Study of Adsorption of TiO Nanoclusters on a TiS 2 Single Layer via the ab initio Random Structure Searching

The adsorption of TiO nanoclusters onto a TiS2 single layer surface is investigated via the density functional theory in combination with random structure searching algorithms. The nanoclusters are Ti—O dipoles and their orientation in the electrostatic field is induced by S atoms near the TiS2 single layer surface. The binding energy of nanoclusters with a TiS2 single layer surface is found to be 4.713 eV. Another curious observation is the creation of a nanocluster with an S–S–S–O anionic tetrahedron by Ti atoms, where the O anion is located at the maximum distance from the surface.     

Determining electrophysical characteristics of metal-oxide-semiconductor structures from the data of voltage-capacitance analysis of the depletion region of a semiconductor surface

The oxide layer in nanotransistors with metal-oxide-semiconductor (MOS) structures may be as thin as 20Å. The physical diagnostics of such structures via conventional methods of voltage-capacitance characteristics (VFCs) is impossible without taking into account the usually disregarded effects of degeneracy and dimensional quantization of the electron gas. However, as the oxide-layer thickness decreases, these effects make an increasingly substantial contribution to capacitance C of the MOS structure not only at C?C _i (where C _i is the “oxide capacitance”) but also at C < C _i . In this study, we have developed a general method for determining the principal characteristics of MOS structures from the data of analysis of the VFCs in the region of the Schottky depletion layer. The doping level, the surface potential, the semiconductor surface charge, the voltage of “flat bands,” oxide capacitance C _i , the voltage drop across the oxide, and the sign and density of the charge fixed in it can be found at an accuracy of ?0.1% within the framework of a single experiment regardless of the oxide-layer thickness and without using fitting parameters and a priori assumptions concerning the properties of the electron gas in the accumulation and inversion layers. The stages and results of the implementation of this method are demonstrated by the results of experiments performed on an n-Si-based MOS structure with a 171.2 Å-thick oxide layer.     

Solid Solutions of Rare-Earth Cuprates and Their Electrical Properties

Mixed cuprates based on La–Sm, La–Gd, Pr–Y, Pr–Nd, and Sm–Gd oxides are synthesized, and their physicochemical properties are investigated. The electrical properties of the studied cuprates are interpreted within the model of oxidation–reduction reactions.     

The pseudoeffect of the hydrogen chloride contained in the aramid fibres SVM, armos, and Rusar on their properties during prolonged storage and use

Data were obtained that indicate the elevated stability of the properties of SVM fibres during storage. The presence of even an important amount of HCl in the finished SVM fibres does not affect the subsequent performance characteristics. Rusor fibres, which have a lower HCI content, should have even more stable physicomechanical indexes during storage and use. __________ Translated from Khimicheskie Volokna, No. 6, pp. 7–9, November–December, 2006.     

Synthesis and Investigation of Solid Solutions Based on Indium Oxide in In<Subscript>2</Subscript>O<Subscript>3</Subscript>–MeO<Subscript>2</Subscript> (Me = Zr,Sn, Ti) Systems

Solid solutions in In₂O₃–MeO₂ (Me = Zr, Sn, Ti) systems based on indium oxide are synthesized by the coprecipitation method. It is found that the ultrasound treatment of the coprecipitation products reduces the degree of agglomeration of the initial particles by a factor of 3 and initiates the crystallization process of the precipitates. Nanocrystal (5–8 nm) precursor powders are obtained at 400°C. The optimal regime for sintering powders based on In₂O₃ to form a ceramic with a dense microstructure is chosen. The influence of the temperature, alloying additives, and the partial pressure of oxygen on the specific conductivity of indium oxide solid solutions is studied.     

Electroconducting ceramics based on In<Subscript>2</Subscript>O<Subscript>3</Subscript>, CdO,and LaCrO<Subscript>3</Subscript>

The possibility of fabricating electroconducting (10¹–10⁴ S cm^–1) ceramics based on In₂O₃, CdO, and LaCrO₃ by liquid-phase synthesis methods has been demonstrated. The results of studies of the effect of temperature, dopants, and partial oxygen pressure on the specific electroconductivity of ceramic composites are presented.     

Luminescence properties of uranyl in POCl<Subscript>3</Subscript>-SnCl<Subscript>4</Subscript> solvent

The spectral-luminescence properties of uranyl in aprotic binary solvent POCl₃-SnCl₄ were studied. The uranyl luminescence lifetime τ in the POCl₃-SnCl₄-²³⁵UO ₂ ²⁺ system does not exceed 20 μs. There is no concentration quenching of uranyl up to [UO ₂ ²⁺ ] = 0.14 M. When anhydrous UO₃ is dissolved, τ increases with increasing water content of the initial solvent,. In the solutions containing uranyl perchlorate, τ decreases with increasing uranyl and SnCl₄ concentrations. This effect is caused by products of ClO ₄ ^? decomposition scavenged by SnCl₄.     

Use of Cryogenic Treatment to Improve Profile-Bending Roll Wear Resistance

Metallurgist - The possibility of using cryogenic treatment technology for tool steel of grade Kh12VMF in preparing rolls for a profile-bending mill is analyzed. The nature of the effect of...