981 resultados para postgraduate


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Thin SiO2 interlayer is the key to improving the electroluminescence characteristics of light emitting diodes based on ZnO heterojunctions, but little is known of the band offsets of SiO2/ZnO. In this letter, energy band alignment of SiO2/ZnO interface was determined by x-ray photoelectron spectroscopy. The valence band offset Delta E-V of SiO2/ZnO interface is determined to be 0.93 +/- 0.15 eV. According to the relationship between the conduction band offset Delta E-C and the valence band offset Delta E-V Delta E-C=E-g(SiO2)-E-g(ZnO)-Delta E-V, and taking the room-temperature band-gaps of 9.0 and 3.37 eV for SiO2 and ZnO, respectively, a type-I band-energy alignment of SiO2/ZnO interface with a conduction band offset of 4.70 +/- 0.15 eV is found. The accurate determination of energy band alignment of SiO2/ZnO is helpful for designing of SiO2/ZnO hybrid devices and is also important for understanding their carrier transport properties. (C) 2009 American Institute of Physics. [DOI 10.1063/1.3204028]

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The Pt nanoparticles (NPs), which posses the wider tunable localized-surface-plasmon (LSP) energy varying from deep ultraviolet to visible region depending on their morphology, were prepared by annealing Pt thin films with different initial mass-thicknesses. A sixfold enhancement of the 357 nm forward emission of ZnMgO was observed after capping with Pt NPs, which is due to the resonance coupling between the LSP of Pt NPs and the band-gap emission of ZnMgO. The other factors affecting the ultraviolet emission of ZnMgO, such as emission from Pt itself and light multi-scattering at the interface, were also discussed. These results indicate that Pt NPs can be used to enhance the ultraviolet emission through the LSP coupling for various wide band-gap semiconductors.

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The ZnO films deposited by magnetron sputtering were treated by H/O plasma. It is found that the field emission (FE) characteristics of the ZnO film are considerably improved after H-plasma treatment and slightly deteriorated after O-plasma treatment. The improvement of FE characteristics is attributed to the reduced work function and the increased conductivity of the ZnO H films. Conductive atomic force microscopy was employed to investigate the effect of the plasma treatment on the nanoscale conductivity of ZnO, these findings correlate well with the FE data and facilitate a clearer description of electron emission from the ZnO H films.

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In the period of college, an individual matures rapidly in all aspects. College engineering students are the important parts of undergraduates. The state of an individual’s mental health may affect and even decide his future life and work. The level of the student’s self-concept and the kind of coping styles the students adopt are directly related to their mental health. So, it is significant to study the psychological stress, coping and self-concept of college engineering students for the mental health education and research of college engineering students. Based on overviews of former research, with the China College Student Psychological Stress Scale, the Coping Styles Scale and the Tennessee Self-Concept Scale, 559 college engineering students were investigated to explore the characteristics of and the relationship between the psychological stress, coping styles and self-concept of college engineering students. The results showed: 1. The stresses of learning, living and daily hassles were the main psychological stresses of college engineering students. There were significant differences in psychological stress between students from the countryside and those from urban areas, between needy students and non-needy students, between single-parent students and non-single-parent students, among students from different grades, with different academic achievements and of different postgraduate targets, between student party members and non-party members, between student cadres and non-cadres. However, there were no significant differences between male and female, between those from single-child families and from multiple-child families. 2. The coping styles of solving problem, seeking help and rationalization were the main coping styles of college engineering students. There were significant differences in the coping styles between needy students and non-needy students, among students from different grades, with different academic achievements and of different postgraduate targets, between student party members and non-party members, between student cadres and non-cadres. However, there were no significant differences between students from the countryside and from urban areas, between male and female, between single-parent students and non-single-parent students, between those from single-child families and from multiple-child families. 3. The self-concept of college engineering students was positive in general. There were significant differences in self-concept between students from the countryside and those from urban areas, between male and female, between needy students and non-needy students, between single-parent students and non-single-parent students, among students from different grades, with different academic achievements and of different postgraduate targets, between student party members and non-party members, between student cadres and non-cadres. However, there were no significant differences between those from single-child families and from multiple-child families. 4. The psychological stress had significantly negative correlation to the immature coping styles, and had partial correlation to the mature coping styles. Coping style has significant predictability on psychological stress. 5. The positive factors of the self-concept had significantly negative correlation to psychological stress, but self-criticism had positive correlation to psychological stress. There are significant differences between high self-concept students and low self-concept students for psychological stress. Self-concept has significant predictability on psychological stress. 6. The positive factors of the self-concept had significantly negative correlation to the coping styles of self-blame, illusion, avoidance, and rationalization, but had significantly positive correlation to the coping style of solving problem and seeking help. Self-criticism had significantly negative correlation to the coping styles of self-blame, illusion, avoidance, and rationalization. There are significant differences between high self-concept students and low self-concept students for coping styles. Self-concept has significant predictability on coping styles. 7. The self-concept of college engineering students had an effect on psychological stress by coping styles. However, the effect by the immature coping styles was higher than that to the mental health directly, and the effect by the mature and mixed coping styles was slighter than that to the mental health directly. According to the results, improving the college engineering students’ self-concept level and establishing right self-concept, developing the middle school student’ active coping styles and overcoming the negative coping styles are essential and important to the college engineering students’ mental health and provide useful clues for the psychological education of the college engineering students.

