour is found to agree well with the general features obtained experimentally for some heavy fermion (HF)
systems. 相似文献
167.
H. B. Zhu H. X. Ge L. Y. Dong S. Q. Dai 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(1):103-108
Based on the Nagel-Schreckenberg (NaSch)
model of traffic flow, a modified cellular automaton (CA) traffic
model with the density-dependent randomization (abbreviated as the
DDR model) is proposed to simulate traffic flow. The fundamental
diagram obtained by simulation shows the ability of this modified
NaSch model to capture the essential features of traffic flow,
e.g., synchronized flow, metastable state, hysteresis and phase
separation at higher densities. Comparisons are made between this
DDR model and the NaSch model, also between this DDR model and the
VDR model. And the underlying mechanism is analyzed. All these
results indicate that the presented model is reasonable and more
realistic. 相似文献
168.
X. M. Chen J. X. Shao Z. H. Yang H. Q. Zhang Y. Cui X. Xu G. Q. Xiao Y. T. Zhao X. A. Zhang Y. P. Zhang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):281-286
Al K-shell X-ray yields are measured with highly charged Arq+ ions
(q=12–16) bombarding against aluminium. The energy range of the Ar
ions is from 180 to 380 keV. K-shell ionization cross sections of aluminium are also obtained from the yields data.
The experimental data is explained within the framework of 2pπ
-2pσ rotational coupling. When Ar ions with 2p-shell vacancies are
incident on aluminium, the vacancies begin to reduce. Meanwhile, collisions
against Al atoms lead to the production of new 2p-shell vacancies of Ar
ions. These Ar 2p-shell vacancies will transfer to the 1s orbit of an Al
atom via 2pπ-2pσ rotational coupling leading to the emission of
a K-shell X-ray of aluminiun. A model is constructed based on the base of
the above physical scenario. The calculation results of the model are in
agreement with the experimental results. 相似文献
169.
We present what we believe to be the first morphological evidence for the occurrence of surface pre-melting on the Si(1 1 1) surface. Our results complement the extensive previous evidence from diffraction and ion scattering techniques for the presence of pre-melted (liquid-like) layers on Si(1 1 1) below the bulk melting temperature and also suggest how atomic steps are involved in the initiation of such layers. Our results are based on atomic force microscopy studies of morphologies that are preserved when surfaces are annealed in a range of high temperatures and then rapidly cooled to room temperature for observation. A unique feature of the experiments is the use of specially prepared atomically flat or very low step density surfaces; this allows us to see how the liquid-like morphologies are associated with the steps and also allows the high temperature structures to survive the cooling process without being absorbed into the steps which normally would exist on a surface vicinal to (1 1 1). Quenched-in structures ascribed to pre-melting also act as sinks for diffusing ‘excess’ adatoms generated by the (1 × 1) to (7 × 7) transition and this leads to the formation of dendritic islands. 相似文献
170.
Kevin Dal Pont Jean‐François Gérard Eliane Espuche 《Journal of Polymer Science.Polymer Physics》2013,51(13):1051-1059
In this work, a novel nanocomposite series based on styrene‐butadiene rubber (SBR latex) and alpha‐zirconium phosphate(α‐ZrP) lamellar nanofillers is successfully prepared. The α‐ZrP lamellar filler is modified at the cation exchange capacity by γ‐aminopropyltrimethoxysilane and the filler surface modification is first discussed. A significant improvement of the mechanical properties is obtained by using the surface modified nanofillers. However, no modification of the gas barrier properties is observed. The impact of addition of bis(triethoxysilylpropyl)tetrasulfide (TESPT) as coupling agent in the system is discussed on the nanofiller dispersion state and on the filler–matrix interfacial bonding. Simultaneous use of modified nanofillers and TESPT coupling agent is found out with extraordinary reinforcing effects on both mechanical and gas barrier properties and the key factors at the origin of the improvement of these properties are identified. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 1051–1059 相似文献