Due to the scientific and technical development in the free electron laser devices and the accompanying industrial and technological progress in various fields of civil and military life, it became necessary to expand the understanding of the mechanism of interaction of electrons (as an effective medium) with the magnetic field that they pass through to form coherent photons.

    In this paper, the Lorentz force effect is simulated and analysed. The results showed that the Lorentz force originates from the magnetic field, making the electron move through it oscillate. This sinusoidal motion of the electron causes it to emit two photons for every electron wavelength. It has been concluded that the electron velocity directly affe

A computerized investigation has been carried out on the design of six electrodes electrostatic lenses used in electron gun application. The Finite-Element Method (FEM) was used in the solution of Laplace equation for determine the axial potential distribution. The electron trajectory under zero magnification condition. The optical properties, spherical and chromatic aberrations, the object and image focal length and object and image position are calculated. A very good futures for the electron gun with these lenses have been computed where are a beam current of 8.7*10-7A can be supplied using cathode tip of radius 10nm.

     The present computational work is focused on investigating some properties of Gabor lens. The Gabor lens under consideration consists of two fields, electrostatic and magnetic. The Glaser field model is assumed to represent each field along the optical axis. Under zero magnification condition the trajectory of charged particles along the axis of Gabor lens has been computed. The results have shown that a lens of short focal length and hence high refractive power can be achieved

Background: Autism is a complex developmental disability that typically appears during the first three years of life. Autism affects the normal development of the brain in the areas of social interaction and communication skills.Objectives: To identify risk factors for Autism among a sample of autistic children in Baghdad city. Type of the study: this is a case – control, study. Methods: This study was conducted during the period of data collection extended from first of November 2010 until the first of April 2011,The total number of children involved was 100children with diagnosis of autism. Handred children who are free from autism were taken as the control sample. Results: there was a significant association between paternal age and

The harmonic oscillator (HO) and Gaussian (GS) wave functions within the binary cluster model (BCM) have been employ to investigate the ground state neutron, proton and matter densities as well as the elastic form factors of two- neutron 6He and 16C halo nuclei. The long tail is a property that is clearly revealed in the density of the neutrons since it is found in halo orbits. The existence of a long tail in the neutron density distributions of 6He and 16C indicating that these nuclei have a neutron halo structure. Moreover, the matter rms radii and the reaction cross section (𝜎𝑅 ) of these nuclei have been calculated using the Glauber model.

In this work a study and calculation of the normal approach between two bodies, spherical and rough flat surface, had been conducted by the aid of image processing technique. Four kinds of metals of different work hardening index had been used as a surface specimens and by capturing images of resolution of 0.006565 mm/pixel a good estimate of the normal approach may be obtained the compression tests had been done in strength of material laboratory in mechanical engineering department, a Monsanto tensometer had been used to conduct the indentation tests.
A light section measuring equipment microscope BK 70x50 was used to calculate the surface parameters of the texture profile like standard deviation of asperity peak heights, centre lin