The Effect of Zn Concentration on the Optical Properties of Cd_10–xZn_xS Films for Solar Cells Applications

In this paper, Cd10–xZnxS (x = 0.1, 0.3, 0.5) films were deposited by using chemical spray pyrolysis technique, the molar concentration precursor solution was 0.15 M/L. Depositions were done at 350?C on cleaned glass substrates. X-ray diffraction technique (XRD) studies for all the prepared film;all the films are crystalline with hexagonal structure .The optical properties of the prepared films were studied using measurements from VIS-UV-IR spectrophotometer at wave-length with the range 300 - 900 nm;the average transmission of the minimum doping ratio (Zn at 0.1%) was about 55% in the VIS region, it was decrease at the increasing of Zn concentration in the CdS films, The band gap of the doped CdS films was varied as 3.7, 3.8, 3.6 eV at x = 0.1, 0.3 and 0.5 respectively.

Determination of threshold random gain medium in dye: Polymer films containing TiO₂nanoparticles

Random gain medium based on organic Rhodamine 590 (R590) laser-dye and Titanium dioxide (TiO2) suspended nanoparticles have been prepared with polymethylmethacrylate (PMMA) as a host. Spray-coated homogeneous film samples of 22.4 μm thickness. Optimum concentrations have been determined depending on the normal fluorescence spectra which give evidence that the laser dye provides amplification and TiO2 nanoparticles act as scatter center. At the optimum concentrations, results of the random gain medium under second harmonic Nd: YAG laser excitation shows that the values of bandwidth at full width half-maximum (FWHM) and the threshold energy are about 11 nm and 10 mJ respectively.

Study the Radial Expansion of SN 1987A Using Counting Pixels Method

Physical properties of supernova 1987A were investigated including: Expansion velocity;Current mass;Radius;Temperature and the Rate of the expansion by applying Counting Pixels Method (CPM) in comparison with the application of the Povida and Self-Similar Solution theoretical models which in forced the idea for adopting such a model to be applied for supernova type II. Then tow results are found to be in a good agreement with the Self-Similar solution model rather than that of Povida model. The high density of the region that surrounded the exploding system acting as decelerating parameter and down the expansion velocity of the supernova from 3900 km·s-1 to 1200 km·s-1 during the past 23 years from the explosion, with a current size equal 0.39 pc, and with an expansion rate of 0.41 per a year.

Random Laser of R6G Dye and TiO₂Nanoparticals Doped in PMMA Polymer

The random laser (RL) based on organic Rhodamine 6G (R6G) laser- dye and Titanium dioxide (TiO2) suspended nanoparticles have been prepared with polymethylmethacrylate (PMMA) as a host. Both liquid and spray-coated homogeneous film samples of 22.4 μm - 30.1 μm thickness range were use. Optimum concentrations have been determined depending on the normal fluorescence spectra which give evidence that the laser dye provides amplification and TiO2 nanoparticles as scatter center. At the optimum concentrations, results of the random laser (RL) under second harmonic Nd: YAG laser ex-citation show that the values of bandwidth at full width half-maximum (FWHM) and the threshold energy are about 9 nm and 15 mJ respectively, which represent the minimum value for the liquid samples in the current research. Correspondly, these values become 14 nm and 15 mJ for film sample. The broadening that can be attributed to the concentration quenching of a laser dye at high concentration levels has been observed.

Determination of Velocity and Radius of Supernova Remnant after 1000 yrs of Explosion

Supernova explosions are described as very violent events which transfer a significant amount of energy to interstellar media and are responsible for a large variety of physical processes. This study does not discuss the actual explosion mechanisms but follows the behavior of the dynamical evolution of some selected type I and type II supernova remnant and particularly after a thousand years from their explosion and shows how the density of the medium affects the evolution and the lifetime of each remnant. By studying such behaviors, a simplified model has been proposed here for the velocity and radius of the remnant after thousand years of explosion that depends only on the density of the medium and age of the remnant. It has been found that all types of supernova remnants have similar behaviors after a thousand years from their explosion despite their origin formation. Moreover, it is demonstrated that, when those selected remnants have entered or will enter into their radiative phase, an idea on their physical properties will be obtained.