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1.
Juraj Kumičák 《Czechoslovak Journal of Physics》1999,49(4):527-537
A model of 1/f noise is considered, based on moving averages of ordern. The coefficientsα
k
defining the model are calculated numerically using Seidel iteration which turns out to converge rapidly. The convergence
is independent ofn which seems to be caused by the fact that the nonlinear problem solved is defined by a self-similar matrix. The coefficientsα
k
appear to approach, with indefinitely growingn, valuesα
k
=1/√k and thus the model has a kind of Fourier invariance. Physical interpretation of the invariance is suggested as well
as of coefficientsα
k
describing long-range correlations. Fractal sets of dimensiond=2.5 are proposed to play certain role in explaining the latter.
This work was partly supported by the Scientific Grant Agency of the Ministry of Education of Slovak Republic (VEGA) under
the Grant No. 1/3143/96 and by the Slovak Literary Fund. 相似文献
2.
G. V. Efimov 《Communications in Mathematical Physics》1967,7(2):138-151
Space-time properties of a class of relativistic invariant distributions of the type were considered for different sequences of coefficientsc
n
. 相似文献
3.
The electron localization is studied for Anderson's tight-binding model with diagonal and off-diagonal disorder for a very large square lattice (10,000 sites) and diamond lattice (27,000 sites). The numerical investigations are based on the Lanczos recursion method. The convergence of the recursion coefficientsa
n
,b
n
is discussed with regard to the electron localization.From Anderson's criterion and an exact real space renormalization method the energy of the localization edge is found as a function of the degree of disorder. Also the dependence of the spatial decay rate of localized wave functions on the energy and the degree of disorder is evaluated. Near the Anderson transition, where all states become localized, we get two critical exponentsv
E
andv
W
, which lead us to the tentative suggestion of multicritical scaling laws for this transition. 相似文献
4.
Zheng Wen-Chen 《Il Nuovo Cimento D》1990,12(12):1667-1671
Summary A uniform und simple method suitable to alld
n
ions is established for the calculation of spin-lattice coupling coefficientsG
11 andG
44 inT
d
symmetry. According to the method, the coefficientsG
11 andG
44 for Fe3+ ion in GaP crystal have been obtained from the high-order perturbation formulae of zero-field splitting in tetragonal and
trigonal fields based on the spin-orbit coupling mechanism. The calculated results show good agreement with the experimental
findings.
The author of this paper has agreed to not receive the proofs for correction.
The project supported by National Natural Science Foundation of China. 相似文献
5.
Karl W. Kratky 《Journal of statistical physics》1982,29(1):129-138
The virial coefficients Bn of the pressure of a thermodynamic system can be represented in terms of graphs. The recently defined overlap graphs are studied in detail. Furthermore, the overlap graph representation of the sixth and seventh virial coefficientsB
6 andB
7) is determined. 相似文献
6.
A left-unilateral matrix equation is an algebraic equation of the form a
0+a
1
x+a
2
x
2+·+a
n
x
n
=0 where the coefficients a
r
and the unknown x are square matrices of the same order and all coefficients are on the left (similarly for a right-unilateral equation). Recently certain perturbative solutions of unilateral equations and their properties have been discussed. We present a unified approach based on the generalized Bezout theorem for matrix polynomials. Two equations discussed in the literature, their perturbative solutions and the relation between them are described. More abstractly, the coefficients and the unknown can be taken as elements of an associative, but possibly noncommutative, algebra. 相似文献
7.
I. Nezbeda 《Czechoslovak Journal of Physics》1985,35(7):752-767
The table of the virial coefficientsB
2 throughB
4 of all hard body fluid models considered so far has been completed by calculating the missing coefficients. Applicability of these coefficients to predicting the thermodynamic behaviour of dense hard body fluids is assessed and certain discrepancies in the data for oblate spherocylinders are found. It is shown that by combining the Padé approximant with an appropriate analytic expression an accurate 3-parameter equation of state results. 相似文献
8.
