Journal of Kufa - physics

The Differential Cross Sections (DCS\'s), Total Cross Sections (TCS\'s) and Momentum Transfer Cross Sections (MTCS\'s) of electron and positron scattering by radium and radon atoms were calculated in the range of energy (5–500) eV using a total potential consisting of combining the static, exchange and polarization potentials at long distances. In addition, the correlation potential of Perdew–Zunger at short distances for electrons was used, as well as the correlation potential of Jain for positrons. The exchange potential for positrons was neglected. In this study, a good agreement with other experimental values and theoretical values of many investigators was found.

Turbidity was calculated by solar irradiance (Linke's Turbidity) for sixteen Iraqi sites. These sites were distributed among middle, north and south of Iraq. We have updated these results of turbidity by depending on direct solar radiation, diffuse solar radiation, total solar radiation, and solar constant as inputs for mathematical models in computer programs. The latter calculations taking into account the hours of actual sun shine, hours of theoretical sun shine of the sun, the angle of the sun's rays, and the angle of the sun during the months of the year.
The results showed that turbidity in the Iraqi sites which considered in this research depends mainly on the months of the year regardless of the fact that this site is located in the north, middle or south of Iraq. The amount of turbidity is at its greatest value during the winter season, specifically the month of December, where the average turbidity varied for those sites. In latter month the turbidity was ranged from (4.85 to 5.73), while in January it ranged from (4.75 to 5.72), then it began to decrease until the value of turbidity in most sites reached its lowest level in September, where the average turbidity of the studied sites varied (except for the site of Najaf) in this month (2.82 - 3.10) While the Najaf site was unique in registering the lowest average amount of turbidity in June by (3.25). The results showed that the turbidity in all sites included in this research ranges between (2.82 - 5.73) during the year.

The short backfire antenna is one of the important types of antennas due to its high directional and other characteristics. Therefore, this research deals with, a theoretical study to calculate the radiative structures of a short backfire antenna as an axially symmetric body using the moment method.
The main goal is to theoretically calculate the radiation fields and compare them with previous practical researches. Where the mathematical analysis with the used software was verified by comparing the results and noting the extent of the match.
The other goal is to study the effect of the antenna dimensions on its performance by studying the effect of adding a rim to the edge of the large back reflector, as well as studying the change of the radius of the two reflectors (large and small), where it was confirmed that the best value for the radius of the large reflectors and small (Rm=1λ) (Rs= 0.25 λ) respectively.

The short backfire antenna is one of the important types of antennas due to its high directional and other characteristics. Therefore, this research deals with, a theoretical study to calculate the radiative structures of a short backfire antenna as an axially symmetric body using the moment method.
The main goal is to theoretically calculate the radiation fields and compare them with previous practical researches. Where the mathematical analysis with the used software was verified by comparing the results and noting the extent of the match.
The other goal is to study the effect of the antenna dimensions on its performance by studying the effect of adding a rim to the edge of the large back reflector, as well as studying the change of the radius of the two reflectors (large and small), where it was confirmed that the best value for the radius of the large reflectors and small (Rm=1λ) (Rs= 0.25 λ) respectively.

The research included the preparation and then studying the structural and optical properties of the cobalt dioxide (CoO2)films. The latter films were prepared using a semi-computerized spray pyrolysis technique (SCSPT),. The X-ray diffraction gave polycrystalline nature with crystal system trigonal (hexagonal axes), and the Energy Dispersive X-ray spectroscopy (EDX) showed that all films contain the elements (Co and O) indicating formation of (CoO2) films with high purity. FTIR measurements showed of chemical bonds of CoO2 clearly. Scanning Electron Microscopy (SEM ) Showed clearly that the formed thin films under the optimum conditions were homogeneous, dense and compact, and Atomic Force Microscopy(AFM) results showed that the topography of the film surface where surface roughness was found to be 7.91 nm, root mean square was 9.69 nm., and the average granularity diameter was 78.00 nm. The optical properties (absorbance, absorption coefficient, extinction coefficient, refractive index, optical Conductivity, the real and imaginary part of the dielectric constant )were decreased with increasing the wavelength, while the transmittance increases with increasing wavelength. The optical energy gap was (1.98eV) and this is a good optical energy gap values for photovoltaic applications.

Thin films of TiO2nanostructures were prepared on FTO bases with different temperatures 140 ° C and 160 °C for 4 h. The XRD results showed that that there was an increase in the intensity of the peaks of the prepared (quadrangular) samples and a decrease in the FWHM was observed due to the increase in temperature as well as increase in the grain size in which the distance between the grains was decreased. According to the UV-Vis results, the energy band gap Egwas calculated from the reflectivity spectrum using the Kobelka -Monk equation. The increase in temperature has reduced the energy band gap, which shifting it towards the blue direction.FESEM, an increase in the surface thickness of the thin film due to an increase in the preparation temperature. The solar cell efficiency was decreased with increased in temperature. Where it was found the efficiency reduce rom 0.17% to 0.004% for As for 140 ° C and 160 ° C respectively