共查询到20条相似文献,搜索用时 23 毫秒
1.
Lei Gao Yanyan Huang 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(2):165-171
The effective linear and nonlinear optical properties of metal/dielectric composite media, in which ellipsoidal metal inclusions
are distributed in shape, are investigated. The shape distribution function P(L
x, L
y) is assumed to be 2Δ-2θ(L
x - 1/3 + Δ/3)θ(L
y - 1/3 + Δ/3)θ(2/3 + Δ/3 - L
x - L
y), where θ( . . . ) is the Heaviside function, Δ is the shape variance and Li are the depolarization factors of the ellipsoidal inclusions along i-symmetric axes (i = x, y). Within the spectral representation, we adopt Maxwell-Garnett type approximation to study the effect of shape variance Δ
on the effective nonlinear optical properties. Numerical results show that both the effective linear optical absorption α
∼ ωIm() and the modulus of the effective third-order optical nonlinearity enhancement |χ(3)
e|/χ(3)
1 exhibit the nonmonotonic behavior with Δ. Moreover, with increasing Δ, the optical absorption and the nonlinearity enhancement
bands become broad, accompanied with the decrease of their peaks. The adjustment of Δ from 0 to 1 allows us to examine the
crossover behavior from no separation to large separation between optical absorption and nonlinearity enhancement peaks. As
Δ → 0, i.e., the ellipsoidal shape deviates slightly from the spherical one, the dependence of |χ(3)
e|/χ(3)
1 on Δ becomes strong first and then weak with increasing the imaginary part of inclusions' dielectric constant. In the dilute
limit, the exact formula for the effective optical nonlinearity is derived, and the present approximation characterizes the
exact results better than old mean field one does.
Received 10 December 2002 Published online 4 June 2003
RID="a"
ID="a"e-mail: lgaophys@pub.sz.jsinfo.net 相似文献
2.
H. Chamati 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,24(2):241-249
The finite-size critical properties of the (n) vector ϕ4 model, with long-range interaction decaying algebraically with the interparticle distance r like r
-d - σ, are investigated. The system is confined to a finite geometry subject to periodic boundary condition. Special attention
is paid to the finite-size correction to the bulk susceptibility above the critical temperature T
c. We show that this correction has a power-law nature in the case of pure long-range interaction i.e. 0 < σ < 2 and it turns out to be exponential in case of short-range interaction i.e.σ = 2. The results are valid for arbitrary dimension d, between the lower ( d
< = σ) and the upper ( d
> = 2σ) critical dimensions.
Received 2 July 2001 and Received in final form 4 Septembre 2001 相似文献
3.
R. Krücken S.J. Asztalos R.M. Clark M.A. Deleplanque R.M. Diamond P. Fallon I.Y. Lee A.O. Macchiavelli G.J. Schmid F.S. Stephens K. Vetter Jing-Ye Zhang 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):151-155
High-spin states in 112Pd were studied using prompt γ-ray spectroscopy with Gammasphere following heavy-ion-induced fission in the reaction 18O + 208Pb at 91 MeV. A new 8+ level at 2638 keV was discovered with transitions connecting it to the yrast band and the quasi-gamma band. The three, now
established, closely spaced 8+ states indicate a mixing between the ground-state band, s-band, and quasi-gamma band. Several high-spin structures with likely negative parity have been extended to higher spin and
it is proposed that they are based on the νh
11/2(g
7/2
d
5/2) and νh
11/2(s
1/2
d
3/2) configurations.
Received: 28 November 2000 / Accepted: 8 February 2001 相似文献
4.