The dynamic structure of liquid s-triazine has been studied by analysing the deuterium and nitrogen-14 quadrupolar relaxation data of d 3-s-triazine. The molecular motions are markedly anisotropic with: (a) fast, large angle jump, inertial type in-plane motions of almost zero activation enthalpy and large negative activation entropy; (b) comparatively slow, small angle jump, rotational diffusion type, out of plane motions of higher activation enthalpy and small activation entropy. Comparison of the data on the dynamic behaviour of pyridine [3] and benzene [4] with the present ones on s-triazine leads to a general picture of molecular motions of planar hexagonal rotors in the liquid state (at atmospheric pressure). The behaviour of pyridine, which has a dipole moment departs somewhat from the more similar (and more anisotropic) behaviour of benzene and s-triazine. These results also support our previous finding of motional anisotropy in liquid pyridine [3]. A pictorial representation of the motional anisotropy in benzene, pyridine and s-triazine is giving using motional ellipsoids whose axes lengths are proportional to the diffusion constants. 相似文献
9.
Zheng Wen-Chen 《Il Nuovo Cimento D》1991,13(6):735-739
Summary From a uniform and simple method suitable to alld
n ions for the calculation of the spin-lattice coupling coefficientsG
11 andG
44 inT
d symmetry, the analytic expressions ofG
11 andG
44 ford
7 ions in this symmetry have been obtained from the high-order perturbation formulae of zero-field splitting in low symmetries
based on the weak-field approximation. By using these expressions, the coefficientsG
11 andG
44 for Co2+ ion in ZnS crystal have been calculated and the signs of these coefficients are also given. The absolute values of the calculated
results show good agreement with the observed values and the signs of these coefficients remain to be verified experimentally.
The author of this paper has agreed to not receive the proofs for correction.
The project was supported by National Natural Science Foundation of China. 相似文献
10.
Y.B. Duan L. Wang W.J. Qian 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(1):25-29
A non-partial-wave Coulomb-Born theory is recently formulated to treat the excitation of many-electron atomic ions for impact
by an arbitrary charged particle [Y.B. Duan et al., Phys. Rev. A 56, 2431 (1997)]. The multiple expansion of the transition matrix element is decomposed into the target form factor and the
projectile form factor. These are the matrix elements of the tensor operators between quantum states so that any complicated
wave function for the target ion can be employed. In this formal theory, an infinitesimally small positive quantity is introduced artificially to guarantee the convergence of integrals. As a supplementary part of the theory, we discuss how
to choose the value of . It is found that the should be taken as functions of the momentum transfer and multipolarity . Illustrations are carried out by calculating the cross-sections for some typical transitions n
a
l
a
-n
b
l
b
of hydrogen-like ions for impact by electron, positron, and proton, respectively. The resulting cross-sections are in good
agreement with ones produced by using a method available for ion targets with Slater-type orbitals [N.C. Deb, N.C. Sil, Phys.
Rev. A 28, 2806 (1993)]. Comparisons demonstrate that the Coulomb-Born theory with non-partial wave analysis provides a powerful method
to treat the excitation of many-electron atomic ions impact by an arbitrary charged particle.
Received 6 April 1999 相似文献
11.
E. L. Korotyaev 《Russian Journal of Mathematical Physics》2011,18(4):427-439
The Jacobi operator (Jf)
n
= a
n−1
f
n−1 +a
n
f
n+1 + b
n
f
n
on ℤ with real finitely supported sequences (a
n
− 1)
n∈ℤ and (b
n
)
n∈ℤ is considered. The inverse problem for two mappings (including their characterization): (a
n
, b
n
, n ∈ ℤ) → {the zeros of the reflection coefficient} and (a
n
, b
n
, n ∈ ℤ) → {the eigenvalues and the resonances} is solved. All Jacobi operators with the same eigenvalues and resonances are
also described. 相似文献
12.
