Because of Cadmium selenide quantum dots (CdSe quantum dots) has a tuning energy gap in the visible light range, therefore; it is provided a simple theoretical model for the absorption coefficient of CdSe quantum dots, where the absorption coefficient determines the extent to which the light of a material can penetrate a specific wavelength before it is absorbed. CdSe quantum dots have an energy gap can be controlled through two effects: the temperature and the dot size of them. It is found that; there is an absorption threshold for each directed wavelength, where CdSe quantum dots begin to absorb the visible spectrum at a size of 1.4 nm at room temperature for a directed wavelength 300 nm. It has been observed that; when the wavelength is increasing its absorption threshold is increased. For wavelengths (400, 500, 600) nm, the absorption thresholds for each quantum sizes are (1.8, 2.2. 3.2)nm respectively. On the other hand, a rising of the temperature led to reduces the absorption coefficient value, that at 400 K for all quantum sizes, the absorption coefficient increases >2000cm−1(According to the directed wavelength) than it is at 0 K. CdSe quantum dots can be considered as one of the most promising materials because it has a tuning gap for the visible wavelengthsfor different applications, such as light-emitting diodes in different colors of the visible spectrum. It is found that; there is a good agreement between our theoretical calculations and experimental results.
Mechanism of Arbitration in the Stock Exchange Disputes
Objectives To quantify the reproducibility of the drill calibration process in dynamic navigation guided placement of dental implants and to identify the human factors that could affect the precision of this process in order to improve the overall implant placement accuracy. Methods A set of six drills and four implants were calibrated by three operators following the standard calibration process of NaviDent® (ClaroNav Inc.). The reproducibility of the position of each tip of a drill or implant was calculated in relation to the pre-planned implants’ entry and apex positions. Intra- and inter-operator reliabilities were reported. The effects of the drill length and shape on the reproducibility of the calibration process were also investig
... Show MoreBackground: Goiter is one of the most common conditions that affect people’s at different age groups with its effect on the metabolic status of the body through the hyper&/hypo functioning gland that may needs surgical resection. This prospective study had been conducted on 100 patient (85 females&15 males} at the specialized center for endocrinology and diabetes mellitus in Baghdad city, between Jan.2013-Oct.2014;Their ages were ranging between 11-75 years ; the median age is (40.5 years) .Objectives: define the clinic-pathological pattern of goiter in the center .Methods: This is a prospective study at the specialized center for endocrinology & diabetes in Baghdad at ALRissafa district; including 100 patients (84 f
To investigate the relationship between increased lipid peroxidation, and the lowering of both plasma total proteins and albumin in lead-exposed workers, and the effectiveness of antioxidants (vit. C and E) in modulating oxidative stress in those workers.
Thirty male and females workers employed in the Iraqi storage battery (age range 20-40 years) were participating in this study. Additionally, 11 healthy subjects were served as healthy controls, with the same age range compared to workers group, to avoid the effects of age variations on the studied parameters. Blood lead levels, erythrocytes and plasma MDA, erythrocytes and plasma GSH, total protein and albumin levels in healthy controls and lead-exposed workers pre- and post-tr
... Show MoreThe Sacrament of Marriage in the Christian Religion
في بداية الستينيات ظهرت شبكة الإنترنت لاستعمالها في أغراض غير تجارية ، ثم تطورت بشكل مذهل خلال السنوات الأخيرة، فبعد أن كانت مجرد شبكة صغيرة أصبحت الآن تضم ملايين المستخدمين حول العالم ، وتحولت من مجرد شبكة بحث أكاديمي إلى بيئة متكاملة للاستثمار والعمل والإنتاج والإعلام والحصول على المعلومات .
وفي بداية تأسيس الشبكة لم يكن ثمة اهتمام بمسائل الأمن بقدر ما كان الاهتمام ببنائها وتوسيع نش
... Show MoreEducation is the most powerful and important weapon in fighting poverty and unemployment because it provides students with new skills that appropriate the new market requirements and fair distribution of natural resources. It also transfers knowledge, skills, and ethics over generations. Education aims to create effective leaders who go under training and rehabilitation process, create a new human and instill faith, generate the creativity and innovation, and keep abreast with scientific process, updating curriculum, and finally, applying the technical education
Abstract
Balance is a psychological need and a requirement of importance as the individual seeks to maintain it. The research problem is summarized in the question: do students in the kindergarten department have a cognitive balance? The research aims to identify the cognitive balance of students in the kindergarten department and to identify if there are differences among students of the four stages according to the cognitive balance. The research community was limited to the students in the kindergarten department at the University of Baghdad / College of Education for Women and Al-Mustansiriya University / College of Basic Education and Iraqi University / College of Education for Women for the academic y
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