852 resultados para Video game studies
Resumo:
Ab initio density functional calculations were performed to study the geometry and electronic structure of a prototypical zigzag AlN nanoribbon. We find that H-terminated zigzag 10-AlN nanoribbons have a non-direct band gap and are nonmagnetic. When a transverse electric field is applied, the band gap decreases monotonically with the strength of field E. Zigzag AlN nanoribbons with the N edge unpassivated display strong spin-polarization close to the Fermi level, which will result in spin-anisotropic transport. These results suggest potential applications for the development of AlN nanoribbon-based nanoelectronics applications.
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Structural and electronic properties have been studied for Boron Nitride nanoribbons (BNNR) with both zigzag and armchair shaped edge (Z-BNNR and A-BNNR) by first-principle spin-polarized total energy calculations. We found that the energy band gap of Z-BNNR is indirect and decreases monotonically with the increasing ribbon width, whereas direct energy band gap oscillation was observed for A-BNNRs. Additionally, C-substitution at either single boron or nitrogen atom site in BNNRs could induce spontaneous magnetization. Our results could be potentially useful to design magnetic nano-devices based on BNNRs.
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Ab initio density functional theory (DFT) calculations are performed to study the formation and diffusion of hydrogen vacancies on MgH2(110) surface and in bulk. We find that the formation energies for a single H-vacancy increase slightly from the surface to deep layers. The energies for creating adjacent surface divancacies at two inplane sites and at an inplane and a bridge site are even smaller than that for the formation of a single H-vacancy, a fact that is attributed to the strong vacancy−vacancy interactions. The diffusion of an H-vacancy from an in-plane site to a bridge site on the surface has the smallest activation barrier calculated at 0.15 eV and should be fast at room temperature. The activation barriers computed for H-vacancy diffusion from the surface into sublayers are all less than 0.70 eV, which is much smaller than the activation energy for desorption of hydrogen on the MgH2(110) surface (1.78−2.80 eV/H2). This suggests that surface desorption is more likely than vacancy diffusion to be rate determining, such that finding effective catalyst on the MgH2 surface to facilitate desorption will be very important for improving overall dehydrogenation performance.
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The low index Magnesium hydride surfaces, MgH2(0 0 1) and MgH2(1 1 0), have been studied by ab intio Density Functional Theory (DFT) calculations. It was found that the MgH2(1 1 0) surface is more stable than MgH2(0 0 1) surface, which is in good agreement with the experimental observation. The H2 desorption barriers vary depending on the crystalline surfaces that are exposed and also the specific H atom sites involved – they are found to be generally high, due to the thermodynamic stability of the MgH2 system, and are larger for the MgH2(0 0 1) surface. The pathway for recombinative desorption of one in-plane and one bridging H atom from the MgH2(1 1 0) surface was found to be the lowest energy barrier amongst those computed (172 KJ/mol) and is in good agreement with the experimental estimates.
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From the early-to-mid 2000s, the Australian horror film production sector has achieved growth and prosperity of a kind not seen since its heyday of the 1980s. Australian horror films can be traced back to the early 1970s, when they experienced a measure of commercial success. However, throughout the twenty-first-century Australian horror gained levels of international recognition that have surpassed the cult status enjoyed by some of the films in the 1970s and 1980s. In recent years, Australia has emerged as a significant producer of breakout, cult, and solid B-grade horror films, which have circulated in markets worldwide. Australian horror’s recent successes have been driven by one of its distinguishing features: its international dimensions. As this chapter argues, the Australian horror film production sector is an export-oriented industry that relies heavily on international partnerships and presales (the sale of distribution rights prior to a film’s completion), and on its relationships with overseas distributors. Yet, these traits vary from film to film as the sector is comprised of several distinct domains of production activity, from guerrilla films destined for niche video markets like specialist cult video stores and online mail-order websites to high(er)-end pictures made for theatrical markets. Furthermore, the content and style of Australian horror movies has often been tailored for export. While some horror filmmakers have sought to play up the Australianness of their product, others have attempted to pass off their films as faux-American or as placeless films effaced of national reference points.
