Effect of post annealing temperature on structural and optical properties of ZnCdO thin films deposited by sol–gel method

Ternary ZnCdO thin films oriented along c-axis have been successfully deposited on p-Si (1 0 0) substrates using sol–gel spin coating route. To optimize most suitable annealing temperature for the Zn_1−xCd_xO thin films; these films with selected cadmium content x = 0.10 were treated at annealing temperatures from 300 °C up to 800 °C in oxygen ambient after deposition. The structural and optical properties of deposited thin films have been characterized by X-ray diffraction, energy dispersive spectroscopy, atomic force microscopy, UV–Vis spectroscopy, and photoluminescence spectra. The results show that the obtained films possess high crystallinity with wurtzite structure. The crystallite size, lattice parameters, lattice strain and stress in the deposited films are determined from X-ray diffraction analysis. The band gap energy increased as a function of annealing temperatures as observed from optical reflectance spectra of samples. The presence of Cd in the deposited films is confirmed by energy dispersive spectrum and it is observed that Cd re-evaporate from the lattice with annealing. The photoluminescence measurements as performed at room temperature did not exhibit any luminescence related to oxygen vacancies defects for lower annealing temperatures, as normally displayed by ZnO films. The green yellow luminescence associated to these defects was observed at higher annealing temperatures (≥700 °C).     

Study of ion transport and materials properties of K+-ion conducting solid polymer electrolyte (SPE): [(1-x) PEO: xCH3COOK]

Study of ion transport behavior in K⁺-ion conducting solid polymer electrolyte (SPE) films: [(1-x) PEO: xCH₃COOK] has been reported. Poly (ethylene oxide) PEO has been used as polymeric host and potassium acetate: CH₃COOK as complexing salt. SPE films in varying salt concentrations have been prepared by hot-press cast method. SPE film: [95PEO: 5CH₃COOK] has been identified as Optimum Conducting Composition (OCC) with room temperature conductivity (σ _rt) ~ 2.74 × 10⁻⁷ S/cm. As a consequence of salt complexation in polymeric host, σ _rt-enhancement of approximately two orders of magnitude was achieved in SPE OCC film. Ion transport property has been characterized in terms of ionic conductivity (σ), total ionic (t _ion)/cation (t ₊) transference numbers using different ac/dc techniques. Temperature-dependent conductivity measurement was done to explain mechanism of ion transport and to evaluate activation energy (E _a). XRD, FTIR, and DSC techniques were used to study materials property in SPE OCC film which also confirmed the complexation of salt in the polymeric host as well as increase in degree of amorphousity.

     

Relativistic Effect on Guided Wave Propagation through Isotropic Lossy Plasma

The dispersion relations and cut-off frequencies for the appropriate modes existing inside the relativistically moving lossy isotropic plasma waveguide are studied and are found to depend on waveguide dimensions, plasma-parameters and the drift velocity of plasma medium. The field as well as power flow are also studied in detail and it is found that the fields as well as power flow for TE modes are unchanged while for TM modes they are modified depending on the drift velocity of the plasma medium. The results are compared with those obtained for the case of lossless relativistically moving and lossy stationary plasma waveguides.     

Single cell discretization of O(kh2 + h4) for the estimates of ${\partial u}\over{\partial n}$ for the two‐space dimensional quasi‐linear parabolic equation

In this article, new stable two‐level explicit difference methods of O(kh² + h⁴) for the estimates of for the two‐space dimensional quasi‐linear parabolic equation are derived, where k > 0 and h > 0 are grid sizes in time and space directions, respectively. We use a single computational cell for the methods, which are applicable to the problems both in cartesian and polar coordinates. The proposed methods have the simplicity in nature and employ the same marching type technique of solution. Numerical results obtained by the proposed methods for several different problems were compared with the exact solutions. © 2001 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 17: 250–261, 2001     

Behavior prediction of washing system in a paper industry using GA and fuzzy lambda–tau technique

Availability analysis has been an important issue in the design field of any Industrial system as the system structure has become more complicated. Also, the system availability is affected by many factors such as design, manufacturing, installation, etc., and so it may be extremely difficult to model, analyze and predict the failure behavior of the system. The purpose of this paper is to develop a new approach for computing various performance measures, namely reliability, availability, MTBF (mean time between failures), ENOF (expected number of failures), failure rate and repair time, for any industrial system. In the proposed approach, the failure rates and repair times of all constituent components are obtained using genetic algorithms and then various performance measures are computed using fuzzy lambda–tau methodology. Washing system, the major part of paper industry is the subject of study. The interactions among the working components are modeled using Petri nets. Failure and repair rates are represented using triangular fuzzy numbers as they allow expert opinion, linguistic variables, operating conditions, uncertainty and imprecision in reliability information to be incorporated into system model. Based on calculated reliability parameters, a structured framework has been developed that may help the maintenance engineers to analyze and predict the system behavior.     

