2,2,7,7-tetramethyl-5-homopiperazinonenitroxide,a new stable free radical

Russian Chemical Bulletin -     

Fluctuations of local optical anisotropy of island films

A method for the determination of the island film structure parameters by measuring fluctuations of optical characteristics of small areas of the film is proposed and implemented. The extinction fluctuations of the laser beam are measured experimentally in a focal spot, in which the polarization of radiation is modulated in time and which is movable over the film. From the optical data thus obtained, the optical absorption anisotropy of the nanometer-size islands of the film is evaluated. It is shown that this characteristic has a considerable frequency dispersion in the region of plasmon resonances of the nanoparticles.     

Thermal Properties of Na2O-MgO-TiO2-Al2O3-B2O3-SiO2 Glasses and Prospects for Their Use for Sealing Solid Oxide Fuel Cells

A series of Na₂O-MgO-TiO₂-Al₂O₃-B₂O₃-SiO₂ glasses promising as sealants for solid oxide fuel cells are prepared. The glassy state is confirmed by X-ray diffraction analysis, and the elemental composition is determined by inductively coupled plasma atomic emission spectroscopy. The coefficient of thermal expansion (CTE) is calculated from the dilatometric data; it varies within (69–77) × 10^?7 K^?1 and increases with the MgO to Al₂O₃ concentration ratio. The CTE calculation by the Appen method gives the results that are underestimated by 5–8% relative to the experimental data. The temperature dependences of the heat capacity of the glasses are determined by differential scanning calorimetry and calculated using the Kopp-Neumann rule. Comparison of the calculated values with the experimental data shows that the Kopp-Neumann rule is observed for the systems under consideration with relatively high accuracy. The sensitivity of different methods in determination of the glass transition point has been evaluated.