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Literacy studies have begun to examine the spatial dimension of literacy practices in a way that foregrounds space, and that considers space as constitutive to human relations and practices. This chapter provides an introduction to spatial literacy research, providing a guide to key theorists, themes, and studies that have shaped historical and new developments in spatial approaches to literacy practice and pedagogy. It begins by reconceptualising socio-spatial approaches to literacy research and defines terms. Intersections with related social theories are examined, with an emphasis on critical approaches and the politics of space. It clarifies the relationship between socio-spatial and socio-cultural paradigms, revisiting the spatial in seminal socio-cultural research. It covers new ground,including networks, flows, and deterritorialisation of literacy practice. The chapter concludes with challenges and recommendations for future language research and educational practice.
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Matched case–control research designs can be useful because matching can increase power due to reduced variability between subjects. However, inappropriate statistical analysis of matched data could result in a change in the strength of association between the dependent and independent variables or a change in the significance of the findings. We sought to ascertain whether matched case–control studies published in the nursing literature utilized appropriate statistical analyses. Of 41 articles identified that met the inclusion criteria, 31 (76%) used an inappropriate statistical test for comparing data derived from case subjects and their matched controls. In response to this finding, we developed an algorithm to support decision-making regarding statistical tests for matched case–control studies.
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KEEP CLEAR pavement markings are widely used at urban signalised intersections to indicate to drivers to avoid entering blocked intersections. For example, ‘Box junctions’ are most widely used in the United Kingdom and other European countries. However, in Australia, KEEP CLEAR markings are mostly used to improve access from side roads onto a main road, especially when the side road is very close to a signalised intersection. This paper aims to reveal how the KEEP CLEAR markings affect the dynamic performance of the queuing vehicles on the main road, where the side road access is near a signalised intersection. Raw traffic field data was collected from an intersection at the Gold Coast, Australia, and the Kanade–Lucas–Tomasi (KLT) feature tracker approach was used to extract dynamic vehicle data from the raw video footage. The data analysis reveals that the KEEP CLEAR markings generate positive effects on the queuing vehicles in discharge on the main road. This finding refutes the traditional viewpoint that the KEEP CLEAR pavement markings will cause delay for the queuing vehicles’ departure due to the enlarged queue spacing. Further studies are suggested in this paper as well.
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I believe that studies of men's gendered experiences of information systems are needed. In order to support this claim, I introduce the area of Masculinity Studies to Information Systems research and, using this, present an exploratory analysis of an internet dating website for gay men – Gaydar. The information system, which forms part of the Gaydar community, is shown to shape, and be shaped by the members as they accept and challenge aspects of it as related to their identities. In doing this, I show how the intertwined processes of information systems development and use contribute to the creation of diverse interpretations of masculinity within a group of men. In sum, my analysis highlights different kinds of men and different versions of masculinity that can sometimes be associated with different experiences of information systems. The implications of this work centre on the need to expand our knowledge of men's gendered experiences with information systems, to reflect upon processes of technology facilitated categorisation and to consider the influences that contribute to the roll out of particular software features along with the underlying rationales for market segmentation in the software and software-based services industries.
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While user-generated short online videos have existed since the emergence of video sharing sites in China, they have undergone a process of formalisation and commercialisation, culminating in the wave of micro-movies in recent years. By addressing the wider context of globalisation alongside relevant state policies and shifting viewing habits, this article analyses the local and global causes of this wave. It offers evidence that illustrates how online video service providers in China have adapted in a changing industry landscape as they negotiate state policies, advertiser interests and user preference. It then examines the production and distribution dynamics, where professional producers draw on social media, grassroots creativity and creative talents in regional markets. Finally, it discusses the cultural implications of this process in terms of both the nature and flow of creativity. Based on these analyses, the article also sheds light on the interplay between the state and the market in the context of globalisation and marketisation of media sectors, which becomes more complicated when the state-owned or controlled media enter the emerging market sectors.