Thermal properties of fluoride glasses and their gel precursors

Xerogels were prepared from zirconium, barium, aluminum, lanthanum and lithium acetates, corresponding to a Li containing ZBLA composition. The study of their thermal properties (DSC, TG/DTG, FT-IR) showed that they might be used as chemically stable precursors in the preparation of fluoride glasses. Hydrofluoric acid in solution was chosen as a mild fluorinating agent. This newly proposed technique of fluorinating allowed to obtain high quality ZBLALi glass which presents the advantage of higher thermal stability and homogeneity in comparison with the glass obtained using individual commercial fluorides.This revised version was published online in November 2005 with corrections to the Cover Date.     

Dilepton rapidity distribution in the Drell-Yan process at next-to-next-to-leading order in QCD

We compute the rapidity distribution of the virtual photon produced in the Drell-Yan process through next-to-next-to-leading order in perturbative QCD. We introduce a powerful new method for calculating differential distributions in hard scattering processes. This method is based upon a generalization of the optical theorem; it allows the integration-by-parts technology developed for multiloop diagrams to be applied to noninclusive phase-space integrals, and permits a high degree of automation. We apply our results to the analysis of fixed-target experiments.     

SIMS study of the processes in buffer solutions of bioorganic systems

Enzymatic glucose oxidation in a system modeling a glucose biosensor have been investigated by SIMS with the use of a liquid matrix. The effect of some solution parameters on the reaction product (gluconic acid) yield has been analyzed. It is shown by an example of gluconolactone hydrolysis that SIMS makes it possible to study not only final but also intermediate stage of the glucose oxidation reaction.     

Hot-electron-driven enhancement of spin-lattice coupling in Gd and Tb 4f ferromagnets observed by femtosecond x-ray magnetic circular dichroism

Femtosecond x-ray magnetic circular dichroism was used to study the time-dependent magnetic moment of 4f electrons in the ferromagnets Gd and Tb, which are known for their different spin-lattice coupling. We observe a two-step demagnetization with an ultrafast demagnetization time of 750 fs identical for both systems and slower times which differ sizeably with 40 ps for Gd and 8 ps for Tb. We conclude that spin-lattice coupling in the electronically excited state is enhanced up to 50 times compared to equilibrium.     

Top quark spin correlations at the Tevatron and the LHC

Spin correlations of top quarks produced in hadron collisions have not been observed experimentally with large significance. In this Letter, we propose a new variable that may enable demonstration of the existence of spin correlations with 3–4 σ$3\text{–}4\sigma$ significance using just a few hundred dilepton events both at the Tevatron and the LHC. Such number of dilepton events has been observed at the Tevatron. At the LHC, it will become available once integrated luminosity of a few hundred inverse picobarns is collected.     

Punctual Copies of Algebraic Structures

Siberian Mathematical Journal - We estimate the complexity of constructing a punctual “online” copy of an algebraic structure. We establish a general upper bound as well as optimal...     

Reconstruction of Three-Dimensional Maps Based on Closed-Form Solutions of the Variational Problem of Multisensor Data Registration

Doklady Mathematics - A closed-form solution is proposed for the problem of minimizing a functional consisting of two terms measuring mean-square distances for visually associated characteristic...     

Transport Models for Plasma Heating with Second Harmonic of Electron-Cyclotron Frequency

Physics of Atomic Nuclei - The optical thickness of plasma is often insufficient to absorb completely electromagnetic waves when heated at the second harmonic of the electron-cyclotron frequency....     

Dispersion characteristics of hollow-core photonic crystal fibers

This work is devoted to the study of hollow-core photonic crystal fibers (HCPCF) dispersion properties. An effective scheme of HCPCF eigenmodes analysis, lying in separate dispersion diagrams calculation for the cladding and for the HCPCF itself, was proposed. General recommendations concerning selection of proper fiber parameters were given. The text was submitted by the authors in English.