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The Scholarship of Teaching and Learning (SoTL) is being promoted as an activity for teaching-focused academics in the UK. However, support for SoTL is not a priority for most institutions, and formal provision for such support may not extend beyond the postgraduate certificate in higher education that is offered for new academic staff. This paper examines the experiences of SoTL of a group of twenty-one Life Sciences academics from a range of UK universities. It explores the role that SoTL has to play in developing classroom innovation in a structured and scholarly manner, and the consequences to both teaching staff and students, if SoTL is not supported as an academic activity throughout the careers of teaching-focused academics.

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Schofield, Phillipp, and N. J. Mayhew, eds., Credit and Debt in medieval England, c.1180-c.1350 (Oxford: Oxbow Books, 2002), pp.x+164 RAE2008

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This research asks the question: “What are the relational dynamics in Masters (MA) supervision?” It does so by focusing upon the supervisory relationship itself. It does this through dialoguing with the voices of both MA supervisors and supervisees in the Humanities using a Cultural Historical Activity Theory (CHAT) framework. In so doing, this research argues for a re-evaluation of how MA supervision is conceptualised and proposes a new theoretical framework for conceptualising MA supervision as a relational phenomenon. The research design was derived from an Activity Theory-influenced methodology. Data collection procedures included the administration of Activity Theory Logs, individual semi-structured interviews with both supervisors and supervisees and the completion of reflective journals. Grounded Theory was used to analyse the data. The sample for the study consists of three supervisor-supervisee dyads from three disciplines in the Humanities. Data was collected over the course of one academic year, 2010-2011. This research found that both individual and shared relational dynamics play an important role in MA supervision. Individual dynamics, such as supervisors’ iterative negotiation of ambiguity/clarity and supervisees’ boundary work, revealed that both parties attempt to negotiate a separation between their professional-academic identities and personal identities. However, an inherent paradox emerged when the shared relational dynamics of MA supervision were investigated. It was found that the shared space created by the supervisory relationship did not only exist in a physical setting, but was also psychoactive in nature and held strong emotional resonances for both parties involved. This served to undermine the separation between professional-academic and personal identities. As a result, this research argues that the interaction between the individual and shared relational dynamics in MA supervision enables, for both supervisors and supervisees, a disciplined improvisation of academic identity.

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Carbon nanotubes (CNTs) are hollow tubes of sp2-hybridised carbon with diameters of the order of nanometres. Due to their unique physical properties, which include ballistic transport and high mechanical strength, they are of significant interest for technological applications. The electronic properties of CNTs are of particular interest for use as gas sensors, interconnect materials in the semi-conductor industry and as the channel material in CNT based field effect transistors. The primary difficulty associated with the use of CNTs in electronic applications is the inability to control electronic properties at the growth stage; as grown CNTs consist of a mixture of metallic and semi-conducting CNTs. Doping has the potential to solve this problem and is a focus of this thesis. Nitrogen-doped CNTs typically have defective structures; the usual hollow CNT structure is replaced by a series of compartments. Through density functional theory (DFT) calculations and experimental results, we propose an explanation for the defective structures obtained, based on the stronger binding of N to the growth catalyst in comparison to C. In real electronic devices, CNTs need to be contacted to metal, we generate the current-voltage (IV) characteristics of metal-contacted CNTs considering both the effect of dopants and the structure of the interface region on electronic properties. We find that substitutionally doped CNTs produce Ohmic contacts and that scattering at the interface is strongly influenced by structure. In addition, we consider the effect of the common vacancy defects on the electronic properties of large diameter CNTs. Defects increase scattering in the CNT, with the greatest scattering occurring for the largest defect (555777). We validate the independent scattering approximation for small diameter CNTs, which enables mean free paths in large diameter CNTs to be calculated, with a smaller mean free paths found for larger defects.

