Preconcentration of noble metals on a polymer support as complexes of organic reagents and their subsequent determination in the solid phase

Conditions of the sorption preconcentration of Pt, Pd, Au, Ag, and Hg as colored complexes of azorhodanines, tyrodine, and sulfonitrophenol M from acidic solutions (pH 0–2) on a polyamide membrane in the flow mode are determined. At a flow rate of 10–20 mL/min, concentrations of determined elements of 10^-9-10^-7 M, and pressure of 10–20 mm Hg, the complexes are nearly quantitatively sorbed on a polyamide membrane disk (d = 1 cm,m = 2.7 mg, andl = 0.1 mm). The influence of the composition of the test solutions on the formation of the analytical signal in the solid phase is studied. Rapid sorption-spectrometric procedures are developed for the determination of Pt, Pd, Au, Ag, and Hg with the detection limit 5–30 ng of the element in the sorbent zone     

Chiral palladium complexes with monoterpenoids oximes

Oximes of cis-caran-4-one, 3α- and 3β-hydroxycaran-4-ones, cis-verbanone, menthone, and 2β-hydroxybornan-3-one have been synthesized. The obtained oximes react with lithium tetrachloropalladate to give new chiral palladium complexes containing mono-or bidentate oxime ligands.     

Finding communities in linear time: a physics approach

We present a method that allows for the discovery of communities within graphs of arbitrary size in times that scale linearly with their size. This method avoids edge cutting and is based on notions of voltage drops across networks that are both intuitive and easy to solve regardless of the complexity of the graph involved. We additionally show how this algorithm allows for the swift discovery of the community surrounding a given node without having to extract all the communities out of a graph.Received: 29 October 2003, Published online: 14 May 2004PACS: 89.75.Fb Structures and organization in complex systems - 89.75.Hc Networks and genealogical trees     

Minimum cost spanning tree games

We consider the problem of cost allocation among users of a minimum cost spanning tree network. It is formulated as a cooperative game in characteristic function form, referred to as a minimum cost spanning tree (m.c.s.t.) game. We show that the core of a m.c.s.t. game is never empty. In fact, a point in the core can be read directly from any minimum cost spanning tree graph associated with the problem. For m.c.s.t. games with efficient coalition structures we define and construct m.c.s.t. games on the components of the structure. We show that the core and the nucleolus of the original game are the cartesian products of the cores and the nucleoli, respectively, of the induced games on the components of the efficient coalition structure.This paper is a revision of [4].     

Are the prefactor anomalies in superionic conductors due to 1-D effects?

We have examined both the ionic conductivity and the NMR line narrowing in two channel-structured superionic conductors in the light of Richards' one-dimensional theory. For Li₂Ti₃O₇ the ionic conductivity is not sufficiently anisotropic to explain the observed small NMR prefactor in terms of i-D effects. For β-LiAlSiO₄ the NMR line narrowing in the crossover region does not yield the predicted large change in the activation energy given by the 1-D theory.     

Repulsive interface forces in overlapping electric double layers in electrolyte solutions

The historical development of the problem of the electric interaction of particles in electrolyte solutions is comprehensively discussed. The existing approaches are divided into force-based methods, where the mechanical (ponderomotive) forces of the electric field are directly calculated, and energy-based methods calculating the free energy of the colloid system (at least the part of the free energy which is determined by the repulsive forces of electrical nature). The fundamental works of Langmuir, Derjaguin, Levine, Verwey and Overbeek are discussed in detail. At the same time, new original methods are proposed: the method of effective displacements; the formula of free energy of overlapping double layers.Special attention is paid to the analysis of electrostriction forces in liquids, particularly in electric double layers. The non-contradictory application of the concepts of classic macroelectrostatics is shown to result in the need to take into account electrostriction forces in overlapping double layers. The main formulas are given for force and energy of repulsion in flat surfaces with a constant density of the electric charge on them. These formulas are derived with electrostriction forces taken into account. A number of the theoretical results are new.Some experiments are discussed in measuring repulsive forces in colloid systems. A qualitative agreement is established between the experimental results of Ottewill et al. and the theory of electrostriction forces in double layers.     

Magneto-optic and luminescent properties of tellurite glass TeO<Subscript>2</Subscript>-ZnCl<Subscript>2</Subscript> doped with rare-earth elements

Tellurite glasses were synthesized on the basis of the binary system composed of 70 mol % TeO₂ and 30 mol % ZnCl₂ and doped with Nd³⁺, Pr³⁺, Tb³⁺, Er³⁺, Yb³⁺, Ho³⁺. The physicochemical, luminescent, and magneto-optic properties of these glasses were studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 8, 2004, pp. 1262–1265.Original Russian Text Copyright © 2004 by Grishin, Gurev, Intyushin, Elliev, Pavlova, Savikin.     

Dimensional Regularization and Renormalization of Non-Commutative Quantum Field Theory

Using the recently introduced parametric representation of noncommutative quantum field theory, we implement here the dimensional regularization and renormalization of the vulcanized model on the Moyal space. Submitted: June 8, 2007. Accepted: December 11, 2007.     

trans-Dichlorobis{(1R,4S)-1,7,7-trimethyl-3-[(S)-α-methylbenzylimino]bicyclo[2.2.1]heptan-2-one-N}Palladium(II): Synthesis and structural examination

A reaction of (1R,4S)-1,7,7-trimethyl-3-[(S)-α-methylbenzylimino]bicyclo[2.2.1]heptan-2-one with lithium tetrachloropalladate gave a chiral palladium(II) complex with monodentate coordination of the organic ligand. The structure of the complex was confirmed by NMR spectra and X-ray diffraction data.