bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some examples of negative feedback in the Earth climate system
Authors: Kärner Olavi 
Published: August 2006

Abstract
Temporal variability of daily time series for total solar irradiance at the top of the atmosphere, the Microwave Sounding Unit (MSU) based global, hemispherical and zonal average temperature for the lower troposphere and stratosphere together with 5 surface air temperature data, measured at various meteorological stations have been studied by means of the structure function. From the growth rate of the structure function in the time interval between 32 and 4096 days it follows that the variability of the series represents an anti-persistent (AP) behavior. This property in turn shows a domination of negative feedback in the physical system generating the lower tropospheric temperature variability. Distribution of the increments over various ranges and correlations between them are calculated in order to determine the quantitative characteristics describing temporal variability.
Classical simulations of magnetic structures for chromium clusters: Size effects
Authors: Proykova Ana , Stauffer Dietrich 
Published: August 2006

Abstract
Classical (Heisenberg) simulations show that the total magnetization of the lowest-energy states of clusters made of antiferromagnetically coupled chromium atoms is planar, rather than collinear, depending on the arrangement of the atoms. Although the model Hamiltonian is not restrictive, many cluster configurations of various numbers of atoms do not use all three directions for the spins. This result confirms the conclusion drawn from the local-spin DFT calculation by Kohl and Bertsch that clusters of N≤13 have non-collinear magnetic moments. The present simulations show non-collinear spin ordering also for bigger clusters, designed to be as spherical as possible following the bcc arrangement, when atoms interact both with the nearest and next-nearest neighbours. Depending on the signs of the coupling constants frustration appears. The advantage of the discrete model, despite the simplicity, is that very large clusters and magnetization at finite temperatures can be studied. This model predicts that clusters with specific numbers of atoms interacting only with the nearest neighbours have collinear spins as in the bulk. We also apply the model to simulate the destruction of the anti-ferromagnetic ordering by thermal fluctuations. This model shows no unique magnetization of mixed Fe
0.33
Cr
0.67, which is consistent with experimental observations.
Transverse magnetic scattering of two incident plane waves by a dielectric coated cylindrical reflector
Authors: Mushref Muhammad 
Published: August 2006

Abstract
Scattering characteristics of two plane waves are investigated for a circular cylinder covered by a dielectric substance. Fields are assumed to be transverse magnetic (TM) and represented in an exponential series form. The diffracted radiations are found by applying the boundary conditions to the wave functions. The wave transformation method and the orthogonality of the exponential functions are respectively employed to obtain an infinite series in the solution. Numerical results are evaluated by reducing the infinite series to a finite number of terms and comparing estimates with the single plane wave scattering situation.
On the size dependence of surface tension in the temperature range from melting point to critical point
Authors: Sdobnyakov Nickolay , Samsonov Vladimir 
Published: August 2006

Abstract
The problem of size dependence of surface tension was investigated in view of a more general problem of the applicability of Gibbs’ thermodynamics to nanosized objects. For the first time, the effective surface tension (coinciding with the specific excess free energy for an equimolecular dividing surface) was calculated within a wide temperature range, from the melting temperature to the critical point, using the thermodynamic perturbation theory. Calculations were carried out for Lennard-Jones and metallic nanosized droplets. It was found that the effective surface tension decreases both, with temperature and particle size.
An explanation of optical phenomena in non-crystalline semiconductors
Authors: Banik Ivan 
Published: August 2006

Abstract
Barrier model of a non-crystalline semiconductor is described in this article. The most important optical phenomena, which are typical for this group of materials, are explained on the base of this model. The model assumes that in non-crystalline semiconductors the potential barriers exist, which separate certain microscopic areas from each other, assuming barriers possess a parabolic profile. This conception explains the rise of exponential tails of optical absorption at the end of optical edge as well as electroabsorption, photoelectric conductivity, photoluminescence, and others. Using this model, many electric transport properties of non-crystalline semiconductors can be explained successfully.
Solutions of the Schrödinger equation for Dirac delta decorated linear potential
Authors: Uncu Haydar , Erkol Hakan , Demiralp Ersan , Beker Haluk 
Published: August 2006

