Inequalities and strong laws of large numbers for random allocations

Summary Moment inqualities and strong laws of large numbers are proved for random allocations of balls into boxes. Random broken lines and random step lines are constructed using partial sums of i.i.d. random variables that are modified by random allocations. Functional limit theorems for such random processes are obtained.     

Temperature effect on the 13C NMR chemical shift of pressurized CO2 containing selected modifiers

Temperature dependence of 13C NMR chemical shift of pressurized CO2 containing modifiers has been studied. Benzene, C6F6, C6F5OH, (CF3)2CHOH and [(CH3)2N]3PO were used as the modifiers. The 13C chemical shift of CO2 was found to show a different temperature dependence in the presence of selected modifiers.     

Asymptotic properties of estimators in nonlinear functional errors-in-variables with dependent error terms

Nonlinear functional errors-in-variables models with error terms satisfying mixing conditions are studied. It is pointed out that under certain conditions the least-squares estimator of regression parameters is not consistent. An alternative estimator for regression parameters is proposed. The consistency of the alternative estimator is established. Supported by the Hungarian Foundation for Scientific Research (grant No. OTKA-T19501-1996) and by the Hungarian Ministry of Culture and Education (grant No. 179-1995). Proceedings of the Seminar on Stability Problems for Stochastic Models, Hajdúszoboszló, Hungary, 1997, Part I.     

Magnetic gap and magnetization curve for a mixed valent semiconductor: A variational approach

Zeitschrift für Physik B Condensed Matter - The ground state properties of the nondegenerate periodic Anderson model, which includes an external magnetic field, are studied variationally. We...     

Dynamics of impurity spin above the Kondo temperature

The dynamics of impurity spin contained by nonmagnetic host metal is investigated theoretically. The pseudofermion representation proposed byAbrikosov is applied to impurity spin. The calculations are carried out keeping only the leading logarithmic terms in any order of the perturbation theory. This approximation is adequate only above the Kondo temperature. Abrikosov's method is slightly modified to treat the spin dynamics. The real and the imaginary part of the pseudofermion self-energy is calculated. The imaginary part of the self-energy satisfies a simple relation which holds between the electron and pseudofermion self-energies. The decrease in the effective gyromagnetic factor is determined, which shows how the spin compensated state begins to form at low temperature. The first terms of the power series of the static susceptibility calculated from the pseudofermion Green function are in agreement with the results of the previous perturbative calculations given by e.g.Yosida andOkiji. The spectral function of the pseudofermion propagator is discussed in details. It has a long tail at large positive energies and satisfies the sum rule \(\int\limits_{{}^\_\infty }^\infty {d\omega \rho (\omega ) = 1} \) . The dynamic susceptibility and other physical quantities will be presented in the second part of this paper.     

Introducing HYPERMET-PC for automatic analysis of complex gamma-ray spectra

In short time activation analysis prompt gamma-activation analysis and in high rate -ray spectroscopy in general, the shape parameters for peaks and back ground usually vary, rendering spectrum evaluation codes based on a fixed shape calibration unsuitable. An interactive version of the well-known, fully automatic -ray spectrum analysis code HYPERMET has been developed in C ++ for the IBM-PC. It runs under MS-DOS, in conventional memory, and can handle up to 16k-channel spectra, recorded with CANBERRA's System 100 and AccuSpec and with ORTEC's ACE plug-in MCA cards. A Windows-like graphics environment is provided with mouse controlled pull-down menus, pop-up windows and rubber band expansion. All basic features of HYPERMET such as fully automatic peak search, nonlinear fitting of multiplets with automatically adjusted Gaussian peak widths exponential tails and a complex background function have been retained. All details of the fitting procedure are recorded in a data base, hence any fitted region can be retrieved and modified interactively, even after a fully automatic spectrum evaluation. The program also provides an output peak list in SAMPO90 format for further processing. The latter format is widely used in a number of sample analysis programs such as KAYZERO a software package fork ₀ standardization in neutron activation analysis.     

Reentrant phase transition in granular superconductors

The conditions for the appearance of a reentrant superconducting phase in granular materials are studied in mean field approximation applied to periodic models. We assume that the relevant low-lying excitation is the transfer of a Cooper pair from a grain to one of its neighbours, and neglect pair breaking. Both on-grain (U) and nearest neighbour (V) Coulomb interactions are taken into account, and the Coulomb problem is treated in Bethe-Peierls approximation. WhenV/U is not too large, reentrance is predicted ifV/U>(4+3z)^?1/2 wherez is the coordination number. This result is different from a recent criterion suggested by ?imánek, which allows reentrance only in the immediate vicinities of certain discrete values ofV/U. For strong enoughV/U, the models treated here show a transition to an ionic-salt-like charge-ordered state. Reentrant superconductivity is shown to occur also on an ionic background. In actual systems, close-packing effects partially frustrate the ionic ordering and enhance the reentrant feature.     

Short range and long range phase coherence in granular superconductors

The Josephson phase model with charging energies is studied in the Oguchi pair approximation. Allowing for the short-range fluctuations of the phase eliminates the reentrant feature predicted by some previous treatments. We find, however, a fluctuating tendency to reentrance in the sense that, for Josephson coupling strengths below the threshold value, the phase short-range-order in the disordered phase reaches its maximum at a finite temperature. We suggest that this might be the explanation of effects like the resistance minimum seen in granular Sn samples. We make detailed comparison between the de Gennes pseudospin model and various other truncation schemes for the phase Hamiltonian.     

Thermal Plasma Decomposition of Tetrachloroethylene

Tetrachloroethylene (C₂Cl₄) has been used widely as a solvent and dry cleaning agent, but was later specified as possible human carcinogen. As a result, its safe treatment became a priority. In this paper, we report on its decomposition in an atmospheric radiofrequency thermal plasma reactor. Main components of the exhaust gases were determined by Fourier transform infrared spectroscopy. We found that complete decomposition can be achieved in either oxidative or reductive conditions but not in neutral one. The solid soot product was characterised by transmission electron microscopy and specific surface area measurement. Organic compounds adsorbed on the surface of the soot were extracted by toluene and comprised, based on gas chromatography mass spectrometry, of various perchlorinated aliphatic (for example hexachlorocyclopentadiene) and aromatic compounds (like hexachlorobenzene, octachloronaphthalene or octachloroacenaphthylene). Several nitrogen containing molecules were also identified whose presence are rare during thermal plasma treatments. Further investigation of the extract by mass spectrometry revealed various higher molar mass chlorinated carbon clusters and two types of fullerenes (C₆₀ and C₇₀).