G. Savona D.V. Livanov A.A. Varlamov 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(4):415-420
We study the fluctuation-induced magnetotransport of a two-dimensional superconductor in the quasiballistic regime, where
ξ
GL(T) ≪ ℓ (ℓ is the electron mean free path and ξ
GL(T) is the Ginzburg-Landau coherence length). The magnetoconductivity is evaluated in the nonlocal fluctuation regime thereby
extending the existing theory valid in the local limit. We show that the Maki-Thompson (MT) and density-of-states (DOS) contributions
strongly compensate each other and their sum is negligible in comparison with the Aslamazov-Larkin (AL) term. The hierarchy
of the fluctuation contributions to the magnetoconductivity in the high-field limit is also qualitatively discussed.
Received 10 July 2002 / Received in final form 21 November 2002 Published online 7 May 2003 相似文献
5.
V.Yu. Irkhin M.I. Katsnelson 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(3):401-408
The longitudinal and transverse nuclear magnetic relaxation rates 1/T
1(T) and 1/T
2(T) are calculated for three- and two-dimensional (3D and 2D) metallic ferro- and antiferromagnets (FM and AFM) with localized
magnetic moments in the spin-wave temperature region. The contribution of the one-magnon decay processes is strongly enhanced
in comparison with the standard T-linear Korringa term, especially for the FM case. For the 3D AFM case this contribution diverges logarithmically, the divergence
being cut at the magnon gap ω due to magnetic anisotropy, and for the 2D AFM case as ω-1. The electron-magnon scattering processes yield T
2ln(T/ω) and T
2/ω1/2-terms in 1/T
1 for the 3D AFM and 2D FM cases, respectively. The two-magnon (“Raman”) contributions are investigated and demonstrated to
be large in the 2D FM case. Peculiarities of the isotropic 2D limit (where the correlation length is very large) are analyzed.
Received 29 November 1999 and Received in final form 6 June 2000 相似文献
6.
D. Dantchev 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,23(2):211-219
The behavior of the bulk two-point correlation function G(;T| d ) in d-dimensional system with van der Waals type interactions is investigated and its consequences on the finite-size scaling properties
of the susceptibility in such finite systems with periodic boundary conditions is discussed within mean-spherical model which
is an example of Ornstein and Zernike type theory. The interaction is supposed to decay at large distances r as r
- (d + σ), with 2 < d < 4, 2 < σ < 4 and d + σ≤6. It is shown that G(;T| d ) decays as r
- (d - 2) for 1 ≪r≪ξ, exponentially for ξ≪r≪r
*, where r
* = (σ - 2)ξlnξ, and again in a power law as r
- (d + σ) for r≫r
*. The analytical form of the leading-order scaling function of G(;T| d ) in any of these regimes is derived.
Received 28 May 2001 相似文献
7.
R. Kumar D. Mehta N. Singh H. Kaur A. Görgen S. Chmel R.P. Singh S. Murlithar 《The European Physical Journal A - Hadrons and Nuclei》2001,12(1):5-8
The band structures built on the 5- isomeric state ( T
1/2 = 3.46 m) in the doubly odd 130Cs nucleus have been established up to I = 24? via the 124Sn(11B, 5n)130Cs reaction. The previously observed bands based on the πh
11/2⊗νh
11/2, πg
7/2⊗νh
11/2 and πd
5/2⊗νh
11/2 configurations and a positive-parity side band with multiple connections to the α = 0 signature partner of the yrast πh
11/2⊗νh
11/2 band have been extended to higher spins. A new band based on the πh
11/2⊗νg
7/2 configuration is observed. The yrast πh
11/2⊗νh
11/2 band exhibits anomalous signature splitting whose magnitude decreases up to spin 15 and then increases without restoring
the normal signature splitting.
Received: 20 February 2001 / Accepted: 9 May 2001 相似文献
8.