Abstract
We have studied bound states of the Schrödinger equation for a linear potential together with any finite number (P) of Dirac delta functions. Forx

where 0f; 0x 1x 2x P , theσ i are arbitrary real numbers, and the potential is infinite forx
Self-adjoint differential vector-operators and matrix Hilbert spaces I
Authors: Sokolov Maksim 
Published: August 2006

Abstract
In the current work a generalization of the famous Weyl-Kodaira inversion formulas for the case of self-adjoint differential vector-operators is proved. A formula for spectral resolutions over an analytical defining set of solutions is discussed. The article is the first part of the planned two-part survey on the structural spectral theory of self-adjoint differential vector-operators in matrix Hilbert spaces.
Integral representations of unbounded operators by infinitely smooth kernels
Authors: Novitskiî Igor 
Published: August 2006

Abstract
In this paper, we prove that every unbounded linear operator satisfying the Korotkov-Weidmann characterization is unitarily equivalent to an integral operator in L
2(R), with a bounded and infinitely smooth Carleman kernel. The established unitary equivalence is implemented by explicitly definable unitary operators.
The rate of convergence for spectra of GUE and LUE matrix ensembles
Authors: Götze Friedrich , Tikhomirov Alexander 
Published: August 2006

Abstract
We obtain optimal bounds of order O(n
−1) for the rate of convergence to the semicircle law and to the Marchenko-Pastur law for the expected spectral distribution functions of random matrices from the GUE and LUE, respectively.
The geometry of Kato Grassmannians
Authors: Bojarski Bogdan , Khimshiashvili Giorgi 
Published: August 2006

Abstract
We discuss Fredholm pairs of subspaces and associated Grassmannians in a Hilbert space. Relations between several existing definitions of Fredholm pairs are established as well as some basic geometric properties of the Kato Grassmannian. It is also shown that the so-called restricted Grassmannian can be endowed with a natural Fredholm structure making it into a Fredholm Hilbert manifold.
Covariance algebra of a partial dynamical system
Authors: Kosma Kwaśniewski Bartosz 
Published: August 2006

Abstract
A pair (X, α) is a partial dynamical system if X is a compact topological space and α: Δ→ X is a continuous mapping such that Δ is open. Additionally we assume here that Δ is closed and α(Δ) is open. Such systems arise naturally while dealing with commutative C
*-dynamical systems.
In this paper we construct and investigate a universal C
*-algebra C
*(X,α) which agrees with the partial crossed product [10] in the case α is injective, and with the crossed product by a monomorphism [22] in the case α is onto.
The main method here is to use the description of maximal ideal space of a coefficient algebra, cf. [16, 18], in order to construct a larger system,
$$(\tilde X,\tilde \alpha )$$
where
$$\tilde \alpha $$
is a partial homeomorphism. Hence one may apply in extenso the partial crossed product theory [10, 13], In particular, one generalizes the notions of topological freeness and invariance of a set, which are being use afterwards to obtain the Isomorphism Theorem and the complete description of ideals of C
*(X, α).
Tunnelling time of a gaussian wave packet through two potential barriers
Authors: Petrillo Vittoria , Olkhovsky Vladislav 
Published: August 2006

Abstract
The resonant and non-resonant dynamies of a Gaussian quantum wave packet travelling through a double barrier system is studied as a function of the initial characteristics of the spectrum and of the parameters of the potential. The behaviour of the tunnelling time shows that there are situations where the Hartman effect occurs, while, when the resonances are dominant, and in particular for b>π/Δk (b being the inter-barrier distance and Δk the spectrum width), the tunnelling time becomes very large and the Hartman effect does not take place.
Radiative spectra of thermal electromagnetic noise induced by planar realistic dielectrics
Authors: Dorofeyev Illarion , Fuchs Harald , Sobakinskaya Katja 
Published: August 2006