It is shown that the pair correlation function (which is by definition the high-density factor in the revised Enskog theory) is not always a well-defined functional of the local density. Moreover, for a finite system with periodic boundary conditions and in the space homogeneous case, this function, computed at the contact value, is bounded at the maximum allowed density (i.e., a densityn
max such that, in one dimension, 1/a–1/Ln
max<1/a; equality sign, which corresponds to the usual close-packing density for whichL/a is an integer, being included as a particular case). At least for the one-dimensional gas model this finite value is shown to approach infinity in the thermodynamic and in the hydrodynamic limits. A new form for the revised Enskog equation, which does not depend on the inverse conjecture, is finally given. 相似文献
13.
A simple M-shaped model has been proposed for the density of states of the π bands of the graphene. The model has been used to derive
the expression for the local density of states on the adsorbed atom and to calculate the corresponding occupation numbers
for different model parameters. Additional simplifications have made it possible to represent the band contribution n
b
to the total occupation number of the adatom n
a
in the analytical form. The contributions of local states n
l
to n
a
= n
b
+ n
l
have been calculated for different parameters. The charge has been numerically evaluated for the case of adsorption of alkali
metal atoms on the graphene. The results obtained have been verified using the model of a surface diatomic molecule calculated
by the Harrison bond-orbital method. The verification has demonstrated that the charges calculated in terms of radically different
models are in good agreement. 相似文献
14.
The adiabatic hyperspherical approach (AHSA) is applied for the numerical investigation of the scattering processes and resonances
in Coulomb three-body mesic atomic systems. The results of the calculations of elastic and inelastic cross sections in low-energy
collisions aμ + b (a, b = p, d,
t), energies, lifetimes and local characteristics of resonant states of mesic molecular ions
n
Heaμ+ (n = 3, 4) are presented.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
15.
István Lagzi 《Pramana》2005,64(2):291-298
Formation of 1D Liesegang patterns was studied numerically in precipitation and reversible complex formation of precipitate
scenarios in an electric field. The Ostwald’s supersaturation model reported by Buki, Kárpáti-Smidróczki and Zrínyi (BKZ model)
was extended further. In the presence of an electric field the position of the first and the last bands (X
n) measured from the junction point of the outer and the inner electrolytes can be described by the functionX
n =a
1τ
n
1/2
+a
2τn +a
3, where τn is the time elapsed until the nth band formation,a
1,a
2 anda
3 are constants. The variation of the total number of bands with different electric field strengths (ε) has a maximum. For
higher ε one can observe a moving precipitation zone that becomes wider due to precipitation and reversible complex formation. 相似文献
16.
E. L. Ivchenko V. P. Kochereshko A. V. Platonov D. R. Yakovlev A. Waag W. Ossau G. Landwehr 《Physics of the Solid State》1997,39(11):1852-1858
Theory of specular light reflection from long-period quantum-well structures taking into account the exciton contribution
to dielectric polarization has been developed for an arbitrary relation between the background refractive index in the well,
n
a, and barrier-material refractive index nb. General expressions for the optical reflection and transmission coefficients for a structure with N equidistant quantum wells are derived with the use of the Green’s function and transfer matrix methods. Normal and oblique
light reflectance spectra from II-VI-based heterostructures were found to reveal a bright interference pattern caused by the
difference between n
a and n
b. A comparison of the theory with experiment has yielded the dispersion of n
a and n
b within a broad wavelength range and the parameters of the quasi-two-dimensional heavyhole exciton (e1-hh1), namely, the resonant frequency and the radiative and nonradiative damping rates. Reflectance spectra from resonant Bragg
and quasi-Bragg structures with real exciton parameters are calculated, and the effect on these spectra of the refractive-index
difference and the deviation from the Bragg condition is analyzed.
Fiz. Tverd. Tela (St. Petersburg) 39, 2072–2078 (November 1997) 相似文献
17.