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My research investigates a recent tendency in Italian literature, characterized by elements of renewal within the novel-writing tradition and of discontinuity with postmodern culture. It proposes an interpretation of the genres of the historical novel and crime fiction in the last fifteen years, in order to underline the important role played by these types of narrative in revitalizing contemporary Italian literature. These modalities of writing are considered both individually and in their connections beyond a traditional notion of genre, emphasizing those characteristics which may be assumed as irreconcilable with a postmodern approach to fiction and those which, furthermore, seem to indicate attempts to take a new course. In particular, my study analyses the recent literary tendency to combine the elements of ‘crime’ and ‘history’ in order to represent political and social reality, and how the works examined relate to postmodern narrative. For this reason, I pay particular attention to the relationship between literature and the past and to the socio-political aspects connected with the praxis of narrating, offering an original interpretation of the way in which the authors studied engage with these characteristics.

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Natural and human-made disasters cause on average 120,000 deaths and over US$140 billion in damage to property and infrastructure every year, with national, regional and international actors consistently responding to the humanitarian imperative to alleviate suffering wherever it may be found. Despite various attempts to codify international disaster laws since the 1920s, a right to humanitarian assistance remains contested, reflecting concerns regarding the relative importance of state sovereignty vis-à-vis individual rights under international law. However, the evolving acquis humanitaire of binding and non-binding normative standards for responses to humanitarian crises highlights the increasing focus on rights and responsibilities applicable in disasters; although the International Law Commission has also noted the difficulty of identifying lex lata and lex ferenda regarding the protection of persons in the event of disasters due to the “amorphous state of the law relating to international disaster response.” Therefore, using the conceptual framework of transnational legal process, this thesis analyses the evolving normative frameworks and standards for rights-holders and duty-bearers in disasters. Determining the process whereby rights are created and evolve, and their potential internalisation into domestic law and policy, provides a powerful analytical framework for examining the progress and challenges of developing accountable responses to major disasters.

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The North Carolinian author Thomas Wolfe (1900‐1938) has long suffered under the “charge of autobiography,” which lingers to this day in critical assessments of his work. Criticism of Wolfe is frequently concerned with questions of generic classification, but since the 1950s, re‐assessments of Wolfe’s work have suggested that Wolfe’s “autobiographical fiction” exhibits a complexity that merits further investigation. Strides in autobiographical and narrative theory have prompted reconsiderations of texts that defy the artificial boundaries of autobiography and fiction. Wolfe has been somewhat neglected in the canon of American fiction of his era, but deserves to be reconsidered in terms of how he engages with the challenges and contradictions of writing about or around the self. This thesis investigates why Wolfe’s work has been the source of considerable critical discomfort and confusion with regard to the relationship between Wolfe’s life and his writing. It explores this issue through an examination of elements of Wolfe’s work that problematise categorisation. Firstly, it investigates the concept of Wolfe as “storyteller.” It explores the motivations and philosophies that underpin Wolfe’s work and his concept of himself as a teller of tales, and examines aspects of Wolfe’s writing process that have their roots in medieval traditions of the memorisation and recitation of tales. The thesis then conducts a detailed examination of how Wolfe describes the process of transforming his memory into narrative through writing. The latter half of the thesis examines narrative techniques used by Wolfe, firstly analysing his extensive use of the iterative and pseudo‐iterative modes, and then his unusual deployment of narrators and focalization. This project sheds light on elements of Wolfe’s approach to writing and narrative strategies that he employs that have previously been overlooked, and that have created considerable critical confusion with regard to the supposedly “autobiographical” genesis of his work.