J. Horbach W. Kob K. Binder 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(4):531-543
We present the results of extensive molecular dynamics computer simulations in which the high frequency dynamics of silica,
i.e. for frequencies ν > 0.5 THz, is investigated in the viscous liquid state as well as in the glass state. We characterize the
properties of high frequency sound modes by analyzing J
l(q,ν) and J
t(q,ν), the longitudinal and transverse current correlation function, respectively. For wave-vectors q > 0.4 ?-1 the spectra are sitting on top of a flat background. The dynamic structure factor S(q,ν) exhibits for q > 0.23 ?-1 a boson peak which is located nearly independent of q around 1.7 THz and for which the intensity scales approximately linearly with temperature. We show that the low frequency
part of the boson peak is mainly due to the elastic scattering of transverse acoustic modes with frequencies around 1 THz.
The strength of this scattering depends on q and is largest around q = 1.7 ?-1, the location of the first sharp diffraction peak in the static structure factor. By studying S(q,ν) for different system sizes we show that strong finite size effects are present in the low frequency part of the boson
peak in that for small systems part of its intensity is missing. We discuss the consequences of these finite size effects
for the structural relaxation.
Received 27 June 2000 and Received in final form 9 January 2001 相似文献
9.
K.S. Kim Myung Ki Cheoun Yeungun Chung Hyung Joo Nam 《The European Physical Journal A - Hadrons and Nuclei》2001,11(2):147-154
New results for the double beta decay of 76
Ge are presented. They are extracted from data obtained with the HEIDELBERG-MOSCOW experiment, which operates five enriched
76
Ge detectors in an extreme low-level environment in the Gran Sasso underground laboratory. The two-neutrino-accompanied double
beta decay is evaluated for the first time for all five detectors with a statistical significance of 47.7 kg y resulting in
a half-life of T
1/2
2ν = [1.55±0.01(stat)+0.19
-0.15(syst)]×1021 y. The lower limit on the half-life of the 0νββ decay obtained with pulse shape analysis is T
1/2
0ν > 1.9×1025(3.1×1025) y with 90% C.L. (68% C.L.) (with 35.5 kg y). This results in an upper limit of the effective Majorana-neutrino mass of 0.35
eV (0.27 eV) using the matrix elements of A. Staudt et al.'s work (Europhys. Lett. 13, 31 (1990)). This is the most stringent limit at present from double beta decay. No evidence for a majoron-emitting decay
mode is observed.
Received: 22 August 2001 / Accepted: 18 October 2001 相似文献
10.
K.C. Chung C.S. Wang A.J. Santiago J.W. Zhang 《The European Physical Journal A - Hadrons and Nuclei》2001,11(2):137-141
The σ-ω coupling is introduced phenomenologically in the linear σ-ω model to study the nuclear matter properties. It is shown
that not only the effective nucleon mass M* but also the effective σ meson mass m
σ
* and the effective ω meson mass m
ω
* are nucleon-density-dependent. When the model parameters are fitted to the nuclear saturation point, with the nuclear radius
constant r
0 = 1.14 fm and volume energy a
1 = 16.0 MeV, as well as to the effective nucleon mass M
* = 0.85M, the model yields m
σ
* = 1.09m
σ and m
ω
* = 0.90m
ω at the saturation point, and the nuclear incompressibility K
0 = 501 MeV. The lowest value of K0 given by this model by adjusting the model parameters is around 227 MeV.
Received: 23 March 2001 / Accepted: 8 June 2001 相似文献
11.
S. Leenhardt O. Sorlin M.G. Porquet F. Azaiez J.C. Angélique M. Belleguic C. Borcea C. Bourgeois J.M. Daugas C. Donzaud I. Deloncle J. Duprat A. Gillibert S. Grévy D. Guillemaud-Mueller J. Kiener M. Lewitowicz S.M. Lukyanov F. Marie N.A. Orr Yu.-E. Penionzhkevich F. de Oliveira Santos F. Pougheon M.G. Saint-Laurent W. Shuying Yu. Sobolev J.S. Winfield 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):1-5
The reduced transition probability B(E2: 01
+→ 2+) of 72Zn has been measured for the first time by Coulomb excitation at intermediate energy. The result B(E2: 01
+→ 2+) = 1740±210 e2fm4, corresponds to the deformation parameter β2 of 0.23, in close agreement with expectations derived from the neighboring nucleus 73Zn. A discussion of the evolution of the N = 40 sub-shell closure as a function of Z is presented.
