共查询到20条相似文献,搜索用时 31 毫秒
1.
Hans -Otto Heuer 《Journal of statistical physics》1993,72(3-4):789-827
Extensive Monte Carlo simulations have been performed to analyze the dynamical behavior of the three-dimensional Ising model with local dynamics. We have studied the equilibrium correlation functions and the power spectral densities of odd and even observables. The exponential relaxation times have been calculated in the asymptotic one-exponential time region. We find that the critical exponentz=2.09 ±0.02 characterizes the algebraic divergence with lattice size for all observables. The influence of scaling corrections has been analyzed. We have determined integrated relaxation times as well. Their dynamical exponentz
int agrees withz for correlations of the magnetization and its absolute value, but it is different for energy correlations. We have applied a scaling method to analyze the behavior of the correlation functions. This method verifies excellent scaling behavior and yields a dynamical exponentz
scal which perfectly agrees withz. 相似文献
2.
O. K. Bazyl’ V. Ya. Artyukhov G. V. Maier G. B. Tolstorozhev T. F. Raichenok I. V. Skornyakov O. I. Shadyro V. L. Sorokin G. A. Ksendzova 《Optics and Spectroscopy》2012,112(2):223-232
We have measured the absorption and fluorescence spectra and fluorescence quantum yields of sulphone-containing anti-HIV active
o-aminophenol molecules in an inert solvent, hexane, and in a polar solvent, acetonitrile. We have studied IR Fourier-transform
spectra and examined structural features of o-aminophenols with different substituents in solutions and crystals. Functional groups of molecules that are involved in the
formation of hydrogen bonds have been revealed. Proton acceptor properties of o-aminophenol molecules have been theoretically evaluated using the method of molecular electrostatic potential. Using quantum
chemistry methods, we have calculated and interpreted absorption and fluorescence spectra of o-aminophenols. Calculation data are compared with experimental results. We have determined the main channels and mechanisms
of photophysical relaxation processes in o-aminophenols. 相似文献
3.
We have obtained the energy eigenvalues and the corresponding eigenfunctions for the generalized double-well potential in
the non-relativistic Schr?dinger equation. We have calculated the creation and annihilation operators directly from the eigenfunction
and we have shown these operators satisfy the commutation relation of the SU(2) group. We have expressed the Hamiltonian in terms of the su(2) algebra. Some interesting result including the standard symmetrical double-well potential, reflectionless-type potential
and V
0tanh 2(r/d) potential are also discussed. 相似文献
4.
We have studied the roughness and the dynamics of the contact line of a viscous liquid on a disordered substrate. We have
used photolithographic techniques to obtain a controlled disorder with a correlation length ξ = 10μm. Liquids with different
viscosity were used: water and aqueous glycerol solution. We have found that the roughness W of the contact line depends neither on the viscosity nor on the velocity v of the contact line for v in the range 0.2-20μm/s. W is found to scale with the length L of the line as L
ζ with a roughness exponent ζ = 0.51±0.03. This value is similar to the one obtained with superfluid helium. In the present
experiment, we have checked that the motion of the contact line is actually overdamped, so that the phenomenological equation
first proposed by Ertas and Kardar should be relevant. However, our measurement of ζ is in disagreement with the predicted
value ζ = 0.39. We have also analyzed the avalanche-like motion of the contact line. We find that the size distribution does
not follow a power law dependence.
Received 18 April 2002 相似文献
5.
Chayan Ranjit Shuvendu Chakraborty Ujjal Debnath 《International Journal of Theoretical Physics》2012,51(7):2180-2207
We have considered N-dimensional Einstein field equations in which four-dimensional space-time is described by a FRW metric and that of extra dimensions by an Euclidean metric. We have chosen the exponential forms of scale factors a and d numbers of b in such a way that there is no singularity for evolution of the higher dimensional Universe. We have supposed that the Universe is filled with K-essence, Tachyonic, Normal Scalar Field and DBI-essence. Here we have found the nature of potential of different scalar field and graphically analyzed the potentials and the fields for three scenario namely Emergent Scenario, Logamediate Scenario and Intermediate Scenario. Also graphically we have depicted the geometrical parameters named statefinder parameters and slow-roll parameters in the higher dimensional cosmology with the above mentioned scenarios. 相似文献
6.
Ambresh Shivaji Subhadip Mitra Pankaj Agrawal 《The European Physical Journal C - Particles and Fields》2012,72(3):1922
In order to solve the hierarchy problem, several extra-dimensional models have received considerable attention. We have considered
a process where a Higgs boson is produced in association with a KK-graviton (G
KK) at the LHC. At the leading order, this process occurs through the gluon fusion mechanism gg→hG
KK via a quark loop. We compute the cross section and examine some features of this process in the ADD model. We find that the
quark in the loop does not decouple in the large quark-mass limit just as in the case of gg→h process. We compute the cross section of this process for the case of the RS model also. We examine the feasibility of this
process being observed at the LHC. 相似文献
7.