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The primary objective of this thesis is to examine the development of monetary policy and banking in southern Ireland from the attainment of independence in 1922 (gained through the Anglo-Irish Treaty of 1921) to the establishment of the Central Bank of Ireland in 1943. This research serves to challenge the overwhelming concentration on the findings of a small number of major works, most notably by Ronan Fanning, Maurice Moynihan and Cormac Ó’Gráda, in the existing historiography. This thesis is based on the research hypothesis that there were two key factors impacting on the development of monetary and banking institutions in Ireland in the 1922-1943 period. First, an exogenous institutional context, primarily Anglo-Irish in focus, in which the wider macroeconomic landscape directly influenced monetary policy and banking in Ireland. Second, an individualist context in which the development of relationships between key individuals dictated development patterns and institutional structures. This research highlights that key Irish policymakers, such as Joseph Brennan, evidenced a more flexible and realistic approach to banking and monetary affairs than is currently recognised. It also develops three further issues which have been overlooked in the existing historiography. First, a germ of monetary reform existed in Ireland from as early as the mid-1920s and was consistent in promoting alternative policies in the period to 1943. Second, this research challenges the view that the creation of the Currency Commission in 1927 and the establishment of the Central Bank of Ireland in 1943 were insignificant events given the continued stagnation in Irish monetary policy in the decades after 1943. Third, this thesis identifies that wider international trends did influence Irish monetary and banking affairs in the 1922-43 period. At both an institutional and more individual level the process of monetary institution building in Ireland was directly impacted by wider international experiences.

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This thesis critically investigates the divergent international approaches to the legal regulation of the patentability of computer software inventions, with a view to identifying the reforms necessary for a certain, predictable and uniform inter-jurisdictional system of protection. Through a critical analysis of the traditional and contemporary US and European regulatory frameworks of protection for computer software inventions, this thesis demonstrates the confusion and legal uncertainty resulting from ill-defined patent laws and inconsistent patent practices as to the scope of the “patentable subject matter” requirement, further compounded by substantial flaws in the structural configuration of the decision-making procedures within which the patent systems operate. This damaging combination prevents the operation of an accessible and effective Intellectual Property (IP) legal framework of protection for computer software inventions, capable of securing adequate economic returns for inventors whilst preserving the necessary scope for innovation and competition in the field, to the ultimate benefit of society. In exploring the substantive and structural deficiencies in the European and US regulatory frameworks, this thesis develops to ultimately highlight that the best approach to the reform of the legal regulation of software patentability is two-tiered. It demonstrates that any reform to achieve international legal harmony first requires the legislature to individually clarify (Europe) or restate (US) the long-standing inadequate rules governing the scope of software “patentable subject matter”, together with the reorganisation of the unworkable structural configuration of the decision-making procedures. Informed by the critical analysis of the evolution of the “patentable subject matter” requirement for computer software in the US, this thesis particularly considers the potential of the reforms of the European patent system currently underway, to bring about certainty, predictability and uniformity in the legal treatment of computer software inventions.

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Irish Research Council for Science, Engineering and Technology (Postgraduate scholarship Enterprise Partnership scheme in collaboration with Intel Ireland Ltd., funded under the National Development Plan)

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Ventral midbrain (VM) dopaminergic (DA) neurons, which project to the dorsal striatum via the nigrostriatal pathway, are progressively degenerated in Parkinson’s disease (PD). The identification of the instructive factors that regulate midbrain DA neuron development, and the subsequent elucidation of the molecular bases of their effects, is vital. Such an understanding would facilitate the generation of transplantable DA neurons from stem cells and the identification of developmentally-relevant neurotrophic factors, the two most promising therapeutic approaches for PD. Two related members of the bone morphogenetic protein (BMP) family, BMP2 and growth/differentiation factor (GDF) 5, which signal via a canonical Smad 1/5/8 signalling pathway, have been shown to have neurotrophic effects on midbrain DA neurons both in vitro and in vivo, and may function to regulate VM DA neuronal development. However, the molecular (signalling pathway(s)) and cellular (direct neuronal or indirect via glial cells) mechanisms of their effects remain to be elucidated. The present thesis hypothesised that canonical Smad signalling mediates the direct effects of BMP2 and GDF5 on the development of VM DA neurons. By activating, modulating and/or inhibiting various components of the BMP-Smad signalling pathway, this research demonstrated that GDF5- and BMP2-induced neurite outgrowth from midbrain DA neurons is dependent on BMP type I receptor activation of the Smad signalling pathway. The role of glial cell-line derived neurotrophic factor (GDNF)-signalling, dynamin-dependent endocytosis and Smad interacting protein-1 (Sip1) regulation, in the neurotrophic effects of BMP2 and GDF5 were determined. Finally, the in vitro development of VM neural stem cells (NSCs) was characterised, and the ability of GDF5 and BMP2 to induce these VM NSCs towards DA neuronal differentiation was investigated. Taken together, these experiments identify GDF5 and BMP2 as novel regulators of midbrain DA neuronal induction and differentiation, and demonstrate that their effects on DA neurons are mediated by canonical BMPR-Smad signalling.