Non-monotonic exposure dependence of the pretilt angle and surface polarity of the photo-orientant F-PVCN

We report on the first observation of a non-monotonic UV exposure dependence of the pretilt angle of a liquid crystal on a photoaligning surface. We found this non-monotonic dependence on fluorinated poly(vinyl cinnamate) (PVCN-F) surface while non-fluorinated PVCN revealed a monotonic decrease of the pretilt angle with exposure. These dependences correlate with light-induced changes of the polarity of PVCN-F and PVCN surfaces. The obtained data point to an important role of the surface polarity and the light-induced changes in mechanisms of pretilt angle generation on photoaligning materials.     

A voltamperometric study of the adsorption of nitroalkanes on graphite

Conclusions It has been shown that there is a correlation between the volt-ampere characteristics of nitroalkanes adsorbed on graphite and the values of the thermodynamic parameters calculated from the adsorption isotherm.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 538–541, March, 1978.     

Non-monotonic exposure dependence of the pretilt angle and surface polarity of the photo-orientant F-PVCN

We report on the first observation of a non-monotonic UV exposure dependence of the pretilt angle of a liquid crystal on a photoaligning surface. We found this non-monotonic dependence on fluorinated poly(vinyl cinnamate) (PVCN-F) surface while non-fluorinated PVCN revealed a monotonic decrease of the pretilt angle with exposure. These dependences correlate with light-induced changes of the polarity of PVCN-F and PVCN surfaces. The obtained data point to an important role of the surface polarity and the light-induced changes in mechanisms of pretilt angle generation on photoaligning materials.     

Synthesis of 6H-SiC single-crystal nanowires in a flow of carbon-silicon high-frequency arc plasma

Silicon carbide 6H-SiC nanoparticles and nanowires were obtained in carbon-silicon high-frequency arc plasma plasma in a helium atmosphere at a pressure of 0.1–0.6 MPa. It was shown that 6H-SiC nanowires grow from the arc plasma, as well as from the vapor, according to the known mechanism of vapor-solid condensation on a cold surface covered with single-crystal silicon carbide nuclei. The content of silicon carbide nanowires in the condensate reached 60 wt %. The obtained single-crystal silicon 6H-SiC nanowires had the diameter of 15–18 nm and length of 200–600 nm.     

Solution of a class of three-dimensional boundary value problems of the theory of heat conduction

We consider a class of connected three-dimensional boundary-value problems for the quasi-linear heat equation that model the temperature fields in molds under a continuous cyclic molding of flat castings. We propose a method of approximate solution. The results of the computations are shown as the dependence of the dimensionless temperature on the time throughout ten cycles.Translated fromVychislitel'naya i Prikladnaya Matematika, Issue 71, 1990, pp. 84–90.     

Nonreciprocal properties of layered gyrotropic waveguiding structures

Radiophysics and Quantum Electronics -     

The influence of polarization of the sorbent on sorption of albumin by carbon fibers

The sorption of bovine serum albumin (BSA) on non-charged and polarized surfaces of carbon fibers (ACF) and carbon fibers modified with titanium hydroxide (ACF-Ti) was studied. It was shown that cathodic polarization considerably influences the reversibility of the BSA sorption and decreases the BSA sorption by ACF and ACF-Ti to a larger extent than anodic polarization. A change in the surface charge mainly influences sorption of albumin by ACF-Ti, which is due to different surface properties of the initial and titaniumcontaining adsorbents. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1496–1498, August, 1998.     

Effect of electrode material on impedance spectra of metal-polyethylene structures with carbon nanotubes

The effect of an electrode material on electrical properties of a composite material based on super-high-molecular polyethylene (SHMPE) filled with carbon nanotubes has been studied using impedance spectroscopy. Using the method of replacing the sample by an equivalent electric circuit, it has been found that, depending on the electrode material, a blocking barrier with high active resistance and a space charge region adjacent to it arise in the interface region. It has been shown that the barrier height is controlled by surface electronic states of SHMPE and weakly depends on the electron work function of metal electrodes (Bardeen barrier). The characteristic times of electrical relaxation characterizing bulk and interface regions of the composite under study have been determined.