Bragg Reflectors consist of periodic dielectric layers having an optical path length of quarter wavelength for each layer giving them important properties and makes them suitable for optoelectronics applications. The reflectivity can be increased by increasing the number of layers of the mirror to get the required value. For example for an 8 layers Bragg mirror (two layers for each dielectric pair), the contrast of the refractive index has to be equal to 0.275 for reaching reflectivity > 99%. Doubling the number of layers results in a reflectivity of 99.99%. The high reflectivity is purely caused by multiple-interference effects. It can be analyzed by using different matrix methods such as the transfer matrix method (TMM) which is the simplest method to study the characteristic of devices with different alternating layers.
Physical and chemical adsorption analyses were carried out by nitrogen gas using ASTM apparatus at 77 K and hydrogen gas using volumetric apparatus at room temperature, respectively. These analyses were used to determine the effect of coke deposition and poisoning metal on surface area, pore size distribution, and metal surface area of fresh and spent hydrodesulphurization catalyst Co-Mo\Al2O3 . Samples of catalyst (fresh and spent) used in this study are taken from AL-Dura refinery. The results of physical adsorption shows that surface area of spent catalyst reduced to third compare with fresh catalyst and these catalysts exhibit behavior of type four according to BET classification ,so, the pores of these samples are cylindrical, an
... Show MoreIn this paper we will study some of the properties of an operator by looking at the associated S-act of this operator, and conversely. We look at some operators, like one to one operators, onto operators. On the other hand, we look at some act theoretic concepts, like faithful acts, finitely generated acts, singular acts, separated acts, torsion free acts and noetherian acts. We try to determine what properties of T make the associated S-act has any of these properties.
The element carbon Carbon dioxide emissions are increasing primarily as a result of people's use of fossil fuels for electricity. Coal and oil are fossil fuels that contain carbon that plants removed from the atmosphere by photosynthesis over millions of years; and in just a few hundred years we've returned carbon to the atmosphere. The element carbon Carbon dioxide concentrations rise primarily as a result of the burning of fossil fuels and Freon for electricity. Fossil fuels such as coal, oil and gas produce carbon plants that were photosynthesized from the atmosphere over many years, since in just two centuries, carbon was returned to the atmosphere. Climate alter could be a noteworthy time variety in weather designs happening ov
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The objective behind this work was to find out the bacteriological profile of post burn infections in wound. The study was carried out from December 2010 to February 2011 at the Burns Unit of Al –Kindy Hospital and Al-Yarmook Hospital in Baghdad. Sixty burn patients have been investigated for bacterial profile of burn wound infections. Specimens were collected in the form of wound swabs. The organisms were isolated and identified by standard microbiological methods. Antimicrobial susceptibility test has been done by ATB-PSE5 kit(BioMereiux). Pseudomonas aeruginosa 35(58.3 %) was found to be the most common isolate followed by Klebsiella pneumonae 10(16.6%), Staphylococcus aureus 7(10%). ,E.coli 3(5%), Proteus merabilis 1(1.6 %), others 2
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The current research aims to identify the self-regulation of university students, as well as to identify the significance of the difference in self-regulation according to the variable of sex (male-female), specialization (scientific-human), and grade (first-fourth). To achieve the research objectives, the two researchers developed a scale of (28) items about self-regulation According to the theory of (Pandora, 1991). The scale was administered to (500) students from the first and fourth stages of Al -Mustansiriyah University who were selected based on the random stratification method for the 2020/2021 academic year. The results showed that university students have a good level of self-regulation. There are no significant differences in
... Show MoreDuring this research accomplish some chemical modifications on the Poly for new modified polymers with Kimaaaúah qualities, physical and unexpected new applications that the first of these chemical modifications that was completed is the introduction of a poly styrene butadiene swash and then this group
With the emergence of globalization, international and diplomatic relations have developed among countries and led to the creation of new words, concepts and diplomatic terminology. The purpose of this thesis is to study and analyze the types of written, oral and nonverbal diplomatic language and to shed light on the types of diplomatic translation/interpretation. In addition to that, the thesis investigates the role of translator/interpreter when translating diplomatic texts and interpreting diplomatic speeches in international conferences, organizations, etc. It also tackles the difficulties faced during translation/interpretation and how to overcome these problems and find appropriate solutions for them. The main purpose of this thesi
... Show MoreThis work reports thirty three Iraqi species and one subspecies of Hydrophilidae, distributed in eleven genera under four subfamilies. Of them two species namely Laccobius gracilis Motsch and Laccobius syriacus Guilleb. Are new records for Iraq. The locality data were mentioned for each species.
drosophila larvare of diffrent speces were subjected to this in order study the structure of cephalopharyngeal armature and mouth more hooks dentition the lines number among