Received: 19 December 2001 / Accepted: 14 March 2002 相似文献
12.
A ππ, ˉKK, and ρρ(ωω) fully coupled channel model is used to predict the lowest isospin S, P, D, F-wave phase shifts and inelasticities
for elastic ππ scattering from threshold to 2.0 GeV. As input the S-matrix is required to exhibit poles corresponding to the
meson resonance table of the Particle Data Group. As expected, the ππ inelasticity is very strongly related to the opening
of the ˉK channel near 1 GeV, and the opening of ρρ(4π) and ωω(6π) channels in the 1.5 GeV region. The predictions of this model are
compared to the various elastic ππ→ππ amplitudes, that were obtained from analyses of π− p →π−π+n data. The role of the various resonances, in particular the glueball candidate f
0(1500) and the f
J(1710) is investigated.
Received: 19 November 1997 相似文献
13.
A. Díaz-Sánchez A. Pérez-Garrido 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,24(4):483-486
The relaxation of the specific heat and the entropy to their equilibrium values is investigated numerically for the three-dimensional
Coulomb glass at very low temperatures. The long time relaxation follows a stretched exponential function, f (t) = f
0exp - (t/τ)β
, with the exponent β increasing with the temperature. The relaxation time diverges as an Arrhenius law when T→ 0.
Received 24 May 2001 and Received in final form 12 September 2001 相似文献
14.
R.A. Radhi 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):387-392
Electron scattering Coulomb form factors for the single-particle quadrupole transitions in p-shell and sd-shell nuclei have been studied. Core polarization effects are included through a microscopic theory that includes excitations
from the core orbits up to higher orbits with 2ω excitations. The modified surface delta interaction is adopted as a residual
interaction. The results are discussed for the ( 1p
1/2
-1↦1p
3/2
-1) proton transition in 15N, ( 1d
5/2↦2s
1/2) neutron transition in 17O and ( 1d
3/2
-1↦2s
1/2
-1) proton transition in 39K. The inclusion of core polarization effects modifies the form factors markedly and describes the experimental data very
well in both the absolute strength and the momentum transfer dependence.
Received: 18 April 2002 / Accepted: 1 July 2002 / Published online: 6 March 2003
RID="a"
ID="a"e-mail: baguniv@uruklink.net
Communicated by A. Molinari 相似文献
15.
G. Migliorini V.G. Rostiashvili T.A. Vilgis 《The European physical journal. E, Soft matter》2001,4(4):475-487
A variational approach is considered to calculate the free energy and the conformational properties of a polyelectrolyte chain
in d dimensions. We consider in detail the case of pure Coulombic interactions between the monomers, when screening is not present,
in order to compute the end-to-end distance and the asymptotic properties of the chain as a function of the polymer chain
length N. We find R≃N
ν(log N)γ, where ν = and λ is the exponent which characterizes the long-range interaction U∝ 1/r
λ. The exponent γ is shown to be non-universal, depending on the strength of the Coulomb interaction. We check our findings
by a direct numerical minimization of the variational energy for chains of increasing size 24 < N < 215. The electrostatic blob picture, expected for small enough values of the interaction strength, is quantitatively described
by the variational approach. We perform a Monte Carlo simulation for chains of length 24 < N < 210. The non-universal behavior of the exponent γ previously derived within the variational method is also confirmed by the simulation
results. Non-universal behavior is found for a polyelectrolyte chain in d = 3 dimension. Particular attention is devoted to the homopolymer chain problem, when short-range contact interactions are
present.
Received 8 August 2000 and Received in final form 19 December 2000 相似文献
16.