Abstract
Spectral characteristics of stochastic fields and their spatial derivatives in various planar structures composed by lossy materials described by realistic dielectric functions are numerically calculated based on solutions to the problems of multipolar electromagnetic fields in a plane layered geometry. A displacement of the maximum of the spectral power densities for spatial derivatives of fluctuating fields to the high-frequency domain, a resonant increase in the density of states of the fluctuating fields at the frequencies of interface excitations and interference modes for the radiative part of the spectra, the influence of geometry on the density of states, and other peculiarities are found by numerical calculations and graphically demonstrated. Interpretations of the above effects are provided.
Theoretical investigation of the electronic structure of a ferroelectric SbSI cluster at a phase transition
Authors: Audzijonis Algirdas , Gaigalas Gediminas , Žigas Leonardas , Pauliukas Audrius , Žaltauskas Raimundas , Čerškus Aurimas , Narusis Jurgis 
Published: August 2006

Abstract
This paper presents the theoretical investigation of energy levels of valence bands (VB) and core levels (CL) of the ferroelectric SbSl single crystals in antiferroelectric and ferroelectric phases. Since the best approximation for the deep VB levels is a calculation by the Hartree-Fock method, the molecular model of a SbSI crystal was used for calculations. This model of the crystal was also used for calculations of the total density of states. It was found that the VB and CL of this ferroelectric semiconductor are sensitive to the small lattice distortion at the phase transition, and that an average of the total density of states, when all atoms participate in oscillations of all normal modes, are more similar to the experimental X-ray photoelectron spectra (XPS). The experimental splitting of CL obtained by XPS was compared with the theoretically calculated one by two different methods. The cluster model calculations showed that the splitting of the CL in SbSI might be caused by photoelectron emission from the atoms, which have different valence state, at the surface.
Study of solid-solution hardening in binary aluminium-based alloys
Authors: Draissia Mohamed , Debili Mohamed-Yacine 
Published: August 2006

Abstract
Solid-solution formation in binary aluminium-based alloys is due essentially to the combined effects of the size and valence of solvent and solute atoms, as expected by the four Hume-Rothery rules. The lattice parameter of aluminium in the solid solution of the sputtered Al−Fe films is [Al-a (Å)=4.052−6.6×10−3Y]. The increasing and decreasing evolution of the lattice parameter of copper [Cu-a (Å)=3.612+1.8×10−3Z] and aluminium [Al-a (Å)=4.048−1.6×10−3X] in the sputtered Al-1.8 to 92.5 at. % Cu films is a result of the difference in size between the aluminium and copper atoms. The low solubility of copper in aluminium (<1.8 at % Cu) is due to the valences of solvent and solute atoms in contrast with other sputtered films prepared under similar conditions, such as Al−Mg (20 at. % Mg), Al−Ti (27 at. % Ti), Al−Cr (5at. % Cr) and Al−Fe (5.5 at. % Fe) where the solubility is due to the difference in size.
A theoretical approach to local attenuation measurements of shear waves by MRE. Preliminary experimental results
Authors: Klinkosz Tomasz , Lewa Czesław , Madelin Guillaume , Thiaudiere Eric 
Published: August 2006

Abstract
An essential highlight of the presented method is the employment of Magnetic Resonance Elastography (MRE) for local measurements of the attenuation of elastic shear waves introduced into a biological sample. Such a measurement can be accomplished by combining the MRE method with those methods, in which collective displacement of spins is induced by external physical factors, such as variable electric field, strong magnetic field gradient or longitudinal elastic wave. A theoretical basis of the method involving external factors and results of preliminary experiments have been presented in this paper.
Contribution of superstring Z′ boson on the polarization effects in proton proton collisions
Authors: Muradov Rasul , Ahmadov Azar 
Published: August 2006

Abstract
In this work we investigate the single- and the double-spin asymmetries at the collisions of polarized protons pp → (γ
*, Z
0, Z′) + X within the scope of QCD, the electroweak interaction and superstring E
6 theory. The helicity amplitude method is used. Analytical expressions for the single- and the double-spin asymmetries are obtained and their dependence on the transverse momentum of the lepton pair is investigated at the three different values of invariant masses of the lepton pair. The pure contribution coming from the superstring Z′ boson on the single- and double- spin asymmetries has been extracted. The results obtained allow investigation of the spin structure of the proton.
On the homotopy type of (n-1)-connected (3n+1)-dimensional free chain Lie algebra
Authors: Benkhalifa Mahmoud , Abughzalah Nabilah 
Published: August 2006

