The influence of Ni(II) ion on the properties of NiO?Al2O3 catalyst prepared by impregnation method

The behavior of the NiO? Al₂O₃ catalysts is strongly dependent on the preparation method and pretreatment conditions. In the present work, we investigate the influence of Ni(II) content and various treatment temperatures on the properties of NiO? Al₂O₃ catalysts prepared by impregnation method. On the basis of experimental diffuse reflectance spectroscopy data of electronic d–d transitions of Ni(II) promoter ion, the energies of electronic states in spinel‐like structure were calculated and the most probable scheme of molecular orbital have been proposed. The results of studying the system model allowed the conclusion that the type of contact between the starting phases has a decisive influence on the coordination of Ni(II) ions. Copyright © 2010 John Wiley & Sons, Ltd.     

On isometries of matrix spaces

Let A _kbe the group of isometries of the space of n-by-n matrices over reals (resp. complexes, quaternions) with respect to the Ky Fan k-norm (see the Introduction for the definitions). Let Γ⁰ be the group of transformations of this space consisting of all products of left and right multiplications by the elements of SO(n)(resp. U(n), Sp(n)). It is shown that, except for three particular casesA_k coincides with the normalizer of Γ in Δ group of isometries of the above matrix space with respect to the standard inner product. We also give an alternative treatment of the case D = R n = 4k = 2 which was studied in detail by Johnson, Laffey, and Li [4].     

Bubble clustering and trapping in large vortices. Part 2: Time-dependent trapping conditions

In turbulent, periodically excited jets, interactions between bubbles and large coherent vortices are quantitatively studied. Simultaneous, two-phase PIV (particle image velocimetry) and photographic recordings were applied for tracking the large vortices and bubble structures and for investigating trapping phenomena. In order to quantify the interaction between bubbles and the large vortices that are formed in the shear layer, characteristic phase-averaged quantities were determined by PIV. The time-dependent vortex radius, the vorticity at the vortex centre and the time-dependent trapping conditions, obtained from the simulation of the vortex development, were tested against the experimental data.     

Relations between the half turns of the hyperbolic plane

Let R_a denote the half turn about the point a of the hyperbolic plane H. If the points a, b, c, d lie on the same line and the pair (c, d) is obtained from the pair (a, b) by a translation, then we have R_aR_b = R_cR_d. We study the group G whose generating set is {R_a:a∈H} and whose defining relations are the ones mentioned above together with the relations R²_a = 1. We show that G can be made into a Lie group, G has two connected components, and its identity component G₀ is the universal covering group of PSL₂(R). In particular, it follows that all relations between the half turns in PSL₂(R) follow from the abovementioned relations and a single additional relation of length five.     

Production of fragments withA≧16 in interactions of 6.3 GeV deuterons with Th,Bi, Au,and Ag

Polycarbonate track detector Makrofol, sensitive to fragments withA16 was used to register products of interactions of 6.3 GeV deuterons with Th, Bi, Au, and Ag. Cross sections for the production of events with one, two and three fragments have been determined and their variation as a function of theZ ²/A of the target analyzed. Possible mechanisms were proposed and discussed. Geometric characteristics of binary events were used in order to identify those binary events which resulted from the process of fission. The results were compared with corresponding proton data.We are grateful to Profs. A. M. Baldin and I. N. Semenyuskin for the exposure of the detectors and for measurement of the flux. We are also thankful to the technical staff of our Laboratory for accurate measurements.     

Determination of the D2O Content in Water by Infrared Spectrometry

A method for determining deuterium oxide content in the concentration range of 1 to 100% with a precision of 1 to 0.1 percentage unit is described. Measurements were made with a glass cell 0.6 mm thick using the infrared spectrum region from 4000 to 4400 cm^?1. It was found that glass windows can be also used for absorption cells in the range between 2300 and 3800 cm^?1 in which very intense OD and OH bands appear.     

A Polarographic Study of Chlorogenic Acid and Its Interaction with Some Heavy Metal Ions

The behavior of chlorogenic acid (CGA) and its interaction with Hg(II), Pb(II), Cu(II), Cd(II) and Zn(II) has been studied using direct current (DC) and differential‐pulse polarography (DPP). Adsorptive and kinetic/catalytic anodic waves of CGA have been detected at ?0.02 and ?0.18 V vs. SCE, respectively; Hg(I)‐CGA surface disproportionation has been assumed. Reduction of Hg(II)‐ions, added in the buffered solution of CGA (pH 7.5), occurs rather than complexation, while the complex forming ability of CGA towards Pb(II) and Cu(II) has been observed. Stoichiometry 1 : 1 for Pb(II)‐CGA, and 1 : 1 and 1 : 2 for Cu(II)‐CGA has been established applying Job’s method of continuous variation on DPP data. UV‐vis spectrophotometric measurements additionally confirmed the existence and stoichiometry of Cu(II) complexes.