Current Issue Date 01-11-2018 to 31-01-2019
Abdelhmid M. Younis and Salha D. Y. Alsaadi
The purpose of this work was to study the transfer factor (TF) from soil to grass in Al- Bayda area in North East of Libya to be added to the data base for this part of the world, and to be informed about health safety of the radiation hazard due consumption of animal products. Five sites were measured for their radioactivity concentration for the followings: the activity concentrations of samples in soil and grass (Bq/kg) of 238U, 232Th, 40K and 137Cs. We found that the average radioactivity concentration of 40K > 238U> 232Th> 137Cs in soil and mixed grass samples. Our results show higher values for TF according to IAEA 6 report.
The exact solutions of the Woods-Saxon potential with centrifuge term in arbitrary dimensions D were obtained within the proper quantization rule. Dealing with the centrifuge term in Woods-Saxon potential by the Pekeris approximation. The inter-dimensional degeneracies for various orbital quantum number l and dimensional space D were studied.
In this paper, we present a novel technique for digital watermarking images based on geometric moment invariants. In image watermarking, geometric transformation is the most challenging problem in all kinds of attacks. Embedding the watermark into the normalized image is an idea of this kind of algorithms. However, because the sizes of the normalized original image and the normalized geometrically attacked image are different known, and also the synchronization of the embedding and the extracting are very different to be achieved. In order to solve this problem, we propose an image watermarking based on geometric moment invariants. Watermark is composed of the mean values of eleven geometric invariant moments to translation, scaling and rotation. Watermark detection is as simple as computing the moment invariants of the received image. The experiment results demonstrate the proposed method can obtain better visual effect, meanwhile, it is also robust enough to some image degradation processing
Based on the interference theory of light, the influence of the light source's non-monochromaticity on the visibility of Michelson's equal inclination interference fringe is analyzed. The Matlab is used to simulate the numerical simulation and experimental simulation of the equal inclination interference fringe visibility. The visualized visual image is used to visualize the abstract temporal coherence theory. At the same time, it has certain guiding significance for the theoretical teaching and practical application of Michelson interferometer.
Han Li Jun and Yi Feng
MIMO technology makes use of the wireless channel in the increased space to transmit and receive signals simultaneously with multiple antennas at the transmitter and receiver. Since the signals transmitted simultaneously by each transmitting antenna occupy the same frequency band, it can multiply the system capacity and spectrum utilization without increasing the bandwidth1. In this paper, the block diagram of MIMO system is given, and the capacity of MIMO system is analyzed theoretically. Finally, the performance of MIMO system is simulated by simulation software, which verifies the correctness of the theory.
With the expansion of the application of brushless DC motor, its performance requirements are getting higher, and the control system is to improve the control of brushless DC motor an important means. Firstly, the mathematic model is established for the brushless DC motor. Secondly, the closed loop control strategy of speed current and its implementation are analyzed in detail. The simulation model of brushless DC motor control system is set up in Matlab / Simulink environment, and the simulation under different working conditions, such as step - down regulation and variable torque control. The simulation results show that the brushless DC control system has the advantages of wide adjustment range, fast response and high accuracy. It provides support for brushless DC motor and its control system in practical application
Bi-ying Zhou, Peng Zhang
In controlled field studies, the control problem of nonlinear systems has been a research focus. Unable to get accurate mathematical models for complex nonlinear systems, neural networks because of the characteristics of a powerful approximation ability to solve complex nonlinear system control problems provides new ideas and methods. Aiming at the problem of identification of nonlinear systems is difficult to compare the BP neural network and RBF neural network prediction results in delay nonlinear system model prediction. Simulation results show that RBF neural network can achieve greater recognition accuracy results.
