Nontrivial manifestation of clustering in fission of heavy nuclei at low and middle excitations

An analysis of the preferable fission path manifesting itself as a fine structure of the total kinetic energy-mass distribution of the fission fragments compelled us to put forward an absolutely new shape of the fissioning system on the descent from the fission barrier. It is a multicomponent nuclear molecule constituted by two magic clusters and a torus-like neck between.     

Associated φΛ0 production in the EXCHARM experiment

The features of the associated production of φ mesons with Λ⁰ hyperons in neutron-carbon interactions were investigated. The experiment was performed with the aid of the EXCHARM spectrometer at the Serpukhov accelerator in a neutron beam of energy in the interval 20–70 GeV. The differential cross section for inclusive associated φΛ⁰ production was measured.     

Exchange interaction and spin dynamics in pentanuclear clusters, Cu3Ln2(ClCH2COO)12(H2O)8 (Ln = Nd3+, Sm3+, Pr3+)

New compounds, [Cu₃Ln₂(ClCH₂COO)₁₂(H₂O)₈]·2H₂O with Ln = Nd³⁺ (I), Sm³⁺ (II), Pr³⁺ (III), built up of pentanuclear clusters were synthesized and studied by means of X-ray analysis and electron paramagnetic resonance (EPR). X-ray data show that all compounds are isostructural and the pentanuclear clusteres may be considered as a linear system with alternating Cu(II) and Ln(III) ions: Cu(2)-L¹-Ln-L²-Cu(1)-L²-Ln-L²-Cu(2) with L¹ and L² being bridging fragments and Cu(1) and Cu(2) being structurally nonequivalent copper complexes. EPR studies demonstrate that in the temperature range of 100–293 K the signals due to only one type of the copper complexes are observed in the spectra of I–III. AtT<100 K the spectral temperature dependence is nontrivial. AtT<30 K new signals are detected in the spectra of I and II. The temperature dependence of the EPR spectra is interpreted under the assumption that the parameter of the exchange interaction Cu(2)-Ln considerably exceeds the parameter of the interaction Cu(1)-Ln. EPR spectra are calculated for the fragments of five paramagnetic centers in the frames of the model taking into account the nonequivalence of two copper complexes, short longitudinal and transverse paramagnetic relaxation times of the rare-earth ions at room temperature and the change of the relaxation rates when the temperature decreases. The results of the calculations show that it is possible to obtain information about the interactions in the system on the basis of the analysis of the temperature dependence of the EPR spectra of the central copper complex. The parameter of the isotropic part of the exchange interaction between copper and neodymium ions (for the interaction Cu(2)-Nd) is estimated as about 15 cm⁻¹. A considerable rearrangement of the spin states when the temperature changes is found for all complexes.     

<Emphasis FontCategory="NonProportional">L</Emphasis>-Matrices and solvability of linear complementarity problems by a linear program-Matrices and solvability of linear complementarity problems by a linear program

The classes ofL ₁-matrices,L ₂-matrices,L ₃-matrices andW-matrices are introduced to study solvability of a linear complementarity problem via solving a linear program. Three sufficient conditions are presented to guarantee that a linear complementarity problem is solvable via a linear program. The new sufficient conditions are weaker than the ones introduced by Mangasarian. This fact is also illustrated by an example. Partially supported by NSFC. This author is also with College of Business Administration of Human University as a Lotus chair professor.     

Influence of Preparation Conditions on Properties of a Copper-Containing Catalyst for Electrocatalytic Oxidation of Acetone

Stages of synthesis of a copper-containing catalyst for electrocatalytic oxidation of acetone in waste gases were studied. The course of the extrusion and calcination and their influence on electrocatalytic oxidation of acetone on the catalyst synthesized were analyzed.     

Direct Single-Stage Conversion of Synthesis Gas to Dimethoxymethane: Influence of the Sequence of Metal Introduction into Cu, Pd-Zeolite Catalysts on the Degree of Cu and Pd Reduction and Catalyst Acidity

The influence of the sequence of Cu and Pd introduction into zeolite matrice when preparing Cu, Pd-zeolite catalysts on their acidity and degree of metal reduction was studied. The mutual influence of Cu and Pd on their reducibility was analyzed. The selectivity of Cu, Pd-zeolite catalysts in conversion of synthesis gas to different products was elucidated.     

Crystallographic report: Crystal structure of tetra(4‐methyl‐5‐imidazole‐carboxyaldehyde)zinc(II) diperchlorate

The central zinc(II) atom in the title complex is tetrahedrally coordinated by four nitrogen atoms derived from 4‐methyl‐5‐imidazolecarboxyaldehyde ligands with Zn? N in the range 2.007(3) to 2.026(4) Å. Copyright © 2003 John Wiley & Sons, Ltd.     

Crystallographic report: Crystal structure of a one‐dimensional zinc(II) coordination polymer containing 4,4′‐biphenyldicarboxylate hemihydrate

A one‐dimensional zinc(II) coordination polymer has been constructed from zinc(II), 4,4′‐biphenyldicarboxylate and pyridine in which each zinc(II) atom is coordinated by two pyridine ligands and two monodentate 4,4′‐biphenyldicarboxylate ligands that define a distorted tetrahedral geometry. Copyright © 2003 John Wiley & Sons, Ltd.