Charakterizace tenkovrstvých elektroluminiscenčních součástek

Jádrem této disertační práce bylo studovat optické a elektrické charakteristiky tenkovrstvých elektroluminiscenčních součástek řízených střídavým proudem (ACTFEL) a zejména vliv procesu stárnutí luminiforů na jejich optické a elektrické vlastnosti. Cílem této studie měl být příspěvek ke zvýšení celkové účinnosti luminoforů, vyjádřené pomocí jasu, účinnosti a stability. Vzhledem k tomu, že současnou dominantní technologií plochých obrazovek je LCD, musí se další alternativní technologie plošných displejů porovnávat s LCD. Výhodou ACTFEL displejů proti LCD je lepší rozlišení, větší teplotní rozsah činnosti, větší čtecí úhel, či možnost čtení při mnohem vyšší intenzitě pozadí. Na druhou stranu je jejich nevýhodou vyšší energetická náročnost, problém s odpovídající barevností tří základních barev a podstatně vyšší napětí nutné pro činnost displeje. K dosažení tohoto cíle jsme provedli optická, elektrická a optoelektrická měření ACTFEL struktur a ZnS:Mn luminoforů. Navíc jsme studovali vliv dotování vrstvy pomocí KCl na chování mikrostruktury a na elektroluminiscenční vlastnosti (zejména na jas a světelnou účinnost) ZnS:Mn luminoforů. Provedli jsme i některá, ne zcela obvyklá, měření ACTFEL součástek. Vypočítali jsme i rozptylový poměr nabitých barevných center a simulovali transportní charakteristiky v ACTFEL součástkách. Studovali jsme vliv stárnutí dvou typů ZnS:Mn luminoforů (s vrstvou napařenou či získanou pomocí epitaxe atomových vrstev) monitorováním závislostí svítivost-napětí (L-V), velikost vnitřního náboje - elektrické pole luminoforu (Q-Fp) a kapacitance-napětí (C-V) ve zvolených časových intervalech v průběhu stárnutí. Provedli jsme krátkodobá i dlouhodobá měření a pokusili jsme se i o vizualizaci struktury luminoforu se subvlnovým rozlišením pomocí optického rastrovacího mikroskopu pracujícího v blízkém poli (SNOM). Na praktickém případu zeleného Zn2GeO4:Mn (2% Mn) ACTFEL displeje, pracujícího při 50 Hz, jsme také studovali stabilitu svítivosti pomocí měření závislosti svítivosti na napětí (L-V) a světelné účinnosti na napětí (eta-V). Přitom byl zhodnocen význam těchto charakteristik. Nezanedbatelnou a neoddělitelnou součástí této práce je i její pedagogický aspekt. Předložený text by mohl být využit i jako učebnice pro studenty na mé univerzitě v Lybii.The objective of this thesis is to study the optical and electrical characterization of Alternating-Current Thin-Film ElectroLuminescent (ACTFEL) devices, and specifically the aging process of phosphor materials that comprise the ACTFEL display in an effort to improve the overall performance of the primary phosphor colors in terms of brightness, efficiency and stability. Since the dominant flat-panel display technology is the LCD, an alternative flat-panel display technology must gauge itself in terms of the LCD. The advantages of ACTFEL displays in comparison with LCDs are the ability to pattern much smaller pixel, performance over a wider temperature range, full-viewing angle, and readability with much greater intensity background light. The disadvantages of ACTFEL displays against LCD ones are larger power consumption, lack of adequate chromaticity of the three primary colors, and much larger driving voltages. To achieve these objectives, the optical, electrical, and opto-electric measurements of the ACTFEL structures and ZnS:Mn phosphor hosts were carried out. Moreover, the effect of KCl co-doping on the microstructure and the electroluminescent properties (mainly brightness and luminous efficiency) of ZnS:Mn phosphors has been investigated, too. A non-common electrical characterization of ACTFEL devices has also been provided. We also calculated charged center scattering rates, and simulated the electron transport process in an ACTFEL device The study of the aging characteristics of evaporated and atomic layer epitaxy ZnS:Mn phosphors has been undertaken by monitoring the luminance-voltage (L-V) internal charge-phosphor field (Q-Fp) and capacitance-voltage (C-V) electrical characteristics at in selected time intervals during aging. Short-term and long-term ACTFEL aging studies has been provided and an attempt to visualize locally the structure of phosphor with a subwavelenght resolution using Scanning near-field optical microscope (SNOM) has also been presented. The practical case of a green Zn2GeO4:Mn (2% Mn) ACTFEL device operated at 50 Hz was studied and a luminance stability by a measurement of luminance-voltage (L-V) and luminous efficiency-voltage (eta-V) characteristics has been evaluated. A non-negligible and indiscreptible task of this thesis was also its pedagogical aspect. Therefore, the presented text can be considered as a textbook suitable for our students in Libya.

