Intra- and inter-shell Kondo effects in carbon nanotube quantum dots

The linear response transport properties of carbon nanotube quantum dot in the strongly correlated regime are discussed. The finite-U mean field slave boson approach is used to study many-body effects. Magnetic field can rebuilt Kondo correlations, which are destroyed by the effect of spin-orbit interaction or valley mixing. Apart from the field induced revivals of SU(2) Kondo effects of different types: spin, valley or spin-valley, also more exotic phenomena appear, such as SU(3) Kondo effect. Threefold degeneracy occurs due to the effective intervalley exchange induced by short-range part of Coulomb interaction or due to the intershell mixing. In narrow gap nanotubes the full spin-orbital degeneracy might be recovered in the absence of magnetic field opening the condition for a formation of SU(4) Kondo resonance.     

Wavelet-based discrimination of isolated singularities masquerading as multifractals in detrended fluctuation analyses

Nonlinear Dynamics - The robustness of two widespread multifractal analysis methods, one based on detrended fluctuation analysis and one on wavelet leaders, is discussed in the context of...     

On the concepts of rationalizability in games

Rationalizability arises when the decision situations and rational behaviors of the players are common knowledge among them. We extend the notion of rationalizability, introduced by Bernheim [5] and Pearce [18] for Bayesian behavior, to some another kinds of player's behavior. We also present a representation of common knowledge consisting in introducing an additional player who sends messages to the players. This revised version was published online in June 2006 with corrections to the Cover Date.     

Free transverse vibration analysis of a toothed gear

Analysis of transverse vibration of the gear found in a high-speed gearbox considered as an annular plate reflecting gear geometry is the subject of this paper. How gear angular velocity affects the deformation of normal modes of transverse vibration of the system under consideration is analysed. Models considered were discretized by the finite elements method. Numerical computations have been performed in the ANSYS environment. The algorithm to identify the proper distorted mode shapes is presented. The Campbell diagram for the system under consideration is elaborated. The problems discussed here can be useful for engineers dealing with dynamics of rotating machine systems.     

Almost compatible X-microstructures in CuAlNi shape memory alloy

A systematic study of a specific martensitic microstructure, called the X-microstructure, is carried out with the focus on the CuAlNi shape memory alloy undergoing the cubic-to-orthorhombic transformation. The set of all crystallographically distinct candidate X-microstructures is determined, and it is shown that, according to the crystallographic theory of martensite, none of them is compatible. Almost compatible X-microstructures, which involve elastic strains, are thus examined. These microstructures are searched in the neighborhood of all candidate X-microstructures by minimizing the total elastic strain energy with respect to the microstructure parameters. Several low-energy X-microstructures are found, and it is shown that the total elastic strain energy correlates reasonably well with one of the indicators which characterize incompatibility of the corresponding candidate X-microstructure.     

Phosphinoyl-aziridines as a new class of chiral catalysts for enantioselective Michael addition

A series of new optically pure phosphine oxides containing chiral aziridine subunit were synthesized in good yields and applied as organocatalysts in asymmetric Michael reaction of various aliphatic aldehydes with β-nitrostyrene. The corresponding organocatalysts were synthesized starting from optically pure aziridines in a few simple efficient steps. The appropriate Michael adducts were obtained in most cases in very high chemical yield (up to 97%), excellent enantioselectivity (up to 98% of ee) and diastereoselectivity (up to 95:5 of dr).     

Fast and sensitive determination of pesticide residues in vegetables using low-pressure gas chromatography with a triple quadrupole mass spectrometer

In this study, the feasibility of low-pressure gas chromatography (LP-GC) in conjunction with a triple quadrupole mass spectrometer, as a route towards fast pesticide residue analysis, was investigated. A Varian GC-MS system equipped with a mass spectrometer model 1200 was used. LP-GC-MS experiments were performed on a HP-5 10 m x 0.32 mm x 0.25 microm analytical column connected to a 2.5 m x 0.15 mm non-coated restriction precolumn at the inlet end. For comparison purposes conventional GC-MS analysis was performed on a RTX-5 30 m x 0.25 mm x 0.5 microm column. Under the optimized conditions the analysis time was reduced to 13.3 min with the LP-GC approach which corresponds to an almost threefold gain in speed versus the conventional GC (37 min). Despite the poorer separation power of the LP-GC column, the experiments conducted with tomato and onion extracts spiked with 78 pesticides proved that LP-GC-MS is of practical value to perform full scan screening analysis. Moreover, the rate of false negative results was higher in the case of conventional GC-MS while the LP-GC-MS enabled correct identification of pesticides at lower levels since the peaks were improved in both size and shape. Validation experiments were performed on a sample of 12 representative pesticides for comparison of performance characteristics of the LP-GC and GC approaches with mass spectrometer operated in scan, SIM and MS/MS mode. The LP-GC column set-up interfaced to the MS detector was found to be superior to the conventional GC with respect to obtained linearity, accuracy and precision parameters. Also, lower limits of detection in real extracts were achieved using the LP-GC approach. Finally, the LP-GC-MS/MS analysis of tomato samples with incurred pesticide residues demonstrated the applicability of the developed method for analysis of real samples.     

Analysis of Assumptions in BIG Bell Test Experiments

Recently, a group of experiments tested local realism with random choices prepared by humans. These various tests were subject to additional assumptions, which lead to loopholes in the interpretations of almost all of the experiments. Among these assumptions are fair sampling, no signaling, and faithful reproduction of a Bell-type quantum model. The data from 9 of 13 experiments were examined and occurring anomalies were analyzed in view of the above assumptions. It is concluded that further tests of local realism need better setup calibration to avoid apparent signaling or necessity of the complicated underlying quantum model.     

Nonsmooth dynamic frictional contact of a thermoviscoelastic body

Abstract

This paper studies a system of two hemivariational inequalities modeling a dynamic thermoviscoelastic contact problem with general nonmonotone and multivalued subdifferential boundary conditions. Thermal effects are included in the Kelvin–Voigt thermoviscoelastic constitutive law and in the boundary conditions, and so in frictional heat generation, which takes place on the boundary and enters the condition for the temperature. The existence of a weak solution to the problem is established using a recent surjectivity result for differential inclusions associated with pseudomonotone operators.