A laminate-based framework for switching and microstructure evolution in polycrystalline ferroelectrics

This contribution deals with the numerical modelling of polycrystalline ferroelectric materials considering a sequential laminate-based approach established for tetragonal single-crystal ferroelectrics. The particular model [1] is considered and extended to predict the material behaviour of poly-crystal tetragonal ferroelectric ceramics. The derived laminate-based model is implemented in a finite element environment to simulate the time-dependent domain evolution and switching response of a bulk polycrystalline ferroelectric ceramic. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Differentiation of Operator Functions and Perturbation Bounds

Given a smooth real function f on the positive half line consider the induced map on the set of positive Hilbert space operators. Let f ^(k<) /E5> be the k ^th derivative of the real function f and >E5>D ^k f the k ^th Fréchet derivative of the operator map f. We identify large classes of functions for which , for k= 1,2,... . This reduction of a noncommutative problem to a commutative one makes it easy to obtain perturbation bounds for several operator maps. Our techniques serve to illustrate the use of a formalism for “quantum analysis” that is like the one recently developed by M. Suzuki. Received: 4 April 1997 / Accepted: 28 May 1997     

Study of some metallic silicates as ion-exchangers

The extraction of ammine complexes of Cu²⁺, Cd²⁺, Ni²⁺, Co²⁺ and Zn²⁺ by synthesised manganese, nickel and zinc silicates has been studied at different pH and ionic concentrations in the external solution. It has been found that the uptake of the metal ion Co²⁺, Cu²⁺ and Zn²⁺ increases with increase in pH of the external solution, attains a maximum and then decreases. However, the uptake for Cd²⁺ and Ni²⁺ increases continuously. The q_A values of all the silicates increases with the increase in the concentration of the exchanging ion and its order for the investigated metal ions is Ni²⁺ < Co²⁺ < Cd²⁺ < Zn²⁺ < Cu²⁺.     

Asymmetric Diels-Alder reactions with a chiral spirodione, (6S, 7S, 10R)-7-Isopropyl-10-methyl-1-oxaspiro[5.5]undec-3-ene-2,5-dione

The synthesis of the title spirodione, a new class of auxiliary based chiral synthon, using (−)-menthone having a unique carbon-carbon bond is described. Diels-Alder reactions were carried out with variety of dienes using the title auxiliary as a chiral dienophile in the presence of diethyl aluminium chloride as Lewis acid catalyst to afford the cycloadduct with good diastereoselectivity. The configurations of the chiral synthon and cycloadducts were determined by X-ray crystallography. Methodology for detachment of the chiral auxiliary from the cycloadducts has been developed.     

Nickel-catalyzed highly regio- and stereoselective three-component assembly of allenes, aryl iodides, and alkenylzirconium reagents

Cyclohexylallene (1a) and alkenylzirconium reagent (n-PrCH=CHZr(Cp)2Cl) undergo three-component assembly with a variety of aromatic iodides (R1-I: R1 = 4-PhOMe, 4-PhCOMe, 4-PhMe, 2-thiophene, 2-PhOMe, 3-PhOMe, and 4-PhCO2Et) in the presence of NiCl2(PPh3)2 and zinc powder in THF at 50 degrees C to afford corresponding three-component assembly products in moderate to good yields with very high regio- and stereoselectivity. In addition to cyclohexylallene, also phenylallene, n-butylallene, cyclopentylallene, and cycloheptylallene underwent the three-component assembling reaction to furnish the corresponding 1,4-diene derivatives in good yields. Several alkenylzirconium reagents (R2CH=CHZr(Cp)2Cl: R2 = Ph (3b), t-Bu, TMS) were also employed for this three-component assembly. The nickel-catalyzed three-component assembly was further extended to vinyl iodides. Thus, 1a reacts with 3b and ethyl (Z)-3-iodoacrylate to produce a highly substituted triene in excellent yield. In all of these three-component assembly reactions, the E isomers were formed predominantly with E/Z ratios between 94/6 and 99/1. A possible mechanism for this highly regio- and stereoselective three-component assembly is proposed.