HAPS Gateway Link in the 5850-7075 MHz and Coexistence with Fixed Satellite Service

Gateway link is essential to connect HAPS platform to terrestrial based networks. This crucial link is incorporated in HAPS fixed service spectrum allocation in considerably high frequencies, renders the link for more attenuations by atmospheric gases, and rain effects, especially when the regional climate is not favorable. However, under the agenda item 1.20 of World Radio Conference-2012 (WRC-12) new HAPS allocation in the 5850-7075 MHz band is proposed. Although, spectrum features are incomparably reliable, on the contrary, Fixed Satellite Service (FSS) uplink transmissions will have signal levels much higher than those in HAPS systems and have the potential for causing interference at the HAPS gateway receiver. In this article a key aspect of co-channel interference phenomena is investigated to facilitate optimum frequency sharing in the band in question. By proposing mitigation techniques and statistical method this generic prediction model enhances the capability of the HAPS spectrum sharing and provides flexibility in spectrum planning for different fixed services

From accounting to economics: the role of aggregate special items in gauging the state of the economy

We propose and find that aggregate special items conveys more information about future real GDP growth than aggregate earnings before special items because the former contains advance news about future economic outcomes. A two-stage rational expectations test reveals that professional forecasters fully understand the information content of aggregate earnings before special items, but underestimate that of aggregate special items when revising their GDP forecasts. Using vector autoregressions, we show that aggregate earnings before special items has predictive ability for GDP because, as suggested by previous literature, it acts as a proxy for corporate profits included in national income. In contrast, aggregate special items captures changes in the behavior of economic agents on a timely basis, which, in turn, have real effects on firms' investment and hiring, as well as consumers' wealth and spending. Consistent with news-driven business cycles, we find that aggregate special items produces synchronized movements across macroeconomic aggregates

Population Density, Developmental Period and Fecundity of Anopheles Mosquito (Diptera: Culicidae) in the Gezira State, Sudan

In the Gezira State, insecticides were used for many years for controlling mosquitoes and other agricultural pests. The objective of this work was to study the population density, the developmental periods the reproductive periods and the fecundity of Anopheles mosquitoes in the Gezira State, Sudan. The study was conducted in three sites; Elmanagel, Elhosh and Wad Medani.Ten of one-day old or less of the cultured adult males and females of A. pharoensis wewe transferred separately to cage. The female pre-oviposition period, daily number of eggs deposited, the oviposition period, the post oviposition period, the adult longevity and the average number of eggs per female were recorded. The results revealed that, the number of A.arabiensis larvae collected from  the three sites was higher than that of A. pharoensis and A. funestus during the two seasons (2009 and 2010). The number of A. funestus adults collected at Wad Medani site during the two seasons was lowest than that collected from El Managel and El Hosh. The incubation period of the eggs, was relatively similar in all Anopheles species, as same as the larval period. The pupal period was relatively longer in A. funestus (2.4 days) and A. pharoensis (2.2 days) than in A.arabiensis (2 days). Adult A. pharoensis lived relatively longer (21 days) than A arabiensis and A. funestus (20 days). The total life cycle was relatively longer (32 days) in A. pharoensis than in A. arabiensis and A. funestus (30 days for each). Females of all species of Anopheles mosquito oviposited after one day from their emergence from the pupae and took also one day before they oviposit again. The oviposition period was significantly longer in A. arabiensis (3.3 days) than in A. pharoensis (2.5 days) and A. funestus (1.8 days). The oviposition rate was significantly higher in A. arabiensis (191) than in  A. pharoensis (150) and A. funestus (79). The fecundity of A. arabiensis (624 eggs/female) was significantly greater than that of A. pharoensis (391 eggs/female) and A. funestus (141 eggs/female). Such study should be run periodically for all sites in the Gezira State and neighboring States. &nbsp

Pyrrolizine-5-carboxamides: Exploring the impact of various substituents on the anti-inflammatory and anticancer activities

