Parasitic compensation in CCI-based circuits for reduced power consumption

In this paper, the compensation advantage of the first-generation current conveyor (CCI) over the second-generation current conveyor (CCII) in tunable circuits is shown. For this purpose, a new floating frequency dependent negative resistor (FDNR) simulator using three CCIs is presented and employed in a third-order high-pass filter. The compensation feature of the CCI is shown for the proposed high-pass filter. As a second example, the presented compensation method is tested in a second-order band-pass filter constructed with two CCIs. Applying the proposed compensation technique, the CCI-based circuits can operate in lower biasing currents, which result in lower power consumption.     

Ge-Si-O phase separation and Ge nanocrystal growth in Ge:SiO(x)/SiO(2) multilayers--a new dc magnetron approach

Ge:SiO(x)/SiO(2) multilayers are fabricated using a new reactive dc magnetron sputtering approach. The influence of the multilayer stoichiometry on the ternary Ge-Si-O phase separation and the subsequent size-controlled Ge nanocrystal formation is explored by means of x-ray absorption spectroscopy, x-ray diffraction, electron microscopy and Raman spectroscopy. The ternary system Ge-Si-O reveals complete Ge-O phase separation at 400?°C which does not differ significantly to the binary Ge-O system. Ge nanocrystals of < 5?nm size are generated after subsequent annealing below 700?°C. It is shown that Ge oxides contained in the as-deposited multilayers are reduced by a surrounding unsaturated silica matrix. A stoichiometric regime was found where almost no GeO(2) is present after annealing. Thus, the Ge nanocrystals become completely embedded in a stoichiometric silica matrix favouring the use for photovoltaic applications.     

A comparative study on structural,morphological and photocatalytic properties of anodically grown ZnO nanowires under varying parameters

Journal of Materials Science: Materials in Electronics - In this study, zinc oxide (ZnO) nanowires (NWs) were successfully produced on Zn plates through electrochemical anodization in potassium...     

Multiple attribute decision-making solution to material selection problem based on modified fuzzy axiomatic design-model selection interface algorithm

Material selection, one of the mostly encountered decision problems in material science literature, is still an onerous task for manufacturing organisations. Achieving accurate solution to this issue, the paper developed a model selection interface to enable analytical solutions to different problem concepts in material selection under multiple attribute decision-making (MADM) environments. Specifically, the generic framework of the fuzzy axiomatic design-model selection interface (FAD-MSI) is modified and successfully applied to the different material selection problem concepts. Consequently, the derived problem-model sets can be referred to accomplish further proposals on this era.     

The role of growth parameters on structural,morphology and optical properties of sprayed ZnS thin films

ZnS thin films were prepared by spray pyrolysis technique using aqueous of zinc chloride and thiourea at molar ratio of 1:1, 1:2, and 2:1. The depositions were carried out on substrates heated from 400 to 520 °C The films were then annealed under sulphur atmosphere for 90 min at 450 and 550 °C. The crystallites exhibit preferential orientation along the [002]_α or [111]_β directions. The films were characterized by XRD and SEM. The structure and morphology of sprayed films are controlled by both, the substrate temperature and the precursors molar ratio in the solution. The values of optical bandgap have been determined from the absorption spectra.     

Optimal tuning of PI speed controller coefficients for electric drives using neural network and genetic algorithms

This paper presents a method of tuning Proportional Integral (PI) controller coefficients in the off-line control of a nonlinear system. In this method, the first step is the identification of the system via Artificial Neural Networks (ANNs), using maximum overshoot and settling time obtained from the application circuit for different K_p-K_i pairs. With this in mind, multi-layer ANN, which uses back-propagation of the error algorithm, was used as the learning algorithm. In the second step, the purpose is to find the optimum controller coefficients using the ANN model as the objective function via Genetic Algorithms (GAs). A Digital Signal Processor (DSP-TMS320C50) was used to carry out control applications. The C++ language was used for ANN and GA, and and the Assembly language was used for the DSP. It is determined that maximum overshoot and settling time are very small if the system is controlled by control parameters obtained from the optimization process that uses GA.     

Optimum design of slurry pipelines by genetic algorithm

Various applications of slurry transportation through pipelines exist. A transportation problem is formulated to determine the pipe diameters and amounts of transported slurry from the production to the consumption points. The minimisation of the cost consisting of the pipe and energy cost terms is considered as the objective function. Pipe cost is given as the function of pipe diameters and the energy cost is defined as the function of pipe diameters and slurry amounts. Energy cost is obtained by using the relation that is previously determined after the experimental studies have been made for the magnetite ore. Genetic algorithm is used as the optimisation method and to apply this method a commercially available software written in the C language is used and modified. The proposed methodology to solve this non-linear programming problem is applied to a transportation system and it is found that the proposed methodology has made the complex, labour-intensive solution process very convenient for the users.     

Voltage-mode multifunction filter with mutually independent Q and \omega _0 control feature using VDDDAs

The paper focuses on the application possibilities of the newly presented voltage differencing active building block called voltage differencing differential difference amplifier. Using this active element, a multifunction frequency filter is designed featuring the possibility of mutually independent control of quality factor Q and characteristic frequency \(\omega _0\) by means of active elements. The structure of the filter is based on the idea of the Akerberg-Mossberg (AM) filter, i.e. the integrators in the structure are always realized only by two active elements. This fact results in better phase compensation for the filter. Compared to the AM opamp based filter, the newly proposed structure features high-impedance inputs, low-impedance output, and all basic frequency responses. The performance of the proposed structure has been verified by SPICE simulations using the TSMC \(0.18\,\upmu \hbox {m}\) level-7 SCN018 CMOS process parameters with \(\pm 0.9\,\hbox {V}\) supply voltage.