Equipment for complex tuning and calibration of instruments for the measurement of the time characteristics of optical pulses

Equipment for complex tuning and calibration of instruments used in the measurement of the time characteristics of optical pulse radiation in the nano- and pico-second range is described. Results of calibration of an optoelectronic camera with scanning rates in the range (1.1–9.6)·10⁶ m/sec are presented.     

The effect of support roughness on adsorption activity of micro- and nanosize chitosan films

The method of quartz-crystal microbalance was used to study the process of adsorption of water vapors in chitosan films formed on a solid support with a film thickness of 5 nm to 4 μm. It is found that the adsorption capacity of thin chitosan films with a thickness that is commensurable to the roughness of the support increases at a decrease in the thickness. The kinetics of desorption in chitosan films is also determined by the ratio of film thickness and support roughness: the desorption rate constant grows when the film thickness approaches the roughness of the support (nanosize range).     

On electrocontact oxidation of iron nanocondensates

The transformation (under the effect of current passed) of a nanostructured metal-oxide coating produced by vacuum deposition of iron in an oxygen atmosphere at a pressure of 10⁻⁴ mm Hg on an amorphous glass substrate is studied by measuring voltammetric characteristics. In the freshly deposited film, a linear characteristic is observed that may correspond to direct quantum mechanical tunneling in thin oxide interlayers between metal nanograins. With an increase in the applied current density, when a certain threshold is reached, the conductivity of the conductor rapidly drops because of the thermo- and electrooxidation. In a degraded conductor at a prethreshold current density, a nonlinear voltammetric characteristic is observed, which may be related to the change in the mechanism of current flow restricted by the volume charge, as well as to the negative temperature resistance coefficient typical of fine-crystalline granular nanocomposites.     

Simulation of scattering processes of optical radiation by nanodimensional structures

Mathematical simulation of the process of scattering of an optical wave by micro- or nano-scale structure on the basis of the vector equations of the electromagnetic field is performed. A rigorous analytic solution is obtained and the scattering problem solved by means of the method of finite elements.     

Formation of nanoporous anodic films on pure aluminum in sulfuric acid

The effect of the duration of electrochemical anodic oxidation on the formation of nanoporous anodic oxide films on high-purity aluminum (99.99%) in a sulfuric acid solution is studied. The resulting oxide film is analyzed using an atomic force microscope. The method of photoelectric polarization (PEP) and X-ray analysis revealed that these films are sesquioxides of aluminum with variable compositions, nonstoichiometry due to a metal deficiency, and p-type conductivity. The mechanism of the formation of a regular nanoporous oxide structure that results from the nonstoichiometry relation and the intrinsic formation of defects in the oxide is proposed.