Benedetto Scoppola 《Journal of statistical physics》2011,143(3):413-419
A class of families of Markov chains defined on the vertices of the n-dimensional hypercube, Ω
n
={0,1}
n
, is studied. The single-step transition probabilities P
n,ij
, with i,j∈Ω
n
, are given by
Pn,ij=\frac(1-a)dij(2-a)nP_{n,ij}=\frac{(1-{\alpha})^{d_{ij}}}{(2-{\alpha})^{n}}, where α∈(0,1) and d
ij
is the Hamming distance between i and j. This corresponds to flip independently each component of the vertex with probability
\frac1-a2-a\frac{1-{\alpha}}{2-{\alpha}}. The m-step transition matrix Pn,ijmP_{n,ij}^{m} is explicitly computed in a close form. The class is proved to exhibit cutoff. A model-independent result about the vanishing
of the first m terms of the expansion in α of Pn,ijmP_{n,ij}^{m} is also proved. 相似文献
18.
In this paper we employ the hydrodynamic formulation of time-dependent density functional theory to obtain the van der Waals
coefficientsC
6
andC
8
of alkali metal clusters of various sizes including very large clusters. Such calculations become computationally very demanding
in the orbital-based Kohn-Sham formalism, but are quite simple in the hydrodynamic approach. We show that for interactions
between the clusters of the same sizes,C
6
andC
8
scale as the sixth and the eighth power of the cluster radius, respectively, and approach their classically predicted values
for the large size clusters. 相似文献
19.
C. Y. He X. Q. Li L. H. Zhu X. G. Wu Y. Liu B. Pan L. H. Li Z. M. Wang G. S. Li Z. Y. Li S. Y. Wang Q. Xu J. G. Wang H. B. Ding J. Zhai 《The European Physical Journal A - Hadrons and Nuclei》2010,43(1):1-4
Up to now, no experimental cross-section data exist for the 67Zn (n,a \alpha) 64Ni reaction in the MeV neutron energy region. In the present work, the cross-section of the 67Zn (n,a \alpha) 64Ni reaction was measured at E
n = 6.0 MeV. Experiments were performed at the Van de Graaff accelerator of Peking University, China. Fast neutrons were produced
through the D (d, n) 3He reaction using a deuterium gas target. Absolute neutron flux was determined by a small 238U fission chamber and a BF3 long counter was used as a neutron flux monitor. A twin gridded ionization chamber was employed as the a \alpha -particle detector and two back-to-back 67Zn samples were used for a \alpha events measurement. Background was measured and subtracted from foreground. The measured cross-section of the 67Zn (n,a \alpha) 64Ni reaction was 7.3 (1±15%) mb at 6.0MeV. The present result was compared with existing evaluations and TALYS code calculations. 相似文献
20.
Dielectronic recombination and resonant transfer excitation processes for helium-like krypton
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The relativistic configuration interaction method is employed to calculate the dielectronic recombination(DR) cross sections of helium-like krypton via the 1s2lnl ’(n = 2,3,...,15) resonances.Then,the resonant transfer excitation(RTE) processes of Kr 34+ colliding with H,He,H 2,and CH x(x = 0-4) targets are investigated under the impulse approximation.The needed Compton profiles of targets are obtained from the Hartree-Fock wave functions.The RTE cross sections are strongly dependent on DR resonant energies and strengths,and the electron momentum distributions of the target.For H 2 and H targets,the ratio of their RTE cross sections changes from 1.85 for the 1s2l2l ’ to 1.88 for other resonances,which demonstrates the weak molecular effects on the Compton profiles of H 2.For CH x(x = 0-4) targets,the main contribution to the RTE cross section comes from the carbon atom since carbon carries 6 electrons;as the number of hydrogen increases in CH x,the RTE cross section almost increases by the same value,displaying the strong separate atom character for the hydrogen.However,further comparison of the individual orbital contributions of C(2p,2s,1s) and CH 4(1t 2,2a 1,1a 1) to the RTE cross sections shows that the molecular effects induce differences of about 25.1%,19.9%,and 0.2% between 2p-1t 2,2s-2a 1,and 1s-1a 1 orbitals,respectively. 相似文献