Towards optimization of the pyrrolizine-5-carboxamide scaffold, a novel series of six derivatives (4a-c and 5a-c) was prepared and evaluated for their anti-inflammatory, analgesic and anticancer activities. The (EZ)-7-cyano-6-((4-hydroxybenzylidene)amino)-N-(p-tolyl)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (4b) and (EZ)-6-((4-chlorobenzylidene)-amino)-7-cyano-N-(p-tolyl)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (5b) bearing the electron donating methyl group showed the highest anti-inflammatory activity while (EZ)-6-((4-chlorobenzylidene)amino)-7-cyano-N-phenyl-2,3-dihydro-1H-pyrrolizine-5-carboxamide (5a) was the most active analgesic agent. Cytotoxicity of the new compounds was evaluated against the MCF-7, A2780 and HT29 cancer cell lines using the MTT assay. Compounds 4b and 5b displayed high anticancer activity with IC50 in the range of 0.30–0.92 µmol L–1 against the three cell lines, while compound (EZ)-N-(4-chlorophenyl)-7-cyano-6-((4-hydroxybenzylidene)-amino)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (4c) was the most active against MCF-7 cells (IC50 = 0.08 µmol L–1). Both the anti-inflammatory and anticancer activities of the new compounds were dependent on the type of substituent on the phenyl rings. Substituents with opposite electronic effects on the two phenyl rings are preferable for high cytotoxicity against the MCF-7 and A2780 cells. COX inhibition was suggested as the molecular mechanism of the anti-inflammatory activity of the new compounds while no clear relationship could be observed between COX inhibition and anticancer activity. Compound 5b, the most active against the three cell lines, induced dose-dependent early apoptosis with 0.1–0.2 % necrosis in MCF-7 cells. New compounds showed promising drug-likeness scores while the docking study revealed high binding affinity to COX-2. Taken together, this study highlighted the significant impact of the substituents on the anti-inflammatory and anticancer activity of pyrrolizine-5-carboxamides, which could help in further optimization to discover good leads for the treatment of cancer and inflammation

Direct Extraction and Assessment of Genomic DNA of Mycetoma Fungi from Black-grains Specimen

Background: Direct isolation of genomic DNA of mycetoma fungi from black-grains achieve rapid diagnosis and may overcome culture disadvantages. Objectives: This study aimed to isolate and assess the DNA of mycetoma fungi using black-grains and to apply amplification of ITS region and nucleotide sequences. Methods: CTAB method was followed by manual homogenization alternatively to liquid nitrogen and glass beads disruption to obtain the genomic DNA. Results: Yielded DNA concentrations vary from 1.50 to 47.97 μg/ml (mean 10.09 μg/ml) while the optimum DNA purity recorded with 75.8% of specimens (n=69/91).Successful amplification of ITS region was done using pan-fungal primers (ITS4/5) with 90.1 (n=82/91)percentage. Species nucleotide sequences were detected with 67 (94.4%) amplicons from a total of 71.Conclusion: The study recommended using of black-grain specimens for DNA extraction of mycetoma fungi parallel with culture to insure rabid diagnosis and identification

ART-Owen Scrambling

We present a novel algorithm for implementing Owen-scrambling, combining the generation and distribution of the scrambling bits in a single self-contained compact process. We employ a context-free grammar to build a binary tree of symbols, and equip each symbol with a scrambling code that affects all descendant nodes. We nominate the grammar of adaptive regular tiles (ART) derived from the repetition-avoiding Thue-Morse word, and we discuss its potential advantages and shortcomings. Our algorithm has many advantages, including random access to samples, fixed time complexity, GPU friendliness, and scalability to any memory budget. Further, it provides two unique features over known methods: it admits optimization, and it is invertible, enabling screen-space scrambling of the high-dimensional Sobol sampler.Comment: To appear at SIGGRAPH Asia 202

Palate of turkey (Meleagris gallopavo): Gross Anatomical, Light and Scanning Electron Microscopical Study

This investigation aimed to determine the morphological characteristics of the palate of bronze black turkey by gross anatomy, light and scanning electron microscopy. The oral roof (palate) constitutes 87.73% of the oropharyngeal roof length, comprising two parts; rostral and caudal. The rostral part of is characterized by the presence of median palatine ridge, rostral and caudal lateral palatine ridges, narrow part of the choanal slit and three rows of palatine papillae. The median palatine ridge shows rostral continued and caudal interrupted parts. This ridge as shown by scanning electron microscopy (SEM) bears 4-5 transverse furrows at the level of the beginning of the caudal lateral palatine ridges. Numerous Periodic Acid-Schiff (PAS)-positive compound tubular mucous maxillary, palatine and sphenopterygoid salivary glands are distributed in the mucosa of the palate. From all above mentioned, it's clear that the palate in turkey reveals some different anatomical features in compared with that of the other birds

Morphological Studies on the Upper Beak of Turkey (Meleagris gallopavo)

This study was carried out to provide a detailed description about the upper beak of turkey, regarding its gross anatomical, light and scanning electron microscopic morphology. The upper beak extends in a hook like infront of the lower beak. It measures 53.80 mm long. The height and width of the upper beak increase caudalwards. SEM shows that the tip and the lateral sides of the upper beak are covered with numerous flakes of keratin. At the free tip of the beak, these keratinized flakes have an irregular appearance which may be due to desquamation of the epithelium during manipulation of foods. Immediately in front of the angle of the mouth, the lateral edge of the upper beak is characterized by the presence of transverse furrows which giving it a serrated appearance. The upper beak of the turkey consists of a bony support covered by dermal and epidermal layers