In this paper, considers a solution of Maxwell's curl equations by using the finite-difference time-domain (FDTD) method. We simulated electromagnetic waves propagation in free space. The electric and magnetic fields generated in two cases to make a comparison between the models. All models were computed using the same parameters. This study showed that the intensities of the fields affected when adding three excited sources pointed in three locations. However, it was noted that three sources placed in the same location improved the distributions of the fields. Therefore, this difference in excitation position leads to change the image intensity distribution. arabic 7 English 43
Adel G Diyaf, Sedig S. Farhat(4-2017)

تمت دراسة تأثير أيون الصوديوم على الخواص الفيروكهربائية للمركب (NaxBa1-xTiO3) بقيم (x=0.0,0.3,0.4,05)، الذي تمّ تحضيره بطريقة (تحضير المواد السيراميكية الالكترونية المنشورة والمألوفة). التأثير لدرجة الحرارة في المدى (RT-160ºC) والتردد في المدى (0.01,0.1,1KHz) على السماحية الكهربائية، وكذلك على الفقد العزلي الكهربائي، في الوسط الفيروكهربائي. نتائج أشعة –X [XRD]. تبين أن العينات النقية والمطعمة تتشكل في التركيب البلوري المتماثل عند درجة حرارة (1100ºC). عند درجات حرارة الأعلى من نقطة كوري، قيم السماحية النسبية تحقق قانون "كوري وايز" في المدى الباراكهربائي. طاقة التنشيط لكل العينات تمّ حسابها من منحنى آرهينيوس. Abstract The effect of sodium doping was studied on ferroelectric properties of (NaxBa1-xTiO3) with x= 0.0, 0.3, 0.4 and 0.5 prepared through solid-state route. The effect of temperatures in the range of (RT-160ºC), frequencies (0.01, 0.1 and 1 KHz), and doping ration on the dielectric permittivity and dielectric loss were studied in ferroelectric region. The X-ray diffraction [XRD] results indicate that pure and doped samples crystallize in to tetragonal symmetry on heat treatment at (1100ºC). Above the Curie temperature, the relative permittivity follows curi-weiss law in the paraelectric region. The activation energies were calculated from the (Arrhenius-plot) for all samples.
عبد الرحمن رجب علي النيفرو (2008)

Integrating photonic microstructures into organic light-emitting diodes (OLEDs) has been a widely used strategy to improve their light out-coupling efficiency. However, there is still a need for optical modelling methods which quantitatively characterise the spatial emission pattern of microstructured OLEDs. In this paper, we demonstrate such rigorous calculation using the reciprocity theorem. The calculation of the emission intensity at each direction in the far field can be simplified into only two simple calculations of an incident plane wave propagating from the far field into a single cell of the periodic structure. The emission from microstructured OLED devices with three different grating periods was calculated as a test of the approach, and the calculated results were in good agreement with experiment. This optical modelling method is a useful calculation tool to investigate and control the spatial emission pattern of microstructured OLEDs. arabic 12 English 89
Adel Diyaf, Emiliano R. Martins, John I.B. Wilson, Graham A. Turnbull, Ifor D.W. Samuel, (7-2015)