M. V. Parkhats V. A. Galievskii E. S. Zharnikova V. N. Knyukshto S. V. Lepeshkevich A. S. Stashevskii T. V. Trukhacheva B. M. Dzhagarov 《Journal of Applied Spectroscopy》2011,78(2):278-285
We have used luminescence and absorption spectroscopy to study the dynamics of photosensitized singlet oxygen generation and
the photophysical characteristics of chlorin e
6 in Photolon ointment. We have shown that dimethylsulfoxide and polyethylene glycol 400, in concentrations comparable with
their content in the ointment form of the drug Photolon, do not lead to appreciable changes in the spectral characteristics
of chlorin e
6. Substantial changes in the photophysical characteristics of the photosensitizer are observed at significantly higher concentrations
of the excipients in the ointment. We have shown that in buffer solution, chlorin e
6 forms a complex with polyethylene glycol 1500. For the first time, we have detected luminescence of singlet oxygen from the
surface of biological tissue treated with Photolon ointment. 相似文献
8.
We have performed a Monte Carlo simulation study of a system of ellipsoidal particles with donor—acceptor sites modelling complementary hydrogen-bonding groups in real molecules. We have considered elongated Gay—Berne particles with terminal interaction sites allowing particles to associate and form dimers. The changes in the phase transitions and in the molecular organization and the interplay between orientational ordering and dimer formation are discussed. Particle flip and dimer moves have been used to increase the convergency rate of the Monte Carlo (MC) Markov chain. 相似文献
9.
W. Ouerghui A. Melliti M.A. Maaref J. Bloch 《Physica E: Low-dimensional Systems and Nanostructures》2005,28(4):519-524
We report systematic temperature-dependent measurements of photoluminescence spectra in self-assembled InGaAs/InAs/GaAs quantum dots (QDs). We have studied the rise in temperature of the ground-state homogeneous linewidth.A theoretical model is presented and accounts for the phonon-assisted broadening of this transition in individual QD. We have estimated the homogeneous linewidth of an individual QD from PL spectra of self-organized InAs/GaAs QDs by isolating the PL of each individual QD and fitting the narrow line associated with self-organized QDs through a Lorentzian convoluted by a Gaussian. We have observed a strong exciton–LO–phonon coupling (γLO) which becomes the dominating contribution to the linewidth above the temperature of 45 K. We have also derived the activation energy (ΔE) of the exciton–LO–phonon coupling, zero temperature linewidth (Γ0) and the exciton-LA-phonon coupling parameter (γAc). We report that our values are close to the values found in the literature for single InGaAs QD and InAs QD. 相似文献
10.
M. Ausloos K. Ivanova 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,20(4):537-541
We have searched for correlations and anticorrelations with respect to currencies as CHF, DKK, JPY, and USD in order to understand
the EUR behavior. In order to do so we have invented a false euro (FEUR) dating back to 1993 and have derived simulated exchange rates of the FEUR. Within the Detrended Fluctuation Analysis (DFA) statistical method we have obtained the power law behavior describing the rms. deviation of the fluctuations as a function
of time. We have compared the time-dependent exponent for these four exchange rates, and observe the role of the DEM, and
the other currencies forming the EUR. A simple investment strategy based on the local DFA technique shows one can obtain appreciable gains, even taking into account some modest transaction fee. We compare the
time dependent α exponent of the DFA for various exchange rates as in a correlation matrix for estimating respective influences.
Received 31 August 2000 相似文献
11.
We study the effect of bond angle and dihedral angle disorder on the diamagnetic susceptibility (χ) of a model amorphous semiconductor by adopting a linear combination of hybrids formalism. We have constructed orthormal
basis states for the disorder network by introducing distortion in bond angles and dihedral angles. We have used the disorder
basis states in the expression for χ and adopted suitable averaging techniques to obtain χ in terms of disorder parameters, which shows interesting results.
相似文献
12.
Chetan Limbachiya Minaxi Vinodkumar Mohit Swadia K.N. Joshipura Nigel Mason 《Molecular physics》2013,111(1):55-62
We report total inelastic, total ionisation and summed total excitation cross sections for electron scattering on furan, tetrahydrofuran (THF) and 2,5-dimethylfuran at energies between the ionisation threshold and 5 keV. We have employed the spherical complex optical potential formalism (SCOP) to calculate the total inelastic cross sections (Qinel) and have used complex scattering potential-ionisation contribution (CSP-ic) method to derive total ionisation cross sections (Qion) and summed total excitation cross sections (∑Qexc) from the calculated Qinel. We have also computed Qion for these molecules using binary-encounter-Bethe (BEB) approach. We have compared our total cross sections (TCS) with available experimental as well as previous theoretical results and have found good agreement. The results are presented graphically as well as numerically. 相似文献
13.
