Effect of small total pulse on development of a wake behind the self-propelled bodies

Experimental studies on the wakes behind the self-propelled bodies of revolution have been analysed, and results of stereometric studies on the co-current flows behind autonomous streamlined and bluff bodies of revolution are presented for the times of their development corresponding to the coordinate system of a distant wake of 2400 and 1200 body diameters, correspondingly. Possible modelling of axisymmetric co-currents by the flows generated by a string at its pulse motion along the axis is examined. It is shown that supposed solutions based on the model of interferential development of wakes behind the self-propelled bodies of revolution can approximate both the known results of experimental studies of wakes behind the self-propelled bodies of revolution and the flows generated by corresponding pulse transportation of a string.     

Distribution of cations in magnetite prepared by mechanochemical synthesis

The distribution of iron cations in the crystal lattice of the Fe_3?vO₄ (v=0.153) cation-deficient spinel produced by mechanical dispersion of α-Fe₂O₃ hematite in water is investigated using x-ray diffraction and Mössbauer spectroscopy. Analysis of the Mössbauer data shows that the Fe_2.847O₄ magnetite prepared by mechanochemical synthesis is a chemically heterogeneous compound. The crystal structure of Fe_2.847O₄ is characterized by local environments of the (Fe^2.5+)₀ cations at v₀≤0.1, v₁?0.12, v₂?0.18, and v₃?0.26, which are responsible for a broad distribution of magnetic hyperfine fields with the P(H) probability maxima near 37.0, 36.0, 34.0, and 30.0 MA m^?1.     

Solution calorimetry of organic nonelectrolytes as a tool for investigation of intermolecular interactions

The paper is mainly the review and generalization of the previous publications of the authors. It demonstrates that solution calorimetry method gives the opportunities of more detailed understanding of various aspects of intermolecular interactions in solution. We are assured that prerequisite to such an understanding is the successive analysis of various solute–solvent systems from the simplest ones which include alkanes as a solute or as a solvent to the most complex systems with solvent self‐association via hydrogen bonding. Particular findings discussed in this paper are (i) an inconspicuous contribution of electrostatic solute–solvent interaction to the solvation enthalpy and, accordingly, the dominating contribution of dispersion interactions for nonspecifically solvated solutes; (ii) new, very general method for the extraction of specific interaction enthalpy from the enthalpy of solvation; (iii) new method of determination of self‐association enthalpies for the solvents associated via hydrogen bonding; (iv) new method for determination of cooperative hydrogen bonding enthalpies of proton acceptors with associated species of alcohols; (v) the unique method of experimental determination of the hydrophobic effect enthalpy. Copyright © 2007 John Wiley & Sons, Ltd.     

Eigenwave asymptotics for smoothly irregular plane anisotropic waveguide

An extension of method of horizontal rays and vertical modes developed for underwater acoustics to the spatially inhomogeneous anisotropic electrodynamic problem is proposed.Leningrad State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 34, No. 7, 790–797, July, 1991.     

Fluctuation forces in a three-layer medium with rough boundaries. III. Aspects of perturbation theory in the Casimir range

The problem of calculating the Casimir force that acts in a system of two metallic plates with rough boundaries separated by an insulating layer is considered. An algorithm for constructing a perturbation series in the small function of the roughness profile is developed.Scientific Council on the Problem Complex Kibernetika, USSR Academy of Sciences. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 91, No. 3, pp. 474–482, June, 1992.     

Untersuchungen zur Katalyse der Ammoniaksynthese und des Stickstoffisotopenaustausches durch Schichtverbindungen von Graphit mit Eisen,Ruthenium und Osmium

Investigations on the Catalysis of Ammonia Synthesis and Nitrogen Isotope Exchange by Lamellar Compounds of Graphite with Iron, Ruthenium, and Osmium The catalytic activity of transition metal potassium-graphite lamellar compounds for the synthesis of ammonia from the elements and the catalysis of the equilibration by isotope exchange of the isotopic nitrogen molecules are shown to correlate. Connections between the state of metal in the catalyst exist with iron as metal which is shown by Mössbauer spectroscopy and the catalytic activity in relation to the potassium content.