Density Functional Theory at the generalized-gradient approximation level coupled with large unit cell method is used to simulate the electronic structure of (II-VI) zinc-blende cadmium sulfide nanocrystals that have dimensions 2-2.5 nm. The calculated properties include lattice constant, conduction and valence bands width, energy of the highest occupied orbital, energy of the lowest unoccupied orbital, energy gap, density of states etc. Results show that lattice constant and energy gap converge to definite values. However, highest occupied orbital, lowest unoccupied orbital fluctuates indefinitely depending on the shape of the nanocrystal.
In this paper, CdS/Si hetrojunction solar cell has been made by
Chemical Bath Deposition (CBD) of CdS thin film on to
monocrystalline silicon substrate. XRD measurements approved that
CdS film is changing the structure of CdS films from mixed
hexagonal and cubic phase to the hexagonal phase with [101]
predominant orientation. I-V characterization of the hetrojunction
shows good rectification, with high spectral responsivity of 0.41
A/W, quantum efficiency 90%,and specific detectivity 2.9*1014
cmHz1/2W -1 .
Spin coating technique used to prepare ZnPc, CdS and ZnPc/CdS blend thin films, these films annealed at 423K for 1h, 2h and 3h. Optical behavior of these films were examined using UV-Vis. and PL. The absorption spectrum of ZnPc shows a decreasing in absorption with the increase of annealing time while CdS spectrum give a clearly absorption peak at~510 nm. Energy gap of ZnPc increases from 1.41 to 1.52 eV by increasing the annealing time. Eg of CdS decrease by increasing annealing time, from 2.3 eV to 2.2 eV. The intensities of the peaks obtained from PL spectra were strongly dependent on annealing time and confirmed the results obtained from UV-Vis. D.C. conductivity measurement showed that all the thin films have two differen
... Show MoreThe letter is defined as a message directed by the sender to another party, the future. The aim is to convey, clarify or explain a particular point or subject, and in the form of direct oral communication through speech that contains a set of words and words, The future can discuss the sender directly to exchange ideas with each other, or it may be written and in this case does not require direct interaction between the matchmaker and the recipient. As a result of the different sources and topics of the discourse, and the different types of categories addressed to the speech, and the number, it has been divided into several types.
And schools of discourse analysis emerged in the early eighties of the last century and has spread and ha
In this paper, an ecological model with stage-structure in prey population, fear, anti-predator and harvesting are suggested. Lotka-Volterra and Holling type II functional responses have been assumed to describe the feeding processes . The local and global stability of steady points of this model are established. Finally, the global dynamics are studied numerically to investigate the influence of the parameters on the solutions of the system, especially the effect of fear and anti-predation.
The research, entitled: "The Development Theory of Women's Empowerment in Islamic Sharia Law ", aims to show the means of human development for women through the texts of the Quran and Sunnah. It talked about the concept of human development for women, the goals of women's empowerment in legislative texts, the goals of human development in empowering women, the developmental aspect of women in the Sunnah of the Prophet, the integration of development in Islamic Sharia Law , and then the conclusion and sources.
The majority of statisticians, if not most of them, are primarily concerned with the theoretical aspects of their field of work rather than their application to the practical aspects. Its importance as well as its direct impact on the development of various sciences. Although the theoretical aspect is the first and decisive basis in determining the degree of accuracy of any research work, we always emphasize the importance of the applied aspects that are clear to everyone, as well as its direct impact on the development of different sciences. The measurements of public opinion is one of the most important aspects of the application of statistics, which has taken today, a global resonance and has become a global language that everyone can
... Show MoreThe art of Islamic ceramics is considered one of the main pillars of the art of ceramics in the plastic arts, as his knowledge of what is presented in the Islamic arts intertwined in a special way. And the Islamic ceramics are indications of fertility and the rekindling of religious ties, controversy over them, and interpretation as additions to their vocabulary. Studies in the plastic arts began to empty the knowledge towards this direction, especially its relationship to the Arabic calligraphy and specifically the Islamic decoration, which derived the first aesthetic values from calling the artist Muslim pottery and potters to inviting the Arabic letter and Islamic decoration to indicate within the theory of "displacement" the aestheti
... Show MoreThe current study examined the effect of different sample sizes to detect the Item differential functioning (DIF). The study has used three different sizes of the samples (300, 500, 1000), as well as to test a component of twenty polytomous items, where each item has five categories. They were used Graded Response Model as a single polytomous item response theory model to estimate items and individuals’ parameters. The study has used the Mantel-Haenszel (MH) way to detect (DIF) through each case for the different samples. The results of the study showed the inverse relationship between the sample size and the number of items, which showed a differential performer.
The current research aims at extracting the standard characteristics of the emotional balance of the university students according to the response theory. This was accomplished by following accredited scientific steps, to achieve this goal, the researcher followed scientific steps in the procedures of the analysis of the scale. She translated the scale from English to Arabic and then made a reverse translation. it was presented to a committee of experts in English to ensure and verify the validity of the paragraphs logically and prove the face validity of the scale, which consists of (30) paragraphs, it was presented to (6) experts who are specialists in the educational and psychological sciences and in the light of their observations ha
... Show MoreOBJECTIVE: Synthetic vertebral body replacement has been widely used recently to treat different spinal conditions affecting the anterior column. They arrange from trauma, infections, and even tumor conditions. In this study, we assess the functional outcome of this modality in different spinal conditions. PATIENTS AND METHODS: Thirty-six cases operated from October 2010 to December 2017. Twelve patients had spinal type A3 fractures, 11 cases with spinal tuberculosis (TB), and 13 cases with spinal tumors. They were followed clinically for a mean period of 2.4 years. RESULTS: All the cases were approached anteriorly. Seven cases had a post-operative infection. No neurological worsening reported. We had dramatic neurologic
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