The morphology and structural properties of InP thin films deposited by spray pyrolysis method

InP film samples were prepared by spray pyrolysis technique using aqueous solutions of InCl₃ and Na₂HPO₄, which were atomized with compressed air as carrier gas onto glass substrates at 500 °C with different thicknesses of the films. The structural properties of the samples have been determined by using X-ray diffraction (XRD). It was found that the crystal structure of the InP films is polycrystalline hexagonal. The orientations for all the obtained films are along the c-axis perpendicular to the substrate. It is observed that the crystallite sizes of the films increase with the thickness of the film up to 616 nm. The changes observed in the morphology and structural phases related to the film thickness have been discussed in detail.     

Minimal numerical-radius extensions of operators

In this paper we characterize minimal numerical-radius extensions of operators from finite-dimensional subspaces and compare them with minimal operator-norm extensions. We note that in the cases , and in the case of self-adjoint extensions in , the two extensions and their norms are equal.

We also show that, in the case of , , and more generally in the case of the dual space being strictly convex, if the minimal projections with respect to the operator norm and with respect to the numerical radius have equal norms, then the operator norm is . An analogous result is also true for an arbitrary extension. Finally, we provide an example of a projection from onto a two-dimensional subspace which is minimal with respect to norm but not with respect to the numerical radius for , and we determine the minimal numerical-radius projection in this same situation.

     

Similarity Classes of 3 × 3 Matrices Over a Local Principal Ideal Ring

In this article similarity classes of three by three matrices over a local principal ideal commutative ring are analyzed. When the residue field is finite, a generating function for the number of similarity classes for all finite quotients of the ring is computed explicitly.     

Chemical effects on the L-shell X-ray fluorescence parameters of Ta and W compounds

The L shell X-ray production cross-sections, the intensity ratios_, and the average fluorescence yields of pure Ta, W and their compounds have been analysed. The targets were irradiated with γ-photons at 59.5 keV from a ²⁴¹Am annular source and detected using an Ultra-LEGe detector with resolution of 150 eV at 5.9 keV. The experimental results were compared with the other theoretical and experimental results. The obtained results were interpreted according to the chemical effect and influence of removing electrons from the shells above the L shell.     

The Mild N-Nitrosation of Secondary Amines with Trichloro Nitromethane

Reaction of trichloronitromethane with secondary amine leads to the formation of corresponding carcinogeneous N-nitrosamines under mild conditions.     

Exact solutions of nonlinear time fractional partial differential equations by sub‐equation method

In this article, the sub‐equation method is presented for finding the exact solutions of a nonlinear fractional partial differential equations. For this, the fractional complex transformation method has been used to convert fractional‐order partial differential equation to ordinary differential equation. The fractional derivatives are described in Jumarie's the modified Riemann–Liouville sense. We apply to this method for the nonlinear time fractional differential equations. With the aid of symbolic computation, a variety of exact solutions for them are obtained. Copyright © 2014 John Wiley & Sons, Ltd.     

Thermal Properties and Crystallinity of Thermotropic Liquid Crystalline Copolyesters Prepared from Poly(ethylene terephtalate) (PET) and Rigid Aromatic Units

A series of copolyesters were synthesized by melt‐polycondensation reaction of poly(ethylene terephtalate) (PET) with various proportions of equimolar compositions of p‐acetoxybenzoic acid (p‐ABA), hydroquinone diacetate (HQDA) and terephtalic acid (TPA). Viscosity, liquid crystallinity, thermal properties, degree of crystallinity and thermal stabilitiy of these copolyesters were investigated by Ubbelohde viscometer, hot‐stage polarized light microscopy (PLM), differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and thermogravimetric analysis (TGA), respectively. On the basis of viscosity measurement, it was observed that intrinsic viscosity values of the copolyesters are increased regularly with increasing amounts of aromatic units (p‐ABA, HQDA and TPA) in the polymer chain. Thermotropic liquid crystalline behavior was observed in the copolyesters containing over 50 mol% of rigid p‐ABA/HQDA/TPA aromatic units. DSC analysis of the anisotropic copolyesters revealed broad and weak endotherms associated with the nematic phases, and the melting temperatures were found to be in the processable region. As the mol% of PET in the polymer chain increased, the specific enthalpies of fusion and the degree of crystallinity of the copolyesters were also increased regularly.     

Highly sensitive detection of urinary cadmium to assess personal exposure

A series of Boron-Doped Diamond (BDD) ultramicroelectrode arrays were fabricated and investigated for their performance as electrochemical sensors to detect trace level metals such as cadmium. The steady-state diffusion behavior of these sensors was validated using cyclic voltammetry followed by electrochemical detection of cadmium in water and in human urine to demonstrate high sensitivity (>200 μA ppb⁻¹ cm⁻²) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the U.S. National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25–1 ppb cadmium.