Takanori Matsumoto Susumu Saito 《Physica E: Low-dimensional Systems and Nanostructures》2005,29(3-4):560
We present the first-principles investigation of the transport properties of nanotubes connected to metal electrodes under external bias potential. We have developed the technique to calculate the current–voltage (I–V) curves by using the local-density approximation in the density-functional theory. We apply this technique to Al-nanotube-Al systems with different contact geometries regarding the position, the orientation, and the distance of nanotube to the electrode. These different geometries at contact can play an important role in the transport properties. The I–V curves have the different behaviors although the nanotube is connected to the same electrode. The transmission rate from one electrode to the other electrode shows strong dependence on the contact geometry. 相似文献
14.
We introduce a general method in order to construct the nonchiral fusion rules which determine the operator content of the operator product algebra for rational conformal field theories. We are particularly interested in the models of the complementary D-like solutions of the modular invariant partition functions with cyclic center Z
N
. We find that the nonchiral fusion rules have a Z
N
-grading structure. 相似文献
15.
Rinaldo Schinazi 《Journal of statistical physics》1993,71(3-4):507-511
We consider branching Markov chains on a countable set. We give a necessary and sufficient condition in terms of the transition kernel of the underlying Markov chain to have two phase transitions. We compute the critical values. We apply this result to prove that asymmetric branching random walks onZ have two phase transitions. 相似文献
16.
Jérôme Buzzi 《Communications in Mathematical Physics》1999,208(1):25-54
We consider random piecewise smooth, piecewise invertible maps mainly on the interval but also in higher dimensions. We assume
that, on the average and possibly without any stochastic uniformity: (i) the maps expand distances, (ii) do not have too many pieces, (iii) do not have too large a distortion, and (iv) are
strongly mixing. We assume {\it no Markov property}. We prove that as in the classical case of the iteration of a fixed piecewise
expanding map of the interval, we have {\it exponential decay of random correlations}. Our proof builds on the one given by
C.~Liverani for deterministic, mixing and piecewise expanding interval maps.
We demand very little of the stochastic process giving the maps. In particular, if the maps are β-transformations on , i.e., with affine, then our results apply to all stationary and ergodic processes which expand on the average and satisfy the mixing condition above.
We remark that our setting does not imply fast decay of
integrated
correlations.
Received: 16 November 1998 / Accepted: 11 May 1999 相似文献
17.
We assume: (i) Photons are emitted by harmonically oscillating sources. (ii) They have definite trajectories. (iii) They have a probability of being scattered at a slit. (iv) Detectors, like sources, are periodic. (v) Photons have positive and negative states which locally interfere, i.e., annihilate each other, when being absorbed. In this framework we are able to derive standard diffraction and interference results. We thereby eliminate in this approach wave-particle duality for photons, and give nonparadoxical answers to standard questions about interference. For example, in the two-slit experiment each photon goes through only one slit. 相似文献
18.
We study degenerations of the Belavin R-matrices via the infinite dimensional operators defined by Shibukawa–Ueno. We define a two-parameter family of generalizations of the Shibukawa–Ueno R-operators. These operators have finite dimensional representations which include Belavin's R-matrices in the elliptic case, a two-parameter family of twisted affinized Cremmer–Gervais R-matrices in the trigonometric case, and a two-parameter family of twisted (affinized) generalized Jordanian R-matrices in the rational case. We find finite dimensional representations which are compatible with the elliptic to trigonometric and rational degeneration. We further show that certain members of the elliptic family of operators have no finite dimensional representations. These R-operators unify and generalize earlier constructions of Felder and Pasquier, Ding and Hodges, and the authors, and illuminate the extent to which the Cremmer–Gervais R-matrices (and their rational forms) are degenerations of Belavin's R-matrix. 相似文献
19.
Archana Singh Mahendra Aynyas Sankar P. Sanyal 《Central European Journal of Physics》2009,7(1):102-107
We have predicted the phase transition pressure (P
T
)and high pressure behavior of Zirconium and Niobium carbide (ZrC, NbC). The high pressure structural phase transitions in
ZrC and NbC has been studied by using a two body inter-ionic potential model, which includes the Coulomb screening effect,
due to the semi-metallic nature of these compounds. These transition metal carbides have been found to undergo NaCl (B1) to CsCl (B2)-type structural phase transition, at high pressure like other binary systems. We predict such structural transformation
in ZrC and NbC at a pressure of 98GPa and 85GPa respectively. We have also predicted second order elastic constant and bulk
modulus. The present theoretical work has been compared with the corresponding experimental data and prediction of LAPW and
GGA and LDA theories.
相似文献
20.
The total (elastic + inelastic) cross sections fore
+ impact on alkaline-earth elements from Be to Ra are calculated by employing a complex spherical optical potential. This potential
has static, polarization and absorption components. The positron energy range is from a few eV to several thousand eV. We
have compared our elastic cross sections for Mg and Ca with the other available results and the agreement is good for energies
above 100eV. We have also compared our absorption cross sections withe
− ionization cross sections at high energies where our absorption cross sections are in good accord. We have made Bethe plots
fore
+ scattering on these elements. 相似文献