J. Genevey J.A. Pinston H. Faust C. Foin S. Oberstedt M. Rejmund 《The European Physical Journal A - Hadrons and Nuclei》2000,9(2):191-195
In this work we have identified and studied the decay of two new microsecond isomers 19/2- and 23/2+ in 131Sb. This neutron-rich nucleus was produced by thermal neutron-induced fission of 241Pu. The detection is based on time correlation between fission fragments selected by the LOHENGRIN spectrometer at ILL (Grenoble)
and the γ-rays or conversion electrons from isomers. These new data on high-spin states complete the level scheme previously
obtained from β-decay. A large fraction of the members of the πg
7/2ν(h
11/2
-1
d
3/2
-1) and πg
7/2νh
11/2
-2 multiplets are now known and were compared with a multi-particle shell model calculation.
Received: 7 June 2000 / Accepted: 19 September 2000 相似文献
17.
Y. H. Zhang T. Hayakawa M. Oshima Y. Toh J. Katakura Y. Hatsukawa M. Matsuda N. Shinohara T. Ishii H. Kusakari M. Sugawara T. Komatsubara 《The European Physical Journal A - Hadrons and Nuclei》2000,8(4):439-442
High spin states in 178Ir have been studied via the 152Sm(31P, 5nγ)178Ir reaction through excitation functions, X-γ and γ-γ-t coincidence measurements. According to the band structure characteristics
and the measured intraband B(M1)/B(E2) ratios, two rotational bands are identified and assigned to be associated with the πh
9/2⊗νi
13/2 and πh
11/2⊗νi
13/2 configurations, respectively. Both bands show the signature inversion feature.
Received: 23 March 2000 / Accepted: 31 July 2000 相似文献
18.
Yu-bing Dong 《The European Physical Journal A - Hadrons and Nuclei》1998,1(3):347-354
In this paper, the spin-dependent structure functions of nucleon g
1, and photoabsorption cross sections σ1/2, σ3/2 and σT in the resonance region are estimated based on the constituent quark model and the properties of the five phenomenological
Breit-Wigner resonances P
33(1232), S
11(1535), D
13(1520), P
11(1440), and F
15(1680). Our results are compared to the recent E143 data of the polarized structure functions g
1(W
2, Q
2) at points Q
2=0.5 GeV2 and Q
2=1.2 GeV2 and the data of the total inclusive photoabsorption cross sections.
Received: 7 October 1997 相似文献
19.
Summary The relaxation processes of glass-forming polymethylacrylate have been studied in a wide temperature range above the glass
transition temperatureT
g by means of light scattering measurements. Experimental spectra give evidence of a self-similar behaviourI(ω) ∝ ω−(1−a) over a spectral range of 2–3 decades, consistent with the predictions of the mode-coupling theory. Different from the prediction
of the theory, the value ofa is strongly temperature dependent. This behaviour has been attributed to the presence of a slow secondary relaxation located
in the GHz frequency region, whose strength progressively increases with temperature.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
20.
T. Rzaca-Urban W. Urban A. Kaczor J.L. Durell M.J. Leddy M.A. Jones W.R. Phillips A.G. Smith B.J. Varley I. Ahmad L.R. Morss M. Bentaleb E. Lubkiewicz N. Schulz 《The European Physical Journal A - Hadrons and Nuclei》2000,9(2):165-169
Neutron-rich, 88-94Kr nuclei, populated in spontaneous fission of 248Cm, have been studied with EUROGAM 2, by measuring prompt γ-rays. Many new excited states in even-even Kr isotopes have been
identified. For the first time spins and parities were determined experimentally in these nuclei. Our results indicate that
the quadrupole deformation of Kr isotopes will appear only above N = 58, as observed in Sr and Zr nuclei. The newly found 3- level at 1506.4 keV in 90Kr suggests the exsistence of a new region of increased octupole correlations, probably associated with the ν(d
5/2
h
11/2) pair of Δl = Δj = 3 orbitals.
Received: 18 September 2000 / Accepted: 18 October 2000 相似文献