Abstract
Let R be a subring ring of Q. We reserve the symbol p for the least prime which is not a unit in R; if R ⊒Q, then p=∞. Denote by DGL
nnp, n≥1, the category of (n-1)-connected np-dimensional differential graded free Lie algebras over R. In [1] D. Anick has shown that there is a reasonable concept of homotopy in the category DGL
nnp. In this work we intend to answer the following two questions: Given an object (L(V), ϖ) in DGL
n3n+2 and denote by S(L(V), ϖ) the class of objects homotopy equivalent to (L(V), ϖ). How we can characterize a free dgl to belong to S(L(V), ϖ)? Fix an object (L(V), ϖ) in DGL
n3n+2. How many homotopy equivalence classes of objects (L(W), δ) in DGL
n3n+2 such that H
*
(W, d′)≊H
*
(V, d) are there? Note that DGL
n3n+2 is a subcategory of DGL
nnp when p>3. Our tool to address this problem is the exact sequence of Whitehead associated with a free dgl.
Localization of LM
n-algebras
Authors: Chirte§ Florentina 
Published: August 2006

Abstract
The aim of this paper is to define the localization LM
n-algebra of an LM
n—algebra L with respect to a topology F on L; in Section 5 we prove that the maximal LM
n-algebra of fractions (defined in [3]) and the LM
n-algebra of fractions relative to an Λ—closed system (defined in Section 2) are LM
n-algebras of localization.
Uncertainty relations expressed by Shannon-like entropies
Authors: Majerník V. , Majerníková Eva , Shpyrko S. 
Published: August 2006

Abstract
Besides the well-known Shannon entropy, there is a set of Shannon-like entropies which have applications in statistical and quantum physics. These entropies are functions of certain parameters and converge toward Shannon entropy when these parameters approach the value 1. We describe briefly the most important Shannon-like entropies and present their graphical representations. Their graphs look almost identical, though by superimposing them it appears that they are distinct and characteristic of each Shannon-like entropy. We try to formulate the alternative entropic uncertainty relations by means of the Shannon-like entropies and show that all of them equally well express the uncertainty principle of quantum physics.
Mechanism of Cu transport along clean Si surfaces
Authors: Dolbak A. , Zhachuk R. , Olshanetsky B. 
Published: August 2006

Abstract
Cu diffusion along clean Si(111), (110) and (100) surfaces are investigated by Auger electron spectroscopy and low energy electron diffraction. The effective diffusion coefficients of copper are measured in the temperature range from 500 to 650°C. It is shown that the Cu transport along silicon surface occurs by the diffusion of Cu atoms through Si bulk and the segregation of Cu atoms to the surface during the diffusion process. It is found that the segregation coefficients of Cu to silicon surface during the diffusion process depend on surface orientation.
On applicability of Gibbs thermodynamics to nanoparticles
Authors: Samsonov V. , Bazulev A. , Sdobnyakov N. 
Published: August 2006

Abstract
The problem of applicability of thermodynamics to small objects has been investigated. It is shown that the Gibbs surface phase method may be extended to nanoparticles if the effective surface tension (the specific excess free energy) is interpreted as a function of the particle radius.
Theoretical and experimental investigation of the photoacoustic effect in solids with residual stresses
Authors: Muratikov K. , Glazov A. 
Published: August 2006

Abstract
Modern experiment and theory in the field of residual stress detection by the photoacoustic method are summarized and analyzed. A multimode approach based on the simultaneous application of several photothermal and photoacoustic methods is proposed for the study of thermal and thermoelastic effects in solids with residual stress. Some experimental results obtained within the framework of this approach for Vickers indentation zones in ceramics are presented. The effect of annealing on the photoacoustic, piezoelectric signal for ceramics and the influence of the given external loading on the behavior of the photoacoustic signal near the radial crack tips is investigated. It is experimentally shown that both compressive and shear stresses contribute to the photoacoustic signal near the radial crack tips. The model of the photoacoustic, thermoelastic effect in solids with residual stress is proposed. It is based on the modified Murnaghan model of non-linear elastic bodies, which takes into account a possible dependence of the thermoelastic constant on stress. This model is further developed to explain the photoacoustic signal behavior near the radial crack tips. It is demonstrated that this model of the photoacoustic effect agrees qualitatively with the available experimental data.
An introduction to physical theory of molecular evolution
Authors: Luque Bartolo 
Published: August 2006

