947 resultados para Local electronic structures


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Ива Р. Докузова, Димитър Р. Разпопов - В настоящата статия е разгледан клас V оттримерни риманови многообразия M с метрика g и два афинорни тензора q и S. Дефинирана е и друга метрика ¯g в M. Локалните координати на всички тези тензори са циркулантни матрици. Намерени са: 1) зависимост между тензора на кривина R породен от g и тензора на кривина ¯R породен от ¯g; 2) тъждество за тензора на кривина R в случая, когато тензорът на кривина ¯R се анулира; 3) зависимост между секционната кривина на прозволна двумерна q-площадка {x, qx} и скаларната кривина на M.

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The emergence of innovative and revolutionary Integration Technologies (IntTech) has highly influenced the local government authorities (LGAs) in their decision-making process. LGAs that plan to adopt such IntTech may consider this as a serious investment. Advocates, however, claim that such IntTech have emerged to overcome the integration problems at all levels (e.g. data, object and process). With the emergence of electronic government (e-Government), LGAs have turned to IntTech to fully automate and offer their services on-line and integrate their IT infrastructures. While earlier research on the adoption of IntTech has considered several factors (e.g. pressure, technological, support, and financial), inadequate attention and resources have been applied in systematically investigating the individual, decision and organisational context factors, influencing top management's decisions for adopting IntTech in LGAs. It is a highly considered phenomenon that the success of an organisation's operations relies heavily on understanding an individual's attitudes and behaviours, the surrounding context and the type of decisions taken. Based on empirical evidence gathered through two intensive case studies, this paper attempts to investigate the factors that influence decision makers while adopting IntTech. The findings illustrate two different doctrines - one inclined and receptive towards taking risky decisions, the other disinclined. Several underlying rationales can be attributed to such mind-sets in LGAs. The authors aim to contribute to the body of knowledge by exploring the factors influencing top management's decision-making process while adopting IntTech vital for facilitating LGAs' operational reforms.

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Saudi Arabian Small and Medium Enterprises (SMEs) will face fierce competition from new entrants to local markets as a result of their accession to the Word Trade Organisation (WTO), and electronic commerce (e-commerce) technologies can reinforce SME's competitive edge. This study investigates the state of e-commerce adoption and analyses the factors that determine the extent to which SMEs in Saudi Arabia are inclined towards deploying e-commerce technologies. This could assist future firms in designing effective implementation projects. Seven SMEs' e-commerce adoption levels are studied as a case. The Technology-Organization-Environment (TOE) framework was used as the major source of inspiration in our analysis of e-commerce adoption amongst Saudi SMEs. In addition to advancing research on e-commerce in Saudi Arabia, this chapter also highlights several directions for future inquiry and implications for managers and policymakers.

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The strong couplings between different degrees of freedom are believed to be responsible for novel and complex phenomena discovered in transition metal oxides (TMOs). The physical complexity is directly responsible for their tunability. Creating surfaces/interfaces add an additional ' man-made' twist, approaching the quantum phenomena of correlated materials. ^ The dissertation focused on the structural and electronic properties in proximity of surface of three prototype TMO compounds by using three complementary techniques: scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and low energy electron diffraction, particularly emphasized the effects of broken symmetry and imperfections like defects on the coupling between charge and lattice degrees of freedom. ^ Ca1.5Sr0.5RuO4 is a layered ruthenate with square lattice and at the boundary of magnetic/orbital instability in Ca2-xSrxRuO4. That the substitution of Sr 2+ with Ca2+ causing RuO6 rotation narrows the dxy band width and changes the Fermi surface topology. Particularly, the γ(dxy) Fermi surface sheet exhibited hole-like in Ca1.5Sr0.5RuO4 in contrast to electron-like in Sr2RuO4, showing a strong charge-lattice coupling. ^ Na0.75CoO2 is a layered cobaltite with triangular lattice exhibiting extraordinary thermoelectric properties. The well-ordered CoO2-terminated surface with random Na distribution was observed. However, lattice constants of the surface are smaller than that in bulk. The surface density of states (DOS) showed strong temperature dependence. Especially, an unusual shift of the minimum DOS occurs below 230 K, clearly indicating a local charging effect on the surface. ^ Cd2Re2O7 is the first known pyrochlore oxide superconductor (Tc ∼ 1K). It exhibited an unusual second-order phase transition occurring at TS1 = 200 K and a controversial first-order transition at TS2 = 120 K. While bulk properties display large anomalies at TS1 but rather subtle and sample-dependent changes at TS2, the surface DOS near the EF show no change at T s1 but a substantial increase below TS2---a complete reversal as the signature for the transitions. We argued that crystal imperfections, mainly defects, which were considerably enhanced at the surface, resulted in the transition at TS2. ^

