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The influence of temperature and size on the absorption coefficient of CdSe quantum dots
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Abstract<p>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<sup>−1</sup>(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.</p>
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Publication Date
Sat Oct 01 2016
Journal Name
Journal Of Educational And Psychological Researches
Teaching methods approved in the university and its relationship to classroom discipline and management proposals treated
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The study aims detection teaching modalities adopted relationship in Jerash University exactly the classroom, and to achieve the goal of the study was to develop a questionnaire consisting of (39) items, and was achieving validity and reliability have, then sent to a sample of professors made up the university from (122) university professor of the total (172) professor, and they study population.

     Study found a relationship between the teaching methods of the four their strategies with classroom management, and as a result the overall average level, while Hspt critical thinking at the highest correlation with classroom discipline management relationship strategy, while the relatio

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Publication Date
Wed Nov 29 2023
Journal Name
International Journal Of Pharmaceutical And Bio-medical Science
H. Pylori and Autoimmune Disorders: Unraveling the Links between Chronic Infection and Immune Dysfunction: Review Paper
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The human stomach is home to the Gram-negative bacterium Helicobacter pylori, which has been connected to several gastrointestinal disorders. There may be a link between H. pylori infection and the start of autoimmune disorders, according to recent research. This review examines the intricate connections between persistent H. pylori infection, immune system dysregulation, and their possible role in initiating autoimmune disorders. The study begins with a summary of H. pylori infection and its prevalence worldwide, emphasizing the mounting data that connects this bacterium to autoimmune disorders. Then, using experimental data from animal models and epidemiological research as support, it undertakes a thorough review of autoimmune di

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Publication Date
Fri Nov 15 2024
Journal Name
Iraqi Journal Of Science
Identify the differences between ordinary and barred spiral galaxies, NGC 2649 and NGC 4662 for examples
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Since the beginning of mankind, the view of the sky was present through observations with the naked eye, then it developed with time, and the sciences and tools of astronomical observations developed, including photometric measurements, which reached a high degree of accuracy in describing various cosmic phenomena, including the study of galaxies, their composition, and the differences between them, and from here the importance of this study emerged, to determine the differences between two distinct types of classification of galaxies, which are normal and barred spiral galaxies, where two galaxies NGC 4662 and NGC 2649 were chosen that represented certain types of galaxies to study the morphological structure of the two galaxies, a

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Publication Date
Sat Jul 18 2020
Journal Name
College Of Islamic Sciences
Facilitating Tributaries (Supporters) in the Differences between Al Dhadhiya and Al Dhaiya": Dhadhiya and Al Dhaiya"
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   الضاد والظاء موطن تفرد العربية وفخرها ، الفت فيهما العشرات والعشرات من المصنفات الثرّة لكثرة ذرائع تلابسهما والخلط بينهما ، فهما متشابهان في هيكل البناء ، وإخراجهما متداخل على اللسان ، وألفاظهما متناظرة برحابة في الإملاء ، فضلاعن  اشكالهما  إلى حدّ الآن ، مما حثني على التفكير في وسائل تسهل المطروح وتمد جسراً بين أجزائه عسى أن تدنو قطافه في دفع الشبهة ومواراتها ، فتحصلت لي امور ادرتها بكلمتين مف

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Publication Date
Fri Mar 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Emotional Trends, and Emotional Exhaustion in organizations: (Developing foundations the philosophy and thinking in organizational behavior)
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Emotional exhaustion considered one of the critical factors in the formation and composition of organizational behavior of individuals within organizations, as well as social behavior and psychological, and emotional exhaustion is one of the three components of burnout, as well as depersonalization (cynicism) and low achievement, the emergence of research relevant to this concept began at the beginning of the seventies of the twentieth century, then started to become clear features in the eighties it. This research aims to build intellectual framework for draining emotional exhaustion through highlight on most important philosophical contents, as well as review and analysis of some models associated with this concept, and then a

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Publication Date
Fri Dec 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
The relationship between foreign direct investment and economic growth in Iraq after 2003(reality and ambition)
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Foreign direct investment is considered one of important bases to blind economy for many. Countries as if the main stage for developing national economy ,so for this ,many of countries give great prominence to the role of drivel foreign investment due to its importance as one of economic growth pillars in the developing countries. They offer a support for modern technology, organizational and managerial skills.        

  Dneto the importance of direct foreign investment on the economic growth, today, we discover that Iraq in need to rebnlid the in frastructuve and renew what has been destroyed during was in many production and export institutions . as wel

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Publication Date
Sun Dec 27 2020
Journal Name
Journal Of The College Of Education For Women
Digital Citizenship and its Relationship to the Level of Health Awareness of Corona Virus (Covid-19) among a Sample of Palestinian University Students: محمود عبد المجيد عساف
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The study aims to identify the degree of appreciation for the level of digital citizenship of a sample of Palestinian university students in the governorates of Gaza, and its relationship to the level of health awareness about the emerging coronavirus (covid-19). To achieve the objectives of the study, the researcher followed a descriptive approach by applying two questionnaires; the first, which consists of 30 items, was used  to measure the level of digital citizenship.  The second, which consists of 19 items, was used to measure the level of health awareness. Both questionnaires  were applied on a sample of 367 students who were electronically selected using the manner simple randomness. Results have shown that the degr

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Publication Date
Sun Sep 01 2019
Journal Name
Journal Of Global Pharma Technology
Calculation of Stabilization Energy of Tetrahedrane with its Nitrogen Substituted Derivatives by DFT Method and Driving an Empirical Relation Connect it with Charge Functions of the Molecule
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In this work the strain energy of tetrahedrane and its nitrogen substituted molecules were calculated by isodesmic reaction method according to DFT quantum chemical fashion, the used basis set was 6-31G/B3-LYP, in addition all structures were optimized by RM1 semi-empirical method. From the obtained data we estimate an empirical equation connect between strain energy of the molecule with charge functions represented by dipole moment of the molecule plus accumulated charge density involved within the tetrahedron frame plus the number of nitrogen atoms. The results indicate the charge spreading factors by polarization and processes are the most important factors in decreasing the strain energy.

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Publication Date
Sun Mar 01 2020
Journal Name
Indian Journal Of Forensic Medicine & Toxicology
Determination of Some Volatile Organic Compounds in the water produced at Al-Ahdab oilfield in the Governorate of Wasit, Iraq using Headspace SPE-GC-FID
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The study was conducted over the period of Oct 2018 to Apr 2019 and is aimed for the detection and estimation of four hazardous Volatile Organic Compounds VOC (benzene, toluene, ethylbenzene, and xylene) so-called (BTEX) in samples collected from the produced water in the Al-Ahdab oil field in Iraq also to track their availability in the important natural water sources around the field. These compounds pose a risk to human health as well as environment. To avoid the laborious and tiresome conventional extraction methods, water samples were collected and concentrated using solid-phase extraction technique (SPE) which is a robust and cost-effective method of sample extraction with minimal exposure and handling of solvents and then to be analy

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Scopus
Publication Date
Sun Jan 01 2023
Journal Name
The International Tinnitus Journal
Does the Location of a Small Tympanic Membrane Perforation Affect the Degree of Hearing Loss in Adult Patients with Inactive Mucosal Chronic Suppurative Otitis Media?
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