Electrical Characteristics of Al/Poly(methyl methacrylate)/p-Si Schottky Device

Al/Poly(methyl methacrylate)(PMMA)/p-Si organic Schottky devices were fabricated on a p-Si semiconductor wafer by spin coating of PMMA solution. The capacitance–voltage (C–V) and conductance–voltage (G–V) characteristics of Al/PMMA/p-Si structures have been investigated in the frequency range of 1 kHz–10 MHz at room temperature. The diode parameters such as ideality factor, series resistance and barrier height were calculated from the forward bias current–voltage (I–V) characteristics. In order to explain the electrical characteristics of metal–polymer–semiconductor (MPS) with a PMMA interface, the investigation of interface states density and series resistance from C–V and G–V characteristics in the MPS structures with thin interfacial insulator layer have been reported. The measurements of capacitance (C) and conductance (G) were found to be strongly dependent on bias voltage and frequency for Al/PMMA/p-Si structures. The values of interface state density (D _it) were calculated. These values of D _it and series resistance (R _s) were responsible for the non-ideal behavior of I–V and C–V characteristics.     

Refractive index and extinction coefficient determination of an absorbing thin film by using the continuous wavelet transform method

We present the continuous wavelet transform (CWT) method for determining the dispersion curves of the refractive index and extinction coefficient of absorbing thin films by using the transmittance spectrum in the visible and near infrared regions at room temperature. The CWT method is performed on the transmittance spectrum of an a - Si(1-x)C(x):H film, and the refractive index and extinction coefficient of the film are continuously determined and compared with the results of the envelope and fringe counting methods. Also the noise filter property of the method is depicted on a theoretically generated noisy signal. Finally, the error analyses of the CWT, envelope, and fringe counting methods are performed.     

Modeling and optimization of fine coal beneficiation by hydrocyclone and multi-gravity separation to produce fine lignite clean coal

We evaluated the suitability, contribution to the national economy, and environmental impact of hydrocyclone and Multi-Gravity Separation (MGS) processes using fine-sized coal taken from the Soma coal sludge pond. The lignite coal tailings were treated by a two-stage concentration scheme for the recovery of fine clean coal. Pre-enrichment experiment parameters were determined by the Taguchi experimental design method, and the results were interpreted by the Statistical Packages for the Social Sciences (SPSS) 15.0 program to evaluate the optimum parameter values. The tailings initially contained 54.82% ash and had a LCV of 2,279 kcal/kg; after hydrocyclone pre-enrichment, the concentrate was 42.60% ash and had a calorific value of 2,573 kcal/kg (55.75% coal yield). After the final enrichment process, the ash of the pre-concentrated coal was decreased to 24.21% and left a clean coal with a base calorific value of 3,226 kcal/kg (36.16% coal yield). The total sulfur of the obtained clean coal was 0.52% and the combustible sulfur rate was 0.10%. To reduce the ash content of the obtained clean coal, a decantation process was performed that decreased the ash content to 21.84% and the base calorific value was increased to 4,109 kcal/kg.     

A study of the effect of random dopant-concentration fluctuations on current in semiconductor superlattices

The influence exerted by random dopant-concentration fluctuations on the current–voltage characteristics of the current flowing through a semiconductor superlattice has been studied. It was shown that the characteristics of the current flowing through the superlattice noticeably vary with the amplitude of fluctuations of nanostructure parameters. It was possible to find for a small sample the probability-density distribution of the integrated absolute values of the difference of currents at various amplitudes of the dopantconcentration fluctuations.     

Role models—implementation‐based approaches to using roles

A role of an entity can be defined as the set of properties that are important for an object in order to behave in a certain way, as expected by a set of other objects. A role model is a software that specifies a style of designing and implementing roles. This paper evaluates roles in the context of modeling dynamic systems by examining its foundations, surveying the recent role models available for academic use and giving implementation examples. Copyright © 2010 John Wiley & Sons, Ltd.     

Discovering mappings in hierarchical data from multiple sources using the inherent structure

Unprecedented amounts of media data are publicly accessible. However, it is increasingly difficult to integrate relevant media from multiple and diverse sources for effective applications. The functioning of a multimodal integration system requires metadata, such as ontologies, that describe media resources and media components. Such metadata are generally application-dependent and this can cause difficulties when media needs to be shared across application domains. There is a need for a mechanism that can relate the common and uncommon terms and media components. In this paper, we develop an algorithm to mine and automatically discover mappings in hierarchical media data, metadata, and ontologies, using the structural information inherent in these types of data. We evaluate the performance of this algorithm for various parameters using both synthetic and real-world data collections and show that the structure-based mining of relationships provides high degrees of precision.     

Analytical synthesis of robust controllers of the given accuracy under external perturbations

An approach that allows finding a set of robust statistic feedback controllers that ensure the given control accuracy for the controlled parameters in a multiconnected control system under bounded parametric and external perturbations of various classes is proposed. To describe the set of controllers of the given accuracy, the results of analytically solving the matrix equations based on matrix canonization and parametrization of the Lyapunov equation are used. The solvability conditions of the synthesis problem ensure the robustness and optimal suppression of the perturbations. They are homogeneously represented as linear matrix inequalities obtained based on the Lyapunov functions. A methodological example is given.     

Joint quantity flexibility for multiple products in a decentralized supply chain

In this study, we analyze a decentralized supply chain with a single retailer and a single manufacturer where the retailer sells multiple products in a single period. The products differ in terms of a limited number of features only. The retailer places initial orders based on preliminary demand forecasts at the beginning of the period and has an opportunity to modify its initial order after receiving perfect demand information. However, the final orders of the retailer are constrained by its initial orders. The manufacturer has two options for procurement. The first procurement option is regular delivery at the beginning of the period, after the initial orders of the retailer. The next one is expedited delivery, after the updated orders are received. In this setting, our objective is to characterize the optimal policies for the retailer and the manufacturer, and assess the benefits of flexibility.     

Crystal Structures and Magnetic Properties of the Co2Mn1−x V x Sb (0 ≤ x ≤ 1) Heusler Compounds

Crystal structure and magnetic properties of the Co₂Mn_1?x V _x Sb (0 ≤ x ≤ 1) Heusler compounds have been studied by X-ray powder diffraction (XRD), magnetometric measurements, and full-potential linearized augmented plane wave (FP–LAPW) method. All compounds crystallize in a cubic Cu₂MnAl-type crystal structure with the space group Fm–3m. The samples for x<0.8 have the Curie temperatures above room temperature, while the Curie temperature is observed at 68 K for the sample with x = 0.8. The saturation magnetization at 5 K decreases linearly with increasing vanadium concentration x. The values of the saturation magnetization obtained by FP–LAPW–local density approximation (LDA) calculations are in better agreement with the experimental results compared with the results obtained by FP–LAPW–generalized gradient approximation (GGA) calculations.     

Analysis of porous alkaline Cd-electrodes. III. The application of charge porosity diagrams in electrode design

A simple charge-porosity diagram is presented for the rapid estimation of charge capacity in battery electrodes. Porosity changes reflect differences in mole volumes of the reactants and reaction products. Each system has a specific sensitivity to porosity changes. This diagram can be a useful tool for the assessment of mass and current transport performance of electrodes that give insoluble reaction products. Alkaline Cd, Zn and Fe electrolytes are compared.