Numerical Simulation of the Motion of Aerosol Particles in Open Cell Foam Materials

Russian Journal of Physical Chemistry A - The motion of aerosol particles in open cell foam material is studied. The porous medium is investigated for a three-dimensional case with detailed...     

Triplet-triplet absorption spectra of meso-tetraphenyl-2,3-tetranaphtho-2,3-tetraphenanthroporphins

Flash photolysis has been used to measure triplet-triplet (T-T) absorption spectra of meso-tetrapheny1-2,3-tetranaphthorphin and its zinc complex, and also zinc complexes of two isomers of meso-tetrapheny1-2,3-tetraphenanthrenopurphin. An analysis has been made of the inf Iuence of structural changes on the T-T absorption spectra.Institute of Physics, Academy of Sciences of the Belorussian SSR, Minsk. Scientific-Research Institute of Organic Intermediates and Dyestuffs, Moscow. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, No. 1, pp. 105–108, January–February, 1991. Original article submitted February 24, 1989.     

Elektronen-Spin-Gitter- und Spin-Spin-Relaxation von Cu(II) in Ni(II)-bis(1,1-dicyanoäthylen-2,2-dithiolat)-Einkristallen

The temperature-dependence of the electron-spin-lattice- and -spin-spin-relaxation times T₁ and T₂ of Cu(II) in (Tetrabutyl-ammonium)-Ni(II)bis(1,1-dicyanoethylene-2,2-dithiolate) single crystals are reported. In the range of the direct processes (T = 2…7°K) a dependence of the spin-lattice relaxation rate on the orientation of the Cu-nuclear spin was observed. From the temperature-dependence of the RAMAN -process the DEBYE -temperature and the averaged soundvelocity of the molecular crystal have been derived being θ = (100 ± 10)°K and 〈v〉 ≈ 0.7. 10⁵ cm/sec. In order to explain the unusual small line-width of the ^63,65Cu-hyperfine structure lines of the EP R-spectrum in the investigated large temperature-range of T = 2.0…300°K the mechanisms contributing to the line width were analyzed. The possible influence of the strong covalency of the Cu-ligand bonds to T₁ is considered.     

Synthesis of Sodium Borohydride Dihydrate and Specific Features of Its Thermolysis

Process of thermolysis of sodium borohydride dihydrate samples produced from solution and via a vapor was considered. A study of an acetonitrile solution made by the method of nuclear magnetic resonance demonstrated that the stoichiometry is observed in both cases. An X-ray diffraction analysis evidenced that the sample produced via a vapor is defective. It was found that, in both cases, the process begins after the reaction of peritectic decomposition of the starting compound occurs and a liquid phase is formed. The enthalpy of the peritectic reaction was determined to be ΔH_react = 18.6 ± 1.5 kJ mol^?1 for the sample crystallized from an alkaline solution. For the sample produced via a vapor, this quantity is substantially smaller. The kinetics of a low-temperature thermolysis (40–80°C) of both samples is described by the Avrami—Erofeev equation.

     

Two-Magnon Relaxation Processes in Nanocrystalline Thin Magnetic Films

Russian Physics Journal - Numerical analysis of the micromagnetic model was used to reveal the ‘resonance’ feature of relaxation processes in nanocrystalline thin magnetic films. This...     

Magnetic Properties of Permalloy Thin Film Edges

Russian Physics Journal - The paper presents the results of ferromagnetic resonance (FMR) spectrometry of magnetic properties of nanocrystalline thin films obtained by magnetron sputtering of...     

Local‐Curvature‐Controlled Non‐Epitaxial Growth of Hierarchical Nanostructures

Site‐selective growth on non‐spherical seeds provides an indispensable route to hierarchical complex nanostructures that are interesting for diverse applications. However, this has only been achieved through epitaxial growth, which is restricted to crystalline materials with similar crystal structures and physicochemical properties. A non‐epitaxial growth strategy is reported for hierarchical nanostructures, where site‐selective growth is controlled by the curvature of non‐spherical seeds. This strategy is effective for site‐selective growth of silica nanorods from non‐spherical seeds of different shapes and materials, such as α‐Fe₂O₃, NaYF₄, and ZnO. This growth strategy is not limited by the stringent requirements of epitaxy and is thus a versatile general method suitable for the preparation of hierarchical nanostructures with controlled morphologies and compositions to open up a verity of applications in self‐assembly, nanorobotics, catalysis, electronics, and biotechnology.     

Catalytic Activity of Nickel and Iron Sulfides in the Degradation of Resins and Asphaltenes of High-Viscosity Oil in the Presence of Carbonate Rock Under Hydrothermal Conditions

Kinetics and Catalysis - A study was made of the laws of transformation of the composition of high-viscosity oil under hydrothermal conditions in a porous medium of carbonate rock in the presence...