Electron-Conduction Mechanism and Specific Heat Above Transition Temperature in LaFeAsO and BaFe2As2 Superconductors

The ionization energy theory is used to calculate the evolution of the resistivity and specific heat curves with respect to different doping elements in the recently discovered superconducting pnictide materials. Electron-conduction mechanism in the pnictides above the structural transition temperature is explained unambiguously, which is also consistent with other strongly correlated materials, such as cuprates, manganites, titanates and magnetic semiconductors.     

Carbon nanotubes on nanoporous alumina: from surface mats to conformal pore filling

Control over nucleation and growth of multi-walled carbon nanotubes in the nanochannels of porous alumina membranes by several combinations of posttreatments, namely exposing the membrane top surface to atmospheric plasma jet and application of standard S1813 photoresist as an additional carbon precursor, is demonstrated. The nanotubes grown after plasma treatment nucleated inside the channels and did not form fibrous mats on the surface. Thus, the nanotube growth mode can be controlled by surface treatment and application of additional precursor, and complex nanotube-based structures can be produced for various applications. A plausible mechanism of nanotube nucleation and growth in the channels is proposed, based on the estimated depth of ion flux penetration into the channels.

PACS

63.22.Np Layered systems; 68. Surfaces and interfaces; Thin films and nanosystems (structure and non-electronic properties); 81.07.-b Nanoscale materials and structures: fabrication and characterization     

Effect of nanovolumes of additives on the properties of motor oils. Theoretical principles

A method is proposed for scattered light correlation spectroscopy for objective evaluation of the effect of water, oxidation products, and particulate contaminants on the size of colloidal formations in petroleum oils with additives. It was shown that to increase the colloidal stability — resistance to separation of oils with additives — and correspondingly improve their performance properties, it is necessary to take into account the intermolecular interactions of the additives in composites and to ensure the minimum change in them under the effect of external factors. The mechanism of the reaction of the additives and their selection for ensuring the assigned performance properties of lube oils is theoretically substantiated. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 43–45, May–June, 2008.     

Calculation of the interaction energy of the twinning dislocations of a wedge twin based on the mesoscopic dislocation model

The energy of interaction of the twinning dislocations in a wedge crystal twin was calculated based on the mesoscopic dislocation model. It has been established that the interaction energy of the twinning dislocations increases moderately with increase in the length of the twin. It is shown that the dependence of the interaction energy of the twinning dislocations on the width of the twin is near-parabolic.     

Potentiometric Determination of DP-11 Additive in Motor Oils. Improved Method

It is necessary to control the quality of motor oils, both fresh and used, the latter to determine the residual service life, to prevent engine breakdowns.     

Lubricant based on used motor oil

A lubricant is proposed-an analog of transmission oil made from exhaustively treated used motor oil with addition of a thickener and a special additive package. The results of an evaluation of its physicochemical and some performance properties are reported. VIITiN __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 35–37, July–August, 2006.     

Investigation of the Mechanical Twinning of Antimony Single Crystals by Nanoindentation

The twinning of antimony single crystals in nanoindentation has been investigated. The role of twinning in the formation of the impression of the Berkovich pyramid on the surface (111) of antimony single crystals has been established. A new method of investigation of the mechanical twinning of single crystals has been developed. For the first time, the duration of the process of twinning has been determined experimentally by a direct technique.