Localization of light energy on the nanometer scale in a silicon cone

The spatial structure of light fields in a metallized cone filled with a medium with complex dielectric function was studied on the basis of the exact solution of the eigenwave problem. It is suggested that silicon can be used as a core of optical probe in the visible spectral region. It is shown that the density of light energy at the output of optical probe can be drastically increased if silicon is used instead of glass fiber.     

Sterically stabilized emulsion polymerization of styrene: Pseudo‐semicontinuous approach

The sterically stabilized emulsion polymerization of styrene initiated by a water‐soluble initiator at different temperatures has been investigated. The rate of polymerization (R_p) versus conversion curve shows the two non‐stationary‐rate intervals typical for the polymerization proceeding under non‐stationary‐state conditions. The shape of the R_p versus conversion curve results from two opposite effects—the increased number of particles and the decreased monomer concentration at reaction loci as the polymerization advances. At elevated temperatures the monomer emulsion equilibrates to a two‐phase or three‐phase system. The upper phase is transparent (monomer), and the lower one is blue colored, typical for microemulsion. After stirring such a multiphase system and initiation of polymerization, the initial coarse polymer emulsion was formed. The average size of monomer/polymer particles strongly decreased up to about 40% conversion and then leveled off. The initial large particles are assumed to be highly monomer‐swollen particles formed by the heteroagglomeration of unstable polymer particles and monomer droplets. The size of the “highly monomer” swollen particles continuously decreases with conversion, and they merge with the growing particles at about 40–50% conversion. The monomer droplets and/or large highly monomer‐swollen polymer particles also serve as a reservoir of monomer and emulsifier. The continuous release of nonionic (hydrophobic) emulsifier from the monomer phase increases the colloidal stability of primary particles and the number of polymer particles, that is, the particle nucleation is shifted to the higher conversion region. Variations of the square and cube of the mean droplet radius with aging time indicate that neither the coalescence nor the Ostwald ripening is the main driving force for the droplet instability. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 804–820, 2003     

Synthesis of 1,3-Bis(trialkylammonio)-2-propanol Dihalides Exhibiting Retardant Activity toward Rape

1,3-Bis(trialkylammonio)-2-propanol dihalides were prepared, and their retardant activity was studied in relation to the chemical structure.     

Spectral Analysis of Powers of the Operator (Vf)(x)=q(x)∫0 xw(t)f(t),dt

Mathematical Notes -     

Long-Term Prediction of Creep Strain of Expanded Polystyrene

Data obtained in investigating the creep of expanded polystyrene in compression are discussed. An analysis of the results of creep tests 65–608 days long showed that the creep can be predicted for 50 years based on experiments of less duration than the 605 days indicated in EN 13163. For this purpose, it is suggested to employ a 95-fold extrapolation in time if the creep curves are described by a power function (as recommended by EN 13163) or a 50-fold extrapolation if the exponential equation proposed in the present paper is used. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 6, pp. 795–802, November–December, 2005.     

Evaluation of the Degree of Cross-Linking of Epoxy-Acrylate Polymers with a Luminescence Probe

Luminophores, 4,4'-diaminodiphenylmethane and Oxazine-17, were introduced into a photopolymerizable formulation based on an epoxy-acrylate oligomer, and their behavior in thin-film polymerization was studied.     

Resonant Phenomena in Slowly Irregular Rectangular Waveguides

A waveguide with a rectangular cross section of size and orientation slowly changing along the length of the waveguide is considered. Methods of the canonical perturbation theory are used to describe the ray dynamics in the waveguide. As the size and orientation of the cross section slowly change along the ray trajectory, certain resonance conditions may be satisfied. The phenomena of scattering on resonance and capture into resonance is studied. These phenomena lead to destruction of the adiabatic invariance in the system. Bibliography: 12 titles.__________Published in Zapiski Nauchnykh Seminarov POMI, Vol. 300, 2003, pp. 173–179     

Role of the microstructure on the transport properties of Y-doped zirconia and Gd-doped ceria

Transmission electron microscopy characterizations and XPS analyses have allowed us to show the influence of the microstructure and nanochemistry on the transport properties of Y₂O₃-(9 mol%)-stabilized zirconia (YSZ) and Gd₂O₃ (10 mol%)-doped ceria (GDC). The grain boundary electrical conductivity (σ_gb) and oxygen diffusion coefficient (D_o) of conventional YSZ ceramics increase with the grain size, while an opposite behavior was found for GDC samples. This difference was attributed to glassy precipitates present at YSZ grain boundaries. Furthermore, it was shown that kinetic demixing processes take place during cooling, at the end of sintering. This causes important changes in the cationic species distribution at interfaces and plays an important role on the transport properties of these two materials. Paper presented at the 9th EuroConference on Ionics, Ixia, Rhodes, Greece, Sept. 15 – 21, 2002.