Impact of dendritic interface modifiers on phase behavior of polyvinylcarbazol-CdSe/ZnS nanocomposite films

The phase behavior of mixtures of poly(9-vinylcarbazol) (PVK) and CdSe/ZnS quantum dots (QDs) were studied depending on the nature of the surfactant used as QDs shell, namely, “native surfactant” (NS) originated from the QDs synthesis, and specially designed two-component interface modifiers comprising of dendritic phosphonic acids possessing alkyl- or cyano-terminal groups and hexyl phosphonic acid as a cosurfactant. It is shown, that the nature of interface modifier dramatically influence on distribution of QDs in the nanocomposite film. Thus, both the “native surfactant” and alkyl-containing dendritic interface modifiers favors to phase segregation of QDs in the resulting nanocomposites where two-dimensional aggregates are localized near-surface layer of the PVK film. In contrast, the cyano-containing dendritic interface modifier provides the homogeneous QDs distribution through the film thickness. We determined that the concentration quenching of QDs photoluminescence is observed for PVK/QD(NS) film. For PVK films containing QDs grafted with dendritic surfactants, the luminescent intensities increase vs QD concentration up to 80–85 wt%.     

Effect of a magnetic field on the etching of steel in nitric acid solutions

The effect of a static magnetic field on the chemical etching of steel in nitric acid solutions was studied. It was demonstrated that the field substantially promotes the process of etching because of the magnetohydrodynamic intensification of mass transfer, the limiting stage of steel dissolution in nitric acid solutions.     

Dynamics of a Loss-Modulated, Two-Wave CO2 Laser Lasing on Lines of Different Vibrational Bands

The nonlinear dynamics of a loss-modulated, two-wave CO₂ laser lasing on vibrational–rotational lines of different vibrational bands has been investigated theoretically and experimentally. It is shown that the time and energy parameters of laser radiation can be controlled within fairly wide limits by changing the depth and frequency of modulation and the ratio between the constant components of the losses.     

Pathways for cyclizations of hydrazine-derived 2-(2-cyanovinyl)-3-oxo-cyclohex-1-ene enolates

The introduction of a hydrazine functionality into 2-(2-cyanovinyl)-3-oxo-cyclohex-1-ene enolates results in their spontaneous cyclizations with participation of the hydrazine moiety. Depending on the reaction conditions used, the hydrazine-derived enolates are transformed into derivatives of 1-arylpyridine-2-one-3-carbonitriles or pyrazoloquinolinones in a one-pot synthesis. They also react with anilines to give the corresponding N1-substituted pyridine-2-one-3-carboxamides. Product characterization was performed by means of spectroscopic and X-ray diffraction studies. In addition, for structure elucidation purposes, a counter synthesis of 1-arylaminopyridine-2-one-3-carboxamide was also carried out.     

Luminescence spectroscopy of the earth

The first attempt to consider global radiation luminescence fields (spheres) of the Earth has been undertaken. In general four types of luminescent fields characterize the superficial geospheres. (1) Luminescence of organic and bioorganic substances comprising the atmosphere, the hydrosphere, the lithosphere and the technosphere, being a unique distinguishing property of our planet in the Universe. (2) Recombination luminescence of key rock-forming minerals (feldspar, quartz, carbonates) that is characteristic of the granite and sedimentary layers occupying some 30% of the Earth's crust. (3) Photoluminescence of dozens of ironless minerals in so-called fluorescence anomalies formed with the help of fluids ascending along fractures and faults to the surface of the Earth. While ascending they accumulate many rare metal elements including transition ones. Entering crystal lattices of ironless mineral-dielectrics these metals form centres of luminescence. (4) Artificial luminescent materials created in the technosphere in the 20th century. The main types have origins in natural luminophors. So, in every field of application of photo-, thermo, cathodo-, electro-, X-ray-luminophors and laser crystals they have many analogues among the luminescent minerals.     

Flavonoid composition of the pollen (pollen pellets) fromSalix caprea andS. alba

Chemistry of Natural Compounds -