Huber's Minimax Approach in Distribution Classes with Bounded Variances and Subranges with Applications to Robust Detection of Signals

A brief survey of former and recent results on Huber's minimax approach in robust statistics is given. The least mformative distributions minimizing Fisher information for location over several distribution classes with upper-bounded variances and subranges are written down. These least informative distributions are qualitatively different from classical Huber's solution and have the following common structure: (i) with relatively small variances they are short-tailed, in particular normal; (ii) with relatively large variances they are heavytailed, in particular the Laplace; (iii) they are compromise with relatively moderate variances. These results allow to raise the efficiency of minimax robust procedures retaining high stability as compared to classical Huber's procedure for contaminated normal populations. In application to signal detection problems, the proposed minimax detection rule has proved to be robust and close to Huber's for heavy-tailed distributions and more efficient than Huber's for short-tailed ones both in asymptotics and on finite samples.     

Features of excitation and detection of magnetoacoustic emission in ferromagnetic objects

We study how the conditions of excitation and detection influence the magnetoacoustic emission (MAE) parameters of ferromagnets. For a large group of metal ferromagnet samples differing in physical properties and dimensions, the dependence of the MAE amplitude on the frequency of the remagnetizing field has a similar nonmonotonic character. In all probed cases, the maximum of the amplitude corresponds to a field frequency of 3–5 Hz. The decrease in the MAE amplitude for a subsequent increase in the frequency of the alternating field is related to the action of eddy currents. It is shown that the size of the field corresponding to the MAE maximum, which for a given time dependence of the remagnetizing field can be determined by the time shift in an oscillogram, can be a new parameter of the structuroscopy of ferromagnets.     

Access to 5-fluoroisoxazoles via the nitrosation of geminal bromo-fluoro arylcyclopropanes

A new method for the synthesis of 3-aryl-5-fluoroisoxazoles via the reaction of nitrosonium chlorosulfate with 2-aryl-1-bromo-1-fluorocyclopropanes containing acceptor substituents in the aromatic ring has been developed. The reaction proceeds highly regioselectively thus providing 3-aryl-5-fluoroisoxazoles in good yields. The structure of isoxazoles was corroborated by the DU8+ hybrid DFT/parametric computational approach.     

Influence of solvent electron affinity on paramagnetic defects in hybrid Si/SiOx luminescent nanoparticles

Journal of Nanoparticle Research - One-dimensional silver telluride nanowires (NWs) as potential thermoelectric materials have been studied extensively. At present, most of the efforts are focused...     

Method of Integro-Differential Relations for Optimal Beam Control

An approach to modelling and optimization of controlled dynamical systems with distributed elastic and inertial parameters are considered. The general method of integro-differential relations (IDR) for solving a wide class of boundary value problems is developed and criteria of solution quality are proposed [1]. A numerical algorithm for discrete approximation of controlled motions is worked out [2] and applied to design the optimal control low steering an elastic system to the terminal position and minimizing the given objective function [3]. The polynomial control of plane motions of a homogeneous cantilever beam is investigated. The optimal control problem of beam transportation from the initial rest position to given terminal states, in which the full mechanical energy of the system reaches its minimal value, is considered. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Study on the Kinetics of Non-isothermal Dehydration of Alkaline Earth Metal Selenites

Summary. The dehydration kinetics of crystallohydrates of beryllium, magnesium and calcium selenites were studied under non-isothermal conditions. The values of the activation energy of dehydration, the pre-exponential factor in Arrhenius equation and the change of entropy for the formation of the activated complex were calculated using the calculation procedure of Coats and Redfern. Thermal stability and activation energy of dehydration of the crystallohydrates were found to increase by the same order. The relationships observed were interpreted using Klopman’s generalized perturbation theory of chemical reactivity. The same theory was applied to explain the differences in the IR spectra of the selenite crystallohydrates studied.     

Nickel(II) bis(diphenylphosphino)amide: Redox-coupling of dppa ligands in coordination sphere of Ni and some other properties

The reactions of Ni^II[(PPh₂)₂N]₂ (2) with various reagents are described. Addition of two moles of carbon monoxide to 2, at 20 °C and atmospheric pressure leads to the redox coupling of dppa ligands and formation of zero-valent nickel complex (CO)₂Ni(Ph₂PNPPh₂PPh₂NPPh₂) (4). The nickel atom in 4 has a tetrahedral coordination and is incorporated into the NiP₄N₂ ring adopting a distorted chair conformation with phosphorus-phosphorus bond length 2.2777(5) Å. Contrary to CO, sulphur dioxide reacts with 2 to form simple adduct (SO₂)Ni^II[(PPh₂)₂N]₂. The reaction of 2 with allyl bromide runs as alkylation of dppa ligand to form All-N(PPh₂)₂NiBr₂. The reduction of 2 with metallic sodium in THF gives Ni(0) complex, HN(PPh₂)₂Ni(Ph₃P)₂ (7). The electrochemical reduction of 2 in CH₂Cl₂ takes place in two steps: reversible one-electron and quasi-reversible three-electron step.     

An EPR study of the intramolecular dynamics in o-semiquinonic nickel complexes with a diphosphorous pincer ligand

Square pyramidal o-semiquinonic nickel complexes with 2,6-bis(diphenylphosphinomethyl)phenyl have a flexible coordination sphere and exist in solution as the mixture of tautomers rapidly, according to EPR time scale, interconverting at room temperature.