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Electronic noise has been investigated in AlxGa1−x N/GaN Modulation-Doped Field Effect Transistors (MODFETs) of submicron dimensions, grown for us by MBE (Molecular Beam Epitaxy) techniques at Virginia Commonwealth University by Dr. H. Morkoç and coworkers. Some 20 devices were grown on a GaN substrate, four of which have leads bonded to source (S), drain (D), and gate (G) pads, respectively. Conduction takes place in the quasi-2D layer of the junction (xy plane) which is perpendicular to the quantum well (z-direction) of average triangular width ∼3 nm. A non-doped intrinsic buffer layer of ∼5 nm separates the Si-doped donors in the AlxGa1−xN layer from the 2D-transistor plane, which affords a very high electron mobility, thus enabling high-speed devices. Since all contacts (S, D, and G) must reach through the AlxGa1−xN layer to connect internally to the 2D plane, parallel conduction through this layer is a feature of all modulation-doped devices. While the shunting effect may account for no more than a few percent of the current IDS, it is responsible for most excess noise, over and above thermal noise of the device. ^ The excess noise has been analyzed as a sum of Lorentzian spectra and 1/f noise. The Lorentzian noise has been ascribed to trapping of the carriers in the AlxGa1−xN layer. A detailed, multitrapping generation-recombination noise theory is presented, which shows that an exponential relationship exists for the time constants obtained from the spectral components as a function of 1/kT. The trap depths have been obtained from Arrhenius plots of log (τT2) vs. 1000/T. Comparison with previous noise results for GaAs devices shows that: (a) many more trapping levels are present in these nitride-based devices; (b) the traps are deeper (farther below the conduction band) than for GaAs. Furthermore, the magnitude of the noise is strongly dependent on the level of depletion of the AlxGa1−xN donor layer, which can be altered by a negative or positive gate bias VGS. ^ Altogether, these frontier nitride-based devices are promising for bluish light optoelectronic devices and lasers; however, the noise, though well understood, indicates that the purity of the constituent layers should be greatly improved for future technological applications. ^

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My dissertation is the first project on the Haitian Platform for Advocacy for an Alternative Development- PAPDA, a nation-building coalition founded by activists from varying sectors to coordinate one comprehensive nationalist movement against what they are calling an Occupation. My work not only provides information on this under-theorized popular movement but also situates it within the broader literature on the postcolonial nation-state as well as Latin American and Caribbean social movements. The dissertation analyzes the contentious relationship between local and global discourses and practices of citizenship. Furthermore, the research draws on transnational feminist theory to underline the scattered hegemonies that intersect to produce varied spaces and practices of sovereignty within the Haitian postcolonial nation-state. The dissertation highlights how race and class, gender and sexuality, education and language, and religion have been imagined and co-constituted by Haitian social movements in constructing ‘new’ collective identities that collapse the private and the public, the rural and the urban, the traditional and the modern. My project complements the scholarship on social movements and the postcolonial nation-state and pushes it forward by emphasizing its spatial dimensions. Moreover, the dissertation de-centers the state to underline the movement of capital, goods, resources, and populations that shape the postcolonial experience. I re-define the postcolonial nation-state as a network of local, regional, international, and transnational arrangements between different political agents, including social movement actors. To conduct this interdisciplinary research project, I employed ethnographic methods, discourse and textual analysis, as well as basic mapping and statistical descriptions in order to present a historically-rooted interpretation of individual and organizational negotiations for community-based autonomy and regional development.

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The growth of international tourism and the attendant economic benefits to the world nations, has been phenominal since the end of the second world war. It is considered that the industry's upsurge will continue even in the phase of various constraints exemplified in high fuel cost, constant increase in fares and the threatening world-wide recessions. Developed as well as developing countries have gained substantially from the industry. A recent development shows increasing tourist traffic towards developing countries, while developed countries still hold their fort in stable growth of tourist receipts. The strategic beneficial effects of international tourist industry are often quantified in terms of foreign exchange earnings, employments offered, and the Real Estate super-structures; but in general,the industry has innumerable direct and indirect benefits to any nation engaging in the trade. The objective of this thesis is to demonstrate by comparative analysis and proven parameters that the international tourist industry which is given low priority in development in Nigeria, can equally contribute to the nation's economic growth as other industrial sectors which receive high priority and patronage in development. The data for this paper are gathered from primary sources which are i) responses by the Federal and State Governments' tourism-related offices; ii) government publications e.a. the Third National Development Plan of Federal Republic of Nigeria; and iii) Books and collections. The secondary sources include reports,periodicals and hospitality industry publications. To formally establish the international tourist industry in Nigeria, all the governments (Federal, State and Local) and the private sector in the country, should commence the development of the industry with research and feasibility studies, to be followed by proper planning at all levels and based on the result of the research and feasibility studies.

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Two protected areas: Royal Bardia National Park (RBNP) and Royal Suklaphanta Wildlife Reserve (RSWR) in the Western Terai, Nepal, are under threats due to present political turmoil, uncontrolled immigration, inefficient land reform policies and unsustainable resource use. I did a stratified random questionnaire survey of 234 households to determine how resource use patterns and problems influence conservation attitudes. Chi-square, Student's t, Mann-Whitney and Kruskal-Wallis tests, and multiple regression were used. There was spatio-temporal variability in resource use patterns and dependency. People were collecting eight and seven types of resources in RBNP and RSWR, respectively. However, people in RBNP were more dependent on resources than RSWR. In both areas, the problem of firewood is serious. The mean attitude score of RBNP (8.4 ± 1.44) was significantly higher than the score of RSWR (7.7 ± 1.66; t = 3.24, p = 0.0007). Conservation attitude was determined by variables such as participation in trainings, wildlife damage, and satisfaction towards user groups.

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This thesis explores how architecture can adapt local vernacular design principles to contemporary building design in a rural setting. Vernacular buildings in Guyana present a unique and coherent set of design principles developed in response to climatic and cultural conditions. The concept of “habitus” proposed by philosopher Pierre Bourdieu describing the evolving nature of social culture was used to interpret Guyanese local buildings. These principles were then applied to the design of a Women’s Center in the village of Port Mourant on the east coast of Guyana. The design specifically interpreted the “bottom-house” of local Guyanese architecture, an inherently flexible transitional outdoor space beneath raised buildings. The design of the Women’s Center demonstrates how contemporary architectural design can respond to climatic requirements, local preferences and societal needs to support the local culture.

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Inscription: Verso: New York.

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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

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Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.