Peeyush Ranjan and L. K. Mishra
Using the theoretical formalism of US Pracht etal [arXiv:1302.6155v2 [cond-mat.supr-con] 3.may 2013, [Phys. Rev B 86, 184503 (2012) and A Semenov et. al [The European Phys. Journal B47, 495 (2005)], we have theoretically studied electrodynamics and evaluated superconducting and optical properties of ultra thin film at THz frequencies. Our theoretically evaluated results of real and imaginary part of complex optical conductivity σ1 and σ2 as a function of 2Δ(T)ħω for different temperature and fixed film thickness show that both σ1 and σ2 decrease with the function 2Δ(T)ħω for all the temperature taken. Our theoretically evaluated results of superconducting transition temperature TC (K) increase with film thickness d .Our theoretically obtained results of real and imaginary part of dielectric constant ε1 and ε2 as a function of wavelength and fixed film thickness indicate that ε1 decrease with wavelength and crosses positive and negative value as wavelength increases. However the value of ε2 increase with wavelength for all film thickness d and its values are always positive.Our evaluated results of absorbance as a function of wavelength for different film thickness decrease with wavelength Our evaluated results of real and imaginary part of the impedance for a film thickness 5.6nm indicate that real part of the impedance Ω increase while imaginary part decrease with wavelength. Our evaluated results of temperature dependent upper critical field BC2 (T) for different film thickness decrease Our evaluated results of Density of states at the Fermi level N0 as a function of film thickness increase with thickness d. Our evaluated results of energy gap parameter 2Δ(T) mev as a function of temperature for NbN and TaN film decrease with T and becomes zero at T=TC. The results are in accordance with the BCS theory. Our evaluated results of the ratio 2Δ(0) /K β Tc as a function of TC in the vicinity of TC show anomalous behavior. The ratio is 4.507 for NbN thin film (TC=12.5K) and 4.082 for TaN thin film (TC=9.7K) respectively. In this paper, we have evaluated superconducting and optical properties at THz frequencies. These films were grown on Sapphire and evaluated by means of spectral ellipsometry and dc measurement of superconducting critical temperature. The films are well described by the scattering matrix method and with BCS and Drude theory. Our evaluated results are in good agreement with other theoretical workers. These results are quite useful and fruitful in analyzing various devices for nano-photonics.
Farah T. M. Noori, Aws K. Mohammed, Sabah A. Salman, Hayder Saleem Hussain
Polymer-ceramic bio-nanocomposites, consisting of Barium Strontium Titanate BaxSr1-xTiO3 (x= 0.6, 0.7) (BST) as fillers and Poly (vinylidenefluoride) (PVDF) as matrix, have been fabricated by using a spin coating method with (BST) filler contents of (25,40) vol%. (BST) nanopowder was synthesized by hydrothermal method. The optical properties of (PVDF/BST) nanocomposites were studied from the absorbance spectrum, the absorbance of the BaxSr1-xTiO3 (x= 0.6, 0.7) nanocomposites increase after gamma irradiation with doses (4.32 kGy) and (4.98 kGy). The optical energy gap for the allowed direct electronic transition of (PVDF/BST) nanocomposite with different filler contents of (BST) decrease after gamma irradiation with doses (4.32 kGy) and (4.98 kGy).
Sameera Attanayake, Masayuki Okuya and Kenji Murakami
We investigated the spray angle dependence for the growth of aluminum doped zinc oxide 1-D nanostructure by using the advanced spray pyrolysis deposition (SPD) technique of rotational, pulsed and atomized. We have successfully synthesized Al-doped ZnO 1-D nanostructure on the fluorine doped tin oxide (FTO) glass substrate and characterized optical, morphological and electrical properties. Hexagonal wurtzite structure oriented along c-axis were confirmed by x-ray diffractogram and atomic force microscopy images. The surface morphology was observed by field emission scanning electron microscopy. Nanorod array with the excellent structural properties was obtained when lowering the spray angle. The average diameter of 29.92 nm and nanorod density of 86.20 nanorods per µm2 was found at lower spraying angle, while the optical transmittance in the visible range was 80.3% and electrical conductivity was 9.4 ×103 Ω-1 cm-1.
Duaa N. Jasim, Sabah A. Salman, Asaad A. Kamil
The pure film of polymer (PVA) and films filled with Manganese Chloride (MnCl2.4H2O) salt with different weight ratios ((3, 7, 11,15 ) wt%) have been prepared by using casting method. The mechanical properties of (PVA-Manganese Chloride) composites films have been studied. The results of the mechanical tests show that the fracture energy of the composites films is increased with increasing the weight ratio of the added Manganese Chloride salt, and the results show that the hardness for composites films increased and decreases with increases the weight ratio of the added Manganese Chloride salt, while the results of the tensile tests show unsystematic values for tensile strength and Young's modulus for composites films after filling with different weight ratios of the added Manganese Chloride salt. While shows unsystematic increasing for the elongation at break after filling with different weight ratios of the added Manganese Chloride salt.