نشریه صنایع الکترونیک
سال سوم شماره 2 (پیاپی 9، تابستان 1391)

Long vertically aligned ZnO nanowire arrays were synthesized using a microwave-assisted hydrothermal process for dye-sensitized solar cells application. Using this method, we were able to grow ZnO nanowire arrays at an average growth rate and various lengths. effect ZnO nanowires of various lengths on dye absorption in the dye-sensitized solar cells was investigated and its efficiency has been evaluated in different modes. The results show that the an array of zinc oxide nanowires in solar cells with long structure will be added the efficiency of dye absorption. J–V curves of the fabricated ZnO nanowire-based mercurochrome-sensitized solar cells indicated that the short-circuit current density is increased with increasing the length of the nanowire array. FESEM was used in this paper for survey of long vertically aligned Zno nanowire arrays.

In this paper optimization of frequency offset estimation technique based on channel estimation, which is desirable for frequency selective channels and hasfast convergence speed, for using in HF channel is addressed.Because of time variations coherence time in HF channel is short, which leads to a severe degradation in the performance of above technique in this channel. An optimization of said technique is proposed in which after removing coarse frequency offset estimation and knowing residual frequency offset range, incorrect estimations can be removed and others can be averaged to give final correct estimate. Simulation is conducted underchannel parameters with respect to MIL-STD-188-110B. the results show that proposed optimization result in improved performance of frequency offset estimation technique based on channel estimation.

This paper presents a new classification framework for Iranian license plate character recognition. In this framework, a set of robust features are calculated from license plate characters based on directional projections,kirsch edge detector and local means. The characters are then classified using mixture of experts which use the multilayer Perceptrons (MLPs) as expert and gating networks. The proposed recognition algorithm is evaluated on a database of Iranian license plate characters consisting of 14256 binary images, and the recognition rate of 99.42% is achieved. The proposed algorithm yields better performance of the Iranian license plate character recognition in comparison with conventional methods which use a single MLP neural network.

One of the primary challenges in complex-valued neural networks (CVNNs) is to find an appropriate activation function (AF) that should be differentiable and bounded. The AF should properly map the complex domain into real-valued outputs, when the CVNN is used to process real-valued problems. In this paper, we proposed two novel AFs that well satisfied the above conditions. The proposed AFs saturate in four regions and unlike the simple two-layered perceptron, they are able to solve linear non-separable problems. Weight adjustment formulas are developed, and the learning and testing processes are described for both networks. To evaluate the performance of the proposed scheme, two readily available labeled data sets on diabetes and breast cancer are used to detect the respective illnesses. It has been shown that the proposed CVNNs have simpler structures and faster convergence rate than an standard multi-layered real-valued perceptron. The proposed scheme achieves correct diagnosis rates of 80% and 95% for diabetes and breast cancer, respectively in the corresponding data sets.

In this paper, the electromagnetic fields for cylindrical cloak are investigated in detail. The exact wave solution for different regions is derived. For two case of illumination, electric line source inside and outside of cylinder, the scattering fields calculated and validated with full-wave simulations results based on COMSOL Multiphysics. Based on results of this study, the electromagnetic cloak can be used as an electric shield with the least scattering cross section.

This paper suggests a type of cloak making the object invisible in its actual position and creating a deceptive, bigger image of the object showing it in a chosen place of space. Not only does the mentioned cloak move the image of the object radially, but it is also able to rotate the deceptive image by any arbitrary angle. This cloak consists of two layers of shifter and rotator. The shifter creates the deceptive image in a farther distance from the real object and the rotator is able to spin image by any arbitrary angle.