Abstract
This work is a tutorial in Molecular Evolution from the point of view of Physics. We discuss Eigen's model, a link between evolutionary theory and physics. We will begin by assuming the existence of (marco) molecules or replicators with the template property, that is, the capacity to self-replicate. According to this assumption, information will be randomly generated and destroyed by mutations in the code (i.e., errors in the copying process) and new bits of information will be fixed (made stable) by the existence of an external pressure on the system (i.e., selection), and the ability of the molecules to replicate themselves. Our aim is to build a model in order to describe molecular evolution from as general a standpoint as possible. As we will see, even very simple models from the theoretical point of view will have surprisingly deep consequences.
The dynamics of multiparticle collisions in motion of a granular material
Authors: Leszczyński Jacek 
Published: August 2006

AbstractWe consider the complex problem of how to calculate particle motions taking into account multiparticle collisions. Multiparticle contacts occur when a particle collides with neighbouring particles, so that those contacts have a direct influence on each other. We will focus on the molecular dynamics method. Particularly, we will analyse what happens in cohesive materials during multiparticle contacts. We investigated the expression of repulsive force formulated under fractional calculus which is able to control dynamically the transfer and dissipation of energy in granular media. Such approach allows to perform simulations of arbitrary multiparticle collisions and also granular cohesion dynamics.
Surface morphology of PrBa2Cu3O7-δ single crystals after the long-lasting high-temperature reduction
Authors: Łuszczek Maciej , Sadowski Wojciech 
Published: August 2006

AbstractThe results of the detailed scanning electron microscopy study of PrBa2Cu3O7-δ single crystals after the long-lasting high-temperature post-growth treatment are reported. The presence of the unstable decomposition products on the crystal surface indicates that the onset of superconductivity must be related to the structural transformations in the bulk (approximately 20% of the total volume of the examined crystals). The time-dependent character of the superconductivity in the Pr-123 crystals could be attributed to the migration of defects in the Pr−Ba sublattice from the bulk toward the surface.
Centrifugal (centripetal) and Coriolis' velocities and accelerations in $$ (\bar L_n ,g) $$ -spaces
Authors: Manoff Sawa 
Published: August 2006

AbstractThe notions of centrifugal (centripetal) and Coriolis' velocities and accelerations are introduced and considered in spaces with affine connections and metrics [ $$ (\bar L_n ,g) $$ -spaces] as velocities and accelerations of flows of mass elements (particles) moving in space-time. It is shown that these types of velocities and accelerations are generated by the relative motions between the mass elements. They are closely related to the kinematic characteristics of the relative velocity and relative acceleration. The centrifugal (centripetal) velocity is found to be in connection with the Hubble law. The centrifugal (centripetal) acceleration could be interpreted as gravitational acceleration as has been done in the Einstein theory of gravitation. This fact could be used as a basis for workingout new gravitational theories in spaces with affine connections and metrics.
On entanglement distillation and quantum error correction for unknown states and channels
Authors: Horodecki Pawel 
Published: August 2006

AbstractWe consider the problem of invariance of distillable entanglement D and quantum capacities Q under erasure of information about single copy of quantum state or channel respectively. We argue that any 2 ⊗N two-way distillable state is still two-way distillable after erasure of single copy information. For some known distillation protocols the obtained two-way distillation rate is the same as if Alice and Bob knew the state from the very beginning. The isomorphism between quantum states and quantum channels is also investigated. In particular it is pointed out that any transmission rate down the channel is equal to distillation rate with formal LOCC-like superoperator that uses in general nonphysical Alice actions. This allows to we prove that if given channel Λ has nonzero capacity (Q → or Q ⟺) then the corresponding quantum state ϱ(Λ) has nonzero distillable entanglement (D → or D ⟺). Follwoing the latter arguments are provided that any channel mapping single qubit into N level system allows for reliable two-way transmission after erasure of information about single copy. Some open problems are discussed.