Aging effect of diethanolamine derived precursor sol on TiO<Subscript>2</Subscript> films deposited at different annealing temperatures

A diethanolamine stabilized precursor sol has been utilized for studying the effect of sol aging and annealing temperature on key properties of TiO₂ films. X-ray diffraction investigations have shown increased crystallite size in the films as a function of both sol aging and the thermal treatment. Fourier transform infrared studies have elucidated that cleavage of the bond involving diethanolamine and the alkoxide in the films requires high temperature annealing treatment upon the use of aged sol for the deposition of the films. Multiple step chronoamperometry has shown the ion storage capacity of the films increases as a function of sol aging, with the highest extent of Li ion insertion being obtained for films produced from as-prepared and aged sols and subsequently annealed at, 300 and 350 °C, respectively. Films with excellent optical quality were obtained. Ellipsometry revealed that the refractive indices of the films vary from 1.67 to 2.02. The highest thickness obtained in these films was nearly 900 nm. The bandgaps of the films for both direct and indirect transitions decreased as a function of precursor sol’s aging. In addition, although the indirect bandgap values have shown a decrease with increasing annealing temperature, the direct bandgap values reveal a slight increase as a function of annealing temperature.     

Inversion of the Kirkwood–Buff theory of solutions: application to binary systems

Kirkwood–Buff (K–B) integrals play an important role in characterizing the properties and interactions of various liquid mixtures. However, there exists no method to calculate directly the K–B integrals from the easily available experimental data of ultrasonic velocity and density. An attempt has been made to evaluate the same using these initial parameters. A statistical mechanical theory advanced by Arakawa et al. has been used here, in combination with a semi-empirical formula to compute K–B parameters in the whole concentration range for six binary systems at atmospheric pressure and at 298.15 K.     

Charge shift model for calculation of electric field gradient in tetragonal closed packed metals

The electronic charge distribution in tetragonal closed packed (tcp) metal is approximated by a collection of spherical charge clouds situated midway between the ions. The anisotropy of the charge distribution is parameterized in terms of a charge shift δ derivable from the lattice parameters and the elastic coefficients of the metal. The electric field gradient (EFG) in the metal can be obtained through lattice summations over the charges. Numerical calculations are made to obtain the EFG in pure indium and indium-based dilute impurity alloys. Fairly good agreement with the experiments is achieved.     

Oxygen-assisted shape control in polyol synthesis of silver nanocrystals

We have found that the shape of silver nanocrystals is conveniently controlled by injection of oxygen gas during the polyol reduction of silver ions. The presence of oxygen effectively promotes the oxidative etching of multiple twined particles. Adjusting the flow rate of the oxygen gas yields uniformly-sized silver nanocubes, right bipyramids, nanowires, and spherical nanoparticles depending on the injection rate of the oxygen gas. Electron diffraction and high resolution TEM observations of the synthesized nanocrystals show our nanocrystals do consist of silver, not of silver oxide. SERS activities of the synthesized nanocrystals were also examined.     

Sensitivity analysis for cocoercively monotone variational inclusions and (A,η)-maximal monotonicity

Sensitivity analysis for cocoercively monotone variational inclusions based on the generalized resolvent operator technique is discussed. The notion of the cocoercive monotonicity unifies most of the existing notions, such as cocoercivity, strong monotonicity, relaxed monotonicity, relaxed cocoercivity, and others. As a result, the obtained results are general in nature.     

Mixing characterization of mechanically milled Fe75Si15M10 powders using Mössbauer spectroscopy

Iron nitrides are attractive as they show excellent magnetic properties which can be utilized as recording and permanent magnetic materials for potential applications. Due to the high saturation magnetization and chemical stability, γ ^′-Fe₄N compound is widely investigated as a promising high density magnetic recording material. γ ^′-Fe₄N particles were synthesized by conventional gaseous nitriding in a heated atmosphere containing ammonia as a source of nitrogen. X-ray diffraction, ⁵⁷Fe Mössbauer spectroscopy, vibrating sample magnetometer, scanning electron microscopy and transmission electron microscopy are used for the characterization of the as prepared sample.     

Ultra high vacuum electron spectrometer for ‘DSCEMS’

Depth Selective Conversion Electron Mössbauer Spectroscopy (DSCEMS) has become a very important surface science technique during the last one decade and attracted world wide interest specially because it gives more detailed knowledge of the properties and structure of the solid surfaces. The design and details of an ultra high vacuum cylindrical mirror analyser (CMA) for DSCEMS are described and illustrated.     

Ultrasonic and Thermophysical Properties of Cobalt Nanowires

Acoustical Physics - We have estimated elastic, mechanical, thermal and ultrasonic properties, in high temperature regime, of cobalt nanowires (Co-NWs) having a hexagonal close-packed (HCP)...