A computer theoretical s1udy has been carried out in field of opto - clcctroniccs, to design  an electron  gun using the space charge effect.

The   distribution  of   axial  potential    upon   the  two   -electrode

immersion  lens  of  (L=l4mm)  has been  carried   out   using   Poisons equation and the  tinite  clement  method;  knowing  the first 11nd second derivation  of  the    axial   potential   and  the  solution   of  paraxial   ray equation, the  optical   prop

Since her early beginning in 1974 in her novel "Les armoires vides", Annie Ernaux writing about life in all its various aspects remained her main goal. This novel gave the earliest signals of what would happen later on in her literary career. Indeed, her works showed abilities of echoing reality, her sufferance and experiences via the use of simple and clear language. Add to this, her writings are to be viewed as an expression of deep felt journey, and a continuous search due to the consequent changes coming out of her identity.

    We try here to give an answer to the question about writing as to whether being, to Ernaux herself, a need for the search about her social and feminist identity, or a pure literary work

Andalucía, dentro del mapa lingüístico español, es una región con muchas variaciones dialécticas. En muchos casos contiene una gran variedad de términos propios de la zona, ya que en esta misma zona se pueden observar muchas subdivisiones dialectales.

En este trabajo, hemos seguido dos tipos de fuentes:

- Directa: Se trata de conseguir la información por medio de cuestionarios distribuidos a informantes de edades y localidades diferentes.

 - Indirecta: Consultando libros para conseguir información y datos básicos del tema, e información sobre las voces y nombres dialectales en la geografía estudiada.

Los lingüistas no árabes suelen quedar perplejos a la hora de  interpretar el  fenómeno de Al-ḍdad, −normalmente traducido en español como palabras  autoantónimas (1)− en la lengua árabe, en el que los arabistas, y entre ellos los españoles, han quedado sombrosos ante este fenómeno. El jefe del tribunal de la defensa de mi tesis me pidió que le explicara este fenómeno según mi teoría “El esquema básico de la referencia”; pues me dijo que no podía  imaginar que una palabra tuviera dos significados opuestos, y en ese momento le expliqué la palabra albayn  البين que significa la separación,  o la relación o  el enlace que comentar

In the current study, we investigate the effect of  (La) substitution  instead of (Cu) on the properties of the superconductor compound  (Bi2Sr2Ca2Cu3-xLaxO10+δ)  with (x=0,0.05,0.1,0.15,0.2). The samples were  prepared  by solid state reaction method(SSR). Xray diffraction technique (XRD) was used to estimate the structural  properties of the specimens which show an orthorhombic crystalline structure for all the specimens.       The results show that the change in ( La) concentration  leads to decrease the concentration of (Bi-2223), increment in (Bi-2212 ) and(Bi-2201) with appearance of some impurities. Also decrease the critical temperature(Tc) with the increase

Abstract

Digital repositories are considered one of the integrated collaborative educational environments that help every researcher interested in developing the education and educational process. The learning resources provided by the repositories are suitable for every researcher, so digital information can be stored and exchanged by ensuring the participation and cooperation of researchers, teachers, and those who are interested, as well as curricula experts, teachers, and students, to exchange each other’s experiences in constantly updating that information as a reason for developing their performance in education. This reveals the importance of the role of educational digital institutions by providing and

The purpose of the current research is to identify the most important problems that primary school students suffer from inside and outside the classroom from the point of view of their teachers. A sample of (100) male and female teachers was chosen from the Rusafa\ second Directorate for the academic year (2018-2019). The research tool was prepared after reviewing literature related to the issue of problems and difficulties facing students or students in the school stage and even at university. The researcher reached several results that were discussed in the fourth chapter, with a set of conclusions based on the results of the research, and come up with several recommendations and suggestions.

In this paper, we introduce an exponential of an operator defined on a Hilbert space H, and we study its properties and find some of properties of T inherited to exponential operator, so we study the spectrum of exponential operator e^T according to the operator T.

A computational investigation is carried out in the field of charged –particle optics with the aid of numerical analysis method using the personal computer. The work is concerned with the design of electron gun with space-charge effect. The Finite element method (FEM) used in the solution of Poison's equation for determine the axial potential distribution of the two-electrode immersion lens operated under zero magnification condition , and from the solution of the paraxial ray equation the optical properties such as the focal length , spherical and chromatic aberration coefficients are determined, also a calculation of the brightness and perveance for the lens. The electrodes geometry was determined in two and three dimensi